WorldWideScience

Sample records for reacting chemical species

  1. Sensitive Diagnostics for Chemically Reacting Flows

    KAUST Repository

    Farooq, Aamir

    2015-01-01

    This talk will feature latest diagnostic developments for sensitive detection of gas temperature and important combustion species. Advanced optical strategies, such as intrapulse chirping, wavelength modulation, and cavity ringdown are employed.

  2. Sensitive Diagnostics for Chemically Reacting Flows

    KAUST Repository

    Farooq, Aamir

    2015-11-02

    This talk will feature latest diagnostic developments for sensitive detection of gas temperature and important combustion species. Advanced optical strategies, such as intrapulse chirping, wavelength modulation, and cavity ringdown are employed.

  3. Continuum-Kinetic Hybrid Framework for Chemically Reacting Flows

    Data.gov (United States)

    National Aeronautics and Space Administration — Predictive modeling of chemically reacting flows is essential for the design and optimization of future hypersonic vehicles. During atmospheric re-entry, complex...

  4. Evolution of a chemically reacting plume in a ventilated room

    Science.gov (United States)

    Conroy, D. T.; Smith, Stefan G. Llewellyn; Caulfield, C. P.

    2005-08-01

    The dynamics of a second-order chemical reaction in an enclosed space driven by the mixing produced by a turbulent buoyant plume are studied theoretically, numerically and experimentally. An isolated turbulent buoyant plume source is located in an enclosure with a single external opening. Both the source and the opening are located at the bottom of the enclosure. The enclosure is filled with a fluid of a given density with a fixed initial concentration of a chemical. The source supplies a constant volume flux of fluid of different density containing a different chemical of known and constant concentration. These two chemicals undergo a second-order non-reversible reaction, leading to the creation of a third product chemical. For simplicity, we restrict attention to the situation where the reaction process does not affect the density of the fluids involved. Because of the natural constraint of volume conservation, fluid from the enclosure is continually vented. We study the evolution of the various chemical species as they are advected by the developing ventilated filling box process within the room that is driven by the plume dynamics. In particular, we study both the mean and vertical distributions of the chemical species as a function of time within the room. We compare the results of analogue laboratory experiments with theoretical predictions derived from reduced numerical models, and find excellent agreement. Important parameters for the behaviour of the system are associated with the source volume flux and specific momentum flux relative to the source specific buoyancy flux, the ratio of the initial concentrations of the reacting chemical input in the plume and the reacting chemical in the enclosed space, the reaction rate of the chemicals and the aspect ratio of the room. Although the behaviour of the system depends on all these parameters in a non-trivial way, in general the concentration within the room of the chemical input at the isolated source passes

  5. Direct numerical simulation of turbulent, chemically reacting flows

    Science.gov (United States)

    Doom, Jeffrey Joseph

    This dissertation: (i) develops a novel numerical method for DNS/LES of compressible, turbulent reacting flows, (ii) performs several validation simulations, (iii) studies auto-ignition of a hydrogen vortex ring in air and (iv) studies a hydrogen/air turbulent diffusion flame. The numerical method is spatially non-dissipative, implicit and applicable over a range of Mach numbers. The compressible Navier-Stokes equations are rescaled so that the zero Mach number equations are discretely recovered in the limit of zero Mach number. The dependent variables are co--located in space, and thermodynamic variables are staggered from velocity in time. The algorithm discretely conserves kinetic energy in the incompressible, inviscid, non--reacting limit. The chemical source terms are implicit in time to allow for stiff chemical mechanisms. The algorithm is readily applicable to complex chemical mechanisms. Good results are obtained for validation simulations. The algorithm is used to study auto-ignition in laminar vortex rings. A nine species, nineteen reaction mechanism for H2/air combustion proposed by Mueller et al. [37] is used. Diluted H 2 at ambient temperature (300 K) is injected into hot air. The simulations study the effect of fuel/air ratio, oxidizer temperature, Lewis number and stroke ratio (ratio of piston stroke length to diameter). Results show that auto--ignition occurs in fuel lean, high temperature regions with low scalar dissipation at a 'most reactive' mixture fraction, zeta MR (Mastorakos et al. [32]). Subsequent evolution of the flame is not predicted by zetaMR; a most reactive temperature TMR is defined and shown to predict both the initial auto-ignition as well as subsequent evolution. For stroke ratios less than the formation number, ignition in general occurs behind the vortex ring and propagates into the core. At higher oxidizer temperatures, ignition is almost instantaneous and occurs along the entire interface between fuel and oxidizer. For stroke

  6. Turbulent diffusion of chemically reacting flows: Theory and numerical simulations.

    Science.gov (United States)

    Elperin, T; Kleeorin, N; Liberman, M; Lipatnikov, A N; Rogachevskii, I; Yu, R

    2017-11-01

    The theory of turbulent diffusion of chemically reacting gaseous admixtures developed previously [T. Elperin et al., Phys. Rev. E 90, 053001 (2014)PLEEE81539-375510.1103/PhysRevE.90.053001] is generalized for large yet finite Reynolds numbers and the dependence of turbulent diffusion coefficient on two parameters, the Reynolds number and Damköhler number (which characterizes a ratio of turbulent and reaction time scales), is obtained. Three-dimensional direct numerical simulations (DNSs) of a finite-thickness reaction wave for the first-order chemical reactions propagating in forced, homogeneous, isotropic, and incompressible turbulence are performed to validate the theoretically predicted effect of chemical reactions on turbulent diffusion. It is shown that the obtained DNS results are in good agreement with the developed theory.

  7. Study on flow characteristics of chemically reacting liquid jet

    International Nuclear Information System (INIS)

    Hong Seon Dae; Okamoto, Koji; Takata, Takashi; Yamaguchi, Akira

    2004-07-01

    Tube rupture accidents in steam generators of sodium-cooled fast breeder reactors are important for safety because the rupture may propagates to neighboring tubes due to sodium-water reaction. In order to clarify the thermal-hydraulic phenomena in the accidents, the flow pattern and the interface in multi-phase flow must be investigated. The JNC cooperative research scheme on the nuclear fuel cycle with the University of Tokyo has been carried to develop a simultaneous measurement system of concentration and velocity profiles and to evaluate influence of chemical reaction on mixing phenomena. In the experiments, aqueous liquor of acetic acid and ammonium hydroxide are selected as a simulant fluid instead of liquid sodium and water vapor. The following conclusions are obtained in this research. Laser Induced Fluorescence (LIF) technique was adopted to measure reacting zone and pH distribution in chemically reacting liquid round free jet. As a result, it was found that the chemical reaction, which took place at the interface between the jet and outer flow, suppressed the mixing phenomenon (in 2001 research). Dynamic Particle Image Velocimetry (PIV) method was developed to measure instantaneous velocity profile with high temporal resolution. In the Dynamic PIV, a high-speed video camera coupled with a high-speed laser pulse generator was implemented. A time-line trend of interfacial area in the free jet was investigated with the Dynamic PIV. This technique was also applied to a complicated geometry (in 2002 research). A new algorithms for image analysis was developed to evaluated the Dynamic PIV data in detail. The characteristics of the mixing phenomenon with reacting jet such as the turbulent kinetic energy and the Reynolds stress were estimated in a spatial and temporal spectrum (in 2003 research). (author)

  8. CFD analysis of hypersonic, chemically reacting flow fields

    Science.gov (United States)

    Edwards, T. A.

    1993-01-01

    Design studies are underway for a variety of hypersonic flight vehicles. The National Aero-Space Plane will provide a reusable, single-stage-to-orbit capability for routine access to low earth orbit. Flight-capable satellites will dip into the atmosphere to maneuver to new orbits, while planetary probes will decelerate at their destination by atmospheric aerobraking. To supplement limited experimental capabilities in the hypersonic regime, computational fluid dynamics (CFD) is being used to analyze the flow about these configurations. The governing equations include fluid dynamic as well as chemical species equations, which are being solved with new, robust numerical algorithms. Examples of CFD applications to hypersonic vehicles suggest an important role this technology will play in the development of future aerospace systems. The computational resources needed to obtain solutions are large, but solution adaptive grids, convergence acceleration, and parallel processing may make run times manageable.

  9. An experimental study on downstream of the transition of the chemically reacting liquid round free jet

    International Nuclear Information System (INIS)

    Hong, S.D.; Sugii, Y.; Okamoto, K.; Madarame, H.

    2002-01-01

    An experimental study was conducted on the chemically reacting liquid round free jet, Laser Induced Fluorescence (LIF) technique was adopted to evaluate the diffusion width of the jet into liquid streams. In the fluid engineering, it is very important to evaluate the characteristics of reacting jet for the safety of the nuclear reactor. In this study, the jet profile of downstream region far away from the transition point was evaluated, providing comparisons between reacting and non-reacting jet case. The concentration of the jet solution was varied from 0.01 mol/L to 0.5 mol/L in reacting cases. In the downstream far away from the transition point, the jet profiles between reacting cases and non-reacting cases were visualized quite different. It was concluded that the chemical reaction affects the momentum diffusion of the jet in the downstream region. (author)

  10. A quasi-linear formulation for chemically reacting compressible mixtures of imperfect gases

    Science.gov (United States)

    Lentini, D.

    2008-01-01

    A quasi-linear formulation is proposed for high-speed finite-rate chemically reacting mixtures of imperfect gases, i.e., thermally perfect gases with specific heat varying with temperature. It retains the same formalism of a well-tried counterpart formulation for perfect gases, which has been proven to be suited for application of accurate and fast algorithms. Equations for both quasi-monodimensional flows, and for axisymmetric viscous flows are presented. The approach is based on the definition of an appropriate function F of temperature and concentration, which allows to identify Riemann variables for the flow under consideration; the formulation also includes equations for the entropy and the mass fractions of the N chemical species present in the reacting mixture. The key function F must be computed by numerical quadrature, together with its derivatives with respect to the individual species mass fractions. An example of computation of these quantities is reported, with reference to conditions in the combustion chamber of the Vulcain engine powering the first stage of the Ariane 5 launcher. Such a computation is demonstrated to be both economic and accurate, thus proving the workability of the proposed approach. Further, an estimate of the variation of the mixture specific heat ratio with temperature is given, in order to underline the importance of the effect under consideration.

  11. Analysis of the trend to equilibrium of a chemically reacting system

    International Nuclear Information System (INIS)

    Kremer, Gilberto M; Bianchi, Miriam Pandolfi; Soares, Ana Jacinta

    2007-01-01

    In this present paper, a quaternary gaseous reactive mixture, for which the chemical reaction is close to its final stage and the elastic and reactive frequencies are comparable, is modelled within the Boltzmann equation extended to reacting gases. The main objective is a detailed analysis of the non-equilibrium effects arising in the reactive system A 1 + A 2 ↔ A 3 + A 4 , in a flow regime which is considered not far away from thermal, mechanical and chemical equilibrium. A first-order perturbation solution technique is applied to the macroscopic field equations for the spatially homogeneous gas system, and the trend to equilibrium is studied in detail. Adopting elastic hard-spheres and reactive line-of-centres cross sections and an appropriate choice of the input distribution functions-which allows us to distinguish the two cases where the constituents are either at same or different temperatures-explicit computations of the linearized production terms for mass, momentum and total energy are performed for each gas species. The departures from the equilibrium states of densities, temperatures and diffusion fluxes are characterized by small perturbations of their corresponding equilibrium values. For the hydrogen-chlorine system, the perturbations are plotted as functions of time for both cases where the species are either at the same or different temperatures. Moreover, the trend to equilibrium of the reaction rates is represented for the forward and backward reaction H 2 + Cl ↔ HCl + H

  12. COMPARACIÓN DEL MUESTREO DE ESPECIES QUÍMICAS EN ZONAS REACTIVAS MEDIANTE EL USO DE SONDA CON Y SIN CUELLO SÓNICO COMPARISON OF SAMPLING CHEMICAL SPECIES IN REACTING ZONES USING PROBES WITHOUT SONIC NOZZLE

    Directory of Open Access Journals (Sweden)

    Francisco Cadavid

    2010-08-01

    Full Text Available El análisis de los productos de combustión en las zonas de reacción y al interior de cámaras de combustión requiere, con respecto a las medidas efectuadas en chimeneas, de equipos y de métodos particulares de muestreo. Así por ejemplo, en las zonas donde hay presencia de llama se deben utilizar dispositivos experimentales no intrusivos, tales como las técnicas láser, o intrusivos como las sondas de muestreo. El empleo de los primeros implica altos costos mientras que el de los segundos deben garantizar que las reacciones de combustión no continúen al interior de la sonda pues de lo contrario se producen errores importantes en la medición. En este trabajo se presenta una comparación de los resultados obtenidos al realizar muestreos al interior de la zona de reacción de una llama de premezcla parcial empleando dos tipos de sondas: una con cuello sónico y enfriamiento convectivo de la muestra y la otra constituida simplemente por un tubo en acero inoxidable; para identificar si existen efectos térmicos y cinético - químicos que generen diferencias en la medición de las especies mayoritarias. Los resultados muestran que al emplear una sonda con un tubo liso se estarían presentando errores en las mediciones de CO2 y CO cercanos al 7,0% y en las de O2 superiores al 14%.The analysis of combustion products inside flames reaction zones and combustion chambers requires special equipment and methods of sampling compared to measurements made in chimneys. For example, non-intrusive experimental devices, such as laser techniques, or intrusive ones, such as sampling probes, should be used in zones where a flame is present. The use of the first ones means high costs, while the second ones must guarantee that the combustion reactions do not continue inside the sample probe; otherwise significant errors occur in the species measurements. To identify whether there are thermal and chemical kinetic effects that produce differences in the major

  13. Heat and mass transfer for turbulent flow of chemically reacting gas in eccentric annular channels

    International Nuclear Information System (INIS)

    Besedina, T.V.; Tverkovkin, B.E.; Udot, A.V.; Yakushev, A.P.

    1988-01-01

    Because of the possibility of using dissociating gases as coolants and working bodies of nuclear power plants, it is necessary to develop computational algorithms for calculating heat and mass transfer processes under conditions of nonequilibrium flow of chemically reacting gases not only in axisymmetric channels, but also in channels with a complex transverse cross section (including also in eccentric annular channels). An algorithm is proposed for calculating the velocity, temperature, and concentration fields under conditions of cooling of a cylindrical heat-releasing rod, placed off-center in a circular casing pipe, by a longitudinal flow of chemically reacting gas [N 2 O 4

  14. Computer program to solve two-dimensional shock-wave interference problems with an equilibrium chemically reacting air model

    Science.gov (United States)

    Glass, Christopher E.

    1990-08-01

    The computer program EASI, an acronym for Equilibrium Air Shock Interference, was developed to calculate the inviscid flowfield, the maximum surface pressure, and the maximum heat flux produced by six shock wave interference patterns on a 2-D, cylindrical configuration. Thermodynamic properties of the inviscid flowfield are determined using either an 11-specie, 7-reaction equilibrium chemically reacting air model or a calorically perfect air model. The inviscid flowfield is solved using the integral form of the conservation equations. Surface heating calculations at the impingement point for the equilibrium chemically reacting air model use variable transport properties and specific heat. However, for the calorically perfect air model, heating rate calculations use a constant Prandtl number. Sample calculations of the six shock wave interference patterns, a listing of the computer program, and flowcharts of the programming logic are included.

  15. A mathematical model for chemical reactions with actinide elements in the aqueous nitric acid solution: REACT

    International Nuclear Information System (INIS)

    Tachimori, Shoichi

    1990-02-01

    A mathematical model of chemical reactions with actinide elements: REACT code, was developed to simulate change of valency states of U, Pu and Np in the aqueous nitric acid solution. Twenty seven rate equations for the redox reactions involving some reductants, disproportionation reactions, and radiolytic growth and decay reaction of nitrous acid were programmed in the code . Eight numerical solution methods such as Porsing method to solve the rate equations were incorporated parallel as options depending on the characteristics of the reaction systems. The present report gives a description of the REACT code, e.g., chemical reactions and their rate equations, numerical solution methods, and some examples of the calculation results. A manual and a source file of the program was attached to the appendix. (author)

  16. A Parallel Multiblock Structured Grid Method with Automated Interblocked Unstructured Grids for Chemically Reacting Flows

    Science.gov (United States)

    Spiegel, Seth Christian

    An automated method for using unstructured grids to patch non- C0 interfaces between structured blocks has been developed in conjunction with a finite-volume method for solving chemically reacting flows on unstructured grids. Although the standalone unstructured solver, FVFLO-NCSU, is capable of resolving flows for high-speed aeropropulsion devices with complex geometries, unstructured-mesh algorithms are inherently inefficient when compared to their structured counterparts. However, the advantages of structured algorithms in developing a flow solution in a timely manner can be negated by the amount of time required to develop a mesh for complex geometries. The global domain can be split up into numerous smaller blocks during the grid-generation process to alleviate some of the difficulties in creating these complex meshes. An even greater abatement can be found by allowing the nodes on abutting block interfaces to be nonmatching or non-C 0 continuous. One code capable of solving chemically reacting flows on these multiblock grids is VULCAN, which uses a nonconservative approach for patching non-C0 block interfaces. The developed automated unstructured-grid patching algorithm has been installed within VULCAN to provide it the capability of a fully conservative approach for patching non-C0 block interfaces. Additionally, the FVFLO-NCSU solver algorithms have been deeply intertwined with the VULCAN source code to solve chemically reacting flows on these unstructured patches. Finally, the CGNS software library was added to the VULCAN postprocessor so structured and unstructured data can be stored in a single compact file. This final upgrade to VULCAN has been successfully installed and verified using test cases with particular interest towards those involving grids with non- C0 block interfaces.

  17. Combined LAURA-UPS solution procedure for chemically-reacting flows. M.S. Thesis

    Science.gov (United States)

    Wood, William A.

    1994-01-01

    A new procedure seeks to combine the thin-layer Navier-Stokes solver LAURA with the parabolized Navier-Stokes solver UPS for the aerothermodynamic solution of chemically-reacting air flowfields. The interface protocol is presented and the method is applied to two slender, blunted shapes. Both axisymmetric and three dimensional solutions are included with surface pressure and heat transfer comparisons between the present method and previously published results. The case of Mach 25 flow over an axisymmetric six degree sphere-cone with a noncatalytic wall is considered to 100 nose radii. A stability bound on the marching step size was observed with this case and is attributed to chemistry effects resulting from the noncatalytic wall boundary condition. A second case with Mach 28 flow over a sphere-cone-cylinder-flare configuration is computed at both two and five degree angles of attack with a fully-catalytic wall. Surface pressures are seen to be within five percent with the present method compared to the baseline LAURA solution and heat transfers are within 10 percent. The effect of grid resolution is investigated and the nonequilibrium results are compared with a perfect gas solution, showing that while the surface pressure is relatively unchanged by the inclusion of reacting chemistry the nonequilibrium heating is 25 percent higher. The procedure demonstrates significant, order of magnitude reductions in solution time and required memory for the three dimensional case over an all thin-layer Navier-Stokes solution.

  18. Separation of chemical species

    International Nuclear Information System (INIS)

    Rentzepis, P.M.

    1977-01-01

    Isotopic separation is accomplished by (1) a second photon irradiation step for selective ionization of a first isotopic species and (2) selective precipitation of a generally immiscible liquid from the saturating vapor phase on the ionized species. The first photon corresponds with a sharply defined spectral portion of the irradiation which exclusively excites the first species to a vibrational level. The second photon further excites this species to its ionization level. Selective precipitation is by coulombic attraction between the ionized species and the vapor. The procedure is applicable to any vapor phase ionizable material

  19. Steam bubble growth in the bulk of overheated N2O4-NO chemically reacting solution

    International Nuclear Information System (INIS)

    Nemtsev, V.A.; Cherkashin, A.M.

    1989-01-01

    A mathematical model and numerical investigation of the vapour bubble growth that begins from the bubble critical size at the positive radius fluctuation during the initial moment in the bulk of the overheated N 2 O 4 -NO liquid solution are presented. The mathematical model has been stated under the following assumptions: the movement of a bubble wall and surrounding liquid is spherically symmetrical; thermal parameters in the bubble are distributed uniformly; the vapour phase follows the ideal gas law; heat transfer is not affected by the compressibility of liquid; if dissolution of light components is determined by Henry's law, then Hertz-Knudsen's equation determines the velocity of phase transition for a N 2 O 4 component. The mathematical model presented can be applied to another fluids, including chemically reacting ones

  20. Wildfire simulation using a chemically-reacting plume in a crossflow

    Science.gov (United States)

    Breidenthal, Robert; Alvarado, Travis; Potter, Brian

    2010-11-01

    Water tunnel experiments reveal the flame length of a chemically-reacting plume in a crossflow. Salt water containing a pH indicator and a base is slowly injected from above into the test section of a water tunnel containing an acidic solution. The flame length is measured optically as a function of the buoyancy flux, crossflow speed, and volume equivalence ratio of the chemical reaction. Based on earlier work of Broadwell with the transverse jet, a simple dilution model predicts the flame length of the transverse plume. The plume observations are in accord with the model. As with the jet, there is a minimum in the flame length of the plume at a transition between two self-similar regimes, corresponding to the formation of a pair of counter-rotating vortices at a certain crossflow speed. At the transition, there is a maximum in the entrainment and mixing rates. In an actual wildfire with variable winds, this transition may correspond to a dangerous condition for firefighters.

  1. Thermodynamic Analysis of Chemically Reacting Mixtures-Comparison of First and Second Order Models.

    Science.gov (United States)

    Pekař, Miloslav

    2018-01-01

    Recently, a method based on non-equilibrium continuum thermodynamics which derives thermodynamically consistent reaction rate models together with thermodynamic constraints on their parameters was analyzed using a triangular reaction scheme. The scheme was kinetically of the first order. Here, the analysis is further developed for several first and second order schemes to gain a deeper insight into the thermodynamic consistency of rate equations and relationships between chemical thermodynamic and kinetics. It is shown that the thermodynamic constraints on the so-called proper rate coefficient are usually simple sign restrictions consistent with the supposed reaction directions. Constraints on the so-called coupling rate coefficients are more complex and weaker. This means more freedom in kinetic coupling between reaction steps in a scheme, i.e., in the kinetic effects of other reactions on the rate of some reaction in a reacting system. When compared with traditional mass-action rate equations, the method allows a reduction in the number of traditional rate constants to be evaluated from data, i.e., a reduction in the dimensionality of the parameter estimation problem. This is due to identifying relationships between mass-action rate constants (relationships which also include thermodynamic equilibrium constants) which have so far been unknown.

  2. A constrained approach to multiscale stochastic simulation of chemically reacting systems

    KAUST Repository

    Cotter, Simon L.

    2011-01-01

    Stochastic simulation of coupled chemical reactions is often computationally intensive, especially if a chemical system contains reactions occurring on different time scales. In this paper, we introduce a multiscale methodology suitable to address this problem, assuming that the evolution of the slow species in the system is well approximated by a Langevin process. It is based on the conditional stochastic simulation algorithm (CSSA) which samples from the conditional distribution of the suitably defined fast variables, given values for the slow variables. In the constrained multiscale algorithm (CMA) a single realization of the CSSA is then used for each value of the slow variable to approximate the effective drift and diffusion terms, in a similar manner to the constrained mean-force computations in other applications such as molecular dynamics. We then show how using the ensuing Fokker-Planck equation approximation, we can in turn approximate average switching times in stochastic chemical systems. © 2011 American Institute of Physics.

  3. An implicit multigrid algorithm for computing hypersonic, chemically reacting viscous flows

    International Nuclear Information System (INIS)

    Edwards, J.R.

    1996-01-01

    An implicit algorithm for computing viscous flows in chemical nonequilibrium is presented. Emphasis is placed on the numerical efficiency of the time integration scheme, both in terms of periteration workload and overall convergence rate. In this context, several techniques are introduced, including a stable, O(m 2 ) approximate factorization of the chemical source Jacobian and implementations of V-cycle and filtered multigrid acceleration methods. A five species-seventeen reaction air model is used to calculate hypersonic viscous flow over a cylinder at conditions corresponding to flight at 5 km/s, 60 km altitude and at 11.36 km/s, 76.42 km altitude. Inviscid calculations using an eleven-species reaction mechanism including ionization are presented for a case involving 11.37 km/s flow at an altitude of 84.6 km. Comparisons among various options for the implicit treatment of the chemical source terms and among different multilevel approaches for convergence acceleration are presented for all simulations

  4. Extension of a semi-implicit shock-capturing algorithm for 3-D fully coupled, chemically reacting flows in generalized coordinates

    International Nuclear Information System (INIS)

    Shinn, J.L.; Yee, H.C.; Uenishi, K.; NASA, Ames Research Center, Moffett Field, CA; Vigyan Research Associates, Inc., Hampton, VA)

    1987-01-01

    A semiimplicit high-resolution shock-capturing method for multidimensional systems of hyperbolic conservation laws with stiff source terms has been developed by Yee and Shinn (1987). The goal of this work is to extend this method to solve the three-dimensional fully coupled Navier-Stokes equations for a hypersonic chemically reacting flow in generalized coordinates. In this formulation, the global continuity equation was replaced by all the species continuity equations. The shock-capturing technique is a second-order-accurate, symmetric total-variation-diminishing method which accounts fully and directly for the coupling among the fluid and all the species. To verify the current approach, it was implemented into an existing computer code which contained the MacCormack method. Test results for a five-species reacting flow are shown to be oscillation-free around the shock, and the time spent per iteration only doubles when compared to the result using classical way of supplying numerical dissipation. The extra computation is more than justified by the elimination of spurious oscillation and nonlinear instability associated with the classical shock-capturing schemes in computing hypersonic reacting flows. 27 references

  5. Reaction Ensemble Molecular Dynamics: Direct Simulation of the Dynamic Equilibrium Properties of Chemically Reacting Mixtures

    Czech Academy of Sciences Publication Activity Database

    Brennan, J.K.; Lísal, Martin; Gubbins, K.E.; Rice, B.M.

    2004-01-01

    Roč. 70, č. 6 (2004), 0611031-0611034 ISSN 1063-651X R&D Projects: GA ČR GA203/03/1588 Grant - others:NSF(US) CTS-0211792 Institutional research plan: CEZ:AV0Z4072921 Keywords : reacting systems * simulation * molecular dynamics Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.352, year: 2004

  6. From Detailed Description of Chemical Reacting Carbon Particles to Subgrid Models for CFD

    Directory of Open Access Journals (Sweden)

    Schulze S.

    2013-04-01

    Full Text Available This work is devoted to the development and validation of a sub-model for the partial oxidation of a spherical char particle moving in an air/steam atmosphere. The particle diameter is 2 mm. The coal particle is represented by moisture- and ash-free nonporous carbon while the coal rank is implemented using semi-global reaction rate expressions taken from the literature. The submodel includes six gaseous chemical species (O2, CO2, CO, H2O, H2, N2. Three heterogeneous reactions are employed, along with two homogeneous semi-global reactions, namely carbon monoxide oxidation and the water-gas-shift reaction. The distinguishing feature of the subgrid model is that it takes into account the influence of homogeneous reactions on integral characteristics such as carbon combustion rates and particle temperature. The sub-model was validated by comparing its results with a comprehensive CFD-based model resolving the issues of bulk flow and boundary layer around the particle. In this model, the Navier-Stokes equations coupled with the energy and species conservation equations were used to solve the problem by means of the pseudo-steady state approach. At the surface of the particle, the balance of mass, energy and species concentration was applied including the effect of the Stefan flow and heat loss due to radiation at the surface of the particle. Good agreement was achieved between the sub-model and the CFD-based model. Additionally, the CFD-based model was verified against experimental data published in the literature (Makino et al. (2003 Combust. Flame 132, 743-753. Good agreement was achieved between numerically predicted and experimentally obtained data for input conditions corresponding to the kinetically controlled regime. The maximal discrepancy (10% between the experiments and the numerical results was observed in the diffusion-controlled regime. Finally, we discuss the influence of the Reynolds number, the ambient O2 mass fraction and the ambient

  7. A constrained approach to multiscale stochastic simulation of chemically reacting systems

    KAUST Repository

    Cotter, Simon L.; Zygalakis, Konstantinos C.; Kevrekidis, Ioannis G.; Erban, Radek

    2011-01-01

    Stochastic simulation of coupled chemical reactions is often computationally intensive, especially if a chemical system contains reactions occurring on different time scales. In this paper, we introduce a multiscale methodology suitable to address

  8. Numerical Modeling of Mixing of Chemically Reacting, Non-Newtonian Slurry for Tank Waste Retrieval

    International Nuclear Information System (INIS)

    Yuen, David A.; Onishi, Yasuo; Rustad, James R.; Michener, Thomas E.; Felmy, Andrew R.; Ten, Arkady A.; Hier, Catherine A.

    2000-01-01

    Many highly radioactive wastes will be retrieved by installing mixer pumps that inject high-speed jets to stir up the sludge, saltcake, and supernatant liquid in the tank, blending them into a slurry. This slurry will then be pumped out of the tank into a waste treatment facility. Our objectives are to investigate interactions-chemical reactions, waste rheology, and slurry mixing-occurring during the retrieval operation and to provide a scientific basis for the waste retrieval decision-making process. Specific objectives are to: (1) Evaluate numerical modeling of chemically active, non-Newtonian tank waste mixing, coupled with chemical reactions and realistic rheology; (2) Conduct numerical modeling analysis of local and global mixing of non-Newtonian and Newtonian slurries; and (3) Provide the bases to develop a scientifically justifiable, decision-making support tool for the tank waste retrieval operation

  9. Numerical Modeling of Mixing of Chemically Reacting, Non-Newtonian Slurry for Tank Waste Retrieval

    International Nuclear Information System (INIS)

    Yuen, D.A.; Onishi, Y.

    2001-01-01

    In the U.S. Department of Energy (DOE) complex, 100 million gallons of radioactive and chemical wastes from plutonium production are stored in 281 underground storage tanks. Retrieval of the wastes from the tanks is the first step in its ultimate treatment and disposal. Because billions of dollars are being spent on this effort, waste retrieval demands a strong scientific basis for its successful completion. As will be discussed in Section 4.2, complex interactions among waste chemical reactions, rheology, and mixing of solid and liquid tank waste (and possibly with a solvent) will occur in DSTs during the waste retrieval (mixer pump) operations. The ultimate goal of this study was to develop the ability to simulate the complex chemical and rheological changes that occur in the waste during processing for retrieval. This capability would serve as a scientific assessment tool allowing a priori evaluation of the consequences of proposed waste retrieval operations. Hanford tan k waste is a multiphase, multicomponent, high-ionic strength, and highly basic mixture of liquids and solids. Wastes stored in the 4,000-m3 DSTs will be mixed by 300-hp mixer pumps that inject high-speed (18.3 m/s) jets to stir up the sludge and supernatant liquid for retrieval. During waste retrieval operations, complex interactions occur among waste mixing, chemical reactions, and associated rheology. Thus, to determine safe and cost-effective operational parameters for waste retrieval, decisions must rely on new scientific knowledge to account for physical mixing of multiphase flows, chemical reactions, and waste rheology. To satisfy this need, we integrated a computational fluid dynamics code with state-of-the-art equilibrium and kinetic chemical models and non-Newtonian rheology (Onishi (and others) 1999). This development is unique and holds great promise for addressing the complex phenomena of tank waste retrieval. The current model is, however, applicable only to idealized tank waste

  10. Chemically reacting flow of a compressible thermally radiating two-component plasma

    International Nuclear Information System (INIS)

    Bestman, A.R.

    1990-12-01

    The paper studies the compressible flow of a hot two-component plasma in the presence of gravitation and chemical reaction in a vertical channel. For the optically thick gas approximation, closed form analytical solutions are possible. Asymptotic solutions are also obtained for the general differential approximation when the temperature of the two bounding walls are the same. In the general case the problem is reduced to the solution of standard nonlinear integral equations which can be tackled by iterative procedure. The results are discussed quantitatively. The problem may be applicable to the understanding of explosive hydrogen-burning model of solar flares. (author). 6 refs, 4 figs

  11. Radiated flow of chemically reacting nanoliquid with an induced magnetic field across a permeable vertical plate

    Directory of Open Access Journals (Sweden)

    B. Mahanthesh

    Full Text Available Impact of induced magnetic field over a flat porous plate by utilizing incompressible water-copper nanoliquid is examined analytically. Flow is supposed to be laminar, steady and two-dimensional. The plate is subjected to a regular free stream velocity as well as suction velocity. Flow formulation is developed by considering Maxwell–Garnetts (MG and Brinkman models of nanoliquid. Impacts of thermal radiation, viscous dissipation, temperature dependent heat source/sink and first order chemical reaction are also retained. The subjected non-linear problems are non-dimensionalized and analytic solutions are presented via series expansion method. The graphs are plotted to analyze the influence of pertinent parameters on flow, magnetism, heat and mass transfer fields as well as friction factor, current density, Nusselt and Sherwood numbers. It is found that friction factor at the plate is more for larger magnetic Prandtl number. Also the rate of heat transfer decayed with increasing nanoparticles volume fraction and the strength of magnetism. Keywords: Induced magnetic field, Nanoliquids, Heat source/sink, Series expansion method, Chemical reaction, Thermal radiation

  12. A second-order coupled immersed boundary-SAMR construction for chemically reacting flow over a heat-conducting Cartesian grid-conforming solid

    KAUST Repository

    Kedia, Kushal S.; Safta, Cosmin; Ray, Jaideep; Najm, Habib N.; Ghoniem, Ahmed F.

    2014-01-01

    In this paper, we present a second-order numerical method for simulations of reacting flow around heat-conducting immersed solid objects. The method is coupled with a block-structured adaptive mesh refinement (SAMR) framework and a low-Mach number operator-split projection algorithm. A "buffer zone" methodology is introduced to impose the solid-fluid boundary conditions such that the solver uses symmetric derivatives and interpolation stencils throughout the interior of the numerical domain; irrespective of whether it describes fluid or solid cells. Solid cells are tracked using a binary marker function. The no-slip velocity boundary condition at the immersed wall is imposed using the staggered mesh. Near the immersed solid boundary, single-sided buffer zones (inside the solid) are created to resolve the species discontinuities, and dual buffer zones (inside and outside the solid) are created to capture the temperature gradient discontinuities. The development discussed in this paper is limited to a two-dimensional Cartesian grid-conforming solid. We validate the code using benchmark simulations documented in the literature. We also demonstrate the overall second-order convergence of our numerical method. To demonstrate its capability, a reacting flow simulation of a methane/air premixed flame stabilized on a channel-confined bluff-body using a detailed chemical kinetics model is discussed. © 2014 Elsevier Inc.

  13. A second-order coupled immersed boundary-SAMR construction for chemically reacting flow over a heat-conducting Cartesian grid-conforming solid

    KAUST Repository

    Kedia, Kushal S.

    2014-09-01

    In this paper, we present a second-order numerical method for simulations of reacting flow around heat-conducting immersed solid objects. The method is coupled with a block-structured adaptive mesh refinement (SAMR) framework and a low-Mach number operator-split projection algorithm. A "buffer zone" methodology is introduced to impose the solid-fluid boundary conditions such that the solver uses symmetric derivatives and interpolation stencils throughout the interior of the numerical domain; irrespective of whether it describes fluid or solid cells. Solid cells are tracked using a binary marker function. The no-slip velocity boundary condition at the immersed wall is imposed using the staggered mesh. Near the immersed solid boundary, single-sided buffer zones (inside the solid) are created to resolve the species discontinuities, and dual buffer zones (inside and outside the solid) are created to capture the temperature gradient discontinuities. The development discussed in this paper is limited to a two-dimensional Cartesian grid-conforming solid. We validate the code using benchmark simulations documented in the literature. We also demonstrate the overall second-order convergence of our numerical method. To demonstrate its capability, a reacting flow simulation of a methane/air premixed flame stabilized on a channel-confined bluff-body using a detailed chemical kinetics model is discussed. © 2014 Elsevier Inc.

  14. Nanoscale chemical state analysis of resistance random access memory device reacting with Ti

    Science.gov (United States)

    Shima, Hisashi; Nakano, Takashi; Akinaga, Hiro

    2010-05-01

    The thermal stability of the resistance random access memory material in the reducing atmosphere at the elevated temperature was improved by the addition of Ti. The unipolar resistance switching before and after the postdeposition annealing (PDA) process at 400 °C was confirmed in Pt/CoO/Ti(5 nm)/Pt device, while the severe degradation of the initial resistance occurs in the Pt/CoO/Pt and Pt/CoO/Ti(50 nm)/Pt devices. By investigating the chemical bonding states of Co, O, and Ti using electron energy loss spectroscopy combined with transmission electron microscopy, it was revealed that excess Ti induces the formation of metallic Co, while the thermal stability was improved by trace Ti. Moreover, it was indicated that the filamentary conduction path can be thermally induced after PDA in the oxide layer by analyzing electrical properties of the degraded devices. The adjustment of the reducing elements is quite essential in order to participate in their profits.

  15. Alcohols react with MCM-41 at room temperature and chemically modify mesoporous silica.

    Science.gov (United States)

    Björklund, Sebastian; Kocherbitov, Vitaly

    2017-08-30

    Mesoporous silica has received much attention due to its well-defined structural order, high surface area, and tunable pore diameter. To successfully employ mesoporous silica for nanotechnology applications it is important to consider how it is influenced by solvent molecules due to the fact that most preparation procedures involve treatment in various solvents. In the present work we contribute to this important topic with new results on how MCM-41 is affected by a simple treatment in alcohol at room temperature. The effects of alcohol treatment are characterized by TGA, FTIR, and sorption calorimetry. The results are clear and show that treatment of MCM-41 in methanol, ethanol, propanol, butanol, pentanol, or octanol at room temperature introduces alkoxy groups that are covalently bound to the silica surface. It is shown that alcohol treated MCM-41 becomes more hydrophobic and that this effect is sequentially more prominent going from methanol to octanol. Chemical formation of alkoxy groups onto MCM-41 occurs both for calcined and hydroxylated MCM-41 and the alkoxy groups are hydrolytically unstable and can be replaced by silanol groups after exposure to water. The results are highly relevant for mesoporous silica applications that involve contact or treatment in protic solvents, which is very common.

  16. Approximate method of calculation of non-equilibrium flow parameters of chemically reacting nitrogen tetroxide in the variable cross-section channels with energy exchange

    International Nuclear Information System (INIS)

    Bazhin, M.A.; Fedosenko, G.Eh.; Shiryaeva, N.M.; Mal'ko, M.V.

    1986-01-01

    It is shown that adiabatic non-equilibrium chemically reacting gas flow with energy exchange in a variable cross-section channel may be subdivided into five possible types: 1) quasi-equilibrium flow; 2) flow in the linear region of deviation from equilibrium state; 3) quasi-frozen flow; 4) flow in the linear region of deviation from frozen state; 5) non-equilibrium flow. Criteria of quasi-equilibrium and quazi-frozen flows, including factors of external action of chemically reacting gas on flow, allow to obtain simple but sufficiently reliable approximate method of calculation of flow parameters. The considered method for solving the problem of chemically reacting nitrogen tetroxide in the variable cross-section channel with energy exchange can be used for evaluation of chemical reaction kinetics on the flow parameter in the stages of axial-flow and radial-flow turbines and in another practical problems

  17. Lie Group Solution for Free Convective Flow of a Nanofluid Past a Chemically Reacting Horizontal Plate in a Porous Media

    Directory of Open Access Journals (Sweden)

    M. M. Rashidi

    2014-01-01

    Full Text Available The optimal homotopy analysis method (OHAM is employed to investigate the steady laminar incompressible free convective flow of a nanofluid past a chemically reacting upward facing horizontal plate in a porous medium taking into account heat generation/absorption and the thermal slip boundary condition. Using similarity transformations developed by Lie group analysis, the continuity, momentum, energy, and nanoparticle volume fraction equations are transformed into a set of coupled similarity equations. The OHAM solutions are obtained and verified by numerical results using a Runge-Kutta-Fehlberg fourth-fifth order method. The effect of the emerging flow controlling parameters on the dimensionless velocity, temperature, and nanoparticle volume fraction have been presented graphically and discussed. Good agreement is found between analytical and numerical results of the present paper with published results. This close agreement supports our analysis and the accuracy of the numerical computations. This paper also includes a representative set of numerical results for reduced Nusselt and Sherwood numbers in a table for various values of the parameters. It is concluded that the reduced Nusselt number increases with the Lewis number and reaction parameter whist it decreases with the order of the chemical reaction, thermal slip, and generation parameters.

  18. Use of the nonsteady monotonic heating method for complex determination of thermophysical properties of chemically reacting mixture in the case of non-equilibrium proceeding of the chemical reaction

    International Nuclear Information System (INIS)

    Serebryanyj, G.Z.

    1984-01-01

    Theoretical analysis is made for the monotonic heating method as applied for complex determination of thermophysical properties of chemically reacting gases. The possibility is shown of simultaneous determination of frozen and equilibrium heat capacity, frozen and equilibrium heat conduction provided non-equilibrium occuring of the reaction in the wide range of temperatures and pressures. The monotonic heating method can be used for complex determination of thermophysical properties of chemically reacting systems in case of non-equilibrium proceeding of the chemical reaction

  19. Molecular activation analysis for chemical species studies

    International Nuclear Information System (INIS)

    Chai Zhifang; Mao Xueying; Wang Yuqi; Sun Jingxin; Qian Qingfang; Hou Xiaolin; Zhang Peiqun; Chen Chunying; Feng Weiyu; Ding Wenjun; Li Xiaolin; Li Chunsheng; Dai Xiongxin

    2001-01-01

    The Molecular Activation Analysis (MAA) mainly refers to an activation analysis method that is able to provide information about the chemical species of elements in systems of interest, though its exact definition has remained to be assigned. Its development is strongly stimulated by the urgent need to know the chemical species of elements, because the bulk contents or concentrations are often insignificant for judging biological, environmental or geochemical effects of elements. In this paper, the features, methodology and limitation of MAA were outlined. Further, the up-to-date MAA progress made in our laboratory was introduced as well. (author)

  20. REACT-Mod: a mathematical model for transient calculation of chemical reactions with U-Pu-Np-Tc in the aqueous nitric acid solution

    International Nuclear Information System (INIS)

    Tachimori, Shoichi; Kitamura, Tatsuaki.

    1996-10-01

    A computer code REACT-Mod which simulates various chemical reactions in an aqueous nitric acid solution involving uranium, plutonium, neptunium, technetium etc. e.g., redox, radiolytic and disproportionation reactions of 68, was developed based on the kinetics model. The numerical solution method adopted in the code are two, a kinetics model totally based on the rate law of which differential equations are solved by the modified Porsing method, and a two-step model based on both the rate law and equilibrium law. Only the former treats 27 radiolytic reactions. The latter is beneficially used to have a quick and approximate result by economical computation. The present report aims not only to explain the concept, chemical reactions treated and characteristics of the model but also to provide details of the program for users of the REACT-Mod code. (author)

  1. Laminar or turbulent boundary-layer flows of perfect gases or reacting gas mixtures in chemical equilibrium

    Science.gov (United States)

    Anderson, E. C.; Lewis, C. H.

    1971-01-01

    Turbulent boundary layer flows of non-reacting gases are predicted for both interal (nozzle) and external flows. Effects of favorable pressure gradients on two eddy viscosity models were studied in rocket and hypervelocity wind tunnel flows. Nozzle flows of equilibrium air with stagnation temperatures up to 10,000 K were computed. Predictions of equilibrium nitrogen flows through hypervelocity nozzles were compared with experimental data. A slender spherically blunted cone was studied at 70,000 ft altitude and 19,000 ft/sec. in the earth's atmosphere. Comparisons with available experimental data showed good agreement. A computer program was developed and fully documented during this investigation for use by interested individuals.

  2. Analysis of chemical constituents in Cistanche species.

    Science.gov (United States)

    Jiang, Yong; Tu, Peng-Fei

    2009-03-13

    Species of the genus of Cistanche (Rou Cong Rong in Chinese) are perennial parasite herbs, and are mainly distributed in arid lands and warm deserts. As a superior tonic for the treatment of kidney deficiency, impotence, female infertility, morbid leucorrhea, profuse metrorrhagia and senile constipation, Cistanche herbs earned the honor of "Ginseng of the desert". Recently, there has been increasing scientific attention on Herba Cistanche for its remarkable bioactivities including antioxidation, neuroprotection, and anti-aging. The chemical constituents of Cistanche plants mainly include volatile oils and non-volatile phenylethanoid glycosides (PhGs), iridoids, lignans, alditols, oligosaccharides and polysaccharides. Pharmacological studies show that PhGs are the main active components for curing kidney deficiency, antioxidation and neuroprotection; galactitol and oligosaccharides are the representatives for the treatment of senile constipation, while polysaccharides are responsible for improving body immunity. In this paper, the advances on the chemical constituents of Cistanche plants and their corresponding analyses are reviewed.

  3. Chemical reaction rates and non-equilibrium pressure of reacting gas mixtures in the state-to-state approach

    International Nuclear Information System (INIS)

    Kustova, Elena V.; Kremer, Gilberto M.

    2014-01-01

    Highlights: • State-to-state approach for coupled vibrational relaxation and chemical reactions. • Self-consistent model for rates of non-equilibrium reactions and energy transitions. • In viscous flows mass action law is violated. • Cross coupling between reaction rates and non-equilibrium pressure in viscous flow. • Results allow implementing the state-to-state approach for viscous flow simulations. - Abstract: Viscous gas flows with vibrational relaxation and chemical reactions in the state-to-state approach are analyzed. A modified Chapman–Enskog method is used for the determination of chemical reaction and vibrational transition rates and non-equilibrium pressure. Constitutive equations depend on the thermodynamic forces: velocity divergence and chemical reaction/transition affinity. As an application, N 2 flow with vibrational relaxation across a shock wave is investigated. Two distinct processes occur behind the shock: for small values of the distance the affinity is large and vibrational relaxation is in its initial stage; for large distances the affinity is small and the chemical reaction is in its final stage. The affinity contributes more to the transition rate than the velocity divergence and the effect of these two contributions are more important for small distances from the shock front. For the non-equilibrium pressure, the term associated with the bulk viscosity increases by a small amount the hydrostatic pressure

  4. Chemical reaction rates and non-equilibrium pressure of reacting gas mixtures in the state-to-state approach

    Energy Technology Data Exchange (ETDEWEB)

    Kustova, Elena V., E-mail: e.kustova@spbu.ru [Department of Mathematics and Mechanics, Saint Petersburg State University, 198504 Universitetskiy pr. 28, Saint Petersburg (Russian Federation); Kremer, Gilberto M., E-mail: kremer@fisica.ufpr.br [Departamento de Física, Universidade Federal do Paraná, Caixa Postal 19044, 81531-980 Curitiba (Brazil)

    2014-12-05

    Highlights: • State-to-state approach for coupled vibrational relaxation and chemical reactions. • Self-consistent model for rates of non-equilibrium reactions and energy transitions. • In viscous flows mass action law is violated. • Cross coupling between reaction rates and non-equilibrium pressure in viscous flow. • Results allow implementing the state-to-state approach for viscous flow simulations. - Abstract: Viscous gas flows with vibrational relaxation and chemical reactions in the state-to-state approach are analyzed. A modified Chapman–Enskog method is used for the determination of chemical reaction and vibrational transition rates and non-equilibrium pressure. Constitutive equations depend on the thermodynamic forces: velocity divergence and chemical reaction/transition affinity. As an application, N{sub 2} flow with vibrational relaxation across a shock wave is investigated. Two distinct processes occur behind the shock: for small values of the distance the affinity is large and vibrational relaxation is in its initial stage; for large distances the affinity is small and the chemical reaction is in its final stage. The affinity contributes more to the transition rate than the velocity divergence and the effect of these two contributions are more important for small distances from the shock front. For the non-equilibrium pressure, the term associated with the bulk viscosity increases by a small amount the hydrostatic pressure.

  5. Fluxes of chemically reactive species inferred from mean concentration measurements

    NARCIS (Netherlands)

    Galmarini, S.; Vilà-Guerau De Arellano, J.; Duyzer, J.H.

    1997-01-01

    A method is presented for the calculation of the fluxes of chemically reactive species on the basis of routine measurements of meteorological variables and chemical species. The method takes explicity into account the influence of chemical reactions on the fluxes of the species. As a demonstration

  6. A novel class of chemicals that react with abasic sites in DNA and specifically kill B cell cancers.

    Directory of Open Access Journals (Sweden)

    Shanqiao Wei

    Full Text Available Most B cell cancers overexpress the enzyme activation-induced deaminase at high levels and this enzyme converts cytosines in DNA to uracil. The constitutive expression of this enzyme in these cells greatly increases the uracil content of their genomes. We show here that these genomes also contain high levels of abasic sites presumably created during the repair of uracils through base-excision repair. We further show that three alkoxyamines with an alkyne functional group covalently link to abasic sites in DNA and kill immortalized cell lines created from B cell lymphomas, but not other cancers. They also do not kill normal B cells. Treatment of cancer cells with one of these chemicals causes strand breaks, and the sensitivity of the cells to this chemical depends on the ability of the cells to go through the S phase. However, other alkoxyamines that also link to abasic sites- but lack the alkyne functionality- do not kill cells from B cell lymphomas. This shows that the ability of alkoxyamines to covalently link to abasic sites is insufficient for their cytotoxicity and that the alkyne functionality may play a role in it. These chemicals violate the commonly accepted bioorthogonality of alkynes and are attractive prototypes for anti-B cell cancer agents.

  7. CHEMICAL COMPOSITION OF CAATINGA POTENTIAL FORAGES SPECIES

    Directory of Open Access Journals (Sweden)

    Dynara Layza de Souza da Silva

    2015-12-01

    Full Text Available Chemical composition of some potential forages species, natives from Caatinga region, were evaluated. Samples of Macroptilium heterophyllum, Stylosanthes humilis, Rhynchosia mínima, Desmodium tortuosum Sw. Dc, Merremia aegyptia, Mimosa tenuiflora Wild, Bauhinia cheilantha and as well Macroptilium lathyroides, Caesalpinia pyramidalis and Mimosa tenuiflora hays were collected in Rio Grande do Norte Stated, during 2011 rainy season. The analyses: dry matter (DM, crude protein (CP mineral matter (MM ether extract  (EE neutral detergent fiber (NDF, acid detergent fiber (ADF, lignin (LIG, insoluble neutral detergent nitrogen, (INDN insoluble acid detergent nitrogen, (ADIN, total phenol (TF and total tannin (TT were done at Embrapa Caprinos e Ovinos in Ceará State. Plants analyzed, as expected, for tropical species, exhibited high level of cell wall constituents, high lignifications rate and revealed substantial presence of anti nutritional compounds. However, regardless of this data, the main problem, for grazing animals, is due to its xerophytes characteristics. Most of the shrubs and trees are deciduous, losing its leaves during the dry season. In addition, herbaceous presents a very rapid lifetime cycle, germinating and senescing during the brief wet season.

  8. Effects of heat and mass transfer on unsteady boundary layer flow of a chemical reacting Casson fluid

    Science.gov (United States)

    Khan, Kashif Ali; Butt, Asma Rashid; Raza, Nauman

    2018-03-01

    In this study, an endeavor is to observe the unsteady two-dimensional boundary layer flow with heat and mass transfer behavior of Casson fluid past a stretching sheet in presence of wall mass transfer by ignoring the effects of viscous dissipation. Chemical reaction of linear order is also invoked here. Similarity transformation have been applied to reduce the governing equations of momentum, energy and mass into non-linear ordinary differential equations; then Homotopy analysis method (HAM) is applied to solve these equations. Numerical work is done carefully with a well-known software MATHEMATICA for the examination of non-dimensional velocity, temperature, and concentration profiles, and then results are presented graphically. The skin friction (viscous drag), local Nusselt number (rate of heat transfer) and Sherwood number (rate of mass transfer) are discussed and presented in tabular form for several factors which are monitoring the flow model.

  9. Experimental determination of the bulk temperature values in a nonisothermal flow of the chemically reacting nitrogen tetroxide

    International Nuclear Information System (INIS)

    Devojno, A.N.; Kolykhan, L.I.; Stepanenko, V.N.; Tverkovkin, B.E.; Uyutov, G.I.

    1975-01-01

    The technique and results of an experimental determination of mean mass temperatures of a cooled chemically active nitrogen tetroxide flowing in a circular tube under turbulent flow conditions are considered. The parameters range as follows: pressure-from 8.10 5 to 16.10 5 H/m 2 , flow temperature-from 140 deg to 550 deg C, Reynolds number-from 3,1.1g 5 , flow velocity-from 3.5 to 45 m/s. The gas temperature along the length of the test tube is measured with movable probe with a mixer and thermocouple in a stainless steel capillary 2mm in dia and the wall 0,2 mm thick. The mean-square deviations of measured temperature values from the predicted ones are about -0.9 and +1.8%. The obtained data show the predicted temperature values to be somewhat lower than the measured ones, the difference increasing with the distance to the test tube outlet. It may be explained by both unaccounted systematic experimental errors and errors in calculating the mean mass flow temperatures. The investigation described confirms the possibility of an experimental determination of the mean gas temperature along the cooled channel length by mean mass of a movable mixer with a single thermocouple

  10. Comparative toxicity of ten organic chemicals to four earthworm species

    Energy Technology Data Exchange (ETDEWEB)

    Neuhauser, E.F.; Durkin, P.R.; Malecki, M.R.; Anatra, M.

    1986-01-01

    Ten organic chemicals were tested for toxicity to four earthworm species: Allolobophora tuberculata, Eisenia fetida, Eudrilus eugeniae and Perionyx excavatus, using the European Economic Community's (EEC) earthworm artificial soil and contact testing procedure. The phenols were the most toxic chemicals tested, followed by the amine, substituted benzenes, halogenated aliphatic hydrocarbon, polycyclic aromatic hydrocarbon and phthalate as the least toxic chemical tested. Correlations among species within each type of test for a given chemical were extremely high, suggesting that the selection of earthworm test species does not markedly affect the assessment of a chemical's toxicity. The correlation between the two tests was low for all test species. The contact test LC50 for a given chemical cannot be directly correlated to an artificial soil test LC50 for the same earthworm species.

  11. Transuranic chemical species in groundwater. Final report

    International Nuclear Information System (INIS)

    Cowan, C.E.; Jenne, E.A.; Robertson, D.E.; Nelson, D.M.; Abel, K.H.

    1985-02-01

    For the past several years, staff at Pacific Northwest Laboratory (PNL) have been studying the mobility of actinides, primarily plutonium, in the groundwater of a low-level disposal site. This research has provided valuable insights into the behavior of plutonium in the groundwater. Based on the analytical data and geochemical modeling, it appears that the plutonium that enters the trench, primarily in the higher oxidation states, Pu(V,VI), is rapidly reduced as the water migrates through the highly reducing sediments of the trench and is removed from the water by adsorption of the reduced plutonium, Pu(III,IV), onto the sediments. The Pu(V,VI) also appears to be reduced in the groundwater, although not as rapidly as in the trench sediments, and removed by adsorption. Because of the redox reduction that occurs during the migration of the groundwater, the system is not at redox equilibrium. Based on the discrepancies between the calculated and analytically determined redox distribution and charge-form speciation, the thermodynamic data bases for plutonium appear either to be missing or to contain incorrect thermodynamic data for several aqueous plutonium species, including the carbonate and organic complexes of plutonium. Further research is required to determine the kinetics of plutonium oxidation/reduction reactions in natural groundwater systems and to determine thermodynamic data for carbonate and organic complexes of plutonium. 52 references, 1 figure, 6 tables

  12. Chemical cues mediate species recognition in field crickets

    Directory of Open Access Journals (Sweden)

    Frances eTyler

    2015-05-01

    Full Text Available Cuticular hydrocarbons (CHCs are important in mate choice in many insects, and may be used for species recognition if CHC profiles differ between potentially hybridizing species. In the sibling field cricket species Gryllus campestris and G. bimaculatus, females of G. bimaculatus are tolerant towards G. campestris males and can mate with them. However, G. campestris females are highly aggressive towards heterospecific G. bimaculatus males, and matings between them never happen. We examined whether cricket females might use CHCs to determine the species identity of their potential mates. We firstly analyzed the cuticular chemical profile by gas chromatography and mass spectrometry to assess the potential of CHCs to be used for species recognition in these crickets. We then manipulated females’ ability to detect chemical cues by carrying out chemical ablation of the antennae, and measured changes in aggressive responses to heterospecific males. We show that there are significant interspecies differences in CHC expression for both sexes, and that females with chemically ablated antennae reduce aggressive behavior towards heterospecific males. Our findings support the prediction that cuticular semiochemicals can play a key role in reproductive isolation between closely related insect species.

  13. Chemical Characteristics of Six Woody Species for Alley Cropping

    Directory of Open Access Journals (Sweden)

    Mosango, M.

    1999-01-01

    Full Text Available Leaves of six woody species (Leguminosae for alley cropping have been chemically analysed in order to evaluate their potentiality in the restoration of soil fertility. These species are : Acacia mangium, Cajanus cajan, Flemingia grahamiana, F. macrophylla, Leucaena leucocephala and Sesbania sesban. Nitrogen, carbon, cellulose, hemicellulose, lignin, active fraction and ash contents were determined as well as C/N and L/N ratios. AH these species appear to be rich in N and C. Fiber contents (cellulose, hemicellulose and lignin are globally low but variable from one species to another. C/N and L/N ratios are globally low. Among these species, Leucaena leucocephala and Senna spectabilis show the lowest C/N and LIN ratios. Such low values of C/N and L/N are normally found in species with rapid decomposition of organic matter.

  14. Quantification of the removal of chemical species by snow

    Energy Technology Data Exchange (ETDEWEB)

    Schwikowski, M.; Baltensperger, U.; Bruetsch, S.; Keil, R.; Gaeggeler, H.W. [Paul Scherrer Inst. (PSI), Villigen (Switzerland); Poulida, O. [Frederick Research Center, Nicosia (Cyprus)

    1997-09-01

    In order to quantify the scavenging of chemical species in mixed phase clouds, in-cloud field experiments were conducted in October and November 1993 at the high-alpine research station Jungfraujoch. On the average, air to snow transfer fractions were rather low with the highest value of 0.5 for nitrate, thus, most of the air borne chemical mass remained in the air parcel after precipitation. (author) 1 fig., 4 refs.

  15. A model for reaction rates in turbulent reacting flows

    Science.gov (United States)

    Chinitz, W.; Evans, J. S.

    1984-01-01

    To account for the turbulent temperature and species-concentration fluctuations, a model is presented on the effects of chemical reaction rates in computer analyses of turbulent reacting flows. The model results in two parameters which multiply the terms in the reaction-rate equations. For these two parameters, graphs are presented as functions of the mean values and intensity of the turbulent fluctuations of the temperature and species concentrations. These graphs will facilitate incorporation of the model into existing computer programs which describe turbulent reacting flows. When the model was used in a two-dimensional parabolic-flow computer code to predict the behavior of an experimental, supersonic hydrogen jet burning in air, some improvement in agreement with the experimental data was obtained in the far field in the region near the jet centerline. Recommendations are included for further improvement of the model and for additional comparisons with experimental data.

  16. A computer model for one-dimensional mass and energy transport in and around chemically reacting particles, including complex gas-phase chemistry, multicomponent molecular diffusion, surface evaporation, and heterogeneous reaction

    Science.gov (United States)

    Cho, S. Y.; Yetter, R. A.; Dryer, F. L.

    1992-01-01

    Various chemically reacting flow problems highlighting chemical and physical fundamentals rather than flow geometry are presently investigated by means of a comprehensive mathematical model that incorporates multicomponent molecular diffusion, complex chemistry, and heterogeneous processes, in the interest of obtaining sensitivity-related information. The sensitivity equations were decoupled from those of the model, and then integrated one time-step behind the integration of the model equations, and analytical Jacobian matrices were applied to improve the accuracy of sensitivity coefficients that are calculated together with model solutions.

  17. An exact solution on unsteady MHD free convection chemically reacting silver nanofluid flow past an exponentially accelerated vertical plate through porous medium

    Science.gov (United States)

    Kumaresan, E.; Vijaya Kumar, A. G.; Rushi Kumar, B.

    2017-11-01

    This article studies, an exact solution of unsteady MHD free convection boundary-layer flow of a silver nanofluid past an exponentially accelerated moving vertical plate through aporous medium in the presence of thermal radiation, transverse applied amagnetic field, radiation absorption and Heat generation or absorption with chemical reaction are investigated theoretically. We consider nanofluids contain spherical shaped nanoparticle of silverwith a nanoparticle volume concentration range smaller than or equal to 0.04. This phenomenon is modeled in the form of partial differential equations with initial boundary conditions. Some suitable dimensional variables are introduced. The corresponding dimensionless equations with boundary conditions are solved by using Laplace transform technique. The exact solutions for velocity, energy, and species are obtained, also the corresponding numerical values of nanofluid velocity, temperature and concentration profiles are represented graphically. The expressions for skin friction coefficient, the rate of heat transfer and mass transfer are derived. The present study finds applications involving heat transfer, enhancement of thermal conductivity and other applications like transportation, industrial cooling applications, heating buildings and reducing pollution, energy applications and solar absorption. The effect of heat transfer is found to be more pronounced in a silver-water nanofluid than in the other nanofluids.

  18. Direct numerical simulation of turbulent reacting flows

    Energy Technology Data Exchange (ETDEWEB)

    Chen, J.H. [Sandia National Laboratories, Livermore, CA (United States)

    1993-12-01

    The development of turbulent combustion models that reflect some of the most important characteristics of turbulent reacting flows requires knowledge about the behavior of key quantities in well defined combustion regimes. In turbulent flames, the coupling between the turbulence and the chemistry is so strong in certain regimes that is is very difficult to isolate the role played by one individual phenomenon. Direct numerical simulation (DNS) is an extremely useful tool to study in detail the turbulence-chemistry interactions in certain well defined regimes. Globally, non-premixed flames are controlled by two limiting cases: the fast chemistry limit, where the turbulent fluctuations. In between these two limits, finite-rate chemical effects are important and the turbulence interacts strongly with the chemical processes. This regime is important because industrial burners operate in regimes in which, locally the flame undergoes extinction, or is at least in some nonequilibrium condition. Furthermore, these nonequilibrium conditions strongly influence the production of pollutants. To quantify the finite-rate chemistry effect, direct numerical simulations are performed to study the interaction between an initially laminar non-premixed flame and a three-dimensional field of homogeneous isotropic decaying turbulence. Emphasis is placed on the dynamics of extinction and on transient effects on the fine scale mixing process. Differential molecular diffusion among species is also examined with this approach, both for nonreacting and reacting situations. To address the problem of large-scale mixing and to examine the effects of mean shear, efforts are underway to perform large eddy simulations of round three-dimensional jets.

  19. Reproductive Impacts of Endocrine-Disrupting Chemicals on Wildlife Species: Implications for Conservation of Endangered Species.

    Science.gov (United States)

    Tubbs, Christopher W; McDonough, Caitlin E

    2018-02-15

    Wildlife have proven valuable to our understanding of the potential effects of endocrine-disrupting chemicals (EDCs) on human health by contributing considerably to our understanding of the mechanisms and consequences of EDC exposure. But the threats EDCs present to populations of wildlife species themselves are significant, particularly for endangered species whose existence is vulnerable to any reproductive perturbation. However, few studies address the threats EDCs pose to endangered species owing to challenges associated with their study. Here, we highlight those barriers and review the available literature concerning EDC effects on endangered species. Drawing from other investigations into nonthreatened wildlife species, we highlight opportunities for new approaches to advance our understanding and potentially mitigate the effects of EDCs on endangered species to enhance their fertility.

  20. Chemical thermodynamics of iodine species in the HTGR fuel particle

    International Nuclear Information System (INIS)

    Lindemer, T.B.

    1982-09-01

    The iodine-containing species in an intact fuel particle in the high-temperature gas-cooled reactor (HTGR) have been calculated. Assumptions include: (1) attainment of chemical thermodynamic equilibrium among all species in the open porosity of the particle, primarily in the buffer layer; and (2) fission-product concentrations in proportion to their yields. The primary gaseous species is calculated to be cesium iodide; in carbide-containing fuels, gaseous barium iodide may exhibit equivalent pressures. The condensed iodine-containing phase is usually cesium iodide, but in carbide-containing fuels, barium iodide may be stable instead. Absorption of elemental iodine on the carbon in the particle appears to be less than or equal to 10 -4 μg I/g C. The fission-product-spectra excess of cesium over iodine would generally be adsorbed on the carbon, but may form Cs 2 MoO 4 under some circumstances

  1. The REACT Project

    DEFF Research Database (Denmark)

    Bloch, Paul; Blystad, Astrid; Byskov, Jens

    decisions; and the provision of leadership and the enforcement of conditions. REACT - "REsponse to ACcountable priority setting for Trust in health systems" is an EU-funded five-year intervention study, which started in 2006 testing the application and effects of the AFR approach in one district each...... selected disease and programme interventions and services, within general care and on health systems management. Efforts to improve health sector performance have not yet been satisfactory, and adequate and sustainable improvements in health outcomes have not been shown. Priority setting in health systems...... improvements to health systems performance discussed....

  2. Criterion for selection of quasi-equilibrium and quasi-frozen flows of chemically reacting mixture N2O4 reversible 2NO2reversible 2NO+O2 with heat isobaric supply (removal)

    International Nuclear Information System (INIS)

    Kostik, G.Eh.; Shiryaeva, N.M.

    1979-01-01

    Is suggested the criterion of quasi-equilibrium and quasi-frozen flows with isobaric heat supply (removal), including the basic external factors, which affect on the kinetics of chemical process. This criterion is the complex [g/Fq], where g is the coolant rate, F is the channel cross-section, q is the heat flow. Estimated formulae for quasi-equilibrium [g/Fq]sub(e) and quasi-frozen [g/Fq]sub(f) flows are obtained. The states of deviation from equilibrium and frozen conditions in linear region are considered, are listed graphical dependences lg[g/Fq]sub(e), lg[g/Fq]sub(el), lg[g/Fq]sub(f), lg[g/Eq]sub(fl), as functions of equilibrium parameter Tsub(e), pressure and frozen coordinate of epsilonsub(2f) reaction. This graphs give the possibility to estimate rapidly and obviously the flow character of chemically reacting coolant

  3. Chemical species of plutonium in Hanford radioactive tank waste

    International Nuclear Information System (INIS)

    Barney, G.S.

    1997-01-01

    Large quantities of radioactive wastes have been generated at the Hanford Site over its operating life. The wastes with the highest activities are stored underground in 177 large (mostly one million gallon volume) concrete tanks with steel liners. The wastes contain processing chemicals, cladding chemicals, fission products, and actinides that were neutralized to a basic pH before addition to the tanks to prevent corrosion of the steel liners. Because the mission of the Hanford Site was to provide plutonium for defense purposes, the amount of plutonium lost to the wastes was relatively small. The best estimate of the amount of plutonium lost to all the waste tanks is about 500 kg. Given uncertainties in the measurements, some estimates are as high as 1,000 kg (Roetman et al. 1994). The wastes generally consist of (1) a sludge layer generated by precipitation of dissolved metals from aqueous wastes solutions during neutralization with sodium hydroxide, (2) a salt cake layer formed by crystallization of salts after evaporation of the supernate solution, and (3) an aqueous supernate solution that exists as a separate layer or as liquid contained in cavities between sludge or salt cake particles. The identity of chemical species of plutonium in these wastes will allow a better understanding of the behavior of the plutonium during storage in tanks, retrieval of the wastes, and processing of the wastes. Plutonium chemistry in the wastes is important to criticality and environmental concerns, and in processing the wastes for final disposal. Plutonium has been found to exist mainly in the sludge layers of the tanks along with other precipitated metal hydrous oxides. This is expected due to its low solubility in basic aqueous solutions. Tank supernate solutions do not contain high concentrations of plutonium even though some tanks contain high concentrations of complexing agents. The solutions also contain significant concentrations of hydroxide which competes with other

  4. Adomian decomposition method for Hall and ion-slip effects on mixed convection flow of a chemically reacting Newtonian fluid between parallel plates with heat generation/absorption

    Directory of Open Access Journals (Sweden)

    Ch.Ram Reddy

    2017-12-01

    Full Text Available This paper analyzes the heat and mass transfer characteristics on mixed convective fully developed flow in an electrically conducting Newtonian fluid between vertical parallel plates. The chemical reaction, heat generation, Hall and ion-slip effects are taken into consideration. By using similarity transformations the nonlinear governing equations are reduced into dimensionless form and hence solved using Adomian decomposition method (ADM. The influence of magnetic parameter, Hall parameter, ion-slip parameter, chemical reaction parameter, and heat generation/absorption parameter on non-dimensional velocities, temperature and concentration profiles are exhibited graphically. In addition, the numerical data for skin friction, heat and mass transfer rates are shown in tabular form.

  5. Some aspects of theory and mathematics of thermal runaway in reacting chemical systems that may be relevant to critical behaviour in confined plasmas

    International Nuclear Information System (INIS)

    Ball, R. The

    1999-01-01

    The concept of an endothermally stabilised chemical reactor as an enthalpy coupled thermokinetic system is introduced, and given precise mathematical expression in the form of a four-dimensional dynamical system. Criteria are defined for which the system is free of all kinds of thermal misbehaviour. This important dynamical result defines bounds for a large region of the parameter space within which the reactor may be operated safely. The formalism of singularity theory is extended to bifurcation surfaces in a studio of multiplicity and stability in the CSTR problem

  6. Calorimetry of non-reacting systems

    CERN Document Server

    McCullough, John P

    2013-01-01

    Experimental Thermodynamics, Volume 1: Calorimetry of Non-Reacting Systems covers the heat capacity determinations for chemical substances in the solid, liquid, solution, and vapor states, at temperatures ranging from near the absolute zero to the highest at which calorimetry is feasible.This book is divided into 14 chapters. The first four chapters provide background information and general principles applicable to all types of calorimetry of non-reacting systems. The remaining 10 chapters deal with specific types of calorimetry. Most of the types of calorimetry treated are developed over a c

  7. Chemically reacting fluid flow induced by an exponentially accelerated infinite vertical plate in a magnetic field and variable temperature via LTT and FEM

    Directory of Open Access Journals (Sweden)

    Srinivasa Raju R.

    2016-01-01

    Full Text Available In this research paper, we found both numerical and analytical solutions for the effect of chemical reaction on unsteady, incompressible, viscous fluid flow past an exponentially accelerated vertical plate with heat absorption and variable temperature in a magnetic field. The flow problem is governed by a system of coupled non-linear partial differential equations with suitable boundary conditions. We have solved the governing equations by an efficient, accurate, powerful finite element method (FEM as well as Laplace transform technique (LTT. The evaluation of the numerical results are performed and graphical results for the velocity, temperature and concentration profiles within the boundary layer are discussed. Also, the expressions for the skin-friction, Nusselt number and the Sherwood number coefficients have been derived and discussed through graphs and tabular forms for different values of the governing parameters.

  8. Improving chemical species tomography of turbulent flows using covariance estimation.

    Science.gov (United States)

    Grauer, Samuel J; Hadwin, Paul J; Daun, Kyle J

    2017-05-01

    Chemical species tomography (CST) experiments can be divided into limited-data and full-rank cases. Both require solving ill-posed inverse problems, and thus the measurement data must be supplemented with prior information to carry out reconstructions. The Bayesian framework formalizes the role of additive information, expressed as the mean and covariance of a joint-normal prior probability density function. We present techniques for estimating the spatial covariance of a flow under limited-data and full-rank conditions. Our results show that incorporating a covariance estimate into CST reconstruction via a Bayesian prior increases the accuracy of instantaneous estimates. Improvements are especially dramatic in real-time limited-data CST, which is directly applicable to many industrially relevant experiments.

  9. MICROMORPHOLOGICAL AND CHEMICAL ASPECTS OF SOME LICHENIZED FUNGI SPECIES

    Directory of Open Access Journals (Sweden)

    PÎNDARU DIANA-MIHAELA

    2012-12-01

    Full Text Available At present, lichenized fungi are used in biomonitoring studies of air quality, being good receptors in the climate change. This paper aims to investigate surface micromorphology of Xanthoria parietina and Phaeophyscia orbicularis species (Lecanoromycetes, Ascomycota. The study also includes the investigation of selected chemical parameters as pH and conductivity of the lichenized fungi samples collected from various locations in the Iaşi County (Romania. Measurements of the pH provide information on the degree of pollution in the location of interest. Bark trees pH was also investigated in order to see if our matrix substrate influences the pH of the interest lichenized fungi samples.

  10. Chemical composition of some wild peanut species (Arachis L.) seeds.

    Science.gov (United States)

    Grosso, N R; Nepote, V; Guzmán, C A

    2000-03-01

    Oil, protein, ash, and carbohydrate contents, iodine value, and fatty acid and sterol compositions were studied in seeds of Arachis trinitensis, A. chiquitana, A. kempff-mercadoi, A. diogoi, A. benensis, A. appressipila, A. valida, A. kretschmeri, A. helodes, A. kuhlmannii, A. williamsii, A. sylvestris, A. matiensis, A. pintoi, A. hoehnei, A. villosa, and A. stenosperma. Oil content was greatest in A.stenosperma (mean value = 51.8%). The protein level was higher in A. sylvestris (30.1%) and A. villosa (29.5%). Mean value of oleic acid varied between 30.6% (A. matiensis) and 46.8% (Arachis villosa), and linoleic acid oscillated between 34.1% (A. villosa) and 47.4% (A. appressipila). The better oleic-to-linoleic (O/L) ratio was exhibited by A. villosa (1.38). Some species showed higher concentration of behenic acid. The greatest level of this fatty acid was found in A. matiensis (6.2%). Iodine value was lower in A. valida (99.2). The sterol composition in the different peanut species showed higher concentration of beta-sitosterol (mean values oscillated between 55.7 and 60.2%) followed by campesterol (12.4-16. 5%), stigmasterol (9.7-13.3%), and Delta(5)-avenasterol (9.7-13.4%). The chemical quality and stability of oils (iodine value and O/L ratio) from wild peanut studied in this work are not better than those of cultivated peanut.

  11. Thermodynamic properties of chemical species of waste radionuclides

    International Nuclear Information System (INIS)

    Silva, R.J.; Nitsche, H.

    1984-01-01

    The object of the experimental program at Lawrence Berkeley Laboratory is to identify gaps or conflicts in thermodynamic data on the solubilities of compounds and on the formation of solution complexes of waste radionuclides needed for the reliable prediction of solution concentrations. It involves laboratory measurements necessary to (1) generate specific new data, where none exists, in order to demonstrate the importance of a particular solution species, compound or solution parameter (e.g., temperature, Eh) and to (2) resolve conflicts in existing thermodynamic data on important species or compounds. The measurement of the solubility of AmOHCO 3 in 0.1 M NaClO 4 at 25 0 C and 1 atmosphere pressure has been completed. From the experimental data, an average solubility product quotient, Qsp, was evaluated for the reaction, AmOHCO 3 (S) + 2H + = Am 3+ + HCO 3 - + H 2 O. The logarithm of Qsp was calculated to be 2.74 +/- .17. Speciation calculations, using this new data plus reported data on the solubility of Am(OH) 3 and the hydrolysis and carbonate complexation of Am 3+ , indicate that the presence of carbonate can have a substantial effect on the nature of compounds and solution species formed by americium in ground waters. Since actinides in a given oxidation state tend to exhibit similar chemical properties, this result should apply to other actinides in the trivalent state. Thus, the effect of carbonate on the solubilities and complexation of trivalent actinides should be included in any predictive modelling studies required for licensing. 27 references, 4 figures, 5 tables

  12. Comparing bee species responses to chemical mixtures: Common response patterns?

    Directory of Open Access Journals (Sweden)

    Alex Robinson

    Full Text Available Pollinators in agricultural landscapes can be exposed to mixtures of pesticides and environmental pollutants. Existing mixture toxicity modelling approaches, such as the models of concentration addition and independent action and the mechanistic DEBtox framework have been previously shown as valuable tools for understanding and ultimately predicting joint toxicity. Here we apply these mixture models to investigate the potential to interpret the effects of semi-chronic binary mixture exposure for three bee species: Apis mellifera, Bombus terrestris and Osmia bicornis within potentiation and mixture toxicity experiments. In the potentiation studies, the effect of the insecticide dimethoate with added propiconazole fungicide and neonicotinoid insecticide clothianidin with added tau-fluvalinate pyrethroid acaricide showed no difference in toxicity compared to the single chemical alone. Clothianidin toxicity showed a small scale, but temporally conserved increase in exposure conducted in the presence of propiconazole, particularly for B. terrestris and O. bicornis, the latter showing a near three-fold increase in clothianidin toxicity in the presence of propiconazole. In the mixture toxicity studies, the dominant response patterns were of additivity, however, binary mixtures of clothianidin and dimethoate in A. mellifera, B. terrestris and male O. bicornis there was evidence of a predominant antagonistic interaction. Given the ubiquitous nature of exposures to multiple chemicals, there is an urgent need to consider mixture effects in pollinator risk assessments. Our analyses suggest that current models, particularly those that utilise time-series data, such as DEBtox, can be used to identify additivity as the dominant response pattern and also those examples of interactions, even when small-scale, that may need to be taken into account during risk assessment.

  13. Numerical Simulation of Chemically Reacting Flows

    Science.gov (United States)

    2015-09-03

    flam in three spa ructured gri olves couple ed nature pr described in e LRR3D a Jacobian (no e rate of Ne t way, so th may be nonz local connec ion...the M formulation. omputationa prediction, mostly over mportant ad taggered gri . With all t pproach th 2012, the M ncluding fla mes with ad ate

  14. Mathematical aspects of reacting and diffusing systems

    CERN Document Server

    Fife, Paul C

    1979-01-01

    Modeling and analyzing the dynamics of chemical mixtures by means of differ- tial equations is one of the prime concerns of chemical engineering theorists. These equations often take the form of systems of nonlinear parabolic partial d- ferential equations, or reaction-diffusion equations, when there is diffusion of chemical substances involved. A good overview of this endeavor can be had by re- ing the two volumes by R. Aris (1975), who himself was one of the main contributors to the theory. Enthusiasm for the models developed has been shared by parts of the mathematical community, and these models have, in fact, provided motivation for some beautiful mathematical results. There are analogies between chemical reactors and certain biological systems. One such analogy is rather obvious: a single living organism is a dynamic structure built of molecules and ions, many of which react and diffuse. Other analogies are less obvious; for example, the electric potential of a membrane can diffuse like a chemical, and ...

  15. Recent advances in ultrafast-laser-based spectroscopy and imaging for reacting plasmas and flames

    Science.gov (United States)

    Patnaik, Anil K.; Adamovich, Igor; Gord, James R.; Roy, Sukesh

    2017-10-01

    Reacting flows and plasmas are prevalent in a wide array of systems involving defense, commercial, space, energy, medical, and consumer products. Understanding the complex physical and chemical processes involving reacting flows and plasmas requires measurements of key parameters, such as temperature, pressure, electric field, velocity, and number densities of chemical species. Time-resolved measurements of key chemical species and temperature are required to determine kinetics related to the chemical reactions and transient phenomena. Laser-based, noninvasive linear and nonlinear spectroscopic approaches have proved to be very valuable in providing key insights into the physico-chemical processes governing reacting flows and plasmas as well as validating numerical models. The advent of kilohertz rate amplified femtosecond lasers has expanded the multidimensional imaging of key atomic species such as H, O, and N in a significant way, providing unprecedented insight into preferential diffusion and production of these species under chemical reactions or electric-field driven processes. These lasers not only provide 2D imaging of chemical species but have the ability to perform measurements free of various interferences. Moreover, these lasers allow 1D and 2D temperature-field measurements, which were quite unimaginable only a few years ago. The rapid growth of the ultrafast-laser-based spectroscopic measurements has been fueled by the need to achieve the following when measurements are performed in reacting flows and plasmas. They are: (1) interference-free measurements (collision broadening, photolytic dissociation, Stark broadening, etc), (2) time-resolved single-shot measurements at a rate of 1-10 kHz, (3) spatially-resolved measurements, (4) higher dimensionality (line, planar, or volumetric), and (5) simultaneous detection of multiple species. The overarching goal of this article is to review the current state-of-the-art ultrafast-laser-based spectroscopic

  16. Expanding the species and chemical diversity of Penicillium section Cinnamopurpurea

    DEFF Research Database (Denmark)

    Peterson, Stephen W.; Jurjević, Željko; Frisvad, Jens Christian

    2015-01-01

    isolates and sequenced. Two species in section Cinnamopurpurea are self-compatible sexual species, but the asexual species had polymorphic loci suggestive of sexual reproduction and variation in conidium size suggestive of ploidy level differences typical of heterothallism. Accordingly we use genealogical...... concordance analysis, a technique valid only in heterothallic organisms, for putatively asexual species. Seven new species were revealed in the analysis and are described here. Extrolite analysis showed that two of the new species, P. colei and P. monsserratidens produce the mycotoxin citreoviridin that has...

  17. Expanding the species and chemical diversity of Penicillium section Cinnamopurpurea.

    Directory of Open Access Journals (Sweden)

    Stephen W Peterson

    Full Text Available A set of isolates very similar to or potentially conspecific with an unidentified Penicillium isolate NRRL 735, was assembled using a BLAST search of ITS similarity among described (GenBank and undescribed Penicillium isolates in our laboratories. DNA was amplified from six loci of the assembled isolates and sequenced. Two species in section Cinnamopurpurea are self-compatible sexual species, but the asexual species had polymorphic loci suggestive of sexual reproduction and variation in conidium size suggestive of ploidy level differences typical of heterothallism. Accordingly we use genealogical concordance analysis, a technique valid only in heterothallic organisms, for putatively asexual species. Seven new species were revealed in the analysis and are described here. Extrolite analysis showed that two of the new species, P. colei and P. monsserratidens produce the mycotoxin citreoviridin that has demonstrated pharmacological activity against human lung tumors. These isolates could provide leads in pharmaceutical research.

  18. Novel view on predicting acute toxicity: Decomposing toxicity data in species vulnerability and chemical potency.

    NARCIS (Netherlands)

    Jager, D.T.; Posthuma, L.; Zwart, D.D.; van de Meent, D.

    2007-01-01

    Chemical risk assessment usually applies empirical methods to predict toxicant effects on different species. We propose a more mechanism-oriented approach, and introduce a method to decompose toxicity data in a contribution from the chemical (potency) and from the exposed species (vulnerability). We

  19. Chemical analysis of bioactive substances in seven siberian Saussurea species

    Science.gov (United States)

    Avdeeva, Elena; Reshetov, Yaroslav; Shurupova, Margarita; Zibareva, Larisa; Borisova, Evgeniia; Belousov, Mikhail

    2017-11-01

    Main groups of biologically active substances of seven siberian Saussurea species (S. controversa DC., S. latifolia Ledeb., S. parviflora (Poir.) DC., S. frolowii Ledeb, S. amara (L.) DC., S. salicifolia (L.) DC. and S. daurica Adams) have been studied using paper, thin-layer, performance liquid chromatography, IR spectroscopy, spectrophotometry and mass spectrometry with inductively coupled plasma. Siberian Saussurea species have a rich elemental composition and contain a variety of phenolic compounds, amino acids, polysaccharides. The majority of polysaccharides are accumulated by S. controversa, S. salicifolia and S. frolowii. These plants contain a significant amount of calcium that may be a species characteristic. All plants contain quercetin and its glycosides, in some species luteolin, kaempferol, glycosides of apigenin and myricetin were revealed. Phenolic acids with predominant content of caffeic, chlorogenic and cinnamic acids were found in all the species. The maximum amount of phenolic acids and flavonoids was determined in the grass of S. latifolia, S. controversa and S. daurica. Characteristic absorption bands of lactone carbonyl of sesquiterpenoids in IR spectrum found in S. latifolia, S. controversa, S. daurica, S. amara and S. salicifolia. HPLC / UV analysis showed that peaks with absorption maxima of 242-246 nm due to the presence of α,β-unsaturated ketone group in the structure of ecdysteroids were found in S. salicifolia, S. controversa, S. daurica and S. latifolia.

  20. Chemical equilibrium of ablation materials including condensed species

    Science.gov (United States)

    Stroud, C. W.; Brinkley, K. L.

    1975-01-01

    Equilibrium is determined by finding chemical composition with minimum free energy. Method of steepest descent is applied to quadratic representation of free-energy surface. Solution is initiated by selecting arbitrary set of mole fractions, from which point on free-energy surface is computed.

  1. Wood Chemical Composition in Species of Cactaceae: The Relationship between Lignification and Stem Morphology

    Science.gov (United States)

    Canché-Escamilla, Gonzalo; Soto-Hernández, Marcos

    2015-01-01

    In Cactaceae, wood anatomy is related to stem morphology in terms of the conferred support. In species of cacti with dimorphic wood, a unique process occurs in which the cambium stops producing wide-band tracheids (WBTs) and produces fibers; this is associated with the aging of individuals and increases in size. Stem support and lignification have only been studied in fibrous tree-like species, and studies in species with WBTs or dimorphic wood are lacking. In this study, we approach this process with a chemical focus, emphasizing the role of wood lignification. We hypothesized that the degree of wood lignification in Cactaceae increases with height of the species and that its chemical composition varies with wood anatomy. To test this, we studied the chemical composition (cellulose, hemicellulose, and lignin content) in 13 species (2 WBTs wood, 3 dimorphic, and 8 fibrous) with contrasting growth forms. We also analyzed lignification in dimorphic and fibrous species to determine the chemical features of WBTs and fibers and their relationship with stem support. The lignin contents were characterized by Fourier transform infrared spectroscopy and high performance liquid chromatography. We found that 11 species have a higher percentage (>35%) of lignin in their wood than other angiosperms or gymnosperms. The lignin chemical composition in fibrous species is similar to that of other dicots, but it is markedly heterogeneous in non-fibrous species where WBTs are abundant. The lignification in WBTs is associated with the resistance to high water pressure within cells rather than the contribution to mechanical support. Dimorphic wood species are usually richer in syringyl lignin, and tree-like species with lignified rays have more guaiacyl lignin. The results suggest that wood anatomy and lignin distribution play an important role in the chemical composition of wood, and further research is needed at the cellular level. PMID:25880223

  2. Wood chemical composition in species of Cactaceae: the relationship between lignification and stem morphology.

    Directory of Open Access Journals (Sweden)

    Jorge Reyes-Rivera

    Full Text Available In Cactaceae, wood anatomy is related to stem morphology in terms of the conferred support. In species of cacti with dimorphic wood, a unique process occurs in which the cambium stops producing wide-band tracheids (WBTs and produces fibers; this is associated with the aging of individuals and increases in size. Stem support and lignification have only been studied in fibrous tree-like species, and studies in species with WBTs or dimorphic wood are lacking. In this study, we approach this process with a chemical focus, emphasizing the role of wood lignification. We hypothesized that the degree of wood lignification in Cactaceae increases with height of the species and that its chemical composition varies with wood anatomy. To test this, we studied the chemical composition (cellulose, hemicellulose, and lignin content in 13 species (2 WBTs wood, 3 dimorphic, and 8 fibrous with contrasting growth forms. We also analyzed lignification in dimorphic and fibrous species to determine the chemical features of WBTs and fibers and their relationship with stem support. The lignin contents were characterized by Fourier transform infrared spectroscopy and high performance liquid chromatography. We found that 11 species have a higher percentage (>35% of lignin in their wood than other angiosperms or gymnosperms. The lignin chemical composition in fibrous species is similar to that of other dicots, but it is markedly heterogeneous in non-fibrous species where WBTs are abundant. The lignification in WBTs is associated with the resistance to high water pressure within cells rather than the contribution to mechanical support. Dimorphic wood species are usually richer in syringyl lignin, and tree-like species with lignified rays have more guaiacyl lignin. The results suggest that wood anatomy and lignin distribution play an important role in the chemical composition of wood, and further research is needed at the cellular level.

  3. Wood chemical composition in species of Cactaceae: the relationship between lignification and stem morphology.

    Science.gov (United States)

    Reyes-Rivera, Jorge; Canché-Escamilla, Gonzalo; Soto-Hernández, Marcos; Terrazas, Teresa

    2015-01-01

    In Cactaceae, wood anatomy is related to stem morphology in terms of the conferred support. In species of cacti with dimorphic wood, a unique process occurs in which the cambium stops producing wide-band tracheids (WBTs) and produces fibers; this is associated with the aging of individuals and increases in size. Stem support and lignification have only been studied in fibrous tree-like species, and studies in species with WBTs or dimorphic wood are lacking. In this study, we approach this process with a chemical focus, emphasizing the role of wood lignification. We hypothesized that the degree of wood lignification in Cactaceae increases with height of the species and that its chemical composition varies with wood anatomy. To test this, we studied the chemical composition (cellulose, hemicellulose, and lignin content) in 13 species (2 WBTs wood, 3 dimorphic, and 8 fibrous) with contrasting growth forms. We also analyzed lignification in dimorphic and fibrous species to determine the chemical features of WBTs and fibers and their relationship with stem support. The lignin contents were characterized by Fourier transform infrared spectroscopy and high performance liquid chromatography. We found that 11 species have a higher percentage (>35%) of lignin in their wood than other angiosperms or gymnosperms. The lignin chemical composition in fibrous species is similar to that of other dicots, but it is markedly heterogeneous in non-fibrous species where WBTs are abundant. The lignification in WBTs is associated with the resistance to high water pressure within cells rather than the contribution to mechanical support. Dimorphic wood species are usually richer in syringyl lignin, and tree-like species with lignified rays have more guaiacyl lignin. The results suggest that wood anatomy and lignin distribution play an important role in the chemical composition of wood, and further research is needed at the cellular level.

  4. Chemical score of different protein sources to four Macrobrachium species

    OpenAIRE

    Montoya-Martínez, Cynthia; Nolasco-Soria, Héctor; Carrillo-Farnés, Olimpia; Civera-Cerecedo, Roberto; Álvarez-González, Carlos; Vega-Villasante, Fernando

    2016-01-01

    Food production for aquaculture requires finding other protein sources or ingredients as potential alternatives in the formulation of aquaculture feeds, due to the shortage and high price of protein sources that are most commonly used. The aim of this analysis was to evaluate the relationship between the essential amino acids in 13 types of proteins available in the market with the essential amino acids found in the muscle of four of the most important farmed prawn species of the genus Macrob...

  5. Molecular Simulation of Reacting Systems; TOPICAL

    International Nuclear Information System (INIS)

    THOMPSON, AIDAN P.

    2002-01-01

    The final report for a Laboratory Directed Research and Development project entitled, Molecular Simulation of Reacting Systems is presented. It describes efforts to incorporate chemical reaction events into the LAMMPS massively parallel molecular dynamics code. This was accomplished using a scheme in which several classes of reactions are allowed to occur in a probabilistic fashion at specified times during the MD simulation. Three classes of reaction were implemented: addition, chain transfer and scission. A fully parallel implementation was achieved using a checkerboarding scheme, which avoids conflicts due to reactions occurring on neighboring processors. The observed chemical evolution is independent of the number of processors used. The code was applied to two test applications: irreversible linear polymerization and thermal degradation chemistry

  6. Chemical and pharmacological investigation of Acacia and Santalum species

    DEFF Research Database (Denmark)

    Knudsen, Diana Jæger

    compounds from plants still have a huge potential for investigation for medicinal properties as possible drug leads. Humans have a long history of using plant medicine in treatments and indigenous cultures are a remarkable source for immense knowledge about plants and the uses of them - knowledge that has...... often only exists amongst members of communities or groups of the land where it has arisen. In this PhD project the three Australian plant species Acacia ligulata A.Cunn. ex Benth, Santalum spicatum (R.Br.) A.DC and Santalum lanceolatum R.Br were investigated for their bioactivity and chemistry...

  7. SeqAPASS: Predicting chemical susceptibility to threatened/endangered species

    Science.gov (United States)

    Conservation of a molecular target across species can be used as a line-of-evidence to predict the likelihood of chemical susceptibility. The web-based Sequence Alignment to Predict Across Species Susceptibility (SeqAPASS; https://seqapass.epa.gov/seqapass/) application was devel...

  8. The electrochemical generation of useful chemical species from lunar materials

    Science.gov (United States)

    Tsai, Kan J.; Kuchynka, Daniel J.; Sammells, Anthony F.

    1989-01-01

    The current status of work on an electrochemical technology for the simultaneous generation of oxygen and lithium from a Li2O containing molten salt (Li2O-LiCl-LiF) is discussed. The electrochemical cell utilizes an oxygen vacancy conducting solid electrolyte, yttria-stabilized zirconia, to effect separation between the oxygen evolving and lithium reduction half-cell reactions. The cell, which operates at 700 to 800 C, possesses rapid electrode kinetics at the lithium-alloy electrode with exchange current density values being greater than 60 mA/sq cm, showing high reversibility for this reaction. When used in the electrolytic mode, lithium produced at the negative electrode would be continuously removed from the cell for later use (under lunar conditions) as an easily storable reducting agent (compared to H2) for the chemical refining of lunar ores via the general reaction: 2Li + MO yields Li2O + M where MO represents a lunar ore. Emphasis to this time has been on the simulated lunar ore ilmenite (FeTiO3), which we have found becomes chemically reduced by Li at 432 C. Furthermore, both Fe2O3 and TiO2 have been reduced by Li to give the corresponding metal. This electrochemical approach provides a convenient route for producing metals under lunar conditions and oxygen for the continuous maintenance of human habitats on the Moon's surface. Because of the high reversibility of this electrochemical system, it has also formed the basis for the lithium-oxygen secondary battery. This secondary lithium-oxygen battery system posses the highest theoretical energy density yet investigated.

  9. Speciation and internal dosimetry: from chemical species to dosimetric models

    International Nuclear Information System (INIS)

    Paquet, F.; Frelon, S.; Cote, G.; Madic, C.

    2004-01-01

    Speciation studies refer to the distribution of species in a particular sample or matrix. These studies are necessary to improve the description, understanding and prediction of trace element kinetics and toxicity. In case of internal contamination with radionuclides, speciation studies could help to improve both the biokinetic and dosimetric models for radionuclides. There are different methods to approach the speciation of radionuclide in a biological system, depending on the degree of accuracy needed and the level of uncertainties accepted. Among them, computer modelling and experimental determination are complementary approaches. This paper describes what is known about speciation of actinides in blood, GI-tract, liver and skeleton and of their consequences in terms of internal dosimetry. The conclusion is that such studies provide very valuable data and should be targeted in the future on some specific tissues and biomolecules. (authors)

  10. DNA fingerprinting, biological and chemical investigation of certain Yucca species.

    Science.gov (United States)

    El Hawary, Seham; El Sayed, Abeer; Helmy, Maged W; El Naggar, El Moataz Bellah; Marzouk, Hanan S; Bassam, Samar M

    2018-01-05

    Yucca aloifolia, Y. aloifolia variegata, Y. elephantipes and Y. filamentosa were investigated. DNA sequencing was performed for the four plants and a genomic DNA fingerprint was obtained and provided. The cytotoxic activities against four human cancer cell lines were investigated. The ethanolic extracts of leaves of Y. aloifolia variegata prevailed, especially against liver cancer HepG-2 and breast cancer MCF-7. In vivo assessment of hepatoprotective activity in rats also revealed the hepatoprotective potential of the ethanolic extracts of the four plants against CCl 4 - induced rats' liver damage. Qualitative and quantitative analysis of the flavonoid and phenolic content of the promising species was performed using HPLC. The analysis identified and quantified 18 flavonoids and 19 phenolic acids in the different fractions of Y. aloifolia variegata, among which the major flavonoids were hesperidin and kaemp-3-(2-p-coumaroyl) glucose and the major phenolic acids were gallic acid and protocatechuic acid.

  11. Kaempferitrin from Uncaria guianensis (Rubiaceae) and its potential as a chemical marker for the species

    International Nuclear Information System (INIS)

    Valente, Ligia M.M.; Liechocki, Sally; Barboza, Rodolfo S.; Paixao, Djavan da; Bizarri, Carlos H.B.; Almeida, M. Beatriz S.; Benevides, Paulo J.C.; Siani, Antonio C.; Magalhaes, Alvicler

    2009-01-01

    Uncaria tomentosa (Willd.) DC. and U. guianensis (Aubl.) Gmel., known as cat's claw, are large woody vines native to the Amazonian and Central American rain forests. The species contain, in different proportions, indole and oxindole alkaloids, triterpenoid glycosides, sterols and proanthocyanidins. U. tomentosa can be chemically identified by its oxindole alkaloid profile and content, whereas U. guianensis has no satisfactorily established chemical markers. This work describes, for the first time, the isolation of kaempferol-3,7-O-(a)-dirhamnoside (kaempferitrin) in Uncaria species. Screening for this compound in leaves, stems or bark of both species through TLC and HPLC-DAD-MS showed the presence of kaempferitrin only in the leaves and stems of U. guianensis, at a ratio almost thirty six times greater in the leaves than in the stems. These results reveal the selectivity of U. guianensis to produce this bioactive flavonoid glycoside, and suggest this compound as a potential chemical marker for the species.(author)

  12. Chemical similarity and local community assembly in the species rich tropical genus Piper.

    Science.gov (United States)

    Salazar, Diego; Jaramillo, M Alejandra; Marquis, Robert J

    2016-11-01

    Community ecologists have strived to find mechanisms that mediate the assembly of natural communities. Recent evidence suggests that natural enemies could play an important role in the assembly of hyper-diverse tropical plant systems. Classic ecological theory predicts that in order for coexistence to occur, species differences must be maximized across biologically important niche dimensions. For plant-herbivore interactions, it has been recently suggested that, within a particular community, plant species that maximize the difference in chemical defense profiles compared to neighboring taxa will have a relative competitive advantage. Here we tested the hypothesis that plant chemical diversity can affect local community composition in the hyper-diverse genus Piper at a lowland wet forest location in Costa Rica. We first characterized the chemical composition of 27 of the most locally abundant species of Piper. We then tested whether species with different chemical compositions were more likely to coexist. Finally, we assessed the degree to which Piper phylogenetic relationships are related to differences in secondary chemical composition and community assembly. We found that, on average, co-occurring species were more likely to differ in chemical composition than expected by chance. Contrary to expectations, there was no phylogenetic signal for overall secondary chemical composition. In addition we found that species in local communities were, on average, more phylogenetically closely related than expected by chance, suggesting that functional traits other than those measured here also influence local assembly. We propose that selection by herbivores for divergent chemistries between closely related species facilitates the coexistence of a high diversity of congeneric taxa via apparent competition. © 2016 by the Ecological Society of America.

  13. Chemical composition and antioxidant activity of certain Morus species

    Science.gov (United States)

    Imran, Mohammad; Khan, Hamayun; Shah, Mohibullah; Khan, Rasool; Khan, Faridullah

    2010-01-01

    In the present work, the fruits of four Morus species, namely Morus alba (white mulberry), Morus nigra (black mulberry), Morus laevigata (large white fruit), and Morus laevigata (large black fruit), were analyzed for proximate composition, essential minerals, and antioxidant potentials. For this purpose, the ripe fruits were collected from the northern regions of Pakistan. The major nutritional components (moisture, ash, lipids, proteins, fibres, carbohydrates, and total sugar) were found to be in the suitable range along with good computed energy. Total dry weight, pH, and titratable acidity (percent citric acid) were (17.60±1.94)–(21.97±2.34) mg/100 g, (3.20±0.07)–(4.78±0.15), and (0.84±0.40)%–(2.00±0.08)%, respectively. Low riboflavin (vitamin B2) and niacin (vitamin B3) contents were recorded in all the fruits, while ascorbic acid (vitamin C) was in the range from (15.20±1.25) to (17.03±1.71) mg/100 g fresh weight (FW). The mulberry fruits were rich with regard to the total phenol and alkaloid contents, having values of (880±7.20)–(1650±12.25) mg/100 g FW and (390±.22)–(660±5.25) mg/100 g FW, respectively. Sufficient quantities of essential macro-(K, Ca, Mg, and Na) and micro-(Fe, Zn, and Ni) elements were found in all the fruits. K was the predominant element with concentration ranging from (1270±9.36) to (1731±11.50) mg/100 g, while Ca, Na, and Mg contents were (440±3.21)–(576±7.37), (260±3.86)–(280±3.50), and (24±3.51)–(360±4.20) mg/100 g, respectivly. The decreasing order of micro-minerals was Fe>Zn>Ni. The radical scavenging activity of methanolic extract of fruits was concentration-dependent and showed a correlation with total phenolic constituents of the respective fruits. Based on the results obtained, mulberry fruits were found to serve as a potential source of food diet and natural antioxidants. PMID:21121077

  14. Chemical generation of volatile species of copper – Optimization, efficiency and investigation of volatile species nature

    Czech Academy of Sciences Publication Activity Database

    Šoukal, Jakub; Benada, Oldřich; Matoušek, Tomáš; Dědina, Jiří; Musil, Stanislav

    2017-01-01

    Roč. 977, JUL (2017), s. 10-19 ISSN 0003-2670 Institutional support: RVO:68081715 ; RVO:61388971 Keywords : generation of volatile species * copper * analytical atomic spectrometry Subject RIV: CB - Analytical Chemistry, Separation; EE - Microbiology, Virology (MBU-M) OBOR OECD: Analytical chemistry; Microbiology (MBU-M) Impact factor: 4.950, year: 2016

  15. Chemical, Bioactive, and Antioxidant Potential of Twenty Wild Culinary Mushroom Species

    Science.gov (United States)

    Sharma, S. K.; Gautam, N.

    2015-01-01

    The chemical, bioactive, and antioxidant potential of twenty wild culinary mushroom species being consumed by the people of northern Himalayan regions has been evaluated for the first time in the present study. Nutrients analyzed include protein, crude fat, fibres, carbohydrates, and monosaccharides. Besides, preliminary study on the detection of toxic compounds was done on these species. Bioactive compounds evaluated are fatty acids, amino acids, tocopherol content, carotenoids (β-carotene, lycopene), flavonoids, ascorbic acid, and anthocyanidins. Fruitbodies extract of all the species was tested for different types of antioxidant assays. Although differences were observed in the net values of individual species all the species were found to be rich in protein, and carbohydrates and low in fat. Glucose was found to be the major monosaccharide. Predominance of UFA (65–70%) over SFA (30–35%) was observed in all the species with considerable amounts of other bioactive compounds. All the species showed higher effectiveness for antioxidant capacities. PMID:26199938

  16. Chemical, Bioactive, and Antioxidant Potential of Twenty Wild Culinary Mushroom Species

    Directory of Open Access Journals (Sweden)

    S. K. Sharma

    2015-01-01

    Full Text Available The chemical, bioactive, and antioxidant potential of twenty wild culinary mushroom species being consumed by the people of northern Himalayan regions has been evaluated for the first time in the present study. Nutrients analyzed include protein, crude fat, fibres, carbohydrates, and monosaccharides. Besides, preliminary study on the detection of toxic compounds was done on these species. Bioactive compounds evaluated are fatty acids, amino acids, tocopherol content, carotenoids (β-carotene, lycopene, flavonoids, ascorbic acid, and anthocyanidins. Fruitbodies extract of all the species was tested for different types of antioxidant assays. Although differences were observed in the net values of individual species all the species were found to be rich in protein, and carbohydrates and low in fat. Glucose was found to be the major monosaccharide. Predominance of UFA (65–70% over SFA (30–35% was observed in all the species with considerable amounts of other bioactive compounds. All the species showed higher effectiveness for antioxidant capacities.

  17. Chemical, Bioactive, and Antioxidant Potential of Twenty Wild Culinary Mushroom Species.

    Science.gov (United States)

    Sharma, S K; Gautam, N

    2015-01-01

    The chemical, bioactive, and antioxidant potential of twenty wild culinary mushroom species being consumed by the people of northern Himalayan regions has been evaluated for the first time in the present study. Nutrients analyzed include protein, crude fat, fibres, carbohydrates, and monosaccharides. Besides, preliminary study on the detection of toxic compounds was done on these species. Bioactive compounds evaluated are fatty acids, amino acids, tocopherol content, carotenoids (β-carotene, lycopene), flavonoids, ascorbic acid, and anthocyanidins. Fruitbodies extract of all the species was tested for different types of antioxidant assays. Although differences were observed in the net values of individual species all the species were found to be rich in protein, and carbohydrates and low in fat. Glucose was found to be the major monosaccharide. Predominance of UFA (65-70%) over SFA (30-35%) was observed in all the species with considerable amounts of other bioactive compounds. All the species showed higher effectiveness for antioxidant capacities.

  18. Multiphase reacting flows modelling and simulation

    CERN Document Server

    Marchisio, Daniele L

    2007-01-01

    The papers in this book describe the most widely applicable modeling approaches and are organized in six groups covering from fundamentals to relevant applications. In the first part, some fundamentals of multiphase turbulent reacting flows are covered. In particular the introduction focuses on basic notions of turbulence theory in single-phase and multi-phase systems as well as on the interaction between turbulence and chemistry. In the second part, models for the physical and chemical processes involved are discussed. Among other things, particular emphasis is given to turbulence modeling strategies for multiphase flows based on the kinetic theory for granular flows. Next, the different numerical methods based on Lagrangian and/or Eulerian schemes are presented. In particular the most popular numerical approaches of computational fluid dynamics codes are described (i.e., Direct Numerical Simulation, Large Eddy Simulation, and Reynolds-Averaged Navier-Stokes approach). The book will cover particle-based meth...

  19. Various chemical strategies to deceive ants in three Arhopala species (lepidoptera: Lycaenidae exploiting Macaranga myrmecophytes.

    Directory of Open Access Journals (Sweden)

    Yoko Inui

    Full Text Available Macaranga myrmecophytes (ant-plants are generally well protected from herbivore attacks by their symbiotic ants (plant-ants. However, larvae of Arhopala (Lepidoptera: Lycaenidae species survive and develop on specific Macaranga ant-plant species without being attacked by the plant-ants of their host species. We hypothesized that Arhopala larvae chemically mimic or camouflage themselves with the ants on their host plant so that the larvae are accepted by the plant-ant species of their host. Chemical analyses of cuticular hydrocarbons showed that chemical congruency varied among Arhopala species; A. dajagaka matched well the host plant-ants, A. amphimuta did not match, and unexpectedly, A. zylda lacked hydrocarbons. Behaviorally, the larvae and dummies coated with cuticular chemicals of A. dajagaka were well attended by the plant-ants, especially by those of the host. A. amphimuta was often attacked by all plant-ants except for the host plant-ants toward the larvae, and those of A. zylda were ignored by all plant-ants. Our results suggested that conspicuous variations exist in the chemical strategies used by the myrmecophilous butterflies that allow them to avoid ant attack and be accepted by the plant-ant colonies.

  20. Chemical investigation on wood tree species in a temperate forest, east-northern Romania

    Directory of Open Access Journals (Sweden)

    Teaca, C. A.

    2007-02-01

    Full Text Available A quantitative evaluation of wood chemical components for some tree species in a forest area from east-northern Romania is presented here, through a comparative study from 1964 to 2000. Investigation upon the wood tree-rings in a Quercus robur L. tree species, as a dominant species, as regards its chemical composition and structure of the natural polymer constituents - cellulose and lignin - was also performed through chemical methods to separate the main wood components, FT-IR spectroscopy, and thermogravimetry. Having in view the impact of climate and external factors (such as pollutant depositions, some possible correlations between wood chemical composition and its further use can be made. The FT-IR spectra give evidence of differences in the frequency domains of 3400-2900 cm-1 and 1730-1640 cm-1, due to some interactions between the chemical groups (OH, C=O. The crystallinity index of cellulose presents variations in the oak wood tree-rings. Thermogravimetry analyses show different behaviour of cellulose at thermal decomposition, as a function of radial growth and tree’s height. A preliminary chemical investigation of oak wood sawdust shows a relatively high content of mineral elements (ash, compared with a previous study performed in 1964, fact that may indicate an intense drying process of the oak tree, a general phenomenon present in European forests for this species.

  1. Can species-specific prey responses to chemical cues explain prey susceptibility to predation?

    Science.gov (United States)

    Šmejkal, Marek; Ricard, Daniel; Sajdlová, Zuzana; Čech, Martin; Vejřík, Lukáš; Blabolil, Petr; Vejříková, Ivana; Prchalová, Marie; Vašek, Mojmír; Souza, Allan T; Brönmark, Christer; Peterka, Jiří

    2018-05-01

    The perception of danger represents an essential ability of prey for gaining an informational advantage over their natural enemies. Especially in complex environments or at night, animals strongly rely on chemoreception to avoid predators. The ability to recognize danger by chemical cues and subsequent adaptive responses to predation threats should generally increase prey survival. Recent findings suggest that European catfish ( Silurus glanis ) introduction induce changes in fish community and we tested whether the direction of change can be attributed to differences in chemical cue perception. We tested behavioral response to chemical cues using three species of freshwater fish common in European water: rudd ( Scardinius erythrophthalmus ), roach ( Rutilus rutilus ), and perch ( Perca fluviatilis ). Further, we conducted a prey selectivity experiment to evaluate the prey preferences of the European catfish. Roach exhibited the strongest reaction to chemical cues, rudd decreased use of refuge and perch did not alter any behavior in the experiment. These findings suggest that chemical cue perception might be behind community data change and we encourage collecting more community data of tested prey species before and after European catfish introduction to test the hypothesis. We conclude that used prey species can be used as a model species to verify whether chemical cue perception enhances prey survival.

  2. Computing multi-species chemical equilibrium with an algorithm based on the reaction extents

    DEFF Research Database (Denmark)

    Paz-Garcia, Juan Manuel; Johannesson, Björn; Ottosen, Lisbeth M.

    2013-01-01

    -negative constrains. The residual function, representing the distance to the equilibrium, is defined from the chemical potential (or Gibbs energy) of the chemical system. Local minimums are potentially avoided by the prioritization of the aqueous reactions with respect to the heterogeneous reactions. The formation......A mathematical model for the solution of a set of chemical equilibrium equations in a multi-species and multiphase chemical system is described. The computer-aid solution of model is achieved by means of a Newton-Raphson method enhanced with a line-search scheme, which deals with the non...... and release of gas bubbles is taken into account in the model, limiting the concentration of volatile aqueous species to a maximum value, given by the gas solubility constant.The reaction extents are used as state variables for the numerical method. As a result, the accepted solution satisfies the charge...

  3. Chemical review and studies related to species from the genus Tynanthus (Bignoniaceae

    Directory of Open Access Journals (Sweden)

    Fernanda Colombi Cansian

    2015-09-01

    Full Text Available Species from the Bignoniaceae Family, including the genus Tynanthus, are very prevalent in the tropical Americas, with specimens found in a large part of the Brazilian territory. These plants are commonly used in traditional medicine for several purposes, and some studies have described their chemical structure, in addition to other reports related to some species from this genus. This review aimed to gather information from published works concerning species of the genus Tynanthus, as well as to detect flaws in research related to these plants, which may have great biological and pharmaceutical importance. Also, this review points out some common chemical characteristics of these species, providing information that may help new researchers to improve their knowledge about these plants.

  4. Exudate Chemical Profiles Derived from Lespedeza and Other Tallgrass Prairie Plant Species

    Science.gov (United States)

    2017-05-01

    Chemical Profiles Derived from Lespedeza and Other Tall- grass Prairie Plant Species. ERDC TN-17-1. Vicksburg, MS: U.S. Army Engineer Re- search and...200-1-52. Washington, DC: U.S. Army Corps of Engineers Headquarters, Civil Works. https://www.wbdg.org/ffc/army-coe/public-works-technical-bulletins...ERDC TN-17-1 May 2017 Approved for public release; distribution is unlimited. Exudate Chemical Profiles Derived from Lespedeza and Other

  5. Toward systems metabolic engineering of Aspergillus and Pichia species for the production of chemicals and biofuels

    DEFF Research Database (Denmark)

    Caspeta, Luis; Nielsen, Jens

    2013-01-01

    trends in systems biology of Aspergillus and Pichia species, highlighting the relevance of these developments for systems metabolic engineering of these organisms for the production of hydrolytic enzymes, biofuels and chemicals from biomass. Metabolic engineering is moving from traditional methods...... for the production of hydrolytic enzymes, biofuels and chemicals from biomass. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim....

  6. Chemical, Bioactive, and Antioxidant Potential of Twenty Wild Culinary Mushroom Species

    OpenAIRE

    Sharma, S. K.; Gautam, N.

    2015-01-01

    The chemical, bioactive, and antioxidant potential of twenty wild culinary mushroom species being consumed by the people of northern Himalayan regions has been evaluated for the first time in the present study. Nutrients analyzed include protein, crude fat, fibres, carbohydrates, and monosaccharides. Besides, preliminary study on the detection of toxic compounds was done on these species. Bioactive compounds evaluated are fatty acids, amino acids, tocopherol content, carotenoids (β-carotene, ...

  7. Chemical composition, mineral content and amino acid and lipid profiles in bones from various fish species.

    Science.gov (United States)

    Toppe, Jogeir; Albrektsen, Sissel; Hope, Britt; Aksnes, Anders

    2007-03-01

    The chemical composition, content of minerals and the profiles of amino acids and fatty acids were analyzed in fish bones from eight different species of fish. Fish bones varied significantly in chemical composition. The main difference was lipid content ranging from 23 g/kg in cod (Gadus morhua) to 509 g/kg in mackerel (Scomber scombrus). In general fatty fish species showed higher lipid levels in the bones compared to lean fish species. Similarly, lower levels of protein and ash were observed in bones from fatty fish species. Protein levels differed from 363 g/kg lipid free dry matter (dm) to 568 g/kg lipid free dm with a concomitant inverse difference in ash content. Ash to protein ratio differed from 0.78 to 1.71 with the lowest level in fish that naturally have highest swimming and physical activity. Saithe (Pollachius virens) and salmon (Salmo salar) were found to be significantly different in the levels of lipid, protein and ash, and ash/protein ratio in the bones. Only small differences were observed in the level of amino acids although species specific differences were observed. The levels of Ca and P in lipid free fish bones were about the same in all species analyzed. Fatty acid profile differed in relation to total lipid levels in the fish bones, but some minor differences between fish species were observed.

  8. Systematic Approach to Calculate the Concentration of Chemical Species in Multi-Equilibrium Problems

    Science.gov (United States)

    Baeza-Baeza, Juan Jose; Garcia-Alvarez-Coque, Maria Celia

    2011-01-01

    A general systematic approach is proposed for the numerical calculation of multi-equilibrium problems. The approach involves several steps: (i) the establishment of balances involving the chemical species in solution (e.g., mass balances, charge balance, and stoichiometric balance for the reaction products), (ii) the selection of the unknowns (the…

  9. Chemical profiles of body surfaces and nests from six Bornean stingless bee species.

    Science.gov (United States)

    Leonhardt, Sara Diana; Blüthgen, Nico; Schmitt, Thomas

    2011-01-01

    Stingless bees (Apidae: Meliponini) are the most diverse group of Apid bees and represent common pollinators in tropical ecosystems. Like honeybees they live in large eusocial colonies and rely on complex chemical recognition and communication systems. In contrast to honeybees, their ecology and especially their chemical ecology have received only little attention, particularly in the Old World. We previously have analyzed the chemical profiles of six paleotropical stingless bee species from Borneo and revealed the presence of species-specific cuticular terpenes- an environmentally derived compound class so far unique among social insects. Here, we compared the bees' surface profiles to the chemistry of their nest material. Terpenes, alkanes, and alkenes were the dominant compound groups on both body surfaces and nest material. However, bee profiles and nests strongly differed in their chemical composition. Body surfaces thus did not merely mirror nests, rendering a passive compound transfer from nests to bees unlikely. The difference between nests and bees was particularly pronounced when all resin-derived compounds (terpenes) were excluded and only genetically determined compounds were considered. When terpenes were included, bee profiles and nest material still differed, because whole groups of terpenes (e.g., sesquiterpenes) were found in nest material of some species, but missing in their chemical profile, indicating that bees are able to influence the terpene composition both in their nests and on their surfaces.

  10. Mobility and Attenuation Dynamics of Potentially Toxic Chemical Species at an Abandoned Copper Mine Tailings Dump

    Directory of Open Access Journals (Sweden)

    Wilson Mugera Gitari

    2018-02-01

    Full Text Available Large volumes of disposed mine tailings abound in several regions of South Africa, as a consequence of unregulated, unsustainable long years of mining activities. Tailings dumps occupy a large volume of valuable land, and present a potential risk for aquatic systems, through leaching of potentially toxic chemical species. This paper reports on the evaluation of the geochemical processes controlling the mobility of potentially toxic chemical species within the tailings profile, and their potential risk with regard to surface and groundwater systems. Combination of X-ray fluorescence (XRF, X-ray diffraction (XRD, and scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS techniques, show that the tailing profiles are uniform, weakly altered, and vary slightly with depth in both physical and geochemical properties, as well as mineralogical composition. Mineralogical analysis showed the following order of abundance: quartz > epidote > chlorite > muscovite > calcite > hematite within the tailings profiles. The neutralization of the dominant alumino-silicate minerals and the absence of sulfidic minerals, have produced medium alkaline pH conditions (7.97–8.37 at all depths and low concentrations of dissolved Cu (20.21–47.9 µg/L, Zn (0.88–1.80 µg/L, Pb (0.27–0.34 µg/L, and SO42− (15.71–55.94 mg/L in the tailings profile leachates. The relative percentage leach for the potentially toxic chemical species was low in the aqueous phase (Ni 0.081%, Cu 0.006%, and Zn 0.05%. This indicates that the transport load of potentially toxic chemical species from tailings to the aqueous phase is very low. The precipitation of secondary hematite has an important known ability to trap and attenuate the mobility of potentially toxic chemical species (Cu, Zn, and Pb by adsorption on the surface area. Geochemical modelling MINTEQA2 showed that the tailings leachates were below saturation regarding oxyhydroxide minerals, but oversaturated with Cu

  11. Physico-chemical thresholds in the distribution of fish species among French lakes

    Directory of Open Access Journals (Sweden)

    Roubeix Vincent

    2017-01-01

    Full Text Available The management of lakes requires the definition of physico-chemical thresholds to be used for ecosystem preservation or restoration. According to the European Water Framework Directive, the limits between physico-chemical quality classes must be set consistently with biological quality elements. One way to do this consists in analyzing the response of aquatic communities to environmental gradients across monitoring sites and in identifying ecological community thresholds, i.e. zones in the gradients where the species turnover is the highest. In this study, fish data from 196 lakes in France were considered to derive ecological thresholds using the multivariate method of gradient forest. The analysis was performed on 25 species and 36 environmental parameters. The results revealed the highest importance of maximal water temperature in the distribution of fish species. Other important parameters included geographical factors, dissolved organic carbon concentration and water transparency, while nutrients appeared to have low influence. In spite of the diversity of species responses to the gradients, community thresholds were detected in the gradients of the most important physico-chemical parameters and of total phosphorus and nitrate concentrations as well. The thresholds identified in such macroecological study may highlight new patterns of species natural distribution and improve niche characterization. Moreover, when factors that may be influenced by human activities are involved, the thresholds could be used to set environmental standards for lake preservation.

  12. USE OF AMAZONIAN SPECIES FOR AGING DISTILLED BEVERAGES: PHYSICAL AND CHEMICAL WOOD ANALYSIS

    Directory of Open Access Journals (Sweden)

    Jonnys Paz Castro

    2015-06-01

    Full Text Available The process of storing liquor in wooden barrels is a practice that aims to improve the sensory characteristics, such as color, aroma and flavor, of the beverage. The quality of the liquor stored in these barrels depends on wood characteristics such as density, permeability, chemical composition, anatomy, besides the wood heat treatment used to fabricate the barrels. Brazil has a great diversity of forests, mainly in the north, in the Amazon. This region is home to thousands of tree species, but is limited to the use of only a few native species to store liquors. The objective of this study was to determine some of the physical and chemical characteristics for four Amazon wood species. The results obtained in this study will be compared with others from woods that are traditionally used for liquor storage. The species studied were angelim-pedra (Hymenolobium petraeum Ducke cumarurana (Dipteryx polyphylla (Huber Ducke, jatobá (Hymenaea courbaril L. and louro-vermelho (Nectandra rubra (Mez CK Allen. The trees were collected from Precious Woods Amazon Company forest management area, in Silves, Amazonas. Analyzes such as: concentration of extractives, lignin amount, percentage of minerals (ash and tannin content, density, elemental analysis (CHNS-O and thermal analysis were done. It was observed that the chemical composition (lignin, holocellulose and elemental analysis (percentage of C, H, N and O of the woods have significant differences. The jatobá wood presented higher tannin content, and in the thermal analysis, was that which had the lowest mass loss.

  13. Kaempferitrin from Uncaria guianensis (Rubiaceae) and its potential as a chemical marker for the species

    Energy Technology Data Exchange (ETDEWEB)

    Valente, Ligia M.M.; Liechocki, Sally; Barboza, Rodolfo S.; Paixao, Djavan da [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Inst. de Quimica], e-mail: valente@iq.ufrj.br; Bizarri, Carlos H.B.; Almeida, M. Beatriz S.; Benevides, Paulo J.C.; Siani, Antonio C. [Fundacao Oswaldo Cruz (FIOCRUZ), Rio de Janeiro, RJ (Brazil). Inst. de Tecnologia em Farmacos; Magalhaes, Alvicler [Universidade Estadual de Campinas (UNICAMP), SP (Brazil). Inst. de Quimica

    2009-07-01

    Uncaria tomentosa (Willd.) DC. and U. guianensis (Aubl.) Gmel., known as cat's claw, are large woody vines native to the Amazonian and Central American rain forests. The species contain, in different proportions, indole and oxindole alkaloids, triterpenoid glycosides, sterols and proanthocyanidins. U. tomentosa can be chemically identified by its oxindole alkaloid profile and content, whereas U. guianensis has no satisfactorily established chemical markers. This work describes, for the first time, the isolation of kaempferol-3,7-O-(a)-dirhamnoside (kaempferitrin) in Uncaria species. Screening for this compound in leaves, stems or bark of both species through TLC and HPLC-DAD-MS showed the presence of kaempferitrin only in the leaves and stems of U. guianensis, at a ratio almost thirty six times greater in the leaves than in the stems. These results reveal the selectivity of U. guianensis to produce this bioactive flavonoid glycoside, and suggest this compound as a potential chemical marker for the species.(author)

  14. Arbuscular mycorrhizal fungi alter above- and below-ground chemical defense expression differentially among Asclepias species

    Science.gov (United States)

    Vannette, Rachel L.; Hunter, Mark D.; Rasmann, Sergio

    2013-01-01

    Below-ground (BG) symbionts of plants can have substantial influence on plant growth and nutrition. Recent work demonstrates that mycorrhizal fungi can affect plant resistance to herbivory and the performance of above- (AG) and BG herbivores. Although these examples emerge from diverse systems, it is unclear if plant species that express similar defensive traits respond similarly to fungal colonization, but comparative work may inform this question. To examine the effects of arbuscular mycorrhizal fungi (AMF) on the expression of chemical resistance, we inoculated 8 species of Asclepias (milkweed)—which all produce toxic cardenolides—with a community of AMF. We quantified plant biomass, foliar and root cardenolide concentration and composition, and assessed evidence for a growth-defense tradeoff in the presence and absence of AMF. As expected, total foliar and root cardenolide concentration varied among milkweed species. Importantly, the effect of mycorrhizal fungi on total foliar cardenolide concentration also varied among milkweed species, with foliar cardenolides increasing or decreasing, depending on the plant species. We detected a phylogenetic signal to this variation; AMF fungi reduced foliar cardenolide concentrations to a greater extent in the clade including A. curassavica than in the clade including A. syriaca. Moreover, AMF inoculation shifted the composition of cardenolides in AG and BG plant tissues in a species-specific fashion. Mycorrhizal inoculation changed the relative distribution of cardenolides between root and shoot tissue in a species-specific fashion, but did not affect cardenolide diversity or polarity. Finally, a tradeoff between plant growth and defense in non-mycorrhizal plants was mitigated completely by AMF inoculation. Overall, we conclude that the effects of AMF inoculation on the expression of chemical resistance can vary among congeneric plant species, and ameliorate tradeoffs between growth and defense. PMID:24065971

  15. Arbuscular mycorrhizal fungi alter above- and below-ground chemical defense expression differentially among Asclepias species.

    Science.gov (United States)

    Vannette, Rachel L; Hunter, Mark D; Rasmann, Sergio

    2013-01-01

    Below-ground (BG) symbionts of plants can have substantial influence on plant growth and nutrition. Recent work demonstrates that mycorrhizal fungi can affect plant resistance to herbivory and the performance of above- (AG) and BG herbivores. Although these examples emerge from diverse systems, it is unclear if plant species that express similar defensive traits respond similarly to fungal colonization, but comparative work may inform this question. To examine the effects of arbuscular mycorrhizal fungi (AMF) on the expression of chemical resistance, we inoculated 8 species of Asclepias (milkweed)-which all produce toxic cardenolides-with a community of AMF. We quantified plant biomass, foliar and root cardenolide concentration and composition, and assessed evidence for a growth-defense tradeoff in the presence and absence of AMF. As expected, total foliar and root cardenolide concentration varied among milkweed species. Importantly, the effect of mycorrhizal fungi on total foliar cardenolide concentration also varied among milkweed species, with foliar cardenolides increasing or decreasing, depending on the plant species. We detected a phylogenetic signal to this variation; AMF fungi reduced foliar cardenolide concentrations to a greater extent in the clade including A. curassavica than in the clade including A. syriaca. Moreover, AMF inoculation shifted the composition of cardenolides in AG and BG plant tissues in a species-specific fashion. Mycorrhizal inoculation changed the relative distribution of cardenolides between root and shoot tissue in a species-specific fashion, but did not affect cardenolide diversity or polarity. Finally, a tradeoff between plant growth and defense in non-mycorrhizal plants was mitigated completely by AMF inoculation. Overall, we conclude that the effects of AMF inoculation on the expression of chemical resistance can vary among congeneric plant species, and ameliorate tradeoffs between growth and defense.

  16. Arbuscular mycorrhizal fungi alter above- and below-ground chemical defense expression differentially among Asclepias species

    Directory of Open Access Journals (Sweden)

    Rachel L Vannette

    2013-09-01

    Full Text Available Belowground symbionts of plants can have substantial influence on plant growth and nutrition. Recent work demonstrates that mycorrhizal fungi can affect plant resistance to herbivory and the performance of above and belowground herbivores. Although these examples emerge from diverse systems, it is unclear if plant species that express similar defensive traits respond similarly to fungal colonization, but comparative work may inform this question. To examine the effects of arbuscular mycorrhizal fungi (AMF on the expression of chemical resistance, we inoculated 8 species of Asclepias (milkweed--which all produce toxic cardenolides--with a community of AMF. We quantified plant biomass, foliar and root cardenolide concentration and composition, and assessed evidence for a growth-defense tradeoff in the presence and absence of AMF. As expected, total foliar and root cardenolide concentration varied among milkweed species. Importantly, the effect of mycorrhizal fungi on total foliar cardenolide concentration also varied among milkweed species, with foliar cardenolides increasing or decreasing, depending on the plant species. We detected a phylogenetic signal to this variation; AMF fungi reduced foliar cardenolide concentrations to a greater extent in the clade including A. curassavica than in the clade including A. syriaca. Moreover, AMF inoculation shifted the composition of cardenolides in above- and below-ground plant tissues in a species-specific fashion. Mycorrhizal inoculation changed the relative distribution of cardenolides between root and shoot tissue in a species-specific fashion, but did not affect cardenolide diversity or polarity. Finally, a tradeoff between plant growth and defense in non-mycorrhizal plants was mitigated completely by AMF inoculation. Overall, we conclude that the effects of AMF inoculation on the expression of chemical resistance can vary among congeneric plant species, and ameliorate tradeoffs between growth and

  17. Some inconvenient truths about biosignatures involving two chemical species on Earth-like exoplanets.

    Science.gov (United States)

    Rein, Hanno; Fujii, Yuka; Spiegel, David S

    2014-05-13

    The detection of strong thermochemical disequilibrium in the atmosphere of an extrasolar planet is thought to be a potential biosignature. In this article we present a previously unidentified kind of false positive that can mimic a disequilibrium or any other biosignature that involves two chemical species. We consider a scenario where the exoplanet hosts a moon that has its own atmosphere and neither of the atmospheres is in chemical disequilibrium. Our results show that the integrated spectrum of the planet and the moon closely resembles that of a single object in strong chemical disequilibrium. We derive a firm limit on the maximum spectral resolution that can be obtained for both directly imaged and transiting planets. The spectral resolution of even idealized space-based spectrographs that might be achievable in the next several decades is in general insufficient to break the degeneracy. Both chemical species can only be definitively confirmed in the same object if absorption features of both chemicals can be unambiguously identified and their combined depth exceeds 100%.

  18. The influence of electrohydrodynamic flow on the distribution of chemical species in positive corona

    Science.gov (United States)

    Pontiga, Francisco; Yanallah, Khelifa; Bouazza, R.; Chen, Junhong

    2015-09-01

    A numerical simulation of positive corona discharge in air, including the effect of electrohydrodynamic (EHD) motion of the gas, has been carried out. Air flow is assumed to be confined between two parallel plates, and corona discharge is produced around a thin wire, midway between the plates. Therefore, fluid dynamics equations, including electrical forces, have been solved together with the continuity equation of each neutral species. The plasma chemical model included 24 chemical reactions and ten neutral species, in addition to electrons and positive ions. The results of the simulation have shown that the influence of EHD flow on the spatial distributions of the species is quite different depending on the species. Hence, reactive species like atomic oxygen and atomic nitrogen are confined to the vicinity of the wire, and they are weakly affected by the EHD gas motion. In contrast, nitrogen oxides and ozone are efficiently dragged outside the active region of the corona discharge by the EHD flow. This work was supported by the Spanish Government Agency ``Ministerio de Ciencia e Innovación'' under Contract No. FIS2011-25161.

  19. Soil chemical factors and grassland species density in Emas National Park (central Brazil).

    Science.gov (United States)

    Amorim, P K; Batalha, M A

    2008-05-01

    Studies of grasslands on specific soil types suggest that different nutrients can limit biomass production and, hence, species composition and number. The Brazilian cerrado is the major savanna region in America and once covered about 2 million km(2), mainly in the Brazilian Central Plateau, under seasonal climate, with wet summer and dry winter. In view of the importance of soil chemical factors in the distribution of the vegetation forms within the Cerrado domain and which may influence the number of species, we analyzed some soil characteristics in three herbaceous vegetation forms -- hyperseasonal cerrado, seasonal cerrado, and wet grassland -- in Emas National Park, a core cerrado site, to investigate the relationship between number of species and soil characteristics. We collected vegetation and soil samples in these three vegetation forms and submitted the obtained data to multiple linear regression. We found out that aluminum and pH were the best predictors of species density, the former positively related to species density and the latter negatively related. Since the predictable variation in species density is important in determining areas of conservation, we can postulate that these two soil factors are indicators of high species density areas in tropical grasslands, which could be used in selecting priority sites for conservation.

  20. Stochastic models for turbulent reacting flows

    Energy Technology Data Exchange (ETDEWEB)

    Kerstein, A. [Sandia National Laboratories, Livermore, CA (United States)

    1993-12-01

    The goal of this program is to develop and apply stochastic models of various processes occurring within turbulent reacting flows in order to identify the fundamental mechanisms governing these flows, to support experimental studies of these flows, and to further the development of comprehensive turbulent reacting flow models.

  1. Concentrations and chemical species of arsenic in human urine and hair

    Energy Technology Data Exchange (ETDEWEB)

    Yamato, Naohisa (St. Marianna Univ. School of Medicine, Kawasaki (Japan))

    1988-05-01

    Because marine products are rich in arsenic, the concentration of arsenic in the human urine varies greatly with the state of ingestion of marine products. It has been revealed that inorganic arsenic is methylated in the human body to form MAA (methylarsonic acid) and DMAA (dimethylarsinic acid). It appears therefore that the arsenic present in the human urine is a mixture of the arsenic originating from marine products and the arsenic metabolized in vivo. Recent studies have shown that inorganic arsenic and methylarsenic compounds are quite different in toxicity and effect on the living body due to their difference in chemical species. Finding the chemical species of arsenic in the urine and hair of normal subjects will therefore provide valuable basal data for the biological monitoring of arsenic exposure and for toxicological studies of arsenic.

  2. Important sources and chemical species of ambient fine particles related to adverse health effects

    Science.gov (United States)

    Heo, J.

    2017-12-01

    Although many epidemiological studies have reported that exposure to ambient fine particulate matter (PM2.5) has been linked to increases in mortality and mobidity health outcomes, the key question of which chemical species and sources of PM2.5 are most harmful to public health remains unanswered in the air pollution research area. This study was designed to address the key question with evaluating the risks of exposure to chemical species and source-specific PM2.5 mass on morbidity. Hourly measurements of PM2.5 mass and its major chemical species, including organic carbon, elemental carbon, ions, and trace elements, were observed from January 1 to December 31, 2013 at four of the PM2.5 supersites in urban environments in Korea and the reuslts were used in a positive matrix factorization to estimate source contributions to PM2.5 mass. Nine sources, including secondary sulfate, secondary nitrate, mobile, biomass burning, roadway emission, industry, oil combustion, soil, and aged sea salt, were identified and secondary inorganic aerosol factors (i.e. secondary sulfalte, and secondary nitrate) were the dominant sources contributing to 40% of the total PM2.5 mass in the study region. In order to evaluate the risks of exposure to chemical species and sources of PM2.5 on morbidity, emergency room visits for cardivascular disease and respiratory disease were considered. Hourly health outcomes were compared with hourly measurments of the PM2.5 chemical species and sources using a poission generalized linear model incorporating natural splines, as well as time-stratified case-crossover design. The PM2.5 mass and speveral chemical components, such as organic carbon, elemetal carbon, zinc, and potassium, were strongly associated with morbidity. Source-apporitionmened PM2.5 mass derived from biomass burning, and mobile sources, was significantly associated with cardiovascular and respiratory diseases. The findings represent that local combustion may be particularly important

  3. Tree species traits influence soil physical, chemical, and biological properties in high elevation forests.

    Directory of Open Access Journals (Sweden)

    Edward Ayres

    Full Text Available BACKGROUND: Previous studies have shown that plants often have species-specific effects on soil properties. In high elevation forests in the Southern Rocky Mountains, North America, areas that are dominated by a single tree species are often adjacent to areas dominated by another tree species. Here, we assessed soil properties beneath adjacent stands of trembling aspen, lodgepole pine, and Engelmann spruce, which are dominant tree species in this region and are distributed widely in North America. We hypothesized that soil properties would differ among stands dominated by different tree species and expected that aspen stands would have higher soil temperatures due to their open structure, which, combined with higher quality litter, would result in increased soil respiration rates, nitrogen availability, and microbial biomass, and differences in soil faunal community composition. METHODOLOGY/PRINCIPAL FINDINGS: We assessed soil physical, chemical, and biological properties at four sites where stands of aspen, pine, and spruce occurred in close proximity to one-another in the San Juan Mountains, Colorado. Leaf litter quality differed among the tree species, with the highest nitrogen (N concentration and lowest lignin:N in aspen litter. Nitrogen concentration was similar in pine and spruce litter, but lignin:N was highest in pine litter. Soil temperature and moisture were highest in aspen stands, which, in combination with higher litter quality, probably contributed to faster soil respiration rates from stands of aspen. Soil carbon and N content, ammonium concentration, and microbial biomass did not differ among tree species, but nitrate concentration was highest in aspen soil and lowest in spruce soil. In addition, soil fungal, bacterial, and nematode community composition and rotifer, collembolan, and mesostigmatid mite abundance differed among the tree species, while the total abundance of nematodes, tardigrades, oribatid mites, and prostigmatid

  4. High-performance metabolic profiling of plasma from seven mammalian species for simultaneous environmental chemical surveillance and bioeffect monitoring.

    Science.gov (United States)

    Park, Youngja H; Lee, Kichun; Soltow, Quinlyn A; Strobel, Frederick H; Brigham, Kenneth L; Parker, Richard E; Wilson, Mark E; Sutliff, Roy L; Mansfield, Keith G; Wachtman, Lynn M; Ziegler, Thomas R; Jones, Dean P

    2012-05-16

    High-performance metabolic profiling (HPMP) by Fourier-transform mass spectrometry coupled to liquid chromatography gives relative quantification of thousands of chemicals in biologic samples but has had little development for use in toxicology research. In principle, the approach could be useful to detect complex metabolic response patterns to toxicologic exposures and to detect unusual abundances or patterns of potentially toxic chemicals. As an initial study to develop these possible uses, we applied HPMP and bioinformatics analysis to plasma of humans, rhesus macaques, marmosets, pigs, sheep, rats and mice to determine: (1) whether more chemicals are detected in humans living in a less controlled environment than captive species and (2) whether a subset of plasma chemicals with similar inter-species and intra-species variation could be identified for use in comparative toxicology. Results show that the number of chemicals detected was similar in humans (3221) and other species (range 2537-3373). Metabolite patterns were most similar within species and separated samples according to family and order. A total of 1485 chemicals were common to all species; 37% of these matched chemicals in human metabolomic databases and included chemicals in 137 out of 146 human metabolic pathways. Probability-based modularity clustering separated 644 chemicals, including many endogenous metabolites, with inter-species variation similar to intra-species variation. The remaining chemicals had greater inter-species variation and included environmental chemicals as well as GSH and methionine. Together, the data suggest that HPMP provides a platform that can be useful within human populations and controlled animal studies to simultaneously evaluate environmental exposures and biological responses to such exposures. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  5. Use of chemical elements of 1A family by tropical tree species

    International Nuclear Information System (INIS)

    Carmo, Andrius M.J.; Paiva, Jose Daniel S. de; Magalhaes, Marcelo R.L. de; Franca, Elvis J. de; Hazin, Clovis A.; Bacchi, Marcio A.; Fernandes, Elisabete A.N.

    2013-01-01

    This study aims to evaluate the distribution of K, Rb and Cs in leaves of trees of the Atlantic Forest through studies of correlation between the chemical elements. For this, we used the Instrumental Neutron Activation Analysis for the quantification of the chemical elements. The concentration ranges found were 6700-24000 mg / kg for K, 16 to 72mg / kg for Rb and 0.08 to 0,92mg / kg for Cs. As Rb has chemical similarity to K, is easily absorbed by plants, leading to a high value (0.9) of the Pearson correlation. For the correlation between K and Cs, no significant values were detected except for some species of the Myrtaceae family. However, average correlations (0.6 < r <0.8) between Rb-Cs were obtained for seven plant species of different families. The absence of a specific pattern using of K, Rb and Cs by plants showed great complexity in the distribution of chemical elements in the ecosystem

  6. Steam Gasification of Sawdust Biochar Influenced by Chemical Speciation of Alkali and Alkaline Earth Metallic Species

    Directory of Open Access Journals (Sweden)

    Dongdong Feng

    2018-01-01

    Full Text Available The effect of chemical speciation (H2O/NH4Ac/HCl-soluble and insoluble of alkali and alkaline earth metallic species on the steam gasification of sawdust biochar was investigated in a lab-scale, fixed-bed reactor, with the method of chemical fractionation analysis. The changes in biochar structures and the evolution of biochar reactivity are discussed, with a focus on the contributions of the chemical speciation of alkali and alkaline earth metallic species (AAEMs on the steam gasification of biochar. The results indicate that H2O/NH4Ac/HCl-soluble AAEMs have a significant effect on biochar gasification rates. The release of K occurs mainly in the form of inorganic salts and hydrated ions, while that of Ca occurs mainly as organic ones. The sp3-rich or sp2-sp3 structures and different chemical-speciation AAEMs function together as the preferred active sites during steam gasification. H2O/HCl-soluble AAEMs could promote the transformation of biochar surface functional groups, from ether/alkene C-O-C to carboxylate COO− in biochar, while they may both be improved by NH4Ac-soluble AAEMs. H2O-soluble AAEMs play a crucial catalytic role in biochar reactivity. The effect of NH4Ac-soluble AAEMs is mainly concentrated in the high-conversion stage (biochar conversion >30%, while that of HCl-soluble AAEMs is reflected in the whole activity-testing stage.

  7. Statistical analysis of the velocity and scalar fields in reacting turbulent wall-jets

    Science.gov (United States)

    Pouransari, Z.; Biferale, L.; Johansson, A. V.

    2015-02-01

    The concept of local isotropy in a chemically reacting turbulent wall-jet flow is addressed using direct numerical simulation (DNS) data. Different DNS databases with isothermal and exothermic reactions are examined. The chemical reaction and heat release effects on the turbulent velocity, passive scalar, and reactive species fields are studied using their probability density functions (PDFs) and higher order moments for velocities and scalar fields, as well as their gradients. With the aid of the anisotropy invariant maps for the Reynolds stress tensor, the heat release effects on the anisotropy level at different wall-normal locations are evaluated and found to be most accentuated in the near-wall region. It is observed that the small-scale anisotropies are persistent both in the near-wall region and inside the jet flame. Two exothermic cases with different Damköhler numbers are examined and the comparison revealed that the Damköhler number effects are most dominant in the near-wall region, where the wall cooling effects are influential. In addition, with the aid of PDFs conditioned on the mixture fraction, the significance of the reactive scalar characteristics in the reaction zone is illustrated. We argue that the combined effects of strong intermittency and strong persistency of anisotropy at the small scales in the entire domain can affect mixing and ultimately the combustion characteristics of the reacting flow.

  8. Novel chemical species of Santilli’s magnegas in hadronic chemistry

    International Nuclear Information System (INIS)

    Zodape, Sangesh P.

    2015-01-01

    In this paper we have reviewed the novel chemical species, the magnecules, synthesized by Santilli that comprises of individual atoms, radicals and ordinary molecules bonded through the magnetic attractive forces originating out of toroidal polarization of the orbitals of atomic electrons under strong magnetic fields. The main focus of this paper is to review the fabulous applications of Santill’s magnegas. The novel magnecular species of hydrogen and oxygen find their place in fuel industry especially in fuel cells with the increase in its power, efficiency and total output. In this account we have also considered the flame temperature report of the new magnecular species of gases. We emphasize the importance of this new field

  9. Novel chemical species of Santilli’s magnegas in hadronic chemistry

    Energy Technology Data Exchange (ETDEWEB)

    Zodape, Sangesh P. [Department of Chemistry, Visvesvaraya National Institute of Technology, Nagpur – 440 010, India E-mail: sangesh02@gmail.com (India)

    2015-03-10

    In this paper we have reviewed the novel chemical species, the magnecules, synthesized by Santilli that comprises of individual atoms, radicals and ordinary molecules bonded through the magnetic attractive forces originating out of toroidal polarization of the orbitals of atomic electrons under strong magnetic fields. The main focus of this paper is to review the fabulous applications of Santill’s magnegas. The novel magnecular species of hydrogen and oxygen find their place in fuel industry especially in fuel cells with the increase in its power, efficiency and total output. In this account we have also considered the flame temperature report of the new magnecular species of gases. We emphasize the importance of this new field.

  10. Chemical constituents and biological activities of species of Justicia: a review

    Directory of Open Access Journals (Sweden)

    Geone M. Corrêa

    2012-02-01

    Full Text Available The Acanthaceae family is an important source of therapeutic drugs, and the ethnopharmacological knowledge of this family requires urgent documentation as several of its species are near extinction. Justicia is the largest genus of Acanthaceae, with approximately 600 species. The present work provides a review addressing the chemistry and pharmacology of the genus Justicia. In addition, the biological activities of compounds isolated from the genus are also covered. The chemical and pharmacological information in the present work may inspire new biomedical applications for the species of Justicia, considering atom economy, the synthesis of environmentally benign products without producing toxic by-products, the use of renewable sources of raw materials, and the search for processes with maximal efficiency of energy.

  11. Chemical composition and digestibility of some browse plant species collected from Algerian arid rangelands

    Energy Technology Data Exchange (ETDEWEB)

    Boufennara, S.; Lopez, S.; Boussebouna, H.; Bodas, R.; Bouazza, L.

    2012-11-01

    Many wild browse and bush species are undervalued mainly because of insufficient knowledge about their potential feeding value. The objective was to evaluate some nutritional attributes of various Algerian browse and shub species (Atriplex halimus, Artemisia campestris, Artemisia herba-alba, Astragalus gombiformis, Calobota saharae, Retama raetam, Stipagrostis pungens, Lygeum spartum and Stipa tenacissima). Chemical composition, phenols and tannins concentration, in vitro digestibility, in vitro gas production kinetics and in vitro bio-assay for assessment of tannins using buffered rumen fluid, and in situ disappearence of the edible parts of the plants (leaves, thin twigs and flowers) were determined. In general, protein content in dicotyledon species was always greater than in monocotyledon grasses, these showing higher neutral and acid detergent fibre and lower lignin contents than dicots. The tannin concentrations varied considerably between species, but in general the plants investigated in this study had low tannin contents (except for Artemisia spp. and S. tenacissima). Monocots showed lower in vitro and in situ digestibilities, fermentation rate, cumulative gas production and extent of degradation than dicot species. The plants were clustered by principal components analysis in two groups: poor-quality grasses and the most digestible dicot species. Chemical composition (neutral detergent fibre and protein) and digestibility were the main influential variables determining the ranking. In conclusion, A. halimus, A. campestris, A. herba-alba and A. gombiformis can be considered of greater nutritional value than the highly fibrous and low digestible grasses (S. pungens, L. spartum and S. tenacissima) that should be considered emergency roughages. (Author) 46 refs.

  12. In silico site-directed mutagenesis informs species-specific predictions of chemical susceptibility derived from the Sequence Alignment to Predict Across Species Susceptibility (SeqAPASS) tool

    Science.gov (United States)

    The Sequence Alignment to Predict Across Species Susceptibility (SeqAPASS) tool was developed to address needs for rapid, cost effective methods of species extrapolation of chemical susceptibility. Specifically, the SeqAPASS tool compares the primary sequence (Level 1), functiona...

  13. Comparison of the distribution of some thallium chemical species in mice

    International Nuclear Information System (INIS)

    Petitjean, Francoise.

    Scintigraphic images obtained after injection of radioactive thallium show a strong uptake on the kidneys but also on the intestines, which means that quantitative interpretation of the kidney images is troubled by the superposition of these organs. This study is an attempt to find a chemical form of thallium tending less to fix on the intestinal mucous membrane but keeping its affinity for the medullary zone of the kidney. Various agents forming stable complexes with the metal were investigated. Radiothallium is generally used in the chemical form of monovalent thallium chloride. However the degree of oxidation I is unsuitable for stable complex formation and therefore trivalent thallium was also used. Separation of Tl(I) and Tl(III) with ion exchange resin showed the instability of trivalent chloride at low concentration and when the solution is more than 2 hours old the trivalent thallium solutions injected are 10 -5 M. Calculation of the complex formation constants revealed the absence or formation of monovalent thallium complexes. In all monovalent thallium solutions (with or without carrier, with EDTA or HEDTA) the predominant chemical species is Tl + . In the case of trivalent thallium three solutions with carrier were used; the predominant species is TlCl 6 3- when the solution contains Cl - and EDTA and TlEDTA when Cl - , NO 3 - and EDTA are present. These solutions were injected intraveinously into mice in order to study the radiothallium distribution in the kidney and intestine by comparison with that of TlCl while the chemical species varied from one preparation to another no great difference in the radiothallium distribution was observed [fr

  14. 29Si NMR Chemical Shift Calculation for Silicate Species by Gaussian Software

    Science.gov (United States)

    Azizi, S. N.; Rostami, A. A.; Godarzian, A.

    2005-05-01

    Hartree-Fock self-consistent-field (HF-SCF) theory and the Gauge-including atomic orbital (GIAO) methods are used in the calculation of 29Si NMR chemical shifts for ABOUT 90 units of 19 compounds of various silicate species of precursors for zeolites. Calculations have been performed at geometries optimized at the AM1 semi-empirical method. The GIAO-HF-SCF calculations were carried out with using three different basis sets: 6-31G*, 6-31+G** and 6-311+G(2d,p). To demonstrate the quality of the calculations the calculated chemical shifts, δ, were compared with the corresponding experimental values for the compounds in study. The results, especially with 6-31+g** are in excellent agreement with experimental values. The calculated chemical shifts, in practical point of view, appear to be accurate enough to aid in experimental peak assignments. The difference between the experimental and calculated 29Si chemical shift values not only depends on the Qn units but also it seems that basis set effects and the level of theory is more important. For the series of molecules studied here, the standard deviations and mean absolute errors for 29Si chemical shifts relative to TMS determined using Hartree--Fock 6-31+G** basis is nearly in all cases smaller than the errors for shifts determined using HF/6-311+G(2d,p).

  15. Computational Investigation of Soot and Radiation in Turbulent Reacting Flows

    Science.gov (United States)

    Lalit, Harshad

    scalars from the LES are used in conjunction with the radiation heat transfer equation and a narrow band radiation model to compute time dependent and time averaged images of infrared radiation intensity in spectral bands corresponding to molecular radiation from gas phase carbon dioxide and soot particles exclusively. While qualitative and quantitative comparisons with measured images in the CO2 radiation band show that the flame structure is correctly computed, images computed in the soot radiation band illustrate that the soot volume fraction is under predicted by the computations. The effect of the soot model and cause of under prediction is investigated further by correcting the soot volume fraction using an empirical state relationship. By comparing default simulations with computations using the state relation, it is shown that while the soot model under-estimates the soot concentration, it correctly computes the intermittency of soot in the flame. The study of sooting flames is extended further by performing a parametric analysis of physical and numerical parameters that affect soot formation and transport in two laboratory scale turbulent sooting flames, one fueled by natural gas and the other by ethylene. The study is focused on investigating the effect of molecular diffusion of species, dilution of fuel with hydrogen gas and the effect of chemical reaction mechanism on the soot concentration in the flame. The effect of species Lewis numbers on soot evolution and transport is investigated by carrying out simulations, first with the default equal diffusivity (ED) assumption and then by incorporating a differential diffusion (DD) model. Computations using the DD model over-estimate the concentration of the soot precursor and soot oxidizer species, leading to inconsistencies in the estimate of the soot concentration. The linear differential diffusion (LDD) model, reported previously to consistently model differential diffusion effects is implemented to correct the

  16. Differential Sharing of Chemical Cues by Social Parasites Versus Social Mutualists in a Three-Species Symbiosis.

    Science.gov (United States)

    Emery, Virginia J; Tsutsui, Neil D

    2016-04-01

    Chemical recognition systems are crucial for maintaining the unity of social insect colonies. It has been proposed that colonies form a common chemical signature, called the gestalt odor, which is used to distinguish colony members and non-members. This chemical integration is achieved actively through social interactions such as trophallaxis and allogrooming, or passively such as through exposure to common nest material. When colonies are infiltrated by social parasites, the intruders often use some form of chemical mimicry. However, it is not always clear how this chemical mimicry is accomplished. Here, we used a three-species nesting symbiosis to test the differences in chemical integration of mutualistic (parabiotic) and parasitic ant species. We found that the parasite (Solenopsis picea) obtains chemical cues from both of the two parabiotic host ant species. However, the two parabiotic species (Crematogaster levior and Camponotus femoratus) maintain species-specific cues, and do not acquire compounds from the other species. Our findings suggest that there is a fundamental difference in how social mutualists and social parasites use chemicals to integrate themselves into colonies.

  17. A Review of Botany and Pharmacological Effect and Chemical Composition of Echinophora Species Growing in Iran.

    Science.gov (United States)

    Hosseini, Zohreh; Lorigooini, Zahra; Rafieian-Kopaei, Mahmoud; Shirmardi, Hamzeh Ali; Solati, Kamal

    2017-01-01

    This review was conducted to investigate the botany, phytochemistry, and pharmacological properties of Echinophora species. The information of this review was obtained by searching for keywords Apiaceae , Echinophora , pharmacological effects, and traditional and modern medicine in scientific articles and books published in search engines Scopus, Google Scholar, Science Direct, PubMed, and Web of Science. The traditional uses of Echinophora and the existence of valuable phytochemicals in the plant have led to isolation and drug discovery of natural medicines such as antibiotic, analgesics, and anticancer drugs, and the beneficial effects of these plants can widely be used in healthcare. Echinophora species are medicinal and aromatic plants that are belong to Apiaceae family. This genus have four species in Iran. The botany, geographical distribution, traditional and pharmacological effects of Echinophora genus were described. Also, the major chemical constituents of the essential oil and extract of different species of Echinophora that have been reported. Overall, the existence of valuable phytochemicals purpose Echinophora species as novel candidate to isolation and drug discovery of natural medicines such as antibiotic, analgesics, and anticancer drugs.

  18. Antimicrobial Activity and Chemical Composition of Essential Oils from Verbenaceae Species Growing in South America

    Directory of Open Access Journals (Sweden)

    Cristina M. Pérez Zamora

    2018-03-01

    Full Text Available The Verbenaceae family includes 2600 species grouped into 100 genera with a pantropical distribution. Many of them are important elements of the floras of warm-temperature and tropical regions of America. This family is known in folk medicine, and its species are used as digestive, carminative, antipyretic, antitussive, antiseptic, and healing agents. This review aims to collect information about the essential oils from the most reported species of the Verbenaceae family growing in South America, focusing on their chemical composition, antimicrobial activity, and synergism with commercial antimicrobials. The information gathered comprises the last twenty years of research within the South American region and is summarized taking into consideration the most representative species in terms of their essential oils. These species belong to Aloysia, Lantana, Lippia, Phyla, and Stachytarpheta genera, and the main essential oils they contain are monoterpenes and sesquiterpenes, such as β-caryophyllene, thymol, citral, 1,8-cineole, carvone, and limonene. These compounds have been found to possess antimicrobial activities. The synergism of these essential oils with antibiotics is being studied by several research groups. It constitutes a resource of interest for the potential use of combinations of essential oils and antibiotics in infection treatments.

  19. Phytotoxic activity and chemical composition of aqueous volatile fractions from Eucalyptus species.

    Directory of Open Access Journals (Sweden)

    Jinbiao Zhang

    Full Text Available The essential oils from four Eucalyptus species (E. spathulata, E. salubris, E. brockwayii and E. dundasii have been previously confirmed to have stronger inhibitory effects on germination and seedling growth of silverleaf nightshade (Solanum elaeagnifolium Cav.. The aqueous volatile fractions (AVFs were the water soluble volatile fractions produced together with the essential oils (water insoluble fractions during the steam distillation process. The aim of this study was to further assess the phytotoxicity of AVFs from the four Eucalyptus species and their chemical composition. The fresh leaves of the four Eucalyptus species were used for the extraction of AVFs. The AVFs were tested for their phytotoxic effects on the perennial weed, silverleaf nightshade under laboratory conditions. The chemical compositions of the AVFs were determined by gas chromatograph-mass spectrometry (GC-MS. Our results showed that the AVFs had strong inhibition on the germination and seedling growth of silverleaf nightshade. The inhibition index increased with the increasing concentrations of AVFs. The inhibitory effects of the AVFs varied between different Eucalyptus species. The AVF from E. salubris demonstrated the highest inhibitory activity on the weed tested, with complete inhibition on germination and seedling growth at a concentration of 75%. The GC-MS analysis revealed that 1,8-cineole, isopentyl isovalerate, isomenthol, pinocarvone, trans-pinocarveol, alpha-terpineol and globulol were the main compounds in the AVFs. These results indicated that all AVFs tested had differential inhibition on the germination and seedling growth of silverleaf nightshade, which could be due to the joint effects of compounds present in the AVFs as these compounds were present in different quantities and ratio between Eucalyptus species.

  20. Phytotoxic Activity and Chemical Composition of Aqueous Volatile Fractions from Eucalyptus Species

    Science.gov (United States)

    Zhang, Jinbiao; An, Min; Wu, Hanwen; Liu, De Li; Stanton, Rex

    2014-01-01

    The essential oils from four Eucalyptus species (E. spathulata, E. salubris, E. brockwayii and E. dundasii) have been previously confirmed to have stronger inhibitory effects on germination and seedling growth of silverleaf nightshade (Solanum elaeagnifolium Cav.). The aqueous volatile fractions (AVFs) were the water soluble volatile fractions produced together with the essential oils (water insoluble fractions) during the steam distillation process. The aim of this study was to further assess the phytotoxicity of AVFs from the four Eucalyptus species and their chemical composition. The fresh leaves of the four Eucalyptus species were used for the extraction of AVFs. The AVFs were tested for their phytotoxic effects on the perennial weed, silverleaf nightshade under laboratory conditions. The chemical compositions of the AVFs were determined by gas chromatograph–mass spectrometry (GC-MS). Our results showed that the AVFs had strong inhibition on the germination and seedling growth of silverleaf nightshade. The inhibition index increased with the increasing concentrations of AVFs. The inhibitory effects of the AVFs varied between different Eucalyptus species. The AVF from E. salubris demonstrated the highest inhibitory activity on the weed tested, with complete inhibition on germination and seedling growth at a concentration of 75%. The GC-MS analysis revealed that 1,8-cineole, isopentyl isovalerate, isomenthol, pinocarvone, trans-pinocarveol, alpha-terpineol and globulol were the main compounds in the AVFs. These results indicated that all AVFs tested had differential inhibition on the germination and seedling growth of silverleaf nightshade, which could be due to the joint effects of compounds present in the AVFs as these compounds were present in different quantities and ratio between Eucalyptus species. PMID:24681490

  1. Modeling non-isothermal multiphase multi-species reactive chemical transport in geologic media

    Energy Technology Data Exchange (ETDEWEB)

    Tianfu Xu; Gerard, F.; Pruess, K.; Brimhall, G.

    1997-07-01

    The assessment of mineral deposits, the analysis of hydrothermal convection systems, the performance of radioactive, urban and industrial waste disposal, the study of groundwater pollution, and the understanding of natural groundwater quality patterns all require modeling tools that can consider both the transport of dissolved species as well as their interactions with solid (or other) phases in geologic media and engineered barriers. Here, a general multi-species reactive transport formulation has been developed, which is applicable to homogeneous and/or heterogeneous reactions that can proceed either subject to local equilibrium conditions or kinetic rates under non-isothermal multiphase flow conditions. Two numerical solution methods, the direct substitution approach (DSA) and sequential iteration approach (SIA) for solving the coupled complex subsurface thermo-physical-chemical processes, are described. An efficient sequential iteration approach, which solves transport of solutes and chemical reactions sequentially and iteratively, is proposed for the current reactive chemical transport computer code development. The coupled flow (water, vapor, air and heat) and solute transport equations are also solved sequentially. The existing multiphase flow code TOUGH2 and geochemical code EQ3/6 are used to implement this SIA. The flow chart of the coupled code TOUGH2-EQ3/6, required modifications of the existing codes and additional subroutines needed are presented.

  2. Relations between chemical species distribution and the fluctuating activity of Vulcano (Italy)

    Energy Technology Data Exchange (ETDEWEB)

    Martini, M.; Legittimo, P.C.

    1984-09-01

    Five years of systematic observation of the fumaroles of Vulcano have permitted the detection of some compositional trends coincident with a fluctuation in temperature. A gradual decrease of CO/sub 2/, H/sub 2/S+SO/sup 2/, HF was observed with the lowering of temperature, while HCl slightly increased. These physical-chemical characteristics of the system are not readily explained as simply produced by different stages in magma degassing, and the previous hypothesis of the insignificant influence of a brackish aquifer on the fumaroles still appears a reliable working model. R-mode factor analysis allowed the differentiated role of chemical species to be distinguished for which different genetic processes can be derived. The ratios HF/HCl and SO/sub 2//H/sub 2/S are taken as indicators of the changing activity of the system, and also the available data for Usu (Japan) and Mount St. Helens (USA) are considered.

  3. Light-Addressable Potentiometric Sensors for Quantitative Spatial Imaging of Chemical Species.

    Science.gov (United States)

    Yoshinobu, Tatsuo; Miyamoto, Ko-Ichiro; Werner, Carl Frederik; Poghossian, Arshak; Wagner, Torsten; Schöning, Michael J

    2017-06-12

    A light-addressable potentiometric sensor (LAPS) is a semiconductor-based chemical sensor, in which a measurement site on the sensing surface is defined by illumination. This light addressability can be applied to visualize the spatial distribution of pH or the concentration of a specific chemical species, with potential applications in the fields of chemistry, materials science, biology, and medicine. In this review, the features of this chemical imaging sensor technology are compared with those of other technologies. Instrumentation, principles of operation, and various measurement modes of chemical imaging sensor systems are described. The review discusses and summarizes state-of-the-art technologies, especially with regard to the spatial resolution and measurement speed; for example, a high spatial resolution in a submicron range and a readout speed in the range of several tens of thousands of pixels per second have been achieved with the LAPS. The possibility of combining this technology with microfluidic devices and other potential future developments are discussed.

  4. Plant Species Rather Than Climate Greatly Alters the Temporal Pattern of Litter Chemical Composition During Long-Term Decomposition

    Science.gov (United States)

    Li, Yongfu; Chen, Na; Harmon, Mark E.; Li, Yuan; Cao, Xiaoyan; Chappell, Mark A.; Mao, Jingdong

    2015-10-01

    A feedback between decomposition and litter chemical composition occurs with decomposition altering composition that in turn influences the decomposition rate. Elucidating the temporal pattern of chemical composition is vital to understand this feedback, but the effects of plant species and climate on chemical changes remain poorly understood, especially over multiple years. In a 10-year decomposition experiment with litter of four species (Acer saccharum, Drypetes glauca, Pinus resinosa, and Thuja plicata) from four sites that range from the arctic to tropics, we determined the abundance of 11 litter chemical constituents that were grouped into waxes, carbohydrates, lignin/tannins, and proteins/peptides using advanced 13C solid-state NMR techniques. Decomposition generally led to an enrichment of waxes and a depletion of carbohydrates, whereas the changes of other chemical constituents were inconsistent. Inconsistent convergence in chemical compositions during decomposition was observed among different litter species across a range of site conditions, whereas one litter species converged under different climate conditions. Our data clearly demonstrate that plant species rather than climate greatly alters the temporal pattern of litter chemical composition, suggesting the decomposition-chemistry feedback varies among different plant species.

  5. Vaporization of chemical species and the production of aerosols during a core debris/concrete interaction

    International Nuclear Information System (INIS)

    Butland, A.T.D.; Mignanelli, M.A.; Potter, P.E.; Smith, P.N.

    1987-01-01

    The equilibrium chemical composition within gas bubbles sparging through isothermal molten corium-concrete mixtures has been evaluated theoretically. A series of sensitivity calculations gives some insight into a number of factors which are of importance in determining the radionuclide and non-radioactive releases during core-concrete interaction. The degree of mixing or layering of the pool has turned out to be of paramount importance in determining the magnitudes of the releases. The presence of unoxidized zirconium in the melt tends to enhance the release of a number of species and the type of concrete used for the base mat can have a significant effect. The predictions can be sensitive to the thermodynamic data used in the calculations. The vaporization of various species into the gas bubbles can require large amounts of heat; the loss of this heat from the melt can have an effect on the extent of the vaporization

  6. Penicillium arizonense, a new, genome sequenced fungal species, reveals a high chemical diversity in secreted metabolites

    DEFF Research Database (Denmark)

    Grijseels, Sietske; Nielsen, Jens Christian; Randelovic, Milica

    2016-01-01

    A new soil-borne species belonging to the Penicillium section Canescentia is described, Penicillium arizonense sp. nov. (type strain CBS 141311T = IBT 12289T). The genome was sequenced and assembled into 33.7 Mb containing 12,502 predicted genes. A phylogenetic assessment based on marker genes...... confirmed the grouping of P. arizonense within section Canescentia. Compared to related species, P. arizonense proved to encode a high number of proteins involved in carbohydrate metabolism, in particular hemicellulases. Mining the genome for genes involved in secondary metabolite biosynthesis resulted...... of biosynthetic gene clusters in P. arizonense responsible for the synthesis of all detected compounds except curvulinic acid. The capacity to produce biomass degrading enzymes and the identification of a high chemical diversity in secreted bioactive secondary metabolites, offers a broad range of potential...

  7. Model analysis of the chemical conversion of exhaust species in the expanding plumes of subsonic aircraft

    Energy Technology Data Exchange (ETDEWEB)

    Moellhoff, M.; Hendricks, J.; Lippert, E.; Petry, H. [Koeln Univ. (Germany). Inst. fuer Geophysik und Meteorologie; Sausen, R. [Deutsche Forschungsanstalt fuer Luft- und Raumfahrt e.V. (DLR), Oberpfaffenhofen (Germany). Inst. fuer Physik der Atmosphaere

    1997-12-31

    A box model and two different one-dimensional models are used to investigate the chemical conversion of exhaust species in the dispersing plume of a subsonic aircraft flying at cruise altitude. The effect of varying daytime of release as well as the impact of changing dispersion time is studied with special respect to the aircraft induced O{sub 3} production. Effective emission amounts for consideration in mesoscale and global models are calculated. Simulations with modified photolysis rates are performed to show the sensitivity of the photochemistry to the occurrence of cirrus clouds. (author) 8 refs.

  8. Model analysis of the chemical conversion of exhaust species in the expanding plumes of subsonic aircraft

    Energy Technology Data Exchange (ETDEWEB)

    Moellhoff, M; Hendricks, J; Lippert, E; Petry, H [Koeln Univ. (Germany). Inst. fuer Geophysik und Meteorologie; Sausen, R [Deutsche Forschungsanstalt fuer Luft- und Raumfahrt e.V. (DLR), Oberpfaffenhofen (Germany). Inst. fuer Physik der Atmosphaere

    1998-12-31

    A box model and two different one-dimensional models are used to investigate the chemical conversion of exhaust species in the dispersing plume of a subsonic aircraft flying at cruise altitude. The effect of varying daytime of release as well as the impact of changing dispersion time is studied with special respect to the aircraft induced O{sub 3} production. Effective emission amounts for consideration in mesoscale and global models are calculated. Simulations with modified photolysis rates are performed to show the sensitivity of the photochemistry to the occurrence of cirrus clouds. (author) 8 refs.

  9. Status of chemical elements in Atlantic Forest tree species near an industrial complex

    International Nuclear Information System (INIS)

    Araujo, A.L.L.; Fernandes, E.A.N.; Franca, E.J.; Bacchi, M.A.

    2008-01-01

    Environmental quality assessment studies have been conducted with tree species largely distributed in the Atlantic Forest. Leaf and soil samples were collected in the conservation unit Parque Estadual da Serra do Mar (PESM) nearby the industrial complex of Cubatao, Sao Paulo State, Brazil, and analyzed for chemical elements by instrumental neutron activation analysis. Results were compared to background values obtained in the Parque Estadual Carlos Botelho (PECB). The higher As, Fe, Hg and Zn mass fractions in the tree leaves of PESM indicated anthropogenic influence on this conservation unit. (author)

  10. The biological activities and chemical composition of Pereskia species (Cactaceae)--a review.

    Science.gov (United States)

    Pinto, Nícolas de Castro Campos; Scio, Elita

    2014-09-01

    The exploration of nature as a source of sustainable, novel bioactive substances continues to grow as natural products play a significant role in the search for new therapeutic and agricultural agents. In this context, plants of the genus Pereskia (Cactaceae) have been studied for their biological activities, and are evolving as an interesting subject in the search for new, bioactive compounds. These species are commonly used as human foodstuffs and in traditional medicine to treat a variety of diseases. This review focuses on the bioactivity and chemical composition of the genus Pereskia, and aims to stimulate further studies on the chemistry and biological potential of the genus.

  11. Comparison of the chemical compositions and nutritive values of various pumpkin (Cucurbitaceae) species and parts

    Science.gov (United States)

    Kim, Mi Young; Kim, Eun Jin; Kim, Young-Nam; Choi, Changsun

    2012-01-01

    Pumpkins have considerable variation in nutrient contents depending on the cultivation environment, species, or part. In this study, the general chemical compositions and some bioactive components, such as tocopherols, carotenoids, and β-sitosterol, were analyzed in three major species of pumpkin (Cucurbitaceae pepo, C. moschata, and C. maxima) grown in Korea and also in three parts (peel, flesh, and seed) of each pumpkin species. C. maxima had significantly more carbohydrate, protein, fat, and fiber than C. pepo or C. moschata (P pumpkin was highest in C. pepo. The major fatty acids in the seeds were palmitic, stearic, oleic, and linoleic acids. C. pepo and C. moschata seeds had significantly more γ-tocopherol than C. maxima, whose seeds had the highest β-carotene content. C. pepo seeds had significantly more β-sitosterol than the others. Nutrient compositions differed considerably among the pumpkin species and parts. These results will be useful in updating the nutrient compositions of pumpkin in the Korean food composition database. Additional analyses of various pumpkins grown in different years and in different areas of Korea are needed. PMID:22413037

  12. Penicillium arizonense, a new, genome sequenced fungal species, reveals a high chemical diversity in secreted metabolites

    Science.gov (United States)

    Grijseels, Sietske; Nielsen, Jens Christian; Randelovic, Milica; Nielsen, Jens; Nielsen, Kristian Fog; Workman, Mhairi; Frisvad, Jens Christian

    2016-01-01

    A new soil-borne species belonging to the Penicillium section Canescentia is described, Penicillium arizonense sp. nov. (type strain CBS 141311T = IBT 12289T). The genome was sequenced and assembled into 33.7 Mb containing 12,502 predicted genes. A phylogenetic assessment based on marker genes confirmed the grouping of P. arizonense within section Canescentia. Compared to related species, P. arizonense proved to encode a high number of proteins involved in carbohydrate metabolism, in particular hemicellulases. Mining the genome for genes involved in secondary metabolite biosynthesis resulted in the identification of 62 putative biosynthetic gene clusters. Extracts of P. arizonense were analysed for secondary metabolites and austalides, pyripyropenes, tryptoquivalines, fumagillin, pseurotin A, curvulinic acid and xanthoepocin were detected. A comparative analysis against known pathways enabled the proposal of biosynthetic gene clusters in P. arizonense responsible for the synthesis of all detected compounds except curvulinic acid. The capacity to produce biomass degrading enzymes and the identification of a high chemical diversity in secreted bioactive secondary metabolites, offers a broad range of potential industrial applications for the new species P. arizonense. The description and availability of the genome sequence of P. arizonense, further provides the basis for biotechnological exploitation of this species. PMID:27739446

  13. A novel technology for neutralizing acidity and attenuating toxic chemical species from acid mine drainage using cryptocrystalline magnesite tailings

    CSIR Research Space (South Africa)

    Masindi, Vhahangwele

    2016-04-01

    Full Text Available neutralize and attenuate elevated concentrations of chemical species in AMD to within prescribed legal frameworks for water use in agricultural and industrial sectors in South Africa....

  14. Chemical composition and fuel wood characteristics of fast growing tree species in India

    Science.gov (United States)

    Chauhan, S. K.; Soni, R.

    2012-04-01

    India is one of the growing economy in the world and energy is a critical input to sustain the growth of development. Country aims at security and efficiency of energy. Though fossil fuel will continue to play a dominant role in energy scenario but country is committed to global environmental well being thus stressing on environment friendly technologies. Concerns of energy security in this changing climatic situation have led to increasing support for the development of new renewable source of energy. Government though is determined to facilitate bio-energy and many projects have been established but initial after-affects more specifically on the domestic fuelwood are evident. Even the biomass power generating units are facing biomass crisis and accordingly the prices are going up. The CDM projects are supporting the viability of these units resultantly the Indian basket has a large number of biomass projects (144 out of total 506 with 28 per cent CERs). The use for fuelwood as a primary source of energy for domestic purpose by the poor people (approx. 80 per cent) and establishment of bio-energy plants may lead to deforestation to a great extent and only solution to this dilemma is to shift the wood harvest from the natural forests to energy plantations. However, there is conspicuous lack of knowledge with regards to the fuelwood characteristics of fast growing tree species for their selection for energy plantations. The calorific value of the species is important criteria for selection for fuel but it is affected by the proportions of biochemical constituents present in them. The aim of the present work was to study the biomass production, calorific value and chemical composition of different short rotation tree species. The study was done from the perspective of using the fast growing tree species for energy production at short rotation and the study concluded that short rotation tree species like Gmelina arborea, Eucalyptus tereticornis, Pongamia pinnata

  15. In vitro activity of natural and chemical products on sporulation of Eimeria species oocysts of chickens.

    Science.gov (United States)

    Gadelhaq, Sahar M; Arafa, Waleed M; Abolhadid, Shawky M

    2018-02-15

    This study was designed to investigate the ability of two herbal extracts and different chemical substances to inhibit or disrupt sporulation of Eimeria species oocysts of the chickens. The two herbal extracts were Allium sativum (garlic) and Moringa olifiera while the chemical substances included commercial disinfectants and diclazuril. Field isolates of Eimeria oocysts were propagated in chickens to obtain a continuous source of oocysts. The collected unsporulated oocysts (10 5 oocysts/5 ml) were dispensed into 5 cm Petri dish. Three replicates were used for each treatment. The treated oocysts were incubated for 48 h at 25-29 °C and 80% relative humidity. The results showed that herbal extracts, the commercial recommended dose of Dettol, TH4, Phenol, Virkon ® S, and Diclazuril 20% have no effect on the sporulation. While Sodium hypochlorite showed a significant degree of sporulation inhibition reached to 49.67%. Moreover, 70% ethanol, and 10% formalin showed 100% sporulation inhibition. It was concluded that 70% ethanol and 10% formalin are the most effective methods to inhibit Eimeria species sporulation. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. Bufadienolides of Kalanchoe species: an overview of chemical structure, biological activity and prospects for pharmacological use.

    Science.gov (United States)

    Kolodziejczyk-Czepas, Joanna; Stochmal, Anna

    2017-01-01

    Toad venom is regarded as the main source of bufadienolides; however, synthesis of these substances takes also place in a variety of other animal and plant organisms, including ethnomedicinal plants of the Kalanchoe genus. Chemically, bufadienolides are a group of polyhydroxy C-24 steroids and their glycosides, containing a six-membered lactone (α-pyrone) ring at the C-17β position. From the pharmacological point of view, bufadienolides might be a promising group of steroid hormones with cardioactive properties and anticancer activity. Most of the literature concerns bufadienolides of animal origin; however, the medicinal use of these compounds remains limited by their narrow therapeutic index and the risk of development of cardiotoxic effects. On the other hand, plants such as Kalanchoe are also a source of bufadienolides. Kalanchoe pinnata (life plant, air plant, cathedral bells), Kalanchoe daigremontiana (mother of thousands) and other Kalanchoe species are valuable herbs in traditional medicine of Asia and Africa. The present review focuses on the available data on chemical structures of 31 compounds, biological properties and prospects for therapeutic use of bufadienolides from Kalanchoe species. Furthermore, it presents some new investigational trends in research on curative uses of these substances.

  17. Vibrational Spectroscopy of Chemical Species in Silicon and Silicon-Rich Nitride Thin Films

    Directory of Open Access Journals (Sweden)

    Kirill O. Bugaev

    2012-01-01

    Full Text Available Vibrational properties of hydrogenated silicon-rich nitride (SiN:H of various stoichiometry (0.6≤≤1.3 and hydrogenated amorphous silicon (a-Si:H films were studied using Raman spectroscopy and Fourier transform infrared spectroscopy. Furnace annealing during 5 hours in Ar ambient at 1130∘C and pulse laser annealing were applied to modify the structure of films. Surprisingly, after annealing with such high-thermal budget, according to the FTIR data, the nearly stoichiometric silicon nitride film contains hydrogen in the form of Si–H bonds. From analysis of the FTIR data of the Si–N bond vibrations, one can conclude that silicon nitride is partly crystallized. According to the Raman data a-Si:H films with hydrogen concentration 15% and lower contain mainly Si–H chemical species, and films with hydrogen concentration 30–35% contain mainly Si–H2 chemical species. Nanosecond pulse laser treatments lead to crystallization of the films and its dehydrogenization.

  18. The spatial and temporal distribution of chemical species in Padaviya Reservoir, Sri Lanka.

    Science.gov (United States)

    Koliyabandara, S. M. P. A.; Siriwardhana, C.; Cooray, P. L. A. T.; Liyanage, S. S.

    2017-12-01

    Water is one of the most important assets for human life. Eutrophication and pollution are some of the major threats to many freshwater bodies. There are thousands of reservoirs exist in Sri Lanka; however, only a handful of them has been thoroughly monitored and studied. The main objective of this study is to investigate the temporal and spatial distribution of chemical species in Padaviya reservoir which is shallow man-made irrigation reservoir (8°49'30.6" N and 80°46'2.05"E) located in Sri Lanka constructed around 300 BC. The average depth is 8 m and 4 m in wet and dry seasons respectively. It has a catchment area of 270 km2. Water sampling was done at bi-monthly intervals for a period of one year staring from January 2016. Chemical analyses were conducted according to standard protocols. The maximum temperature difference between the surface and bottom waters of the reservoir was 2 °C throughout the year. The surface and bottom water conductivity varied between 175 ± 2.3 to 250 ± 3.0 μS cm-1 and 475 ± 3.7 to 600 ± 4.5 μScm-1 respectively. The average pH of surface and bottom waters varied between 8.5 ± 0.1 to 7.8 ± 0.2 and 7.2 ± 0.02 to 6.8 ± 0.2 respectively. The dissolved oxygen concentration showed a clinograde type distribution throughout the year where the surface waters were well oxygenated (DO ≈ 7.5 ppm) and the bottom waters were anoxic (DO ≈ 0.15 ppm). Ammonia concentration increased with the depth from surface concentration of 150 ± 50 to 300 ± 25 ppb at the bottom. Nitrite distribution was similar to ammonia and the surface concentration was 100 ± 25ppb throughtout the year and at the bottom it varied between 300 ± 30 to 4500 ± 30 ppb. Water soluble phosphate distribution was also similar to ammonia. The surface concentration was 200 ± 20 ppb throughtout the year and varied from 100 ± 20 to 2000 ±20 ppb at the bottom. Nitrate distribution was inverse of the ammonia. The surface concentration was 500 ± 30 to 900 ± 30 ppb

  19. Chemical composition and antibacterial activities of seven Eucalyptus species essential oils leaves.

    Science.gov (United States)

    Sebei, Khaled; Sakouhi, Fawzi; Herchi, Wahid; Khouja, Mohamed Larbi; Boukhchina, Sadok

    2015-01-19

    In this paper, we have studied the essential oils chemical composition of the leaves of seven Eucalyptus species developed in Tunisia. Eucalyptus leaves were picked from trees growing in different arboretums in Tunisia. Choucha and Mrifeg arboretums located in Sedjnene, region of Bizerte (Choucha: E. maideni, E. astrengens et E. cinerea; Mrifeg : E. leucoxylon), Korbous arboretums located in the region of Nabeul, North East Tunisia with sub-humid bioclimate, (E. lehmani), Souiniet-Ain Drahem arboretum located in region of Jendouba (E. sideroxylon, E. bicostata). Essential oils were individually tested against a large panel of microorganisms including Staphylococcus aureus (ATCC 6539), Escherichia coli (ATCC 25922), Enterococcus faecalis (ATCC29212), Listeria ivanovii (RBL 30), Bacillus cereus (ATCC11778). The yield of essential oils ranged from 1.2% to 3% (w/w) for the different Eucalyptus species. All essential oils contain α-pinene, 1,8-cineol and pinocarveol-trans for all Eucalyptus species studied. The 1,8-cineol was the major compound in all species (49.07 to 83.59%). Diameter of inhibition zone of essential oils of Eucalyptus species varied from 10 to 29 mm. The largest zone of inhibition was obtained for Bacillus cereus (E. astrengens) and the lowest for Staphylococcus aureus (E. cinerea). The essential oils from E. maideni, E. astrengens, E. cinerea (arboretum of Bizerte), E. bicostata (arboretum of Aindraham) showed the highest antibacterial activity against Listeria ivanovii and Bacillus cereus. The major constituents of Eucalyptus leaves essential oils are 1,8-cineol (49.07 to 83.59%) and α-pinene (1.27 to 26.35%). The essential oils from E. maideni, E. astrengens, E. cinerea, E. bicostata showed the highest antibacterial activity against Listeria ivanovii and Bacillus cereus, they may have potential applications in food and pharmaceutical products.

  20. The effect of elevated CO2 on the chemical composition and construction costs of leaves of 27 C-3 species

    NARCIS (Netherlands)

    Poorter, H; VanBerkel, Y; Baxter, R; DenHertog, J; Dijkstra, P; Gifford, RM; Griffin, KL; Roumet, C; Roy, J

    We determined the proximate chemical composition as well as the construction costs of leaves of 27 species, grown at ambient and at a twice-ambient partial pressure of atmospheric CO2, These species comprised wild and agricultural herbaceous plants as well as tree seedlings, Both average responses

  1. The effect of elevated CO2 on the chemical composition and construction costs of leaves of 27 C3 species

    NARCIS (Netherlands)

    Poorter, H.; Berkel, Y. van; Baxter, B.; Hertog, J. den; Dijkstra, P.; Gifford, R.M.; Griffin, K.L.; Roumet, C.; Roy, J.; Wong, S.C.

    1997-01-01

    We determined the proximate chemical composition as well as the construction costs of leaves of 27 species, grown at ambient and at a twice-ambient partial pressure of atmospheric CO₂. These species comprised wild and agricultural herbaceous plants as well as tree seedlings. Both average

  2. Reacting plasma project at IPP Japan

    International Nuclear Information System (INIS)

    Miyahara, A.; Momota, H.; Hamada, Y.; Kawamura, K.; Akimune, H.

    1981-01-01

    Contributed papers of the seminar on burning plasma held at UCLA are collected. Paper on ''overview of reacting plasma project'' described aim and philosophy of R-Project in Japan. Paper on ''Burning plasma and requirements for design'' gave theoretical aspect of reacting plasma physics while paper on ''plasma container, heating and diagnostics'' treated experimental aspect. Tritium handling is essential for the next step experiment; therefore, paper on ''Tritium problems in burning plasma experiments'' took an important part of this seminar. As appendix, paper on ''a new type of D - ion source using Si-semiconductor'' was added because such an advanced R and D work is essential for R-Project. (author)

  3. Preparation of Ti species coating hydrotalcite by chemical vapor deposition for photodegradation of azo dye.

    Science.gov (United States)

    Xiao, Gaofei; Zeng, HongYan; Xu, Sheng; Chen, ChaoRong; Zhao, Quan; Liu, XiaoJun

    2017-10-01

    TiO 2 in anatase crystal phase is a very effective catalyst in the photocatalytic oxidation of organic compounds in water. To improve its photocatalytic activity, the Ti-coating MgAl hydrotalcite (Ti-MgAl-LDH) was prepared by chemical vapor deposition (CVD) method. Response surface method (RSM) was employed to evaluate the effect of Ti species coating parameters on the photocatalytic activity, which was found to be affected by the furnace temperature, N 2 flow rate and influx time of precursor gas. Application of RSM successfully increased the photocatalytic efficiency of the Ti-MgAl-LDH in methylene blue photodegradation under UV irradiation, leading to improved economy of the process. According to the results from X-ray diffraction, scanning electron microscopy, Brunner-Emmet-Teller and Barrett-Joyner-Hallender, thermogravimetric and differential thermal analysis, UV-vis diffuse reflectance spectra analyses, the Ti species (TiO 2 or/and Ti 4+ ) were successfully coated on the MgAl-LDH matrix. The Ti species on the surface of the Ti-MgAl-LDH lead to a higher photocatalytic performance than commercial TiO 2 -P25. The results suggested that CVD method provided a new approach for the industrial preparation of Ti-coating MgAl-LDH material with good photocatalytic performances. Copyright © 2017. Published by Elsevier B.V.

  4. Organic Redox Species in Aqueous Flow Batteries: Redox Potentials, Chemical Stability and Solubility

    Science.gov (United States)

    Wedege, Kristina; Dražević, Emil; Konya, Denes; Bentien, Anders

    2016-01-01

    Organic molecules are currently investigated as redox species for aqueous low-cost redox flow batteries (RFBs). The envisioned features of using organic redox species are low cost and increased flexibility with respect to tailoring redox potential and solubility from molecular engineering of side groups on the organic redox-active species. In this paper 33, mainly quinone-based, compounds are studied experimentially in terms of pH dependent redox potential, solubility and stability, combined with single cell battery RFB tests on selected redox pairs. Data shows that both the solubility and redox potential are determined by the position of the side groups and only to a small extent by the number of side groups. Additionally, the chemical stability and possible degradation mechanisms leading to capacity loss over time are discussed. The main challenge for the development of all-organic RFBs is to identify a redox pair for the positive side with sufficiently high stability and redox potential that enables battery cell potentials above 1 V. PMID:27966605

  5. Organic Redox Species in Aqueous Flow Batteries: Redox Potentials, Chemical Stability and Solubility

    Science.gov (United States)

    Wedege, Kristina; Dražević, Emil; Konya, Denes; Bentien, Anders

    2016-12-01

    Organic molecules are currently investigated as redox species for aqueous low-cost redox flow batteries (RFBs). The envisioned features of using organic redox species are low cost and increased flexibility with respect to tailoring redox potential and solubility from molecular engineering of side groups on the organic redox-active species. In this paper 33, mainly quinone-based, compounds are studied experimentially in terms of pH dependent redox potential, solubility and stability, combined with single cell battery RFB tests on selected redox pairs. Data shows that both the solubility and redox potential are determined by the position of the side groups and only to a small extent by the number of side groups. Additionally, the chemical stability and possible degradation mechanisms leading to capacity loss over time are discussed. The main challenge for the development of all-organic RFBs is to identify a redox pair for the positive side with sufficiently high stability and redox potential that enables battery cell potentials above 1 V.

  6. Comparison of Mixing Calculations for Reacting and Non-Reacting Flows in a Cylindrical Duct

    Science.gov (United States)

    Oechsle, V. L.; Mongia, H. C.; Holdeman, J. D.

    1994-01-01

    A production 3-D elliptic flow code has been used to calculate non-reacting and reacting flow fields in an experimental mixing section relevant to a rich burn/quick mix/lean burn (RQL) combustion system. A number of test cases have been run to assess the effects of the variation in the number of orifices, mass flow ratio, and rich-zone equivalence ratio on the flow field and mixing rates. The calculated normalized temperature profiles for the non-reacting flow field agree qualitatively well with the normalized conserved variable isopleths for the reacting flow field indicating that non-reacting mixing experiments are appropriate for screening and ranking potential rapid mixing concepts. For a given set of jet momentum-flux ratio, mass flow ratio, and density ratio (J, MR, and DR), the reacting flow calculations show a reduced level of mixing compared to the non-reacting cases. In addition, the rich-zone equivalence ratio has noticeable effect on the mixing flow characteristics for reacting flows.

  7. Chemical and mechanical changes during leaf expansion of four woody species of dry Restinga woodland.

    Science.gov (United States)

    Schlindwein, C C D; Fett-Neto, A G; Dillenburg, L R

    2006-07-01

    Young leaves are preferential targets for herbivores, and plants have developed different strategies to protect them. This study aimed to evaluate different leaf attributes of presumed relevance in protection against herbivory in four woody species (Erythroxylum argentinum, Lithrea brasiliensis, Myrciaria cuspidata, and Myrsine umbellata), growing in a dry restinga woodland in southern Brazil. Evaluation of leaf parameters was made through single-point sampling of leaves (leaf mass per area and leaf contents of nitrogen, carbon, and pigments) at three developmental stages and through time-course sampling of expanding leaves (area and strength). Leaves of M. umbellata showed the highest leaf mass per area (LMA), the largest area, and the longest expansion period. On the other extreme, Myrc. cuspidata had the smallest LMA and leaf size, and the shortest expansion period. Similarly to L. brasiliensis, it displayed red young leaves. None of the species showed delayed-greening, which might be related to the high-irradiance growth conditions. Nitrogen contents reduced with leaf maturity and reached the highest values in the young leaves of E. argentinum and Myrc. cuspidata and the lowest in M. umbellata. Each species seems to present a different set of protective attributes during leaf expansion. Myrciaria cuspidata appears to rely mostly on chemical defences to protect its soft leaves, and anthocyanins might play this role at leaf youth, while M. umbellata seems to invest more on mechanical defences, even at early stages of leaf growth, as well as on a low allocation of nitrogen to the leaves. The other species display intermediate characteristics.

  8. Modeling and design of reacting systems with phase transfer catalysis

    DEFF Research Database (Denmark)

    Piccolo, Chiara; Hodges, George; Piccione, Patrick M.

    2011-01-01

    Issues related to the design of biphasic (liquid) catalytic reaction operations are discussed. A chemical system involving the reaction of an organic-phase soluble reactant (A) with an aqueous-phase soluble reactant (B) in the presence of phase transfer catalyst (PTC) is modeled and based on it......, some of the design issues related to improved reaction operation are analyzed. Since the solubility of the different forms of the PTC in the organic solvent affects ultimately the catalyst partition coefficients, therefore, the organic solvent plays an important role in the design of PTC-based reacting...

  9. On the stabilizing role of species diffusion in chemical enhanced oil recovery

    Science.gov (United States)

    Daripa, Prabir; Gin, Craig

    2015-11-01

    In this talk, the speaker will discuss a problem on the stability analysis related to the effect of species diffusion on stabilization of fingering in a Hele-Shaw model of chemical enhanced oil recovery. The formulation of the problem is motivated by a specific design principle of the immiscible interfaces in the hope that this will lead to significant stabilization of interfacial instabilities, there by improving oil recovery in the context of porous media flow. Testing the merits of this hypothesis poses some challenges which will be discussed along with some numerical results based on current formulation of this problem. Several open problems in this context will be discussed. This work is currently under progress. Supported by the grant NPRP 08-777-1-141 from the Qatar National Research Fund (a member of The Qatar Foundation).

  10. Extension of a hybrid particle-continuum method for a mixture of chemical species

    Science.gov (United States)

    Verhoff, Ashley M.; Boyd, Iain D.

    2012-11-01

    Due to the physical accuracy and numerical efficiency achieved by analyzing transitional, hypersonic flow fields with hybrid particle-continuum methods, this paper describes a Modular Particle-Continuum (MPC) method and its extension to include multiple chemical species. Considerations that are specific to a hybrid approach for simulating gas mixtures are addressed, including a discussion of the Chapman-Enskog velocity distribution function (VDF) for near-equilibrium flows, and consistent viscosity models for the individual CFD and DSMC modules of the MPC method. Representative results for a hypersonic blunt-body flow are then presented, where the flow field properties, surface properties, and computational performance are compared for simulations employing full CFD, full DSMC, and the MPC method.

  11. Assessment of local wood species used for the manufacture of cookware and the perception of chemical benefits and chemical hazards associated with their use in Kumasi, Ghana

    Directory of Open Access Journals (Sweden)

    Mensah John Kenneth

    2012-12-01

    Full Text Available Abstract Background Historical proven wood species have no reported adverse health effect associated with its past use. Different historical proven species have traditionally been used to manufacture different wooden food contact items. This study uses survey questionnaires to assess suppliers’, manufacturers’, retailers’ and consumers’ (end-users’ preferences for specific wood species, to examine the considerations that inform these preferences and to investigate the extent of awareness of the chemical benefits and chemical hazards associated with wooden food contact material use. Methods Through the combined use of a cross sectional approach and a case study design, 25 suppliers, 25 manufacturers, 25 retailers and 125 consumers (end-users of wooden food contact materials in four suburbs in Kumasi Metropolitan Area (Anloga junction, Ahinsan Bus Stop, Ahwia-Pankrono and Race Course and Ashanti Akyim Agogo in the Ashanti Akyim North District of the Ashanti Region were administered with closed ended questionnaires. The questionnaires were prepared in English, but local language, Twi, was used to translate and communicate the content of the questionnaire where necessary. Results Suppliers’, manufacturers’ and retailers’ preferences for specific wood species for most wooden cookware differed from that of consumers (end-users. But all respondent groups failed to indicate any awareness of chemical benefits or chemical hazards associated with either the choice of specific wood species for specific wooden cookware or with the general use of wooden food contact materials. The lack of appreciation of chemical benefits or hazards associated with active principles of wooden cookware led to heavy reliance of consumers (end-users on the wood density, price, attractive grain pattern and colour or on the judgement of retailers in their choice of specific species for a wooden cookware. Conclusion This study contributes some practical suggestions

  12. Chemical composition of essential oils from four Vietnamese species of piper (piperaceae).

    Science.gov (United States)

    Hieu, Le D; Thang, Tran D; Hoi, Tran M; Ogunwande, Isiaka A

    2014-01-01

    The chemical composition of essential oils from four Piper species, Piper retrofractum Vahl., P. boehmeriaefolium (Miq.) C. DC., P. sarmentosum Roxb., and P. maclurei Merr., were analysed by gas chromatography-flame ionization detector (GC-FID) and gas chromatography-mass spectrometry (GC-MS). Nineteen to sixty-four compounds representing 92.0%-98.4% of the total contents were identified in the oil samples. The major constituents identified in P. retrofractum leaf oil were benzyl benzoate (14.4%), myrcene (14.4%), bicycloelemene (9.9%), bicyclogermacrene (7.0%) and β-caryophyllene (5.3%). On the other hand, the main constituents of P. boehmeriaefolium were α-copaene (28.3%), α-pinene (7.4%) and 1, 8-cineole (5.7%). P. sarmentosum showed a very different chemical profile characterized mainly by aromatic compounds and devoid of monoterpene hydrocarbons. The major constituents were benzyl benzoate (49.1%), benzyl alcohol (17.9%), 2-hydroxy-benzoic acid phenylmethyl ester (10.0%) and 2-butenyl-benzene (7.9%). The leaf of P. maclurei was characterized by higher amount of (E)-cinnamic acid (37.4%) and (E)-nerolidol (19.4%). Moreover, (Z)-9-octadecanoic acid methyl ester (28.0%), (E)-cinnamyl acetate (17.2%), phytol (12.2%) and (E)-cinnamaldehyde (8.8%) were the major compounds identified in the stem oil.

  13. Sea Cucumber Glycosides: Chemical Structures, Producing Species and Important Biological Properties.

    Science.gov (United States)

    Mondol, Muhammad Abdul Mojid; Shin, Hee Jae; Rahman, M Aminur; Islam, Mohamad Tofazzal

    2017-10-17

    Sea cucumbers belonging to echinoderm are traditionally used as tonic food in China and other Asian countries. They produce abundant biologically active triterpene glycosides. More than 300 triterpene glycosides have been isolated and characterized from various species of sea cucumbers, which are classified as holostane and nonholostane depending on the presence or absence of a specific structural unit γ(18,20)-lactone in the aglycone. Triterpene glycosides contain a carbohydrate chain up to six monosaccharide units mainly consisting of d-xylose, 3-O-methy-d-xylose, d-glucose, 3-O-methyl-d-glucose, and d-quinovose. Cytotoxicity is the common biological property of triterpene glycosides isolated from sea cucumbers. Besides cytotoxicity, triterpene glycosides also exhibit antifungal, antiviral and hemolytic activities. This review updates and summarizes our understanding on diverse chemical structures of triterpene glycosides from various species of sea cucumbers and their important biological activities. Mechanisms of action and structural-activity relationships (SARs) of sea cucumber glycosides are also discussed briefly.

  14. Anti-Inflammatory Properties and Chemical Characterization of the Essential Oils of Four Citrus Species.

    Science.gov (United States)

    Amorim, Jorge Luis; Simas, Daniel Luiz Reis; Pinheiro, Mariana Martins Gomes; Moreno, Daniela Sales Alviano; Alviano, Celuta Sales; da Silva, Antonio Jorge Ribeiro; Fernandes, Patricia Dias

    2016-01-01

    Citrus fruits have potential health-promoting properties and their essential oils have long been used in several applications. Due to biological effects described to some citrus species in this study our objectives were to analyze and compare the phytochemical composition and evaluate the anti-inflammatory effect of essential oils (EO) obtained from four different Citrus species. Mice were treated with EO obtained from C. limon, C. latifolia, C. aurantifolia or C. limonia (10 to 100 mg/kg, p.o.) and their anti-inflammatory effects were evaluated in chemical induced inflammation (formalin-induced licking response) and carrageenan-induced inflammation in the subcutaneous air pouch model. A possible antinociceptive effect was evaluated in the hot plate model. Phytochemical analyses indicated the presence of geranial, limonene, γ-terpinene and others. EOs from C. limon, C. aurantifolia and C. limonia exhibited anti-inflammatory effects by reducing cell migration, cytokine production and protein extravasation induced by carrageenan. These effects were also obtained with similar amounts of pure limonene. It was also observed that C. aurantifolia induced myelotoxicity in mice. Anti-inflammatory effect of C. limon and C. limonia is probably due to their large quantities of limonene, while the myelotoxicity observed with C. aurantifolia is most likely due to the high concentration of citral. Our results indicate that these EOs from C. limon, C. aurantifolia and C. limonia have a significant anti-inflammatory effect; however, care should be taken with C. aurantifolia.

  15. Anti-Inflammatory Properties and Chemical Characterization of the Essential Oils of Four Citrus Species.

    Directory of Open Access Journals (Sweden)

    Jorge Luis Amorim

    Full Text Available Citrus fruits have potential health-promoting properties and their essential oils have long been used in several applications. Due to biological effects described to some citrus species in this study our objectives were to analyze and compare the phytochemical composition and evaluate the anti-inflammatory effect of essential oils (EO obtained from four different Citrus species. Mice were treated with EO obtained from C. limon, C. latifolia, C. aurantifolia or C. limonia (10 to 100 mg/kg, p.o. and their anti-inflammatory effects were evaluated in chemical induced inflammation (formalin-induced licking response and carrageenan-induced inflammation in the subcutaneous air pouch model. A possible antinociceptive effect was evaluated in the hot plate model. Phytochemical analyses indicated the presence of geranial, limonene, γ-terpinene and others. EOs from C. limon, C. aurantifolia and C. limonia exhibited anti-inflammatory effects by reducing cell migration, cytokine production and protein extravasation induced by carrageenan. These effects were also obtained with similar amounts of pure limonene. It was also observed that C. aurantifolia induced myelotoxicity in mice. Anti-inflammatory effect of C. limon and C. limonia is probably due to their large quantities of limonene, while the myelotoxicity observed with C. aurantifolia is most likely due to the high concentration of citral. Our results indicate that these EOs from C. limon, C. aurantifolia and C. limonia have a significant anti-inflammatory effect; however, care should be taken with C. aurantifolia.

  16. Evaluation of Chemical Composition and Antileishmanial and Antituberculosis Activities of Essential Oils of Piper Species

    Directory of Open Access Journals (Sweden)

    Karine Zanoli Bernuci

    2016-12-01

    Full Text Available Essential oils from fresh Piperaceae leaves were obtained by hydrodistillation and analyzed by gas chromatography mass spectrometry (GC–MS, and a total of 68 components were identified. Principal components analysis results showed a chemical variability between species, with sesquiterpene compounds predominating in the majority of species analyzed. The composition of the essential oil of Piper mosenii was described for the first time. The cytotoxicity of the essential oils was evaluated in peritoneal macrophages and the oils of P. rivinoides, P. arboretum, and P. aduncum exhibited the highest values, with cytotoxic concentration at 50% (CC50 > 200 µg/mL. Both P. diospyrifolium and P. aduncum displayed activity against Leishmania amazonensis, and were more selective for the parasite than for the macrophages, with a selectivity index (SI of 2.35 and >5.52, respectively. These SI values were greater than the 1 for the standard drug pentamidine. The antileishmanial activity of the essential oils of P. diospyrifolium and P. aduncum was described for the first time. P. rivinoides, P. cernuum, and P. diospyrifolium displayed moderate activity against the Mycobacterium tuberculosis H37Rv bacillus, with a minimum inhibitory concentration (MIC of 125 µg/mL. These results are relevant and suggests their potential for therapeutic purposes. Nevertheless, further studies are required to explain the exact mechanism of action of these essential oils.

  17. Evaluation of Chemical Composition and Antileishmanial and Antituberculosis Activities of Essential Oils of Piper Species.

    Science.gov (United States)

    Bernuci, Karine Zanoli; Iwanaga, Camila Cristina; Fernandez-Andrade, Carla Maria Mariano; Lorenzetti, Fabiana Brusco; Torres-Santos, Eduardo Caio; Faiões, Viviane Dos Santos; Gonçalves, José Eduardo; do Amaral, Wanderlei; Deschamps, Cícero; Scodro, Regiane Bertin de Lima; Cardoso, Rosilene Fressatti; Baldin, Vanessa Pietrowski; Cortez, Diógenes Aparício Garcia

    2016-12-12

    Essential oils from fresh Piperaceae leaves were obtained by hydrodistillation and analyzed by gas chromatography mass spectrometry (GC-MS), and a total of 68 components were identified. Principal components analysis results showed a chemical variability between species, with sesquiterpene compounds predominating in the majority of species analyzed. The composition of the essential oil of Piper mosenii was described for the first time. The cytotoxicity of the essential oils was evaluated in peritoneal macrophages and the oils of P. rivinoides , P. arboretum , and P. aduncum exhibited the highest values, with cytotoxic concentration at 50% (CC 50 ) > 200 µg/mL. Both P. diospyrifolium and P. aduncum displayed activity against Leishmania amazonensis , and were more selective for the parasite than for the macrophages, with a selectivity index (SI) of 2.35 and >5.52, respectively. These SI values were greater than the 1 for the standard drug pentamidine. The antileishmanial activity of the essential oils of P. diospyrifolium and P. aduncum was described for the first time. P. rivinoides, P. cernuum , and P. diospyrifolium displayed moderate activity against the Mycobacterium tuberculosis H 37 Rv bacillus, with a minimum inhibitory concentration (MIC) of 125 µg/mL. These results are relevant and suggests their potential for therapeutic purposes. Nevertheless, further studies are required to explain the exact mechanism of action of these essential oils.

  18. Development of Implicit Compact Methods for Chemically Reacting Flows

    Science.gov (United States)

    2009-02-28

    NSP_P), DKt (NSP_P), & ! stoichiometric coeffs (# mols produced/destroyed) & NUK(NSP_P), & ! mass coeffs: NUK(k)*WK(k) & NUKWK(NSP_P), & & WK... DKt UC UCr wc WCz NUK NUKWK ! (nu_0 sstoich Yfuel Yox Yfuel_F Yox_A Z PHI omega SOURCE q HEAT = SpecificHeat(T) = 0 .do...RHO*T) dot_product(DK,YKr) ! correction vel. for mass conservation dot_product(DK,YKrr)+dot_product(( DKt *Tr),YKr) dot_product(DK,YKz) ! correction

  19. Chemical and morphological characteristics of key tree species of the Carpathian Mountains

    International Nuclear Information System (INIS)

    Mankovska, Blanka; Godzik, Barbara; Badea, Ovidiu; Shparyk, Yuri; Moravcik, Pavel

    2004-01-01

    Concentrations of Al, B, Ca, Cu, Fe, K, Mg, Mn, N, Na, P, S and Zn in the foliage of white fir (Abies alba), Norway spruce (Picea abies) and common beech (Fagus sylvatica) from 25 sites of the Carpathian Mts. forests (Czech Republic, Poland, Romania, Slovakia and Ukraine) are discussed in a context of their limit values. S/N ratio was different from optimum in 90% of localities when compared with the European limit values. Likewise we found increase of Fe and Cu concentrations compared with their background levels in 100% of locations. Mn concentrations were increased in 76% of localities. Mn mobilization values indicate the disturbance of physiological balance leading to the change of the ratio with Fe. SEM-investigation of foliage waxes from 25 sites in the Carpathian Mts. showed, that there is a statistically significant difference in mean wax quality. Epistomatal waxes were damaged as indicated by increased development of net and amorphous waxes. The most damaged stomata in spruce needles were from Yablunitsa, Synevir and Brenna; in fir needles from Stoliky, and in beech leaves from Mala Fatra, Morske Oko and Beregomet. Spruce needles in the Carpathian Mts. had more damaged stomata than fir needles and beech leaves. Spruce seems to be the most sensitive tree species to environmental stresses including air pollution in forests of the Carpathian Mountains. Foliage surfaces of three forest tree species contained Al, Si, Ca, Fe, Mg, K, Cl, Mn, Na, Ni and Ti in all studied localities. Presence of nutrition elements (Ca, Fe, Mg, K and Mn) on foliage surface hinders opening and closing stomata and it is not physiologically usable for tree species. - Chemical composition of foliage and structure of epicuticular waxes indicated phytotoxic effects of air pollution in many forest sites of the Carpathian Mountains

  20. Evidence for chemical interference effect of an allelopathic plant on neighboring plant species: A field study.

    Directory of Open Access Journals (Sweden)

    Antonio I Arroyo

    Full Text Available Many studies have reported the phytotoxicity of allelopathic compounds under controlled conditions. However, more field studies are required to provide realistic evidences for the significance of allelopathic interference in natural communities. We conducted a 2-years field experiment in a semiarid plant community (NE Spain. Specifically, we planted juvenile individuals and sowed seeds of Salsola vermiculata L., Lygeum spartum L. and Artemisia herba-alba Asso. (three co-dominant species in the community beneath adult individuals of the allelopathic shrub A. herba-alba, and assessed the growth, vitality, seed germination and seedling survival of those target species with and without the presence of chemical interference by the incorporation of activated carbon (AC to the soil. In addition, juveniles and seeds of the same three target species were planted and sown beneath the canopy of adults of S. vermiculata (a shrub similar to A. herba-alba, but non-allelopathic and in open bare soil to evaluate whether the allelopathic activity of A. herba-alba modulates the net outcome of its interactions with neighboring plants under contrasting abiotic stress conditions. We found that vitality of A. herba-alba juveniles was enhanced beneath A. herba-alba individuals when AC was present. Furthermore, we found that the interaction outcome in A. herba-alba microsite was neutral, whereas a positive outcome was found for S. vermiculata microsite, suggesting that allelopathy may limit the potential facilitative effects of the enhanced microclimatic conditions in A. herba-alba microsite. Yet, L. spartum juveniles were facilitated in A. herba-alba microsite. The interaction outcome in A. herba-alba microsite was positive under conditions of very high abiotic stress, indicating that facilitative interactions predominated over the interference of allelopathic plants under those conditions. These results highlight that laboratory studies can overestimate the

  1. Evidence for chemical interference effect of an allelopathic plant on neighboring plant species: A field study.

    Science.gov (United States)

    Arroyo, Antonio I; Pueyo, Yolanda; Giner, M Luz; Foronda, Ana; Sanchez-Navarrete, Pedro; Saiz, Hugo; Alados, Concepción L

    2018-01-01

    Many studies have reported the phytotoxicity of allelopathic compounds under controlled conditions. However, more field studies are required to provide realistic evidences for the significance of allelopathic interference in natural communities. We conducted a 2-years field experiment in a semiarid plant community (NE Spain). Specifically, we planted juvenile individuals and sowed seeds of Salsola vermiculata L., Lygeum spartum L. and Artemisia herba-alba Asso. (three co-dominant species in the community) beneath adult individuals of the allelopathic shrub A. herba-alba, and assessed the growth, vitality, seed germination and seedling survival of those target species with and without the presence of chemical interference by the incorporation of activated carbon (AC) to the soil. In addition, juveniles and seeds of the same three target species were planted and sown beneath the canopy of adults of S. vermiculata (a shrub similar to A. herba-alba, but non-allelopathic) and in open bare soil to evaluate whether the allelopathic activity of A. herba-alba modulates the net outcome of its interactions with neighboring plants under contrasting abiotic stress conditions. We found that vitality of A. herba-alba juveniles was enhanced beneath A. herba-alba individuals when AC was present. Furthermore, we found that the interaction outcome in A. herba-alba microsite was neutral, whereas a positive outcome was found for S. vermiculata microsite, suggesting that allelopathy may limit the potential facilitative effects of the enhanced microclimatic conditions in A. herba-alba microsite. Yet, L. spartum juveniles were facilitated in A. herba-alba microsite. The interaction outcome in A. herba-alba microsite was positive under conditions of very high abiotic stress, indicating that facilitative interactions predominated over the interference of allelopathic plants under those conditions. These results highlight that laboratory studies can overestimate the significance of

  2. Divergent chemical cues elicit seed collecting by ants in an obligate multi-species mutualism in lowland Amazonia.

    Directory of Open Access Journals (Sweden)

    Elsa Youngsteadt

    2010-12-01

    Full Text Available In lowland Amazonian rainforests, specific ants collect seeds of several plant species and cultivate them in arboreal carton nests, forming species-specific symbioses called ant-gardens (AGs. In this obligate mutualism, ants depend on the plants for nest stability and the plants depend on ant nests for substrate and nutrients. AG ants and plants are abundant, dominant members of lowland Amazonian ecosystems, but the cues ants use to recognize the seeds are poorly understood. To address the chemical basis of the ant-seed interaction, we surveyed seed chemistry in nine AG species and eight non-AG congeners. We detected seven phenolic and terpenoid volatiles common to seeds of all or most of the AG species, but a blend of the shared compounds was not attractive to the AG ant Camponotus femoratus. We also analyzed seeds of three AG species (Anthurium gracile, Codonanthe uleana, and Peperomia macrostachya using behavior-guided fractionation. At least one chromatographic fraction of each seed extract elicited retrieval behavior in C. femoratus, but the active fractions of the three plant species differed in polarity and chemical composition, indicating that shared compounds alone did not explain seed-carrying behavior. We suggest that the various AG seed species must elicit seed-carrying with different chemical cues.

  3. Enolonium Species-Umpoled Enolates

    DEFF Research Database (Denmark)

    Arava, Shlomy; Kumar, Jayprakash N.; Maksymenko, Shimon

    2017-01-01

    Enolonium species/iodo(III) enolates of carbonyl compounds have been suggested to be intermediates in a wide variety of hypervalent iodine induced chemical transformations of ketones, including α-C-O, α-C-N, α-C-C, and alpha-carbon- halide bond formation, but they have never been characterized. We...... report that these elusive umpoled enolates may be made as discrete species that are stable for several minutes at-78 degrees C, and report the first spectroscopic identification of such species. It is shown that enolonium species are direct intermediates in C-O, C-N, C-Cl, and C-C bond forming reactions....... Our results open up chemical space for designing a variety of new transformations. We showcase the ability of enolonium species to react with prenyl, crotyl, cinnamyl, and allyl silanes with absolute regioselectivity in up to 92% yield....

  4. A constitutive theory of reacting electrolyte mixtures

    Science.gov (United States)

    Costa Reis, Martina; Wang, Yongqi; Bono Maurizio Sacchi Bassi, Adalberto

    2013-11-01

    A constitutive theory of reacting electrolyte mixtures is formulated. The intermolecular interactions among the constituents of the mixture are accounted for through additional freedom degrees to each constituent of the mixture. Balance equations for polar reacting continuum mixtures are accordingly formulated and a proper set of constitutive equations is derived with basis in the Müller-Liu formulation of the second law of thermodynamics. Moreover, the non-equilibrium and equilibrium responses of the reacting mixture are investigated in detail by emphasizing the inner and reactive structures of the medium. From the balance laws and constitutive relations, the effects of molecular structure of constituents upon the fluid flow are studied. It is also demonstrated that the local thermodynamic equilibrium state can be reached without imposing that the set of independent constitutive variables is time independent, neither spatially homogeneous nor null. The resulting constitutive relations presented throughout this work are of relevance to many practical applications, such as swelling of clays, developing of bio and polymeric membranes, and use of electrorheological fluids in industrial processes. The first author acknowledges financial support from National Counsel of Technological and Scientific Development (CNPq) and German Academic Exchange Service (DAAD).

  5. The physico-chemical radioiodine species in the exhaust air of a pressurized water reactor (PWR2)

    International Nuclear Information System (INIS)

    Deuber, H.

    1981-12-01

    In a German pressurized water reactor, the physico-chemical 131 I species were determined in the plant exhaust and in the individual exhausts during 6 months. These measurements aimed in particular at determining the percentage and the source of the radiologically decisive elemental 131 I released to the environment. The retention of the 131 I species by iodine filters was also investigated. 20 to 30% of the 131 I discharged with the plant exhaust consisted of elemental iodine. This was largely released with the unfiltered exhaust from the chemical laboratory hoods and from the annular compartment. (orig.) [de

  6. Chemical Analysis and Biological Activity of the Essential Oils of Two Endemic Soqotri Commiphora Species

    Directory of Open Access Journals (Sweden)

    Wulf Schultze

    2010-02-01

    Full Text Available The barks of two endemic Commiphora species namely, Commiphora ornifolia (Balf.f. Gillett and Commiphora parvifolia Engl., were collected from Soqotra Island in Yemen and their essential oils were obtained by hydrodistillation. The chemical composition of both oils was investigated by GC and GC-MS. Moreover, the essential oils were evaluated for their antimicrobial activity against two Gram-positive bacteria, two Gram-negative bacteria and one yeast species by using a broth micro-dilution assay for minimum inhibitory concentrations (MIC and for their antioxidant activity by measuring the DPPH radical scavenging activity. A total of 45 constituents of C. ornifolia (85.6% and 44 constituents of C. parvifolia (87.1% were identified. The oil of C. ornifolia was characterized by a high content of oxygenated monoterpenes (56.3%, of which camphor (27.3%, α-fenchol (15.5%, fenchone (4.4% and borneol (2.9% were identified as the main components. High contents of oxygenated sesquiterpenes (36.1% and aliphatic acids (22.8% were found in C. parvifolia oil, in which caryophyllene oxide (14.2%, β-eudesmol (7.7%, bulnesol (5.7%, T-cadinol (3.7% and hexadecanoic acid (18.4% predominated. The results of the antimicrobial assay showed that both oils exhibited moderate to high antibacterial activity especially against Gram-positive bacteria. C. ornifolia oil was the most active. In addition, the DPPH-radical scavenging assay exhibited only weak antioxidant activities for both oils at the high concentration tested.

  7. Chemical variation in a dominant tree species: population divergence, selection and genetic stability across environments.

    Directory of Open Access Journals (Sweden)

    Julianne M O'Reilly-Wapstra

    Full Text Available Understanding among and within population genetic variation of ecologically important plant traits provides insight into the potential evolutionary processes affecting those traits. The strength and consistency of selection driving variability in traits would be affected by plasticity in differences among genotypes across environments (G×E. We investigated population divergence, selection and environmental plasticity of foliar plant secondary metabolites (PSMs in a dominant tree species, Eucalyptus globulus. Using two common garden trials we examined variation in PSMs at multiple genetic scales; among 12 populations covering the full geographic range of the species and among up to 60 families within populations. Significant genetic variation in the expression of many PSMs resides both among and within populations of E. globulus with moderate (e.g., sideroxylonal A h(2op = 0.24 to high (e.g., macrocarpal G h(2op = 0.48 narrow sense heritabilities and high coefficients of additive genetic variation estimated for some compounds. A comparison of Qst and Fst estimates suggest that variability in some of these traits may be due to selection. Importantly, there was no genetic by environment interaction in the expression of any of the quantitative chemical traits despite often significant site effects. These results provide evidence that natural selection has contributed to population divergence in PSMs in E. globulus, and identifies the formylated phloroglucinol compounds (particularly sideroxylonal and a dominant oil, 1,8-cineole, as candidates for traits whose genetic architecture has been shaped by divergent selection. Additionally, as the genetic differences in these PSMs that influence community phenotypes is stable across environments, the role of plant genotype in structuring communities is strengthened and these genotypic differences may be relatively stable under global environmental changes.

  8. Chemical Composition and Biological Activity of Essential Oils from Different Species of Piper from Panama.

    Science.gov (United States)

    Santana, Ana I; Vila, Roser; Cañigueral, Salvador; Gupta, Mahabir P

    2016-07-01

    The chemical composition of leaf essential oils from 11 species of Piper from Panama was analyzed by a combination GC-FID and GC-MS procedures. Six of them had sesquiterpene hydrocarbons as major constituents, three were characterized by monoterpene hydrocarbons, one by a diterpene, and one by a phenylpropanoid, dillapiole. The main components identified in each species were: cembratrienol (25.4 %) in Piper augustum; β-pinene (26.6 %) in Piper corrugatum; α-pinene (19.4 %) in Piper curtispicum; trans-β-farnesene (63.7 %) in Piper darienense; p-cymene (43.9 %) in Piper grande; dillapiole (57.7 %) in Piper hispidum; linalool (14.5 %), α-phellandrene (13.8 %), and limonene (12.2 %) in Piper jacquemontianum; β-caryophyllene (45.2 %) in Piper longispicum; linalool (16.5 %), α-phellandrene (11.8 %), limonene (11.4 %), and p-cymene (9.0 %) in Piper multiplinervium; β-selinene (19.0 %), β-elemene (16.1 %), and α-selinene (15.5 %) in Piper reticulatum; and germacrene D (19.7 %) in Piper trigonum. The essential oils of P. hispidum and P. longispicum at a concentration of 250 µg/mL showed larvicidal activity against Aedes aegypti, while the oils from P. curtispicum, P. multiplinervium, P. reticulatum, and P. trigonum were inactive (LC100 ≥ 500 µg/mL). The essential oils of P. grande, P. jacquemontianum, and P. multiplinervium showed no significant antifungal activity (MIC > 250 µg/mL) against several yeasts and filamentous fungal strains. Georg Thieme Verlag KG Stuttgart · New York.

  9. Chemical Composition, Nitrogen Fractions and Amino Acids Profile of Milk from Different Animal Species

    Directory of Open Access Journals (Sweden)

    Saima Rafiq

    2016-07-01

    Full Text Available Milk composition is an imperative aspect which influences the quality of dairy products. The objective of study was to compare the chemical composition, nitrogen fractions and amino acids profile of milk from buffalo, cow, sheep, goat, and camel. Sheep milk was found to be highest in fat (6.82%±0.04%, solid-not-fat (11.24%±0.02%, total solids (18.05%±0.05%, protein (5.15%±0.06% and casein (3.87%±0.04% contents followed by buffalo milk. Maximum whey proteins were observed in camel milk (0.80%±0.03%, buffalo (0.68%±0.02% and sheep (0.66%±0.02% milk. The non-protein-nitrogen contents varied from 0.33% to 0.62% among different milk species. The highest r-values were recorded for correlations between crude protein and casein in buffalo (r = 0.82, cow (r = 0.88, sheep (r = 0.86 and goat milk (r = 0.98. The caseins and whey proteins were also positively correlated with true proteins in all milk species. A favorable balance of branched-chain amino acids; leucine, isoleucine, and valine were found both in casein and whey proteins. Leucine content was highest in cow (108±2.3 mg/g, camel (96±2.2 mg/g and buffalo (90±2.4 mg/g milk caseins. Maximum concentrations of isoleucine, phenylalanine, and histidine were noticed in goat milk caseins. Glutamic acid and proline were dominant among non-essential amino acids. Conclusively, current exploration is important for milk processors to design nutritious and consistent quality end products.

  10. Chemically engineering ligand selectivity at the free fatty acid receptor 2 based on pharmacological variation between species orthologs

    DEFF Research Database (Denmark)

    Hudson, Brian D; Christiansen, Elisabeth; Tikhonova, Irina G

    2012-01-01

    When it is difficult to develop selective ligands within a family of related G-protein-coupled receptors (GPCRs), chemically engineered receptors activated solely by synthetic ligands (RASSLs) are useful alternatives for probing receptor function. In the present work, we explored whether a RASSL...... on this receptor and demonstrates that exploitation of pharmacological variation between species orthologs is a powerful method to generate novel chemically engineered GPCRs.-Hudson, B. D., Christiansen, E., Tikhonova, I. G., Grundmann, M., Kostenis, E., Adams, D. R., Ulven, T., Milligan, G. Chemically engineering...

  11. Ethnopharmacological and Chemical Characterization of Salvia Species Used in Valencian Traditional Herbal Preparations

    Directory of Open Access Journals (Sweden)

    Vanessa Martínez-Francés

    2017-07-01

    Full Text Available In Valencia Region (Spain, some wild and cultivated sages are used for medicinal purposes. Among them, Salvia officinalis subsp. lavandulifolia (SL is widely employed and known for production of Spanish sage oil and herbal products. Nevertheless, it shares the market with S. blancoana subsp. mariolensis (SB and, to a lesser extent, with their hybrid S. x hegelmaieri (SH. The knowledge on these two species is far low and confusion between them is possible. The aim of the present paper is to improve the ethnopharmacological, morphological and chemical knowledge of these sages, and to contribute to setting up quality specifications for improving identification and distinction from other Salvia species, such as, S. officinalis subsp. officinalis, S. x auriculata and S. microphylla var. microphylla. Samples were collected in Valencia Region and surrounding mountain areas during the ethnopharmacological field work. Twenty-nine medicinal uses were reported for SL, 13 of them being also recorded for SB. Of particular interest is a homemade liquor, used as digestive and known as “salvieta,” which is mainly prepared with SB. The macro- and microscopic characters are insufficient for identification of cut, crushed or powdered material. The study of the essential oil and a HPTLC (High Performance Thin Layer Chromatography fingerprint of their extracts could help to distinguish SB from the other sages. The essential oil from dried aerial parts of SB (content: 1.8–4.5% was characterized by GC-FID (Gas Chromatography with Flame Ionization Detector and GC-MS (Gas Chromatography coupled to Mass Spectrometry showing a composition close to that currently accepted for Spanish sage essential oil in the European Pharmacopoeia, ISO (International Standard Organization and UNE (Una Norma Española standards, with 1,8-cineole (13.7–45.7% and camphor (12.1–28.6% as major constituents. HPTLC methods, based on the analysis of hydroalcoholic and dichloromethane

  12. Chemical compositions of essential oils from two Artemisia species used in Mongolian traditional medicine

    Directory of Open Access Journals (Sweden)

    Javzmaa N

    2018-02-01

    Full Text Available Essential oils of aromatic and medicinal plants generally have a diverse range of activities because they possess many active constituents that work through a several modes of action. Artemisia, the largest genus of the family Asteraceae, has a number of effects against human and plant diseases. The main purpose of the present study was to investigate chemical compositions of essential oils of two Artemisia species, Artemisia palustris L and Artemisia sericea Weber ex Stechm from the Mongolian steppe zone using gas chromatography and gas chromatography-mass spectrometry. The essential oil of A.palustris was characterized by the presence of monoterpene hydrocarbons such as  trans-β-ocimene (59.1%, cis-β-ocimene (11.6% and myrcene (7.1%, while the oil of A.sericea was dominated by the presence of three oxygenated monoterpenoids as 1,8-cineole (25.8%, borneol (22.5% and camphor (18.8% which are used for preparation of a fragrance and medicinal products.

  13. MORPHO-CHEMICAL DESCRIPTION AND ANTIMICROBIAL ACTIVITY OF DIFFERENT OCIMUM SPECIES

    Directory of Open Access Journals (Sweden)

    KAKARAPARTHI PANDU SASTRY

    2012-12-01

    Full Text Available Basil is a popular medicinal and culinary herb, and its essential oils have been used extensively for many years in food products, perfumery, dental and oral products. Basil essential oils and their principal constituents were found to exhibit antimicrobial activity against a wide range of Gram-negative and Gram-positive bacteria, yeast, and mould. The essential oils obtained from aerial parts of three different species of Ocimum comprising twenty one germplasm lines were investigated for their essential oil composition and antimicrobial activity during 2010. Essential oils from seventeen germplasm lines in Ocimum basilicum and two each in Ocimum tenuiflorum and Ocimum gratissimum were investigated for anti-microbial activity against four bacterial strains (Staphylococcus aureus, Bacillus sps., Escherichia coli and Pseudomonas aeruginosa. The morpho-chemotypes exhibited wide variability for morphological and chemical traits. Anti-bacterial activity was found to be high for Staphylococcus aureus, moderate for Escherichia coli, low for Bacillus and Pseudomonas aeruginosa was highly resistant. The essential oils of Pale Green-Broad Leaves (O. basilicum and CIM Ayu (O. gratissimum exhibited significant antibacterial activity against both S. aureus and E. coli signifying them promising for anti-bacterial activity. No relationship was observed between chemotype specificity and anti-bacterial activity, indicating that apart from major components of essential oil, minor components and other factors may be responsible for anti-microbial activities.

  14. Chemical Composition and Acetylcholinesterase Inhibitory Activity of Essential Oils from Piper Species.

    Science.gov (United States)

    Xiang, Cai-Peng; Han, Jia-Xin; Li, Xing-Cong; Li, Yun-Hui; Zhang, Yi; Chen, Lin; Qu, Yan; Hao, Chao-Yun; Li, Hai-Zhou; Yang, Chong-Ren; Zhao, San-Jun; Xu, Min

    2017-05-10

    The essential oils (EOs) derived from aromatic plants such as Piper species are considered to play a role in alleviating neuronal ailments that are associated with inhibition of acetylcholinesterase (AChE). The chemical compositions of 23 EOs prepared from 16 Piper spp. were analyzed by both gas chromatography with a flame ionization detector (GC-FID) and gas chromatography-mass spectrometry (GC-MS). A total of 76 compounds were identified in the EOs from the leaves and stems of 19 samples, while 30 compounds were detected in the EOs from the fruits of four samples. Sesquiterpenes and phenylpropanoids were found to be rich in these EOs, of which asaricin, caryophyllene, caryophyllene oxide, isospathulenol, (+)-spathulenol, and β-bisabolene are the major constituents. The EOs from the leaves and stems of Piper austrosinense, P. puberulum, P. flaviflorum, P. betle, and P. hispidimervium showed strong AChE inhibitory activity with IC 50 values in the range of 1.51 to 13.9 mg/mL. A thin-layer chromatography (TLC) bioautography assay was employed to identify active compound(s) in the most active EO from P. hispidimervium. The active compound was isolated and identified as asaricin, which gave an IC 50 value of 0.44 ± 0.02 mg/mL against AChE, comparable to galantamine with an IC 50 0.15 ± 0.01 mg/mL.

  15. Chemical sanitizers to control biofilms formed by two Pseudomonas species on stainless steel surface

    Directory of Open Access Journals (Sweden)

    Danila Soares Caixeta

    2012-03-01

    Full Text Available The biofilm formation of Pseudomonas aeruginosa and Pseudomonas fluorescens on AISI 304 stainless steel in the presence of reconstituted skim milk under different temperatures was conducted, and the potential of three chemical sanitizers in removing the mono-species biofilms formed was compared. Pseudomonas aeruginosa cultivated in skim milk at 28 °C presented better growth rate (10.4 log CFU.mL-1 when compared with 3.7 and 4.2 log CFU.mL-1 for P. aeruginosa and P. fluorescens cultivated at 7 °C, respectively. Pseudomonas aeruginosa formed biofilm when cultivated at 28 °C. However, only the adhesion of P. aeruginosa and P. fluorescens was observed when incubated at 7 °C. The sodium dichloroisocyanurate was the most efficient sanitizer in the reduction of the adhered P. aeruginosa cells at 7 and 28 °C and those on the biofilm, respectively. The hydrogen peroxide was more effective in the reduction of adhered cells of P. fluorescens at 7 °C.

  16. Discrimination and chemical phylogenetic study of seven species of Dendrobium using infrared spectroscopy combined with cluster analysis

    Science.gov (United States)

    Luo, Congpei; He, Tao; Chun, Ze

    2013-04-01

    Dendrobium is a commonly used and precious herb in Traditional Chinese Medicine. The high biodiversity of Dendrobium and the therapeutic needs require tools for the correct and fast discrimination of different Dendrobium species. This study investigates Fourier transform infrared spectroscopy followed by cluster analysis for discrimination and chemical phylogenetic study of seven Dendrobium species. Despite the general pattern of the IR spectra, different intensities, shapes, peak positions were found in the IR spectra of these samples, especially in the range of 1800-800 cm-1. The second derivative transformation and alcoholic extracting procedure obviously enlarged the tiny spectral differences among these samples. The results indicated each Dendrobium species had a characteristic IR spectra profile, which could be used to discriminate them. The similarity coefficients among the samples were analyzed based on their second derivative IR spectra, which ranged from 0.7632 to 0.9700, among the seven Dendrobium species, and from 0.5163 to 0.9615, among the ethanol extracts. A dendrogram was constructed based on cluster analysis the IR spectra for studying the chemical phylogenetic relationships among the samples. The results indicated that D. denneanum and D. crepidatum could be the alternative resources to substitute D. chrysotoxum, D. officinale and D. nobile which were officially recorded in Chinese Pharmacopoeia. In conclusion, with the advantages of high resolution, speediness and convenience, the experimental approach can successfully discriminate and construct the chemical phylogenetic relationships of the seven Dendrobium species.

  17. MP Salsa: a finite element computer program for reacting flow problems. Part 1--theoretical development

    Energy Technology Data Exchange (ETDEWEB)

    Shadid, J.N.; Moffat, H.K.; Hutchinson, S.A.; Hennigan, G.L.; Devine, K.D.; Salinger, A.G.

    1996-05-01

    The theoretical background for the finite element computer program, MPSalsa, is presented in detail. MPSalsa is designed to solve laminar, low Mach number, two- or three-dimensional incompressible and variable density reacting fluid flows on massively parallel computers, using a Petrov-Galerkin finite element formulation. The code has the capability to solve coupled fluid flow, heat transport, multicomponent species transport, and finite-rate chemical reactions, and to solver coupled multiple Poisson or advection-diffusion- reaction equations. The program employs the CHEMKIN library to provide a rigorous treatment of multicomponent ideal gas kinetics and transport. Chemical reactions occurring in the gas phase and on surfaces are treated by calls to CHEMKIN and SURFACE CHEMKIN, respectively. The code employs unstructured meshes, using the EXODUS II finite element data base suite of programs for its input and output files. MPSalsa solves both transient and steady flows by using fully implicit time integration, an inexact Newton method and iterative solvers based on preconditioned Krylov methods as implemented in the Aztec solver library.

  18. Improving the chemical compatibility of sealing glass for solid oxide fuel cells: Blocking the reactive species by controlled crystallization

    Science.gov (United States)

    Zhang, Teng; Zou, Qi; Zeng, Fanrong; Wang, Shaorong; Tang, Dian; Yang, Hiswen

    2012-10-01

    The chemical compatibility of sealing glass is of great importance for Solid oxide fuel cell (SOFC). In this work, the interfacial reaction between sealing glass and Cr-containing interconnect alloy is characterized by reacting Cr2O3 powders with a representative SrO-containing glass crystallized by different heat-treatment schedules. The crystalline structure and crystalline content of sealing glass are determined by X-ray diffraction. The results show that the fraction of Cr6+ decreases from 39.8 ± 1.9% for quenched glass to 8.2 ± 0.4% for glass crystallized at 900 °C for 2 h. In addition, the interfacial reaction can be further reduced with increasing crystallization temperature and time as well as the addition of nucleation agent (TiO2). The formation of some Sr-containing crystalline phases, Sr2SiO4 and Sr(TiO3), contributes to the improvement of chemical compatibility of sealing glass, in agreement with the results of thermodynamic calculations.

  19. Use of Measured Species Class Concentrations with Chemical Kinetic Modeling for the Prediction of Autoxidation and Deposition of Jet Fuels (Postprint)

    National Research Council Canada - National Science Library

    Kuprowicz, Nicholas J; Zabarnick, Steven; West, Zachary J; Ervin, Jamie S

    2007-01-01

    .... In the present work, a chemical kinetic mechanism developed previously is refined to include the roles of key fuel species classes, such as phenols, reactive sulfur species, dissolved metals, and hydroperoxides...

  20. 3D simulation of polyurethane foam injection and reacting mold flow in a complex geometry

    Science.gov (United States)

    Özdemir, İ. Bedii; Akar, Fırat

    2018-05-01

    The aim of the present work is to develop a flow model which can be used to determine the paths of the polyurethane foam in the mold filling process of a refrigerator cabinet so that improvements in the distribution and the size of the venting holes can be achieved without the expensive prototyping and experiments. For this purpose, the multi-component, two-phase chemically reacting flow is described by Navier Stokes and 12 scalar transport equations. The air and the multi-component foam zones are separated by an interface, which moves only with advection since the mass diffusion of species are set zero in the air zone. The inverse density, viscosity and other diffusion coefficients are calculated by a mass fraction weighted average of the corresponding temperature-dependent values of all species. Simulations are performed in a real refrigerator geometry, are able to reveal the problematical zones where air bubbles and voids trapped in the solidified foam are expected to occur. Furthermore, the approach proves itself as a reliable design tool to use in deciding the locations of air vents and sizing the channel dimensions.

  1. Interspecific and Intersexual Differences in the Chemical Composition of Floral Scent in Glochidion Species (Phyllanthaceae in South China

    Directory of Open Access Journals (Sweden)

    Daihong Huang

    2015-01-01

    Full Text Available Plants of the Glochidion (Phyllanthaceae genus are pollinated exclusively by host-specific Epicephala (Gracillariidae moths. Floral scent has been thought to play key role in the obligate pollination mutualism between Glochidion plants and Epicephala moths, but few studies have been reported about chemical variation in floral volatiles of Glochidion species in China. Floral volatiles of male and female flowers of five Glochidion species in south China were collected by dynamic headspace absorption technique and then were chemically analyzed by using gas chromatography-mass spectrometry. A total of 69 compounds were identified from floral scents of five investigated species. Glochidion hirsutum and G. zeylanicum showed no qualitative differences in floral scent, whereas there were clear variations of floral scent among other species (G. eriocarpum, G. daltonii, and G. sphaerogynum and also they distinctly differed from these two species. Male flowers emitted significantly more scent than female flowers. Glochidion plants exhibited qualitative and quantitative differences in floral scent between two sexes of flowers. The findings suggest that the volatile variation of floral scent among Glochidion species reflects adaptations to specific pollinators. Sexual dimorphism in floral scent has evolved to signal alternative rewards provided by each sex to Epicephala moths.

  2. Calorific Value and Chemical Composition of Five Semi-Arid Mexican Tree Species

    Directory of Open Access Journals (Sweden)

    Maginot Ngangyo-Heya

    2016-03-01

    Full Text Available The current global energy crisis has generated growing interest in looking for alternatives to traditional fossil fuels, presenting lignocellulosic materials as a promising resource for sustainable energy production. In this paper, the calorific values and chemical composition of the trunks, branches, twigs and leaves of five timber species of the semi-arid land of Mexico (Helietta parvifolia (Gray Benth., Ebenopsis ebano (Berl. Barneby, Acacia berlandieri (Benth., Havardia pallens (Benth. Britton & Rose and Acacia wrightii (Benth. were determined according to international standards. The results highlighted the calorific value ranges of 17.56 to 18.61 MJ kg−1 in trunks, 17.15 to 18.45 MJ kg−1 in branches, 17.29 to 17.92 MJ kg−1 in twigs, and 17.35to 19.36 MJ kg−1 in leaves. The pH presented an acidic trend (3.95–5.64. The content of mineral elements varied in trunks (1.09%–2.29%, branches (0.86%–2.75%, twigs (4.26%–6.76% and leaves (5.77%–11.79%, showing the higher proportion in Ca (57.03%–95.53%, followed by K (0.95%–19.21% and Mg (0.88%–13.47%. The highest amount of extractives was obtained in the methanolic solvent (3.96%–17.03%. The lignin recorded values of 28.78%–35.84% for trunks, 17.14%–31.39% for branches and 20.61%–29.92% for twigs. Lignin showed a moderately strong correlation (r = 0.66 with calorific value, but the best mathematical model was registered with the calorific value depending on the pH and lignin (R2 = 58.86%.

  3. N2O decomposition over Fe/ZSM-5: reversible generation of highly active cationic Fe species

    NARCIS (Netherlands)

    Zhu, Q.; Hensen, E.J.M.; Mojet, B.L.; Wolput, van J.H.M.C.; Santen, van R.A.

    2002-01-01

    Fe-oxide species in Fe/ZSM-5 (prepared by chemical vapor deposition of FeCl3)-active in N2O decomposition-react with zeolite protons during high temperature calcination to give highly active cationic Fe species, this transformation being reversible upon exposure to water vapor at lower temperature

  4. Chemically reactive species in liquids generated by atmospheric-pressure plasmas and their roles in plasma medicine

    Energy Technology Data Exchange (ETDEWEB)

    Hamaguchi, Satoshi [Center for Atomic and Molecular Technologies, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871 (Japan)

    2013-07-11

    Plasmas whose gas temperatures are close to room temperature may be generated in ambient air or a gas at atmospheric pressure with the use of low-frequency high voltage or low-power radio-frequency (RF) or microwave power applied to electrodes. Such plasmas can serve as a powerful source of free radicals and/or chemically reactive species that arise from atoms and molecules of the ambient gas. Recently use of such plasmas for medical purposes has attracted much attention as they can be implemented in possible medical devices that can cause blood coagulation, heal wounds, facilitate angiogenesis, sterilize surgical devices as well as living tissues without harming healthy cells, and selectively inactivate cancer cells. Especially of interest among reactive species generated by atmospheric-pressure plasmas (APP) are reactive oxygen species (ROS) and reactive nitrogen species (RNS) that are generated in liquid phase. Since most living tissues and cells are immersed in liquids (such as blood or culture media), reactive species generated by APPs in the gas phase are transported to the liquid phase and possibly converted to different types of reactive species therein before causing some influence on the tissues or cells. In this study, the rate equations are solved to evaluate concentrations of various reactive species in pure water that are originated by plasma reactions in atmosphere and possible effects of such species (including ROS/RNS) on living tissues and cells are discussed.

  5. Chemically reactive species in liquids generated by atmospheric-pressure plasmas and their roles in plasma medicine

    International Nuclear Information System (INIS)

    Hamaguchi, Satoshi

    2013-01-01

    Plasmas whose gas temperatures are close to room temperature may be generated in ambient air or a gas at atmospheric pressure with the use of low-frequency high voltage or low-power radio-frequency (RF) or microwave power applied to electrodes. Such plasmas can serve as a powerful source of free radicals and/or chemically reactive species that arise from atoms and molecules of the ambient gas. Recently use of such plasmas for medical purposes has attracted much attention as they can be implemented in possible medical devices that can cause blood coagulation, heal wounds, facilitate angiogenesis, sterilize surgical devices as well as living tissues without harming healthy cells, and selectively inactivate cancer cells. Especially of interest among reactive species generated by atmospheric-pressure plasmas (APP) are reactive oxygen species (ROS) and reactive nitrogen species (RNS) that are generated in liquid phase. Since most living tissues and cells are immersed in liquids (such as blood or culture media), reactive species generated by APPs in the gas phase are transported to the liquid phase and possibly converted to different types of reactive species therein before causing some influence on the tissues or cells. In this study, the rate equations are solved to evaluate concentrations of various reactive species in pure water that are originated by plasma reactions in atmosphere and possible effects of such species (including ROS/RNS) on living tissues and cells are discussed

  6. Materials study for reacting plasma machine

    International Nuclear Information System (INIS)

    Kamada, Kohji; Hamada, Yasuji

    1982-01-01

    A new reacting plasma machine is designed, and will be constructed at the Institute of Plasma Physics, Nagoya University. It is important to avoid the activation of the materials for the machine, accordingly, aluminum alloy has been considered as the material since the induced activity of aluminum due to 14 MeV neutrons is small. The vacuum chamber of the new machine consists of four modules, and the remote control of each module is considered. However, the cost of the remote control of modules is expensive. To minimize the dependence on the remote control, the use of aluminum alloy is considered as the first step. The low electrical resistivity, over-ageing, weak mechanical strength and eddy current characteristics of aluminum alloy must be improved. The physical and electrical properties of various aluminum alloys have been investigated. Permeability of hydrogen through aluminum, the recycling characteristics and surface coating materials have been also studied. (Kato, T.)

  7. Quantitative imaging of turbulent and reacting flows

    Energy Technology Data Exchange (ETDEWEB)

    Paul, P.H. [Sandia National Laboratories, Livermore, CA (United States)

    1993-12-01

    Quantitative digital imaging, using planar laser light scattering techniques is being developed for the analysis of turbulent and reacting flows. Quantitative image data, implying both a direct relation to flowfield variables as well as sufficient signal and spatial dynamic range, can be readily processed to yield two-dimensional distributions of flowfield scalars and in turn two-dimensional images of gradients and turbulence scales. Much of the development of imaging techniques to date has concentrated on understanding the requisite molecular spectroscopy and collision dynamics to be able to determine how flowfield variable information is encoded into the measured signal. From this standpoint the image is seen as a collection of single point measurements. The present effort aims at realizing necessary improvements in signal and spatial dynamic range, signal-to-noise ratio and spatial resolution in the imaging system as well as developing excitation/detection strategies which provide for a quantitative measure of particular flowfield scalars. The standard camera used for the study is an intensified CCD array operated in a conventional video format. The design of the system was based on detailed modeling of signal and image transfer properties of fast UV imaging lenses, image intensifiers and CCD detector arrays. While this system is suitable for direct scalar imaging, derived quantities (e.g. temperature or velocity images) require an exceptionally wide dynamic range imaging detector. To apply these diagnostics to reacting flows also requires a very fast shuttered camera. The authors have developed and successfully tested a new type of gated low-light level detector. This system relies on fast switching of proximity focused image-diode which is direct fiber-optic coupled to a cooled CCD array. Tests on this new detector show significant improvements in detection limit, dynamic range and spatial resolution as compared to microchannel plate intensified arrays.

  8. The action of chemical and mechanical stresses on single and dual species biofilm removal of drinking water bacteria.

    Science.gov (United States)

    Gomes, I B; Lemos, M; Mathieu, L; Simões, M; Simões, L C

    2018-08-01

    The presence of biofilms in drinking water distribution systems (DWDS) is a global public health concern as they can harbor pathogenic microorganisms. Sodium hypochlorite (NaOCl) is the most commonly used disinfectant for microbial growth control in DWDS. However, its effect on biofilm removal is still unclear. This work aims to evaluate the effects of the combination of chemical (NaOCl) and mechanical stresses on the removal of single and dual species biofilms of two bacteria isolated from DWDS and considered opportunistic, Acinectobacter calcoaceticus and Stenotrophomonas maltophilia. A rotating cylinder reactor was successfully used for the first time in drinking water biofilm studies with polyvinyl chloride as substratum. The single and dual species biofilms presented different characteristics in terms of metabolic activity, mass, density, thickness and content of proteins and polysaccharides. Their complete removal was not achieved even when a high NaOCl concentrations and an increasing series of shear stresses (from 2 to 23Pa) were applied. In general, NaOCl pre-treatment did not improve the impact of mechanical stress on biofilm removal. Dual species biofilms were colonized mostly by S. maltophilia and were more susceptible to chemical and mechanical stresses than these single species. The most efficient treatment (93% biofilm removal) was the combination of NaOCl at 175mg·l -1 with mechanical stress against dual species biofilms. Of concern was the high tolerance of S. maltophilia to chemical and mechanical stresses in both single and dual species biofilms. The overall results demonstrate the inefficacy of NaOCl on biofilm removal even when combined with high shear stresses. Copyright © 2018 Elsevier B.V. All rights reserved.

  9. Comparison of two freshwater turtle species as monitors of radionuclide and chemical contamination: DNA damage and residue analysis

    International Nuclear Information System (INIS)

    Meyers-Schoene, L.; Shugart, L.R.; Beauchamp, J.J.; Walton, B.T.

    1993-01-01

    Two species of turtles that occupy different ecological niches were compared for their usefulness as monitors of freshwater ecosystems where both low-level radioactive and nonradioactive contaminants are present. The pond slider (Trachemys scripta) and common snapping turtle (Chelydra serpentina) were analyzed for the presence of 90 Sr, 137 Cs, 60 Co, and Hg, radionuclides and chemicals known to be present at the contaminated site, and single-strand breaks in liver DNA. The integrity of the DNA was examined by the alkaline unwinding assay, a technique that detects strand breaks as a biological marker of possible exposure to genotoxic agents. This measure of DNA damage was significantly increased in both species of turtles at the contaminated site compared with turtles of the same species at a reference site, and shows that contaminant-exposed populations were under more severe genotoxic stress than those at the reference site. The level of strand breaks observed at the contaminated site was high and in the range reported for other aquatic species exposed to deleterious concentrations of genotoxic agents such as chemicals and ionizing radiation. Statistically significantly higher concentrations of radionuclides and Hg were detected in the turtles from the contaminated area. Mercury concentrations were significantly higher in the more carnivorous snapping turtle compared with the slider; however, both species were effective monitors of the contaminants

  10. The physico-chemical 131I species in the exhaust air of a boiling water reactor (BWR 4)

    International Nuclear Information System (INIS)

    Deuber, H.

    1982-12-01

    In a German boiling water reactor, the physico-chemical 131 I species were determined in the plant exhaust and in the individual exhausts during 12 months. These measurements aimed in particular at determining the percentage and the source of the radiologically decisive elemental 131 I released to the environment. The retention of the 131 I species by iodine filters was also investigated. On an average, 45% of the 131 I discharged with the plant exhaust consisted of elemental iodine. This was largely released with the exhaust from the reactor building and from the turbine building. The other 55% consisted almost entirely of organic I. (orig./HP) [de

  11. The major differences in chemical composition and antibacterial activity of two closely related Leonotis species (Lamiaceae may have taxonomic value

    Directory of Open Access Journals (Sweden)

    J.N. Eloff

    2010-01-01

    Full Text Available Several Leonotis species are used widely for medicinal purposes in Africa. There have been drastic changes in the taxonomic treatment of Leonotis species during the past decade. Two species, L. dysophylla and L. microphylla occurring in Pretoria have been considered as varieties of the same species and as different species by different authors. Because Leonotis species are used widely as medicinal plants inter alia against bacterial infections, we decided to compare the chemical composition and antibacterial activity of four plants from each of two populations of the species. The chemical composition of acetone extracts of finely ground leaves was determined by thin layer chromatography followed by spraying with vanillin-sulphuric acid. There were hardly any differences between plants from the same population. There were major differences between the two species in the composition of pigments separated by thin layer chromatography and for compounds visualized with the vanillin-sulphuric acid spray reagent. This supported the viewpoint that the two species should not be considered as varieties. The major differences found in chemical composition indicate that chemical parameters may play an important role in resolving taxonomic differences. Because such a small quantity of material is needed, it may be feasible to analyze one or two leaves obtained from herbarium sheets as an additional taxonomic parameter. The antibacterial activity of the acetone extracts was determined using a two-fold serial dilution microplate method with tetrazolium violet as indicator of growth. The specific strains of the four most important nosocomial bacterial pathogens suggested by the United States National Committee for Clinical Laboratory Standards were used: Staphylococcus aureus (American Type Culture Collection 29213, Pseudomonas aeruginosa (ATCC 27853, Escherichia coli (ATCC 25922 and Enterococcus faecalis (ATCC 21212. The minimum inhibitory activity of the

  12. Organic Redox Species in Aqueous Flow Batteries: Redox Potentials, Chemical Stability and Solubility

    OpenAIRE

    Kristina Wedege; Emil Dražević; Denes Konya; Anders Bentien

    2016-01-01

    Organic molecules are currently investigated as redox species for aqueous low-cost redox flow batteries (RFBs). The envisioned features of using organic redox species are low cost and increased flexibility with respect to tailoring redox potential and solubility from molecular engineering of side groups on the organic redox-active species. In this paper 33, mainly quinone-based, compounds are studied experimentially in terms of pH dependent redox potential, solubility and stability, combined ...

  13. The influence of stream bed geomorphology on chemical species within the hyporheic zone over time and space

    Science.gov (United States)

    Quick, A. M.; Reeder, W. J.; Farrell, T. B.; Benner, S. G.; Tonina, D.; Feris, K. P.

    2017-12-01

    The hyporheic zone is well established as an important zone of biogeochemical activity in streams and rivers. Multiple large scale flume experiments were carried out to mimic bedform-controlled hyporheic zones in small streams. The laboratory setting allowed for geochemical measurement resolution and replicates that would not be possible in a natural setting. Two flume experiments that consisted of three small streams with variable sizes of bedform dunes were carried out in which chemical species were measured in the surface water and along hyporheic flow lines in the subsurface. The species measured included dissolved oxygen, pH, alkalinity, major cations (Na+, Mg2+, Ca2+, K+, Si4+, Al3+), anions (NO3-, NO2-, SO42-, PO43-, Cl-), and many trace elements (As, Sr, Co, Ni, Cu, Zn, Pb, U, V). Observed spatial and temporal trends reflect microbiological processes, changing redox conditions, and chemical weathering. In general, microbial respiration causes DO to decrease with residence time, leading to aerobic and anaerobic zones that influence redox-sensitive species and pH gradients that influence mineral solubility. Most other species concentrations, including those of major cations and trace elements, increase with residence time and generally decrease over time elapsed during the experiment. The different dune morphologies dictate flow velocities in the hyporheic zone; for most species, steeper dunes with higher velocities had lower concentrations at the end of the experiment, indicating the role of dune shape in the weathering rates of minerals in hyporheic sediment and the concentrations of dissolved species entering the surface water over time. Many of the observed trends can be applied, at least qualitatively, to understanding how these species will behave in natural settings. This insight will contribute to the understanding of many of the applications of the hyporheic zone (e.g. bioremediation, habitat, greenhouse gas emissions, etc.).

  14. Komponen Kimia Minyak Atsiridaun Tiga Jenis Piperaceae*[chemical Compounds of Essential Oil on Three Piperaceae Species

    OpenAIRE

    Jamal, Yuliasri

    2002-01-01

    Chemical analysis of leaves essential oil on three Piper species, P. malamiri, P. baccatum and P. majusculum was conducted using gas chromatography and mass spectrometry (GCMS) method.Chromatogram result showed 52, 56 and 47 peaks on leaves essential oil of P.malamiri, P.baccatum and P.majusculum respectively. Based on the peaks,it is known that isocaryofilene is the major, common and as the highest component found in the three essential oils, beside several other major components.

  15. On the segregation of chemical species in a clear boundary layer over heterogeneous land surfaces

    NARCIS (Netherlands)

    Ouwersloot, H.G.; Vilà-Guerau de Arellano, J.; Heerwaarden, van C.C.; Ganzeveld, L.N.; Krol, M.C.; Lelieveld, J.

    2011-01-01

    Using a Large-Eddy Simulation model, we have systematically studied the inability of boundary layer turbulence to efficiently mix reactive species. This creates regions where the species are accumulated in a correlated or anti-correlated way, thereby modifying the mean reactivity. We quantify this

  16. Unravelling chemical priming machinery in plants: the role of reactive oxygen-nitrogen-sulfur species in abiotic stress tolerance enhancement.

    Science.gov (United States)

    Antoniou, Chrystalla; Savvides, Andreas; Christou, Anastasis; Fotopoulos, Vasileios

    2016-10-01

    Abiotic stresses severely limit crop yield and their detrimental effects are aggravated by climate change. Chemical priming is an emerging field in crop stress management. The exogenous application of specific chemical agents before stress events results in tolerance enhancement and reduction of stress impacts on plant physiology and growth. However, the molecular mechanisms underlying the remarkable effects of chemical priming on plant physiology remain to be elucidated. Reactive oxygen, nitrogen and sulfur species (RONSS) are molecules playing a vital role in the stress acclimation of plants. When applied as priming agents, RONSS improve stress tolerance. This review summarizes the recent knowledge on the role of RONSS in cell signalling and gene regulation contributing to abiotic stress tolerance enhancement. Copyright © 2016 Elsevier Ltd. All rights reserved.

  17. Species diversity and chemical properties of litter influence non-additive effects of litter mixtures on soil carbon and nitrogen cycling.

    Directory of Open Access Journals (Sweden)

    Bing Mao

    Full Text Available Decomposition of litter mixtures generally cannot be predicted from the component species incubated in isolation. Therefore, such non-additive effects of litter mixing on soil C and N dynamics remain poorly understood in terrestrial ecosystems. In this study, litters of Mongolian pine and three dominant understory species and soil were collected from a Mongolian pine plantation in Northeast China. In order to examine the effects of mixed-species litter on soil microbial biomass N, soil net N mineralization and soil respiration, four single litter species and their mixtures consisting of all possible 2-, 3- and 4-species combinations were added to soils, respectively. In most instances, species mixing produced synergistic non-additive effects on soil microbial biomass N and soil respiration, but antagonistic non-additive effects on net N mineralization. Species composition rather than species richness explained the non-additive effects of species mixing on soil microbial biomass N and net N mineralization, due to the interspecific differences in litter chemical composition. Both litter species composition and richness explained non-additive soil respiration responses to mixed-species litter, while litter chemical diversity and chemical composition did not. Our study indicated that litter mixtures promoted soil microbial biomass N and soil respiration, and inhibited net N mineralization. Soil N related processes rather than soil respiration were partly explained by litter chemical composition and chemical diversity, highlighting the importance of functional diversity of litter on soil N cycling.

  18. Species diversity and chemical properties of litter influence non-additive effects of litter mixtures on soil carbon and nitrogen cycling.

    Science.gov (United States)

    Mao, Bing; Mao, Rong; Zeng, De-Hui

    2017-01-01

    Decomposition of litter mixtures generally cannot be predicted from the component species incubated in isolation. Therefore, such non-additive effects of litter mixing on soil C and N dynamics remain poorly understood in terrestrial ecosystems. In this study, litters of Mongolian pine and three dominant understory species and soil were collected from a Mongolian pine plantation in Northeast China. In order to examine the effects of mixed-species litter on soil microbial biomass N, soil net N mineralization and soil respiration, four single litter species and their mixtures consisting of all possible 2-, 3- and 4-species combinations were added to soils, respectively. In most instances, species mixing produced synergistic non-additive effects on soil microbial biomass N and soil respiration, but antagonistic non-additive effects on net N mineralization. Species composition rather than species richness explained the non-additive effects of species mixing on soil microbial biomass N and net N mineralization, due to the interspecific differences in litter chemical composition. Both litter species composition and richness explained non-additive soil respiration responses to mixed-species litter, while litter chemical diversity and chemical composition did not. Our study indicated that litter mixtures promoted soil microbial biomass N and soil respiration, and inhibited net N mineralization. Soil N related processes rather than soil respiration were partly explained by litter chemical composition and chemical diversity, highlighting the importance of functional diversity of litter on soil N cycling.

  19. Analysis of Environmental Physical-Chemical Factors and Macroalga Species In The Coastal Water of Nusalaut, Central Maluku - Indonesia

    Directory of Open Access Journals (Sweden)

    Karel Melsasail

    2018-03-01

    Full Text Available The physical-chemical factors of environment are very influential on the presence and the growth of macrolaga in waters. Well-maintained water habitat is a good environment for the growth of macroalgae. A research has been conducted on the physicochemical environmental factors and the macroalgae species in the coastal waters of Nusalaut Island using transect method, and it was a survey research on four different observation stations. The results of the research showed that station I (Amet Village has the best physicochemical factors for the presence and the growth of macroalgae, compared to station II (Nalahia Village, station III (Sila Village and station IV (Leinitu Village. The most widely found macro algae are from the Rhodophyta class, with a total of 17 species of macroalgae, of which 15 species are found in station I.

  20. Consideration on thermodynamic data for predicting solubility and chemical species of elements in groundwater. Part 2: Np, Pu

    International Nuclear Information System (INIS)

    Yamaguchi, Tetsuji

    2000-11-01

    The solubility determines the release of a radionuclide from waste form and is used as a source term in radionuclide migration analysis in performance assessment of radioactive waste repository. Complexations of the radionuclide by ligands in groundwater affect the interaction between radionuclides and geologic media, thus affect their migration behavior. It is essential to estimate the solubility and to predict the chemical species for the radionuclide based on thermodynamic data. The thermodynamic data of aqueous species and compounds were reviewed and compiled for Np and Pu. Thermodynamic data were reviewed with emphasis on the hydrolysis and carbonate complexation that can dominate the speciation in groundwater. Thermodynamic data for other species were selected based on existing databases. Thermodynamic data for other important elements are under investigation, thus shown in an appendix for temporary use. (author)

  1. Chemical analogy in the case of hydrolysis species of F-elements

    International Nuclear Information System (INIS)

    Hirotake Moriyama; Hajimu Yamana; Kenso Fujiwara

    2001-01-01

    In spite of much importance, some of the thermodynamic data of actinide elements are still lacking, and the chemical behaviour of these elements is often predicted by considering chemical analogy, that is by taking the known data of the same and similar group elements. It is thus quite important to establish the basis and conditions for applying the chemical analogy. In the present study, some topics are discussed which are related with the chemical analogy for the hydrolysis behaviour of actinide ions. Systematic trends of the thermodynamic data of actinide ions, namely the solubility products and hydrolysis constants, are discussed by considering the results of recent measurements and by considering possible contributions of non-electrostatic interactions of actinide ions in addition to those of ordinary electrostatic ones. (authors)

  2. ANATOMICAL CHARACTERISTICS AND CHEMICAL PROPERTIES OF THE BRANCH-WOOD OF Schizolobium amazonicum DUCKE SPECIES AND ITS POTENTIAL USES

    Directory of Open Access Journals (Sweden)

    Yusup Amin

    2013-10-01

    Full Text Available The scale of forest degradation and deforestation in Indonesia has inspired the use of lesser-known wood species, which are potentially abundant and so far has not much been utilized. Utilization of these woods should be imposed not only of the stem wood but also of the branch-wood portions. Schizolobiumamazonicum Ducke treeis one of those lesser-known species, and growing fast with an MAIof3.68 cm/year.In Indonesia this species is only found in the Purwodadi Botanical Garden. A research was conducted to study the basic characteristics (anatomical aspects and chemical properties of the branch-wood portion of this species. The branch-wood materials were obtained from the Purwodadi Botanical Garden situated in Pasuruan (East Java. The specimens used were the first branch of the trunk (stem of nine-year old S. amazonicum tree (= 29.46 cm. The branch-wood samples were then examined for the anatomical aspects (macroscopic and microscopic characteristics and chemical properties (chemical composition. Results revealed that the anatomical properties of S.amazonicum branch-wood exhibited close similarities to those of sengon wood; it was light in appearance and white in color. Its fiber averaged about 1500 μm, and based on the fiber dimension's derived values the branch- wood fiber of this species was categorized into first-class quality for pulp and paper manufacture. Further, the chemical composition of this branch-wood compared favorably with that of sengon and mangium wood. The composition of extractive content thatsoluble in alcohol-benzene; lignin; holocellulose; and α-cellulose of this branch-wood were 2.46; 28.71; 80.64; and 50.47%, respectively. The overall assessment implied that the branch-wood portion of S.amazonicum tree affords favorable potential to be developed as raw material for pulp and paper manufacture. Also, considering that both sengon and mangium woods were already used in the pulp and paper industries as well as the trees are

  3. Demonstration of Hybrid DSMC-CFD Capability for Nonequilibrium Reacting Flow

    Science.gov (United States)

    2018-02-09

    AFRL-RV-PS- TR-2018-0056 AFRL-RV-PS- TR-2018-0056 DEMONSTRATION OF HYBRID DSMC-CFD CAPABILITY FOR NONEQUILIBRIUM REACTING FLOW Thomas E...4. TITLE AND SUBTITLE Demonstration of Hybrid DSMC-CFD Capability for Nonequilibrium Reacting Flow 5a. CONTRACT NUMBER 5b. GRANT NUMBER FA9453-17-1...simulation codes. The models are based on new ab-intio rate data obtained using state -of-the-art potential energy surfaces for air species. A probability

  4. MPSalsa a finite element computer program for reacting flow problems. Part 2 - user`s guide

    Energy Technology Data Exchange (ETDEWEB)

    Salinger, A.; Devine, K.; Hennigan, G.; Moffat, H. [and others

    1996-09-01

    This manual describes the use of MPSalsa, an unstructured finite element (FE) code for solving chemically reacting flow problems on massively parallel computers. MPSalsa has been written to enable the rigorous modeling of the complex geometry and physics found in engineering systems that exhibit coupled fluid flow, heat transfer, mass transfer, and detailed reactions. In addition, considerable effort has been made to ensure that the code makes efficient use of the computational resources of massively parallel (MP), distributed memory architectures in a way that is nearly transparent to the user. The result is the ability to simultaneously model both three-dimensional geometries and flow as well as detailed reaction chemistry in a timely manner on MT computers, an ability we believe to be unique. MPSalsa has been designed to allow the experienced researcher considerable flexibility in modeling a system. Any combination of the momentum equations, energy balance, and an arbitrary number of species mass balances can be solved. The physical and transport properties can be specified as constants, as functions, or taken from the Chemkin library and associated database. Any of the standard set of boundary conditions and source terms can be adapted by writing user functions, for which templates and examples exist.

  5. Direct numerical simulations of reacting flows with detailed chemistry using many-core/GPU acceleration

    KAUST Repository

    Herná ndez Pé rez, Francisco E.; Mukhadiyev, Nurzhan; Xu, Xiao; Sow, Aliou; Lee, Bok Jik; Sankaran, Ramanan; Im, Hong G.

    2018-01-01

    A new direct numerical simulation (DNS) code for multi-component gaseous reacting flows has been developed at KAUST, with the state-of-the-art programming model for next generation high performance computing platforms. The code, named KAUST Adaptive Reacting Flows Solver (KARFS), employs the MPI+X programming, and relies on Kokkos for “X” for performance portability to multi-core, many-core and GPUs, providing innovative software development while maintaining backward compatibility with established parallel models and legacy code. The capability and potential of KARFS to perform DNS of reacting flows with large, detailed reaction mechanisms is demonstrated with various model problems involving ignition and turbulent flame propagations with varying degrees of chemical complexities.

  6. Direct numerical simulations of reacting flows with detailed chemistry using many-core/GPU acceleration

    KAUST Repository

    Hernández Pérez, Francisco E.

    2018-03-29

    A new direct numerical simulation (DNS) code for multi-component gaseous reacting flows has been developed at KAUST, with the state-of-the-art programming model for next generation high performance computing platforms. The code, named KAUST Adaptive Reacting Flows Solver (KARFS), employs the MPI+X programming, and relies on Kokkos for “X” for performance portability to multi-core, many-core and GPUs, providing innovative software development while maintaining backward compatibility with established parallel models and legacy code. The capability and potential of KARFS to perform DNS of reacting flows with large, detailed reaction mechanisms is demonstrated with various model problems involving ignition and turbulent flame propagations with varying degrees of chemical complexities.

  7. Toxicity of fire retardant chemicals and fire suppressant foams to vertebrate and invertebrate wildlife species

    Science.gov (United States)

    Vyas, Nimish B.; Hill, Elwood F.

    1996-01-01

    Under laboratory conditions, acute single-dose oral toxicity tests (LD50) were conducted with three fire retardant chemicals (Fire-Trol GTS-R, Phos-Chek D75-F, and Fire-Trol LCG-R) and two fire suppressant foams (Silv-Ex and Phos-Chek WD-881) to determine effects on adult northern bobwhite, American kestrel, red-winged blackbird, and white-footed mouse. In addition, earthworms were exposed (LC50) for 14 days in treated soil.In general, no toxic responses were evident. For northern bobwhite, the LD50 for all five chemicals was >2000 mg a.l./kg of body mass. American kestrels regurgitated all chemicals except Silv-ex; LD50s all exceeded 2000 mg/kg. The LD50 for red-winged blackbird was also >2000 mg/kg for all chemicals except Fire-Trol GTS-R which is currently undergoing further testing. In addition, the LD50 for white-footed mouse was >2000 mg/kg for Phos-Chek D75F. The 14-day LC50 for earthworms was >1000 ppm for all chemicals. Therefore, we concluded that these retardants and foams do not pose an acute hazard to adult birds, mammals, or earthworms. However, ecological studies to evaluate the potential effects of these formulations on vertebrate behavior and population dynamics are in progress.

  8. Spatial distribution and temporal variation of chemical species in the bulk atmospheric aerosols collected at the Okinawa archipelago, Japan

    Science.gov (United States)

    Handa, D.; Somada, Y.; Ijyu, M.; Azechi, S.; Nakaema, F.; Arakaki, T.; Tanahara, A.

    2009-12-01

    The economic development and population growth in recent Asia have been increasing air pollution. A computer simulation study showed that air pollutants emitted from Asian continent could spread quickly within northern hemisphere. We initiated a study to elucidate the special distribution and chemical characterization of atmospheric aerosols around Okinawa archipelago, Japan. Okinawa Island is situated approximately 1500 km south of Tokyo, Japan, 2000 km southeast of Beijing, China, and 1000 km south of South Korea. Its location in Asia is well suited for studying long-range transport of air pollutants in East Asia because maritime air mass prevails during summer, while continental air mass dominates during fall, winter, and spring. The maritime air mass data can be seen as background and can be compared with continental air masses which have been affected by anthropogenic activities. We simultaneously collected bulk aerosol samples by using the same types of high volume air samplers at Cape Hedo Atmosphere and Aerosol Monitoring Station (CHAAMS, Okinawa Island), Kume Island (ca. 160 km south-west of CHAAMS) and Minami-daitou Island (ca. 320 km south-east of CHAAMS). We determined the concentrations of water-soluble anions, cations and dissolved organic carbon (DOC) using ion chromatography, atomic absorption spectrometry, and total organic carbon analyzer, respectively. We report and discuss spatial distribution and temporal variation of chemical species concentrations in bulk atmospheric aerosols collected during July, 2008 to July, 2009. We determine “background” concentration of chemical components in Okinawa archipelago. We then compare each chemical component among CHAAMS, Kume Island and Minami-daito Island to elucidate the influence of the long-range transport of chemical species from Asian continent.

  9. Volatile constituents from Baccharis spp. L. (Asteraceae): Chemical support for the conservation of threatened species in Uruguay.

    Science.gov (United States)

    Minteguiaga, Manuel; Andrés González, H; Cassel, Eduardo; Umpierrez, Noelia; Fariña, Laura; Dellacassa, Eduardo

    2018-03-14

    Chemical bioprospecting is an important tool for generating knowledge regarding local human-threatened floras and for conservation management. For Baccharis L. (Asteraceae), several volatile components have been reported for Brazil, Argentina, Bolivia, and Chile as a result of bioprospection, but not for Uruguayan flora, which is composed of more than 50 native species. In this work, through collection of aerial parts of different species and volatile simultaneous-distillation extraction and gas chromatography-mass spectrometry analyses, 12 native species of Baccharis were studied (B. articulata, B. cultrata, B. genistifolia, B. gibertii, B. gnaphalioides, B. ochracea, B. phyteumoides, B. punctulata, B. crispa, B. dracunculifolia, B. linearifolia subsp. linearifolia, and B. spicata). A detailed analysis of the male and female volatile composition was conducted for the last four species. The profiles of B. cultrata, B. genistifolia, B. gibertii, and B. gnaphalioides are reported for the first time. Because half of the species analysed in this work are in Uruguay and are threatened or potentially threatened by human economic activities, the importance of their conservation as natural, sustainable resources is highlighted. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  10. Antimatter persuaded to react with matter

    CERN Multimedia

    Van Noorden, Richard

    2006-01-01

    "Matter and antimatter usually destroy each other in a flash of energy and a spray of exotic particles when they meet. Yet the two have been coaxed into a chemical reaction by the international research group Athena." (2/3 page)

  11. Studies on the origin and transformation of selenium and its chemical species along the process of petroleum refining

    Science.gov (United States)

    Stivanin de Almeida, Cibele M.; Ribeiro, Anderson S.; Saint'Pierre, Tatiana D.; Miekeley, Norbert

    2009-06-01

    Inductively coupled plasma optical emission spectrometry and mass spectrometry (ICPMS), the latter hyphenated to flow injection hydride generation, electrothermal vaporization or ion chromatography, have been applied to the chemical characterization of crude oil, aqueous process stream samples and wastewaters from a petroleum refinery, in order to get information on the behavior of selenium and its chemical species along effluent generation and treatment. Multielemental characterization of these effluents by ICPMS revealed a complex composition of most of them, with high salinity and potential spectral and non-spectral interferents present. For this reason, a critical re-assessment of the analytical techniques for the determination of total selenium and its species was performed. Methane was employed as gas in dynamic reaction cell ICPMS and cell parameters were optimized for a simulated brine matrix and for diluted aqueous solutions to match the expected process and treated wastewaters samples. The signal-to-background ratios for 78Se and 80Se were used as criteria in optimization, the first isotope resulting in better detection limits for the simulated brine matrix ( 78Se: 0.07 μg L - 1 , 80Se: 0.31 μg L - 1 ). A large variability in the concentration of selenium (from crude oil samples in the refinery here investigated, which may explain the pronounced concentrations changes of this element measured in aqueous process stream and wastewater samples. Highest concentrations of total selenium were analyzed in samples from the hydrotreater (up to about 1800 μg L - 1 ). The predominance of selenocyanate (SeCN -) was observed in most of the wastewaters so far investigated, but also other species were detected with retention times different from Se(IV), Se(VI) and SeCN -. Colloidal selenium (Se 0) was the only Se-species observed in samples from the atmospheric distillation unit, but was also identified in other samples, most probably formed by the decomposition of

  12. A High Throughput Ambient Mass Spectrometric Approach to Species Identification and Classification from Chemical Fingerprint Signatures

    Science.gov (United States)

    Musah, Rabi A.; Espinoza, Edgard O.; Cody, Robert B.; Lesiak, Ashton D.; Christensen, Earl D.; Moore, Hannah E.; Maleknia, Simin; Drijfhout, Falko P.

    2015-01-01

    A high throughput method for species identification and classification through chemometric processing of direct analysis in real time (DART) mass spectrometry-derived fingerprint signatures has been developed. The method entails introduction of samples to the open air space between the DART ion source and the mass spectrometer inlet, with the entire observed mass spectral fingerprint subjected to unsupervised hierarchical clustering processing. A range of both polar and non-polar chemotypes are instantaneously detected. The result is identification and species level classification based on the entire DART-MS spectrum. Here, we illustrate how the method can be used to: (1) distinguish between endangered woods regulated by the Convention for the International Trade of Endangered Flora and Fauna (CITES) treaty; (2) assess the origin and by extension the properties of biodiesel feedstocks; (3) determine insect species from analysis of puparial casings; (4) distinguish between psychoactive plants products; and (5) differentiate between Eucalyptus species. An advantage of the hierarchical clustering approach to processing of the DART-MS derived fingerprint is that it shows both similarities and differences between species based on their chemotypes. Furthermore, full knowledge of the identities of the constituents contained within the small molecule profile of analyzed samples is not required. PMID:26156000

  13. Chemical composition of hydroethanolic extracts from five species of the Passiflora genus

    Directory of Open Access Journals (Sweden)

    Marna E Sakalem

    2012-09-01

    Full Text Available The diversified genus Passiflora is well distributed all over Brazil, and many species have been long used as medicinal plants, mainly against anxiety disturbances. This effect has been attributed to its rich flavonoid composition. Flavonoids’ main class, flavonoid glycosides, has presented central action, particularly as sedative-hypnotic, anxiolytic and analgesic. The objective of the present study was to make a phytochemical screening of five little studied Passiflora species, in order to evaluate their phenolic composition. For this aim, HPLC-DAD-ESI-MS/MS was used. After the preparation of the hydroalcoholic extracts, each species was evaluated by direct injection electrospray ionization (ESI and tandem mass spectrometry. Although belonging to the same genus, the composition of each species presented particularities; this justifies the importance of studies aiming for the phenolic composition of different Passiflora species. Flavones C-glycosides were detected in all extracts, and are found as the main constituents in P. vitifolia, P. coccinea, P. bahiensis and P. sidifolia. In this last one, flavone-6,8-di-C-glycoside, apigenin-6-C-rhamnosyl-8-C-arabinoside are present in high content. Cyclopassiflosides were found in high content together with cyanogenic glycosides in P. quadrangularis, while in P. coccinea, besides flavones-C-glycosides were also found procyanidins.

  14. Chemical composition of hydroethanolic extracts from five species of the Passiflora genus

    Directory of Open Access Journals (Sweden)

    Marna E Sakalem

    2012-12-01

    Full Text Available The diversified genus Passiflora is well distributed all over Brazil, and many species have been long used as medicinal plants, mainly against anxiety disturbances. This effect has been attributed to its rich flavonoid composition. Flavonoids’ main class, flavonoid glycosides, has presented central action, particularly as sedative-hypnotic, anxiolytic and analgesic. The objective of the present study was to make a phytochemical screening of five little studied Passiflora species, in order to evaluate their phenolic composition. For this aim, HPLC-DAD-ESI-MS/MS was used. After the preparation of the hydroalcoholic extracts, each species was evaluated by direct injection electrospray ionization (ESI and tandem mass spectrometry. Although belonging to the same genus, the composition of each species presented particularities; this justifies the importance of studies aiming for the phenolic composition of different Passiflora species. Flavones C-glycosides were detected in all extracts, and are found as the main constituents in P. vitifolia, P. coccinea, P. bahiensis and P. sidifolia. In this last one, flavone-6,8-di-C-glycoside, apigenin-6-C-rhamnosyl-8-C-arabinoside are present in high content. Cyclopassiflosides were found in high content together with cyanogenic glycosides in P. quadrangularis, while in P. coccinea, besides flavones-C-glycosides were also found procyanidins.

  15. Phytotoxic effects and chemical analysis of leaf extracts from three Phytolaccaceae species in South Korea.

    Science.gov (United States)

    Kim, Yong Ok; Johnson, Jon D; Lee, Eun Ju

    2005-05-01

    We analyzed phenolic compounds and other elements in leaf extracts and compared morphology of three species of the Phytolaccaceae family found in South Korea. To test allelochemical effects of the three Phytolacca species, we also examined seed germination and dry weight of seedlings of Lactuca indica and Sonchus oleraceus treated with leaf extracts. The concentrations of total phenolic compounds were exotic Phytolacca esculenta (3.9 mg/l), native Phytolacca insularis (4.4 mg/l), and exotic Phytolacca americana (10.2 mg/l). There was no significant difference in concentrations between P. esculenta and P. insularis, but the concentration of total phenolics in P. americana was two times higher than either P. esculenta or P. insularis. Analysis of aqueous extracts by HPLC showed seven phenolic compounds (gallic acid, protocatechuic acid, chlorogenic acid, caffeic acid, m-hydroxybenzoic acid, p-coumaric acid, and cinnamic acid). Total phenolics in P. americana were eight to 16 times higher than either P. esculenta or P. insularis, respectively. P. americana inhibited seed germination and dry weight of the two assay species. The phytotoxic effects of the two Phytolacca species were different, despite the fact that P. esculenta and P. insularis had similar levels of total phenolic compounds. We also found that P. americana had invaded Ullung Island, which suggested that P. americana had excellent adaptability to the environment. The three species of Phytolaccaceae in South Korea can be distinguished by their different allelopathic potentials and morphologies.

  16. Effects of Pig Slurry Application and Crops on Phosphorus Content in Soil and the Chemical Species in Solution

    Directory of Open Access Journals (Sweden)

    Lessandro De Conti

    2015-06-01

    Full Text Available The application of pig slurry rates and plant cultivation can modify the soil phosphorus (P content and distribution of chemical species in solution. The purpose of this study was to evaluate the total P, available P and P in solution, and the distribution of chemical P species in solution, in a soil under longstanding pig slurry applications and crop cultivation. The study was carried out in soil columns with undisturbed structure, collected in an experiment conducted for eight years in the experimental unit of the Universidade Federal de Santa Maria (UFSM, Santa Maria (RS. The soil was an Argissolo Vermelho distrófico arênico (Typic Hapludalf, subjected to applications of 0, 20, 40, and 80 m3 ha-1 pig slurry. Soil samples were collected from the layers 0-5, 5-10, 10-20, 20-30, 30-40, and 40-60 cm, before and after black oat and maize grown in a greenhouse, for the determination of available P, total P and P in the soil solution. In the solution, the concentration of the major cations, anions, dissolved organic carbon (DOC, and pH were determined. The distribution of chemical P species was determined by software Visual Minteq. The 21 pig slurry applications increased the total P content in the soil to a depth of 40 cm, and the P extracted by Mehlich-1 and from the solution to a depth of 30 cm. Successive applications of pig slurry changed the balance between the solid and liquid phases in the surface soil layers, increasing the proportion of the total amount of P present in the soil solution, aside from changing the chemical species in the solution, reducing the percentage complexed with Al and increasing the one complexed with Ca and Mg in the layers 0-5 and 5-10 cm. Black oat and maize cultivation increased pH in the solution, thereby increasing the proportion of HPO42- and reducing H2PO4- species.

  17. Chemical composition of the essential oil and hexanic fraction of Lippia and Lantana species

    Directory of Open Access Journals (Sweden)

    Pâmela S. Silva

    2010-11-01

    Full Text Available A comparison between two extraction approaches of volatiles compounds from six species of Verbenaceae collected at Serra do Cipó, Minas Gerais, Brazil was done. The essential oil and hexanic fraction of leaves from two Lantana and four Lippia species collected in two different seasons were analyzed by GC/MS. Among various identified compounds from both extraction methods the majority of species showed major amounts of β-caryophyllene followed by germacrene D, bicyclogermacrene and α-pinene. Few differences were observed between the composition of essential oil and the hexanic fraction regarding the two studied genera. These results suggest that the analysis of hexanic fraction can be used, as an alternative way, to analyze the volatile compounds of the essential oil.

  18. Chemical Composition and Seasonality of Aromatic Mediterranean Plant Species by NMR-Based Metabolomics

    Directory of Open Access Journals (Sweden)

    Monica Scognamiglio

    2015-01-01

    Full Text Available An NMR-based metabolomic approach has been applied to analyse seven aromatic Mediterranean plant species used in traditional cuisine. Based on the ethnobotanical use of these plants, the approach has been employed in order to study the metabolic changes during different seasons. Primary and secondary metabolites have been detected and quantified. Flavonoids (apigenin, quercetin, and kaempferol derivatives and phenylpropanoid derivatives (e.g., chlorogenic and rosmarinic acid are the main identified polyphenols. The richness in these metabolites could explain the biological properties ascribed to these plant species.

  19. Chemical Composition and Seasonality of Aromatic Mediterranean Plant Species by NMR-Based Metabolomics.

    Science.gov (United States)

    Scognamiglio, Monica; D'Abrosca, Brigida; Esposito, Assunta; Fiorentino, Antonio

    2015-01-01

    An NMR-based metabolomic approach has been applied to analyse seven aromatic Mediterranean plant species used in traditional cuisine. Based on the ethnobotanical use of these plants, the approach has been employed in order to study the metabolic changes during different seasons. Primary and secondary metabolites have been detected and quantified. Flavonoids (apigenin, quercetin, and kaempferol derivatives) and phenylpropanoid derivatives (e.g., chlorogenic and rosmarinic acid) are the main identified polyphenols. The richness in these metabolites could explain the biological properties ascribed to these plant species.

  20. Evaluation of thermal, chemical, and mechanical seed scarification methods for 4 Great Basin lupine species

    Science.gov (United States)

    Covy D. Jones; Mikel R. Stevens; Von D. Jolley; Bryan G. Hopkins; Scott L. Jensen; Dave Turner; Jason M. Stettler

    2016-01-01

    Seeds of most Great Basin lupine (Lupinus spp. [Fabaceae]) species are physically dormant and thus, difficult to establish in uniform stands in seed production fields. We designed this study to examine 5 seed scarification techniques, each with 11 levels of application (including a non-scarified control), to reduce the physical seed dormancy of longspur lupine...

  1. Nonlinear Krylov acceleration of reacting flow codes

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, S.; Rawat, R.; Smith, P.; Pernice, M. [Univ. of Utah, Salt Lake City, UT (United States)

    1996-12-31

    We are working on computational simulations of three-dimensional reactive flows in applications encompassing a broad range of chemical engineering problems. Examples of such processes are coal (pulverized and fluidized bed) and gas combustion, petroleum processing (cracking), and metallurgical operations such as smelting. These simulations involve an interplay of various physical and chemical factors such as fluid dynamics with turbulence, convective and radiative heat transfer, multiphase effects such as fluid-particle and particle-particle interactions, and chemical reaction. The governing equations resulting from modeling these processes are highly nonlinear and strongly coupled, thereby rendering their solution by traditional iterative methods (such as nonlinear line Gauss-Seidel methods) very difficult and sometimes impossible. Hence we are exploring the use of nonlinear Krylov techniques (such as CMRES and Bi-CGSTAB) to accelerate and stabilize the existing solver. This strategy allows us to take advantage of the problem-definition capabilities of the existing solver. The overall approach amounts to using the SIMPLE (Semi-Implicit Method for Pressure-Linked Equations) method and its variants as nonlinear preconditioners for the nonlinear Krylov method. We have also adapted a backtracking approach for inexact Newton methods to damp the Newton step in the nonlinear Krylov method. This will be a report on work in progress. Preliminary results with nonlinear GMRES have been very encouraging: in many cases the number of line Gauss-Seidel sweeps has been reduced by about a factor of 5, and increased robustness of the underlying solver has also been observed.

  2. CHEMICAL COMPOSITION AND in vitro GAS PRODUCTION OF SOME LEGUME BROWSE SPECIES IN SUBTROPICAL AREAS OF MEXICO

    Directory of Open Access Journals (Sweden)

    Carlos A Garcia Montes de Oca

    2011-03-01

    Full Text Available The objective of the present study was to determine the chemical composition and in vitro gas production of different legume and wild arboreal pods. Seven seeds of legume browse species, Mexican calabash (Crescentia alata, esculent leadtree (Leucaena esculenta, guamuchil (Phitecellobium dulce, bastard cedar (Guazuma ulmifolia, needle bush (Acacia farnesiana, mimosa (Mimosa sp. and elephant ear tree (Enterolobium cyclocarpum. Were evaluated for their chemical composition (g/kg DM and in vitro gas production pattern. Crude Protein was higher for L. esculenta (220 and lower for G. ulmifolia (70. Neutral and acid detergent fiber were higher for G. ulmifolia (687 and 554 and lower for A. farnesiana (267 and 176. Lignin was higher for Mimosa sp. (219 and lower for P. dulce (81. Total gas production (ml gas/g DM of P. dulce (187 and E. cyclocarpum (164 were higher (P

  3. Establishment and intra-/inter-laboratory validation of a standard protocol of reactive oxygen species assay for chemical photosafety evaluation.

    Science.gov (United States)

    Onoue, Satomi; Hosoi, Kazuhiro; Wakuri, Shinobu; Iwase, Yumiko; Yamamoto, Toshinobu; Matsuoka, Naoko; Nakamura, Kazuichi; Toda, Tsuguto; Takagi, Hironori; Osaki, Naoto; Matsumoto, Yasuhiro; Kawakami, Satoru; Seto, Yoshiki; Kato, Masashi; Yamada, Shizuo; Ohno, Yasuo; Kojima, Hajime

    2013-11-01

    A reactive oxygen species (ROS) assay was previously developed for photosafety evaluation of pharmaceuticals, and the present multi-center study aimed to establish and validate a standard protocol for ROS assay. In three participating laboratories, two standards and 42 coded chemicals, including 23 phototoxins and 19 nonphototoxic drugs/chemicals, were assessed by the ROS assay according to the standardized protocol. Most phototoxins tended to generate singlet oxygen and/or superoxide under UV-vis exposure, but nonphototoxic chemicals were less photoreactive. In the ROS assay on quinine (200 µm), a typical phototoxic drug, the intra- and inter-day precisions (coefficient of variation; CV) were found to be 1.5-7.4% and 1.7-9.3%, respectively. The inter-laboratory CV for quinine averaged 15.4% for singlet oxygen and 17.0% for superoxide. The ROS assay on 42 coded chemicals (200 µm) provided no false negative predictions upon previously defined criteria as compared with the in vitro/in vivo phototoxicity, although several false positives appeared. Outcomes from the validation study were indicative of satisfactory transferability, intra- and inter-laboratory variability, and predictive capacity of the ROS assay. Copyright © 2012 John Wiley & Sons, Ltd.

  4. Consideration on thermodynamic data for predicting solubility and chemical species of elements in groundwater. Part 1: Tc, U, Am

    Energy Technology Data Exchange (ETDEWEB)

    Yamaguchi, Tetsuji; Takeda, Seiji [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1999-01-01

    The solubility determines the release of radionuclides from waste form and is used as a source term in radionuclide migration analysis in performance assessment of radioactive waste repository. Complexations of radionuclides by ligands in groundwater affect the interaction between radionuclides and geologic media, thus affect their migration behavior. Thermodynamic data for Tc, Am and U were reviewed and compiled to be used for predicting the solubility and chemical species in groundwater. Thermodynamic data were reviewed with emphasis on the hydrolysis and carbonate complexation that can dominate the speciation in typical groundwater. Thermodynamic data for other species were selected based on existing database. Thermodynamic data for other important elements are under investigation, thus shown in an appendix for temporary use. (author)

  5. The physico-chemical I-131 species in the exhaust air of a boiling water reactor (BWR 5)

    International Nuclear Information System (INIS)

    Deuber, H.

    1984-02-01

    In a German boiling water reactor, the pysico-chemical I-131 species were determined in the plant exhaust and in the individual exhausts during four months. These measurements aimed in particular at determining the percentage and the source of the radiologically decisive elemental I-131 released to the environment. On an average 13% of the I-131 discharged with the plant exhaust consisted of elemental iodine. This was largely released with the exhausts from the reactor building and from the turbine building. The main component was organic-bound I. (orig./HP) [de

  6. Chemical species of iodine in some seaweeds. Pt. 2. Iodine-bound biological macromolecules

    International Nuclear Information System (INIS)

    Xiaolin Hou; Chifang Chai; Xiaojun Yan

    2000-01-01

    The distribution of iodine in various biological macromolecules in Sargassum kjellmanianum was studied using neutron activation analysis combined with chemical and biochemical separation techniques. The results indicate that iodine is mainly bound with protein, part of iodine with pigment and polyphenol, and little with polysaccharides, such as algin, fucoidan and cellulose. This result is significant for the mechanism of enriching iodine of algae and utilization of alga iodine. (author)

  7. The smell of change: warming affects species interactions mediated by chemical information

    Czech Academy of Sciences Publication Activity Database

    Sentis, Arnaud; Ramon-Portugal, F.; Brodeur, J.; Hemptinne, J.-L.

    2015-01-01

    Roč. 21, č. 10 (2015), s. 3586-3594 ISSN 1354-1013 Grant - others:European Social Fund(CZ) CZ.1.07/2.3.00/30.0049 Institutional support: RVO:60077344 Keywords : chemical communication * climate change * insects Subject RIV: EH - Ecology, Behaviour Impact factor: 8.444, year: 2015 http://onlinelibrary.wiley.com/doi/10.1111/gcb.12932/abstract

  8. CHEMICALS

    CERN Multimedia

    Medical Service

    2002-01-01

    It is reminded that all persons who use chemicals must inform CERN's Chemistry Service (TIS-GS-GC) and the CERN Medical Service (TIS-ME). Information concerning their toxicity or other hazards as well as the necessary individual and collective protection measures will be provided by these two services. Users must be in possession of a material safety data sheet (MSDS) for each chemical used. These can be obtained by one of several means : the manufacturer of the chemical (legally obliged to supply an MSDS for each chemical delivered) ; CERN's Chemistry Service of the General Safety Group of TIS ; for chemicals and gases available in the CERN Stores the MSDS has been made available via EDH either in pdf format or else via a link to the supplier's web site. Training courses in chemical safety are available for registration via HR-TD. CERN Medical Service : TIS-ME :73186 or service.medical@cern.ch Chemistry Service : TIS-GS-GC : 78546

  9. Study of the chemical species of fluorine 18 produced by neutron irradiation of lithium aluminate

    International Nuclear Information System (INIS)

    Jimenez-Becerril, J.

    1990-01-01

    In the present work, the chemical form of fluorine-18 obtained by means of the neutron irradiated lithium aluminate was studied, in order to know its chemical behavior and to observe if it volatilizes and adheres to the walls of a tritium distillation system; for this matter paper chromatography and high voltage electrophoresis techniques were used. Lithium aluminate was synthetized, being characterized as LiAlO 2 which was irradiated with neutrons in order to produce fluorine-18. Lithium aluminate is a non-soluble solid, therefore fluorine produced may not be extracted, unless it is dissolved or extracted through the solid. So as not affect in a drastic way the chemical form, it was submitted to extraction processes, agitating the irradiated samples with different acids and basic solutions in order to analyze fluorine-18. The best extraction agent was found to be HCl, where two forms of fluorine-18 were found, one at the point of application, probably as a complex hexafluoride-aluminate and the other as a characteristic Rf of the fluorine ion. In the tritium distillation with helium as a carrier of a sample irradiated and heated up to 220-250 o C, no volatile types of fluorine-18 were found, thus it can be considered that in commercial production of tritium by means of neutron irradiation of lithium aluminate, fluorine-18 is not a damaging pollutant of the equipment pipe system. (Author)

  10. Modeling the partitioning of organic chemical species in cloud phases with CLEPS (1.1)

    Science.gov (United States)

    Rose, Clémence; Chaumerliac, Nadine; Deguillaume, Laurent; Perroux, Hélène; Mouchel-Vallon, Camille; Leriche, Maud; Patryl, Luc; Armand, Patrick

    2018-02-01

    The new detailed aqueous-phase mechanism Cloud Explicit Physico-chemical Scheme (CLEPS 1.0), which describes the oxidation of isoprene-derived water-soluble organic compounds, is coupled with a warm microphysical module simulating the activation of aerosol particles into cloud droplets. CLEPS 1.0 was then extended to CLEPS 1.1 to include the chemistry of the newly added dicarboxylic acids dissolved from the particulate phase. The resulting coupled model allows the prediction of the aqueous-phase concentrations of chemical compounds originating from particle scavenging, mass transfer from the gas-phase and in-cloud aqueous chemical reactivity. The aim of the present study was more particularly to investigate the effect of particle scavenging on cloud chemistry. Several simulations were performed to assess the influence of various parameters on model predictions and to interpret long-term measurements conducted at the top of Puy de Dôme (PUY, France) in marine air masses. Specific attention was paid to carboxylic acids, whose predicted concentrations are on average in the lower range of the observations, with the exception of formic acid, which is rather overestimated in the model. The different sensitivity runs highlight the fact that formic and acetic acids mainly originate from the gas phase and have highly variable aqueous-phase reactivity depending on the cloud acidity, whereas C3-C4 carboxylic acids mainly originate from the particulate phase and are supersaturated in the cloud.

  11. Measurements of non-reacting and reacting flow fields of a liquid swirl flame burner

    Science.gov (United States)

    Chong, Cheng Tung; Hochgreb, Simone

    2015-03-01

    The understanding of the liquid fuel spray and flow field characteristics inside a combustor is crucial for designing a fuel efficient and low emission device. Characterisation of the flow field of a model gas turbine liquid swirl burner is performed by using a 2-D particle imaging velocimetry(PIV) system. The flow field pattern of an axial flow burner with a fixed swirl intensity is compared under confined and unconfined conditions, i.e., with and without the combustor wall. The effect of temperature on the main swirling air flow is investigated under open and non-reacting conditions. The result shows that axial and radial velocities increase as a result of decreased flow density and increased flow volume. The flow field of the main swirling flow with liquid fuel spray injection is compared to non-spray swirling flow. Introduction of liquid fuel spray changes the swirl air flow field at the burner outlet, where the radial velocity components increase for both open and confined environment. Under reacting condition, the enclosure generates a corner recirculation zone that intensifies the strength of radial velocity. The reverse flow and corner recirculation zone assists in stabilizing the flame by preheating the reactants. The flow field data can be used as validation target for swirl combustion modelling.

  12. Chemically emulsified crude oil as substrate for bacterial oxidation : differences in species response

    International Nuclear Information System (INIS)

    Bruheim, P.; Eimhjellen, K.

    1998-01-01

    The ability of bacterial species to oxidize alkanes in crude oil in water emulsions was studied. Alkanes in crude oil need specific physiological adaptations to the microorganisms. Synthesis of biosurfactants has been considered as a prerequisite for either specific adhesion mechanisms to large oil drops or emulsification of oil followed by uptake of submicron oil droplets. In this study four bacterial species were tested. Emulsions were prepared by nonionic sorbitan ester and polyoxyethylene ether surfactants. The oxidation rates were measured. Both positive and negative effects of surfactant amendments were observed. The same surfactant affected different bacteria in different ways. The response to the surfactant amendment depended on the physiological state of the bacteria. The results showed that surfactants resulted in decreased cell adhesion to the oil phase for all the bacteria. 19 refs., 3 tabs., 4 figs

  13. Antimicrobial activity and chemical constituents of essential oils and oleoresins extracted from eight pepper species

    Directory of Open Access Journals (Sweden)

    Laira Martinelli

    Full Text Available ABSTRACT: Essential oils are the most important compounds produced during secondary metabolism in aromatic plants. Essential oils are volatile, have characteristic odor and are used as defensive agents by plants. In pepper, it is possible to say that essential oils are the “flavor fingerprint” of each species. In the present article, eight species of pepper were studied in order to extract their essential oils and oleoresins, test their antibacterial and antifungal activities and also to identify the compounds present in the most bioactive samples. Results demonstrated that two essential oils [Pimenta dioica (L. Merr. and Schinus terebinthifolius] and three oleoresins (Schinus terebinthifolius and Piper nigrum white and black recorded significant antimicrobial activity. These active essential oils and oleoresins are interesting for use in biotechnological processes employed in food, pharmaceutical and other industries.

  14. A High Throughput Ambient Mass Spectrometric Approach to Species Identification and Classification from Chemical Fingerprint Signatures

    OpenAIRE

    Musah, Rabi A.; Espinoza, Edgard O.; Cody, Robert B.; Lesiak, Ashton D.; Christensen, Earl D.; Moore, Hannah E.; Maleknia, Simin; Drijfhout, Falko P.

    2015-01-01

    A high throughput method for species identification and classification through chemometric processing of direct analysis in real time (DART) mass spectrometry-derived fingerprint signatures has been developed. The method entails introduction of samples to the open air space between the DART ion source and the mass spectrometer inlet, with the entire observed mass spectral fingerprint subjected to unsupervised hierarchical clustering processing. A range of both polar and non-polar chemotypes a...

  15. Portuguese Thymbra and Thymus species volatiles: chemical composition and biological activities.

    Science.gov (United States)

    Figueiredo, A C; Barroso, J G; Pedro, L G; Salgueiro, L; Miguel, M G; Faleiro, M L

    2008-01-01

    Thymbra capitata and Thymus species are commonly known in Portugal as thyme and they are currently used as culinary herbs, as well as for ornamental, aromatizing and traditional medicinal purposes. The present work reports on the state of the art on the information available on the taxonomy, ethnobotany, cell and molecular biology of the Portuguese representatives of these genera and on the chemotaxonomy and antibacterial, antifungal and antioxidant activities of their essential oils and other volatile-containing extracts.

  16. CHEMICAL RISKS TO THREATENED AND ENDANGERED FISH SPECIES AT CONCENTRATIONS BELOW WATER QUALITY CRITERIA: IS IT FEASIBLE TO ENSURE PROTECTION OF INDIVIDUALS

    Science.gov (United States)

    The USGS Laboratory in Columbia, Missouri has evaluated the acute sensitivities of 17 threatened and endangered fish species (including three salmonids), to five different chemicals (carbaryl, copper, 4-nonylphenol, pentachlorophenol, and permethrin). The results of these studie...

  17. Chemical constituents variations of essential oils from rhizomes of four Zingiberaceae species

    International Nuclear Information System (INIS)

    Sukari, M.A.; Mohd Sharif, N.W.; Yap, A.L.C.; Tang, S.W.; Rahmani, M.; Ee, G.C.L.; Taufiq-Yap, Y.H.; Yusof, U.K.

    2008-01-01

    The essential oils were extracted using the hydrodistillation method from four Zingiberaceae species; Zingiber officinale var.rubrum, Zingiber amaricans, Kaempferia galanga, and Boesenbergia pandurata. Volatile components of all extracts were analyzed by gas chromatography-mass spectrometry (GC-MS) techniques. The major constituents of Zingiber officinale, Zingiber amaricans, Kaempferia galanga, and Boesenbergia pandurata were identified as E-citral (20.98%), zerumbone (40.70%), ethyl p -methoxycinnamate (58.47%) and camphor (57.97%), respectively. Kaempferia galanga and Zingiber amaricans were rich in sesquiterpenes whereas Boesenbergia pandurata and Zingiber officinale var. rubrum contained mostly monoterpenes. (author)

  18. Welding fumes from stainless steel gas metal arc processes contain multiple manganese chemical species.

    Science.gov (United States)

    Keane, Michael; Stone, Samuel; Chen, Bean

    2010-05-01

    Fumes from a group of gas metal arc welding (GMAW) processes used on stainless steel were generated using three different metal transfer modes and four different shield gases. The objective was to identify and measure manganese (Mn) species in the fumes, and identify processes that are minimal generators of Mn species. The robotic welding system was operated in short-circuit (SC) mode (Ar/CO2 and He/Ar), axial spray (AXS) mode (Ar/O2 and Ar/CO2), and pulsed axial-spray (PAXS) mode (Ar/O2). The fumes were analyzed for Mn by a sequential extraction process followed by inductively coupled plasma-atomic emission spectroscopy (ICP-AES) analysis, and by X-ray diffraction (XRD). Total elemental Mn, iron (Fe), chromium (Cr) and nickel (Ni) were separately measured after aqua regia digestion and ICP-AES analysis. Soluble Mn2+, Fe2+, Fe3+, and Ni2+ in a simple biological buffer (phosphate-buffered saline) were determined at pH 7.2 and 5.0 after 2 h incubation at 37 C by ion chromatography. Results indicate that Mn was present in soluble form, acid-soluble form, and acid-soluble form after reduction by hydroxylamine, which represents soluble Mn0 and Mn2+ compounds, other Mn2+ compounds, and (Mn3+ and Mn4+) compounds, respectively. The dominant fraction was the acid-soluble Mn2+ fraction, but results varied with the process and shield gas. Soluble Mn mass percent in the fume ranged from 0.2 to 0.9%, acid-soluble Mn2+ compounds ranged from 2.6 to 9.3%, and acid plus reducing agent-soluble (Mn3+ and Mn4+) compounds ranged from 0.6 to 5.1%. Total Mn composition ranged from 7 to 15%. XRD results showed fumes had a crystalline content of 90-99% Fe3O4, and showed evidence of multiple Mn oxides, but overlaps and weak signals limited identification. Small amounts of the Mn2+ in the fume (welding process. Mn generation rates for the fractions were tabulated, and the influence of ozone is discussed. The conclusions are that exposures to welding fumes include multiple Mn species, both

  19. Chemical Characterization and Antioxidant Potential of Wild Ganoderma Species from Ghana.

    Science.gov (United States)

    Obodai, Mary; Mensah, Deborah L Narh; Fernandes, Ângela; Kortei, Nii Korley; Dzomeku, Matilda; Teegarden, Matthew; Schwartz, Steven J; Barros, Lillian; Prempeh, Juanita; Takli, Richard K; Ferreira, Isabel C F R

    2017-01-25

    The chemical characterization and antioxidant potential of twelve wild strains of Ganoderma sp. from Ghana, nine (LS1-LS9) of which were found growing wild simultaneously on the same dying Delonix regia tree, were evaluated. Parameters evaluated included the nutritional value, composition in sugars, fatty acids, phenolic and other organic compounds and some vitamins and vitamin precursors. Antioxidant potential was evaluated by investigating reducing power, radical scavenging activity and lipid peroxidation inhibition using five in vitro assays. Protein, carbohydrate, fat, ash and energy contents ranged between 15.7-24.5 g/100 g·dw, 73.31-81.90 g/100 g, 0.48-1.40 g/100 g, 0.68-2.12 g/100 g ash and 396.1-402.02 kcal/100 g, respectively. Fatty acids such as linoleic, oleic and palmitic acids were relatively abundant. Free sugars included rhamnose, fructose, mannitol, sucrose and trehalose. Total tocopherols, organic acids and phenolic compounds' content ranged between 741-3191 µg/100 g, 77-1003 mg/100 g and 7.6-489 µg/100 g, respectively. There were variations in the β-glucans, ergosterol and vitamin D₂ contents. The three major minerals in decreasing order were K > P > S. Ganoderma sp. strain AM1 showed the highest antioxidant activity. This study reveals, for the first time, chemical characteristics of Ganoderma spp. which grew simultaneously on the same tree.

  20. Chemical Composition of Essential Oils of Xanthium spinosum L., an Invasive Species of Corsica.

    Science.gov (United States)

    Andreani, Stéphane; Paolini, Julien; Costa, Jean; Muselli, Alain

    2017-01-01

    Xanthium spinosum L. is a highly invasive plant originated from South America throughout the world as well as in Corsica Island. The chemical composition of X. spinosum essential oils from 25 Corsican locations was investigated using GC-FID and GC/MS. Seventy-four components, which accounted for 96.2% of the total amount, were reported for the first time in the essential oil from aerial parts. The main compounds were eudesma-4(14),7-dien-1β-ol (61; 21.3%), germacrene D (36; 8.8%) and cadalene (60; 8.7%). Comparison with the literature highlighted the originality of the Corsican essential oil and eudesma-4(14),7-dien-1β-ol could be used as taxonomical marker to the systematics of the Xanthium genus. The essential oils obtained from separate organs and during the plant vegetative cycle were also studied to gain more knowledge about the correlations between the volatile production and the phenological states of this weed. The production of oxygenated sesquiterpenes was predominant during the plant-flowering process. The study focuses on direct correlation between the chemical composition of individual 25 oil samples and the morphological differences of the plant. Our results have gained more knowledge about the secondary metabolite production that occurs during the plant life, they could be interesting in order to manage the dispersal of X. spinosum. © 2017 Wiley-VHCA AG, Zurich, Switzerland.

  1. IMPACT OF WOODY PLANTS SPECIES ON SOIL PHYSIO-CHEMICAL PROPERTIES ALONG GRAZING GRADIENTS IN RANGELANDS OF EASTERN ETHIOPIA

    Directory of Open Access Journals (Sweden)

    Mohammed Mussa Abdulahi

    2016-12-01

    Full Text Available In the lowlands of arid and semiarid rangelands woody plants plays an important role in soil fertility maintenance, providing food, medicine, cosmetics, fodder, fuel wood and pesticides. A better understanding of the interaction of woody plants on their immediate environment is needed to guide optimum management of native vegetation in the production landscapes. However, the impact of woody plant species on soil properties remains poorly understood. This study evaluates the impact of two dominant woody plant species (A. senegal and B. aegyptica on soil physico-chemical properties along grazing gradients in rangelands of eastern Ethiopia. Six trees of each species were selected from light, moderate and heavy grazing sites.  Soil sample data at two depths (0-15 and 16-30 cm were collected from under and open areas of A. senegal and B. aegyptica from each grazing sites, and analysed for nutrient contents. The nutrient status of soil under both woody species was significantly higher especially with regard to soil organic matter (4.37%, total nitrogen (0.313%, and available phosphorus (11.62 than the open grassland with soil organic matter (3.82%, total nitrogen (0.246%, and available phosphorus (10.94 mg/Kg soil for A. Senegal. The soil organic matter (3.93%, total nitrogen (0.285%, available phosphorus (11.66 mg/Kg soil were significantly higher than open grassland with soil organic matter (3.52%, total nitrogen (0.218%, available phosphorus (10.73 mg/Kg soil for B. aegyptica. This was more pronounced in the top 15 cm of soil under A. senegal woody plant species and on the light and moderate grazing site. Therefore, this tree has a significant effect on soil fertility improvement in resource poor rangelands and as a result, it is important to retain scattered A. senegal and B. aegyptica plants in the lowlands of eastern Ethiopia.

  2. The Atmospheric Tomography Mission (ATom): Comparing the Chemical Climatology of Reactive Species and Air Parcels from Measurements and Global Models

    Science.gov (United States)

    Prather, M. J.; Flynn, C.; Wennberg, P. O.; Kim, M. J.; Ryerson, T. B.; Hanisco, T. F.; Diskin, G. S.; Daube, B. C.; Commane, R.; McKain, K.; Apel, E. C.; Blake, N. J.; Blake, D. R.; Elkins, J. W.; Hall, S.; Steenrod, S.; Strahan, S. E.; Lamarque, J. F.; Fiore, A. M.; Horowitz, L. W.; Murray, L. T.; Mao, J.; Shindell, D. T.; Wofsy, S. C.

    2017-12-01

    The NASA Atmospheric Tomography Mission (ATom) is building a photochemical climatology of the remote troposphere based on objective sampling and profiling transects over the Pacific and Atlantic Oceans. These statistics provide direct tests of chemistry-climate models. The choice of species focuses on those controlling primary reactivity (a.k.a. oxidative state) of the troposphere, specifically chemical tendencies of O3 and CH4. These key species include, inter alia, O3, CH4, CO, C2H6, other alkanes, alkenes, aromatics, NOx, HNO3, HO2NO2, PAN, other organic nitrates, H2O, HCHO, H2O2, CH3OOH. Three of the four ATom deployments are now complete, and data from the first two (ATom-1 & -2) have been released as of this talk (see espoarchive.nasa.gov/archive/browse/atom). The statistical distributions of key species are presented as 1D and 2D probability densities (PDs) and we focus here on the tropical and mid-latitude regions of the Pacific during ATom-1 (Aug) and -2 (Feb). PDs are computed from ATom observations and 6 global chemistry models over the tropospheric depth (0-12 km) and longitudinal extent of the observations. All data are weighted to achieve equal mass-weighting by latitude regimes to account for spatial sampling biases. The models are used to calculate the reactivity in each ATom air parcel. Reweighting parcels with loss of CH4 or production of O3, for example, allows us to identify which air parcels are most influential, including assessment of the importance of fine pollution layers in the most remote troposphere. Another photochemical climatology developed from ATom, and used to test models, includes the effect of clouds on photolysis rates. The PDs and reactivity-weighted PDs reveal important seasonal differences and similarities between the two campaigns and also show which species may be most important in controlling reactivities. They clearly identify some very specific failings in the modeled climatologies and help us evaluate the chemical

  3. Chromatographic speciation of Cr(III)-species, inter-species equilibrium isotope fractionation and improved chemical purification strategies for high-precision isotope analysis.

    Science.gov (United States)

    Larsen, K K; Wielandt, D; Schiller, M; Bizzarro, M

    2016-04-22

    Chromatographic purification of chromium (Cr), which is required for high-precision isotope analysis, is complicated by the presence of multiple Cr-species with different effective charges in the acid digested sample aliquots. The differing ion exchange selectivity and sluggish reaction rates of these species can result in incomplete Cr recovery during chromatographic purification. Because of large mass-dependent inter-species isotope fractionation, incomplete recovery can affect the accuracy of high-precision Cr isotope analysis. Here, we demonstrate widely differing cation distribution coefficients of Cr(III)-species (Cr(3+), CrCl(2+) and CrCl2(+)) with equilibrium mass-dependent isotope fractionation spanning a range of ∼1‰/amu and consistent with theory. The heaviest isotopes partition into Cr(3+), intermediates in CrCl(2+) and the lightest in CrCl2(+)/CrCl3°. Thus, for a typical reported loss of ∼25% Cr (in the form of Cr(3+)) through chromatographic purification, this translates into 185 ppm/amu offset in the stable Cr isotope ratio of the residual sample. Depending on the validity of the mass-bias correction during isotope analysis, this further results in artificial mass-independent effects in the mass-bias corrected (53)Cr/(52)Cr (μ(53)Cr* of 5.2 ppm) and (54)Cr/(52)Cr (μ(54)Cr* of 13.5 ppm) components used to infer chronometric and nucleosynthetic information in meteorites. To mitigate these fractionation effects, we developed strategic chemical sample pre-treatment procedures that ensure high and reproducible Cr recovery. This is achieved either through 1) effective promotion of Cr(3+) by >5 days exposure to HNO3H2O2 solutions at room temperature, resulting in >∼98% Cr recovery for most types of sample matrices tested using a cationic chromatographic retention strategy, or 2) formation of Cr(III)-Cl complexes through exposure to concentrated HCl at high temperature (>120 °C) for several hours, resulting in >97.5% Cr recovery using a

  4. Propel: A Discontinuous-Galerkin Finite Element Code for Solving the Reacting Navier-Stokes Equations

    Science.gov (United States)

    Johnson, Ryan; Kercher, Andrew; Schwer, Douglas; Corrigan, Andrew; Kailasanath, Kazhikathra

    2017-11-01

    This presentation focuses on the development of a Discontinuous Galerkin (DG) method for application to chemically reacting flows. The in-house code, called Propel, was developed by the Laboratory of Computational Physics and Fluid Dynamics at the Naval Research Laboratory. It was designed specifically for developing advanced multi-dimensional algorithms to run efficiently on new and innovative architectures such as GPUs. For these results, Propel solves for convection and diffusion simultaneously with detailed transport and thermodynamics. Chemistry is currently solved in a time-split approach using Strang-splitting with finite element DG time integration of chemical source terms. Results presented here show canonical unsteady reacting flow cases, such as co-flow and splitter plate, and we report performance for higher order DG on CPU and GPUs.

  5. Chemical composition of particles from traditional burning of Pakistani wood species

    Science.gov (United States)

    Shahid, Imran; Kistler, Magdalena; Mukhtar, Azam; Ramirez-Santa Cruz, Carlos; Bauer, Heidi; Puxbaum, Hans

    2015-11-01

    Total particulate matter (TPM) emitted during burning of three types of Pakistani wood (eucalyptus camaldulensis, local name Safeeda; acacia nilotica, local name Kikar, Babul; dalbergia sissoo, Shisham, Tali) in a traditional brick stove were collected and analyzed for anhydrosugars, sugar alcohols, trace metals, soluble ions and carbonaceous species. This is a first study reporting anhydrosugars in wood smoke particles emitted during traditional burning of common wood types in Pakistan. Carbonaceous species showed the highest contribution to the particulate matter. Although the total carbon (TC) contribution was similar for all burnings (64.8-70.2%), the EC/OC ratio varied significantly, from 0.2 to 0.3 for Accacia and Dalbergia to 0.7-0.8 for Eucalyptus and Wood-mix. Among inorganic constituents potassium chloride and silicon were found at levels higher than 1%. The levoglucosan concentrations ranged from 3.0 to 6.6% (average 5.6%) with the highest value for Accacia and lowest value for the wood-mix. The high levoglucosan/mannosan ratios of 20-28 were typical for hardwood. The ratio between levoglucosan and galactosan varied stronger and was found to be around 13-20 for Accacia, Eucalyptus and Wood mix, and 43 for Dalbergia. The determined levoglucosan concentrations allowed assessing the conversion factor for calculation of biomass smoke contribution to ambient particulate matter levels in Pakistan.

  6. Natural Chemical Composition of Commercial Fish Species: Characterisation of Pangasius, Wild and Farmed Turbot and Barramundi

    Science.gov (United States)

    Manthey-Karl, Monika; Lehmann, Ines; Ostermeyer, Ute; Schröder, Ute

    2016-01-01

    To comply with the relevant legal requirements and correct labelling, it is necessary for business operators and inspection authorities to know the natural characteristics of the raw material. This study gives a comprehensive overview of muscle flesh composition of farmed and wild Atlantic turbot (Scophthalmus maximus) and barramundi (Lates calcarifer) and of farmed pangasius (Pangasianodon hypophthalmus). The proximate composition, di- and triphosphates and citric acid values are presented in order to evaluate possible indicators for a hidden treatment during processing to fillets. All moisture contents were ≤80%. Even for pangasius, protein values for deep skinned fillets of ≥18% were determined. Only small quantities of naturally occurring citric acid (up to 0.03 g·kg−1) were detectable. The lipid content was the most varying main component within the different species, ranging between 1.2% to 2.0% and 0.3% to 3.0% for farmed turbot and barramundi, respectively. Pangasius flesh had a mean lipid content of 7.8%. Trimming and separation of the red layer reduced the lipid content of the commercially sold white-flesh fillets to 2.7% to 3.5%. Fatty acids profiles, free amino acids, and minerals were analysed to show the nutritional quality of the aquaculture fish species and compared to wild turbot and barramundi. Despite some natural variation, these components can be considered as comparable. PMID:28231154

  7. Chemical and Biological Analyses of the Essential Oils and Main Constituents of Piper Species

    Directory of Open Access Journals (Sweden)

    Leonor Laura Leon

    2012-02-01

    Full Text Available The essential oils obtained from leaves of Piper duckei and Piper demeraranum by hydrodistillation were analyzed by gas chromatography-mass spectrometry. The main constituents found in P. demeraranum oil were limonene (19.3% and β-elemene (33.1% and in P. duckei oil the major components found were germacrene D (14.7% and trans-caryophyllene (27.1%. P. demeraranum and P. duckei oils exhibited biological activity, with IC50 values between 15 to 76 μg mL−1 against two Leishmania species, P. duckei oil being the most active. The cytotoxicity of the essential oils on mice peritoneal macrophage cells was insignificant, compared with the toxicity of pentamidine. The main mono- and sesquiterpene, limonene (IC50 = 278 μM and caryophyllene (IC50 = 96 μM, were tested against the strains of Leishmania amazonensis, and the IC50 values of these compounds were lower than those found for the essential oils of the Piper species. The HET-CAM test was used to evaluate the irritation potential of these oils as topical products, showing that these oils can be used as auxiliary medication in cases of cutaneous leishmaniasis, with less side effects and lower costs.

  8. Natural Chemical Composition of Commercial Fish Species: Characterisation of Pangasius, Wild and Farmed Turbot and Barramundi

    Directory of Open Access Journals (Sweden)

    Monika Manthey-Karl

    2016-08-01

    Full Text Available To comply with the relevant legal requirements and correct labelling, it is necessary for business operators and inspection authorities to know the natural characteristics of the raw material. This study gives a comprehensive overview of muscle flesh composition of farmed and wild Atlantic turbot (Scophthalmus maximus and barramundi (Lates calcarifer and of farmed pangasius (Pangasianodon hypophthalmus. The proximate composition, di- and triphosphates and citric acid values are presented in order to evaluate possible indicators for a hidden treatment during processing to fillets. All moisture contents were ≤80%. Even for pangasius, protein values for deep skinned fillets of ≥18% were determined. Only small quantities of naturally occurring citric acid (up to 0.03 g·kg−1 were detectable. The lipid content was the most varying main component within the different species, ranging between 1.2% to 2.0% and 0.3% to 3.0% for farmed turbot and barramundi, respectively. Pangasius flesh had a mean lipid content of 7.8%. Trimming and separation of the red layer reduced the lipid content of the commercially sold white-flesh fillets to 2.7% to 3.5%. Fatty acids profiles, free amino acids, and minerals were analysed to show the nutritional quality of the aquaculture fish species and compared to wild turbot and barramundi. Despite some natural variation, these components can be considered as comparable.

  9. Screening of Chemical Composition, Antioxidant and Anticholinesterase Activity of Section Brevifilamentum of Origanum (L. Species

    Directory of Open Access Journals (Sweden)

    Hasibe Yılmaz

    2017-09-01

    Full Text Available Six Origanum species, Origanum acutidens (Hand. -Mazz. Ietsw. (OA, Origanum brevidens (Bornm. Dinsm. (OB, Origanum haussknechtii Boiss. (OC, Origanum husnucan-baseri H.Duman, Aytaç & A.Duran (OHB, Origanum leptocladum Boiss. (OL, Origanum rotundifolium Boiss. (OR, belonging to sect. Brevifilamentum were analyzed for their essential oil and phenolic components. For the essential oil analyses, GC-MS and GC-FID were used. Phenolic contents of the aerial parts of the chloroform, acetone, and methanol extracts were analyzed using LC-MS/MS. Antioxidant activity of the species was investigated by three methods; DPPH free radical scavenging activity, β-carotene linoleic acid assays and CUPRAC assays. Also, acetyl and butyrylcholinesterase inhibition of the extracts were investigated. While the essential oil contents of the section Brevifilamentum showed difference in chemotype, the phenolic contents were found to be coumaric acids and derivatives. These groups were the most abundant components of the extracts. Especially rosmarinic acid was detected in high amounts in acetone and methanol extracts. OA had the best activity both in antioxidant and anticholinesterase assays.

  10. Species delimitation and evolution in morphologically and chemically diverse communities of the lichen-forming genus Xanthoparmelia (Parmeliaceae, Ascomycota) in western North America.

    Science.gov (United States)

    Leavitt, Steven D; Johnson, Leigh; St Clair, Larry L

    2011-02-01

    Accurate species delimitation is important for understanding the diversification of biota and has critical implications for ecological and conservation studies. However, a growing body of evidence indicates that morphology-based species circumspection in lichenized fungi misrepresents fungal diversity. The foliose lichen genus Xanthoparmelia includes over 800 species displaying a complex array of morphological and secondary metabolite diversity. We used a multifaceted approach, applying phylogenetic, population genetic, and genealogical analyses to delimit species in a single well-supported monophyletic clade containing 10 morphologically and chemically diverse Xanthoparmelia species in western North America. Sequence data from four ribosomal and two low-copy, protein-coding markers, along with chemical and morphological data were used to assess species diversity. We found that traditionally circumscribed species are not supported by molecular data. Rather, all sampled taxa were better represented by three polymorphic population clusters. Our results suggest that secondary metabolite variation may have limited utility in diagnosing lineages within this group, while identified populations clusters did not reflect major phylogeographic or ecological patterns. In contrast to studies revealing previously undiscovered fungal lineages masked within lichen species circumscribed by traditional morphological and chemical concepts, the present study suggests that species diversity has been overestimated in the species-rich genus Xanthoparmelia.

  11. Influence of reactions heats on variation of radius, temperature, pressure and chemical species amounts within a single acoustic cavitation bubble.

    Science.gov (United States)

    Kerboua, Kaouther; Hamdaoui, Oualid

    2018-03-01

    The scientific interest toward the study of acoustic bubble is mainly explained by its practical benefit in providing a reactional media favorable to the rapid evolution of chemical mechanism. The evolution of this mechanism is related to the simultaneous and dependent variation of the volume, temperature and pressure within the bubble, retrieved by the resolution of a differential equations system, including among others the thermal balance. This last one is subject to different assumptions, some authors deem simply that the temperature varies adiabatically during the collapsing phase, without considering the reactions heat of the studied mechanism. This paper aims to evaluate the pertinence of neglecting reactions heats in the thermal balance, by analyzing their effect on the variation of radius, temperature, pressure and chemical species amounts. The results show that the introduction of reactions heats conducts to a decrease of the temperature, an increase of the pressure and a reduction of the bubble volume. As a consequence, this leads to a drop of the quantities of free radicals produced by the chemical mechanism evolving within the bubble. This paper also proved that the impact of the consideration of reactions heats is dependent of the frequency and the acoustic amplitude of the ultrasonic wave. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. Chemical dissolution of spent fuel and cladding using complexed fluoride species

    International Nuclear Information System (INIS)

    Rance, P.J.W.; Freeman, G.A.; Mishin, V.; Issoupov, V.

    2001-01-01

    The dissolution of LWR fuel cladding using two fluoride ion donors, HBF 4 and K 2 ZrF 6 , in combination with nitric acid has been investigated as a potential reprocessing head-end process suitable for chemical decladding and fuel dissolution in a single process step. Maximum zirconium concentrations in the order of 0,75 to 1 molar have been achieved and dissolution found to continue to low F:Zr ratios albeit at ever decreasing rates. Dissolution rates of un-oxidised zirconium based fuel claddings are fast, whereas oxidised materials exhibit an induction period prior to dissolution. Data is presented relating to the rates of dissolution of cladding and UO 2 fuels under various conditions. (author)

  13. Chemical composition and biological activities of the essential oils from two Pereskia species grown in Brazil.

    Science.gov (United States)

    Souza, Lucéia Fatima; De Barros, Ingrid Bergman Inchausti; Mancini, Emilia; De Martino, Laura; Scandolera, Elia; De Feo, Vincenzo

    2014-12-01

    The chemical composition of the essential oils of Pereskia aculeata Mill. and P. grandifolia Haw. (Cactaceae), grown in Brazil, was studied by means of GC and GC-MS. In all, 37 compounds were identified, 30 for P. aculeata and 15 for P. grandifolia. Oxygenated diterpenes are the main constituents, both in the oil ofP. grandifolia (55.5%) and in that ofP. aculeata (29.4%). The essential oils were evaluated for their in vitro phytotoxic activity against germination and initial radicle growth of Raphanus sativus L., Sinapis arvensis L., and Phalaris canariensis L. seeds. The essential oil of P. grandifolia, at all doses tested, significantly inhibited the radicle elongation of R. sativus. Moreover, the antimicrobial activity of the essential oils was assayed against ten bacterial strains. The essential oils showed weak inhibitory activity against the Gram-positive pathogens.

  14. Future Needs and Recommendations in the Development of Species Sensitivity Distributions: Estimating Toxicity Thresholds for Aquatic Ecological Communities and Assessing Impacts of Chemical Exposures

    Science.gov (United States)

    A species sensitivity distribution (SSD) is a probability model of the variation of species sensitivities to a stressor, in particular chemical exposure. The SSD approach has been used as a decision support tool in environmental protection and management since the 1980s, and the ...

  15. Aquatic plants: Test species sensitivity and minimum data requirement evaluations for chemical risk assessments and aquatic life criteria development for the USA

    Science.gov (United States)

    Phytotoxicity results from the publicly-available ECOTOX database were summarized for 20 chemicals and 188 aquatic plants to determine species sensitivities and the ability of a species-limited toxicity data set to serve as a surrogate for a larger data set. The lowest effect con...

  16. New applications in EPA’s ECOTOX Knowledge System: Assimilating relative potencies of metals across chemical and biological species from literature-based toxicity effects data.

    Science.gov (United States)

    Toxicity of metals in field settings can vary widely among ionic chemical species and across biological receptors. Thus, a challenge often found in developing TRVs for the risk assessment of metals is identifying the most appropriate metal and biological species combinations for...

  17. Chemical Constituents and Structural Characterization of Polysaccharides from Four Typical Bamboo Species Leaves

    Directory of Open Access Journals (Sweden)

    Cheng-Zhang Wang

    2015-03-01

    Full Text Available In order to find bamboo leaves with high contents of bioactive polysaccharides, 32 samples were chosen to analyze their polysaccharide content by GC and sulfuric acid-anthrone colorimetric assays. Purified polysaccharides (BLPS were separated from the four varieties P. nigra (Lodd. Munro (PN, P. vivax McClure (PV, Chimonobambusa quadrangularis (Fenzi Makino (CQ, and P. bambussoides cv. Tanakae (PB by ultrasound extraction, solution precipitation, ion exchange resin, DEAE-52 and Sephadex G-100 chromatography. BLPS structural characterization was accomplished by HPLC-GPC, Fourier transform infra-red spectroscopy (FTIR and NaIO4-HIO4 oxidation reactions. The results showed that the total polysaccharides of the bamboo leaves in samples 1–32 ranged between 1.4% and 5.4%, Samples No. 29–No. 32 (PN, PV, CQ, and PB contained 2–3 fold more polysaccharides than No. 1~No. 28 among the 32 different species, particularly the content of galactose was in a range of 21.5%–34.1% for these four typical bamboo species leaves, which was also more than 2–3 fold higher than in No. 1–No. 28. Sugar analysis indicated that PN-PBLPS-1, PV-PBLPS-1, CQ-PBLPS-1 and PB-PBLPS-1 from the four varieties were homogeneous polysaccharides with molecular weights of 2.04 × 104, 1.15 × 104, 8.75 × 104 and 1.48 × 104 Da, respectively. PB-PBLPS-1 was a mixture of α-galactopyranose and β-d-glucopyranose linkages with α-(1→6 or β-(1→6glycosidic bonds, while PN-PBLPS-1, PV-PBLPS-1, and CQ-PBLPS-1 had α galactopyranose linkages with α-(1→6 glycosidic bonds.

  18. Turbulence-chemistry interactions in reacting flows

    Energy Technology Data Exchange (ETDEWEB)

    Barlow, R.S.; Carter, C.D. [Sandia National Laboratories, Livermore, CA (United States)

    1993-12-01

    Interactions between turbulence and chemistry in nonpremixed flames are investigated through multiscalar measurements. Simultaneous point measurements of major species, NO, OH, temperature, and mixture fraction are obtained by combining spontaneous Raman scattering, Rayleigh scattering, and laser-induced fluorescence (LIF). NO and OH fluorescence signals are converted to quantitative concentrations by applying shot-to-shot corrections for local variations of the Boltzmann fraction and collisional quenching rate. These measurements of instantaneous thermochemical states in turbulent flames provide insights into the fundamental nature of turbulence-chemistry interactions. The measurements also constitute a unique data base for evaluation and refinement of turbulent combustion models. Experimental work during the past year has focused on three areas: (1) investigation of the effects of differential molecular diffusion in turbulent combustion: (2) experiments on the effects of Halon CF{sub 3}Br, a fire retardant, on the structure of turbulent flames of CH{sub 4} and CO/H{sub 2}/N{sub 2}; and (3) experiments on NO formation in turbulent hydrogen jet flames.

  19. Intra-/inter-laboratory validation study on reactive oxygen species assay for chemical photosafety evaluation using two different solar simulators.

    Science.gov (United States)

    Onoue, Satomi; Hosoi, Kazuhiro; Toda, Tsuguto; Takagi, Hironori; Osaki, Naoto; Matsumoto, Yasuhiro; Kawakami, Satoru; Wakuri, Shinobu; Iwase, Yumiko; Yamamoto, Toshinobu; Nakamura, Kazuichi; Ohno, Yasuo; Kojima, Hajime

    2014-06-01

    A previous multi-center validation study demonstrated high transferability and reliability of reactive oxygen species (ROS) assay for photosafety evaluation. The present validation study was undertaken to verify further the applicability of different solar simulators and assay performance. In 7 participating laboratories, 2 standards and 42 coded chemicals, including 23 phototoxins and 19 non-phototoxic drugs/chemicals, were assessed by the ROS assay using two different solar simulators (Atlas Suntest CPS series, 3 labs; and Seric SXL-2500V2, 4 labs). Irradiation conditions could be optimized using quinine and sulisobenzone as positive and negative standards to offer consistent assay outcomes. In both solar simulators, the intra- and inter-day precisions (coefficient of variation; CV) for quinine were found to be below 10%. The inter-laboratory CV for quinine averaged 15.4% (Atlas Suntest CPS) and 13.2% (Seric SXL-2500V2) for singlet oxygen and 17.0% (Atlas Suntest CPS) and 7.1% (Seric SXL-2500V2) for superoxide, suggesting high inter-laboratory reproducibility even though different solar simulators were employed for the ROS assay. In the ROS assay on 42 coded chemicals, some chemicals (ca. 19-29%) were unevaluable because of limited solubility and spectral interference. Although several false positives appeared with positive predictivity of ca. 76-92% (Atlas Suntest CPS) and ca. 75-84% (Seric SXL-2500V2), there were no false negative predictions in both solar simulators. A multi-center validation study on the ROS assay demonstrated satisfactory transferability, accuracy, precision, and predictivity, as well as the availability of other solar simulators. Copyright © 2013 Elsevier Ltd. All rights reserved.

  20. Toxicity of proton-metal mixtures in the field: Linking stream macroinvertebrate species diversity to chemical speciation and bioavailability

    Energy Technology Data Exchange (ETDEWEB)

    Stockdale, Anthony [Centre for Ecology and Hydrology, Lancaster Environment Centre, Library Avenue, Bailrigg, Lancaster LA1 4AP (United Kingdom); Tipping, Edward, E-mail: et@ceh.ac.uk [Centre for Ecology and Hydrology, Lancaster Environment Centre, Library Avenue, Bailrigg, Lancaster LA1 4AP (United Kingdom); Lofts, Stephen [Centre for Ecology and Hydrology, Lancaster Environment Centre, Library Avenue, Bailrigg, Lancaster LA1 4AP (United Kingdom); Ormerod, Stephen J. [Catchment Research Group, Cardiff School of Biosciences, Cardiff University, Cardiff CF10 3US (United Kingdom); Clements, William H. [Department of Fish, Wildlife, and Conservation Biology, Colorado State University, Fort Collins, CO 80523 (United States); Blust, Ronny [Ecophysiology, Biochemistry and Toxicology Group, Department of Biology, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp (Belgium)

    2010-10-01

    Understanding metal and proton toxicity under field conditions requires consideration of the complex nature of chemicals in mixtures. Here, we demonstrate a novel method that relates streamwater concentrations of cationic metallic species and protons to a field ecological index of biodiversity. The model WHAM-F{sub TOX} postulates that cation binding sites of aquatic macroinvertebrates can be represented by the functional groups of natural organic matter (humic acid), as described by the Windermere Humic Aqueous Model (WHAM6), and supporting field evidence is presented. We define a toxicity function (F{sub TOX}) by summing the products: (amount of invertebrate-bound cation) x (cation-specific toxicity coefficient, {alpha}{sub i}). Species richness data for Ephemeroptera, Plecoptera and Trichoptera (EPT), are then described with a lower threshold of F{sub TOX}, below which all organisms are present and toxic effects are absent, and an upper threshold above which organisms are absent. Between the thresholds the number of species declines linearly with F{sub TOX}. We parameterised the model with chemistry and EPT data for low-order streamwaters affected by acid deposition and/or abandoned mines, representing a total of 412 sites across three continents. The fitting made use of quantile regression, to take into account reduced species richness caused by (unknown) factors other than cation toxicity. Parameters were derived for the four most common or abundant cations, with values of {alpha}{sub i} following the sequence (increasing toxicity) H{sup +} < Al < Zn < Cu. For waters affected mainly by H{sup +} and Al, F{sub TOX} shows a steady decline with increasing pH, crossing the lower threshold near to pH 7. Competition effects among cations mean that toxicity due to Cu and Zn is rare at lower pH values, and occurs mostly between pH 6 and 8.

  1. Chemical Species, Micromorphology, and XRD Fingerprint Analysis of Tibetan Medicine Zuotai Containing Mercury.

    Science.gov (United States)

    Li, Cen; Yang, Hongxia; Du, Yuzhi; Xiao, Yuancan; Zhandui; Sanglao; Wang, Zhang; Ladan, Duojie; Bi, Hongtao; Wei, Lixin

    2016-01-01

    Zuotai ( gTso thal ) is one of the famous drugs containing mercury in Tibetan medicine. However, little is known about the chemical substance basis of its pharmacodynamics and the intrinsic link of different samples sources so far. Given this, energy dispersive spectrometry of X-ray (EDX), scanning electron microscopy (SEM), atomic force microscopy (AFM), and powder X-ray diffraction (XRD) were used to assay the elements, micromorphology, and phase composition of nine Zuotai samples from different regions, respectively; the XRD fingerprint features of Zuotai were analyzed by multivariate statistical analysis. EDX result shows that Zuotai contains Hg, S, O, Fe, Al, Cu, and other elements. SEM and AFM observations suggest that Zuotai is a kind of ancient nanodrug. Its particles are mainly in the range of 100-800 nm, which commonly further aggregate into 1-30  μ m loosely amorphous particles. XRD test shows that β -HgS, S 8 , and α -HgS are its main phase compositions. XRD fingerprint analysis indicates that the similarity degrees of nine samples are very high, and the results of multivariate statistical analysis are broadly consistent with sample sources. The present research has revealed the physicochemical characteristics of Zuotai , and it would play a positive role in interpreting this mysterious Tibetan drug.

  2. Chemical Composition, Larvicidal and Cytotoxic Activities of the Essential Oils from two Bauhinia Species

    Directory of Open Access Journals (Sweden)

    Leôncio M. de Sousa

    2016-05-01

    Full Text Available The essential oils obtained by hydrodistilation from leaves of Bauhinia pulchella Benth. and Bauhinia ungulata L. were analysed by GC-FID and GC-MS. The major components of B. pulchella essential oil were identified as a -pinene (23.9%, caryophyllene oxide (22.4% and b -pinene (12.2%, while in the B. ungulata essential oil were caryophyllene oxide (23.0%, (E-caryophyllene (14.5% and a -copaene (7.2%. The essential oils were subsequently evaluated for their larvicidal and cytotoxic activities. Larval bioassay against Aedes aegypti of B. pulchella and B. ungulata essential oils showed LC 50 values of 105.9 ± 1.5 and 75.1 ± 2.8 m g/mL, respectively. The essential oils were evaluated against four human cancer cells lines: HL-60 (pro-myelocytic leukemia, MCF-7 (breast adenocarcinoma, NCI-H292 (lung carcinoma and HEP-2 ( cervical adenocarcinoma, showing IC 50 values in the range of 9.9 to 53.1 m g/mL. This is the first report on chemical composition of essential from leaves of B. pulchella and on larvicidal and cytotoxic activities of the essential oils.

  3. Chemical Composition and Biological Activities of the Essential Oils from Three Melaleuca Species Grown in Tunisia

    Directory of Open Access Journals (Sweden)

    Ismail Amri

    2012-12-01

    Full Text Available The chemical composition of the essential oils of Melaleuca armillaris Sm., Melaleuca styphelioides Sm. and Melaleuca acuminata F. Muell., collected in Tunisia, was studied by means of GC and GC-MS analysis. In all, 46 compounds were identified, 38 for M. armillaris, 20 for M. acuminata and eight for M. styphelioides, respectively. The presence of a sesquiterpenic fraction (52.2% characterized the oil from M. armillaris; M. sthypheliodes oil was rich in methyl eugenol, a phenolic compound (91.1%, while M. acuminata oil is mainly constituted by oxygenated monoterpenoids (95.6%. The essential oils were evaluated for their in vitro potentially phytotoxic activity against germination and initial radicle growth of Raphanus sativus L., Lepidium sativum L., Sinapis arvensis L., Triticum durum L. and Phalaris canariensis L. seeds. The radicle elongation of five seeds was inhibited at the highest doses tested, while germination of all seeds was not affected. Moreover, the essential oils showed low antimicrobial activity against eight selected microorganisms.

  4. Chemical composition and biological activities of the essential oils from three Melaleuca species grown in Tunisia.

    Science.gov (United States)

    Amri, Ismail; Mancini, Emilia; De Martino, Laura; Marandino, Aurelio; Lamia, Hamrouni; Mohsen, Hanana; Bassem, Jamoussi; Scognamiglio, Mariarosa; Reverchon, Ernesto; De Feo, Vincenzo

    2012-12-05

    The chemical composition of the essential oils of Melaleuca armillaris Sm., Melaleuca styphelioides Sm. and Melaleuca acuminata F. Muell., collected in Tunisia, was studied by means of GC and GC-MS analysis. In all, 46 compounds were identified, 38 for M. armillaris, 20 for M. acuminata and eight for M. styphelioides, respectively. The presence of a sesquiterpenic fraction (52.2%) characterized the oil from M. armillaris; M. sthypheliodes oil was rich in methyl eugenol, a phenolic compound (91.1%), while M. acuminata oil is mainly constituted by oxygenated monoterpenoids (95.6%). The essential oils were evaluated for their in vitro potentially phytotoxic activity against germination and initial radicle growth of Raphanus sativus L., Lepidium sativum L., Sinapis arvensis L., Triticum durum L. and Phalaris canariensis L. seeds. The radicle elongation of five seeds was inhibited at the highest doses tested, while germination of all seeds was not affected. Moreover, the essential oils showed low antimicrobial activity against eight selected microorganisms.

  5. Evolution of 222 Rn and chemical species related with eruptive processes of the Popocatepetl volcano

    International Nuclear Information System (INIS)

    Aranda Z, P.

    1998-01-01

    The study of the water quality for human consumption has always been great importance, considering the factors that can affect water quality as aquifers recharge and underground permeability. In this work, the behavior of three water springs related with the Popocatepetl volcano were studied within April 1997 and March 1998. The spring in Paso de Cortes in the municipality of Amecameca, State of Mexico, and the springs of Atlimeyaya and Axocopan in Atlixco, State of Puebla; the water of these last two springs is used for human consumption. The content of radon in water was determined by means of liquid scintillation, and a concentration of 1.22 Bq/l was found in the spring of Atlimeyaya, which represents 2 % of the maximum permissible level established by ICRP. A significant increase was observed in the Paso de Cortes spring in the month of July 1997. The content of radium, was determined by means of gamma spectrophotometry and small quantities of this element ( 2+ , Mg 2+ , K + , Na + , H C O 3 - , Cl - , S O 4 - 2 , Li, B, Sc, Ti, V, Rb, Sr and Ba, primarily, which did not show any significant variation with the change of seasons. No important variations in the concentration of radon, radium or for other volcanic activity related species were found in the entire study. (Author)

  6. Radioisotope ratios in characterizing the movement of different physical and chemical species through natural soils

    International Nuclear Information System (INIS)

    Robertson, D.E.; Perkins, R.W.

    1975-01-01

    Physicochemical characterization studies of reactor effluent water radionuclides at the Hanford N-Reactor are providing important information describing the mobility of radionuclides in freshwater environments. At N-Reactor, cooling water containing a wide spectrum of radionuclides in various physicochemical forms is discharged to a seepage trench located near the reactor. The effluent water migrates through a soil bank between the trench and the Columbia River, and a portion of the water emerges as seepage springs along the bank of the Columbia River near the reactor. The mobility of effluent water radionuclides during transport through the soil is greatly dependent upon the physicochemical forms of the radionuclides. Radionuclides in particulate and cationic forms are nearly quantitatively retained in the soil bank by sorption onto mineral phases; whereas, radionuclides in anionic and soluble nonionic forms are relatively mobile and are retained by the soil to a much lesser degree. Several radionuclides such as 60 Co, 103-106 Ru and 122-124-125 Sb are present in reactor effluent water partitioned among particulate, cationic, anionic and non-ionic species. However, as these radionuclides migrate through the woil bank their particulate and cationic forms are retained, and predominantly anionic and nonionic forms emerged in the seepage springs. Studies of the behavior of these radionuclides are providing data for assessing present rad-waste treatment processes and in improving future processes for reducing environmental releases of radionuclides from nuclear installations. (author)

  7. In vitro antiplasmodial activity, cytotoxicity and chemical profiles of sponge species of Cuban coasts.

    Science.gov (United States)

    Mendiola, Judith; Regalado, Erik L; Díaz-García, Alexis; Thomas, Olivier P; Fernández-Calienes, Aymé; Rodríguez, Hermis; Laguna, Abilio; Valdés, Olga

    2014-01-01

    Aqueous and organic fractions from the crude extracts of 17 sponge species collected at Boca de Calderas, Havana, Cuba were analysed. The organic fractions of Mycale laxissima, Clathria echinata and Agelas cerebrum exhibited values of concentrations causing 50% inhibition of in vitro growth of Plasmodium berghei (IC50) of 42.3 ± 5.1, 52 ± 9.7 and 60.3 ± 10.6 μg/mL, respectively, while their selectivity indexes for fibroblast cell lines were 9.45, 4.24 and 8.7, correspondingly. These fractions reduced parasitemia of infected Balb/c mice as well. Selective cytotoxicity indexes against tumour HeLa cells focused an interest on the aqueous fraction of M. laxissima (>7.12) and organic fractions of Polymastia nigra (5.95), A. cerebrum (5.48) and Niphates erecta (>4.2). Triterpenoids/steroids and alkaloids detected in the organic fractions of M. laxissima, C. echinata and A. cerebrum should be isolated for future investigation.

  8. Comparative study of the chemical composition of essential oils of five Tagetes species collected in Venezuela.

    Science.gov (United States)

    Armas, Kaylin; Rojas, Janne; Rojas, Luis; Morales, Antonio

    2012-09-01

    The leaves and inflorescences of five species of Tagetes, family Asteraceae, were collected from different locations in Mérida state, Venezuela, and their essential oils analyzed by GC and GC/MS. Several differences were observed in the composition of these oils, mainly regarding the major components, which for T. caracasana were trans-ocimenone (64.3%) and cis-tagetone (13.7%), and for T. erecta, piperitone (35.9%) and terpinolene (22.2%). High amounts of trans-anethole (87.5%) and estragole (10.7%) were observed in T. filifolia, while T. subulata essential oil contained terpinolene (26.0%), piperitenone (13.1%) and limonene (10.8%). For T. patula, two different oil samples were analyzed, leaves (TPL) and inflorescences (TPI). The TPL oil showed terpinolene (20.9%) and piperitenone (14.0%) as main components, while the TPI sample was composed mainly of beta-caryophyllene (23.7%), terpinolene (15.6%) and cis-beta-ocimene (15.5%).

  9. Synthesis of Formamide and Related Organic Species in the Interstellar Medium via Chemical Dynamics Simulations

    Science.gov (United States)

    Spezia, Riccardo; Jeanvoine, Yannick; Hase, William L.; Song, Kihyung; Largo, Antonio

    2016-08-01

    We show, by means of direct dynamics simulations, how it is possible to define possible reactants and mechanisms leading to the formation of formamide in the interstellar medium. In particular, different ion-molecule reactions in the gas phase were considered: NH3OH+, NH2OH{}2+, H2COH+, and NH4 + for the ions and NH2OH, H2CO, and NH3 for the partner neutrals. These calculations were combined with high level ab initio calculations to investigate possible further evolution of the products observed. In particular, for formamide, we propose that the NH2OH{}2+ + H2CO reaction can produce an isomer, NH2OCH{}2+, that, after dissociative recombination, can produce neutral formamide, which was observed in space. The direct dynamics do not pre-impose any reaction pathways and in other reactions, we did not observe the formation of formamide or any possible precursor. On the other hand, we obtained other interesting reactions, like the formation of NH2CH{}2+. Finally, some radiative association processes are proposed. All of the results obtained are discussed in light of the species observed in radioastronomy.

  10. Influence of chemical form, feeding regimen, and animal species on the gastrointestinal absorption of plutonium

    International Nuclear Information System (INIS)

    Bhattacharyya, M.H.; Larsen, R.P.; Cohen, N.; Ralston, L.G.; Oldham, R.D.; Moretti, E.S.; Ayres, L.

    1985-01-01

    We evaluated the effect of chemical form and feeding regimen on the gastrointestinal (GI) absorption of plutonium in adult mice at plutonium concentrations relevant to the establishment of drinking water standards. Mean fractional GI absorption values in fasted adult mice were: Pu(VI) bicarbonate, 15 x 10 -4 ; Pu(IV) bicarbonate, 20 x 10 -4 ; Pu(IV) nitrate (pH2), 17 x 10 -4 ; Pu(IV) citrate, 24 x 10 -4 ; and Pu(IV) polymer, 3 x 10 -4 . Values in fed adult mice were: Pu(VI) bicarbonate, 1.4 x 10 -4 ; Pu(IV) polymer, 0.3 x 10 -4 . Pu(VI) is the oxidation state in chlorinated drinking waters and Pu(IV) is the oxidation state in many untreated natural waters. To assess the validity of extrapolating data from mice to humans, we also determined the GI absorption of Pu(VI) bicarbonate in adult baboons with a dual-isotope method that does not require animal sacrifice. Fractional GI absorption values obtained by this method were 23 +- 10 x 10 -4 for fasted baboons (n=5) and 1.4 +- 0.9 x 10 -4 for fed baboons (n=3). We have so far validated this method in one baboon and are currently completing validation in two additional animals. At low plutonium concentrations, plutonium oxidation state [Pu(VI) vs Pu(IV)] and administration medium (bicarbonate vs nitrate vs citrate) had little effect on the GI absorption of plutonium in mice. Formation of Pu(IV) polymers and animal feeding decreased the GI absorption of plutonium 5- to 10-fold. The GI absorption of Pu(VI) bicarbonate in both fed and fasted adult baboons appeared to be the same as in fed and fasted adult mice, respectively. 17 refs., 2 tabs

  11. Near infra-red chemical species tomography of sprays of volatile hydrocarbons

    Energy Technology Data Exchange (ETDEWEB)

    Hindle, F.P.; Carey, S.J.; Ozanyan, K.B.; McCann, H. [Dept. of Electrical Engineering and Electronics, UMIST, Manchester (United Kingdom); Winterbone, D.E.; Clough, E. [Dept. of Mechanical, Aerospace and Mfg. Engineering, UMIST, Manchester (United Kingdom)

    2002-08-01

    We report an All-Opto-Electronic tomography system that is sensitive to hydrocarbon vapour distribution, or liquid spray distribution, with temporal resolution of over 3000 frames per second. A tomography system comprising 32 channels has been built and tested. For chemical sensitivity to saturated hydrocarbons, we exploit the principle of Near Infra-Red (NIR) absorption at 1700 nm relative to a reference wavelength, using laser diode sources whose technology is based on that of the communications industry. Images are obtained from a laboratory set-up incorporating both gaseous injection and a liquid Gasoline Direct Injection (GDI) system. The performance of a prototype system on a running GDI engine is reported. The difficulty in performing concentration measurements of the gaseous fuel within the liquid spray region is shown, and means to improve this performance are discussed. However, it has been found possible to image the liquid spray cone using attenuation of the reference beam. These images correlate well with other techniques [1]. (orig.) [German] Wir berichten ueber ein optoelektronisches Tomographiesystem zur Bestimmung der Verteilung von Kohlenwasserstoffdaempfen oder von Spraypartikeln, das eine hohe zeitliche Aufloesung von 3000 Aufnahmen pro Sekunde liefert. Ein System mit 32 Kanaelen wurde gebaut und getestet. Um Empfindichkeit auf gesaettigte Kohlenwasserstoffdaempfe zu erzielen, wurde die Absorption im Nahen Infrarot (NIR) bei 1700 nm, bezogen auf die bei einer Referenzwellen-laenge, genutzt. Laserdioden, deren Technologien auch in der Kommunikationstechnik Verwendung finden, kamen zum Einsatz. Von einem Laboraufbau wurden Bilder aufgenommen sowohl bei Injektion von Gas als auch bei Direkteinspritzung fluessigen Brennstoffs (GDI). Wir berichten ueber die Ergebnisse mit dem Prototyp-Messsystem an einem GDI-Motor. Es werden die Schwierigkeiten gezeigt, Messungen der Gaskonzentration innerhalb eines Spraypartikelbereichs durchzufuehren, und

  12. Glacier mass balance reconstruction by sublimation induced enrichment of chemical species on Cerro Tapado (Chilean Andes

    Directory of Open Access Journals (Sweden)

    P. Ginot

    2006-01-01

    Full Text Available A 36 m long ice core down to bedrock from the Cerro Tapado glacier (5536 m a.s.l, 30°08' S, 69°55' W was analyzed to reconstruct past climatic conditions for Northern Chile. Because of the marked seasonality in the precipitation (short wet winter and extended dry summer periods in this region, major snow ablation and related post-depositional processes occur on the glacier surface during summer periods. They include predominantly sublimation and dry deposition. Assuming that, like measured during the field campaign, the enrichment of chloride was always related to sublimation, the chemical record along the ice core may be applied to reconstruct the history of such secondary processes linked to the past climatic conditions over northern Chile. For the time period 1962–1999, a mean annual net accumulation of 316 mm water equivalent (weq and 327 mm weq loss by sublimation was deduced by this method. This corresponds to an initial total annual accumulation of 539 mm weq. The annual variability of the accumulation and sublimation is related with the Southern Oscillation Index (SOI: higher net-accumulation during El-Niño years and more sublimation during La Niña years. The deepest part of the ice record shows a time discontinuity; with an ice body deposited under different climatic conditions: 290 mm higher precipitation but with reduced seasonal distribution (+470 mm in winter and –180 mm in summer and –3°C lower mean annual temperature. Unfortunately, its age is unknown. The comparison with regional proxy data however let us conclude that the glacier buildup did most likely occur after the dry mid-Holocene.

  13. Practical use of chemical probes for reactive oxygen species produced in biological systems by {gamma}-irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Min Hee; Moon, Yu Ran; Chung, Byung Yeoup; Kim, Jae-Sung [Radiation Research Division for Bio-technology, Korea Atomic Energy Research Institute, 1266 Sinjeong-dong, Jeongeup-si, Jeollabuk-do 580-185 (Korea, Republic of); Lee, Kang-Soo [Crop Production and Technology Major, Chonbuk National University, Jeonju 561-756 (Korea, Republic of); Cho, Jae-Young [Bio-environmental Science Major, Chonbuk National University, Jeonju 561-756 (Korea, Republic of); Kim, Jin-Hong [Radiation Research Division for Bio-technology, Korea Atomic Energy Research Institute, 1266 Sinjeong-dong, Jeongeup-si, Jeollabuk-do 580-185 (Korea, Republic of)], E-mail: jhongkim@kaeri.re.kr

    2009-05-15

    Application of chemical probes, for detection of reactive oxygen species (ROS), was tested during {gamma}-irradiation. The ethanol/{alpha}-(4-pyridyl-1-oxide)-N-tert-butylnitrone (4-POBN) and 3,3'-diaminobenzidine (DAB) were structurally stable enough to detect {sup {center_dot}}OH and H{sub 2}O{sub 2}, increasingly generated by {gamma}-irradiation up to 1000 Gy. Interestingly, the production rate of H{sub 2}O{sub 2}, but not {sup {center_dot}}OH, during {gamma}-irradiation, was significantly different between in vitro systems of lettuce and spinach. These results suggest that 4-POBN and DAB could be utilized as a semi-quantitative probe to quantify {sup {center_dot}}OH and H{sub 2}O{sub 2}, produced by {gamma}-irradiation up to 1000 Gy.

  14. Simultaneous Temperature and Velocity Diagnostic for Reacting Flows, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — A diagnostic technique is proposed for measuring temperature and velocity simultaneously in a high temperature reacting flow for aiding research in propulsion. The...

  15. Sequential chemical treatment of radium species in TENORM waste sludge produced from oil and natural gas production

    International Nuclear Information System (INIS)

    El Afifi, E.M.; Awwad, N.S.; Hilal, M.A.

    2009-01-01

    This paper is dedicated to the treatment of sludge occurring in frame of the Egyptian produced from oil and gas production. The activity levels of three radium isotopes: Ra-226 (of U-series), Ra-228 and Ra-224 (of Th-series) in the solid TENORM waste (sludge) were first evaluated and followed by a sequential treatment for all radium species (fractions) presented in TENORM. The sequential treatment was carried out based on two approaches 'A' and 'B' using different chemical solutions. The results obtained indicate that the activity levels of all radium isotopes (Ra-226, Ra-228 and Ra-224) of the environmental interest in the TENORM waste sludge were elevated with regard to exemption levels established by IAEA [International Atomic Energy Agency (IAEA), International basic safety standards for the protection against ionizing radiation and for the safety of radiation sources. GOV/2715/Vienna, 1994]. Each approach of the sequential treatment was performed through four steps using different chemical solutions to reduce the activity concentration of radium in a large extent. Most of the leached radium was found as an oxidizable Ra species. The actual removal % leached using approach B was relatively efficient compared to A. It is observed that the actual removal percentages (%) of Ra-226, Ra-228 and Ra-224 using approach A are 78 ± 2.8, 64.8 ± 4.1 and 76.4 ± 5.2%, respectively. Whereas in approach A, the overall removal % of Ra-226, Ra-228 and Ra-228 was increased to ∼91 ± 3.5, 87 ± 4.1 and 90 ± 6.2%, respectively

  16. Chemical Diversity and Biological Activity of the Volatiles of Five Artemisia Species from Far East Russia

    Directory of Open Access Journals (Sweden)

    Gulmira Özek

    2014-05-01

    Full Text Available Artemisia argyi , A. feddei, A. gmelinii, A. manshurica, and A. olgensis (Asteraceae were collected in Far East Russia. Oils were hydrodistilled and simultaneously analyzed by GC-FID and GC/MS. Main constituents were found as follows in Artemisia oils: selin-11-en-4 a -ol (18.0%, 1,8-cineole (14.2.0%, artemisia alcohol (12.9%, borneol (9.7% in A. argyi; camphor (31.2%, 1,8-cineole (17.6%, a -thujone (5.7% in A. feddei; longiverbenone (12.0%, isopinocamphone (8.9%, 1,8-cineole (6.7%, camphor (5.8%, trans-p-menth-2-en-1-ol (5.3% in A. gmelinii; germacrene D (11.2%, rosifoliol (10.1%, caryophyllene oxide (6.8%, eudesma-4(15,7-dien-1 b -ol (5.6% in A. manshurica; eudesma-4(15,7-dien-1 b -ol (6.9%, caryophyllene oxide (5.6%, guaia-6,10(14-dien-4 b -ol (5.1% and hexadecanoic acid (5.0% in A. olgensis. Oils were subsequently submitted for antifungal and antimosquito evaluations. Artemisia species oils showed biting deterrent effects in Aedes aegypti and Artemisia gmelinii oil with the most active biting deterrence index values of 0.82 ± 0.1 at 10 m g/mL. Larval bioassay of A. gmelinii and A. olgensis oils showed higher larvicidal activity against Ae. aegypti larvae with LD50 values of 83.8 (72.6 – 95.7 ppm and 91.0 (73.8 – 114.5 ppm, respectively. Antifungal activity was evaluated against the strawberry anthracnose-causing fungal plant pathogens Colletotrichum acutatum, C. fragariae and C. gloeosporioides using direct overlay bioautography assay and all showed non-selective weak antifungal activity. Antioxidant evaluations of the oils were performed by using b -carotene bleaching, Trolox equivalent and DPPH tests. The tested Artemisia oils demonstrated moderate antioxidant activity.

  17. Essential Oils from Leaves of Medicinal Plants of Brazilian Flora: Chemical Composition and Activity against Candida Species

    Directory of Open Access Journals (Sweden)

    Maria da Conceição Mendes Ferreira da Costa

    2017-05-01

    Full Text Available Background: The biotechnological potential of medicinal plants from Brazilian Caatinga and the Atlantic Forest has not been extensively studied. Thus, screening programs are important in prospecting for compounds for developing new drugs. The purpose of this study was to determine the chemical composition and to evaluate the anti-Candida activity of essential oils from leaves of Hymenaea courbaril var. courbaril, Myroxylon peruiferum, and Vismia guianensis. Methods: The oils were extracted through hydrodistillation and their chemical compositions were analyzed by gas chromatography coupled with mass spectrometry. Antifungal activity against C. albicans, C. tropicalis, C. parapsilosis, C. glabrata, and C. krusei was evaluated by determining the minimal inhibitory (MIC and fungicidal (MFC concentrations. Results: The major compounds of the oils were caryophyllene oxide and trans-caryophyllene for H. courbaril; spathulenol, α-pinene, and caryophyllene oxide for M. peruiferum; and caryophyllene oxide and humulene epoxide II for V. guianensis oil. The oils showed antifungal activity against all the strains tested, and the MIC values ranged between 0.625 and 1.25 μL/mL and MFC from 0.625 to 2.5 μL/mL. Conclusion: The essential oils from the species studied have the potential to be evaluated as clinical applications in the treatment of candidiasis.

  18. Influence of the mineralogical composition of cement in the diffusion of chemical species

    International Nuclear Information System (INIS)

    Galicia A, E.

    2015-01-01

    , color and others. Portland cements commonly used in the construction industry, they are based primarily on the mineral phases of limestone and silica. In conventional cement admixtures the chemical reactivity depends on the ratio of tricalcium and dicalcium silicate (C 3 S/C 2 S), the tricalcium aluminate (C 3 A) influences in the setting time and tetra calcium ferro aluminate (C 4 AF) gives a different color to the cement. In this research the mineralogical composition of two commercial cements is studied and its influence on the phenomenon of radionuclides retention. For this particular concrete discs were manufactured with water, sand and two commercial cements: Tolteca Extra CPC 30-RRS and Cruz Azul CPC Type II 30-R. The solid observation techniques used for analysis of the cement paste and concrete they are: X-ray Diffraction and Scanning Electron Microscopy, as well as the nuclear analytic techniques of Moessbauer and X-ray Fluorescence. (Author)

  19. Determination of thephysico-chemical 131I species in the exhausts and stack effluent of a PWR power plant

    International Nuclear Information System (INIS)

    Deuber, H.; Wilhelm, J.G.

    1979-01-01

    To quantify the credit that can be granted in the assessment of the 131 I ingestion doses and the improvement that can be achieved in the ventilation systems if differences of the physico-chemical 131 I species with respect to the environmental impact are taken into account, the fractions of the 131 I species were determined in the stack effluent and in various exhausts of a 1300 MW/sub e/ PWR power plant during a period of 3 months. Based on these measurements, calculations for different cases of filtration of the main exhausts for iodine were carried out. The average fractions of elemental and organic 131 I were about 70 and 30% respectively in the stack effluent during the time indicated. Elem. 131 I orginated mainly from the hoods in which samples of the primary coolant are taken and processed. Org. 131 I was mainly contributed by the equipment compartments. If the hood exhaust had been filtered, as was the case with the equipment compartment exhaust, the fractions of elem. and org. 131 I would have been on the order of 50% each and the calculated 131 I ingestion doses would have been a factor of 3 lower

  20. Auto-digital gain balancing: a new detection scheme for high-speed chemical species tomography of minor constituents

    International Nuclear Information System (INIS)

    Pal, Sandip; McCann, Hugh

    2011-01-01

    In many dynamic gas-phase reaction processes, there is great interest to measure the distribution of minor constituents, i.e. −3 by volume (1000 ppm). One such case is the after-treatment of automotive gasoline engine exhaust by catalytic conversion, where a characteristic challenge is to image the distribution of 10 ppm (average) of carbon monoxide (CO) at 1000 frames per second across a 50 mm diameter exhaust pipe; this particular problem has been pursued as a case study. In this paper, we present a novel electronic scheme that achieves the required measurement of around 10 −3 absorption with 10 −4 precision at kHz bandwidth. This was not previously achievable with any known technology. We call the new scheme Auto-Digital Gain Balancing. It is amenable to replication for many simultaneous measurement channels, and it permits simultaneous measurement of multiple species, in some circumstances. Experimental demonstrations are presented in the near-infrared. In single scans of a tunable diode laser, measurements of both CO and CO 2 have been made with 20 dB signal-to-noise ratio at peak absorption. This work paves the way for chemical species tomography of minor constituents in many dynamic gas-phase systems

  1. Mercury from combustion sources: a review of the chemical species emitted and their transport in the atmosphere

    International Nuclear Information System (INIS)

    Carpi, A.

    1997-01-01

    Different species of mercury have different physical/chemical properties and thus behave quite differentially in air pollution control equipment and in the atmosphere. In general, emission of mercury from coal combustion sources are approximately 20-50% elemental mercury (Hg 0 ) and 50-80% divalent mercury (Hg(II)), which may be predominantly HgCl 2 . Emissions of mercury from waste incinerators are approximately 10-20% Hg 0 and 75-85% Hg(II). The partitioning of mercury in flue gas between the elemental and divalent forms may be dependent on the concentration of particulate carbon, HCl and other pollutants in the stack emissions. The emission of mercury from combustion facilities depends on the species in the exhaust stream and the type of air pollution control equipment used at the source. Air pollution control equipment for mercury removal at combustion facilities includes activated carbon injection, sodium sulfide injection and wet lime/limestone flue gas desulfurization. White Hg(II) is water-soluble and may be removed form the atmosphere by wet and dry deposition close to the combustion sources, the combination of a high vapor pressure and low water-solubility facilitate the long-range transport of Hg 0 in the atmosphere. Background mercury in the atmosphere is predominantly Hg 0 . Elemental mercury is eventually removed from the atmosphere by dry deposition onto surfaces and by wet deposition after oxidation to water-soluble, divalent mercury. 62 refs., 2 figs., 1 tab

  2. Diffusion approximations to the chemical master equation only have a consistent stochastic thermodynamics at chemical equilibrium.

    Science.gov (United States)

    Horowitz, Jordan M

    2015-07-28

    The stochastic thermodynamics of a dilute, well-stirred mixture of chemically reacting species is built on the stochastic trajectories of reaction events obtained from the chemical master equation. However, when the molecular populations are large, the discrete chemical master equation can be approximated with a continuous diffusion process, like the chemical Langevin equation or low noise approximation. In this paper, we investigate to what extent these diffusion approximations inherit the stochastic thermodynamics of the chemical master equation. We find that a stochastic-thermodynamic description is only valid at a detailed-balanced, equilibrium steady state. Away from equilibrium, where there is no consistent stochastic thermodynamics, we show that one can still use the diffusive solutions to approximate the underlying thermodynamics of the chemical master equation.

  3. Gene expression responses of HeLa cells to chemical species generated by an atmospheric plasma flow

    International Nuclear Information System (INIS)

    Yokoyama, Mayo; Johkura, Kohei; Sato, Takehiko

    2014-01-01

    Highlights: • Response of HeLa cells to a plasma-irradiated medium was revealed by DNA microarray. • Gene expression pattern was basically different from that in a H 2 O 2 -added medium. • Prominently up-/down-regulated genes were partly shared by the two media. • Gene ontology analysis showed both similar and different responses in the two media. • Candidate genes involved in response to ROS were detected in each medium. - Abstract: Plasma irradiation generates many factors able to affect the cellular condition, and this feature has been studied for its application in the field of medicine. We previously reported that hydrogen peroxide (H 2 O 2 ) was the major cause of HeLa cell death among the chemical species generated by high level irradiation of a culture medium by atmospheric plasma. To assess the effect of plasma-induced factors on the response of live cells, HeLa cells were exposed to a medium irradiated by a non-lethal plasma flow level, and their gene expression was broadly analyzed by DNA microarray in comparison with that in a corresponding concentration of 51 μM H 2 O 2 . As a result, though the cell viability was sufficiently maintained at more than 90% in both cases, the plasma-medium had a greater impact on it than the H 2 O 2 -medium. Hierarchical clustering analysis revealed fundamentally different cellular responses between these two media. A larger population of genes was upregulated in the plasma-medium, whereas genes were downregulated in the H 2 O 2 -medium. However, a part of the genes that showed prominent differential expression was shared by them, including an immediate early gene ID2. In gene ontology analysis of upregulated genes, the plasma-medium showed more diverse ontologies than the H 2 O 2 -medium, whereas ontologies such as “response to stimulus” were common, and several genes corresponded to “response to reactive oxygen species.” Genes of AP-1 proteins, e.g., JUN and FOS, were detected and notably elevated in

  4. An advanced method of contributing emissions to short-lived chemical species (OH and HO2: the TAGGING 1.1 submodel based on the Modular Earth Submodel System (MESSy 2.53

    Directory of Open Access Journals (Sweden)

    V. S. Rieger

    2018-06-01

    Full Text Available To mitigate the human impact on climate change, it is essential to determine the contribution of emissions to the concentration of trace gases. In particular, the source attribution of short-lived species such as OH and HO2 is important as they play a crucial role for atmospheric chemistry. This study presents an advanced version of a tagging method for OH and HO2 (HOx which attributes HOx concentrations to emissions. While the former version (V1.0 only considered 12 reactions in the troposphere, the new version (V1.1, presented here, takes 19 reactions in the troposphere into account. For the first time, the main chemical reactions for the HOx chemistry in the stratosphere are also regarded (in total 27 reactions. To fully take into account the main HO2 source by the reaction of H and O2, the tagging of the H radical is introduced. In order to ensure the steady-state assumption, we introduce rest terms which balance the deviation of HOx production and loss. This closes the budget between the sum of all contributions and the total concentration. The contributions to OH and HO2 obtained by the advanced tagging method V1.1 deviate from V1.0 in certain source categories. For OH, major changes are found in the categories biomass burning, biogenic emissions and methane decomposition. For HO2, the contributions differ strongly in the categories biogenic emissions and methane decomposition. As HOx reacts with ozone (O3, carbon monoxide (CO, reactive nitrogen compounds (NOy, non-methane hydrocarbons (NMHCs and peroxyacyl nitrates (PAN, the contributions to these species are also modified by the advanced HOx tagging method V1.1. The contributions to NOy, NMHC and PAN show only little change, whereas O3 from biogenic emissions and methane decomposition increases in the tropical troposphere. Variations for CO from biogenic emissions and biomass burning are only found in the Southern Hemisphere.

  5. Heat Effect of the Protonation of Glycine and the Enthalpies of Resolvation of Participating Chemical Species in Water-Dimethylsulfoxide Solvent Mixtures

    Science.gov (United States)

    Isaeva, V. A.; Sharnin, V. A.

    2018-02-01

    Enthalpies of the protonation of glycine in water‒dimethylsulfoxide (DMSO) mixed solvents are determined calorimetrically in the range of DMSO mole fractions of 0.0 to 0.9, at T = 298.15 K and an ionic strength μ = 0.3 (NaClO4). It is established that the protonation of glycine becomes more exothermic with an increasing mole fraction of DMSO, and the enthalpies of resolvation of glycine and glycinium ions in water‒DMSO solvent mixtures are calculated. It is shown that the small changes in the enthalpy of protonation observed at low mole fractions of DMSO are caused by the contributions from the solvation of proton and protonated glycine cancelling each other out. The enthalpy term of the Gibbs energy of the reaction leading to the formation of glycinium ion is estimated along with the enthalpy of resolvation of the reacting species in the water‒DMSO mixed solvent.

  6. Mechanism for Self-Reacted Friction Stir Welding

    Science.gov (United States)

    Venable, Richard; Bucher, Joseph

    2004-01-01

    A mechanism has been designed to apply the loads (the stirring and the resection forces and torques) in self-reacted friction stir welding. This mechanism differs somewhat from mechanisms used in conventional friction stir welding, as described below. The tooling needed to apply the large reaction loads in conventional friction stir welding can be complex. Self-reacted friction stir welding has become popular in the solid-state welding community as a means of reducing the complexity of tooling and to reduce costs. The main problems inherent in self-reacted friction stir welding originate in the high stresses encountered by the pin-and-shoulder assembly that produces the weld. The design of the present mechanism solves the problems. The mechanism includes a redesigned pin-and-shoulder assembly. The welding torque is transmitted into the welding pin by a square pin that fits into a square bushing with set-screws. The opposite or back shoulder is held in place by a Woodruff key and high-strength nut on a threaded shaft. The Woodruff key reacts the torque, while the nut reacts the tensile load on the shaft.

  7. Chemical contamination assessment in mangrove-lined Caribbean coastal systems using the oyster Crassostrea rhizophorae as biomonitor species.

    Science.gov (United States)

    Aguirre-Rubí, Javier R; Luna-Acosta, Andrea; Etxebarría, Nestor; Soto, Manu; Espinoza, Félix; Ahrens, Michael J; Marigómez, Ionan

    2018-05-01

    This paper aims to contribute to the use of mangrove cupped oyster, Crassostrea rhizophorae, as a biomonitor species for chemical contamination assessment in mangrove-lined Caribbean coastal systems. Sampling was carried out in eight localities (three in Nicaragua and five in Colombia) with different types and levels of contamination. Oysters were collected during the rainy and dry seasons of 2012-2013 and the tissue concentrations of metals, polycyclic aromatic hydrocarbons (PAHs), and persistent organic pollutants (POPs) were determined. Low tissue concentrations of metals (except Hg) and PAHs; moderate-to-high tissue concentrations of Hg, hexachlorocyclohexanes (HCHs), and dichlorodiphenyl-trichloroethanes (DDTs); detectable levels of chlorpyrifos, polychlorinated biphenyls (PCBs) (mainly CB28, CB118, CB138 and CB 153) and brominated diphenyl ethers 85 (BDE85); and negligible levels of musks were recorded in Nicaraguan oysters. A distinct profile of POPs was identified in Colombia, where the tissue concentrations of PCBs and synthetic musk fragrances were low to moderate, and Ag, As, Cd, Pb, and PAHs ranged from moderate to extremely high. Overall, the values recorded for HCHs, DDTs and PCBs in Nicaraguan mangrove cupped oysters greatly exceeded the reference values in tissues of C. rhizophorae from the Wider Caribbean Region, whereas only the levels of PCBs were occasionally surpassed in Colombia. Different contaminant profiles were distinguished between oysters from Nicaragua and Colombia in radar plots constructed using the main groups of contaminants (metals, PAHs, musks, PCBs, and organochlorine pesticides (OCPs)). Likewise, integrated pollution indices revealed differences in the levels of contaminants. Moreover, the profiles and levels in oyster tissues also varied with season. Thus, principal component analysis clearly discriminated Nicaraguan and Colombian localities and, especially in Colombia, seasonal trends in chemical contamination and differences

  8. Chemical vapor generation of silver for atomic absorption spectrometry with the multiatomizer: Radiotracer efficiency study and characterization of silver species

    Energy Technology Data Exchange (ETDEWEB)

    Musil, Stanislav [Institute of Analytical Chemistry of the ASCR, v.v.i., Videnska 1083, 142 20 Prague 4 (Czech Republic); Charles University in Prague, Faculty of Science, Dept. of Analytical Chemistry, Albertov 8, 128 43 Prague 2 (Czech Republic); Kratzer, Jan; Vobecky, Miloslav [Institute of Analytical Chemistry of the ASCR, v.v.i., Videnska 1083, 142 20 Prague 4 (Czech Republic); Hovorka, Jan [Charles University in Prague, Faculty of Science, Institute for Environmental Studies, Benatska 2, 128 01 Prague 2 (Czech Republic); Benada, Oldrich [Institute of Microbiology of the ASCR, v.v.i., Videnska 1083, 142 20 Prague 4 (Czech Republic); Matousek, Tomas, E-mail: matousek@biomed.cas.c [Institute of Analytical Chemistry of the ASCR, v.v.i., Videnska 1083, 142 20 Prague 4 (Czech Republic)

    2009-11-15

    Volatile Ag species were generated in flow injection arrangement from nitric acid environment in the presence of surfactants (Triton X-100 and Antifoam B) and permanent Pd deposits as the reaction modifiers. Atomic absorption spectrometry (AAS) with multiple microflame quartz tube atomizer heated to 900 deg. C was used for atomization; evidence was found for thermal mechanism of atomization. Relative and absolute limits of detection (3sigma, 250 mul sample loop) measured under optimized conditions were: 1.4 mug l{sup -1} and 0.35 ng, respectively. The efficiency of chemical vapor generation (CVG) as well as spatial distribution of residual analyte in the apparatus was studied by {sup 111}Ag radioactive indicator (half-life 7.45 days) of high specific activity. It was found out that 23% of analyte was released into the gaseous phase. However, only 8% was found on filters placed at the entrance to the atomizer due to transport losses. About 40% of analyte remained in waste liquid, whereas the rest was found deposited over the CVG system. Presented study follows the hypothesis that the 'volatile' Ag species are actually metallic nanoparticles formed upon reduction in liquid phase and then released with good efficiency to the gaseous phase. Number/charge size distributions of dry aerosol were determined by Scanning Mobility Particle Sizer. Ag was detected in 40-45 nm particles holding 10 times more charge if compared to Boltzmann equilibrium. At the same time, Ag was also present on 150 nm particles, the main size mode of the CVG generator. The increase of Ag in standards was reflected by proportional increase in particle number/charge for 40-45 nm size particles only. Transmission electron microscopy revealed particles of 8 +- 2 nm sampled from the gaseous phase, which were associated in isolated clusters of few to few tens of nanometres. Ag presence in those particles was confirmed by Energy Dispersive X-ray Spectroscopy (EDS) analysis.

  9. Natural background levels and threshold values of chemical species in three large-scale groundwater bodies in Northern Italy

    International Nuclear Information System (INIS)

    Molinari, Antonio; Guadagnini, Laura; Marcaccio, Marco; Guadagnini, Alberto

    2012-01-01

    We analyze natural background levels (NBLs) and threshold values (TVs) of spatially distributed chemical species (NH 4 , B and As) which may be a potential pressure and concern in three large scale alluvial and fluvio-deltaic aquifers at different depths of the Apennines and Po river plains in Emilia–Romagna, Northern Italy. Our results are based on statistical methodologies designed to separate the natural and anthropogenic contributions in monitored concentrations by modeling the empirical distribution of the detected concentration with a mixture of probability density functions. Available chemical observations are taken over a 20 years period and are associated with different depths and cover planar investigation scales of the order of hundreds of kilometers. High concentration values detected for NH 4 and B appear to be related to high natural background levels. Due to interaction with the host rock in different geochemical environments we observed that concentration vary in time and space (including in depth) consistently with the hydrogeochemical features and the occurrence of natural attenuation mechanisms in the analyzed reservoirs. Conversely, estimated As NBLs are not consistent with the conceptual model of the hydrogeochemical behavior of the systems analyzed and experimental evidences of As content in aquifer cores. This is due to the inability of these techniques to incorporate the complex dynamics of the processes associated with the specific hydrogeochemical setting. Statistical analyses performed upon aggregating the concentration data according to different time observation windows allow identifying temporal dynamics of NBLs and TVs of target compounds within the observation time frame. Our results highlight the benefit of a dynamic monitoring process and analysis of well demarcated groundwater bodies to update the associated NBLs as a function of the temporal dependence of natural processes occurring in the subsurface. Monitoring protocols could

  10. Natural background levels and threshold values of chemical species in three large-scale groundwater bodies in Northern Italy

    Energy Technology Data Exchange (ETDEWEB)

    Molinari, Antonio, E-mail: ant.molinari2002@libero.it [Politecnico di Milano, Dipartimento di Ingegneria Idraulica, Ambientale, Infrastrutture Viarie e Rilevamento, Piazza L. Da Vinci, 32-20133 Milano (Italy); Guadagnini, Laura [Politecnico di Milano, Dipartimento di Ingegneria Idraulica, Ambientale, Infrastrutture Viarie e Rilevamento, Piazza L. Da Vinci, 32-20133 Milano (Italy); Marcaccio, Marco [ARPA Emilia-Romagna, Direzione Tecnica, Largo Caduti del Lavoro, 6-40122 Bologna (Italy); Guadagnini, Alberto [Politecnico di Milano, Dipartimento di Ingegneria Idraulica, Ambientale, Infrastrutture Viarie e Rilevamento, Piazza L. Da Vinci, 32-20133 Milano (Italy)

    2012-05-15

    We analyze natural background levels (NBLs) and threshold values (TVs) of spatially distributed chemical species (NH{sub 4}, B and As) which may be a potential pressure and concern in three large scale alluvial and fluvio-deltaic aquifers at different depths of the Apennines and Po river plains in Emilia-Romagna, Northern Italy. Our results are based on statistical methodologies designed to separate the natural and anthropogenic contributions in monitored concentrations by modeling the empirical distribution of the detected concentration with a mixture of probability density functions. Available chemical observations are taken over a 20 years period and are associated with different depths and cover planar investigation scales of the order of hundreds of kilometers. High concentration values detected for NH{sub 4} and B appear to be related to high natural background levels. Due to interaction with the host rock in different geochemical environments we observed that concentration vary in time and space (including in depth) consistently with the hydrogeochemical features and the occurrence of natural attenuation mechanisms in the analyzed reservoirs. Conversely, estimated As NBLs are not consistent with the conceptual model of the hydrogeochemical behavior of the systems analyzed and experimental evidences of As content in aquifer cores. This is due to the inability of these techniques to incorporate the complex dynamics of the processes associated with the specific hydrogeochemical setting. Statistical analyses performed upon aggregating the concentration data according to different time observation windows allow identifying temporal dynamics of NBLs and TVs of target compounds within the observation time frame. Our results highlight the benefit of a dynamic monitoring process and analysis of well demarcated groundwater bodies to update the associated NBLs as a function of the temporal dependence of natural processes occurring in the subsurface. Monitoring

  11. Determining High-Quality Critical Body Residues for Multiple Species and Chemicals by Applying Improved Experimental Design and Data Interpretation Concepts

    DEFF Research Database (Denmark)

    van der Heijden, Stephan A.; Hermens, Joop L. M.; Sinnige, Theo L.

    2015-01-01

    Ecotoxicological effect data are generally expressed as effective concentrations in the external exposure medium and do thus not account for differences in chemical uptake, bioavailability, and metabolism, which can introduce substantial data variation. The Critical Body Residue (CBR) concept......, and by a factor of 2.6 between the three species but for individual chemicals. Accounting for the chemicals internal distribution to different partitioning domains and relating effects to estimated concentrations in the target compartment (i.e., membrane lipids) was expected to but did not decrease the overall...

  12. Chemical composition of 8 eucalyptus species' essential oils and the evaluation of their antibacterial, antifungal and antiviral activities

    Directory of Open Access Journals (Sweden)

    Elaissi Ameur

    2012-06-01

    Full Text Available Abstract Background In 1957, Tunisia introduced 117 species of Eucalyptus; they have been used as fire wood, for the production of mine wood and to fight erosion. Actually, Eucalyptus essential oil is traditionally used to treat respiratory tract disorders such as pharyngitis, bronchitis, and sinusitis. A few investigations were reported on the biological activities of Eucalyptus oils worldwide. In Tunisia, our previous works conducted in 2010 and 2011 had been the first reports to study the antibacterial activities against reference strains. At that time it was not possible to evaluate their antimicrobial activities against clinical bacterial strains and other pathogens such as virus and fungi. Methods The essential oils of eight Eucalyptus species harvested from the Jbel Abderrahman, Korbous (North East Tunisia and Souinet arboreta (North of Tunisia were evaluated for their antimicrobial activities by disc diffusion and microbroth dilution methods against seven bacterial isolates: Haemophilus influenzae, Klebsiella pneumoniae, Pseudomonas aeruginosa, Staphylococcus aureus, Streptococcus agalactiae, Streptococcus pneumoniae and Streptococcus pyogenes. In addition, the bactericidal, fungicidal and the antiviral activities of the tested oils were carried out. Results Twenty five components were identified by GC/FID and GC/MS. These components were used to correlate with the biological activities of the tested oils. The chemical principal component analysis identified three groups, each of them constituted a chemotype. According to the values of zone diameter and percentage of the inhibition (zdi, % I, respectively, four groups and subgroups of bacterial strains and three groups of fungal strains were characterized by their sensitivity levels to Eucalyptus oils. The cytotoxic effect and the antiviral activity varied significantly within Eucalyptus species oils. Conclusions E. odorata showed the strongest activity against S. aureus, H. influenzae

  13. Chemical composition of 8 eucalyptus species' essential oils and the evaluation of their antibacterial, antifungal and antiviral activities

    Science.gov (United States)

    2012-01-01

    Background In 1957, Tunisia introduced 117 species of Eucalyptus; they have been used as fire wood, for the production of mine wood and to fight erosion. Actually, Eucalyptus essential oil is traditionally used to treat respiratory tract disorders such as pharyngitis, bronchitis, and sinusitis. A few investigations were reported on the biological activities of Eucalyptus oils worldwide. In Tunisia, our previous works conducted in 2010 and 2011 had been the first reports to study the antibacterial activities against reference strains. At that time it was not possible to evaluate their antimicrobial activities against clinical bacterial strains and other pathogens such as virus and fungi. Methods The essential oils of eight Eucalyptus species harvested from the Jbel Abderrahman, Korbous (North East Tunisia) and Souinet arboreta (North of Tunisia) were evaluated for their antimicrobial activities by disc diffusion and microbroth dilution methods against seven bacterial isolates: Haemophilus influenzae, Klebsiella pneumoniae, Pseudomonas aeruginosa, Staphylococcus aureus, Streptococcus agalactiae, Streptococcus pneumoniae and Streptococcus pyogenes. In addition, the bactericidal, fungicidal and the antiviral activities of the tested oils were carried out. Results Twenty five components were identified by GC/FID and GC/MS. These components were used to correlate with the biological activities of the tested oils. The chemical principal component analysis identified three groups, each of them constituted a chemotype. According to the values of zone diameter and percentage of the inhibition (zdi, % I, respectively), four groups and subgroups of bacterial strains and three groups of fungal strains were characterized by their sensitivity levels to Eucalyptus oils. The cytotoxic effect and the antiviral activity varied significantly within Eucalyptus species oils. Conclusions E. odorata showed the strongest activity against S. aureus, H. influenzae, S. agalactiae, S. pyogenes

  14. Air corona discharge chemical kinetics

    International Nuclear Information System (INIS)

    Kline, L.E.; Kanter, I.E.

    1984-01-01

    We have theoretically studied the initial chemical processing steps which occur in pulseless, negative, dc corona discharges in flowing air. A rate equation model is used because these discharges consist of a very small ionization zone near the pin with most of the pin-plane gap filled by a drift zone where both the electric field and the electron density are relatively uniform. The primary activated species are N 2 (A),O and O 2 (a 1 Δ). The predicted activated species density due to one discharge is 100 ppm per ms . mA cm 2 assuming E/n=60 Td. In pure, dry air the final product due to these activated species is primarily O 3 . The NO /sub x/ production is about 0.5 ppm per mA. In moist air there is an additional production of about 1.5 ppm per mA of HO /sub x/ species. The predicted ozone formation reactions will be ''intercepted'' when impurities are present in the air. Impurities present at densities below about 0.1% will react primarily with the activated species rather than with electrons. Hence the predicted activated species density provides an estimate of the potential chemical processing performance of the discharge

  15. Sentinel Gap basalt reacted in a temperature gradient

    International Nuclear Information System (INIS)

    Charles, R.W.; Bayhurst, G.K.

    1983-01-01

    Six basalt prisms were reacted in a controlled temperature gradient hydrothermal circulation system for two months. The prisms were centered at 72, 119, 161, 209, 270, and 310 0 C. Total pressure was 1/3 kbar. All prisms showed large weight loss: 5.5% to 14.9%. The matrix micropegmatite and natural nontronitic alteration reacted readily to clays at all temperatures. The first four prisms were coated with a calcium smectite, and the last two prisms were covered with discrete patches of potassium-rich phengite and alkali feldspar. The results indicated that clays may act as adsorbers of various ions

  16. Sentinel Gap basalt reacted in a temperature gradient

    International Nuclear Information System (INIS)

    Charles, R.W.; Bayhurst, G.K.

    1982-01-01

    Six basalt prisms were reacted in a controlled temperature gradient hydrothermal circulation system for two months. The prisms are centered at 72, 119, 161, 209, 270, and 310 0 C. Total pressure is 1/3 kbar. All prisms show large weight loss: 5.5% to 14.9%. The matrix micropegmatite and natural nontronitic alteration readily reacts to clays at all temperatures. The first four prisms are coated with a Ca-smectite while the last two prisms are covered with discrete patches of K rich phengite and alkali feldspar. The clays may act as adsorbers of various ions

  17. Effect of salt species on electrochemical properties of gel-type polymer electrolyte based on chemically crosslinking rubber

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Kab Youl; Jo, Nam Ju [Pusan National Univ., Busan (Korea). Dept. of Polymer Science and Engineering; Chung, Won Sub [Pusan National Univ., Busan (Korea). School of Materials Science and Engineering

    2004-11-30

    In our study, for ion-polymer interaction in gel-type polymer electrolyte (GPE), two kinds of ions were used. GPE systems were composed of Mg or Li salt, organic solvent ({gamma}-BL), and polymer matrix prepared by chemical crosslinking of NBR with poly(ethylene glycol) methylethermethacrylate (PEGMEM) having polar group (--CH{sub 2}--CH{sub 2}--O--) in the side chain of monomer. GPE consisting of Li{sup +} ion had higher ionic conductivity than that of Mg{sup 2+} ion at below 100 wt.% of electrolyte content (1 M salt/{gamma}-BL). On the other hand, GPE consisting of Mg{sup 2+} ion had higher ionic conductivity than that consisting of Li{sup +} ion at over 120 wt.% of electrolyte content (1 M salt/{gamma}-BL). The maximum liquid electrolyte content was 200 wt.% for all GPE systems. And the highest ionic conductivity of 3.3 x 10{sup -2} S cm{sup -1} was achieved for the case of Mg{sup 2+}-GPE with 200 wt.% of liquid electrolyte contents at 20 C. The interaction between ionic species and polymer matrix in GPE was investigated by using Fourier transform infrared spectroscopy (FT-IR). Also, cyclic voltammogram of Mg{sup 2+}-GPE confirmed the electrochemical property of divalent cation with two electron-transfer reactions.

  18. The role of the gas species on the formation of carbon nanotubes during thermal chemical vapour deposition

    International Nuclear Information System (INIS)

    Ohashi, Fumitaka; Chen, Guan Yow; Stolojan, Vlad; Silva, S Ravi P

    2008-01-01

    In this paper, we investigate the several roles that hydrogen plays in the catalytic growth of carbon nanotubes from the point of view of gas species, catalyst activation and subsequent interaction with the carbon nanotubes. Carbon nanotubes and nanofibres were grown by thermal chemical vapour deposition, using methane and a mixture of hydrogen and helium, for a range of growth temperatures and pre-treatment procedures. Long, straight carbon nanotubes were obtained at 900 deg. C, and although the growth yield increases with the growth temperature, the growth shifts from nanotubes to nanofibres. By introducing a helium purge as part of the pre-treatment procedure, we change the gas chemistry by altering the hydrogen concentration in the initial reaction stage. This simple change in the process resulted in a clear difference in the yield and the structure of the carbon nanofibres produced. We find that the hydrogen concentration in the initial reaction stage significantly affects the morphology of carbon fibres. Although hydrogen keeps the catalyst activated and increases the yield, it prevents the formation of graphitic nanotubes.

  19. Chemical Composition and Insecticidal Activity of Essential Oils from Zanthoxylum dissitum Leaves and Roots against Three Species of Storage Pests.

    Science.gov (United States)

    Wang, Cheng-Fang; Yang, Kai; You, Chun-Xue; Zhang, Wen-Juan; Guo, Shan-Shan; Geng, Zhu-Feng; Du, Shu-Shan; Wang, Yong-Yan

    2015-05-04

    This work aimed to investigate chemical composition of essential oils obtained from Zanthoxylum dissitum leaves and roots and their insecticidal activities against several stored product pests, namely the cigarette beetle (Lasioderma serricorne), red flour beetle (Tribolium castaneum) and black carpet beetle (Attagenus piceus). The analysis by GC-MS of the essential oils allowed the identification of 28 and 22 components, respectively. It was found that sesquiterpenoids comprised a fairly high portion of the two essential oils, with percentages of 74.0% and 80.9% in the leaves and roots, respectively. The main constituents identified in the essential oil of Z. dissitum leaves were δ-cadinol (12.8%), caryophyllene (12.7%), β-cubebene (7.9%), 4-terpineol (7.5%) and germacrene D-4-ol (5.7%), while humulene epoxide II (29.4%), caryophyllene oxide (24.0%), diepicedrene-1-oxide (10.7%) and Z,Z,Z-1,5,9,9-tetramethyl-1,4,7-cycloundecatriene (8.7%) were the major components in the essential oil of Z. dissitum roots. The insecticidal activity results indicated that the essential oil of Z. dissitum roots exhibited moderate contact toxicity against three species of storage pests, L. serricorne,T. castaneum and A. piceus, with LD50 values of 13.8, 43.7 and 96.8 µg/adult, respectively.

  20. Criteria on global boundedness versus finite time blow-up to a two-species chemotaxis system with two chemicals

    Science.gov (United States)

    Yu, Hao; Wang, Wei; Zheng, Sining

    2018-02-01

    This paper considers the two-species chemotaxis system with two chemicals in a smooth bounded domain Ω\\subset{R}2 , subject to the non-flux boundary condition, and χ, ξ, α, β, γ, δ>0 . We obtain a blow-up criterion that if m_1m_2-2π(\\frac{m_1}χβ+\\frac{m_2}ξδ)>0 , then there exist finite time blow-up solutions to the system with m_1:=\\int_Ω u_0(x)dx and m_2:=\\int_Ω w_0(x)dx . When χ=ξ= β=δ=1 , the blow-up criterion becomes m_1m_2-2π(m_1+m_2)>0 , and the global boundedness of solutions is furthermore established with α=γ=1 under the condition that \\max\\{m_1, m_2\\}4π and global boundedness with \\max\\{m_1, m_2\\}Funds for the Central Universities (DUT16LK24).

  1. The Effect of Chemical Treatments on Lampenflora and a Collembola Indicator Species at a Popular Tour Cave in California, USA

    Science.gov (United States)

    Meyer, Erik; Seale, L. Don; Permar, Brianne; McClary, Andrew

    2017-06-01

    Growth of invasive, opportunistic plants (i.e. lampenflora) in popular tour caves is a significant concern for land managers worldwide. Numerous chemicals at various concentrations have been utilized to remove phototrophic lampenflora colonizing artificially lit surfaces within these caves; however formulations, effectiveness, and impacts appear anecdotal and temporally limited. At Crystal Cave, Sequoia National Park, California, we study lampenflora and cave springtail ( Tomocerus celsus) response to a single 0.05 ml/cm2 dose of 1.0% sodium hypochlorite, 0.5% sodium hypochlorite, and 15.0% hydrogen peroxide compared to no treatment over the course of one year. Additionally, we explore potential food web impacts resulting from invasive lampenflora in naturally oligotrophic caves by utilizing stable isotope analysis of T. celsus found on and off lampenflora. Time-effect decay models indicate 1.0 and 0.5% sodium hypochlorite effectively eliminate lampenflora in 11 and 21 days, respectively, while lampenflora decay projections exceed 600 days with 15.0% hydrogen peroxide treatment. Repeat surveys of T. celsus indicate a negative response to 1.0% sodium hypochlorite ( P = 0.02), and the probability of observing T. celsus was inversely related to the effectiveness of each treatment. Further, T. celsus had similar diets regardless of their lampenflora association ( P = 0.92). We conclude that treatments of sodium hypochlorite at or below 0.5% achieve management goals with limited impacts to the presence or diet of a common cave-adapted indicator species.

  2. Analysis of Chemical Species Along the Process Stages of Demineralized Water Production at Reactor G.A. Siwabessy

    International Nuclear Information System (INIS)

    Nurul Huda; Setyono; Sumijanto; Diah E L; Ihsan, M.

    2003-01-01

    The tank water of multipurpose reactor G.A. Siwabessy is supplied from a water demineralization plant which works based on ion exchange processes. Controlling the quality of the water produced by this plant is one of many factor which effects the quality of the reactor tank water. This experiment resulted a characteristic pattern data of water and its chemical species content along process stages of demineralized water production at the reactor. The experiment results showed that the pH (degree of acidity), electric conductivity and dissolved cation (Ca 2+ , Mg 2+ ) lied at the permissible range. The value fluctuation of these variables showed a right pattern. It can be concluded that the water produced by this plant met the requirements to be used as primary cooling water of the reactor. However, the value of pH is still too low although it lied in the tolerance limit. Beside that, it isn't all of water impurities concentration can be predicted by the value of pH and conductivity. Therefore, the determination of water quality for the need of reactor tank water quiet to be done continually to keep the water condition in order to meet the quality required, and to evaluate and developed its production technology. (author)

  3. Gene expression responses of HeLa cells to chemical species generated by an atmospheric plasma flow

    Energy Technology Data Exchange (ETDEWEB)

    Yokoyama, Mayo, E-mail: yokoyama@plasma.ifs.tohoku.ac.jp [Institute of Fluid Science, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577 (Japan); Johkura, Kohei, E-mail: kohei@shinshu-u.ac.jp [Department of Histology and Embryology, Shinshu University School of Medicine, 3-1-1 Asahi, Matsumoto 390-8621 (Japan); Sato, Takehiko, E-mail: sato@ifs.tohoku.ac.jp [Institute of Fluid Science, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577 (Japan)

    2014-08-08

    Highlights: • Response of HeLa cells to a plasma-irradiated medium was revealed by DNA microarray. • Gene expression pattern was basically different from that in a H{sub 2}O{sub 2}-added medium. • Prominently up-/down-regulated genes were partly shared by the two media. • Gene ontology analysis showed both similar and different responses in the two media. • Candidate genes involved in response to ROS were detected in each medium. - Abstract: Plasma irradiation generates many factors able to affect the cellular condition, and this feature has been studied for its application in the field of medicine. We previously reported that hydrogen peroxide (H{sub 2}O{sub 2}) was the major cause of HeLa cell death among the chemical species generated by high level irradiation of a culture medium by atmospheric plasma. To assess the effect of plasma-induced factors on the response of live cells, HeLa cells were exposed to a medium irradiated by a non-lethal plasma flow level, and their gene expression was broadly analyzed by DNA microarray in comparison with that in a corresponding concentration of 51 μM H{sub 2}O{sub 2}. As a result, though the cell viability was sufficiently maintained at more than 90% in both cases, the plasma-medium had a greater impact on it than the H{sub 2}O{sub 2}-medium. Hierarchical clustering analysis revealed fundamentally different cellular responses between these two media. A larger population of genes was upregulated in the plasma-medium, whereas genes were downregulated in the H{sub 2}O{sub 2}-medium. However, a part of the genes that showed prominent differential expression was shared by them, including an immediate early gene ID2. In gene ontology analysis of upregulated genes, the plasma-medium showed more diverse ontologies than the H{sub 2}O{sub 2}-medium, whereas ontologies such as “response to stimulus” were common, and several genes corresponded to “response to reactive oxygen species.” Genes of AP-1 proteins, e.g., JUN

  4. Relationships between respiration, chemical and microbial properties of afforested mine soils with different soil texture and tree species: Does the time of incubation matter

    Czech Academy of Sciences Publication Activity Database

    Józefowska, A.; Pietrzykowski, M.; Woś, B.; Cajthaml, T.; Frouz, Jan

    2017-01-01

    Roč. 80, May (2017), s. 102-109 ISSN 1164-5563 Institutional support: RVO:60077344 Keywords : afforested mine soils * soil texture * tree species * chemical properties * microbial properties Subject RIV: DF - Soil Science OBOR OECD: Soil science Impact factor: 2.445, year: 2016

  5. Chemical characterization of 21 species of marine macroalgae common in Norwegian waters: benefits of and limitations to their potential use in food and feed.

    Science.gov (United States)

    Biancarosa, Irene; Belghit, Ikram; Bruckner, Christian G; Liland, Nina S; Waagbø, Rune; Amlund, Heidi; Heesch, Svenja; Lock, Erik-Jan

    2018-03-01

    In the past few years, much effort has been invested into developing a new blue economy based on harvesting, cultivating and processing marine macroalgae in Norway. Macroalgae have high potential for a wide range of applications, e.g. as source of pharmaceuticals, production of biofuels or as food and feed. However, data on the chemical composition of macroalgae from Norwegian waters are scant. This study was designed to characterize the chemical composition of 21 algal species. Both macro- and micronutrients were analysed. Concentrations of heavy metals and the metalloid arsenic in the algae were also quantified. The results confirm that marine macroalgae contain nutrients which are relevant for both human and animal nutrition, the concentrations whereof are highly dependent on species. Although heavy metals and arsenic were detected in the algae studied, concentrations were mostly below maximum allowed levels set by food and feed legislation in the EU. This study provides chemical data on a wide range of algal species covering the three taxonomic groups (brown, red and green algae) and discusses both benefits of and potential limitations to their use for food and feed purposes. © 2017 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. © 2017 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

  6. Second law analysis of a reacting temperature dependent viscous ...

    African Journals Online (AJOL)

    In this paper, entropy generation during the flow of a reacting viscous fluid through an inclined Channel with isothermal walls are investigated. The coupled energy and momentum equations were solved numerically. Previous results in literature (Adesanya et al 2006 [[17]) showed both velocity and temperature have two ...

  7. Three-dimensional reacting shock–bubble interaction

    NARCIS (Netherlands)

    Diegelmann, Felix; Hickel, S.; Adams, Nikolaus A.

    2017-01-01

    We investigate a reacting shock–bubble interaction through three-dimensional numerical simulations with detailed chemistry. The convex shape of the bubble focuses the shock and generates regions of high pressure and temperature, which are sufficient to ignite the diluted stoichiometric

  8. Large-Eddy Simulations of Reacting Liquid Spray

    Science.gov (United States)

    Lederlin, Thomas; Sanjose, Marlene; Gicquel, Laurent; Cuenot, Benedicte; Pitsch, Heinz; Poinsot, Thierry

    2008-11-01

    Numerical simulation, which is commonly used in many stages of aero-engine design, still has to demonstrate its predictive capability for two-phase reacting flows. This study is a collaboration between Stanford University and CERFACS to perform LES of a realistic spray combustor installed at ONERA, Toulouse. The experimental configuration is computed on the same unstructured mesh with two different solvers: Stanford's CDP code and CERFACS's AVBP code. CDP uses a low-Mach, variable-density solver with implicit time advancement. Droplets are tracked in a Lagrangian point-particle framework. The combustion model uses a flamelet approach, based on two transported scalars, mixture fraction and reaction progress variable. AVBP is a fully compressible solver with explicit time advancement. The liquid phase is described with an Eulerian method. The flame-turbulence interaction is modeled using a dynamically-thickened flame. Results are compared with experimental data for three regimes: purely gaseous non-reacting flow, non-reacting flow with evaporating droplets, reacting flow with droplets. Both simulations show a good agreement with experimental data and also stress the difference and relative advantages of the numerical methods.

  9. Characterization of forced response of density stratified reacting wake

    Science.gov (United States)

    Pawar, Samadhan A.; Sujith, Raman I.; Emerson, Benjamin; Lieuwen, Tim

    2018-02-01

    The hydrodynamic stability of a reacting wake depends primarily on the density ratio [i.e., ratio of unburnt gas density (ρu) to burnt gas density (ρb)] of the flow across the wake. The variation of the density ratio from high to low value, keeping ρ u / ρ b > 1 , transitions dynamical characteristics of the reacting wake from a linearly globally stable (or convectively unstable) to a globally unstable mode. In this paper, we propose a framework to analyze the effect of harmonic forcing on the deterministic and synchronization characteristics of reacting wakes. Using the recurrence quantification analysis of the forced wake response, we show that the deterministic behaviour of the reacting wake increases as the amplitude of forcing is increased. Furthermore, for different density ratios, we found that the synchronization of the top and bottom branches of the wake with the forcing signal is dependent on whether the mean frequency of the natural oscillations of the wake (fn) is lesser or greater than the frequency of external forcing (ff). We notice that the response of both branches (top and bottom) of the reacting wake to the external forcing is asymmetric and symmetric for the low and high density ratios, respectively. Furthermore, we characterize the phase-locking behaviour between the top and bottom branches of the wake for different values of density ratios. We observe that an increase in the density ratio results in a gradual decrease in the relative phase angle between the top and bottom branches of the wake, which leads to a change in the vortex shedding pattern from a sinuous (anti-phase) to a varicose (in-phase) mode of the oscillations.

  10. Effects of cultivation conditions on the uptake of arsenite and arsenic chemical species accumulated by Pteris vittata in hydroponics.

    Science.gov (United States)

    Hatayama, Masayoshi; Sato, Takahiko; Shinoda, Kozo; Inoue, Chihiro

    2011-03-01

    The physiological responses of the arsenic-hyperaccumulator, Pteris vittata, such as arsenic uptake and chemical transformation in the fern, have been investigated. However, a few questions remain regarding arsenic treatment in hydroponics. Incubation conditions such as aeration, arsenic concentration, and incubation period might affect those responses of P. vittata in hydroponics. Arsenite uptake was low under anaerobic conditions, as previously reported. However, in an arsenite uptake experiment, phosphorous (P) starvation-dependent uptake of arsenate was observed under aerobic conditions. Time course-dependent analysis of arsenite oxidation showed that arsenite was gradually oxidized to arsenate during incubation. Arsenite oxidation was not observed in any of the control conditions, such as exposure to a nutrient solution or to culture medium only, or with the use of dried root; arsenite oxidation was only observed when live root was used. This result suggests that sufficient aeration allows the rhizosphere system to oxidize arsenite and enables the fern to efficiently take up arsenite as arsenate. X-ray absorption near edge structure (XANES) analyses showed that long-duration exposure to arsenic using a hydroponic system led to the accumulation of arsenate as the dominant species in the root tips, but not in the whole roots, partly because up-regulation of arsenate uptake by P starvation of the fern was caused and retained by long-time incubation. Analysis of concentration-dependent arsenate uptake by P. vittata showed that the uptake switched from a high-affinity transport system to a low-affinity system at high arsenate concentrations, which partially explains the increased arsenate abundance in the whole root. Copyright © 2010 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  11. Demonstration of Fast and Accurate Discrimination and Quantification of Chemically Similar Species Utilizing a Single Cross-Selective Chemiresistor

    Science.gov (United States)

    2015-01-01

    Performance characteristics of gas-phase microsensors will determine the ultimate utility of these devices for a wide range of chemical monitoring applications. Commonly employed chemiresistor elements are quite sensitive to selected analytes, and relatively new methods have increased the selectivity to specific compounds, even in the presence of interfering species. Here, we have focused on determining whether purposefully driven temperature modulation can produce faster sensor-response characteristics, which could enable measurements for a broader range of applications involving dynamic compositional analysis. We investigated the response speed of a single chemiresitive In2O3 microhotplate sensor to four analytes (methanol, ethanol, acetone, 2-butanone) by systematically varying the oscillating frequency (semicycle periods of 20–120 ms) of a bilevel temperature cycle applied to the sensing element. It was determined that the fastest response (≈ 9 s), as indicated by a 98% signal-change metric, occurred for a period of 30 ms and that responses under such modulation were dramatically faster than for isothermal operation of the same device (>300 s). Rapid modulation between 150 and 450 °C exerts kinetic control over transient processes, including adsorption, desorption, diffusion, and reaction phenomena, which are important for charge transfer occurring in transduction processes and the observed response times. We also demonstrate that the fastest operation is accompanied by excellent discrimination within a challenging 16-category recognition problem (consisting of the four analytes at four separate concentrations). This critical finding demonstrates that both speed and high discriminatory capabilities can be realized through temperature modulation. PMID:24931319

  12. Chemical Analysis and Biological Activity of the Essential Oils of Two Valerianaceous Species from China: Nardostachys chinensis and Valeriana officinalis

    Directory of Open Access Journals (Sweden)

    Jianglin Zhao

    2010-09-01

    Full Text Available In order to investigate essential oils with biological activity from local wild plants, two valerianaceous species, Nardostachys chinensis and Valeriana officinalis, were screened for their antimicrobial and antioxidant activity. The essential oils were obtained from the roots and rhizomes of the two plants by hydro-distillation, and were analyzed for their chemical composition by gas chromatography (GC and gas chromatography-mass spectrometry (GC-MS. Calarene (25.31%, aristolone (13.35%, α-selinene (7.32% and β-maaliene (6.70% were the major compounds of the 23 identified components which accounted for 92.76% of the total oil of N. chinensis. Patchoulol (16.75%, α-pinene (14.81%, and β-humulene (8.19% were the major compounds among the 20 identified components, which accounted for 88.11% of the total oil of V. officinalis. Both oils were rich in sesquiterpene hydrocarbons as well as their oxygenated derivatives. Essential oils were shown to have broad spectrum antibacterial activity with MIC values that ranged from 62.5 μg/mL to 400 μg/mL, and IC50 values from 36.93 μg/mL to 374.72 μg/mL. The oils were also shown to have moderate antifungal activity to Candida albicans growth as well as inhibition of spore germination of Magnaporthe oryzae. Two essential oils were assessed by 1,1-diphenyl-2-picrylhydrazyl (DPPH free radical scavenging, β-carotene bleaching and ferrozine-ferrous ions assays, respectively, to show moderate antioxidant activity. Results suggest that the isolated essential oils could be used for future development of antimicrobial and antioxidant agents.

  13. Cross talk between increased intracellular zinc (Zn2+) and accumulation of reactive oxygen species in chemical ischemia.

    Science.gov (United States)

    Slepchenko, Kira G; Lu, Qiping; Li, Yang V

    2017-10-01

    Both zinc (Zn 2+ ) and reactive oxygen species (ROS) have been shown to accumulate during hypoxic-ischemic stress and play important roles in pathological processes. To understand the cross talk between the two of them, here we studied Zn 2+ and ROS accumulation by employing fluorescent probes in HeLa cells to further the understanding of the cause and effect relationship of these two important cellular signaling systems during chemical-ischemia, stimulated by oxygen and glucose deprivation (OGD). We observed two Zn 2+ rises that were divided into four phases in the course of 30 min of OGD. The first Zn 2+ rise was a transient, which was followed by a latent phase during which Zn 2+ levels recovered; however, levels remained above a basal level in most cells. The final phase was the second Zn 2+ rise, which reached a sustained plateau called Zn 2+ overload. Zn 2+ rises were not observed when Zn 2+ was removed by TPEN (a Zn 2+ chelator) or thapsigargin (depleting Zn 2+ from intracellular stores) treatment, indicating that Zn 2+ was from intracellular storage. Damaging mitochondria with FCCP significantly reduced the second Zn 2+ rise, indicating that the mitochondrial Zn 2+ accumulation contributes to Zn 2+ overload. We also detected two OGD-induced ROS rises. Two Zn 2+ rises preceded two ROS rises. Removal of Zn 2+ reduced or delayed OGD- and FCCP-induced ROS generation, indicating that Zn 2+ contributes to mitochondrial ROS generation. There was a Zn 2+ -induced increase in the functional component of NADPH oxidase, p47 phox , thus suggesting that NADPH oxidase may mediate Zn 2+ -induced ROS accumulation. We suggest a new mechanism of cross talk between Zn 2+ and mitochondrial ROS through positive feedback processes that eventually causes excessive free Zn 2+ and ROS accumulations during the course of ischemic stress. Copyright © 2017 the American Physiological Society.

  14. Solutions of the chemical kinetic equations for initially inhomogeneous mixtures.

    Science.gov (United States)

    Hilst, G. R.

    1973-01-01

    Following the recent discussions by O'Brien (1971) and Donaldson and Hilst (1972) of the effects of inhomogeneous mixing and turbulent diffusion on simple chemical reaction rates, the present report provides a more extensive analysis of when inhomogeneous mixing has a significant effect on chemical reaction rates. The analysis is then extended to the development of an approximate chemical sub-model which provides much improved predictions of chemical reaction rates over a wide range of inhomogeneities and pathological distributions of the concentrations of the reacting chemical species. In particular, the development of an approximate representation of the third-order correlations of the joint concentration fluctuations permits closure of the chemical sub-model at the level of the second-order moments of these fluctuations and the mean concentrations.

  15. Chemical characterization of 21 species of marine macroalgae common in Norwegian waters: benefits of and limitations to their potential use in food and feed

    Science.gov (United States)

    Biancarosa, Irene; Belghit, Ikram; Bruckner, Christian G; Liland, Nina S; Waagbø, Rune; Amlund, Heidi; Heesch, Svenja

    2018-01-01

    Abstract BACKGROUND In the past few years, much effort has been invested into developing a new blue economy based on harvesting, cultivating and processing marine macroalgae in Norway. Macroalgae have high potential for a wide range of applications, e.g. as source of pharmaceuticals, production of biofuels or as food and feed. However, data on the chemical composition of macroalgae from Norwegian waters are scant. This study was designed to characterize the chemical composition of 21 algal species. Both macro‐ and micronutrients were analysed. Concentrations of heavy metals and the metalloid arsenic in the algae were also quantified. RESULTS The results confirm that marine macroalgae contain nutrients which are relevant for both human and animal nutrition, the concentrations whereof are highly dependent on species. Although heavy metals and arsenic were detected in the algae studied, concentrations were mostly below maximum allowed levels set by food and feed legislation in the EU. CONCLUSION This study provides chemical data on a wide range of algal species covering the three taxonomic groups (brown, red and green algae) and discusses both benefits of and potential limitations to their use for food and feed purposes. © 2017 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. PMID:29193189

  16. A review of reaction rates and thermodynamic and transport properties for an 11-species air model for chemical and thermal nonequilibrium calculations to 30000 K

    Science.gov (United States)

    Gupta, Roop N.; Yos, Jerrold M.; Thompson, Richard A.; Lee, Kam-Pui

    1990-01-01

    Reaction rate coefficients and thermodynamic and transport properties are reviewed and supplemented for the 11-species air model which can be used for analyzing flows in chemical and thermal nonequilibrium up to temperatures of 3000 K. Such flows will likely occur around currently planned and future hypersonic vehicles. Guidelines for determining the state of the surrounding environment are provided. Curve fits are given for the various species properties for their efficient computation in flowfield codes. Approximate and more exact formulas are provided for computing the properties of partially ionized air mixtures in a high energy environment. Limitations of the approximate mixing laws are discussed for a mixture of ionized species. An electron number-density correction for the transport properties of the charged species is obtained. This correction has been generally ignored in the literature.

  17. IgE antibodies of fish allergic patients cross-react with frog parvalbumin.

    Science.gov (United States)

    Hilger, C; Thill, L; Grigioni, F; Lehners, C; Falagiani, P; Ferrara, A; Romano, C; Stevens, W; Hentges, F

    2004-06-01

    The major allergens in fish are parvalbumins. Important immunoglobulin (Ig)E cross-recognition of parvalbumins from different fish species has been shown. Recently frog parvalbumin alpha has been found to be responsible for a case of IgE-mediated anaphylaxis triggered by the ingestion of frog meat. The aim of this study was to investigate whether IgE antibodies of fish allergic persons cross-react with frog parvalbumin and to appreciate its clinical relevance. The sera of 15 fish allergic patients and one fish and frog allergic patient were tested by IgE-immunoblotting against frog muscle extract. Sera were tested against recombinant parvalbumin alpha and beta from Rana esculenta. Skin prick tests were performed in selected patients with recombinant frog parvalbumin. Ca(2+) depletion experiments and inhibition studies with purified cod and frog recombinant parvalbumin were done to characterize the cross-reactive pattern. Fourteen of the sera tested had IgE antibodies recognizing low molecular weight components in frog muscle extract. Calcium depletion experiments or inhibition of patient sera with purified cod parvalbumin led to a significant or complete decrease in IgE binding. When tested against recombinant parvalbumins, three of 13 sera reacted with alpha parvalbumin and 11 of 12 reacted with beta parvalbumin from R. esculenta. Skin prick tests performed with recombinant frog parvalbumin were positive in fish allergic patients. Inhibition studies showed that a fish and frog allergic patient was primarily sensitized to fish parvalbumin. Cod parvalbumin, a major cross-reactive allergen among different fish species, shares IgE binding epitopes with frog parvalbumin. This in vitro cross-reactivity seems to be also clinically relevant. Parvalbumins probably represent a new family of cross-reactive allergens.

  18. Low Mach number asymptotics for reacting compressible fluid flows

    Czech Academy of Sciences Publication Activity Database

    Feireisl, Eduard; Petzeltová, Hana

    2010-01-01

    Roč. 26, č. 2 (2010), s. 455-480 ISSN 1078-0947 R&D Projects: GA ČR GA201/05/0164 Institutional research plan: CEZ:AV0Z10190503 Keywords : low Mach number * Navier-Stokes-Fourier system * reacting fluids Subject RIV: BA - General Mathematics Impact factor: 0.986, year: 2010 http://www.aimsciences.org/journals/displayArticles.jsp?paperID=4660

  19. Experimental thermodynamics experimental thermodynamics of non-reacting fluids

    CERN Document Server

    Neindre, B Le

    2013-01-01

    Experimental Thermodynamics, Volume II: Experimental Thermodynamics of Non-reacting Fluids focuses on experimental methods and procedures in the study of thermophysical properties of fluids. The selection first offers information on methods used in measuring thermodynamic properties and tests, including physical quantities and symbols for physical quantities, thermodynamic definitions, and definition of activities and related quantities. The text also describes reference materials for thermometric fixed points, temperature measurement under pressures, and pressure measurements. The publicatio

  20. Chromatographic speciation of Cr(III)-species, inter-species equilibrium isotope fractionation and improved chemical purification strategies for high-precision isotope analysis

    DEFF Research Database (Denmark)

    Larsen, Kirsten Kolbjørn; Wielandt, Daniel Kim Peel; Schiller, Martin

    2016-01-01

    Chromatographic purification of chromium (Cr), which is required for high-precision isotope analysis, is complicated by the presence of multiple Cr-species with different effective charges in the acid digested sample aliquots. The differing ion exchange selectivity and sluggish reaction rates of ...

  1. Influence of soil physical and chemical variables on species composition and richness of plants in the arid region of Tabuk, Saudi Arabia

    Directory of Open Access Journals (Sweden)

    Al-Mutairi Khalid Awadh

    2017-06-01

    Full Text Available The present study aims to investigate the effect of soil physical and chemical variables on the species richness and the floristic composition in four sites (Alwaz, Alqan, Sharma and Zetah of Tabuk region in the Northwestern part of Arabian Peninsula. Only organic matter (OM, pH and calcium (Ca showed significant differences (P < 0.05 amongst the four studied sites. Only magnesium and sodium were selected in the forward regression model and showed to be strong drivers of species richness of plants in Tabuk region (Adj-R2 = 0.438, F2,13 = 6.85, P = 0.009. The multivariate analysis of canonical correspondence analysis (CCA was applied to reveal the effect of the physical and chemical variables on the species composition of the plants. The CCA classifies the plant species into three groups based on their preference to the environmental variables. The first group of plant species (Group 1 is characterised by positive preference to the chloride (Cl and negative relationship with OM and pH. The second group (Group 2 is positively correlated with most of the soil variables such as OM, calcium (Ca, potassium (K, bicarbonate (HCO3, electrical conductivity (EC, sulphate (SO4 and sodium (Na. The third group (Group 3 has positive relationship with carbonate (CO3 and negative relationship with EC and magnesium (Mg. The chloride, sodium, sulphate, EC and carbonate are the main environmental factors influencing the plant species composition in Tabuk region. The cluster analysis based on the Euclidian measure shows that Alqan and Zetah have closer species composition compared to Sharma.

  2. Combining discrete equations method and upwind downwind-controlled splitting for non-reacting and reacting two-fluid computations

    International Nuclear Information System (INIS)

    Tang, K.

    2012-01-01

    When numerically investigating multiphase phenomena during severe accidents in a reactor system, characteristic lengths of the multi-fluid zone (non-reactive and reactive) are found to be much smaller than the volume of the reactor containment, which makes the direct modeling of the configuration hardly achievable. Alternatively, we propose to consider the physical multiphase mixture zone as an infinitely thin interface. Then, the reactive Riemann solver is inserted into the Reactive Discrete Equations Method (RDEM) to compute high speed combustion waves represented by discontinuous interfaces. An anti-diffusive approach is also coupled with RDEM to accurately simulate reactive interfaces. Increased robustness and efficiency when computing both multiphase interfaces and reacting flows are achieved thanks to an original upwind downwind-controlled splitting method (UDCS). UDCS is capable of accurately solving interfaces on multi-dimensional unstructured meshes, including reacting fronts for both deflagration and detonation configurations. (author)

  3. A review of reaction rates and thermodynamic and transport properties for the 11-species air model for chemical and thermal nonequilibrium calculations to 30000 K

    Science.gov (United States)

    Gupta, Roop N.; Yos, Jerrold M.; Thompson, Richard A.

    1989-01-01

    Reaction rate coefficients and thermodynamic and transport properties are provided for the 11-species air model which can be used for analyzing flows in chemical and thermal nonequilibrium. Such flows will likely occur around currently planned and future hypersonic vehicles. Guidelines for determining the state of the surrounding environment are provided. Approximate and more exact formulas are provided for computing the properties of partially ionized air mixtures in such environments.

  4. The Rules of Aggression: How Genetic, Chemical and Spatial Factors Affect Intercolony Fights in a Dominant Species, the Mediterranean Acrobat Ant Crematogaster scutellaris.

    Directory of Open Access Journals (Sweden)

    Filippo Frizzi

    Full Text Available Nest-mate recognition plays a key role in the biology of ants. Although individuals coming from a foreign nest are, in most cases, promptly rejected, the degree of aggressiveness towards non nest-mates may be highly variable among species and relies on genetic, chemical and environmental factors. We analyzed intraspecific relationships among neighboring colonies of the dominant Mediterranean acrobat ant Crematogaster scutellaris integrating genetic, chemical and behavioral analyses. Colony structure, parental relationships between nests, cuticular hydrocarbons profiles (CHCs and aggressive behavior against non nest-mates were studied in 34 nests located in olive tree trunks. Bayesian clustering analysis of allelic variation at nine species-specific microsatellite DNA markers pooled nests into 14 distinct clusters, each representing a single colony, confirming a polydomous arrangement of nests in this species. A marked genetic separation among colonies was also detected, probably due to long distance dispersion of queens and males during nuptial flights. CHCs profiles varied significantly among colonies and between nests of the same colony. No relationship between CHCs profiles and genetic distances was detected. The level of aggressiveness between colonies was inversely related to chemical and spatial distance, suggesting a 'nasty neighbor' effect. Our findings also suggest that CHCs profiles in C. scutellaris may be linked to external environmental factors rather than genetic relationships.

  5. Comparison of tropical and temperate freshwater animal species' acute sensitivities to chemicals: implications for deriving safe extrapolation factors

    NARCIS (Netherlands)

    Kwok, K.W.H.; Leung, K.M.Y.; Lui, G.S.G.; Chu, V.K.H.; Lam, P.K.S.; Morritt, D.; Maltby, L.; Brock, T.C.M.; Brink, van den P.J.; Warne, M.S.J.; Crane, M.

    2007-01-01

    Toxicity data for tropical species are often lacking for ecological risk assessment. Consequently, tropical and subtropical countries use water quality criteria (WQC) derived from temperate species (e.g., United States, Canada, or Europe) to assess ecological risks in their aquatic systems, leaving

  6. Plasma-activation of tap water using DBD for agronomy applications: Identification and quantification of long lifetime chemical species and production/consumption mechanisms.

    Science.gov (United States)

    Judée, F; Simon, S; Bailly, C; Dufour, T

    2018-04-15

    Cold atmospheric plasmas are weakly ionized gases that can be generated in ambient air. They produce energetic species (e.g. electrons, metastables) as well as reactive oxygen species, reactive nitrogen species, UV radiations and local electric field. Their interaction with a liquid such as tap water can hence change its chemical composition. The resulting "plasma-activated liquid" can meet many applications, including medicine and agriculture. Consequently, a complete experimental set of analytical techniques dedicated to the characterization of long lifetime chemical species has been implemented to characterize tap water treated using cold atmospheric plasma process and intended to agronomy applications. For that purpose, colorimetry and acid titrations are performed, considering acid-base equilibria, pH and temperature variations induced during plasma activation. 16 species are quantified and monitored: hydroxide and hydronium ions, ammonia and ammonium ions, orthophosphates, carbonate ions, nitrite and nitrate ions and hydrogen peroxide. The related consumption/production mechanisms are discussed. In parallel, a chemical model of electrical conductivity based on Kohlrausch's law has been developed to simulate the electrical conductivity of the plasma-activated tap water (PATW). Comparing its predictions with experimental measurements leads to a narrow fitting, hence supporting the self-sufficiency of the experimental set, I.e. the fact that all long lifetime radicals of interest present in PATW are characterized. Finally, to evaluate the potential of cold atmospheric plasmas for agriculture applications, tap water has been daily plasma-treated to irrigate lentils seeds. Then, seedlings lengths have been measured and compared with untreated tap water, showing an increase as high as 34.0% and 128.4% after 3 days and 6 days of activation respectively. The interaction mechanisms between plasma and tap water are discussed as well as their positive synergy on

  7. Microspectroscopic imaging of solution plasma: How do its physical properties and chemical species evolve in atmospheric-pressure water vapor bubbles?

    Science.gov (United States)

    Yui, Hiroharu; Banno, Motohiro

    2018-01-01

    In this article, we review the development of scientific instruments for obtaining information on the evolution of physical properties and chemical species of solution plasma (SP). When a pulsed high voltage is applied between electrodes immersed in an aqueous solution, SP is formed in water vapor bubbles transiently generated in the solution under atmospheric pressure. To clarify how SP emerges in water vapor bubbles and is sustained in solutions, an instrument with micrometer spatial resolution and nanosecond temporal resolution is required. To meet these requirements, a microscopic system with a custom-made optical discharge cell was newly developed, where the working distance between the SP and the microscopic objective lens was minimized. A hollow electrode equipped in the discharge cell also enabled us to control the chemical composition in water vapor bubbles. To study the spatial and temporal evolutions of chemical species in micrometer and nano- to microsecond regions, a streak camera with a spectrometer and a CCD detector with a time-gated electronic device were combined with the microscope system. The developed instrument is expected to contribute to providing a new means of developing new schemes for chemical reactions and material syntheses.

  8. Use of chemical elements of 1A family by tropical tree species; Uso de elementos quimicos da familia 1A por especies arboreas tropicais

    Energy Technology Data Exchange (ETDEWEB)

    Carmo, Andrius M.J.; Paiva, Jose Daniel S. de; Magalhaes, Marcelo R.L. de; Franca, Elvis J. de; Hazin, Clovis A., E-mail: ejfranca@cnen.gov.br [Centro Regional de Ciencias Nucleares do Nordeste (CRCN-NE/CNEN-PE), Recife, PE (Brazil); Bacchi, Marcio A.; Fernandes, Elisabete A.N., E-mail: mabacchi@cena.usp.br [Centro de Energia Nuclear na Agricultura (CENA/USP), Piracicaba, SP (Brazil).

    2013-07-01

    This study aims to evaluate the distribution of K, Rb and Cs in leaves of trees of the Atlantic Forest through studies of correlation between the chemical elements. For this, we used the Instrumental Neutron Activation Analysis for the quantification of the chemical elements. The concentration ranges found were 6700-24000 mg / kg for K, 16 to 72mg / kg for Rb and 0.08 to 0,92mg / kg for Cs. As Rb has chemical similarity to K, is easily absorbed by plants, leading to a high value (0.9) of the Pearson correlation. For the correlation between K and Cs, no significant values were detected except for some species of the Myrtaceae family. However, average correlations (0.6 species of different families. The absence of a specific pattern using of K, Rb and Cs by plants showed great complexity in the distribution of chemical elements in the ecosystem.

  9. Potential performance improvement using a reacting gas (nitrogin tetroxide) as the working fluid in a closed Brayton cycle

    Science.gov (United States)

    Stochl, R. J.

    1979-01-01

    The results of an analysis to estimate the performance that could be obtained by using a chemically reacting gas (nitrogen tetroxide) as the working fluid in a closed Brayton cycle are presented. Compared with data for helium as the working fluid, these results indicate efficiency improvements from 4 to 90 percent, depending on turbine inlet temperature, pressures, and gas residence time in heat transfer equipment.

  10. Assessment of pollution along the Northern Iberian shelf by the combined use of chemical and biochemical markers in two representative fish species

    International Nuclear Information System (INIS)

    Fernandes, Denise; Andreu-Sanchez, Oscar; Bebianno, Maria Joao; Porte, Cinta

    2008-01-01

    Muscle concentrations of organochlorinated compounds as well as biliary levels of polycyclic aromatic hydrocarbons (PAHs) and alkylphenols (APEs) were determined in two different fish species, the four-spotted megrim (Lepidorhombus boscii) and the pouting (Trisopterus luscus) collected along the Northern Iberian coast. Additionally, a set of biochemical markers namely, 7-ethoxyresorufin O-deethylase (EROD), UDP-glucuronosyltransferase (UGT) and catalase (CAT) were measured in liver subcellular fractions. Chemical analysis indicated geographical differences in pollutant loads that were further reinforced by biomarker responses. Thus, EROD activity showed a good correlation with the amount of PCBs bioaccumulated in muscle tissue of both fish species. Elevated UGT activity was observed in those individuals highly exposed to APEs and 1-naphthol. The study reinforces the need to select representative sentinel species from different habitats for biomonitoring purposes and provides further support for the use of biomarkers in assessing the health of coastal areas. - Pollution biomonitoring along the Northern Iberian Shelf by the combined use of chemical and biochemical tools in two representative fish species

  11. Assessment of pollution along the Northern Iberian shelf by the combined use of chemical and biochemical markers in two representative fish species

    Energy Technology Data Exchange (ETDEWEB)

    Fernandes, Denise [CIMA, University of Algarve, FCMA, Campus de Gambelas, 8005-139 Faro (Portugal); Department of Environmental Chemistry, IIQAB-CSIC, Jordi Girona 18, 08034 Barcelona (Spain); Andreu-Sanchez, Oscar [Polytechnic University Valencia, E.T.S.I. Agronomy, Biotechnology Department, 46022, Valencia (Spain); Bebianno, Maria Joao [CIMA, University of Algarve, FCMA, Campus de Gambelas, 8005-139 Faro (Portugal); Porte, Cinta [Department of Environmental Chemistry, IIQAB-CSIC, Jordi Girona 18, 08034 Barcelona (Spain)], E-mail: cpvqam@cid.csic.es

    2008-09-15

    Muscle concentrations of organochlorinated compounds as well as biliary levels of polycyclic aromatic hydrocarbons (PAHs) and alkylphenols (APEs) were determined in two different fish species, the four-spotted megrim (Lepidorhombus boscii) and the pouting (Trisopterus luscus) collected along the Northern Iberian coast. Additionally, a set of biochemical markers namely, 7-ethoxyresorufin O-deethylase (EROD), UDP-glucuronosyltransferase (UGT) and catalase (CAT) were measured in liver subcellular fractions. Chemical analysis indicated geographical differences in pollutant loads that were further reinforced by biomarker responses. Thus, EROD activity showed a good correlation with the amount of PCBs bioaccumulated in muscle tissue of both fish species. Elevated UGT activity was observed in those individuals highly exposed to APEs and 1-naphthol. The study reinforces the need to select representative sentinel species from different habitats for biomonitoring purposes and provides further support for the use of biomarkers in assessing the health of coastal areas. - Pollution biomonitoring along the Northern Iberian Shelf by the combined use of chemical and biochemical tools in two representative fish species.

  12. Toxicity and utilization of chemical weapons: does toxicity and venom utilization contribute to the formation of species communities?

    Science.gov (United States)

    Westermann, Fabian L; McPherson, Iain S; Jones, Tappey H; Milicich, Lesley; Lester, Philip J

    2015-08-01

    Toxicity and the utilization of venom are essential features in the ecology of many animal species and have been hypothesized to be important factors contributing to the assembly of communities through competitive interactions. Ants of the genus Monomorium utilize a variety of venom compositions, which have been reported to give them a competitive advantage. Here, we investigate two pairs of Monomorium species, which differ in the structural compositions of their venom and their co-occurrence patterns with the invasive Argentine ant. We looked at the effects of Monomorium venom toxicity, venom utilization, and aggressive physical interactions on Monomorium and Argentine ant survival rates during arena trials. The venom toxicity of the two species co-occurring with the invasive Argentine ants was found to be significantly higher than the toxicity of the two species which do not. There was no correlation between venom toxicity and Monomorium survival; however, three of the four Monomorium species displayed significant variability in their venom usage which was associated with the number of Argentine ant workers encountered during trials. Average Monomorium mortality varied significantly between species, and in Monomorium smithii and Monomorium antipodum, aggressive interactions with Argentine ants had a significant negative effect on their mortality. Our study demonstrates that different factors and strategies can contribute to the ability of a species to withstand the pressure of a dominant invader at high abundance, and venom chemistry appears to be only one of several strategies utilized.

  13. The effects of wood storage on the chemical composition and indigenous microflora of eucalyptus species used in the pulping industry

    CSIR Research Space (South Africa)

    Ramnath, L

    2018-02-01

    Full Text Available Lipophilic extractives naturally occurring in wood tend to coalesce during pulping to form pitch deposits, which have particularly undesirable effects on the pulping process and quality of pulp produced. A chemical characterization of different...

  14. A rapid method for the computation of equilibrium chemical composition of air to 15000 K

    Science.gov (United States)

    Prabhu, Ramadas K.; Erickson, Wayne D.

    1988-01-01

    A rapid computational method has been developed to determine the chemical composition of equilibrium air to 15000 K. Eleven chemically reacting species, i.e., O2, N2, O, NO, N, NO+, e-, N+, O+, Ar, and Ar+ are included. The method involves combining algebraically seven nonlinear equilibrium equations and four linear elemental mass balance and charge neutrality equations. Computational speeds for determining the equilibrium chemical composition are significantly faster than the often used free energy minimization procedure. Data are also included from which the thermodynamic properties of air can be computed. A listing of the computer program together with a set of sample results are included.

  15. High-performance metabolic profiling of plasma from seven mammalian species for simultaneous environmental chemical surveillance and bioeffect monitoring

    OpenAIRE

    Park, Youngja H.; Lee, Kichun; Soltow, Quinlyn A.; Strobel, Frederick H.; Brigham, Kenneth L.; Parker, Richard E.; Wilson, Mark E.; Sutliff, Roy L.; Mansfield, Keith G.; Wachtman, Lynn M.; Ziegler, Thomas R.; Jones, Dean P.

    2012-01-01

    High-performance metabolic profiling (HPMP) by Fourier-transform mass spectrometry coupled to liquid chromatography gives relative quantification of thousands of chemicals in biologic samples but has had little development for use in toxicology research. In principle, the approach could be useful to detect complex metabolic response patterns to toxicologic exposures and to detect unusual abundances or patterns of potentially toxic chemicals. As an initial study to develop these possible uses,...

  16. Steam sauna and mother roasting in Lao PDR: practices and chemical constituents of essential oils of plant species used in postpartum recovery

    Science.gov (United States)

    2011-01-01

    Background Fundamental in traditional postpartum recovery in Lao PDR is the use of hotbeds, mother roasting, steam sauna and steam baths. During these treatments medicinal plants play a crucial role, but little has been published about how the treatments are carried out precisely, which species are used, the medicinal properties of these species, and the medicinal efficacy of their chemical constituents. Methods Sixty-five interviews, in 15 rural villages, with women of 4 different ethnic groups were conducted to survey confinement rituals, and postpartum plant use and salience. Essential oils from the main species used were extracted using steam distillation and the main chemical constituents characterized using gas chromatography-mass spectrometry (GC-MS). Results A total of 10 different species were used by three or more of the ethnic groups included in this study. All species were used in steam sauna and bath, but only 3 species were used in hotbed and mother roasting. Essential oils of Amomum villosum, Amomum microcarpum and Blumea balsamifera were found to contain significant amounts of the following terpenes: β-pinene, camphor, bornyl acetate, borneol, linalool, D-limonene, fenchone, terpinen-4-ol and α-terpinene. Conclusions Many of these terpenes have documented antimicrobial and analgesic properties, and some have also synergistic interactions with other terpenes. The mode of application in hotbed and mother roasting differs from the documented mechanisms of action of these terpenes. Plants in these two practices are likely to serve mainly hygienic purposes, by segregating the mother from infection sources such as beds, mats, stools, cloth and towels. Steam sauna medicinal plant use through inhalation of essential oils vapors can possibly have medicinal efficacy, but is unlikely to alleviate the ailments commonly encountered during postpartum convalescence. Steam sauna medicinal plant use through dermal condensation of essential oils, and steam bath

  17. SQL Triggers Reacting on Time Events: An Extension Proposal

    Science.gov (United States)

    Behrend, Andreas; Dorau, Christian; Manthey, Rainer

    Being able to activate triggers at timepoints reached or after time intervals elapsed has been acknowledged by many authors as a valuable functionality of a DBMS. Recently, the interest in time-based triggers has been renewed in the context of data stream monitoring. However, up till now SQL triggers react to data changes only, even though research proposals and prototypes have been supporting several other event types, in particular time-based ones, since long. We therefore propose a seamless extension of the SQL trigger concept by time-based triggers, focussing on semantic issues arising from such an extension.

  18. Tax havens under international pressure: How do they react?

    OpenAIRE

    Patrice Pieretti; Giuseppe Pulina

    2015-01-01

    This paper contributes to the literature about tax havens by providing a more comprehensive analysis of their role. The aim is to analyze how low-tax jurisdictions can react to growing international pressure exerted, by high-tax countries, to enforce compliance with anti aggressive tax planning standards. To this end, we model how a small tax haven tries to be attractive to multinationals located in a high-tax region by providing aggressive tax planning services and/or a favorable environment...

  19. ReACT Methodology Proof of Concept Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Bri Rolston; Sarah Freeman

    2014-03-01

    The Department of Energy’s Office of Electricity Delivery and Energy Reliability (DOE-OE) funded INL Researchers to evaluate a novel process for assessing and mitigating cyber security risks. The proof of concept level of the method was tested in an industry environment. This case study, plus additional case studies will support the further development of the method into a tool to assist industry in securing their critical networks. This report provides an understanding of the process developed in the Response Analysis and Characterization Tool (ReACT) project. This report concludes with lessons learned and a roadmap for final development of these tools for use by industry.

  20. Numerical simulation of low Mach number reacting flows

    International Nuclear Information System (INIS)

    Bell, J B; Aspden, A J; Day, M S; Lijewski, M J

    2007-01-01

    Using examples from active research areas in combustion and astrophysics, we demonstrate a computationally efficient numerical approach for simulating multiscale low Mach number reacting flows. The method enables simulations that incorporate an unprecedented range of temporal and spatial scales, while at the same time, allows an extremely high degree of reaction fidelity. Sample applications demonstrate the efficiency of the approach with respect to a traditional time-explicit integration method, and the utility of the methodology for studying the interaction of turbulence with terrestrial and astrophysical flame structures

  1. Comparison of the chemical composition of three species of smartweed (genus Persicaria) with a focus on drimane sesquiterpenoids

    NARCIS (Netherlands)

    Prota, N.; Mumm, R.; Bouwmeester, H.J.; Jongsma, M.A.

    2014-01-01

    The genus Persicaria is known to include species accumulating drimane sesquiterpenoids, but a comparative analysis highlighting the compositional differences has not been done. In this study, the secondary metabolites of both flowers and leaves of Persicaria hydropiper, Persicaria maculosa and

  2. Chemical and biological study of essential oils from Eugenia pruniformis cambess., an endemic species from Brazilian Atlantic Forest

    OpenAIRE

    Albuquerque, Ricardo D.D.G.; Tietbohl, Luis A. C.; Fernandes, Caio P.; Couteiro, Pedro P.; Eiriz, Débora N.; Santos, Marcelo G.; Silva Filho, Moacélio V.; Alves, Gutemberg G.; Bachinski, Róber; Rocha, Leandro

    2012-01-01

    Eugenia pruniformis Cambess. is an endemic species from Brazilian Atlantic Forest. Essential oils from leaves and fruits from this species were obtained by hydrodistillation and analyzed by GCMS/CG-FID. In all, 25 compounds were identified, with predominance of sesquiterpene hydrocarbons in both plant parts. The major compounds were β-caryophyllene, bicyclogermacrene, germacrene D, δ- cadinene and α-copaene. Antioxidant activity was performed for essential oil from leaves using ORAC method, s...

  3. Distinguishing Vaccinium species by chemical fingerprinting based on NMR spectra, validated with spectra collected in different laboratories.

    Science.gov (United States)

    Markus, Michelle A; Ferrier, Jonathan; Luchsinger, Sarah M; Yuk, Jimmy; Cuerrier, Alain; Balick, Michael J; Hicks, Joshua M; Killday, K Brian; Kirby, Christopher W; Berrue, Fabrice; Kerr, Russell G; Knagge, Kevin; Gödecke, Tanja; Ramirez, Benjamin E; Lankin, David C; Pauli, Guido F; Burton, Ian; Karakach, Tobias K; Arnason, John T; Colson, Kimberly L

    2014-06-01

    A method was developed to distinguish Vaccinium species based on leaf extracts using nuclear magnetic resonance spectroscopy. Reference spectra were measured on leaf extracts from several species, including lowbush blueberry (Vaccinium angustifolium), oval leaf huckleberry (Vaccinium ovalifolium), and cranberry (Vaccinium macrocarpon). Using principal component analysis, these leaf extracts were resolved in the scores plot. Analysis of variance statistical tests demonstrated that the three groups differ significantly on PC2, establishing that the three species can be distinguished by nuclear magnetic resonance. Soft independent modeling of class analogies models for each species also showed discrimination between species. To demonstrate the robustness of nuclear magnetic resonance spectroscopy for botanical identification, spectra of a sample of lowbush blueberry leaf extract were measured at five different sites, with different field strengths (600 versus 700 MHz), different probe types (cryogenic versus room temperature probes), different sample diameters (1.7 mm versus 5 mm), and different consoles (Avance I versus Avance III). Each laboratory independently demonstrated the linearity of their NMR measurements by acquiring a standard curve for chlorogenic acid (R(2) = 0.9782 to 0.9998). Spectra acquired on different spectrometers at different sites classifed into the expected group for the Vaccinium spp., confirming the utility of the method to distinguish Vaccinium species and demonstrating nuclear magnetic resonance fingerprinting for material validation of a natural health product. Georg Thieme Verlag KG Stuttgart · New York.

  4. Chemical characterization of organic aerosol above a mid-latitude forest reveals a complex mixture of highly-functionalized chemical species and diverse structural features with temporal variability

    Science.gov (United States)

    Gentner, D. R.; Ditto, J.; Barnes, E.; Khare, P.

    2017-12-01

    Highly-functionalized organic compounds are known to be a major component of the complex mixture of the particle-phase compounds that comprise organic aerosol, yet little is known about the identity of many of these compounds, and their formation pathways and roles in atmospheric processes are poorly understood. We present results from the comprehensive chemical speciation of PM10 organic aerosols collected in July 2016 at the remote mid-latitude forest field site during PROPHET. Samples were analyzed via liquid and gas chromatography coupled with a quadrupole time-of-flight tandem mass spectrometry (MS×MS) following electrospray ionization (ESI) and atmospheric pressure chemical ionization (APCI). 8 hr samples were collected during day- and night-time sampling periods rather than more typical 24-hour samples. This analysis of the organic aerosol yielded over 12,000 unique compounds for which we have high accuracy molecular masses, formulas, and additional information on structural features using MS×MS. O:C ratios were 0.3 on average, yet the top 10% of compounds ranged 0.7-2.3. 70% and 69% of day- and night-time samples were nitrogen-containing, whereas 26% and 24% contained sulfur, respectively. Within these broader molecular categories, we observed a wide variety of molecular features that reveal a diversity of functional groups and moieties. In this presentation, we present the results of our speciation, temporal variability, connections to air parcel back trajectories and other bulk properties, and potential formation pathways.

  5. Chemical equilibrium. [maximizing entropy of gas system to derive relations between thermodynamic variables

    Science.gov (United States)

    1976-01-01

    The entropy of a gas system with the number of particles subject to external control is maximized to derive relations between the thermodynamic variables that obtain at equilibrium. These relations are described in terms of the chemical potential, defined as equivalent partial derivatives of entropy, energy, enthalpy, free energy, or free enthalpy. At equilibrium, the change in total chemical potential must vanish. This fact is used to derive the equilibrium constants for chemical reactions in terms of the partition functions of the species involved in the reaction. Thus the equilibrium constants can be determined accurately, just as other thermodynamic properties, from a knowledge of the energy levels and degeneracies for the gas species involved. These equilibrium constants permit one to calculate the equilibrium concentrations or partial pressures of chemically reacting species that occur in gas mixtures at any given condition of pressure and temperature or volume and temperature.

  6. Nb3Sn dipole magnet reacted after winding

    International Nuclear Information System (INIS)

    Taylor, C.; Scanlan, R.; Peters, C.; Wolgast, R.; Gilbert, W.; Hassenzahl, W.; Meuser, R.; Rechen, J.

    1984-09-01

    A 5 cm bore dia., 1-m-long dipole model magnet was constructed by winding un-reacted cable, followed by reaction and epoxy-impregnation. Experience and test results are described on the 1.7 mm dia. internal-tin wire, the eleven-strand flattened cable, fiberglass insulation, and construction of the magnet. Each half of the magnet has two double-pancake-type windings that were reacted in a single operation. The two double-pancakes were then separately vacuum impregnated after soldering the flexible Nb-Ti leads to the Nb 3 Sn conductors. No iron flux return yoke was used. In initial tests a central field of 8.0 T was reached at 4.4 K. However, evidence from training behavior, and 1.8 K tests indicate that premature quenching, rather than critical current of the cable, limited the field intensity. The magnet was reassembled and more rigidly clamped; additional test results are reported

  7. Effects of continuum breakdown on hypersonic aerothermodynamics for reacting flow

    Science.gov (United States)

    Holman, Timothy D.; Boyd, Iain D.

    2011-02-01

    This study investigates the effects of continuum breakdown on the surface aerothermodynamic properties (pressure, stress, and heat transfer rate) of a sphere in a Mach 25 flow of reacting air in regimes varying from continuum to a rarefied gas. Results are generated using both continuum [computational fluid dynamics (CFD)] and particle [direct simulation Monte Carlo (DSMC)] approaches. The DSMC method utilizes a chemistry model that calculates the backward rates from an equilibrium constant. A preferential dissociation model is modified in the CFD method to better compare with the vibrationally favored dissociation model that is utilized in the DSMC method. Tests of these models are performed to confirm their validity and to compare the chemistry models in both numerical methods. This study examines the effect of reacting air flow on continuum breakdown and the surface properties of the sphere. As the global Knudsen number increases, the amount of continuum breakdown in the flow and on the surface increases. This increase in continuum breakdown significantly affects the surface properties, causing an increase in the differences between CFD and DSMC. Explanations are provided for the trends observed.

  8. Sticky tunes: how do people react to involuntary musical imagery?

    Directory of Open Access Journals (Sweden)

    Victoria J Williamson

    Full Text Available The vast majority of people experience involuntary musical imagery (INMI or 'earworms'; perceptions of spontaneous, repetitive musical sound in the absence of an external source. The majority of INMI episodes are not bothersome, while some cause disruption ranging from distraction to anxiety and distress. To date, little is known about how the majority of people react to INMI, in particular whether evaluation of the experience impacts on chosen response behaviours or if attempts at controlling INMI are successful or not. The present study classified 1046 reports of how people react to INMI episodes. Two laboratories in Finland and the UK conducted an identical qualitative analysis protocol on reports of INMI reactions and derived visual descriptive models of the outcomes using grounded theory techniques. Combined analysis carried out across the two studies confirmed that many INMI episodes were considered neutral or pleasant, with passive acceptance and enjoyment being among the most popular response behaviours. A significant number of people, however, reported on attempts to cope with unwanted INMI. The most popular and effective behaviours in response to INMI were seeking out the tune in question, and musical or verbal distraction. The outcomes of this study contribute to our understanding of the aetiology of INMI, in particular within the framework of memory theory, and present testable hypotheses for future research on successful INMI coping strategies.

  9. Sticky Tunes: How Do People React to Involuntary Musical Imagery?

    Science.gov (United States)

    Williamson, Victoria J.; Liikkanen, Lassi A.; Jakubowski, Kelly; Stewart, Lauren

    2014-01-01

    The vast majority of people experience involuntary musical imagery (INMI) or ‘earworms’; perceptions of spontaneous, repetitive musical sound in the absence of an external source. The majority of INMI episodes are not bothersome, while some cause disruption ranging from distraction to anxiety and distress. To date, little is known about how the majority of people react to INMI, in particular whether evaluation of the experience impacts on chosen response behaviours or if attempts at controlling INMI are successful or not. The present study classified 1046 reports of how people react to INMI episodes. Two laboratories in Finland and the UK conducted an identical qualitative analysis protocol on reports of INMI reactions and derived visual descriptive models of the outcomes using grounded theory techniques. Combined analysis carried out across the two studies confirmed that many INMI episodes were considered neutral or pleasant, with passive acceptance and enjoyment being among the most popular response behaviours. A significant number of people, however, reported on attempts to cope with unwanted INMI. The most popular and effective behaviours in response to INMI were seeking out the tune in question, and musical or verbal distraction. The outcomes of this study contribute to our understanding of the aetiology of INMI, in particular within the framework of memory theory, and present testable hypotheses for future research on successful INMI coping strategies. PMID:24497938

  10. Lean premixed reacting flows with swirl and wall-separation zones in a contracting chamber

    Science.gov (United States)

    Zhang, Yuxin; Rusak, Zvi; Wang, Shixiao

    2017-11-01

    Low Mach number lean premixed reacting swirling flows with wall-separation zones in a contracting circular finite-length open chamber are studied. Assuming a complete reaction with high activation energy and chemical equilibrium behind the reaction zone, a nonlinear partial differential equation is derived for the solution of the flow stream function behind the reaction zone in terms of the inlet total enthalpy for a reacting flow, specific entropy and the circulation functions. Bifurcation diagrams of steady flows are described as the inlet swirl level is increased at fixed chamber contraction and reaction heat release. The approach is applied to an inlet solid-body rotation flow with constant profiles of the axial velocity, temperature and mixture reactant mass fraction. The computed results provide predictions of the critical inlet swirl levels for the first appearance of wall-separation states and for the size of the separation zone as a function of the inlet swirl ratio, Mach number, chamber contraction and heat release of the reaction. The methodology developed in this paper provides a theoretical feasibility for the development of the technology of swirl-assisted combustion where the reaction zone is supported and stabilized by a wall-separation zone.

  11. Efficient removal of sulfur hexafluoride (SF6) through reacting with recycled electroplating sludge.

    Science.gov (United States)

    Zhang, Jia; Zhou, Ji Zhi; Liu, Qiang; Qian, Guangren; Xu, Zhi Ping

    2013-06-18

    This paper reports that recycled electroplating sludge is able to efficiently remove greenhouse gas sulfur hexafluoride (SF6). The removal process involves various reactions of SF6 with the recycled sludge. Remarkably, the sludge completely removed SF6 at a capacity of 1.10 mmol/g (SF6/sludge) at 600 °C. More importantly, the evolved gases were SO2, SiF4, and a limited amount of HF, with no toxic SOF4, SO2F2, or SF4 being detected. These generated gases can be readily captured and removed by NaOH solution. The reacted solids were further found to be various metal fluorides, thus revealing that SF6 removal takes place by reacting with various metal oxides and silicate in the sludge. Moreover, the kinetic investigation revealed that the SF6 reaction with the sludge is a first-order chemically controlled process. This research thus demonstrates that the waste electroplating sludge can be potentially used as an effective removal agent for one of the notorious greenhouse gases, SF6.

  12. Comparison of the chemical composition of three species of smartweed (genus Persicaria) with a focus on drimane sesquiterpenoids.

    Science.gov (United States)

    Prota, N; Mumm, R; Bouwmeester, H J; Jongsma, M A

    2014-12-01

    The genus Persicaria is known to include species accumulating drimane sesquiterpenoids, but a comparative analysis highlighting the compositional differences has not been done. In this study, the secondary metabolites of both flowers and leaves of Persicariahydropiper, Persicariamaculosa and Persicariaminor, three species which occur in the same habitat, were compared. Using gas chromatography-mass spectrometry (GC-MS) analysis of extracts, overall 21/29 identified compounds in extracts were sesquiterpenoids and 5/29 were drimanes. Polygodial was detected in all species, though not in every sample of P. maculosa. On average, P. hydropiper flowers contained about 6.2 mg g FW(-1) of polygodial, but P. minor flowers had 200-fold, and P. maculosa 100,000 fold lower concentrations. Comparatively, also other sesquiterpenes were much lower in those species, suggesting the fitness benefit to depend on either investing a lot or not at all in terpenoid-based secondary defences. For P. hydropiper, effects of flower and leaf development and headspace volatiles were analysed as well. The flower stage immediately after fertilisation was the one with the highest content of drimane sesquiterpenoids and leaves contained about 10-fold less of these compounds compared to flowers. The headspace of P. hydropiper contained 8 compounds: one monoterpene, one alkyl aldehyde and six sesquiterpenes, but none were drimanes. The potential ecological significance of the presence or absence of drimane sesquiterpenoids and other metabolites for these plant species are discussed. Copyright © 2014 Elsevier Ltd. All rights reserved.

  13. Non-equilibrium reaction rates in chemical kinetic equations

    Science.gov (United States)

    Gorbachev, Yuriy

    2018-05-01

    Within the recently proposed asymptotic method for solving the Boltzmann equation for chemically reacting gas mixture, the chemical kinetic equations has been derived. Corresponding one-temperature non-equilibrium reaction rates are expressed in terms of specific heat capacities of the species participate in the chemical reactions, bracket integrals connected with the internal energy transfer in inelastic non-reactive collisions and energy transfer coefficients. Reactions of dissociation/recombination of homonuclear and heteronuclear diatomic molecules are considered. It is shown that all reaction rates are the complex functions of the species densities, similarly to the unimolecular reaction rates. For determining the rate coefficients it is recommended to tabulate corresponding bracket integrals, additionally to the equilibrium rate constants. Correlation of the obtained results with the irreversible thermodynamics is established.

  14. Large eddy simulation and direct numerical simulation of high speed turbulent reacting flows

    Science.gov (United States)

    Adumitroaie, V.; Frankel, S. H.; Madnia, C. K.; Givi, P.

    The objective of this research is to make use of Large Eddy Simulation (LES) and Direct Numerical Simulation (DNS) for the computational analyses of high speed reacting flows. Our efforts in the first phase of this research conducted within the past three years have been directed in several issues pertaining to intricate physics of turbulent reacting flows. In our previous 5 semi-annual reports submitted to NASA LaRC, as well as several technical papers in archival journals, the results of our investigations have been fully described. In this progress report which is different in format as compared to our previous documents, we focus only on the issue of LES. The reason for doing so is that LES is the primary issue of interest to our Technical Monitor and that our other findings were needed to support the activities conducted under this prime issue. The outcomes of our related investigations, nevertheless, are included in the appendices accompanying this report. The relevance of the materials in these appendices are, therefore, discussed only briefly within the body of the report. Here, results are presented of a priori and a posterior analyses for validity assessments of assumed Probability Density Function (PDF) methods as potential subgrid scale (SGS) closures for LES of turbulent reacting flows. Simple non-premixed reacting systems involving an isothermal reaction of the type A + B yields Products under both chemical equilibrium and non-equilibrium conditions are considered. A priori analyses are conducted of a homogeneous box flow, and a spatially developing planar mixing layer to investigate the performance of the Pearson Family of PDF's as SGS models. A posteriori analyses are conducted of the mixing layer using a hybrid one-equation Smagorinsky/PDF SGS closure. The Smagorinsky closure augmented by the solution of the subgrid turbulent kinetic energy (TKE) equation is employed to account for hydrodynamic fluctuations, and the PDF is employed for modeling the

  15. Chemical Composition and in-Vitro Evaluation of the Antimicrobial and Antioxidant Activities of Essential Oils Extracted from Seven Eucalyptus Species

    Directory of Open Access Journals (Sweden)

    Abdul Ghaffar

    2015-11-01

    Full Text Available Eucalyptus is well reputed for its use as medicinal plant around the globe. The present study was planned to evaluate chemical composition, antimicrobial and antioxidant activity of the essential oils (EOs extracted from seven Eucalyptus species frequently found in South East Asia (Pakistan. EOs from Eucalyptus citriodora, Eucalyptus melanophloia, Eucalyptus crebra, Eucalyptus tereticornis, Eucalyptus globulus, Eucalyptus camaldulensis and Eucalyptus microtheca were extracted from leaves through hydrodistillation. The chemical composition of the EOs was determined through GC-MS-FID analysis. The study revealed presence of 31 compounds in E. citriodora and E. melanophloia, 27 compounds in E. crebra, 24 compounds in E. tereticornis, 10 compounds in E. globulus, 13 compounds in E. camaldulensis and 12 compounds in E. microtheca. 1,8-Cineole (56.5%, α-pinene (31.4%, citrinyl acetate (13.3%, eugenol (11.8% and terpenene-4-ol (10.2% were the highest principal components in these EOs. E. citriodora exhibited the highest antimicrobial activity against the five microbial species tested (Staphylococcus aureus, Bacillus subtilis, Escherichia coli, Aspergillus niger and Rhizopus solani. Gram positive bacteria were found more sensitive than Gram negative bacteria to all EOs. The diphenyl-1-picrylhydazyl (DPPH radical scavenging activity and percentage inhibition of linoleic acid oxidation were highest in E. citriodora (82.1% and 83.8%, respectively followed by E. camaldulensis (81.9% and 83.3%, respectively. The great variation in chemical composition of EOs from Eucalyptus, highlight its potential for medicinal and nutraceutical applications.

  16. Chemical Composition and in-Vitro Evaluation of the Antimicrobial and Antioxidant Activities of Essential Oils Extracted from Seven Eucalyptus Species.

    Science.gov (United States)

    Ghaffar, Abdul; Yameen, Muhammad; Kiran, Shumaila; Kamal, Shagufta; Jalal, Fatima; Munir, Bushra; Saleem, Sadaf; Rafiq, Naila; Ahmad, Aftab; Saba, Iram; Jabbar, Abdul

    2015-11-18

    Eucalyptus is well reputed for its use as medicinal plant around the globe. The present study was planned to evaluate chemical composition, antimicrobial and antioxidant activity of the essential oils (EOs) extracted from seven Eucalyptus species frequently found in South East Asia (Pakistan). EOs from Eucalyptus citriodora, Eucalyptus melanophloia, Eucalyptus crebra, Eucalyptus tereticornis, Eucalyptus globulus, Eucalyptus camaldulensis and Eucalyptus microtheca were extracted from leaves through hydrodistillation. The chemical composition of the EOs was determined through GC-MS-FID analysis. The study revealed presence of 31 compounds in E. citriodora and E. melanophloia, 27 compounds in E. crebra, 24 compounds in E. tereticornis, 10 compounds in E. globulus, 13 compounds in E. camaldulensis and 12 compounds in E. microtheca. 1,8-Cineole (56.5%), α-pinene (31.4%), citrinyl acetate (13.3%), eugenol (11.8%) and terpenene-4-ol (10.2%) were the highest principal components in these EOs. E. citriodora exhibited the highest antimicrobial activity against the five microbial species tested (Staphylococcus aureus, Bacillus subtilis, Escherichia coli, Aspergillus niger and Rhizopus solani). Gram positive bacteria were found more sensitive than Gram negative bacteria to all EOs. The diphenyl-1-picrylhydazyl (DPPH) radical scavenging activity and percentage inhibition of linoleic acid oxidation were highest in E. citriodora (82.1% and 83.8%, respectively) followed by E. camaldulensis (81.9% and 83.3%, respectively). The great variation in chemical composition of EOs from Eucalyptus, highlight its potential for medicinal and nutraceutical applications.

  17. Induction of molecular endpoints by reactive oxygen species in human lung cells predicted by physical chemical properties of engineered nanoparticles

    Science.gov (United States)

    A series of six titanium dioxide and two cerium oxide engineered nanomaterials were assessed for their ability to induce cytotoxicity, reactive oxygen species (ROS), and various types of DNA and protein damage in human respiratory BEAS-2B cells exposed in vitro for 72 hours at se...

  18. Cumulative Index to Chemicals and to Common and Scientific Names of Species Listed in Contaminant Hazard Reviews 1 Through 34.

    Science.gov (United States)

    1999-03-01

    Wildlife Research Center- synthesizes ecotoxicological data for selected environmental contaminants, with emphasis on hazards to native species of flora...series-—sponsored by the U.S. Geological Survey Patuxent Wildlife Research Center—synthesizes ecotoxicological data for selected environmental...7 37. Macronectes giganteus: 32 16; 33 26; 34 27. Macrophytes , aquatic, Cabomba spp., Chara sp., Elodea, Lemna, Myriophyllum, Polygonum sp

  19. Phylogenetic and chemical studies in the potential psychotropic species complex of Psilocybe atrobrunnea with taxonomic and nomenclatural notes

    NARCIS (Netherlands)

    Borovička, J.; Oborník, M.; Stříbrný, J.; Noordeloos, M.E.; Parra Sánchez, L.A.; Gryndler, M.

    2015-01-01

    Five Psilocybe species with unresolved systematic position (P. atrobrunnea, P. laetissima, P. medullosa, P. pelliculosa, and P. silvatica) were investigated using four molecular markers (EF1-α, ITS, LSU, and IGS). Phylogenetic analysis revealed that with the exception of P. laetissima, which is now

  20. Chemical composition and fumigant toxicity of the essential oils from 16 species of Eucalyptus against Haematobia irritans (Diptera: Muscidae) adults

    OpenAIRE

    Juan, Laura W.; Lucía Mulas, Alejandro; Zerba, Eduardo N.; Harrand, Leonel; Marco, Martín; Masuh, Hector M.

    2011-01-01

    Oils extracted from various species of Eucalyptus (Eucalyptus badjensis Beuzev & Welch, Eucalyptus badjensis x Eucalyptus nitens, Eucalyptus benthamii variety dorrigoensis Maiden & Cambage, Eucalyptus botryoides Smith, Eucalyptus dalrympleana Maiden, Eucalyptus fastigata Deane & Maiden, Eucalyptus nobilis L.A.S. Johnson & K. D. Hill, Eucalyptus polybractea R. Baker, Eucalyptus radiata ssp. radiata Sieber ex Spreng, Eucalyptus resinifera Smith, Eucalyptus robertsonii Blakely, Eucalyptus rubida...

  1. Effect of seed treatments on the chemical composition and properties of two amaranth species: starch and protein

    NARCIS (Netherlands)

    Gamel, T.H.; Linssen, J.P.H.; Mesallem, A.S.; Damir, A.A.; Shekib, L.A.

    2005-01-01

    The seeds of two Amaranth species were studied. The starch contents were 543 and 623 g kg-1 while crude protein contents were 154 and 169 g kg-1 for Amaranthus caudatus and Amaranthus cruentus seeds, respectively. The effect of several treatments, including cooking, popping and germination and flour

  2. ENVIRONMENT: a computational platform to stochastically simulate reacting and self-reproducing lipid compartments

    Science.gov (United States)

    Mavelli, Fabio; Ruiz-Mirazo, Kepa

    2010-09-01

    'ENVIRONMENT' is a computational platform that has been developed in the last few years with the aim to simulate stochastically the dynamics and stability of chemically reacting protocellular systems. Here we present and describe some of its main features, showing how the stochastic kinetics approach can be applied to study the time evolution of reaction networks in heterogeneous conditions, particularly when supramolecular lipid structures (micelles, vesicles, etc) coexist with aqueous domains. These conditions are of special relevance to understand the origins of cellular, self-reproducing compartments, in the context of prebiotic chemistry and evolution. We contrast our simulation results with real lab experiments, with the aim to bring together theoretical and experimental research on protocell and minimal artificial cell systems.

  3. Chemical properties and reactive oxygen and nitrogen species quenching activities of dry sugar-amino acid maillard reaction mixtures exposed to baking temperatures.

    Science.gov (United States)

    Chen, Xiu-Min; Liang, Ningjian; Kitts, David D

    2015-10-01

    Maillard reaction products (MRPs) derived from 10 different, dry sugar-amino acid reaction model systems were examined for changes in color index (E), sugar loss, and formation of α-dicarbonyl compounds; the changes were correlated with relative activities to quench both reactive oxygen (ROS) and reactive nitrogen (RNS) species. Reducing sugars, xylose, ribose, fructose, glucose, and non-reducing sucrose were reacted with glycine (Xyl-Gly, Rib-Gly, Fru-Gly, Glc-Gly, and Suc-Gly), or lysine (Xyl-Lys, Rib-Lys, Fru-Lys, Glc-Lys, and Suc-Lys), respectively, at temperatures of 150°C and 180°C for time periods ranging from 5 to 60min. ROS quenching capacity was negatively correlated with color index (E) (r=-0.604, P<0.001), and positively correlated with sugar loss (r=0.567, P<0.001). MRPs also exhibited activity to quench RNS as assessed by nitric oxide (NO) inhibition in differentiated Caco-2 cells that were induced with interferon-γ (IFN-γ) and phorbol ester (PMA) cocktail. We also showed a correlation between RNS and color index, sugar loss, and ROS quenching activities for MR mixtures that were heated for a short time (e.g. 10min) at 150°C. MRP quenching of ROS was largely influenced by sugar type, whereas, RNS quenching was dependent more so on the interaction between reactants and reaction conditions used to generate MRPs. Copyright © 2015 Elsevier Ltd. All rights reserved.

  4. Comparison of chemical profiles between the root and aerial parts from three Bupleurum species based on a UHPLC-QTOF-MS metabolomics approach.

    Science.gov (United States)

    Zhu, Lin; Liang, Zhi-Tao; Yi, Tao; Ma, Yue; Zhao, Zhong-Zhen; Guo, Bao-Lin; Zhang, Jian-Ye; Chen, Hu-Biao

    2017-06-12

    Bupleuri Radix (Chaihu) represents one of the most successful and widely used herbal medicines in Asia for the treatment of many diseases such as inflammatory disorders and infectious diseases over the past 2000 years. In the Chinese Pharmacopoeia, Chaihu is recorded as the dried roots of Bupleurum chinense DC. and B. scorzonerifolium Willd. (Umbelliferae). However, the widespread demand for the herb has tended to far outstrip the supply. Whether the aerial parts, which account for 70 ~ 85% of the dry weights of Bupleurum species, could be used as an alternative for the root has become an important scientific issue for the sustainable utilization of Bupleurum species. On the other hand, in some areas including the southeast of China as well as in Spain, the aerial parts of Bupleurum species have already been used in the folk medications. Therefore, to clarify whether the root and aerial parts of Bupleurum species are "equivalent" in the types and quantities of chemical constituents which subsequently influence their biological activities and therapeutic effects is of great importance for both the rational and sustainable use of this herb. In the present study, the chemical profiles between the root and aerial parts of Bupleurum species from different species and collected from various locations were analyzed and compared by the ultra-high performance liquid chromatography quadrupole/time of flight-mass spectrometry (UHPLC-QTOF-MS). A total of 56 peaks were identified in the root and/or aerial parts from different batches of Bupleurum species, by comparison of references standards or with those reported in the literature. Principal Component Analysis (PCA) was conducted for displaying the differentiating clustering between these two parts. The results disclosed the distinct variations between them, which indicated that the aerial parts could not be used as an alternative of root from a chemodiversity perspective. The differentiating markers resulted from the PCA

  5. Modeling response of species to microcontaminants: comparative ecotoxicology by (sub)lethal body burdens as a function of species size and partition ratio of chemicals.

    Science.gov (United States)

    Hendriks, A J

    1995-11-01

    -term versus long-term, lethal versus sublethal, and median versus no response concentration ratios each contributed factors of about 2-3 to this overall ratio. The model for internal concentrations indicated that the ratio between the short-term and the long-term LC50 will be high for large species and high octanol-water partition ratios.

  6. Vorticity Dynamics in Single and Multiple Swirling Reacting Jets

    Science.gov (United States)

    Smith, Travis; Aguilar, Michael; Emerson, Benjamin; Noble, David; Lieuwen, Tim

    2015-11-01

    This presentation describes an analysis of the unsteady flow structures in two multinozzle swirling jet configurations. This work is motivated by the problem of combustion instabilities in premixed flames, a major concern in the development of modern low NOx combustors. The objective is to compare the unsteady flow structures in these two configurations for two separate geometries and determine how certain parameters, primarily distance between jets, influence the flow dynamics. The analysis aims to differentiate between the flow dynamics of single nozzle and triple nozzle configurations. This study looks at how the vorticity in the shear layers of one reacting swirling jet can affect the dynamics of a nearby similar jet. The distance between the swirling jets is found to have an effect on the flow field in determining where swirling jets merge and on the dynamics upstream of the merging location. Graduate Student, School of Aerospace Engineering, Georgia Institute of Technology, Atlanta, GA.

  7. Optimal stretching in the reacting wake of a bluff body.

    Science.gov (United States)

    Wang, Jinge; Tithof, Jeffrey; Nevins, Thomas D; Colón, Rony O; Kelley, Douglas H

    2017-12-01

    We experimentally study spreading of the Belousov-Zhabotinsky reaction behind a bluff body in a laminar flow. Locations of reacted regions (i.e., regions with high product concentration) correlate with a moderate range of Lagrangian stretching and that range is close to the range of optimal stretching previously observed in topologically different flows [T. D. Nevins and D. H. Kelley, Phys. Rev. Lett. 117, 164502 (2016)]. The previous work found optimal stretching in a closed, vortex dominated flow, but this article uses an open flow and only a small area of appreciable vorticity. We hypothesize that optimal stretching is common in advection-reaction-diffusion systems with an excitation threshold, including excitable and bistable systems, and that the optimal range depends on reaction chemistry and not on flow shape or characteristic speed. Our results may also give insight into plankton blooms behind islands in ocean currents.

  8. REAC/TS Radiation Accident Registry: An Overview

    Energy Technology Data Exchange (ETDEWEB)

    Doran M. Christensen, DO, REAC/TS Associate Director and Staff Physician Becky Murdock, REAC/TS Registry and Health Physics Technician

    2012-12-12

    Over the past four years, REAC/TS has presented a number of case reports from its Radiation Accident Registry. Victims of radiological or nuclear incidents must meet certain dose criteria for an incident to be categorized as an “accident” and be included in the registry. Although the greatest numbers of “accidents” in the United States that have been entered into the registry involve radiation devices, the greater percentage of serious accidents have involved sealed sources of one kind or another. But if one looks at the kinds of accident scenarios that have resulted in extreme consequence, i.e., death, the greater share of deaths has occurred in medical settings.

  9. LES-ODT Simulations of Turbulent Reacting Shear Layers

    Science.gov (United States)

    Hoffie, Andreas; Echekki, Tarek

    2012-11-01

    Large-eddy simulations (LES) combined with the one-dimensional turbulence (ODT) simulations of a spatially developing turbulent reacting shear layer with heat release and high Reynolds numbers were conducted and compared to results from direct numerical simulations (DNS) of the same configuration. The LES-ODT approach is based on LES solutions for momentum on a coarse grid and solutions for momentum and reactive scalars on a fine ODT grid, which is embedded in the LES computational domain. The shear layer is simulated with a single-step, second-order reaction with an Arrhenius reaction rate. The transport equations are solved using a low Mach number approximation. The LES-ODT simulations yield reasonably accurate predictions of turbulence and passive/reactive scalars' statistics compared to DNS results.

  10. How preschoolers react to norm violations is associated with culture.

    Science.gov (United States)

    Gampe, Anja; Daum, Moritz M

    2018-01-01

    Children from the age of 3years understand social norms as such and enforce these norms in interactions with others. Differences in parental and institutional education across cultures make it likely that children receive divergent information about how to act in cases of norm violations. In the current study, we investigated whether cultural values are associated with the ways in which children react to norm violations. We tested 80 bicultural 3-year-olds with a norm enforcement paradigm and analyzed their reactions to norm violations. The reactions were correlated to the children's parental cultural values using the Global Leadership and Organizational Behavior Effectiveness (GLOBE) scales, and these results show that parental culture was associated with children's reactions to norm violations. The three strongest correlations were found for institutional collectivism, performance orientation, and assertiveness. Copyright © 2017 Elsevier Inc. All rights reserved.

  11. Electrochemical corrosion studies on a selected carbon steel for application in nuclear waste disposal containers: Influence of chemical species in brines on corrosion

    International Nuclear Information System (INIS)

    Farvaque-Bera, A.M.; Smailos, E.

    1994-04-01

    In previous corrosion studies, carbon steels were identified as promising materials for the manufacture of long-lived high-level waste containers that could act as an engineered barrier in a rock-salt repository. In this paper, the influence of chemical species, potentially present in salt brines, on the electrochemical corrosion behavior of the preselected fine-grained steel TStE 355 was studied. The steel was examined at 90 C in a disposal relevant NaCl-rich brine containing various species (Br - , I - , Cu 2+ , Mn 2+ , S 2- , B(OH )4 - and Fe 3+ ) at concentrations between 10 -5 M/I and 10 -1 M/I. (orig.) [de

  12. Essential Oils of Myrtaceae Species Growing Wild in Tunisia: Chemical Variability and Antifungal Activity Against Biscogniauxia mediterranea, the Causative Agent of Charcoal Canker.

    Science.gov (United States)

    Yangui, Islem; Zouaoui Boutiti, Meriem; Boussaid, Mohamed; Messaoud, Chokri

    2017-07-01

    The chemical composition of five Eucalyptus species and five Myrtus communis L. populations was investigated using GC/MS and GC-FID. For Eucalyptus essential oils, 32 compounds, representing 88.56 - 96.83% of the total oil according to species, were identified. The main compounds were 1,8-cineole, α-pinene, p-cymene, γ-gurjunene, α-aromadendrene, and β-phellandrene. For Myrtle essential oils, 26 compounds, representing 93.13 - 98.91% of the total oil were identified. α-Pinene, 1,8-cineole, linalool, and myrtenyl acetate were found to be the major compounds. Principal component analysis (PCA) showed chemical differentiation between Eucalyptus species and between Myrtle populations. Biscogniauxia mediterranea, the causative agent of charcoal canker, was identified according to its morphological and molecular characteristics. Essential oils of the investigated Eucalyptus species and Myrtle populations were tested for their antifungal capacity against this fungus. The antifungal activity varied according to the essential oil composition. Biscogniauxia mediterranea exhibited powerful resistance to some essential oils including them of Eucalyptus lehmannii and Eucalyptus sideroxylon but it was very sensitive to Eucalyptus camaldulensis oil (IC 50  = 3.83 mg/ml) and M. communis oil from Zaghouan (IC 50  = 1 mg/ml). This sensitivity was found to be correlated to some essential oil compounds such as p-cymene, carvacrol, cuminaldehyde, and linalool. © 2017 Wiley-VHCA AG, Zurich, Switzerland.

  13. CHEMICAL COMPOSITION, IN VITRO RUMEN FERMENTATION, AND DIGESTIBILITY OF SELECTED BROWSE SPECIES BY BUFFALOES (Bubalus bubalis L. AT A SEMI-DECIDUOUS FOREST IN VENEZUELA

    Directory of Open Access Journals (Sweden)

    Álvaro José Ojeda

    2013-01-01

    Full Text Available To determine the chemical composition and nutritive value of selected browse species by buffaloes (Bubalus bubalis L. in a silvopastoral system at a semi-deciduous tropical forest (SDTF, epidermal fragments in fecal samples from 14 males of Murrah breed were evaluated. The animals grazed for 91 days in 85 ha located in Portuguesa State, Venezuela, of which 35 ha corresponded to natural grass pastures (969.3 ± 28.6 kg DM ha-1, and the rest to SDTF with 463 plant ha-1. Eleven botanical families and 22 species were identified, 40.9% belonged to the Fabaceae family. The specie Guazuma ulmifolia (Sterculiaceae had the highest relative dominancy (60.4% and an Importance Value Index of 162.6. 60.4% of epidermal fragments corresponded to herbaceous Poaceae, and the rest was distributed among five different species, with the highest occurrence (94.6% for Samanea saman and Sida acuta. There were differences (P

  14. Fungal decay resistance of wood reacted with phosphorus pentoxide-amine system

    Science.gov (United States)

    Hong-Lin Lee; George C. Chen; Roger M. Rowell

    2004-01-01

    Resistance of wood reacted in situ with phosphorus pentoxide-amine to the brown-rot fungus Gloeophyllum trabeum and white-rot fungus Trametes versicolor was examined. Wood reacted with either octyl, tribromo, or nitro derivatives were more resistant to both fungi. Threshold retention values of phosphoramide-reacted wood to white-rot fungus T. versicolor ranged from 2.9...

  15. Chemical analysis and antioxidant activity of the essential oils of three Piperaceae species growing in the central region of Cuba.

    Science.gov (United States)

    Rodríguez, Elisa Jorge; Saucedo-Hernández, Yanelis; Vander Heyden, Yvan; Simó-Alfonso, Ernesto F; Ramis-Ramos, Guillermo; Lerma-García, María Jesús; Monteagudo, Urbano; Bravo, Luis; Medinilla, Mildred; de Armas, Yuriam; Herrero-Martínez, José Manuel

    2013-09-01

    The present study describes the phytochemical profile and antioxidant activity of the essential oils of three Piperaceae species collected in the central region of Cuba. The essential oils of Piper aduncum, P. auritum and P. umbellatum leaves, obtained by hydrodistillation, were analyzed by gas chromatography-mass spectrometry. The main components of P. aduncum oil were piperitone (34%), camphor (17.1%), camphene (10.9%), 1,8-cineol (8.7%) and viridiflorol (7.4%), whereas that of P. auritum and P. umbellatum was safrole (71.8 and 26.4%, respectively). The antioxidant properties of the essential oils were also evaluated using several assays for radical scavenging ability (DPPH test and reducing power) and inhibition of lipid oxidation (ferric thiocyanate method and evaluation against Cucurbita seed oil by peroxide, thiobarbituric acid and p-anisidine methods). P. auritum showed the strongest antioxidant activity among the Piper species investigated, but lower than those of butylated hydroxyanisol and propyl gallate.

  16. Nitrogen complex species and its chemical nature in TiO2 for visible-light sensitized photocatalysis

    International Nuclear Information System (INIS)

    Asahi, Ryoji; Morikawa, Takeshi

    2007-01-01

    A photocatalyst with high reactivity under visible-light has been desired to utilize solar irradiation or interior lighting efficiently. Nitrogen-doped TiO 2 revealed significant improvement in optical absorption and photocatalytic activity over TiO 2 under visible light. We have performed the first-principles calculations to study the detailed N complex species introduced in TiO 2 . The results include stable geometries, densities of states, formation energies, and core levels. The present systematic studies account for the long-term controversial issue on N-doped TiO 2 , in particular, regarding the detailed assignment of N 1s binding energies observed in the XPS measurement. The detailed analyses of the formation energies show that introducing the N species more in a controlled way via process conditions is crucial to achieve the optimized photocatalytic performance

  17. Comparison of the Chemical Profiles and Antioxidant and Antidiabetic Activities of Extracts from Two Ganoderma Species (Agaricomycetes).

    Science.gov (United States)

    Tang, Xiaoqing; Cai, Weixi; Xu, Baojun

    2016-01-01

    The objective of this study was to compare the mycochemical profiles, antioxidant activities, and antidiabetic effects of 2 species of genus Ganoderma, the red lingzhi (G. lucidum) and purple lingzhi (G. sinense) mushrooms. In Chinese medicinal practice, hot water and ethanol are used as solvents to extract samples. In this study, a total of 4 extracts (ethanol and hot water extracts from G. lucidum and G. sinense) were prepared for further assays. Hot water extracts presented much higher values for total phenolic content and ferric-reducing antioxidant power than the ethanol extracts. Ethanol (70%) extract of G. lucidum had the strongest α-glycosidase inhibitory capacity, but the lingzhi polysaccharides showed no inhibitory effect. It also had the largest amount of total ganoderic acids. The results indicated that ethanol extracts from both G. lucidum and G. sinense showed better antidiabetic effects than the hot water extracts. Ganoderic acids, rather than polysaccharides, may contribute the antidiabetic effects of both the Ganoderma species.

  18. Chemical analysis of reactive species and antimicrobial activity of/nwater treated by nanosecond pulsed DBD air plasma

    Czech Academy of Sciences Publication Activity Database

    Laurita, R.; Barbieri, D.; Gherardi, M.; Colombo, V.; Lukeš, Petr

    2015-01-01

    Roč. 3, č. 2 (2015), s. 53-61 ISSN 2212-8166 R&D Projects: GA MŠk(CZ) LD14080 Grant - others:European Cooperation in Science and Technology(XE) COST TD1208 Institutional support: RVO:61389021 Keywords : Dielectric barrier discharge * Plasma activated water * Reactive species * Peroxynitrite * Phenol degradation * Candida albicans * Staphylococcus aureus * Antimicrobial activity * Nosocomial infections Subject RIV: BL - Plasma and Gas Discharge Physics http://www.sciencedirect.com/science/article/pii/S2212816615300081

  19. Floral nectary, nectar production dynamics and chemical composition in five nocturnal Oenothera species (Onagraceae) in relation to floral visitors.

    Science.gov (United States)

    Antoń, Sebastian; Komoń-Janczara, Elwira; Denisow, Bożena

    2017-12-01

    Main conclusion The floral nectars were sucrose-dominant; however, nectar protein and amino acid contents differed, indicating that composition of nitrogenous compounds may vary considerably even between closely related plant species, irrespectively of nectary structure. Numerous zoophilous plants attract their pollinators by offering floral nectar; an aqueous solution produced by specialized secretory tissues, known as floral nectaries. Although many papers on nectaries and nectar already exist, there has been a little research into the structure of nectaries and/or nectar production and composition in species belonging to the same genus. To redress this imbalance, we sought, in the present paper, to describe the floral nectary, nectar production, and nectar composition in five nocturnal Oenothera species with respect to their floral visitors. The structure of nectaries was similar for all the species investigated, and comprised the epidermis (with nectarostomata), numerous layers of nectary parenchyma, and subsecretory parenchyma. Anthesis for a single flower was short (ca. 10-12 h), and flowers lasted only one night. The release of floral nectar commenced at the bud stage (approx. 4 h before anthesis) and nectar was available to pollinators until petal closure. Nectar concentration was relatively low (ca. 27%) and the nectar was sucrose-dominant, and composed mainly of sucrose, glucose and fructose. The protein content of the nectar was also relatively low (on average, 0.31 µg ml -1 ). Nevertheless, a great variety of amino acids, including both protein and non-protein types, was detected in the nectar profile of the investigated taxa. We noted both diurnal and nocturnal generalist, opportunistic floral insect visitors.

  20. Chemical composition and antioxidant activities of essential oils and methanol extracts of three wild Lavandula L. species.

    Science.gov (United States)

    Messaoud, C; Chograni, H; Boussaid, M

    2012-11-01

    A comparative study of essential oil composition, polyphenol content and antioxidant activities of Lavandula coronopifolia, Lavandula multifida and Lavandula stoechas subsp. stoechas were reported. Qualitative and quantitative variations in the composition of oils according to species were shown. Lavandula coronopifolia's oil was characterised by high proportions of trans-β-ocimene (26.9%), carvacrol (18.5%), β-bisabolene (13.1%) and myrcene (7.5%). The main components of L. multifida oil are carvacrol (65.1%) and β-bisabolene (24.7%). Lavandula stoechas oil is rich in fenchone (34.3%) and comphor (27.4%). The total phenolic and flavonoid contents also significantly varied among species. Lavandula coronopifolia exhibits the highest phenolic and flavonoid contents (31.3 mg GAE g(-1) and 16.3 mg RE g(-1), respectively), followed by L. multifida (30.8 mg GAE g(-1) and 12.3 mg RE g(-1)). Methanolic extracts and essential oils displayed significant antioxidant activities. The level of antioxidant capacity varied according to extracts and species.

  1. Generation and Role of Reactive Oxygen and Nitrogen Species Induced by Plasma, Lasers, Chemical Agents, and Other Systems in Dentistry

    Science.gov (United States)

    Jha, Nayansi; Ryu, Jae Jun

    2017-01-01

    The generation of reactive oxygen and nitrogen species (RONS) has been found to occur during inflammatory procedures, during cell ischemia, and in various crucial developmental processes such as cell differentiation and along cell signaling pathways. The most common sources of intracellular RONS are the mitochondrial electron transport system, NADH oxidase, and cytochrome P450. In this review, we analyzed the extracellular and intracellular sources of reactive species, their cell signaling pathways, the mechanisms of action, and their positive and negative effects in the dental field. In dentistry, ROS can be found—in lasers, photosensitizers, bleaching agents, cold plasma, and even resin cements, all of which contribute to the generation and prevalence of ROS. Nonthermal plasma has been used as a source of ROS for biomedical applications and has the potential for use with dental stem cells as well. There are different types of dental stem cells, but their therapeutic use remains largely untapped, with the focus currently on only periodontal ligament stem cells. More research is necessary in this area, including studies about ROS mechanisms with dental cells, along with the utilization of reactive species in redox medicine. Such studies will help to provide successful treatment modalities for various diseases. PMID:29204250

  2. DETERMINING ACTIVE OXIDANT SPECIES REACTING WITH ORGANOPHOSPHATE PESTICIDES IN CHLORINATED DRINKING WATER

    Science.gov (United States)

    Chlorpyrifos (CP) is an organophosphate (OP) pesticide that was used as a model compound to investigate the transformation of OP pesticides at low pH and in the presence of bromide and natural organic matter (NOM) under drinking water treatment conditions. Raman spectroscopy was...

  3. Chemical composition and in vitro antimicrobial activity of the essential oils of two Helichrysum species from Tanzania.

    Science.gov (United States)

    Bougatsos, Christos; Ngassapa, Olipa; Runyoro, Deborah K B; Chinou, Ioanna B

    2004-01-01

    The chemical composition of the essential oils obtained from the aerial parts of Helichrysum cymosum and H. fulgidum, from Tanzania, were analyzed by GC and GC/MS. A total of sixty-five compounds, representing 92.4% and 88.2% of the two oils, respectively, were identified. trans-Caryophyllene, caryophyllene oxide, beta-pinene, p-cymene, spathulenol and beta-bourbonene were found to be the main components. Furthermore, the oils were tested against six gram (+/-) bacteria and three pathogenic fungi. It was found that the oil of H. fulgidum exhibited significant antimicrobial activity, while the oil of H. cymosum was not active at all.

  4. Spectroscopic studies of neutral and chemically oxidized species of β-carotene, lycopene and norbixin in CH2Cl2: Fluorescence from intermediate compounds

    International Nuclear Information System (INIS)

    Alwis, D.D.D.H; Chandrika, U.G.; Jayaweera, P.M.

    2015-01-01

    Radical cations, dications and oxidized intermediate species of three carotenoids, namely, β-carotene, lycopene and norbixin, were generated in CH 2 Cl 2 solutions via chemical oxidation using anhydrous FeCl 3 . UV–vis, fluorescence and fluorescence-excitation spectroscopic studies were performed to understand and compare the nature of intermediate species generated during the chemical oxidation process and subsequent degradation. The intense emission observed at 550 nm can be assigned to the S 2 →S 0 (1 1 B u →1 1 A g ) transition of the carotenoid molecules. The 350 nm excitation during the oxidation process for β-carotene, lycopene and norbixin exhibit intense fluorescence peaks at 492 nm, 493 nm and 500 nm, respectively. These peaks are assigned to intermediate peroxy/epoxy compounds of the three molecules that are formed with molecular oxygen prior to the formation of oxidized short-chain stable compounds. - Highlights: • Fluorescence and UV–vis studies on β-carotene, lycopene and norbixin. • Oxidation, induced by FeCl 3 in CH 2 Cl 2 shows blue shifted fluorescence peaks. • Fluorescence peaks were assigned to intermediate peroxy/epoxy forms of carotenoids. • The D0→D3 transition of radical cations are observed in the near IR region

  5. Future needs and recommendations in the development of species sensitivity distributions: Estimating toxicity thresholds for aquatic ecological communities and assessing impacts of chemical exposures.

    Science.gov (United States)

    Belanger, Scott; Barron, Mace; Craig, Peter; Dyer, Scott; Galay-Burgos, Malyka; Hamer, Mick; Marshall, Stuart; Posthuma, Leo; Raimondo, Sandy; Whitehouse, Paul

    2017-07-01

    A species sensitivity distribution (SSD) is a probability model of the variation of species sensitivities to a stressor, in particular chemical exposure. The SSD approach has been used as a decision support tool in environmental protection and management since the 1980s, and the ecotoxicological, statistical, and regulatory basis and applications continue to evolve. This article summarizes the findings of a 2014 workshop held by the European Centre for Toxicology and Ecotoxicology of Chemicals and the UK Environment Agency in Amsterdam, The Netherlands, on the ecological relevance, statistical basis, and regulatory applications of SSDs. An array of research recommendations categorized under the topical areas of use of SSDs, ecological considerations, guideline considerations, method development and validation, toxicity data, mechanistic understanding, and uncertainty were identified and prioritized. A rationale for the most critical research needs identified in the workshop is provided. The workshop reviewed the technical basis and historical development and application of SSDs, described approaches to estimating generic and scenario-specific SSD-based thresholds, evaluated utility and application of SSDs as diagnostic tools, and presented new statistical approaches to formulate SSDs. Collectively, these address many of the research needs to expand and improve their application. The highest priority work, from a pragmatic regulatory point of view, is to develop a guidance of best practices that could act as a basis for global harmonization and discussions regarding the SSD methodology and tools. Integr Environ Assess Manag 2017;13:664-674. © 2016 SETAC. © 2016 SETAC.

  6. Spectroscopic studies of neutral and chemically oxidized species of β-carotene, lycopene and norbixin in CH{sub 2}Cl{sub 2}: Fluorescence from intermediate compounds

    Energy Technology Data Exchange (ETDEWEB)

    Alwis, D.D.D.H [Department of Chemistry, The Open University of Sri Lanka, Nawala (Sri Lanka); Department of Chemistry, University of Sri Jayewardenepura, Nugegoda (Sri Lanka); Chandrika, U.G. [Department of Biochemistry, University of Sri Jayewardenepura, Nugegoda (Sri Lanka); Jayaweera, P.M., E-mail: pradeep@sjp.ac.lk [Department of Chemistry, University of Sri Jayewardenepura, Nugegoda (Sri Lanka)

    2015-02-15

    Radical cations, dications and oxidized intermediate species of three carotenoids, namely, β-carotene, lycopene and norbixin, were generated in CH{sub 2}Cl{sub 2} solutions via chemical oxidation using anhydrous FeCl{sub 3}. UV–vis, fluorescence and fluorescence-excitation spectroscopic studies were performed to understand and compare the nature of intermediate species generated during the chemical oxidation process and subsequent degradation. The intense emission observed at 550 nm can be assigned to the S{sub 2}→S{sub 0} (1{sup 1}B{sub u}→1{sup 1}A{sub g}) transition of the carotenoid molecules. The 350 nm excitation during the oxidation process for β-carotene, lycopene and norbixin exhibit intense fluorescence peaks at 492 nm, 493 nm and 500 nm, respectively. These peaks are assigned to intermediate peroxy/epoxy compounds of the three molecules that are formed with molecular oxygen prior to the formation of oxidized short-chain stable compounds. - Highlights: • Fluorescence and UV–vis studies on β-carotene, lycopene and norbixin. • Oxidation, induced by FeCl{sub 3} in CH{sub 2}Cl{sub 2} shows blue shifted fluorescence peaks. • Fluorescence peaks were assigned to intermediate peroxy/epoxy forms of carotenoids. • The D0→D3 transition of radical cations are observed in the near IR region.

  7. CHEMICAL CHARACTERIZATION OF Lavandula angustifolia Mill. WHICH IS A PHYTOCOSMETIC SPECIES AND INVESTIGATION OF ITS ANTIMICROBIAL EFFECT IN COSMETIC PRODUCTS

    Directory of Open Access Journals (Sweden)

    Aslıhan Cesur Turgut

    2016-11-01

    Full Text Available Lavander (Lavandula sp. is a precious essential oil plant from the Lamiaceae family. There are 39 lavender species (Lavandula sp. most of which have Mediterranean origin and among them three have high commercial value. While the essential oil quality of the lavender species (British lavender is high the lavandin species (hybrid lavender have high essential oil yield [2, 52]. In this study, the content of the extracts obtained from Lavandula angustifolia, which were grown in Burdur Örtülü locality, was determined via HPLC and GC analysis and the anti-microbial effect of the essential oil L. angustifolia was investigated. The study was made with the dried flowers of L. angustifolia. Some of the dried flowers were extracted and the essential oil was distilled from the remaining part. Various phenolic compounds in the extract were quantitatively determined by HPLC. Quantitatively cafeic, rosemeric and the 4-hydroxybenzoic acids were the most abundant phenolic acids in the content in decreasing order. In the GC analysis 31 different compounds were determined: Linalool and Linalil Acetate having the highest concentration. Anti-microbial effect was determined against the most frequently encountered microorganisms in the cosmetics: Candida albicans, Staphylococcus aureus, Pseudomonas aeruginosa, Aspergillus brasiliensis. According to the results it is concluded that the essential oil, L. angustifolia, can be used either directly or incorporated into the cosmetics without the necessity for any other extra preservative against the said microrganisms. According to the literature these microorganisms, which are frequently found in creams, cause various diseases. It was observed that the essential oil L. Angustifolia could completely remove the contamination caused by the said micro-organisms as of the 14. day.

  8. Regulation of redox reactions of chemical species (arsenic and chromium) in sediment of Marque river. From experimentation to modeling

    International Nuclear Information System (INIS)

    Gorny, Josselin

    2015-01-01

    The French national radioactive waste management agency (Andra) and the Nord-Pas de Calais (NPDC) Region aim to better understand the fate of the redox sensitive trace elements in soils and river sediments to ameliorate the management of polluted sediments and of the storage of radioactive wastes. To address this problematic, some river sediments were selected as proxies, as strong redox gradients can be observed. Two methods have been developed to study the speciation of As and Cr: (i) HPIC-ICP-MS (High Performance Ionic Performance - Inductively Coupled Plasma - Mass Spectrometry) coupling in order to separate and quantify As [As(III), As(V), DMMA V and MMAA V ] and Cr species [Cr(III) and Cr(VI)], and (ii) DGT probes (Diffusive Gradient in Thin Film) containing specific chelating binding gels to quantify As species [As(III) and total As]. These methods have been implemented to monitor the low contaminated pore waters of the Marque river during 9 months. The results demonstrated that chromium is present only under its reduced form Cr(III), which makes difficult to assess the parameters that force redox interconversions between Cr(III) and Cr(VI). Arsenic is present only under its inorganic forms: As(III), As(V), and thio-arsenical species. Seasonal changes of As speciation in the dissolved phase depends mainly of S(-II) production by sulfate-reducing bacteria, which makes the amount of dissolved S(- II) an important parameter to follow through time since the As reduction increases its mobility and toxicity. (author) [fr

  9. Determination of the sources of the airborne physico-chemical 131I species in a PWR power plant

    International Nuclear Information System (INIS)

    Deuber, H.; Wilhelm, J.G.

    1978-01-01

    In a 1300 MWE PWR power plant the sources of the airborne 131 I species were determined over a period of 5 months. During power operation the main source of the radiologically decisive elemental 131 I was the exhaust from the hoods in which samples from the primary coolant are taken and processed. During refueling outage elemental 131 I was mainly contributed by the containment purge air. By efficient filtration of these exhausts, a reduction of the ingestion dose, caused by the total 131 I stack release, by a factor of nearly 4 during power operation and of possibly 10 during refueling outage can be accomplished. (author)

  10. Quantification of chemical sulphur species in bulk soil and organic sulphur fractions by S K-edge Xanes spectroscopy

    DEFF Research Database (Denmark)

    Boye, K; Almkvist, G; Nilsson, S I

    2011-01-01

    residue (CR) incorporation and farmyard manure (FYM) application, with equal applications of mineral nutrients were included in the study. In the new data treatment method, internally calibrated spectra of dilute solutions (30 mm) of model compounds were used to fit the sample spectra. This greatly...... the opposite trend was observed. Sulphur XANES spectroscopy of acetylacetone extracts of physically protected and unprotected organic S in two of the soils revealed that physical protection was not related to S speciation; however, intermediate forms of oxidized S species appeared to accumulate in the residual...

  11. Chemical modeling of groundwater in the Banat Plain, southwestern Romania, with elevated As content and co-occurring species by combining diagrams and unsupervised multivariate statistical approaches.

    Science.gov (United States)

    Butaciu, Sinziana; Senila, Marin; Sarbu, Costel; Ponta, Michaela; Tanaselia, Claudiu; Cadar, Oana; Roman, Marius; Radu, Emil; Sima, Mihaela; Frentiu, Tiberiu

    2017-04-01

    The study proposes a combined model based on diagrams (Gibbs, Piper, Stuyfzand Hydrogeochemical Classification System) and unsupervised statistical approaches (Cluster Analysis, Principal Component Analysis, Fuzzy Principal Component Analysis, Fuzzy Hierarchical Cross-Clustering) to describe natural enrichment of inorganic arsenic and co-occurring species in groundwater in the Banat Plain, southwestern Romania. Speciation of inorganic As (arsenite, arsenate), ion concentrations (Na + , K + , Ca 2+ , Mg 2+ , HCO 3 - , Cl - , F - , SO 4 2- , PO 4 3- , NO 3 - ), pH, redox potential, conductivity and total dissolved substances were performed. Classical diagrams provided the hydrochemical characterization, while statistical approaches were helpful to establish (i) the mechanism of naturally occurring of As and F - species and the anthropogenic one for NO 3 - , SO 4 2- , PO 4 3- and K + and (ii) classification of groundwater based on content of arsenic species. The HCO 3 - type of local groundwater and alkaline pH (8.31-8.49) were found to be responsible for the enrichment of arsenic species and occurrence of F - but by different paths. The PO 4 3- -AsO 4 3- ion exchange, water-rock interaction (silicates hydrolysis and desorption from clay) were associated to arsenate enrichment in the oxidizing aquifer. Fuzzy Hierarchical Cross-Clustering was the strongest tool for the rapid simultaneous classification of groundwaters as a function of arsenic content and hydrogeochemical characteristics. The approach indicated the Na + -F - -pH cluster as marker for groundwater with naturally elevated As and highlighted which parameters need to be monitored. A chemical conceptual model illustrating the natural and anthropogenic paths and enrichment of As and co-occurring species in the local groundwater supported by mineralogical analysis of rocks was established. Copyright © 2016 Elsevier Ltd. All rights reserved.

  12. Differential Biofilm Formation and Chemical Disinfection Resistance of Sessile Cells of Listeria monocytogenes Strains under Monospecies and Dual-Species (with Salmonella enterica) Conditions

    Science.gov (United States)

    Kostaki, Maria; Chorianopoulos, Nikos; Braxou, Elli; Nychas, George-John

    2012-01-01

    This study aimed to investigate the possible influence of bacterial intra- and interspecies interactions on the ability of Listeria monocytogenes and Salmonella enterica to develop mixed-culture biofilms on an abiotic substratum, as well as on the subsequent resistance of sessile cells to chemical disinfection. Initially, three strains from each species were selected and left to attach and form biofilms on stainless steel (SS) coupons incubated at 15°C for 144 h, in periodically renewable tryptone soy broth (TSB), under either monoculture or mixed-culture (mono-/dual-species) conditions. Following biofilm formation, mixed-culture sessile communities were subjected to 6-min disinfection treatments with (i) benzalkonium chloride (50 ppm), (ii) sodium hypochlorite (10 ppm), (iii) peracetic acid (10 ppm), and (iv) a mixture of hydrogen peroxide (5 ppm) and peracetic acid (5 ppm). Results revealed that both species reached similar biofilm counts (ca. 105 CFU cm−2) and that, in general, interspecies interactions did not have any significant effect either on the biofilm-forming ability (as this was assessed by agar plating enumeration of the mechanically detached biofilm bacteria) or on the antimicrobial resistance of each individual species. Interestingly, pulsed-field gel electrophoresis (PFGE) analysis clearly showed that the three L. monocytogenes strains did not contribute at the same level either to the formation of mixed-culture sessile communities (mono-/dual species) or to their antimicrobial recalcitrance. Additionally, the simultaneous existence inside the biofilm structure of S. enterica cells seemed to influence the occurrence and resistance pattern of L. monocytogenes strains. In sum, this study highlights the impact of microbial interactions taking place inside a mixed-culture sessile community on both its population dynamics and disinfection resistance. PMID:22307304

  13. Chemical speciation of arsenic species in human blood serum by liquid chromatography using a phosphatidylcholine-coated ODS column with detection by ICP-MS

    International Nuclear Information System (INIS)

    Hasegawa, Takuya; Ishise, Jotaro; Fukumoto, Yasuharu; Matsuura, Hirotaka; Zhu, Yanbei; Umemura, Tomonari; Haraguchi, Hiroki; Yamamoto, Kazuhito; Naoe, Tomoki

    2007-01-01

    Chemical speciation of arsenic species in human blood serum was performed by high-performance liquid chromatography/inductively coupled plasma mass spectrometry (HPLC/ICP-MS) with direct sample injection, where an octadecylsilyl silica (ODS) column coated with phosphatidylcholine (PC) (hereafter known as 'PC-coated ODS column') was used as the separation column. In arsenic species analysis, a citrate buffer solution (pH 4.0) was used as the mobile phase, in which the following reagents were added: sodium 1-dodecanesulfonate (SDS), tetramethylammonium hydroxide (TMAH), which are ion-pair reagents to separate inorganic and organic arsenic species, and 3-[(3-cholamidopropyl)-dimethylammonio]-1-propane sulfonate (CHAPS), which is a protein-solubilizing agent to prevent adsorption of proteins on the column. As a result of optimization, five representative arsenic species spiked in human blood serum reference material could be separated from each other within 5 min on the PC-coated ODS column by elution with a 5 mM citrate buffer (pH 4.0) containing 5 mM SDS, 5 mM THAH, and 0.2 mM CHAPS. The detection limits obtained by ICP-MS were 3.1, 2.7, 4.5, 2.5, and 2.5 ng of As g -1 for arsenate (iAs V ), arsenite (iAs III ), monomethylarsonic acid (MMA), dimethylarsenic acid (DMA), and arsenobetaine (AB), respectively, when the injection volume was 20 μL. The present separation system was also applied to speciation analysis of arsenic species in human blood serum collected from a leukemia patient after therapeutic treatment with arsenic. (author)

  14. Growing Azolla to produce sustainable protein feed: the effect of differing species and CO2 concentrations on biomass productivity and chemical composition.

    Science.gov (United States)

    Brouwer, Paul; Schluepmann, Henriette; Nierop, Klaas Gj; Elderson, Janneke; Bijl, Peter K; van der Meer, Ingrid; de Visser, Willem; Reichart, Gert-Jan; Smeekens, Sjef; van der Werf, Adrie

    2018-03-24

    Since available arable land is limited and nitrogen fertilizers pollute the environment, cropping systems ought to be developed that do not rely on them. Here we investigate the rapidly growing, N 2 -fixing Azolla/Nostoc symbiosis for its potential productivity and chemical composition to determine its potential as protein feed. In a small production system, cultures of Azolla pinnata and Azolla filiculoides were continuously harvested for over 100 days, yielding an average productivity of 90.0-97.2 kg dry weight (DW) ha -1  d -1 . Under ambient CO 2 levels, N 2 fixation by the fern's cyanobacterial symbionts accounted for all nitrogen in the biomass. Proteins made up 176-208 g kg -1 DW (4.9 × total nitrogen), depending on species and CO 2 treatment, and contained more essential amino acids than protein from soybean. Elevated atmospheric CO 2 concentrations (800 ppm) significantly boosted biomass production by 36-47%, without decreasing protein content. Choice of species and CO 2 concentrations further affected the biomass content of lipids (79-100 g kg -1 DW) and (poly)phenols (21-69 g kg -1 DW). By continuous harvesting, high protein yields can be obtained from Azolla cultures, without the need for nitrogen fertilization. High levels of (poly)phenols likely contribute to limitations in the inclusion rate of Azolla in animal diets and need further investigation. © 2018 The Authors. Journal of the Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. © 2018 The Authors. Journal of the Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

  15. Essential Oils Extracted Using Microwave-Assisted Hydrodistillation from Aerial Parts of Eleven Artemisia Species: Chemical Compositions and Diversities in Different Geographical Regions of Iran

    Directory of Open Access Journals (Sweden)

    Majid Mohammadhosseini

    2017-03-01

    Full Text Available This study aimed to assess the chemical compositions of essential oils (EOs extracted through microwave-assisted hydrodistillation from aerial parts of 11 Artemisia species growing wild in different regions in Northern, Eastern, Western, and Central parts of Iran. The EOs were subsequently analyzed via GC and GC-MS. The percentage yields of the EOs varied over the range of 0.21-0.50 (w/w%. On the basis of these characterizations and spectral assignments, natural compounds including camphor, 1,8-cineole, camphene, α-pinene, β-pinene, β-thujone, and sabinene were the most abundant and frequent constituents among all studied chemical profiles. Accordingly, oxygenated monoterpenes, monoterpene hydrocarbons, and non-terpene hydrocarbons were the dominant groups of natural compounds in the chemical profiles of 13, 4, and 2 samples, respectively. Moreover, five chemotypes were identified using statistical analyses: camphene, α-pinene and β-pinene; 1,8-cineole; camphore and 1,8-cineole; camphore and camphore and β-thujone.

  16. The source, discharge, and chemical characteristics of selected springs, and the abundance and health of associated endemic anuran species in the Mojave network parks

    Science.gov (United States)

    Schroeder, Roy A.; Smith, Gregory A.; Martin, Peter; Flint, Alan L.; Gallegos, Elizabeth; Fisher, Robert N.; Martin, Peter; Schroeder, Roy A.

    2015-01-01

    Hydrological and biological investigations were done during 2005 and 2006 in cooperation with the U.S. National Park Service to investigate the source, discharge, and chemical characteristics of selected springs and the abundance and health of endemic anuran (frog and toad) species at Darwin Falls in Death Valley National Park, Piute Spring in Mojave National Preserve, and Fortynine Palms Oasis in Joshua Tree National Park. Discharge from the springs at these sites sustains isolated riparian habitats in the normally dry Mojave Desert. Data were collected on water quantity (discharge) and quality, air and water temperature, and abundance and health of endemic anuran species. In addition, a single survey of the abundance and health of endemic anuran species was completed at Rattlesnake Canyon in Joshua Tree National Park. Results from this study were compared to limited historical data, where they exist, and can provide a baseline for future hydrological and biological investigations to evaluate the health and sustainability of the resource and its response to changing climate and increasing human use.

  17. Nonlinear Stability and Structure of Compressible Reacting Mixing Layers

    Science.gov (United States)

    Day, M. J.; Mansour, N. N.; Reynolds, W. C.

    2000-01-01

    The parabolized stability equations (PSE) are used to investigate issues of nonlinear flow development and mixing in compressible reacting shear layers. Particular interest is placed on investigating the change in flow structure that occurs when compressibility and heat release are added to the flow. These conditions allow the 'outer' instability modes- one associated with each of the fast and slow streams-to dominate over the 'central', Kelvin-Helmholtz mode that unaccompanied in incompressible nonreacting mixing layers. Analysis of scalar probability density functions in flows with dominant outer modes demonstrates the ineffective, one-sided nature of mixing that accompany these flow structures. Colayer conditions, where two modes have equal growth rate and the mixing layer is formed by two sets of vortices, offer some opportunity for mixing enhancement. Their extent, however, is found to be limited in the mixing layer's parameter space. Extensive validation of the PSE technique also provides a unique perspective on central- mode vortex pairing, further supporting the view that pairing is primarily governed perspective sheds insight on how linear stability theory is able to provide such an accurate prediction of experimentally-observed, fully nonlinear flow phenomenon.

  18. Motivation, procedures and aims of reacting plasma experiments

    International Nuclear Information System (INIS)

    Miyahara, Akira

    1982-01-01

    A project of reacting plasma experiment (R-project) was proposed at the Institute of Plasma Physics (IPP), Nagoya University. It is necessary to bridge plasma physics and fusion engineering by means of a messenger wire like burning plasma experiment. This is a motivation of the R-project. The university linkage organization of Japan for fusion engineering category carried out a lot of contribution to R-tokamak design. The project consists of four items, namely, R-tokamak design, research and development (R and D), site and facilities, and international collaboration. The phase 1 experiment (R 1 - phase) corresponds to burning plasma experiment without D + T fuel, while the phase-2 experiment (R 2 -phase) with D + T fuel. One reference design was finished. Intensive efforts have been carried out by the R and D team on the following items, wall material, vacuum system, tritium system, neutronics, remote control system, pulsed superconducting magnet development, negative ion source, and alpha-particle diagnostics. The problems concerning site and major facilities are also important, because tritium handling, neutron and gamma-ray sky shines and the activation of devices cause impact to surrounding area. The aims of burning plasma experiment are to enter tritium into the fusion device, and to study burning plasma physics. (Kato, T.)

  19. CERN reacts to increased costs to completion of the LHC

    CERN Multimedia

    2002-01-01

    Aspects of LHC construction. The CERN Council, where the representatives of the 20 Member States of the Organization decide on scientific programmes and financial resources, held its 120th session on 14 December under the chairmanship of Prof. Maurice Bourquin (CH). CERN adjusts to the LHC Director-General, Luciano Maiani, stressed that CERN was now fully engaged in the LHC and outlined the first moves to react to the increased cost to completion of the LHC. The new accelerator is an extremely complex, high-tech project which CERN is building under very severe conditions. However, the technical challenges are solved and industrial production of accelerator elements, and installation are starting. Professor Maiani said that 2001 had been a very hard but decisive year for CERN. An important milestone had been passed during this meeting with the approval of the LHC dipole magnets contract, the last major contract for the accelerator. The new costs to completion of the LHC project are now clear. A first propos...

  20. The chilling effect: how do researchers react to controversy?

    Directory of Open Access Journals (Sweden)

    Joanna Kempner

    2008-11-01

    Full Text Available BACKGROUND: Can political controversy have a "chilling effect" on the production of new science? This is a timely concern, given how often American politicians are accused of undermining science for political purposes. Yet little is known about how scientists react to these kinds of controversies. METHODS AND FINDINGS: Drawing on interview (n = 30 and survey data (n = 82, this study examines the reactions of scientists whose National Institutes of Health (NIH-funded grants were implicated in a highly publicized political controversy. Critics charged that these grants were "a waste of taxpayer money." The NIH defended each grant and no funding was rescinded. Nevertheless, this study finds that many of the scientists whose grants were criticized now engage in self-censorship. About half of the sample said that they now remove potentially controversial words from their grant and a quarter reported eliminating entire topics from their research agendas. Four researchers reportedly chose to move into more secure positions entirely, either outside academia or in jobs that guaranteed salaries. About 10% of the group reported that this controversy strengthened their commitment to complete their research and disseminate it widely. CONCLUSIONS: These findings provide evidence that political controversies can shape what scientists choose to study. Debates about the politics of science usually focus on the direct suppression, distortion, and manipulation of scientific results. This study suggests that scholars must also examine how scientists may self-censor in response to political events.

  1. The Chilling Effect: How Do Researchers React to Controversy?

    Science.gov (United States)

    Kempner, Joanna

    2008-01-01

    Background Can political controversy have a “chilling effect” on the production of new science? This is a timely concern, given how often American politicians are accused of undermining science for political purposes. Yet little is known about how scientists react to these kinds of controversies. Methods and Findings Drawing on interview (n = 30) and survey data (n = 82), this study examines the reactions of scientists whose National Institutes of Health (NIH)-funded grants were implicated in a highly publicized political controversy. Critics charged that these grants were “a waste of taxpayer money.” The NIH defended each grant and no funding was rescinded. Nevertheless, this study finds that many of the scientists whose grants were criticized now engage in self-censorship. About half of the sample said that they now remove potentially controversial words from their grant and a quarter reported eliminating entire topics from their research agendas. Four researchers reportedly chose to move into more secure positions entirely, either outside academia or in jobs that guaranteed salaries. About 10% of the group reported that this controversy strengthened their commitment to complete their research and disseminate it widely. Conclusions These findings provide evidence that political controversies can shape what scientists choose to study. Debates about the politics of science usually focus on the direct suppression, distortion, and manipulation of scientific results. This study suggests that scholars must also examine how scientists may self-censor in response to political events. PMID:19018657

  2. Chemical composition and antifungal activity of essential oil of Salvia sclarea L. from Bulgaria against isolates of Candida species

    Directory of Open Access Journals (Sweden)

    Yana Hristova

    2013-01-01

    Full Text Available The essential oil of Salvia sclarea L., growing in Bulgaria, was analyzed by gas chromatography – mass spectrometry. A total of 52 different compounds were identified, representing 98.25% of total oil content. Linalyl acetate (56.88% and linalool (20.75% were determined as major essential oil constituents, followed by germacrene D (5.08% and β-cariophyllene (3.41%. Antifungal activities of clary sage essential oil and major compounds linalyl acetate and linalool against 30 clinical isolates, belonging to species Candida albicans, Candida tropicalis, Candida krusei, Candida glabrata and Candida parapsilosis were evaluated. Essential oil characterized with stronger anticandidial activity in comparison with pure compounds.

  3. Occurrence and spatial distribution of chemical contaminants in edible fish species collected from UK and proximate marine waters.

    Science.gov (United States)

    Fernandes, A R; Mortimer, D; Holmes, M; Rose, M; Zhihua, L; Huang, X; Smith, F; Panton, S; Marshall, L

    2018-05-01

    The occurrence of a range of regulated and emerging organic environmental contaminants was investigated in 182 samples of edible marine fish sampled mainly from UK marine regions, but extending northerly to the coast of Norway and south to the Algarve. These species (sprats, mackerel, turbot, halibut, herring, grey mullet, sea bass, grey mullet, sardines, etc.) are among those considered to be at the highest risk of contamination with regulated contaminants such as polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs, dioxins), and polychlorinated biphenyls (PCBs), but the occurrence of polybrominated diphenylethers (PBDEs) and polybrominated biphenyls (PBBs) was also investigated. Sub-sets of samples (50-75) were also analysed for emerging contaminants: polychlorinated naphthalenes (PCNs), polybrominated and mixed halogenated dibenzo-p-dioxins, dibenzofurans and biphenyls (PBDD/Fs, PXDD/Fs and PXBs) and perfluoroalkyl substances (PFAS). Contaminant occurrence varied with species and location, but all measured contaminants were detected, with sprats, sea bass, sardines, mackerel, and herring showing higher tissue concentrations. The concentrations of the different contaminants in the various samples were mapped utilising the GPS coordinate data of the capture locations to visualise spatial distribution levels. In terms of catch location, fish sampled from the coasts of southern Britain, north-western France and the Irish Sea appeared to contain proportionately higher levels of some contaminants - e.g. samples from the Irish Sea tended to show higher PCN concentrations, whereas higher levels of PCBs were observed in some fish sampled off the coasts of northern France. Similarly, samples of mullet from the southeast coast of UK showed much higher concentrations of BDE-99 than the other regions. In terms of occurrence trends, PCDD/F and PCB concentrations show a modest decline over the last decade but where limited background data is available for emerging

  4. Characterization of the parameters at the origin of the chemical species hideout process at the fuel rod surface in boiling conditions

    International Nuclear Information System (INIS)

    Peybernes, J.; March, P.

    1999-01-01

    Current trends in nuclear power generation (and particularly in pressurized water reactors) are toward plant life extension and extended fuel burnup. A higher heat generation rate can induce local boiling regimes at the fuel rod surface in the hottest channels of the core, which can strongly modify the chemical environment of the cladding and influence the oxidation rate of zirconium alloys. Tests performed in out-of-pile loops under severe chemical and thermal-hydraulic conditions (nucleate boiling, higher lithium contents compared to PWRs) reveal two important phenomena: an increase of the oxidation rate of Zircaloy-4 cladding materials in 'high' lithiated environments; an enrichment of the chemical additives in the primary water (boron, lithium) at the surface of the cladding under nucleate boiling conditions. The latter phenomenon, also called 'hideout effect', is mainly controlled by some thermal hydraulic parameters such as bubble diameters and nucleation site density. These parameters strongly depend on the oxide morphology (roughness, porosity). The lack of reliable data in high temperature water environments has led to the development of a specific instrumentation based on visualization. The fitting of windows on the REGGAE out-of-pile loop provides an optical access to the two-phase flow regime under PWR operating conditions, allowing for the characterization of the parameters at the origin of the chemical species hideout process. These direct observations of the cladding surfaces subjected to nucleate boiling conditions provide information about the development of the boiling mechanisms in relation to the morphology of the oxide layers (porosity, thickness, roughness). (author)

  5. Insulation and Heat Treatment of Bi-2212 Wire for Wind-and-React Coils

    Energy Technology Data Exchange (ETDEWEB)

    Peter K. F. Hwang

    2007-10-22

    Higher Field Magnets demand higher field materials such as Bi-2212 round superconducting wire. The Bi-2212 wire manufacture process depends on the coil fabrication method and wire insulation material. Considering the wind-and-react method, the coil must unifirmly heated to the melt temperature and uniformly cooled to the solidification temperature. During heat treat cycle for tightly wound coils, the leakage melt from conductor can chemically react with insulation on the conductor and creat short turns in the coils. In this research project, conductor, insulation, and coils are made to systemically study the suitable insulation materials, coil fabrication method, and heat treatment cycles. In this phase I study, 800 meters Bi-2212 wire with 3 different insulation materials have been produced. Best insulation material has been identified after testing six small coils for insulation integrity and critical current at 4.2 K. Four larger coils (2" dia) have been also made with Bi-2212 wrapped with best insulation and with different heattreatment cycle. These coils were tested for Ic in a 6T background field and at 4.2 K. The test result shows that Ic from 4 coils are very close to short samples (1 meter) result. It demonstrates that HTS coils can be made with Bi-2212 wire with best insulation consistently. Better wire insulation, improving coil winding technique, and wire manufacture process can be used for a wide range of high field magnet application including acclerators such as Muon Collider, fusion energy research, NMR spectroscopy, MRI, and other industrial magnets.

  6. Insulation and Heat Treatment of Bi-2212 Wires for Wind-and-React Coils

    International Nuclear Information System (INIS)

    Hwang, Peter K.F.

    2007-01-01

    Higher Field Magnets demand higher field materials such as Bi-2212 round superconducting wire. The Bi-2212 wire manufacture process depends on the coil fabrication method and wire insulation material. Considering the wind-and-react method, the coil must unifirmly heated to the melt temperature and uniformly cooled to the solidification temperature. During heat treat cycle for tightly wound coils, the leakage melt from conductor can chemically react with insulation on the conductor and creat short turns in the coils. In this research project, conductor, insulation, and coils are made to systemically study the suitable insulation materials, coil fabrication method, and heat treatment cycles. In this phase I study, 800 meters Bi-2212 wire with 3 different insulation materials have been produced. Best insulation material has been identified after testing six small coils for insulation integrity and critical current at 4.2 K. Four larger coils (2-inch dia) have been also made with Bi-2212 wrapped with best insulation and with different heattreatment cycle. These coils were tested for Ic in a 6T background field and at 4.2 K. The test result shows that Ic from 4 coils are very close to short samples (1 meter) result. It demonstrates that HTS coils can be made with Bi-2212 wire with best insulation consistently. Better wire insulation, improving coil winding technique, and wire manufacture process can be used for a wide range of high field magnet application including acclerators such as Muon Collider, fusion energy research, NMR spectroscopy, MRI, and other industrial magnets.

  7. Coupled effects of the precipitation of secondary species on the mechanical behaviour and chemical degradation of concretes

    International Nuclear Information System (INIS)

    Planel, D.

    2002-06-01

    Sulfate attack of cement-based materials remains an important problem for the durability assessment of containers and disposal engineering barriers dedicated to the long-term storage of radioactive wastes since underground water which may reach these elements contains small quantities of sulfates (7-31 mmol/1). This work contributes to the study of sulfate-induced damage mechanisms, to their understanding and modelling. The experimental phases of this study aimed at the understanding of the different physico-chemical phenomena involved during an external sulfate attack at following their evolution and their impact on the transport and mechanical properties of the material. Leaching experiments in pure water and in a solution of sodium sulfate (with a sulfate content of 15 mmol/1), have been performed simultaneously on OPC paste (w/c 0,4)in order to allow a comparison of test results. The frequent analysis of the leachant has shown a consumption of sulfate ions by the matrix, proportional to the square rate of time. The use of X-Ray Diffraction on powders, obtained by scraping the calcium-depleted part of the samples, led a precise view of the cement paste mineralogy, during sulfate attack. The use of Scanning Electron Microscopy (SEM) and Energy Dispersive Spectrometer (EDS) confirmed the correctness of XRD profiles and brought important informations concerning cracking distribution and localisation. In addition, a visual monitoring of crack appearance and evolution completed the previous observations. Based on these experimental results, a simplified model accounting for the chemical degradation of cement paste in sulfated water has been proposed. A geochemical code, coupling the chemistry in solution with the reactive transport in porous media has been used for this purpose. The model accounts for the evolution of transport properties (diffusivity) associated with the calcium-depleting of the cement matrix and the precipitation of secondary phases (gypsum

  8. On the deduction of chemical reaction pathways from measurements of time series of concentrations.

    Science.gov (United States)

    Samoilov, Michael; Arkin, Adam; Ross, John

    2001-03-01

    We discuss the deduction of reaction pathways in complex chemical systems from measurements of time series of chemical concentrations of reacting species. First we review a technique called correlation metric construction (CMC) and show the construction of a reaction pathway from measurements on a part of glycolysis. Then we present two new improved methods for the analysis of time series of concentrations, entropy metric construction (EMC), and entropy reduction method (ERM), and illustrate (EMC) with calculations on a model reaction system. (c) 2001 American Institute of Physics.

  9. Entropy Filtered Density Function for Large Eddy Simulation of Turbulent Reacting Flows

    Science.gov (United States)

    Safari, Mehdi

    Analysis of local entropy generation is an effective means to optimize the performance of energy and combustion systems by minimizing the irreversibilities in transport processes. Large eddy simulation (LES) is employed to describe entropy transport and generation in turbulent reacting flows. The entropy transport equation in LES contains several unclosed terms. These are the subgrid scale (SGS) entropy flux and entropy generation caused by irreversible processes: heat conduction, mass diffusion, chemical reaction and viscous dissipation. The SGS effects are taken into account using a novel methodology based on the filtered density function (FDF). This methodology, entitled entropy FDF (En-FDF), is developed and utilized in the form of joint entropy-velocity-scalar-turbulent frequency FDF and the marginal scalar-entropy FDF, both of which contain the chemical reaction effects in a closed form. The former constitutes the most comprehensive form of the En-FDF and provides closure for all the unclosed filtered moments. This methodology is applied for LES of a turbulent shear layer involving transport of passive scalars. Predictions show favor- able agreements with the data generated by direct numerical simulation (DNS) of the same layer. The marginal En-FDF accounts for entropy generation effects as well as scalar and entropy statistics. This methodology is applied to a turbulent nonpremixed jet flame (Sandia Flame D) and predictions are validated against experimental data. In both flows, sources of irreversibility are predicted and analyzed.

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

    Science.gov (United States)

    Wang, Se; Wang, Zhuang

    2017-11-11

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

  11. A detailed study on chemical characterization of essential oil components of two Plectranthus species grown in Saudi Arabia

    Directory of Open Access Journals (Sweden)

    Merajuddin Khan

    2016-11-01

    Full Text Available The chemical composition of the essential oils of Plectranthus cylindraceus and Plectranthus arabicus grown in Saudi Arabia were analyzed using gas chromatography techniques (GC–MS, GC–FID, Co-GC, LRI determination, and database and literature searches using two different stationary phase columns (polar and nonpolar. The analysis led to the characterization of a total of 157 different compounds from both oils. In the oil derived from P. cylindraceus, 79 compounds were identified, whereas 132 compounds were identified in the oil derived from P. arabicus; these compounds account for 95.2% and 98.4% of the total oil compositions, respectively. The major constituents of P. cylindraceus oil were patchouli alcohol (55.5 ± 0.01%, 1,8-cineole (6.0 ± 0.01% and valerianol (3.8 ± 0.18%, whereas, the main compounds of the P. arabicus oil were 1,8-cineole (50.5 ± 1.37%, β-pinene (7.0 ± 0.08%, camphor (6.3 ± 0.19% and β-myrcene (4.1 ± 0.10%. To the best of our knowledge, patchouli alcohol found in high concentration in the P. cylindraceus oil has never been reported from the genus Plectranthus. Moreover, this is the first phytochemical study of P. arabicus.

  12. A numerical analysis for non-linear radiation in MHD flow around a cylindrical surface with chemically reactive species

    Directory of Open Access Journals (Sweden)

    Junaid Ahmad Khan

    2018-03-01

    Full Text Available Boundary layer flow around a stretchable rough cylinder is modeled by taking into account boundary slip and transverse magnetic field effects. The main concern is to resolve heat/mass transfer problem considering non-linear radiative heat transfer and temperature/concentration jump aspects. Using conventional similarity approach, the equations of motion and heat transfer are converted into a boundary value problem whose solution is computed by shooting method for broad range of slip coefficients. The proposed numerical scheme appears to improve as the strengths of magnetic field and slip coefficients are enhanced. Axial velocity and temperature are considerably influenced by a parameter M which is inversely proportional to the radius of cylinder. A significant change in temperature profile is depicted for growing wall to ambient temperature ratio. Relevant physical quantities such as wall shear stress, local Nusselt number and local Sherwood number are elucidated in detail. Keywords: Stretchable boundary, Thermal radiation, Chemical reaction, Mathematical modeling, Non-linear differential system, Mass transfer

  13. Chemical composition and antimicrobial activity of the essential oils of some species of Anthemis sect. Anthemis (Asteraceae) from Sicily.

    Science.gov (United States)

    Riccobono, Luana; Maggio, Antonella; Bruno, Maurizio; Spadaro, Vivienne; Raimondo, Francesco Maria

    2017-12-01

    The chemical composition of the essential oils isolated from the aerial parts of Anthemis arvensis L. subsp. arvensis, Anthemis cretica subsp. messanensis (Brullo) Giardina & Raimondo and from flowers and leaves of Anthemis cretica subsp. columnae (Ten.) Frezén were determinated by GC-FID and GC-MS analyses. Torreyol (85.4%) was recognised as the main constituent of the Anthemis arvensis subsp. arvensis essential oil, while in the essential oils of Anthemis cretica subsp. messanensis, collected on the rock and cultivated in Hortus Botanicus Panormitanus, (E)-chrysanthenyl acetate (28.8 and 24.2% resp.), 14-hydroxy-α-humulene (8.1 and 5.3% resp.), santolina triene (8 and 5.8% resp.) and α-pinene (6.7 and 5.4% resp.) prevailed. 18-cineole (13.3 and 12.2% resp.), was the main component of both flower and leaf oils of Anthemis cretica subsp. columnae together with δ-cadinene (9.0 and 8.2% resp.) and (E)-caryophyllene (8.3 and 5.6% resp.).

  14. Nanomotor dynamics in a chemically oscillating medium

    Energy Technology Data Exchange (ETDEWEB)

    Robertson, Bryan, E-mail: bryan.robertson@mail.utoronto.ca; Kapral, Raymond, E-mail: rkapral@chem.utoronto.ca [Chemical Physics Theory Group, Department of Chemistry, University of Toronto, Toronto, Ontario M5S 3H6 (Canada)

    2015-04-21

    Synthetic nanomotors powered by chemical reactions have potential uses as cargo transport vehicles in both in vivo and in vitro applications. In many situations, motors will have to operate in out-of-equilibrium complex chemically reacting media, which supply fuel to the motors and remove the products they produce. Using molecular simulation and mean-field theory, this paper describes some of the new features that arise when a chemically powered nanomotor, operating through a diffusiophoretic mechanism, moves in an environment that supports an oscillatory chemical reaction network. It is shown how oscillations in the concentrations in chemical species in the environment give rise to oscillatory motor dynamics. More importantly, since the catalytic reactions on the motor that are responsible for its propulsion couple to the bulk phase reaction network, the motor can change its local environment. This process can give rise to distinctive spatiotemporal structures in reaction-diffusion media that occur as a result of active motor motion. Such locally induced nonequilibrium structure will play an important role in applications that involve motor dynamics in complex chemical media.

  15. Nanomotor dynamics in a chemically oscillating medium

    International Nuclear Information System (INIS)

    Robertson, Bryan; Kapral, Raymond

    2015-01-01

    Synthetic nanomotors powered by chemical reactions have potential uses as cargo transport vehicles in both in vivo and in vitro applications. In many situations, motors will have to operate in out-of-equilibrium complex chemically reacting media, which supply fuel to the motors and remove the products they produce. Using molecular simulation and mean-field theory, this paper describes some of the new features that arise when a chemically powered nanomotor, operating through a diffusiophoretic mechanism, moves in an environment that supports an oscillatory chemical reaction network. It is shown how oscillations in the concentrations in chemical species in the environment give rise to oscillatory motor dynamics. More importantly, since the catalytic reactions on the motor that are responsible for its propulsion couple to the bulk phase reaction network, the motor can change its local environment. This process can give rise to distinctive spatiotemporal structures in reaction-diffusion media that occur as a result of active motor motion. Such locally induced nonequilibrium structure will play an important role in applications that involve motor dynamics in complex chemical media

  16. Linear models for sound from supersonic reacting mixing layers

    Science.gov (United States)

    Chary, P. Shivakanth; Samanta, Arnab

    2016-12-01

    We perform a linearized reduced-order modeling of the aeroacoustic sound sources in supersonic reacting mixing layers to explore their sensitivities to some of the flow parameters in radiating sound. Specifically, we investigate the role of outer modes as the effective flow compressibility is raised, when some of these are expected to dominate over the traditional Kelvin-Helmholtz (K-H) -type central mode. Although the outer modes are known to be of lesser importance in the near-field mixing, how these radiate to the far-field is uncertain, on which we focus. On keeping the flow compressibility fixed, the outer modes are realized via biasing the respective mean densities of the fast (oxidizer) or slow (fuel) side. Here the mean flows are laminar solutions of two-dimensional compressible boundary layers with an imposed composite (turbulent) spreading rate, which we show to significantly alter the growth of instability waves by saturating them earlier, similar to in nonlinear calculations, achieved here via solving the linear parabolized stability equations. As the flow parameters are varied, instability of the slow modes is shown to be more sensitive to heat release, potentially exceeding equivalent central modes, as these modes yield relatively compact sound sources with lesser spreading of the mixing layer, when compared to the corresponding fast modes. In contrast, the radiated sound seems to be relatively unaffected when the mixture equivalence ratio is varied, except for a lean mixture which is shown to yield a pronounced effect on the slow mode radiation by reducing its modal growth.

  17. Evaluation of Physico-Chemical and Fungal Species Associated with Oil Contaminated Soil from Selected Automobile Garage in Sokoto Metropolis

    Directory of Open Access Journals (Sweden)

    Hassan Muhammad Maishanu

    2018-03-01

    Full Text Available This study was conducted with a view to evaluating the physicochemical and mycological properties of different oil contaminated soils collected from three different automobile garages in Sokoto Metropolis, and uncontaminated soil from the temporary site, Usmanu Danfodiyo University, Sokoto (UDUS was used as the control. The pH was determined using pH meter model Hanna (H1991301, quantity of mineral elements was evaluated in accordance with Murphy and Fungi were isolated from the three oil contaminated samples (A, B. and C and the uncontaminated (sample D as control, this was done by standard procedure using the method of P. Ren, T. Jankun & B. Leaderer. The physical, chemical, and mineral elements from the oil-contaminated soils of the three automobile garages and control. The results of particle soil analysis revealed the high content of sandy soil (96.2 to 87.3 and silt is the lowest with (2.5–0.6. Magnesium had the highest concentration of studied minerals, ranging from 193 to 649.2 mg/kg. while PH result revealed that the soil samples were pH value ranged from (16.85–16.20 in oil Contaminated samples, while the control had 15.90, and electrical conductivity ranged from 12.8–13.8 % and 28 % in control, four fungal isolates Aspergillus sp., Penicillum sp., Mucor sp. and Sporobolomyces sp. were identified based on colonial, sexual and morphological characteristics. These fungal strains can be used in bioremediation process and oil pollution reduction in aquatic ecosystems.

  18. Chemical composition, toxicity and antioxidant activities of essential oils of stem bark of Nigerian species of guava (Psidium guajava Linn.)

    Science.gov (United States)

    Fasola, Taiye R.; Oloyede, Ganiyat Kehinde; Aponjolosun, Babalola S.

    2011-01-01

    Essential oil from the stem bark of Nigerian species of Psidium guajava of the family Myrtaceae was obtained by hydro-distillation using an all-glass Clavenger apparatus. GC and GC/MS analysis were carried out on the essential oil and was found to contain 62 compounds constituting 99.98 % of the total oil composition. The principal constituents are hydrocarbons, amines, amides and esters with 3,6-dioxa-2,4,5,7-tetraoctane,2,2,4,4,5,5,7,7-octamethyl (11.67 %) and cyclononane (10.66 %) dominating the total essential oil. Brine shrimp lethality test was carried out to determine the toxicity of the oils to living organisms (shrimps). LC50 value (µg/ml) of 1.0009 obtained showed that the essential oil of P. guajava stem bark was toxic. The antioxidant property of essential oil was investigated by measuring the decrease in absorption at 517 nm of 1,1-diphenyl-2-picrylhydrazyl radical (DPPH) in a UV/visible spectrophotometer. The oil showed better activity as a radical scavenger than α-tocopherol. The oil activity was 71.83 % at 0.2 mg/ml and the absorption is stoichiometric with respect to the number of electron taken up. Thus, the results of this study showed that the essential oil from P. guajava was not only toxic; it possessed antioxidant activity, which could exert beneficial actions against pathological alterations caused by the presence of highly reactive free radicals. The toxicity of the oil can be taken advantage of in the therapy of diseases involving cell or tumor growth. PMID:27857663

  19. Assessment of chemical and biological significance of arsenical species in the Maurice River drainage basin (N. J. ). Part I. Distribution in water and river and lake sediments

    Energy Technology Data Exchange (ETDEWEB)

    Faust, S.D.; Winka, A.J.; Belton, T.

    1987-01-01

    Levels of arsenic were determined in the bottom sediments and waters of the Maurice River, Blackwater Branch, and Union Lake, (N.J.) that were contaminated by a local chemical industry. This was the only known source of the arsenic. Levels of total arsenic in the sediments and waters were determined quarterly over the course of one year. Sediments were extracted for water soluble and total extractable arsenic fractions and partitioned into four species: monomethylarsonic acid (MMAA), dimethylarsinic acid (DMAA), arsenite (As(III)), and arsenate (As(V)). In Union Lake at a shallow sandy sediment site, As (V) predominates. In organic sediments, As (III) or (V) predominate depending upon the dissolved oxygen content of the overlying waters. The oxidations state of the arsenic was affected also by the seasonal lake cycles of stratifying or mixing.

  20. HS/GC-MS analyzed chemical composition of the aroma of fruiting bodies of two species of genus Lentinus (Higher Basidiomycetes).

    Science.gov (United States)

    Mata, Gerardo; Valdez, Karina; Mendoza, Remedios; Trigos, Ángel

    2014-01-01

    The chemical composition of the aroma of fresh fruiting bodies of the cultivated mushroom Lentinus boryanus is described here and compared with medicinal shiitake mushroom L. edodes. Volatile compounds were analyzed through headspace sampling coupled with gas chromatography-mass spectrometry. The mushrooms under study were grown on different substrates based on barley straw, sugarcane bagasse, oak wood sawdust, and beech leaf litter. It was determined that L. boryanus as well as L. edodes contain an abundant amount of a volatile compound identified as 3-octanone with a sweet fruity aroma. On the other hand, only L. boryanus produced 3-octanol a characteristic aroma of cod liver oil. In total, 10 aromatic compounds were identified, some of which were obtained exclusively in one species or substrate.

  1. Chemical and biological evaluation of essential oils from two species of Myrtaceae - Eugenia uniflora L. and Plinia trunciflora (O. Berg) Kausel.

    Science.gov (United States)

    Lago, João Henrique G; Souza, Elisângela Dutra; Mariane, Bruna; Pascon, Renata; Vallim, Marcelo A; Martins, Roberto Carlos C; Baroli, Adriana A; Carvalho, Bianca A; Soares, Marisi G; dos Santos, Roberta T; Sartorelli, Patricia

    2011-11-25

    The chemical composition and antimicrobial activity of essential oils obtained from leaves of two Myrtaceae species-Eugenia uniflora L. and Plinia trunciflora (O. Berg) Kausel-were determined. Analysis by GC/MS as well as determination of Kovatz indexes indicated atractylone (26.78%) and curzerene (17.96%) as major constituents of E. uniflora oil and α-cadinol (19.15%), apiole (11.15%) and cubenol (5.43%) as main components in P. trunciflora oil. Both essential oils were tested for antimicrobial activity against yeasts and bacteria. E. uniflora and P. trunciflora essential oils were active towards two Gram-positive bacteria, Streptococcus equi and Staphylococcus epidermis. In addition, biological activity of both essential oils was detected for pathogenic yeasts of the genus Candida and Cryptococcus. E. uniflora was active towards all yeast tested and exhibited interesting minimal inhibitory concentrations (0.11 to 3.75 mg/mL) across a broad spectrum of activity.

  2. Enhancement of chemically induced reactive oxygen species production and DNA damage in human SH-SY5Y neuroblastoma cells by 872 MHz radiofrequency radiation

    Energy Technology Data Exchange (ETDEWEB)

    Luukkonen, Jukka [Department of Environmental Science, University of Kuopio, Bioteknia 2, P.O. Box 1627, FI-70211 Kuopio (Finland)], E-mail: Jukka.Luukkonen@uku.fi; Hakulinen, Pasi; Maeki-Paakkanen, Jorma [Department of Environmental Health, National Public Health Institute, P.O. Box 95, FI-70701 Kuopio (Finland); Juutilainen, Jukka; Naarala, Jonne [Department of Environmental Science, University of Kuopio, Bioteknia 2, P.O. Box 1627, FI-70211 Kuopio (Finland)

    2009-03-09

    The objective of the study was to investigate effects of 872 MHz radiofrequency (RF) radiation on intracellular reactive oxygen species (ROS) production and DNA damage at a relatively high SAR value (5 W/kg). The experiments also involved combined exposure to RF radiation and menadione, a chemical inducing intracellular ROS production and DNA damage. The production of ROS was measured using the fluorescent probe dichlorofluorescein and DNA damage was evaluated by the Comet assay. Human SH-SY5Y neuroblastoma cells were exposed to RF radiation for 1 h with or without menadione. Control cultures were sham exposed. Both continuous waves (CW) and a pulsed signal similar to that used in global system for mobile communications (GSM) mobile phones were used. Exposure to the CW RF radiation increased DNA breakage (p < 0.01) in comparison to the cells exposed only to menadione. Comparison of the same groups also showed that ROS level was higher in cells exposed to CW RF radiation at 30 and 60 min after the end of exposure (p < 0.05 and p < 0.01, respectively). No effects of the GSM signal were seen on either ROS production or DNA damage. The results of the present study suggest that 872 MHz CW RF radiation at 5 W/kg might enhance chemically induced ROS production and thus cause secondary DNA damage. However, there is no known mechanism that would explain such effects from CW RF radiation but not from GSM modulated RF radiation at identical SAR.

  3. Enhancement of chemically induced reactive oxygen species production and DNA damage in human SH-SY5Y neuroblastoma cells by 872 MHz radiofrequency radiation

    International Nuclear Information System (INIS)

    Luukkonen, Jukka; Hakulinen, Pasi; Maeki-Paakkanen, Jorma; Juutilainen, Jukka; Naarala, Jonne

    2009-01-01

    The objective of the study was to investigate effects of 872 MHz radiofrequency (RF) radiation on intracellular reactive oxygen species (ROS) production and DNA damage at a relatively high SAR value (5 W/kg). The experiments also involved combined exposure to RF radiation and menadione, a chemical inducing intracellular ROS production and DNA damage. The production of ROS was measured using the fluorescent probe dichlorofluorescein and DNA damage was evaluated by the Comet assay. Human SH-SY5Y neuroblastoma cells were exposed to RF radiation for 1 h with or without menadione. Control cultures were sham exposed. Both continuous waves (CW) and a pulsed signal similar to that used in global system for mobile communications (GSM) mobile phones were used. Exposure to the CW RF radiation increased DNA breakage (p < 0.01) in comparison to the cells exposed only to menadione. Comparison of the same groups also showed that ROS level was higher in cells exposed to CW RF radiation at 30 and 60 min after the end of exposure (p < 0.05 and p < 0.01, respectively). No effects of the GSM signal were seen on either ROS production or DNA damage. The results of the present study suggest that 872 MHz CW RF radiation at 5 W/kg might enhance chemically induced ROS production and thus cause secondary DNA damage. However, there is no known mechanism that would explain such effects from CW RF radiation but not from GSM modulated RF radiation at identical SAR

  4. Influence of Polish Climate Conditions on Content and the Chemical Variation of Volatiles in the Roots of Six Eleutherococcus Species and Their Potential Use

    Directory of Open Access Journals (Sweden)

    Daniel Załuski

    2016-03-01

    Full Text Available The aim of this study was the term of the climate influence on essential oil and aroma components of six Eleutherococcus species [E. senticosus (Rupr. & Maxim. Maxim., E. setchuensis (Harms Nakai, E. sessiliflorus (Rupr. & Maxim. S. Y. Hu, E. gracilistylus (W. W. Smith S. Y. Hu, E. henryi Oliv., E. divaricatus (Siebold & Zucc. S. Y. Hu ] cultivated in Poland. The hydrodistilled volatiles of the samples were ranged from 0.2% to 0.4%. The components of the determined volatiles were analyzed by GC/MS/MS. Thirty of the same compounds were present in all samples. Major components of the samples were (E,E-farnesol (43.6-6.9%, (E,Z-farnesol (7.2-0.7%, (Z,E-farnesol (1.4-0.1%, tetradecanoic acid (9.91-2.08%, and pentadecanoic acid (12.8-3.5%. Highest (E,E-farnesol content (43.6% was determined in the roots of E. divaricatus. This compound may be considered as chemical marker of the species. This is the first time, when the analysis of volatiles in the roots of Eleutherococcus spp. cultivated in Poland was performed. This study provides a platform for further investigation for the isolation and pharmacological activity of active principles.

  5. Modeling reacting gases and aftertreatment devices for internal combustion engines

    Science.gov (United States)

    Depcik, Christopher David

    As more emphasis is placed worldwide on reducing greenhouse gas emissions, automobile manufacturers have to create more efficient engines. Simultaneously, legislative agencies want these engines to produce fewer problematic emissions such as nitrogen oxides and particulate matter. In response, newer combustion methods, like homogeneous charge compression ignition and fuel cells, are being researched alongside the old standard of efficiency, the compression ignition or diesel engine. These newer technologies present a number of benefits but still have significant challenges to overcome. As a result, renewed interest has risen in making diesel engines cleaner. The key to cleaning up the diesel engine is the placement of aftertreatment devices in the exhaust. These devices have shown great potential in reducing emission levels below regulatory levels while still allowing for increased fuel economy versus a gasoline engine. However, these devices are subject to many flow control issues. While experimental evaluation of these devices helps to understand these issues better, it is impossible to solve the problem through experimentation alone because of time and cost constraints. Because of this, accurate models are needed in conjunction with the experimental work. In this dissertation, the author examines the entire exhaust system including reacting gas dynamics and aftertreatment devices, and develops a complete numerical model for it. The author begins by analyzing the current one-dimensional gas-dynamics simulation models used for internal combustion engine simulations. It appears that more accurate and faster numerical method is available, in particular, those developed in aeronautical engineering, and the author successfully implements one for the exhaust system. The author then develops a comprehensive literature search to better understand the aftertreatment devices. A number of these devices require a secondary injection of fuel or reductant in the exhaust stream

  6. Rotational spectra of rare isotopic species of fluoroiodomethane: determination of the equilibrium structure from rotational spectroscopy and quantum-chemical calculations.

    Science.gov (United States)

    Puzzarini, Cristina; Cazzoli, Gabriele; López, Juan Carlos; Alonso, José Luis; Baldacci, Agostino; Baldan, Alessandro; Stopkowicz, Stella; Cheng, Lan; Gauss, Jürgen

    2012-07-14

    Supported by accurate quantum-chemical calculations, the rotational spectra of the mono- and bi-deuterated species of fluoroiodomethane, CHDFI and CD(2)FI, as well as of the (13)C-containing species, (13)CH(2)FI, were recorded for the first time. Three different spectrometers were employed, a Fourier-transform microwave spectrometer, a millimeter/submillimter-wave spectrometer, and a THz spectrometer, thus allowing to record a huge portion of the rotational spectrum, from 5 GHz up to 1.05 THz, and to accurately determine the ground-state rotational and centrifugal-distortion constants. Sub-Doppler measurements allowed to resolve the hyperfine structure of the rotational spectrum and to determine the complete iodine quadrupole-coupling tensor as well as the diagonal elements of the iodine spin-rotation tensor. The present investigation of rare isotopic species of CH(2)FI together with the results previously obtained for the main isotopologue [C. Puzzarini, G. Cazzoli, J. C. López, J. L. Alonso, A. Baldacci, A. Baldan, S. Stopkowicz, L. Cheng, and J. Gauss, J. Chem. Phys. 134, 174312 (2011); G. Cazzoli, A. Baldacci, A. Baldan, and C. Puzzarini, Mol. Phys. 109, 2245 (2011)] enabled us to derive a semi-experimental equilibrium structure for fluoroiodomethane by means of a least-squares fit procedure using the available experimental ground-state rotational constants together with computed vibrational corrections. Problems related to the missing isotopic substitution of fluorine and iodine were overcome thanks to the availability of an accurate theoretical equilibrium geometry (computed at the coupled-cluster singles and doubles level augmented by a perturbative treatment of triple excitations).

  7. Nitramine Monopropellant Deflagration and General Nonsteady Reacting Rocket Chamber Flows.

    Science.gov (United States)

    1980-01-01

    structure of RDX was also investigated by Harris,2 using X-ray diffraction. 2. The Crystalline Polymorphs of RMX HMX in the solid state exhibits four distinct...deflagration were shown to occur after transition . The critical transition pressure was found to correlate with the mean particle size of HMX and RDX ...Structure ....... ............ 4 2. The Crystalline Polymorphs of HMX ... ....... 5 3. Sublimation, Vaporization and Melting...... 6 C. The Chemical

  8. Multiphase integral reacting flow computer code (ICOMFLO): User`s guide

    Energy Technology Data Exchange (ETDEWEB)

    Chang, S.L.; Lottes, S.A.; Petrick, M.

    1997-11-01

    A copyrighted computational fluid dynamics computer code, ICOMFLO, has been developed for the simulation of multiphase reacting flows. The code solves conservation equations for gaseous species and droplets (or solid particles) of various sizes. General conservation laws, expressed by elliptic type partial differential equations, are used in conjunction with rate equations governing the mass, momentum, enthalpy, species, turbulent kinetic energy, and turbulent dissipation. Associated phenomenological submodels of the code include integral combustion, two parameter turbulence, particle evaporation, and interfacial submodels. A newly developed integral combustion submodel replacing an Arrhenius type differential reaction submodel has been implemented to improve numerical convergence and enhance numerical stability. A two parameter turbulence submodel is modified for both gas and solid phases. An evaporation submodel treats not only droplet evaporation but size dispersion. Interfacial submodels use correlations to model interfacial momentum and energy transfer. The ICOMFLO code solves the governing equations in three steps. First, a staggered grid system is constructed in the flow domain. The staggered grid system defines gas velocity components on the surfaces of a control volume, while the other flow properties are defined at the volume center. A blocked cell technique is used to handle complex geometry. Then, the partial differential equations are integrated over each control volume and transformed into discrete difference equations. Finally, the difference equations are solved iteratively by using a modified SIMPLER algorithm. The results of the solution include gas flow properties (pressure, temperature, density, species concentration, velocity, and turbulence parameters) and particle flow properties (number density, temperature, velocity, and void fraction). The code has been used in many engineering applications, such as coal-fired combustors, air

  9. Eco-friendly synthesis for MCM-41 nanoporous materials using the non-reacted reagents in mother liquor.

    Science.gov (United States)

    Ng, Eng-Poh; Goh, Jia-Yi; Ling, Tau Chuan; Mukti, Rino R

    2013-03-04

    Nanoporous materials such as Mobil composite material number 41 (MCM-41) are attractive for applications such as catalysis, adsorption, supports, and carriers. Green synthesis of MCM-41 is particularly appealing because the chemical reagents are useful and valuable. We report on the eco-friendly synthesis of MCM-41 nanoporous materials via multi-cycle approach by re-using the non-reacted reagents in supernatant as mother liquor after separating the solid product. This approach was achieved via minimal requirement of chemical compensation where additional fresh reactants were added into the mother liquor followed by pH adjustment after each cycle of synthesis. The solid product of each successive batch was collected and characterized while the non-reacted reagents in supernatant can be recovered and re-used to produce subsequent cycle of MCM-41. The multi-cycle synthesis is demonstrated up to three times in this research. This approach suggests a low cost and eco-friendly synthesis of nanoporous material since less waste is discarded after the product has been collected, and in addition, product yield can be maintained at the high level.

  10. Student performance study: the outcomes of metabolic, molecular and physical-chemical characterization of intestinal tract microbiome on a four mammalian species model

    Directory of Open Access Journals (Sweden)

    Nataša CIBER

    2015-11-01

    Full Text Available Many environmental factors influence the structure of microbial communities, their activity and properties of the environment of the digestive tract. Contrary to constant disturbances, the system provides the basis for energy conversion and thus the long-term stable coexistence of different hosts and their specific intestinal microbiota over geological timescales. Since the methodological approaches proved to be the largest source of systematic errors in comparisons of microbial communities among different organisms of the same species or between different species, we tested a number of methods on samples from different species of mammals in order to verify the feasibility of this approach for future routine analysis of microbiomes:(i analyses of physical-chemical parameters;(iithe metabolic properties of attached, planktonic fractions in comparison to the total;(iiistructure of microbial communities of bacteria and archaea; (ivdata analysis. We used a model of intestinal samples from four species of mammals, encompassing the differences between the various types of intestinal tracts: ruminants and rodents (such as pre- and post- peptic fermentors, omnivores and carnivores. The second purpose of the study was to(iassess the extent of spread of data due to the cooperation of the various operators on the data obtained, and(ii to evaluate the skills of the students to carry out industry-oriented investigations and measurements in 1st year of MSc study Microbiology; and(iii to promote awareness of the importance of routine laboratory work day and the corresponding duties. The results suggest(ithat the operators independently organized and shared tasks;(iisuccessfully completed all methods;(iiiobtain relevant information;(ivcritically evaluated and interpreted within the extent of their knowledge;(v that relative standard deviation(RSD typically could be compared to those of the automated analytical procedures(<10 % and therefore represented the

  11. ReACT!: An Interactive Educational Tool for AI Planning for Robotics

    Science.gov (United States)

    Dogmus, Zeynep; Erdem, Esra; Patogulu, Volkan

    2015-01-01

    This paper presents ReAct!, an interactive educational tool for artificial intelligence (AI) planning for robotics. ReAct! enables students to describe robots' actions and change in dynamic domains without first having to know about the syntactic and semantic details of the underlying formalism, and to solve planning problems using…

  12. Improving Resilience to Emergencies through Advanced Cyber Technologies: the I-REACT project

    Directory of Open Access Journals (Sweden)

    Claudia Maltoni

    2017-08-01

    be equipped with essential tools for early warning and response. At the same time, private companies could leverage specific set of I-REACT components to improve their business, when linked to disaster management. Overall, I-REACT aims to be a European-wide contribution to build more secure and resilient societies to disasters.

  13. Methane reacts with heteropolyacids chemisorbed on silica to produce acetic acid under soft conditions

    KAUST Repository

    Sun, Miao

    2013-01-16

    Selective functionalization of methane at moderate temperature is of crucial economic, environmental, and scientific importance. Here, we report that methane reacts with heteropolyacids (HPAs) chemisorbed on silica to produce acetic acid under soft conditions. Specially, when chemisorbed on silica, H 4SiW12O40, H3PW12O 40, H4SiMo12O40, and H 3PMo12O40 activate the primary C-H bond of methane at room temperature and atmospheric pressure. With these systems, acetic acid is produced directly from methane, in a single step, in the absence of Pd and without adding CO. Extensive surface characterization by solid-state NMR spectroscopy, IR spectroscopy, cyclic voltammetry, and X-ray photoelectron spectroscopy suggests that C-H activation of methane is triggered by the protons in the HPA-silica interface with concerted reduction of the Keggin cage, leading to water formation and hydration of the interface. This is the simplest and mildest way reported to date to functionalize methane. © 2012 American Chemical Society.

  14. Comparison of PDF and Moment Closure Methods in the Modeling of Turbulent Reacting Flows

    Science.gov (United States)

    Norris, Andrew T.; Hsu, Andrew T.

    1994-01-01

    In modeling turbulent reactive flows, Probability Density Function (PDF) methods have an advantage over the more traditional moment closure schemes in that the PDF formulation treats the chemical reaction source terms exactly, while moment closure methods are required to model the mean reaction rate. The common model used is the laminar chemistry approximation, where the effects of turbulence on the reaction are assumed negligible. For flows with low turbulence levels and fast chemistry, the difference between the two methods can be expected to be small. However for flows with finite rate chemistry and high turbulence levels, significant errors can be expected in the moment closure method. In this paper, the ability of the PDF method and the moment closure scheme to accurately model a turbulent reacting flow is tested. To accomplish this, both schemes were used to model a CO/H2/N2- air piloted diffusion flame near extinction. Identical thermochemistry, turbulence models, initial conditions and boundary conditions are employed to ensure a consistent comparison can be made. The results of the two methods are compared to experimental data as well as to each other. The comparison reveals that the PDF method provides good agreement with the experimental data, while the moment closure scheme incorrectly shows a broad, laminar-like flame structure.

  15. The effect of crop sequences on soil microbial, chemical and physical indicators and its relationship with soybean sudden death syndrome (complex of Fusarium species

    Directory of Open Access Journals (Sweden)

    Carolina Perez-Brandan

    2013-12-01

    Full Text Available The effect of crop sequences on soil quality indicators and its relationship with sudden death syndrome (SDS, a complex of Fusarium species was evaluated by physical, chemical, biochemical and molecular techniques. Regarding physical aspects, soybean/maize and maize monoculture exhibited the highest stable aggregate level, with values 41% and 43% higher than in soybean monoculture, respectively, and 133% higher than in bean monoculture. Bulk density (BD was higher in soybean monoculture, being 4% higher than in bean monoculture. The chemical parameters organic matter, total N, P, K, Mg, Ca, and water holding capacity also indicated that soybean/maize and maize monoculture improved soil quality. Fungal and bacterial community fingerprints generated using Terminal Restriction Fragment Length Polymorphism analysis of intergenic transcribed spacer regions of rRNA genes and 16S rRNA genes, respectively, indicated a clear separation between the rotations. Fatty acid profiles evaluated by FAME showed that bean monoculture had higher biomass of Gram (+ bacteria and stress indicators than maize monoculture, while the soybean/maize system showed a significant increase in total microbial biomass (total FAMEs content in comparison with soybean and bean monoculture. The incidence of SDS (Fusarium crassistipitatum was markedly higher (15% under soybean monoculture than when soybean was grown in rotation with maize. In the present work, soil microbial properties were improved under soybean/maize relative to continuous soybean. The improvement of soil health was one of the main causes for the reduction of disease pressure and crop yield improvement due to the benefits that crop rotation produces for soil quality.

  16. The effect of crop sequences on soil microbial, chemical and physical indicators and its relationship with soybean sudden death syndrome (complex of Fusarium species)

    Energy Technology Data Exchange (ETDEWEB)

    Perez-Brandan, C.; Arzeno, J. L.; Huidobro, J.; Conforto, C.; Grumberg, B.; Hilton, S.; Bending, G. D.; Meriles, J. M.; Vargas-Gil, S.

    2014-06-01

    The effect of crop sequences on soil quality indicators and its relationship with sudden death syndrome (SDS, a complex of Fusarium species) was evaluated by physical, chemical, biochemical and molecular techniques. Regarding physical aspects, soybean/maize and maize mono culture exhibited the highest stable aggregate level, with values 41% and 43% higher than in soybean mono culture, respectively, and 133% higher than in bean mono culture. Bulk density (BD) was higher in soybean monoculture, being 4% higher than in bean monoculture. The chemical parameters organic matter, total N, P, K, Mg, Ca, and water holding capacity also indicated that soybean/maize and maize monoculture improved soil quality. Fungal and bacterial community fingerprints generated using Terminal Restriction Fragment Length Polymorphism analysis of intergenic transcribed spacer regions of rRNA genes and 16S rRNA genes, respectively, indicated a clear separation between the rotations. Fatty acid profiles evaluated by FAME showed that bean monoculture had higher biomass of Gram (+) bacteria and stress indicators than maize monoculture, while the soybean/maize system showed a significant increase in total microbial biomass (total FAMEs content) in comparison with soybean and bean monoculture. The incidence of SDS (Fusarium crassistipitatum) was markedly higher (15%) under soybean monoculture than when soybean was grown in rotation with maize. In the present work, soil microbial properties were improved under soybean/maize relative to continuous soybean. The improvement of soil health was one of the main causes for the reduction of disease pressure and crop yield improvement due to the benefits that crop rotation produces for soil quality. (Author)

  17. An LES-PBE-PDF approach for modeling particle formation in turbulent reacting flows

    Science.gov (United States)

    Sewerin, Fabian; Rigopoulos, Stelios

    2017-10-01

    Many chemical and environmental processes involve the formation of a polydispersed particulate phase in a turbulent carrier flow. Frequently, the immersed particles are characterized by an intrinsic property such as the particle size, and the distribution of this property across a sample population is taken as an indicator for the quality of the particulate product or its environmental impact. In the present article, we propose a comprehensive model and an efficient numerical solution scheme for predicting the evolution of the property distribution associated with a polydispersed particulate phase forming in a turbulent reacting flow. Here, the particulate phase is described in terms of the particle number density whose evolution in both physical and particle property space is governed by the population balance equation (PBE). Based on the concept of large eddy simulation (LES), we augment the existing LES-transported probability density function (PDF) approach for fluid phase scalars by the particle number density and obtain a modeled evolution equation for the filtered PDF associated with the instantaneous fluid composition and particle property distribution. This LES-PBE-PDF approach allows us to predict the LES-filtered fluid composition and particle property distribution at each spatial location and point in time without any restriction on the chemical or particle formation kinetics. In view of a numerical solution, we apply the method of Eulerian stochastic fields, invoking an explicit adaptive grid technique in order to discretize the stochastic field equation for the number density in particle property space. In this way, sharp moving features of the particle property distribution can be accurately resolved at a significantly reduced computational cost. As a test case, we consider the condensation of an aerosol in a developed turbulent mixing layer. Our investigation not only demonstrates the predictive capabilities of the LES-PBE-PDF model but also

  18. Coupling genetic and chemical microbiome profiling reveals heterogeneity of archaeome and bacteriome in subsurface biofilms that are dominated by the same archaeal species.

    Directory of Open Access Journals (Sweden)

    Alexander J Probst

    Full Text Available Earth harbors an enormous portion of subsurface microbial life, whose microbiome flux across geographical locations remains mainly unexplored due to difficult access to samples. Here, we investigated the microbiome relatedness of subsurface biofilms of two sulfidic springs in southeast Germany that have similar physical and chemical parameters and are fed by one deep groundwater current. Due to their unique hydrogeological setting these springs provide accessible windows to subsurface biofilms dominated by the same uncultivated archaeal species, called SM1 Euryarchaeon. Comparative analysis of infrared imaging spectra demonstrated great variations in archaeal membrane composition between biofilms of the two springs, suggesting different SM1 euryarchaeal strains of the same species at both aquifer outlets. This strain variation was supported by ultrastructural and metagenomic analyses of the archaeal biofilms, which included intergenic spacer region sequencing of the rRNA gene operon. At 16S rRNA gene level, PhyloChip G3 DNA microarray detected similar biofilm communities for archaea, but site-specific communities for bacteria. Both biofilms showed an enrichment of different deltaproteobacterial operational taxonomic units, whose families were, however, congruent as were their lipid spectra. Consequently, the function of the major proportion of the bacteriome appeared to be conserved across the geographic locations studied, which was confirmed by dsrB-directed quantitative PCR. Consequently, microbiome differences of these subsurface biofilms exist at subtle nuances for archaea (strain level variation and at higher taxonomic levels for predominant bacteria without a substantial perturbation in bacteriome function. The results of this communication provide deep insight into the dynamics of subsurface microbial life and warrant its future investigation with regard to metabolic and genomic analyses.

  19. Climate extreme effects on the chemical composition of temperate grassland species under ambient and elevated CO2: a comparison of fructan and non-fructan accumulators.

    Directory of Open Access Journals (Sweden)

    Hamada AbdElgawad

    Full Text Available Elevated CO2 concentrations and extreme climate events, are two increasing components of the ongoing global climatic change factors, may alter plant chemical composition and thereby their economic and ecological characteristics, e.g. nutritional quality and decomposition rates. To investigate the impact of climate extremes on tissue quality, four temperate grassland species: the fructan accumulating grasses Lolium perenne, Poa pratensis, and the nitrogen (N fixing legumes Medicago lupulina and Lotus corniculatus were subjected to water deficit at elevated temperature (+3°C, under ambient CO2 (392 ppm and elevated CO2 (620 ppm. As a general observation, the effects of the climate extreme were larger and more ubiquitous in combination with elevated CO2. The imposed climate extreme increased non-structural carbohydrate and phenolics in all species, whereas it increased lignin in legumes and decreased tannins in grasses. However, there was no significant effect of climate extreme on structural carbohydrates, proteins, lipids and mineral contents and stoichiometric ratios. In combination with elevated CO2, climate extreme elicited larger increases in fructan and sucrose content in the grasses without affecting the total carbohydrate content, while it significantly increased total carbohydrates in legumes. The accumulation of carbohydrates in legumes was accompanied by higher activity of sucrose phosphate synthase, sucrose synthase and ADP-Glc pyrophosphorylase. In the legumes, elevated CO2 in combination with climate extreme reduced protein, phosphorus (P and magnesium (Mg contents and the total element:N ratio and it increased phenol, lignin, tannin, carbon (C, nitrogen (N contents and C:N, C:P and N:P ratios. On the other hand, the tissue composition of the fructan accumulating grasses was not affected at this level, in line with recent views that fructans contribute to cellular homeostasis under stress. It is speculated that quality losses will

  20. Climate Extreme Effects on the Chemical Composition of Temperate Grassland Species under Ambient and Elevated CO2: A Comparison of Fructan and Non-Fructan Accumulators

    Science.gov (United States)

    Zinta, Gaurav; Van den Ende, Wim; Janssens, Ivan A.; Asard, Han

    2014-01-01

    Elevated CO2 concentrations and extreme climate events, are two increasing components of the ongoing global climatic change factors, may alter plant chemical composition and thereby their economic and ecological characteristics, e.g. nutritional quality and decomposition rates. To investigate the impact of climate extremes on tissue quality, four temperate grassland species: the fructan accumulating grasses Lolium perenne, Poa pratensis, and the nitrogen (N) fixing legumes Medicago lupulina and Lotus corniculatus were subjected to water deficit at elevated temperature (+3°C), under ambient CO2 (392 ppm) and elevated CO2 (620 ppm). As a general observation, the effects of the climate extreme were larger and more ubiquitous in combination with elevated CO2. The imposed climate extreme increased non-structural carbohydrate and phenolics in all species, whereas it increased lignin in legumes and decreased tannins in grasses. However, there was no significant effect of climate extreme on structural carbohydrates, proteins, lipids and mineral contents and stoichiometric ratios. In combination with elevated CO2, climate extreme elicited larger increases in fructan and sucrose content in the grasses without affecting the total carbohydrate content, while it significantly increased total carbohydrates in legumes. The accumulation of carbohydrates in legumes was accompanied by higher activity of sucrose phosphate synthase, sucrose synthase and ADP-Glc pyrophosphorylase. In the legumes, elevated CO2 in combination with climate extreme reduced protein, phosphorus (P) and magnesium (Mg) contents and the total element:N ratio and it increased phenol, lignin, tannin, carbon (C), nitrogen (N) contents and C:N, C:P and N:P ratios. On the other hand, the tissue composition of the fructan accumulating grasses was not affected at this level, in line with recent views that fructans contribute to cellular homeostasis under stress. It is speculated that quality losses will be less

  1. Modeling of turbulent chemical reaction

    Science.gov (United States)

    Chen, J.-Y.

    1995-01-01

    Viewgraphs are presented on modeling turbulent reacting flows, regimes of turbulent combustion, regimes of premixed and regimes of non-premixed turbulent combustion, chemical closure models, flamelet model, conditional moment closure (CMC), NO(x) emissions from turbulent H2 jet flames, probability density function (PDF), departures from chemical equilibrium, mixing models for PDF methods, comparison of predicted and measured H2O mass fractions in turbulent nonpremixed jet flames, experimental evidence of preferential diffusion in turbulent jet flames, and computation of turbulent reacting flows.

  2. Investigation of Na-CO{sub 2} Reaction with Initial Reaction in Various Reacting Surface

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hyun Su; Park, Gunyeop; Kim, Soo Jae; Park, Hyun Sun; Kim, Moo Hwan [POSTECH, Pohang (Korea, Republic of); Wi, Myung-Hwan [KAERI, Daejeon (Korea, Republic of)

    2015-10-15

    The reaction products that cause oxidation and erosion are threaten the heat transfer tubes so that it is necessary to investigate Na-CO{sub 2} reaction according to various experimental parameter. Unlike SWR, Na-CO{sub 2} reaction is more complex to deal with reaction kinetics. Since a comprehensive understanding of Na-CO{sub 2} reaction mechanism is crucial for the safety analysis, the reaction phenomenon under the various conditions was investigated. The current issue is to make a database for developing computational code for CO{sub 2} gas leak situation because it is experimentally difficult to analyze the actual accident situation. Most studies on Na-CO{sub 2} interaction reports that chemical reaction is getting vigorous as temperature increased and reactivity is sensitive as temperature change between 400 .deg. C and 600 .deg. C. Therefore, temperature range is determined based on the operating condition (450 - 500 .deg. C) of KALIMER-600 employed as supercritical CO{sub 2} brayton cycle energy conversion system for Na-CO{sub 2} heat exchanger. And next parameter is sodium surface area which contact between sodium and CO{sub 2} when CO{sub 2} is injected into sodium pool in the accident situation. So, the fundamental surface reaction is experimentally studied in the range of 8 - 12cm{sup 2}. Additionally, it has been reported in recent years that CO{sub 2} Flow rate affects reactivity less significantly and CO{sub 2} flow rate is assumed that 5 SLPM (standard liter per minute) is suitable as a basis for a small leakage. The finally selected control parameters is sodium temperature and reacting surface area with constant CO{sub 2} flow rate. Na-CO{sub 2} reaction test is performed for investigating risk of potential accident which contacts with liquid sodium and CO{sub 2}. Amount of reaction is saturated as time passed because of kept a balance between production of solid phase reaction products and amount of diffusivity. These results contribute to make a

  3. Investigation of Na-CO2 Reaction with Initial Reaction in Various Reacting Surface

    International Nuclear Information System (INIS)

    Kim, Hyun Su; Park, Gunyeop; Kim, Soo Jae; Park, Hyun Sun; Kim, Moo Hwan; Wi, Myung-Hwan

    2015-01-01

    The reaction products that cause oxidation and erosion are threaten the heat transfer tubes so that it is necessary to investigate Na-CO 2 reaction according to various experimental parameter. Unlike SWR, Na-CO 2 reaction is more complex to deal with reaction kinetics. Since a comprehensive understanding of Na-CO 2 reaction mechanism is crucial for the safety analysis, the reaction phenomenon under the various conditions was investigated. The current issue is to make a database for developing computational code for CO 2 gas leak situation because it is experimentally difficult to analyze the actual accident situation. Most studies on Na-CO 2 interaction reports that chemical reaction is getting vigorous as temperature increased and reactivity is sensitive as temperature change between 400 .deg. C and 600 .deg. C. Therefore, temperature range is determined based on the operating condition (450 - 500 .deg. C) of KALIMER-600 employed as supercritical CO 2 brayton cycle energy conversion system for Na-CO 2 heat exchanger. And next parameter is sodium surface area which contact between sodium and CO 2 when CO 2 is injected into sodium pool in the accident situation. So, the fundamental surface reaction is experimentally studied in the range of 8 - 12cm 2 . Additionally, it has been reported in recent years that CO 2 Flow rate affects reactivity less significantly and CO 2 flow rate is assumed that 5 SLPM (standard liter per minute) is suitable as a basis for a small leakage. The finally selected control parameters is sodium temperature and reacting surface area with constant CO 2 flow rate. Na-CO 2 reaction test is performed for investigating risk of potential accident which contacts with liquid sodium and CO 2 . Amount of reaction is saturated as time passed because of kept a balance between production of solid phase reaction products and amount of diffusivity. These results contribute to make a database for the SFR safety analysis and additional experiments are needed

  4. Influence of tree species on the herbaceous understory and soil chemical characteristics in a silvopastoral system in semi-arid northeastern Brazil

    Directory of Open Access Journals (Sweden)

    R. S. C. Menezes

    1999-12-01

    Full Text Available Studies from some semi-arid regions of the world have shown the beneficial effect of trees in silvopastoral systems, by promoting the formation of resource islands and increasing the sustainability of the system. No data are available in this respect for tree species of common occurrence in semi-arid Northeastern Brazil. In the present study, conducted in the summer of 1996, three tree species (Zyziphus joazeiro, Spondias tuberosa and Prosopis juliflora: found within Cenchrus ciliaris pastures were selected to evaluate differences on herbaceous understory and soil chemical characteristics between samples taken under the tree canopy and in open grass areas. Transects extending from the tree trunk to open grass areas were established, and soil (0-15 cm and herbaceous understory (standing live biomass in 1 m² plots samples were taken at 0, 25, 50, 100, 150 and 200% of the average canopy radius (average radius was 6.6 ± 0.5, 4.5 ± 0.5, and 5.3 ± 0.8 m for Z. joazeiro, P. juliflora, and S. tuberosa , respectively. Higher levels of soil C, N, P, Ca, Mg, K, and Na were found under the canopies of Z. joazeiro and P. juliflora: trees, as compared to open grass areas. Only soil Mg organic P were higher under the canopies of S. tuberosa trees, as compared to open grass areas. Herbaceous understory biomass was significantly lower under the canopy of S. tuberosa and P. juliflora trees (107 and 96 g m-2, respectively relatively to open grass areas (145 and 194 g m-2. No herbaceous biomass differences were found between Z. joazeiro canopies and open grass areas (107 and 87 g m-2, respectively. Among the three tree species studied, Z. joazeiro was the one that presented the greatest potential for use in a silvopastoral system at the study site, since it had a larger nutrient stock in the soil without negatively affecting herbaceous understory biomass, relatively to open grass areas.

  5. Species and life-history affects the utility of otolith chemical composition to determine natal stream-of-origin in Pacific salmon

    Science.gov (United States)

    Zimmerman, Christian E.; Swanson, Heidi K.; Volk, Eric C.; Kent, Adam J.R.

    2013-01-01

    To test the utility of otolith chemical composition as a tool for determining the natal stream of origin for salmon, we examined water chemistry and otoliths of juvenile and adult Chum Salmon Oncorhynchus keta and Coho Salmon O. kisutch from three watersheds (five rivers) in the Norton Sound region of Alaska. The two species are characterized by different life histories: Coho Salmon rear in freshwater for up to 3 years, whereas Chum Salmon emigrate from freshwater shortly after emergence. We used laser ablation (LA) inductively coupled plasma (ICP) mass spectrometry (MS) to quantify element: Ca ratios for Mg, Mn, Zn, Sr, and Ba, and we used multicollector LA-ICP-MS to determine 87Sr:86Sr ratios in otolith regions corresponding to the period of freshwater residence. Significant differences existed in both water and otolith elemental composition, suggesting that otolith composition could be used to discriminate the natal origin of Coho Salmon and Chum Salmon but only when 87Sr:86Sr ratios were included in the discriminant function analyses. The best discriminant model included 87Sr:86Sr ratios, and without 87Sr:86Sr ratios it was difficult to discriminate among watersheds and rivers. Classification accuracy was 80% for Coho Salmon and 68% for Chum Salmon, indicating that this method does not provide sufficient sensitivity to estimate straying rates of Pacific salmon at the scale we studied.

  6. The influence of physical and chemical parameters on the extinction of the god fish (Tor duoronensis) species: case study in Balong Dalem Kuningan district

    Science.gov (United States)

    Abidin, Z.; Marwoto, P.; Iswari, R. S.

    2018-03-01

    Tor douronensis (God Fish) species are endemic freshwater fish that only live in Kuningan District. Originally these fish scattered in the pool Cigugur, Cibulan, Balong Kambang, Darma Loka and Balong Dalem. However, since 2006 the god fish that existed in Balong Dalem extinct. This study aims to analyze the possible factors causing extinction of the god fish in situ Balong Dalem. The study was conducted during May 2017. The results showed that there were 11 phytoplankton and 13 genera of Gomphonema, Stigeoclonium, Desmidium, Closterium, Navicula, Spirulina, Phormidium, Melosira, Gloeotrichia, Oedogonium, Hyalodiscus, Moscocrocis and Cladophora. While zooplankton found 3 genus of Cyclops, Rotifera and Tanypus. The results showed that the abundance, diversity and uniformity of zooplankton correlated positively with pH, temperature, DO and water flow but not with others. Condition of water quality (physical-chemical parameter) Balong Dalem in bad condition, low productivity and labile. Condition of substrate base there Balong Dalem in the form of sand and fine mud. All of these conditions caused the extinction of Tor douronensis in situ Balong Dalem.

  7. Seasonal Variation in the Chemical Composition and Antimicrobial Activity of Volatile Oils of Three Species of Leptospermum (Myrtaceae Grown in Brazil

    Directory of Open Access Journals (Sweden)

    Antonio Lelis Pinheiro

    2011-01-01

    Full Text Available This study investigates the seasonal variation of three species of Leptospermum (Myrtaceae grown in Brazil. The chemical composition of the volatile oils of L. flavescens and L. petersonii did not show any significant seasonal variation in the major components, while for Leptospermum madidum subsp. sativum the levels of major constituents of the volatile oils varied with the harvest season. Major fluctuations in the composition of L. madidum subsp. sativum oil included α-pinene (0–15.2%, β-pinene (0.3–18.5%, α-humulene (0.8–30%, 1,8-cineole (0.4–7.1% and E-caryophyllene (0.4–11.9%. Levels of β-pinene (0.3–5.6%, terpinen-4-ol (4.7–7.2% and nerolidol (55.1–67.6% fluctuated seasonally in the L. flavescens oil. In L. petersonii, changes were noted for geranial (29.8–32.8%, citronellal (26.5–33.9% and neral (22.7–23.5%. The activity of the volatile oils against the tested bacteria differed, depending on season the oils were obtained. In general, the volatile oils were more active against Gram-positive bacteria.

  8. Study of transport and micro-structural properties of magnesium di-boride strand under react and bend mode and bend and react mode

    International Nuclear Information System (INIS)

    Kundu, Ananya; Das, Subrat Kumar; Bano, Anees; Pradhan, Subrata

    2015-01-01

    I-V characterization of commercial multi-filamentary Magnesium Di-Boride (MgB 2 ) wire of diameter 0.83 mm were studied in cryocooler based self-field characterization system under both react and bent mode and bent and react mode for a range of temperature 6 K - 25 K. This study is of practical technical relevance where the heat treatment of the superconducting wire makes the sample less flexible for winding in magnet and in other applications. There are limited reported data, available on degradation of MgB 2 wire with bending induced strain in react and wind and wind and react method. In the present work the bending diameter were varied from 80 mm to 20 mm in the interval of 10 mm change of bending diameter and for each case critical current (Ic) of the strand is measured for the above range of temperature. An ETP copper made customized sample holder for mounting the MgB 2 strand was fabricated and is thermally anchored to the cooling stage of the cryocooler. It is seen from the experimental data that in react and bent mode the critical current degrades from 105 A to 87 A corresponding to bending diameter of 80 mm and 20 mm respectively. The corresponding bending strain was analytically estimated and compared with the simulation result. It is also observed that in react and bent mode, the degradation of the transport property of the strand is less as compared to react and bent mode. For bent and react mode in the same sample, the critical current (Ic) was measured to be ∼145 A at 15 K for bending diameter of 20 mm. Apart from studying the bending induced strain on MgB 2 strand, the tensile test of the strand at RT was carried out. The electrical characterizations of the samples were accompanied by the microstructure analyses of the bent strand to examine the bending induced degradation in the grain structure of the strand. All these experimental findings are expected to be used as input to fabricate prototype MgB 2 based magnet. (author)

  9. Method for aquatic multiple species toxicant testing: acute toxicity of 10 chemicals to 5 vertebrates and 2 invertebrates. [Pimephales promelas; Carassius auratus; Ictalurus punctatus; Lepomis macrochirus; Salmo gairdneri; Orconectes immunis; Aplexa hypnorum

    Energy Technology Data Exchange (ETDEWEB)

    Phipps, G.L.; Holcombe, G.W.

    1985-01-01

    A method was developed to simultaneously ascertain 96 h LC/sub 50/ values for seven freshwater species in a single flow through test with measured concentrations. It allows interspecific comparisons, easy determination of the most sensitive species, and cuts cost of labor, materials and chemical analysis for measured concentration tests. Species tested included fathead minnows Pimephales promelas, goldfish Carassius auratus, channel catfish Ictalurus punctatus, bluegill Lepomis macrochirus, rainbow trout Salmo gairdneri, crayfish Orconectes immunis and snails Aplexa hypnorum. Compounds tested were pentachlorophenol, 2-chloroethanol, 2,4-pentanedione, hexachloroethane, ..cap alpha..-bromo-2',5'-dimethoxyacetophenone, benzaldehyde, 1,3-dichloro-4,6-dinitro-benzene, dursban, sevin and cadmium chloride. The LC/sub 50/ values from these multiple species tests compared favourably with those determined using single species tests at this laboratory, usually within 20%.

  10. Developing Dynamic Single Page Web Applications Using Meteor : Comparing JavaScript Frameworks: Blaze and React

    OpenAIRE

    Yetayeh, Asabeneh

    2017-01-01

    This paper studies Meteor which is a JavaScript full-stack framework to develop interactive single page web applications. Meteor allows building web applications entirely in JavaScript. Meteor uses Blaze, React or AngularJS as a view layer and Node.js and MongoDB as a back-end. The main purpose of this study is to compare the performance of Blaze and React. A multi-user Blaze and React web applications with similar HTML and CSS were developed. Both applications were deployed on Heroku’s w...

  11. Streptococcus sinensis may react with Lancefield group F antiserum.

    Science.gov (United States)

    Woo, Patrick C Y; Teng, Jade L L; Leung, Kit-wah; Lau, Susanna K P; Tse, Herman; Wong, Beatrice H L; Yuen, Kwok-yung

    2004-11-01

    Lancefield group F streptococci have been found almost exclusively as members of the 'Streptococcus milleri' group, although they have been reported very occasionally in some other streptococcal species. Among 302 patients with bacteraemia caused by viridans streptococci over a 6-year period, three cases were caused by Streptococcus sinensis (type strain HKU4T, HKU5 and HKU6). All three patients had infective endocarditis complicating their underlying chronic rheumatic heart diseases. Gene sequencing showed no base differences between the 16S rRNA gene sequences of HKU5 and HKU6 and that of HKU4T. All three strains were Gram-positive, non-spore-forming cocci arranged in chains. All grew on sheep blood agar as alpha-haemolytic, grey colonies of 0.5-1 mm in diameter after 24 h incubation at 37 degrees C in ambient air. Lancefield grouping revealed that HKU5 and HKU6 were Lancefield group F, but HKU4T was non-groupable with Lancefield groups A, B, C, D, F or G antisera. HKU4T was identified by the Vitek system (GPI), API system (20 STREP) and ATB system (ID32 STREP) as 99 % Streptococcus intermedius, 51.3 % S. intermedius and 99.9 % Streptococcus anginosus, respectively. Using the same tests, HKU5 was identified as 87 % Streptococcus sanguinis/Streptococcus gordonii, 59 % Streptococcus salivarius and 99.6 % S. anginosus, respectively, and HKU6 as 87 % S. sanguinis/S. gordonii, 77 % Streptococcus pneumoniae and 98.3 % S. anginosus, respectively. The present data revealed that a proportion of Lancefield group F streptococci could be S. sinensis. Lancefield group F streptococci should not be automatically reported as 'S. milleri'.

  12. Temporal-spatial characteristics and source apportionment of PM2.5 as well as its associated chemical species in the Beijing-Tianjin-Hebei region of China.

    Science.gov (United States)

    Gao, Jiajia; Wang, Kun; Wang, Yong; Liu, Shuhan; Zhu, Chuanyong; Hao, Jiming; Liu, Huanjia; Hua, Shenbing; Tian, Hezhong

    2018-02-01

    PM 2.5 and its major chemical compositions were sampled and analyzed in January, April, July and October of 2014 at Beijing (BJ), Tianjin (TJ), Langfang (LF) and Baoding (BD) in order to probe the temporal and spatial characteristics as well as source apportionment of PM 2.5 in the Beijing-Tianjin-Hebei (BTH) region. The results showed that PM 2.5 pollution was severe in the BTH region. The average annual concentrations of PM 2.5 at four sampling sites were in the range of 126-180 μg/m 3 , with more than 95% of sampling days exceeding 35 μg/m 3 , the limit ceiling of average annual concentration of PM 2.5 regulated in the Chinese National Ambient Air Quality Standards (GB3095-2012). Additionally, concentrations of PM 2.5 and its major chemical species were seasonally dependent and demonstrated spatially similar variation characteristics in the BTH region. Concentration of toxic heavy metals, such as As, Cd, Cr, Cu, Mn, Ni, Pb, Sb, Se, and Zn, were higher in winter and autumn. Secondary inorganic ions (SO 4 2- , NO 3 - , and NH 4 + ) were the three-major water-soluble inorganic ions (WSIIs) of PM 2.5 and their mass ratios to PM 2.5 were higher in summer and autumn. The organic carbon (OC) and elemental carbon (EC) concentrations were lower in spring and summer than in autumn and winter. Five factors were selected in Positive Matrix Factorization (PMF) model analysis, and the results showed that PM 2.5 pollution was dominated by vehicle emissions in Beijing, combustion emissions including coal burning and biomass combustion in Langfang and Baoding, and soil and construction dust emissions in Tianjin, respectively. The air mass that were derived from the south and southeast local areas around BTH regions reflected the features of short-distant and small-scale air transport. Shandong, Henan, and Hebei were identified the major potential sources-areas of secondary aerosol emissions to PM 2.5 . Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. Source apportionment of carbonaceous chemical species to fossil fuel combustion, biomass burning and biogenic emissions by a coupled radiocarbon-levoglucosan marker method

    Science.gov (United States)

    Salma, Imre; Németh, Zoltán; Weidinger, Tamás; Maenhaut, Willy; Claeys, Magda; Molnár, Mihály; Major, István; Ajtai, Tibor; Utry, Noémi; Bozóki, Zoltán

    2017-11-01

    An intensive aerosol measurement and sample collection campaign was conducted in central Budapest in a mild winter for 2 weeks. The online instruments included an FDMS-TEOM, RT-OC/EC analyser, DMPS, gas pollutant analysers and meteorological sensors. The aerosol samples were collected on quartz fibre filters by a low-volume sampler using the tandem filter method. Elemental carbon (EC), organic carbon (OC), levoglucosan, mannosan, galactosan, arabitol and mannitol were determined, and radiocarbon analysis was performed on the aerosol samples. Median atmospheric concentrations of EC, OC and PM2.5 mass were 0.97, 4.9 and 25 µg m-3, respectively. The EC and organic matter (1.6 × OC) accounted for 4.8 and 37 %, respectively, of the PM2.5 mass. Fossil fuel (FF) combustion represented 36 % of the total carbon (TC = EC + OC) in the PM2.5 size fraction. Biomass burning (BB) was a major source (40 %) for the OC in the PM2.5 size fraction, and a substantial source (11 %) for the PM10 mass. We propose and apply here a novel, straightforward, coupled radiocarbon-levoglucosan marker method for source apportionment of the major carbonaceous chemical species. The contributions of EC and OC from FF combustion (ECFF and OCFF) to the TC were 11.0 and 25 %, respectively, EC and OC from BB (ECBB and OCBB) were responsible for 5.8 and 34 %, respectively, of the TC, while the OC from biogenic sources (OCBIO) made up 24 % of the TC. The overall relative uncertainty of the OCBIO and OCBB contributions was assessed to be up to 30 %, while the relative uncertainty for the other apportioned species is expected to be below 20 %. Evaluation of the apportioned atmospheric concentrations revealed some of their important properties and relationships among them. ECFF and OCFF were associated with different FF combustion sources. Most ECFF was emitted by vehicular road traffic, while the contribution of non-vehicular sources such as domestic and industrial heating or cooking using gas, oil or coal

  14. Chemical and biological characterisation of solvent extracts and essential oils from leaves and fruit of two Australian species of Pittosporum (Pittosporaceae) used in aboriginal medicinal practice.

    Science.gov (United States)

    Sadgrove, Nicholas John; Jones, Graham Lloyd

    2013-02-13

    antimicrobial activity whilst the other chemotype had only moderate antimicrobial activity against the three microbial species investigated here. This result may support the occurrence of geographical specificity with regard to ethnopharmacological use. Antimicrobial activity screening of the solvent extracts from Pittosporum angustifolium revealed the leaves to be superior to fruit, with water being the most suitable extraction solvent. To the best of our knowledge, this study constitutes the first time essential oils, and solvent extracts from the fruits of Pittosporum angustifolium, have been examined employing comprehensive chemical and biological analysis. The essential oil composition presented in this paper, includes components with structural similarity as chemosemiotic compounds involved in mother-infant identification, which may have significance with regard to traditional applications as a lactagogue. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  15. Methane reacts with heteropolyacids chemisorbed on silica to produce acetic acid under soft conditions

    KAUST Repository

    Sun, Miao; Abou-Hamad, Edy; Rossini, Aaron J.; Zhang, Jizhe; Lesage, Anne; Zhu, Haibo; Pelletier, Jeremie; Emsley, Lyndon; Caps, Valerie; Basset, Jean-Marie

    2013-01-01

    Selective functionalization of methane at moderate temperature is of crucial economic, environmental, and scientific importance. Here, we report that methane reacts with heteropolyacids (HPAs) chemisorbed on silica to produce acetic acid under soft

  16. Rule-Based Multidisciplinary Tool for Unsteady Reacting Real-Fluid Flows, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — A design and analysis computational tool is proposed for simulating unsteady reacting flows in combustor devices used in reusable launch vehicles. Key aspects...

  17. Investigation of a Monte Carlo model for chemical reactions

    International Nuclear Information System (INIS)

    Hamm, R.N.; Turner, J.E.; Stabin, M.G.

    1998-01-01

    Monte Carlo computer simulations are in use at a number of laboratories for calculating time-dependent yields, which can be compared with experiments in the radiolysis of water. We report here on calculations to investigate the validity and consistency of the procedures used for simulating chemical reactions in our code, RADLYS. Model calculations were performed of the rate constants themselves. The rates thus determined showed an expected rapid decline over the first few hundred ps and a very gradual decline thereafter out to the termination of the calculations at 4.5 ns. Results are reported for different initial concentrations and numbers of reactive species. Generally, the calculated rate constants are smallest when the initial concentrations of the reactants are largest. It is found that inhomogeneities that quickly develop in the initial random spatial distribution of reactants persist in time as a result of subsequent chemical reactions, and thus conditions may poorly approximate those assumed from diffusion theory. We also investigated the reaction of a single species of one type placed among a large number of randomly distributed species of another type with which it could react. The distribution of survival times of the single species was calculated by using three different combinations of the diffusion constants for the two species, as is sometimes discussed in diffusion theory. The three methods gave virtually identical results. (orig.)

  18. KEEFEKTIFAN STRATEGI REACT DITINJAU DARI PRESTASI BELAJAR, KEMAMPUAN PENYELESAIAN MASALAH, KONEKSI MATEMATIS, SELF EFFICACY

    Directory of Open Access Journals (Sweden)

    Runtyani Irjayanti Putri

    2015-11-01

    Full Text Available Penelitian ini bertujuan untuk: (1 mendeskripsikan keefektifan strategi pembelajaran REACT pada pembelajaran turunan fungsi ditinjau dari prestasi belajar matematika, kemampuan penyelesaian masalah matematis, kemampuan koneksi matematis, dan Self efficacy siswa SMA Negeri 4 Magelang, (2 menentukan strategi pembelajaran yang lebih efektif diantara strategi REACT dan pembelajaran konvensional pada pembelajaran turunan fungsi ditinjau dari aspek prestasi belajar matematika, kemampuan penyelesaian masalah matematis, kemampuan koneksi matematis, dan Self efficacy siswa SMA Negeri 4 Magelang. Penelitian ini adalah penelitian quasi experiment. Teknik pengumpulan data yang digunakan adalah teknik tes dan nontes. Teknik analisis data yang digunakan adalah uji one sample t-test, uji T2 Hotelling’s, dan uji t-Bonferroni. Hasil penelitian menunjukkan bahwa: (1 strategi pembelajaran REACT efektif pada pembelajaran turunan fungsi ditinjau dari prestasi belajar matematika, kemampuan penyelesaian masalah matematis, kemampuan koneksi matematis, dan Self efficacy siswa SMA Negeri 4 Magelang, dan (2 strategi pembelajaran REACT lebih efektif daripada pembelajaran konvensional pada pembelajaran turunan fungsi ditinjau dari aspek prestasi belajar matematika, kemampuan penyelesaian masalah matematis, kemampuan koneksi matematis, dan Self efficacy siswa SMA Negeri 4 Magelang. Kata Kunci: strategi REACT, prestasi belajar, kemampuan penyelesaian masalah matematis, kemampuan koneksi matematis, dan Self efficacy siswa SMA   THE EFFECTIVENESS OF REACT STRATEGY VIEWED FROM LEARNING ACHIEVEMENT, PROBLEM SOLVING ABILITY, MATHEMATICAL CONNECTION, SELF EFFICACY Abstract The aims of this study are to: (1 to describe the effectiveness of the REACT strategy viewed from Mathematics Learning Achievement, Mathematics Problem Solving Ability, Mathematics Connection Ability, and Student Self efficacy of State Senior High School 4 Magelang Students, and (2 determine a more effective

  19. House dust mite (Der p 10) and crustacean allergic patients may react to food containing Yellow mealworm proteins.

    Science.gov (United States)

    Verhoeckx, Kitty C M; van Broekhoven, Sarah; den Hartog-Jager, Constance F; Gaspari, Marco; de Jong, Govardus A H; Wichers, Harry J; van Hoffen, Els; Houben, Geert F; Knulst, André C

    2014-03-01

    Due to the imminent growth of the world population, shortage of protein sources for human consumption will arise in the near future. Alternative and sustainable protein sources (e.g. insects) are being explored for the production of food and feed. In this project, the safety of Yellow mealworms (Tenebrio molitor L.) for human consumption was tested using approaches as advised by the European Food Safety Authority for allergenicity risk assessment. Different Yellow mealworm protein fractions were prepared, characterised, and tested for cross-reactivity using sera from patients with an inhalation or food allergy to biologically related species (House dust mite (HDM) and crustaceans) by immunoblotting and basophil activation. Furthermore, the stability was investigated using an in vitro pepsin digestion test. IgE from HDM- and crustacean allergic patients cross-reacted with Yellow mealworm proteins. This cross-reactivity was functional, as shown by the induction of basophil activation. The major cross-reactive proteins were identified as tropomyosin and arginine kinase, which are well known allergens in arthropods. These proteins were moderately stable in the pepsin stability test. Based on these cross-reactivity studies, there is a realistic possibility that HDM- and crustacean allergic patients may react to food containing Yellow mealworm proteins. Copyright © 2014 Elsevier Ltd. All rights reserved.

  20. Influence of haze pollution on water-soluble chemical species in PM2.5 and size-resolved particles at an urban site during fall.

    Science.gov (United States)

    Yu, Geun-Hye; Zhang, Yan; Cho, Sung-Yong; Park, Seungshik

    2017-07-01

    To investigate the influence of haze on the chemical composition and formation processes of ambient aerosol particles, PM 2.5 and size-segregated aerosol particles were collected daily during fall at an urban site of Gwangju, Korea. During the study period, the total concentration of secondary ionic species (SIS) contributed an average of 43.9% to the PM 2.5 , whereas the contribution of SIS to the PM 2.5 during the haze period was 62.3%. The NO 3 - and SO 4 2- concentrations in PM 2.5 during the haze period were highly elevated, being 13.4 and 5.0 times higher than those during non-haze period, respectively. The PM, NO 3 - , SO 4 2- , oxalate, water-soluble organic carbon (WSOC), and humic-like substances (HULIS) had tri-modal size distributions peaks at 0.32, 1.0, and 5.2μm during the non-haze and haze periods. However, during the non-haze period they exhibited dominant size distributions at the condensation mode peaking at 0.32μm, while on October 21 when the heaviest haze event occurred, they had predominant droplet mode size distributions peaking at 1.00μm. Moreover, strong correlations of WSOC and HULIS with SO 4 2- , oxalate, and K + at particle sizes of <1.8μm indicate that secondary processes and emissions from biomass burning could be responsible for WSOC and HULIS formations. It was found that the factors affecting haze formation could be the local stable synoptic conditions, including the weak surface winds and high surface pressures, the long-range transportation of haze from eastern China and upwind regions of the Korean peninsula, as well as the locally emitted and produced aerosol particles. Copyright © 2016. Published by Elsevier B.V.

  1. Approximate method for stochastic chemical kinetics with two-time scales by chemical Langevin equations

    International Nuclear Information System (INIS)

    Wu, Fuke; Tian, Tianhai; Rawlings, James B.; Yin, George

    2016-01-01

    The frequently used reduction technique is based on the chemical master equation for stochastic chemical kinetics with two-time scales, which yields the modified stochastic simulation algorithm (SSA). For the chemical reaction processes involving a large number of molecular species and reactions, the collection of slow reactions may still include a large number of molecular species and reactions. Consequently, the SSA is still computationally expensive. Because the chemical Langevin equations (CLEs) can effectively work for a large number of molecular species and reactions, this paper develops a reduction method based on the CLE by the stochastic averaging principle developed in the work of Khasminskii and Yin [SIAM J. Appl. Math. 56, 1766–1793 (1996); ibid. 56, 1794–1819 (1996)] to average out the fast-reacting variables. This reduction method leads to a limit averaging system, which is an approximation of the slow reactions. Because in the stochastic chemical kinetics, the CLE is seen as the approximation of the SSA, the limit averaging system can be treated as the approximation of the slow reactions. As an application, we examine the reduction of computation complexity for the gene regulatory networks with two-time scales driven by intrinsic noise. For linear and nonlinear protein production functions, the simulations show that the sample average (expectation) of the limit averaging system is close to that of the slow-reaction process based on the SSA. It demonstrates that the limit averaging system is an efficient approximation of the slow-reaction process in the sense of the weak convergence.

  2. Modeling study of rarefied gas effects on hypersonic reacting stagnation flows

    Science.gov (United States)

    Wang, Zhihui; Bao, Lin

    2014-12-01

    Recent development of the near space hypersonic sharp leading vehicles has raised a necessity to fast and accurately predict the aeroheating in hypersonic rarefied flows, which challenges our understanding of the aerothermodynamics and aerothermochemistry. The present flow and heat transfer problem involves complex rarefied gas effects and nonequilibrium real gas effects which are beyond the scope of the traditional prediction theory based on the continuum hypothesis and equilibrium assumption. As a typical example, it has been found that the classical Fay-Riddell equation fails to predict the stagnation point heat flux, when the flow is either rarefied or chemical nonequilibrium. In order to design a more general theory covering the rarefied reacting flow cases, an intuitive model is proposed in this paper to describe the nonequilibrium dissociation-recombination flow along the stagnation streamline towards a slightly blunted nose in hypersonic rarefied flows. Some characteristic flow parameters are introduced, and based on these parameters, an explicitly analytical bridging function is established to correct the traditional theory to accurately predict the actual aeroheating performance. It is shown that for a small size nose in medium density flows, the flow at the outer edge of the stagnation point boundary layer could be highly nonequilibrium, and the aeroheating performance is distinguished from that of the big blunt body reentry flows at high altitudes. As a result, when the rarefied gas effects and the nonequilibrium real gas effects are both significant, the classical similarity law could be questionable, and it is inadequate to directly analogize results from the classical blunt body reentry problems to the present new generation sharp-leading vehicles. In addition, the direct simulation Monte Carlo method is also employed to validate the conclusion.

  3. Large Eddy Simulation of Spatially Developing Turbulent Reacting Shear Layers with the One-Dimensional Turbulence Model

    Science.gov (United States)

    Hoffie, Andreas Frank

    model. The chemical reaction is simulated with a global single-step, second-order equilibrium reaction with an Arrhenius reaction rate. The two benchmark cases of constant density reacting and variable density non-reacting shear layers used to determine ODT parameters yield perfect agreement with regards to first and second-order flow statistics as well as shear layer growth rate. The variable density non-reacting shear layer also serves as a testing case for the LES-ODT model to simulate passive scalar mixing. The variable density, reacting shear layer cases only agree reasonably well and indicate that more work is necessary to improve variable density coupling of ODT and LES. The disagreement is attributed to the fact that the ODT filtered density is kept constant across the Runge-Kutta steps. Furthermore, a more in-depth knowledge of large scale and subgrid turbulent kinetic energy (TKE) spectra at several downstream locations as well as TKE budgets need to be studied to obtain a better understanding about the model as well as about the flow under investigation. The local Reynolds number based on the one-percent thickness at the exit is Redelta ≈ 5300, for the constant density reacting and for the variable density non-reacting case. For the variable density reacting shear layer, the Reynolds number based on the 1% thickness is Redelta ≈ 2370. The variable density reacting shear layers show suppressed growth rates due to density variations caused by heat release. This has also been reported in literature. A Lewis number parameter study is performed to extract non-unity Lewis number effects. An increase in the Lewis number leads to a further suppression of the growth rate, however to an increase spread of second-order flow statistics. Major focus and challenge of this work is to improve and advance the three-dimensional coupling of the one-dimensional ODT domains while keeping the solution correct. This entails major restructuring of the model. The turbulent

  4. Cross-reacting and heterospecific monoclonal antibodies produced against arabis mosaic nepovirus.

    Science.gov (United States)

    Frison, E A; Stace-Smith, R

    1992-10-01

    Monoclonal antibodies (MAbs) were produced against arabis mosaic nepovirus (AMV). A hybridoma screening procedure was applied which involved the testing of culture supernatants, before the hybridomas were cloned to single cell lines, for their reaction with eight nepoviruses [AMV, cherry leafroll virus (CLRV), grapevine fanleaf virus (GFLV), peach rosette mosaic virus, raspberry ringspot virus (RRSV), tobacco ringspot virus, tomato black ring virus (TBRV) and tomato ringspot virus]. In addition to AMV-specific MAbs, this screening technique has allowed the selection of two cross-reacting MAbs: one reacting with AMV and GFLV, and one reacting with AMV and RRSV. This is the first report of MAbs cross-reacting with these nepoviruses. In addition, five heterospecific MAbs (HS-MAbs) could be selected: two reacting with RRSV, two with CLRV and one with TBRV. The usefulness of the screening technique that was applied for the selection of cross-reacting MAbs and HS-MAbs, and the potential use of such antibodies are discussed.

  5. Birefringence characteristics in sperm heads allow for the selection of reacted spermatozoa for intracytoplasmic sperm injection.

    Science.gov (United States)

    Gianaroli, Luca; Magli, M Cristina; Ferraretti, Anna P; Crippa, Andor; Lappi, Michela; Capitani, Serena; Baccetti, Baccio

    2010-02-01

    To verify clinical outcome after injection of spermatozoa that have undergone the acrosome reaction (reacted spermatozoa) vs. those still having an intact acrosome (nonreacted spermatozoa). Prospective, randomized study. Reproductive Medicine Unit, Italian Society for the Study of Reproductive Medicine, Bologna, Italy. According to a prospective randomization including 71 couples with severe male factor infertility, intracytoplasmic sperm injection (ICSI) was performed under polarized light that permitted analysis of the pattern of birefringence in the sperm head. Twenty-three patients had their oocytes injected with reacted spermatozoa, 26 patient's oocytes were injected with nonreacted spermatozoa, and in 22 patients both reacted and nonreacted spermatozoa were injected. Intracytoplasmic sperm injection was performed under polarized light to selectively inject acrosome-reacted and acrosome-nonreacted spermatozoa. Rates of fertilization, cleavage, pregnancy, implantation, and ongoing implantation. There was no effect on the fertilizing capacity and embryo development of either type of sperm, whereas the implantation rate was higher in oocytes injected with reacted spermatozoa (39.0%) vs. those injected with nonreacted spermatozoa (8.6%). The implantation rate was 24.4% in the group injected with both reacted and nonreacted spermatozoa. The delivery rate per cycle followed the same trend. Spermatozoa that have undergone the acrosome reaction seem to be more prone to supporting the development of viable ICSI embryos. Copyright 2010 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.

  6. THE CANOPY EFFECTS OF Prosopis juliflora (DC. AND Acacia tortilis (HAYNE TREES ON HERBACEOUS PLANTS SPECIES AND SOIL PHYSICO-CHEMICAL PROPERTIES IN NJEMPS FLATS, KENYA

    Directory of Open Access Journals (Sweden)

    Henry C. Kahi

    2009-03-01

    Full Text Available The canopy effects of an exotic and indigenous tree species on soil properties and understorey herbaceous plant species were investigated on the Njemps Flats, Baringo district, Kenya. Samples of soil and herbaceous plant species were obtained within the canopies of systematically selected P. juliflora (exotic and A. tortilis (indigenous trees, and from adjacent open areas. Standing biomass, frequency and cover of understorey plant species were significantly (P

  7. Reacting fluids analysis and polluting emissions; Analisis de fluidos reactivos y emisiones contaminantes

    Energy Technology Data Exchange (ETDEWEB)

    Munoz Ledo, Ramon; Ley Koo, Marcos [Instituto de Investigaciones Electricas, Cuernavaca (Mexico); Varela Ham, Ruben [Universidad Autonoma Metropolitana, Mexico, D. F. (Mexico)

    1993-12-31

    A problem is set up of a reacting flow which occurs in a gas exhausting duct, which is boiled down to a problem of initial conditions (temperature, pressure and concentration of species) freeing the selection of reaction mechanisms. Through some pre-established algorithms calculation routines can be programmed in specific problems of chemistry kinetics. With the calculation routines set forth in base of the selected mechanism, the temperature, pressure, etc., conditions, a general program is obtained containing the differential equations for the mechanisms, and with its solution, with a certain degree of uncertainty, the gases at a duct outlet can be predicted. The exhaust gases will carry unburned particles and products that can be polluting or not. If we vary the working conditions, we can find the optimum values to work with equipment that produces exhaust gases, anticipating with it the more efficient utilization of the equipment and the energy with the least possible pollution. [Espanol] Se plantea un problema de un flujo reactivo que se lleva a cabo en un ducto de salida de gases de escape, para lo cual se reduce a un problema de condiciones iniciales (temperatura, presion y concentracion de especies), y dejando en libertad la seleccion de mecanismos de reaccion. Mediante algunos algoritmos preestablecidos se pueden programar las rutinas de calculo en problemas especificos de cinetica quimica. Con las rutinas de calculo planteadas en base al mecanismo seleccionado, las condiciones de temperatura, presion, etc. se obtiene un programa general que contiene las ecuaciones diferenciales para el mecanismo y con su solucion se puede predecir con cierto grado de incertidumbre los gases a la salida de un ducto, los gases de salida llevaran particulas inquemadas y productos que pueden ser contaminantes o no, si hacemos variacion en las condiciones de trabajo podemos encontrar los valores optimos para trabajar con equipos que producen gases de escape, previendo con ello

  8. Direct numerical simulation of an isothermal reacting turbulent wall-jet

    Science.gov (United States)

    Pouransari, Zeinab; Brethouwer, Geert; Johansson, Arne V.

    2011-08-01

    In the present investigation, Direct Numerical Simulation (DNS) is used to study a binary irreversible and isothermal reaction in a plane turbulent wall-jet. The flow is compressible and a single-step global reaction between an oxidizer and a fuel species is solved. The inlet based Reynolds, Schmidt, and Mach numbers of the wall-jet are Re = 2000, Sc = 0.72, and M = 0.5, respectively, and a constant coflow velocity is applied above the jet. At the inlet, fuel and oxidizer enter the domain separately in a non-premixed manner. The turbulent structures of the velocity field show the common streaky patterns near the wall, while a somewhat patchy or spotty pattern is observed for the scalars and the reaction rate fluctuations in the near-wall region. The reaction mainly occurs in the upper shear layer in thin highly convoluted reaction zones, but it also takes place close to the wall. Analysis of turbulence and reaction statistics confirms the observations in the instantaneous snapshots, regarding the intermittent character of the reaction rate near the wall. A detailed study of the probability density functions of the reacting scalars and comparison to that of the passive scalar throughout the domain reveals the significance of the reaction influence as well as the wall effects on the scalar distributions. The higher order moments of both the velocities and the scalar concentrations are analyzed and show a satisfactory agreement with experiments. The simulations show that the reaction can both enhance and reduce the dissipation of fuel scalar, since there are two competing effects; on the one hand, the reaction causes sharper scalar gradients and thus a higher dissipation rate, on the other hand, the reaction consumes the fuel scalar thereby reducing the scalar dissipation.

  9. Reacting fluids analysis and polluting emissions; Analisis de fluidos reactivos y emisiones contaminantes

    Energy Technology Data Exchange (ETDEWEB)

    Munoz Ledo, Ramon; Ley Koo, Marcos [Instituto de Investigaciones Electricas, Cuernavaca (Mexico); Varela Ham, Ruben [Universidad Autonoma Metropolitana, Mexico, D. F. (Mexico)

    1992-12-31

    A problem is set up of a reacting flow which occurs in a gas exhausting duct, which is boiled down to a problem of initial conditions (temperature, pressure and concentration of species) freeing the selection of reaction mechanisms. Through some pre-established algorithms calculation routines can be programmed in specific problems of chemistry kinetics. With the calculation routines set forth in base of the selected mechanism, the temperature, pressure, etc., conditions, a general program is obtained containing the differential equations for the mechanisms, and with its solution, with a certain degree of uncertainty, the gases at a duct outlet can be predicted. The exhaust gases will carry unburned particles and products that can be polluting or not. If we vary the working conditions, we can find the optimum values to work with equipment that produces exhaust gases, anticipating with it the more efficient utilization of the equipment and the energy with the least possible pollution. [Espanol] Se plantea un problema de un flujo reactivo que se lleva a cabo en un ducto de salida de gases de escape, para lo cual se reduce a un problema de condiciones iniciales (temperatura, presion y concentracion de especies), y dejando en libertad la seleccion de mecanismos de reaccion. Mediante algunos algoritmos preestablecidos se pueden programar las rutinas de calculo en problemas especificos de cinetica quimica. Con las rutinas de calculo planteadas en base al mecanismo seleccionado, las condiciones de temperatura, presion, etc. se obtiene un programa general que contiene las ecuaciones diferenciales para el mecanismo y con su solucion se puede predecir con cierto grado de incertidumbre los gases a la salida de un ducto, los gases de salida llevaran particulas inquemadas y productos que pueden ser contaminantes o no, si hacemos variacion en las condiciones de trabajo podemos encontrar los valores optimos para trabajar con equipos que producen gases de escape, previendo con ello

  10. Structural determination of individual chemical species in a mixed system by iterative transformation factor analysis-based X-ray absorption spectroscopy combined with UV-visible absorption and quantum chemical calculation.

    Science.gov (United States)

    Ikeda, Atsushi; Hennig, Christoph; Rossberg, André; Tsushima, Satoru; Scheinost, Andreas C; Bernhard, Gert

    2008-02-15

    A multitechnique approach using extended X-ray absorption fine structure (EXAFS) spectroscopy based on iterative transformation factor analysis (ITFA), UV-visible absorption spectroscopy, and density functional theory (DFT) calculations has been performed in order to investigate the speciation of uranium(VI) nitrate species in acetonitrile and to identify the complex structure of individual species in the system. UV-visible spectral titration suggests that there are four different species in the system, that is, pure solvated species, mono-, di-, and trinitrate species. The pure EXAFS spectra of these individual species are extracted by ITFA from the measured spectral mixtures on the basis of the speciation distribution profile calculated from the UV-visible data. Data analysis of the extracted EXAFS spectra, with the help of DFT calculations, reveals the most probable complex structures of the individual species. The pure solvated species corresponds to a uranyl hydrate complex with an equatorial coordination number (CNeq) of 5, [UO2(H2O)5]2+. Nitrate ions tend to coordinate to the uranyl(VI) ion in a bidentate fashion rather than a unidentate one in acetonitrile for all the nitrate species. The mononitrate species forms the complex of [UO2(H2O)3NO3]+ with a CNeq value of 5, while the di- and trinitrate species have a CNeq value of 6, corresponding to [UO2(H2O)2(NO3)2]0 (D2h) and [UO2(NO3)3]- (D3h), respectively.

  11. Numerical Simulations of Two-Phase Reacting Flow in a Single-Element Lean Direct Injection (LDI) Combustor Using NCC

    Science.gov (United States)

    Liu, Nan-Suey; Shih, Tsan-Hsing; Wey, C. Thomas

    2011-01-01

    A series of numerical simulations of Jet-A spray reacting flow in a single-element lean direct injection (LDI) combustor have been conducted by using the National Combustion C