Science.gov

Sample records for multicomponent hydrocarbon mixtures

  1. Analysis of aromatic constituents in multicomponent hydrocarbon mixtures by infrared spectroscopy using multiple linear regression

    NASA Astrophysics Data System (ADS)

    Vesnin, V. L.; Muradov, V. G.

    2012-09-01

    Absorption spectra of multicomponent hydrocarbon mixtures based on n-heptane and isooctane with addition of benzene (up to 1%) and toluene and o-xylene (up to 20%) were investigated experimentally in the region of the first overtones of the hydrocarbon groups (λ = 1620-1780 nm). It was shown that their concentrations could be determined separately by using a multiple linear regression method. The optimum result was obtained by including four wavelengths at 1671, 1680, 1685, and 1695 nm, which took into account absorption of CH groups in benzene, toluene, and o-xylene and CH3 groups, respectively.

  2. Determination of low concentrations of aromatic hydrocarbons in multicomponent mixtures with iso-octane and n-heptane

    NASA Astrophysics Data System (ADS)

    Vesnin, V. L.; Muradov, V. G.

    2011-11-01

    We have experimentally studied the absorption spectra of hydrocarbon mixtures based on n-heptane and isooctane with small (1%-2%) additions of aromatic hydrocarbons (benzene, toluene, xylene). The study was conducted in the region of the first overtones of the vibrational spectra for the hydrocarbon groups CH3, CH2, CH. We show that four-component modeling of the absorption spectrum of the hydrocarbon mixture and minimization of the deviation of the model spectrum from the experimental spectrum allow us to separately determine the content of the aromatic additives for concentrations from 1%.

  3. Uphill diffusion in multicomponent mixtures.

    PubMed

    Krishna, Rajamani

    2015-05-21

    Molecular diffusion is an omnipresent phenomena that is important in a wide variety of contexts in chemical, physical, and biological processes. In the majority of cases, the diffusion process can be adequately described by Fick's law that postulates a linear relationship between the flux of any species and its own concentration gradient. Most commonly, a component diffuses down the concentration gradient. The major objective of this review is to highlight a very wide variety of situations that cause the uphill transport of one constituent in the mixture. Uphill diffusion may occur in multicomponent mixtures in which the diffusion flux of any species is strongly coupled to that of its partner species. Such coupling effects often arise from strong thermodynamic non-idealities. For a quantitative description we need to use chemical potential gradients as driving forces. The transport of ionic species in aqueous solutions is coupled with its partner ions because of the electro-neutrality constraints; such constraints may accelerate or decelerate a specific ion. When uphill diffusion occurs, we observe transient overshoots during equilibration; the equilibration process follows serpentine trajectories in composition space. For mixtures of liquids, alloys, ceramics and glasses the serpentine trajectories could cause entry into meta-stable composition zones; such entry could result in phenomena such as spinodal decomposition, spontaneous emulsification, and the Ouzo effect. For distillation of multicomponent mixtures that form azeotropes, uphill diffusion may allow crossing of distillation boundaries that are normally forbidden. For mixture separations with microporous adsorbents, uphill diffusion can cause supra-equilibrium loadings to be achieved during transient uptake within crystals; this allows the possibility of over-riding adsorption equilibrium for achieving difficult separations.

  4. Nucleate pool boiling of hydrocarbon mixtures

    SciTech Connect

    Sardesai, R.G.; Palen, J.W.; Thome, J.

    1986-01-01

    The Schlunder method can be correctly used to predict boiling heat transfer coefficient of multicomponent hydrocarbon mixtures. The method was tested against experimental mixtures containing up to five components. The Stephan-Abdelsalam correlation can be used to calculate a ''pseudo-single component'' boiling heat transfer coefficient for a mixture using weighted properties. The effective temperature driving force term and the high mass flux correction term in the Schlunder formulation are empirically adjusted to improve the accuracy of prediction. Predictions of the Schlunder method are sensitive to the VLE calculations. The UNIFAC method is used in this study for reasons discussed in the paper.

  5. Thermophysical Properties of Hydrocarbon Mixtures

    National Institute of Standards and Technology Data Gateway

    SRD 4 NIST Thermophysical Properties of Hydrocarbon Mixtures (PC database for purchase)   Interactive computer program for predicting thermodynamic and transport properties of pure fluids and fluid mixtures containing up to 20 components. The components are selected from a database of 196 components, mostly hydrocarbons.

  6. TMVOC-MP: a parallel numerical simulator for Three-PhaseNon-isothermal Flows of Multicomponent Hydrocarbon Mixtures inporous/fractured media

    SciTech Connect

    Zhang, Keni; Yamamoto, Hajime; Pruess, Karsten

    2008-02-15

    TMVOC-MP is a massively parallel version of the TMVOC code (Pruess and Battistelli, 2002), a numerical simulator for three-phase non-isothermal flow of water, gas, and a multicomponent mixture of volatile organic chemicals (VOCs) in multidimensional heterogeneous porous/fractured media. TMVOC-MP was developed by introducing massively parallel computing techniques into TMVOC. It retains the physical process model of TMVOC, designed for applications to contamination problems that involve hydrocarbon fuels or organic solvents in saturated and unsaturated zones. TMVOC-MP can model contaminant behavior under 'natural' environmental conditions, as well as for engineered systems, such as soil vapor extraction, groundwater pumping, or steam-assisted source remediation. With its sophisticated parallel computing techniques, TMVOC-MP can handle much larger problems than TMVOC, and can be much more computationally efficient. TMVOC-MP models multiphase fluid systems containing variable proportions of water, non-condensible gases (NCGs), and water-soluble volatile organic chemicals (VOCs). The user can specify the number and nature of NCGs and VOCs. There are no intrinsic limitations to the number of NCGs or VOCs, although the arrays for fluid components are currently dimensioned as 20, accommodating water plus 19 components that may be either NCGs or VOCs. Among them, NCG arrays are dimensioned as 10. The user may select NCGs from a data bank provided in the software. The currently available choices include O{sub 2}, N{sub 2}, CO{sub 2}, CH{sub 4}, ethane, ethylene, acetylene, and air (a pseudo-component treated with properties averaged from N{sub 2} and O{sub 2}). Thermophysical property data of VOCs can be selected from a chemical data bank, included with TMVOC-MP, that provides parameters for 26 commonly encountered chemicals. Users also can input their own data for other fluids. The fluid components may partition (volatilize and/or dissolve) among gas, aqueous, and NAPL

  7. TMVOC, A Numerical Simulator for Three-Phase Non-isothermal Flowsof Multicomponent Hydrocarbon Mixtures in Variably SaturatedHeterogeneous Media

    SciTech Connect

    Pruess, Karsten; Battistelli, Alfredo

    2005-08-20

    TMVOC is designed for studying subsurface contamination by volatile organic compounds (VOCs), such as hydrocarbon fuels and industrial solvents. It can model the one-, two-, or three-dimensional migration of non-aqueous phase liquids (NAPLs) through the unsaturated and saturated zones, the formation of an oil lens on the water table, the dissolution and subsequent transport of VOCs in groundwater, as well as the vaporization and migration of VOCs in the interstitial air of the unsaturated zone, and the reversible sorption of VOCs on the rock matrix of a porous medium. TMVOC accounts for differences in aqueous solubility and volatility of different VOCs that may be present in a NAPL. Thermal remediation treatments such as steam injection or electric resistance heating and associated phase change and flow effects can also be modeled. A simple half-life model for biodegradation is included as well.

  8. Foaming of mixtures of pure hydrocarbons

    NASA Technical Reports Server (NTRS)

    Robinson, J. V.; Woods, W. W.

    1950-01-01

    Mixtures of pure liquid hydrocarbons are capable of foaming. Nine hydrocarbons were mixed in pairs, in all possible combinations, and four proportions of each combination. These mixtures were sealed in glass tubes, and the foaming was tested by shaking. Mixtures of aliphatic with other aliphatic hydrocarbons, or of alkyl benzenes with other alkyl benzenes, did not foam. Mixtures of aliphatic hydrocarbons with alkyl benzenes did foam. The proportions of the mixtures greatly affected the foaming, the maximum foaming of 12 of 20 pairs being at the composition 20 percent aliphatic hydrocarbon, 80 percent alkyl benzene. Six seconds was the maximum foam lifetime of any of these mixtures. Aeroshell 120 lubricating oil was fractionated into 52 fractions and a residue by extraction with acetone in a fractionating extractor. The index of refraction, foam lifetime, color, and viscosity of these fractions were measured. Low viscosity and high index fractions were extracted first. The viscosity of the fractions extracted rose and the index decreased as fractionation proceeded. Foam lifetimes and color were lowest in the middle fractions. Significance is attached to the observation that none of the foam lifetimes of the fractions or residue is as high as the foam lifetime of the original Aeroshell, indicating that the foaming is not due to a particular foaming constituent, but rather to the entire mixture.

  9. Enrichment of light hydrocarbon mixture

    SciTech Connect

    Yang; Dali; Devlin, David; Barbero, Robert S.; Carrera, Martin E.; Colling, Craig W.

    2010-08-10

    Light hydrocarbon enrichment is accomplished using a vertically oriented distillation column having a plurality of vertically oriented, nonselective micro/mesoporous hollow fibers. Vapor having, for example, both propylene and propane is sent upward through the distillation column in between the hollow fibers. Vapor exits neat the top of the column and is condensed to form a liquid phase that is directed back downward through the lumen of the hollow fibers. As vapor continues to ascend and liquid continues to countercurrently descend, the liquid at the bottom of the column becomes enriched in a higher boiling point, light hydrocarbon (propane, for example) and the vapor at the top becomes enriched in a lower boiling point light hydrocarbon (propylene, for example). The hollow fiber becomes wetted with liquid during the process.

  10. Enrichment of light hydrocarbon mixture

    SciTech Connect

    Yang, Dali; Devlin, David; Barbero, Robert S; Carrera, Martin E; Colling, Craig W

    2011-11-29

    Light hydrocarbon enrichment is accomplished using a vertically oriented distillation column having a plurality of vertically oriented, nonselective micro/mesoporous hollow fibers. Vapor having, for example, both propylene and propane is sent upward through the distillation column in between the hollow fibers. Vapor exits neat the top of the column and is condensed to form a liquid phase that is directed back downward through the lumen of the hollow fibers. As vapor continues to ascend and liquid continues to countercurrently descend, the liquid at the bottom of the column becomes enriched in a higher boiling point, light hydrocarbon (propane, for example) and the vapor at the top becomes enriched in a lower boiling point light hydrocarbon (propylene, for example). The hollow fiber becomes wetted with liquid during the process.

  11. On the separation of multicomponent mixtures in a cylindrical thermogravitational column

    NASA Astrophysics Data System (ADS)

    Kozlova, Sofia V.; Ryzhkov, Ilya I.

    2016-11-01

    This work studies the stationary separation of a multicomponent mixture in a thermogravitational column (TGC). The existing theory for a flat-plate column is extended to the case of a cylindrical column. The equations of motion and heat/mass transfer are written in cylindrical coordinates to take into account the impact of the cylinders curvature and the ratio of their radii on the separation process. To characterize the impact of each component on convective motion induced by thermal diffusion, the dimensionless separation ratios are used. A multicomponent system as a whole is described by the net separation ratio. The approximation neglecting vertical diffusion in the column is employed and conditions for its validity are analyzed. The profiles of velocity, temperature, composition, and density in the column with a multicomponent mixture are found and their dependence on the separation ratios and the ratio of cylinders radii is analyzed. The vertical separation is described by the solutal Rayleigh numbers, which are proportional to the vertical concentration gradients. It is shown that the key relation of TGC theory, which relates the net solutal Rayleigh number to the net separation ratio, essentially depends on the ratio of cylinders radii. The working formulas for the thermal diffusion coefficients are derived and the importance of forgotten effect is discussed. It is found that the vertical separation in the column increases with decreasing the ratio of inner and outer cylinders radii. A detailed comparison of results with the case of a flat-plate column is performed. Example of a ternary hydrocarbon mixture is analyzed on the basis of obtained solution and numerical simulation.

  12. Isentropic Compression of Multicomponent Mixtures of Fuels and Inert Gases

    NASA Technical Reports Server (NTRS)

    Barragan, Michelle; Julien, Howard L.; Woods, Stephen S.; Wilson, D. Bruce; Saulsberry, Regor L.

    2000-01-01

    In selected aerospace applications of the fuels hydrazine and monomethythydrazine, there occur conditions which can result in the isentropic compression of a multicomponent mixture of fuel and inert gas. One such example is when a driver gas such as helium comes out of solution and mixes with the fuel vapor, which is being compressed. A second example is when product gas from an energetic device mixes with the fuel vapor which is being compressed. Thermodynamic analysis has shown that under isentropic compression, the fuels hydrazine and monomethylhydrazine must be treated as real fluids using appropriate equations of state. The appropriate equations of state are the Peng-Robinson equation of state for hydrazine and the Redlich-Kwong-Soave equation of state for monomethylhydrazine. The addition of an inert gas of variable quantity and input temperature and pressure to the fuel compounds the problem for safety design or analysis. This work provides the appropriate thermodynamic analysis of isentropic compression of the two examples cited. In addition to an entropy balance describing the change of state, an enthalpy balance is required. The presence of multicomponents in the system requires that appropriate mixing rules are identified and applied to the analysis. This analysis is not currently available.

  13. IDENTIFICATION AND EXPERIMENTAL DATABASE FOR BINARY AND MULTICOMPONENT MIXTURES WITH POTENTIAL FOR INCREASING OVERALL CYCLE EFFICIENCY

    SciTech Connect

    Stephen M Bajorek; J. Schnelle

    2002-05-01

    This report describes an experimental investigation designed to identify binary and multicomponent mixture systems that may be for increasing the overall efficiency of a coal fired unit by extracting heat from flue gases. While ammonia-water mixtures have shown promise for increasing cycle efficiencies in a Kalina cycle, the costs and associated range of thermal conditions involved in a heat recovery system may prohibit its use in a relatively low temperature heat recovery system. This investigation considered commercially available non-azeotropic binary mixtures with a boiling range applicable to a flue gas initially at 477.6 K (400 F) and developed an experimental database of boiling heat transfer coefficients for those mixtures. In addition to their potential as working fluids for increasing cycle efficiency, cost, ease of handling, toxicity, and environmental concerns were considered in selection of the mixture systems to be examined experimentally. Based on this review, water-glycol systems were identified as good candidates. However, previous investigations of mixture boiling have focused on aqueous hydrocarbon mixtures, where water is the heaviest component. There have been few studies of water-glycol systems, and those that do exist have investigated boiling on plain surfaces only. In water-glycol systems, water is the light component, which makes these systems unique compared to those that have been previously examined. This report examines several water-glycol systems, and documents a database of experimental heat transfer coefficients for these systems. In addition, this investigation also examines the effect of an enhanced surface on pool boiling in water-glycol mixtures, by comparing boiling on a smooth surface to boiling on a Turbo IIIB. The experimental apparatus, test sections, and the experimental procedures are described. The mixture systems tested included water-propylene glycol, water-ethylene glycol, and water-diethylene glycol. All

  14. 40 CFR 721.10676 - Aromatic hydrocarbon mixture (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Aromatic hydrocarbon mixture (generic... Specific Chemical Substances § 721.10676 Aromatic hydrocarbon mixture (generic). (a) Chemical substance and... hydrocarbon mixture (PMN P-12-551) is subject to reporting under this section for the significant new...

  15. Coupling Oxygen Consumption with Hydrocarbon Oxidation in Bacterial Multicomponent Monooxygenases.

    PubMed

    Wang, Weixue; Liang, Alexandria D; Lippard, Stephen J

    2015-09-15

    A fundamental goal in catalysis is the coupling of multiple reactions to yield a desired product. Enzymes have evolved elegant approaches to address this grand challenge. A salient example is the biological conversion of methane to methanol catalyzed by soluble methane monooxygenase (sMMO), a member of the bacterial multicomponent monooxygenase (BMM) superfamily. sMMO is a dynamic protein complex of three components: a hydroxylase, a reductase, and a regulatory protein. The active site, a carboxylate-rich non-heme diiron center, is buried inside the 251 kDa hydroxylase component. The enzyme processes four substrates: O2, protons, electrons, and methane. To couple O2 activation to methane oxidation, timely control of substrate access to the active site is critical. Recent studies of sMMO, as well as its homologues in the BMM superfamily, have begun to unravel the mechanism. The emerging and unifying picture reveals that each substrate gains access to the active site along a specific pathway through the hydroxylase. Electrons and protons are delivered via a three-amino-acid pore located adjacent to the diiron center; O2 migrates via a series of hydrophobic cavities; and hydrocarbon substrates reach the active site through a channel or linked set of cavities. The gating of these pathways mediates entry of each substrate to the diiron active site in a timed sequence and is coordinated by dynamic interactions with the other component proteins. The result is coupling of dioxygen consumption with hydrocarbon oxidation, avoiding unproductive oxidation of the reductant rather than the desired hydrocarbon. To initiate catalysis, the reductase delivers two electrons to the diiron(III) center by binding over the pore of the hydroxylase. The regulatory component then displaces the reductase, docking onto the same surface of the hydroxylase. Formation of the hydroxylase-regulatory component complex (i) induces conformational changes of pore residues that may bring protons to the

  16. Evaporation of Liquid Hydrocarbon Mixtures on Titan

    NASA Astrophysics Data System (ADS)

    Luspay-Kuti, Adrienn; Chevrier, V. F.; Rivera-Valentin, E. G.; Singh, S.; Roe, L. A.; Wagner, A.

    2013-10-01

    Besides Earth, Titan is the only other known planetary body with proven stable liquids on its surface. The hydrological cycle of these liquid hydrocarbon mixtures is critical in understanding Titan’s atmosphere and surface features. Evaporation of liquid surface bodies has been indirectly observed as shoreline changes from measurements by Cassini ISS and RADAR (Hayes et al. 2011, Icarus 211, 655-671; Turtle et al. 2011, Science 18, 1414-1417.), but the long seasons of Saturn strongly limit the time span of these observations and their validity over the course of an entire Titan year. Using a novel Titan simulation chamber, the evaporation rate of liquid methane and dissolved nitrogen mixture under Titan surface conditions was derived (Luspay-Kuti et al. 2012, GRL 39, L23203), which is especially applicable to low latitude transient liquids. Polar lakes, though, are expected to be composed of a variety of hydrocarbons, primarily a mixture of ethane and methane (e.g. Cordier et al. 2009, ApJL 707, L128-L131). Here we performed laboratory simulations of ethane-methane mixtures with varying mole fraction under conditions suitable for the polar regions of Titan. We will discuss results specifically addressing the evaporation behavior as the solution becomes increasingly ethane dominated, providing quantitative values for the evaporation rate at every step. These laboratory results are relevant to polar lakes, such as Ontario Lacus, and can shed light on their stability.

  17. Uphill diffusion and phase separation in partially miscible multicomponent mixtures

    NASA Astrophysics Data System (ADS)

    He, Ping; Raghavan, Ashwin; Ghoniem, Ahmed

    2015-11-01

    The partially miscible multicomponent mixtures, which are frequently encountered in green chemistry processes, often exhibit complicated behaviors, and are critical to the production rate, energy efficiency, and pollution controls. Recent studies have been mainly focused on phase behaviors. However, the coupled phase equilibrium and transport process, which may be the answer to phase separations observed in experiments, is not well researched. Here, we present a numerical and theoretical study on coupled mixing of heavy oil and supercritical water, and the results of our state-of-art modeling agree with experimental measurements. We find that due to the non-ideal diffusion driving force, (1) strong uphill diffusion of heavy oil fractions occurs, (2) a new heavy oil phase is separated starting from the plait point, and heavy fractions become highly concentrated, and (3) water diffusion initially overshoots in oil, and is expelled lately. Finally, we conclude our analysis applicable to different molecules and conditions. The authors thank Saudi Aramco for supporting this work (contract number 6600023444).

  18. Influence factors of multicomponent mixtures containing reactive chemicals and their joint effects.

    PubMed

    Tian, Dayong; Lin, Zhifen; Yu, Jianqiao; Yin, Daqiang

    2012-08-01

    Organic chemicals usually coexist as a mixture in the environment, and the mixture toxicity of organic chemicals has received increased attention. However, research regarding the joint effects of reactive chemicals is lacking. In this study, we examined two kinds of reactive chemicals, cyanogenic toxicants and aldehydes and determined their joint effects on Photobacterium phosphoreum. Three factors were found to influence the joint effects of multicomponent mixtures containing reactive chemicals, including the number of components, the dominating components and the toxic ratios. With an increased number of components, the synergistic or antagonistic effects (interactions) will weaken to the additive effects (non-interactions) if the added component cannot yield a much stronger joint effect with an existing component. Contrarily, the joint effect of the mixture may become stronger instead of weaker if the added components can yield a much stronger joint effect than the existing joint effect of the multicomponent mixture. The components that yield the strongest interactions in their binary mixture can be considered the dominating components. These components contribute more to the interactions of multicomponent mixtures than other components. Moreover, the toxic ratios also influence the joint effects of the mixtures. This study provides an insight into what are the main factors and how they influence the joint effects of multicomponent mixtures containing reactive chemicals, and thus, the findings are beneficial to the study of mixture toxicology.

  19. Mixture including hydrogen and hydrocarbon having pressure-temperature stability

    NASA Technical Reports Server (NTRS)

    Mao, Wendy L. (Inventor); Mao, Ho-Kwang (Inventor)

    2009-01-01

    The invention relates to a method of storing hydrogen that employs a mixture of hydrogen and a hydrocarbon that can both be used as fuel. In one embodiment, the method involves maintaining a mixture including hydrogen and a hydrocarbon in the solid state at ambient pressure and a temperature in excess of about 10 K.

  20. Method for producing hydrocarbon and alcohol mixtures. [Patent application

    DOEpatents

    Compere, A.L.; Googin, J.M.; Griffith, W.L.

    1980-12-01

    It is an object of this invention to provide an efficient process for extracting alcohols and ketones from an aqueous solution containing the same into hydrocarbon fuel mixtures, such as gasoline, diesel fuel and fuel oil. Another object of the invention is to provide a mixture consisting of hydrocarbon, alcohols or ketones, polyoxyalkylene polymer and water which can be directly added to fuels or further purified. The above stated objects are achieved in accordance with a preferred embodiment of the invention by contacting an aqueous fermentation liquor with a hydrocarbon or hydrocarbon mixture containing carbon compounds having 5 to 18 carbon atoms, which may include gasoline, diesel fuel or fuel oil. The hydrocarbon-aqueous alcohol solution is mixed in the presence or one or more of a group of polyoxyalkylene polymers described in detail hereinafter; the fermentation alcohol being extracted into the hydrocarbon fuel-polyoxyalkylene polymer mixture.

  1. One- and multi-component theories of mixtures

    SciTech Connect

    Ree, F.H.

    1993-07-01

    We describe one-component statistical mechanical theories and van der Waal`s effective one-component mixture model. We then show how to apply them to mixtures (containing CO{sub 2}) to extract reliable unlike-pair potential involving CO{sub 2} molecules as well as their dissociation products. A more fundamental approach will require the development of a perturbation or variational theory of mixtures based on a non-additive hard-sphere mixture reference system. Recent progresses made in this direction by means of an integral equation and computer simulations is described.

  2. SECONDARY ORGANIC AEROSOL FORMATION FROM MIXTURES OF BIOGENIC HYDROCARBONS

    EPA Science Inventory

    In this work the influence of hydrocarbon mixtures on the overall Secondary Organic Aerosol yield is investigated. Photochemical reaction experiments were conducted using mixtures of a-pinene, isoprene and propene in the presence of NOx. Results of the experiments show...

  3. Rayleigh-Benard instability in multicomponent mixtures with the Soret effect

    NASA Astrophysics Data System (ADS)

    Ryzhkov, Ilya

    2011-11-01

    Convection in multicomponent mixtures can show a variety of flow patterns due to several heat and mass transfer mechanisms: convection, heat conduction, main and cross diffusion, and the Soret effect. Convective stability of multicomponent fluids has not been widely investigated so far. The use of simplifying assumptions (e.g. the absence of cross-diffusion) may lead to the disagreement between theory and experiment. We study the stability of a plane multicomponent fluid layer heated from above/below in gravity field. In the basic state, the fluid is at rest and temperature gradient induces concentration gradients due to the Soret effect. The problem is reduced to that without cross-diffusion and Soret effect by a special transformation. Several types of boundary conditions are considered: 1) free, permeable 2) rigid, permeable 3) rigid, impermeable. The theorems, which generalize the exchange of stability principle to multicomponent fluids, are proved for boundary conditions 1 and 2. An explicit formula for critical Rayleigh numbers is obtained for boundary conditions 1. The stability problem for boundary conditions 3 was solved numerically for a ternary mixture. The stability maps are constructed in a wide range of parameters. The work is supported by the Interdisciplinary project of SB RAS N 116 and Krasnoyarsk Science Foundation.

  4. Use of neural networks for prediction of vapor/liquid equilibrium K values for light-hydrocarbon mixtures

    SciTech Connect

    Habiballah, W.A.; Startzman, R.A.; Barrufet, M.A.

    1996-05-01

    Equilibrium ratios play a fundamental role in the understanding of phase behavior of hydrocarbon mixtures. They are important in predicting compositional changes under varying temperature and pressure in reservoirs, surface separators, and production and transportation facilities. In particular, they are critical for reliable and successful compositional reservoir simulation. This paper presents a new approach for predicting K values with neural networks (NN`s). The method is applied to binary and multicomponent mixtures, and K-value prediction accuracy is on the order of the traditional methods. However, computing speed is significantly faster.

  5. Water uptake of multicomponent organic mixtures and their influence on hygroscopicity of inorganic salts.

    PubMed

    Wang, Yuanyuan; Jing, Bo; Guo, Yucong; Li, Junling; Tong, Shengrui; Zhang, Yunhong; Ge, Maofa

    2016-07-01

    The hygroscopic behaviors of atmospherically relevant multicomponent water soluble organic compounds (WSOCs) and their effects on ammonium sulfate (AS) and sodium chloride were investigated using a hygroscopicity tandem differential mobility analyzer (HTDMA) in the relative humidity (RH) range of 5%-90%. The measured hygroscopic growth was compared with predictions from the Extended-Aerosol Inorganics Model (E-AIM) and Zdanovskii-Stokes-Robinson (ZSR) method. The equal mass multicomponent WSOCs mixture containing levoglucosan, succinic acid, phthalic acid and humic acid showed gradual water uptake without obvious phase change over the whole RH range. It was found that the organic content played an important role in the water uptake of mixed particles. When organic content was dominant in the mixture (75%), the measured hygroscopic growth was higher than predictions from the E-AIM or ZSR relation, especially under high RH conditions. For mass fractions of organics not larger than 50%, the hygroscopic growth of mixtures was in good agreement with model predictions. The influence of interactions between inorganic and organic components on the hygroscopicity of mixed particles was related to the salt type and organic content. These results could contribute to understanding of the hygroscopic behaviors of multicomponent aerosol particles.

  6. Bonding and structure in dense multi-component molecular mixtures

    SciTech Connect

    Meyer, Edmund R.; Ticknor, Christopher; Bethkenhagen, Mandy; Hamel, Sebastien; Redmer, Ronald; Kress, Joel D.; Collins, Lee A.

    2015-10-30

    We have performed finite-temperature density functional theory molecular dynamics simulations on dense methane, ammonia, and water mixtures (CH4:NH3:H2O) for various compositions and temperatures (2000 K ≤ T ≤ 10000 K) that span a set of possible conditions in the interiors of ice-giant exoplanets. The equation-of-state, pair distribution functions, and bond autocorrelation functions (BACF) were used to probe the structure and dynamics of these complex fluids. In particular, an improvement to the choice of the cutoff in the BACF was developed that allowed analysis refinements for density and temperature effects. We note the relative changes in the nature of these systems engendered by variations in the concentration ratios. As a result, a basic tenet emerges from all these comparisons that varying the relative amounts of the three heavy components (C,N,O) can effect considerable changes in the nature of the fluid and may in turn have ramifications for the structure and composition of various planetary layers.

  7. Bonding and structure in dense multi-component molecular mixtures

    DOE PAGES

    Meyer, Edmund R.; Ticknor, Christopher; Bethkenhagen, Mandy; ...

    2015-10-30

    We have performed finite-temperature density functional theory molecular dynamics simulations on dense methane, ammonia, and water mixtures (CH4:NH3:H2O) for various compositions and temperatures (2000 K ≤ T ≤ 10000 K) that span a set of possible conditions in the interiors of ice-giant exoplanets. The equation-of-state, pair distribution functions, and bond autocorrelation functions (BACF) were used to probe the structure and dynamics of these complex fluids. In particular, an improvement to the choice of the cutoff in the BACF was developed that allowed analysis refinements for density and temperature effects. We note the relative changes in the nature of these systemsmore » engendered by variations in the concentration ratios. As a result, a basic tenet emerges from all these comparisons that varying the relative amounts of the three heavy components (C,N,O) can effect considerable changes in the nature of the fluid and may in turn have ramifications for the structure and composition of various planetary layers.« less

  8. Thermodynamics of Multicomponent PAH Mixtures and Development of Tar-Like Behavior

    PubMed Central

    Rice, James W.; Fu, Jinxia; Suuberg, Eric M.

    2011-01-01

    This study explores the solid/liquid phase behavior of mixtures of polycyclic aromatic hydrocarbons (PAHs), exploring the transition from non-ideal solid mixtures to a relatively ideal liquid behavior characteristic of “tars”. PAH mixtures have been studied using differential scanning calorimetry, melting point analysis and Knudsen effusion. Mixtures of anthracene, pyrene and fluoranthene show behavior that is consistent with other binary PAH mixtures; that is, the initially solid mixture exhibits a significant melting point depression, relative to the pure components, and in a certain range of composition, solid azeotrope behavior on vaporization. As the number of distinct PAH species is increased (by adding in benzo[a]pyrene, phenanthrene, fluorene and chrysene) this behavior gradually gives way to liquid phase character at even room temperature, and the vaporization behavior approaches that crudely predictable from ideal mixture theory. PMID:21442010

  9. Free Volume Theory of Hydrocarbon Mixture Transport in Nanoporous Materials.

    PubMed

    Obliger, Amaël; Pellenq, Roland; Ulm, Franz-Josef; Coasne, Benoit

    2016-10-06

    Despite recent focus on shale gas, hydrocarbon recovery from the ultraconfining and disordered porosity of organic matter in shales (kerogen) remains poorly understood. Key aspects such as the breakdown of hydrodynamics at the nanoscale and strong adsorption effects lead to unexplained non-Darcy behaviors. Here, molecular dynamics and statistical mechanics are used to elucidate hydrocarbon mixture transport through a realistic molecular model of kerogen [ Bousige, C.; et al. Nat. Mater. 2016 , 15 , 576 ]. Owing to strong adsorption effects, velocity cross-correlations between the mixture components and between molecules of the same species are shown to be negligible. This allows estimation of each component permeance from its self-diffusivity, which can be obtained from single-component data. These permeances are found to scale with the reciprocal of the alkane length and decrease with the number of adsorbed molecules following a simple free volume theory, therefore allowing mixture transport prediction as a function of the amount of trapped fluid.

  10. Multicomponent Diffusion of Penetrant Mixtures in Rubbery Polymers: A Molecular Dynamics Study

    NASA Astrophysics Data System (ADS)

    Bringuier, Stefan; Varady, Mark; Knox, Craig; Cabalo, Jerry; Pearl, Thomas; Mantooth, Brent

    The importance of understanding transport of chemical species across liquid-solid boundaries is of particular interest in the decontamination of harmful chemicals absorbed within polymeric materials. To characterize processes associated with liquid-phase extraction of absorbed species from polymers, it is necessary to determine an appropriate physical description of species transport in multicomponent systems. The Maxwell-Stefan (M-S) formulation is a rigorous description of mass transport in multicomponent solutions, in which, mutual diffusivities determine the degree of relative motion between interacting molecules in response to a chemical potential gradient. The work presented focuses on the determination of M-S diffusivities from molecular dynamics (MD) simulations of nerve agent O-ethyl S-[2(diisopropylamino)ethyl] methylphosphonothioate (VX), water, and methanol mixtures within a poly(dimethylsiloxane) matrix. We investigate the composition dependence of M-S diffusivities and compare the results to values predicted using empirical relations for binary and ternary mixtures. Finally, we highlight the pertinent differences in molecular mechanisms associated with species transport and employ non-equilibrium MD to probe transport across the mixture-polymer interface.

  11. Nanosecond-gated laser induced breakdown spectroscopy in hydrocarbon mixtures

    NASA Astrophysics Data System (ADS)

    Kobayashi, Kazunobu; Bak, Moon Soo; Tanaka, Hiroki; Do, Hyungrok

    2015-09-01

    Nanosecond-gated laser induced breakdown spectroscopy have been carried out in four different hydrocarbon gas mixtures (CH4/CO2/O2/N2, C2H4/O2/N2, C3H8/CO2/O2/N2 and C4H10/CO2/O2/N2) to investigate the effect of gas species on the laser induced breakdown kinetics and resulting the plasma emission. For this purpose, each mixture that consists of different species has the same atom composition. It is found that the temporal emission spectra and the decay rates of atomic line-intensities are almost identical for the breakdowns in the four different mixtures. This finding may indicate that the breakdown plasmas of these mixtures reach a similar thermodynamic and physiochemical state after its formation, resulting in a similar trend of quenching of excited species.

  12. Consensus sediment quality guidelines for polycyclic aromatic hydrocarbon mixtures

    SciTech Connect

    Swartz, R.C.

    1999-04-01

    Sediment quality guidelines (SQGs) for polycyclic aromatic hydrocarbons (PAHs) have been derived from a variety of laboratory, field, and theoretical foundations. They include the screening level concentration, effects ranges-low and -median, equilibrium partitioning concentrations, apparent effects threshold, {Sigma}PAH model, and threshold and probable effects levels. The resolution of controversial differences among the PAH SQGs lies in an understanding of the effects of mixtures. Polycyclic aromatic hydrocarbons virtually always occur in field-collected sediment as a complex mixture of covarying compounds. When expressed as a mixture concentration, that is, total PAH (TPAH), the guidelines form three clusters that were intended in their original derivations to represent threshold (TEC = 290 {micro}g/g organic carbon [OC]), median (MEC = 1,800 {micro}g/g OC), and extreme (EEC = 10,000 {micro}g/g OC) effects concentrations. The TEC/MEC/EEC consensus guidelines provide a unifying synthesis of other SQGs, reflect causal rather than correlative effects, account for mixtures, and predict sediment toxicity and benthic community perturbations at sites of PAH contamination. The TEC offers the most useful SQG because PAH mixtures are unlikely to cause adverse effects on benthic ecosystems below the TEC.

  13. Hygroscopic behavior of multicomponent organic aerosols and their internal mixtures with ammonium sulfate

    NASA Astrophysics Data System (ADS)

    Jing, B.; Tong, S. R.; Liu, Q. F.; Li, K.; Wang, W. G.; Zhang, Y. H.; Ge, M. F.

    2015-08-01

    Water soluble organic compounds (WSOCs) are important components of organics in the atmospheric fine particulate matter. Although WSOCs play an important role in the hygroscopicity of aerosols, water uptake behavior of internally mixed WSOC aerosols remains limited characterization. Here, the hygroscopic properties of single component such as levoglucosan, oxalic acid, malonic acid, succinic acid and phthalic acid and multicomponent WSOC aerosols mainly involving oxalic acid are investigated with the hygroscopicity tandem differential mobility analyzer (HTDMA). The coexisting hygroscopic species including levoglucosan, malonic acid and phthalic acid have strong influence on the hygroscopic growth and phase behavior of oxalic acid, even suppress its crystallization completely. The interactions between oxalic acid and levoglucosan are confirmed by infrared spectra. The discrepancies between measured growth factors and predictions from Extended Aerosol Inorganics Model (E-AIM) with UNIFAC method and Zdanovskii-Stokes-Robinson (ZSR) approach increase at medium and high relative humidity (RH) assuming oxalic acid in a solid state. For the internal mixture of oxalic acid with levoglucosan or succinic acid, there is enhanced water uptake at high RH due to positive chemical interactions between solutes. Organic mixture has more complex effect on the hygroscopicity of ammonium sulfate than single species. Although hygroscopic species such as levoglucosan accounts for a small fraction in the multicomponent aerosols, they may still strongly influence the hygroscopic behavior of ammonium sulfate by changing phase state of oxalic acid which plays the role of "intermediate" species. Considering the abundance of oxalic acid in the atmospheric aerosols, its mixtures with hygroscopic species may significantly promote water uptake under high RH conditions and thus affect the cloud condensation nuclei (CCN) activity, optical properties and chemical reactivity of atmospheric particles.

  14. Hygroscopic behavior of multicomponent organic aerosols and their internal mixtures with ammonium sulfate

    NASA Astrophysics Data System (ADS)

    Jing, Bo; Tong, Shengrui; Liu, Qifan; Li, Kun; Wang, Weigang; Zhang, Yunhong; Ge, Maofa

    2016-03-01

    Water-soluble organic compounds (WSOCs) are important components of organics in the atmospheric fine particulate matter. Although WSOCs play an important role in the hygroscopicity of aerosols, knowledge on the water uptake behavior of internally mixed WSOC aerosols remains limited. Here, the hygroscopic properties of single components such as levoglucosan, oxalic acid, malonic acid, succinic acid, phthalic acid, and multicomponent WSOC aerosols mainly involving oxalic acid are investigated with the hygroscopicity tandem differential mobility analyzer (HTDMA). The coexisting hygroscopic species including levoglucosan, malonic acid, and phthalic acid have a strong influence on the hygroscopic growth and phase behavior of oxalic acid, even suppressing its crystallization completely during the drying process. The phase behaviors of oxalic acid/levoglucosan mixed particles are confirmed by infrared spectra. The discrepancies between measured growth factors and predictions from Extended Aerosol Inorganics Model (E-AIM) with the Universal Quasi-Chemical Functional Group Activity Coefficient (UNIFAC) method and Zdanovskii-Stokes-Robinson (ZSR) approach increase at medium and high relative humidity (RH) assuming oxalic acid in a crystalline solid state. For the internal mixture of oxalic acid with levoglucosan or succinic acid, there is enhanced water uptake at high RH compared to the model predictions based on reasonable oxalic acid phase assumption. Organic mixture has more complex effects on the hygroscopicity of ammonium sulfate than single species. Although hygroscopic species such as levoglucosan account for a small fraction in the multicomponent aerosols, they may still strongly influence the hygroscopic behavior of ammonium sulfate by changing the phase state of oxalic acid which plays the role of "intermediate" species. Considering the abundance of oxalic acid in the atmospheric aerosols, its mixtures with hygroscopic species may significantly promote water uptake

  15. Sedimentation dynamics and equilibrium profiles in multicomponent mixtures of colloidal particles.

    PubMed

    Spruijt, E; Biesheuvel, P M

    2014-02-19

    In this paper we give a general theoretical framework that describes the sedimentation of multicomponent mixtures of particles with sizes ranging from molecules to macroscopic bodies. Both equilibrium sedimentation profiles and the dynamic process of settling, or its converse, creaming, are modeled. Equilibrium profiles are found to be in perfect agreement with experiments. Our model reconciles two apparently contradicting points of view about buoyancy, thereby resolving a long-lived paradox about the correct choice of the buoyant density. On the one hand, the buoyancy force follows necessarily from the suspension density, as it relates to the hydrostatic pressure gradient. On the other hand, sedimentation profiles of colloidal suspensions can be calculated directly using the fluid density as apparent buoyant density in colloidal systems in sedimentation-diffusion equilibrium (SDE) as a result of balancing gravitational and thermodynamic forces. Surprisingly, this balance also holds in multicomponent mixtures. This analysis resolves the ongoing debate of the correct choice of buoyant density (fluid or suspension): both approaches can be used in their own domain. We present calculations of equilibrium sedimentation profiles and dynamic sedimentation that show the consequences of these insights. In bidisperse mixtures of colloids, particles with a lower mass density than the homogeneous suspension will first cream and then settle, whereas particles with a suspension-matched mass density form transient, bimodal particle distributions during sedimentation, which disappear when equilibrium is reached. In all these cases, the centers of the distributions of the particles with the lowest mass density of the two, regardless of their actual mass, will be located in equilibrium above the so-called isopycnic point, a natural consequence of their hard-sphere interactions. We include these interactions using the Boublik-Mansoori-Carnahan-Starling-Leland (BMCSL) equation of

  16. Thermodiffusion of polycyclic aromatic hydrocarbons in binary mixtures

    NASA Astrophysics Data System (ADS)

    Hashmi, Sara M.; Senthilnathan, Sid; Firoozabadi, Abbas

    2016-11-01

    Thermodiffusion in liquid mixtures may explain some counter-intuitive but naturally occurring phenomena such as hydrocarbon reservoirs with heavier component(s) stratified on top of lighter ones. However, beyond benchmark systems, systematic measurements of thermodiffusion in binary organic mixtures are lacking. We use an optical beam deflection apparatus to simultaneously probe Fickian and thermal diffusion in binary solution mixtures of polycyclic aromatic hydrocarbons dissolved in alkanes, and measure both Fickian diffusion D and the Soret coefficient ST, and then obtain the thermodiffusion coefficient DT. In a series of nine binary mixtures, we vary both the size of the aromatic compound from two to four rings, as well as the length of the alkane chain from 6 to 16 carbons. To probe the effect of increasing ring size, we include a 6-ringed aromatic compound, coronene, and toluene as a solvent, due to the insolubility of coronene in alkanes. Our results suggest that Fickian diffusion increases with the inverse of solvent viscosity and also with decreasing molecular weight of the solute. While both of these trends match our intuition, the behavior of ST and DT is more complicated. We find that ST and DT increase with the solute molecular weight when the solvent is held fixed and that the impact of solute ring size is higher in shorter chain alkane solvents.

  17. Qualitative Analysis of Liquid Hydrocarbon Mixtures by Absorption Spectra of Their Vapors

    NASA Astrophysics Data System (ADS)

    Vesnin, V. L.

    2016-11-01

    Absorption spectra of saturated vapors of hydrocarbons and their mixtures were studied near their first overtones. Absorption spectra of hydrocarbons in the liquid and vapor states were compared. The ability to analyze qualitatively the compositions of liquid hydrocarbon mixtures using absorption spectra of their vapors was demonstrated. Indirect evidence suggested that the nonlinear absorption as a function of concentration that was seen in liquid hydrocarbon mixtures was negligible in their vapors.

  18. Emergence of life from multicomponent mixtures of chemicals: the case for experiments with cycling physicochemical gradients.

    PubMed

    Spitzer, Jan

    2013-04-01

    The emergence of life from planetary multicomponent mixtures of chemicals is arguably the most complicated and least understood natural phenomenon. The fact that living cells are non-equilibrium systems suggests that life can emerge only from non-equilibrium chemical systems. From an astrobiological standpoint, non-equilibrium chemical systems arise naturally when solar irradiation strikes rotating surfaces of habitable planets: the resulting cycling physicochemical gradients persistently drive planetary chemistries toward "embryonic" living systems and an eventual emergence of life. To better understand the factors that lead to the emergence of life, I argue for cycling non-equilibrium experiments with multicomponent chemical systems designed to represent the evolving chemistry of Hadean Earth ("prebiotic soups"). Specifically, I suggest experimentation with chemical engineering simulators of Hadean Earth to observe and analyze (i) the appearances and phase separations of surface active and polymeric materials as precursors of the first "cell envelopes" (membranes) and (ii) the accumulations, commingling, and co-reactivity of chemicals from atmospheric, oceanic, and terrestrial locations.

  19. Prebiotic hydrocarbon synthesis in impacting reduced astrophysical icy mixtures

    DOE PAGES

    Koziol, Lucas; Goldman, Nir

    2015-04-21

    We present results of prebiotic organic synthesis in shock-compressed reducing mixtures of simple ices from quantum molecular dynamics simulations extended to close to chemical equilibrium timescales. Given the relative abundance of carbon in reduced forms in astrophysical ices as well as the tendency of these mixtures to form complex hydrocarbons under the presence of external stimuli, it is possible that cometary impacts on a planetary surface could have yielded a larger array of prebiotic organic compounds than previously investigated. We find that the high pressures and temperatures due to shock compression yield a large assortment of carbon- and nitrogen-bonded extendedmore » structures that are highly reactive with short molecular lifetimes. Expansion and cooling causes these materials to break apart and form a wide variety of stable, potentially life-building compounds, including long-chain linear and branched hydrocarbons, large heterocyclic compounds, and a variety of different amines and exotic amino acids. Lastly, our results help provide a bottom-up understanding of hydrocarbon impact synthesis on the early Earth and its role in producing life-building molecules from simple starting materials.« less

  20. Prebiotic hydrocarbon synthesis in impacting reduced astrophysical icy mixtures

    SciTech Connect

    Koziol, Lucas; Goldman, Nir

    2015-04-21

    We present results of prebiotic organic synthesis in shock-compressed reducing mixtures of simple ices from quantum molecular dynamics simulations extended to close to chemical equilibrium timescales. Given the relative abundance of carbon in reduced forms in astrophysical ices as well as the tendency of these mixtures to form complex hydrocarbons under the presence of external stimuli, it is possible that cometary impacts on a planetary surface could have yielded a larger array of prebiotic organic compounds than previously investigated. We find that the high pressures and temperatures due to shock compression yield a large assortment of carbon- and nitrogen-bonded extended structures that are highly reactive with short molecular lifetimes. Expansion and cooling causes these materials to break apart and form a wide variety of stable, potentially life-building compounds, including long-chain linear and branched hydrocarbons, large heterocyclic compounds, and a variety of different amines and exotic amino acids. Lastly, our results help provide a bottom-up understanding of hydrocarbon impact synthesis on the early Earth and its role in producing life-building molecules from simple starting materials.

  1. PREBIOTIC HYDROCARBON SYNTHESIS IN IMPACTING REDUCED ASTROPHYSICAL ICY MIXTURES

    SciTech Connect

    Koziol, Lucas; Goldman, Nir E-mail: ngoldman@llnl.gov

    2015-04-20

    We present results of prebiotic organic synthesis in shock-compressed reducing mixtures of simple ices from quantum molecular dynamics simulations extended to close to chemical equilibrium timescales. Given the relative abundance of carbon in reduced forms in astrophysical ices as well as the tendency of these mixtures to form complex hydrocarbons under the presence of external stimuli, it is possible that cometary impacts on a planetary surface could have yielded a larger array of prebiotic organic compounds than previously investigated. We find that the high pressures and temperatures due to shock compression yield a large assortment of carbon- and nitrogen-bonded extended structures that are highly reactive with short molecular lifetimes. Expansion and cooling causes these materials to break apart and form a wide variety of stable, potentially life-building compounds, including long-chain linear and branched hydrocarbons, large heterocyclic compounds, and a variety of different amines and exotic amino acids. Our results help provide a bottom-up understanding of hydrocarbon impact synthesis on the early Earth and its role in producing life-building molecules from simple starting materials.

  2. Prebiotic Hydrocarbon Synthesis in Impacting Reduced Astrophysical Icy Mixtures

    NASA Astrophysics Data System (ADS)

    Koziol, Lucas; Goldman, Nir

    2015-04-01

    We present results of prebiotic organic synthesis in shock-compressed reducing mixtures of simple ices from quantum molecular dynamics simulations extended to close to chemical equilibrium timescales. Given the relative abundance of carbon in reduced forms in astrophysical ices as well as the tendency of these mixtures to form complex hydrocarbons under the presence of external stimuli, it is possible that cometary impacts on a planetary surface could have yielded a larger array of prebiotic organic compounds than previously investigated. We find that the high pressures and temperatures due to shock compression yield a large assortment of carbon- and nitrogen-bonded extended structures that are highly reactive with short molecular lifetimes. Expansion and cooling causes these materials to break apart and form a wide variety of stable, potentially life-building compounds, including long-chain linear and branched hydrocarbons, large heterocyclic compounds, and a variety of different amines and exotic amino acids. Our results help provide a bottom-up understanding of hydrocarbon impact synthesis on the early Earth and its role in producing life-building molecules from simple starting materials.

  3. Prebiotic hydrocarbon synthesis in impacting reduced astrophysical icy mixtures

    NASA Astrophysics Data System (ADS)

    Goldman, Nir; Koziol, Lucas

    2015-06-01

    We present results of prebiotic organic synthesis in shock compressed reducing mixtures of simple ices from quantum molecular dynamics simulations extended to close to chemical equilibrium time-scales. Given the relative abundance of carbon in reduced forms in astrophysical ices as well as the tendency of these mixtures to form complex hydrocarbons under the presence of external stimuli, it is possible that cometary impact on a planetary surface could have yielded a larger array of prebiotic organic compounds than previously investigated. We find that the high pressures and temperatures due to shock compression yield a large assortment of carbon and nitrogen bonded extended structures that are highly reactive with short molecular lifetimes. Expansion and cooling causes these materials to break apart and form a wide variety of stable, potentially life-building compounds, including long-chain linear and branched hydrocarbons, large heterocyclic compounds, and a variety of different amines and exotic amino acids. Our results help provide a bottom-up understanding for hydrocarbon impact synthesis on early Earth and its role in producing life building molecules from simple starting materials. This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

  4. Discrete velocity models for multicomponent mixtures and polyatomic molecules without nonphysical collision invariants and shock profiles

    NASA Astrophysics Data System (ADS)

    Bernhoff, Niclas

    2016-11-01

    An important aspect of constructing discrete velocity models (DVMs) for the Boltzmann equation is to obtain the right number of collision invariants. It is a well-known fact that, in difference to in the continuous case, DVMs can have extra collision invariants, so called spurious collision invariants, in plus to the physical ones. A DVM with only physical collision invariants, and so without spurious ones, is called normal. The construction of such normal DVMs has been studied a lot in the literature for single species as well as for binary mixtures. For binary mixtures also the concept of supernormal DVMs has been introduced by Bobylev and Vinerean. Supernormal DVMs are defined as normal DVMs such that both restrictions to the different species are normal as DVMs for single species. In this presentation we extend the concept of supernormal DVMs to the case of multicomponent mixtures and introduce it for polyatomic molecules. By polyatomic molecules we mean here that each molecule has one of a finite number of different internal energies, which can change, or not, during a collision. We will present some general algorithms for constructing such models, but also give some concrete examples of such constructions. The two different approaches above can be combined to obtain multicomponent mixtures with a finite number of different internal energies, and then be extended in a natural way to chemical reactions. The DVMs are constructed in such a way that we for the shock-wave problem obtain similar structures as for the classical discrete Boltzmann equation (DBE) for one species, and therefore will be able to apply previously obtained results for the DBE. In fact the DBE becomes a system of ordinary differential equations (dynamical system) and the shock profiles can be seen as heteroclinic orbits connecting two singular points (Maxwellians). The previous results for the DBE then give us the existence of shock profiles for shock speeds close to a typical speed

  5. Analysis of fire and explosion hazards of some hydrocarbon-air mixtures.

    PubMed

    Lizhong, Y; Weicheng, F; Xiaodong, Z; Qing'an, W

    2001-06-29

    Hazards caused by leakage of hydrocarbons have long been a problem. In this paper, the critical initiation energy and explosion limits of some hydrocarbon-air mixtures have been measured in confined (rectangle shock tube) and unconfined (plastic bag) condition tests. Two dimensionless parameters are suggested to compare the fire and explosion hazards of different hydrocarbons. Additionally, a series of experiments was performed to determine the influence of chemical additives on the fire and explosion hazards of some hydrocarbon-air mixtures in confined (rectangle shock tube) tests. These results relate directly to flammability and reactivity of hydrocarbon air mixtures. Such measurements are very important for hydrocarbon safety.

  6. Loss of thermodynamic work at the cascade stages during the separation of a multicomponent mixture of ideal gases

    NASA Astrophysics Data System (ADS)

    Chizhkov, V. P.; Boitsov, V. N.

    2016-01-01

    Formulas for estimating the thermodynamic work during the separation of components of binary and multicomponent mixtures are discussed and generalized. The difference between the work of separation determined from the separation potential and the thermodynamically estimated work during the isobaric-isothermal mixing of fractions separated at the ends of a cascade is calculated and explained.

  7. Mach 2 combustion characteristics of hydrogen/hydrocarbon fuel mixtures

    NASA Technical Reports Server (NTRS)

    Diskin, Glenn S.; Northam, G. Burton; Bell, Randy A.

    1987-01-01

    The combustion of H2/CH4 and H2/C2H4 mixtures containing 10-70 vol pct hydrocarbon at cumbustor inlet Mach number 2 and temperatures 2000-4000 R is investigated experimentally, applying direct-connect test hardware and techniques similar to those described by Diskin and Northam (1987) in the facilities of the NASA Langley Hypersonic Propulsion Branch. The experimental setup, procedures, and data-reduction methods are described; and the results are presented in extensive tables and graphs and characterized in detail. Fuel type and mixture are found to have little effect on the wall heating rate measured near the combustor exit, but H2/C2H4 is shown to burn much more efficiently than H2/CH4, with no pilot-off blowout at equivalence ratios greater than 0.5. It is suggested that H2/hydrocarbon mixtures are feasible fuels (at least in terms of combustion efficiency) for scramjet SSTO vehicles operating at freestream Mach numbers above 4.

  8. Mach 2 combustion characteristics of hydrogen/hydrocarbon fuel mixtures

    NASA Technical Reports Server (NTRS)

    Diskin, Glenn S.; Jachimowski, C. J.; Northam, G. Burton; Bell, Randy A.

    1987-01-01

    The combustion of H2/CH4 and H2/C2H4 mixtures containing 10 to 70 vol pct hydrocarbon at combustor inlet Mach number 2 and temperatures 2000 to 4000 R is investigated experimentally, applying direct-connect test hardware and techniques similar to those described by Diskin and Northam (1987) in the facilities of the NASA Langley Hypersonic Propulsion Branch. The experimental setup, procedures, and data-reduction methods are described; and the results are presented in extensive tables and graphs and characterized in detail. Fuel type and mixture are found to have little effect on the wall heating rate measured near the combustor exit, but H2/C2H4 is shown to burn much more efficiently than H2/CH4, with no pilot-off blowout equivalence ratios greater than 0.5. It is suggested that H2/hydrocarbon mixtures are feasible fuels (at least in terms of combustion efficiency) for scramjet SSTO vehicles operating at freestream Mach numbers above 4.

  9. The New TLC Method for Separation and Determination of Multicomponent Mixtures of Plant Extracts

    PubMed Central

    Matysik, Elżbieta; Woźniak, Anna; Paduch, Roman; Rejdak, Robert; Polak, Beata; Donica, Helena

    2016-01-01

    The new mode of two-dimensional gradient thin layer chromatography (MGD-2D TLC) has been presented. Short distance development of sample in the first dimension leads to formation of the preconcentrated narrow zones. They are consecutively separated in the second dimension with the mobile phase gradient in several steps of development until the eluent reaches the further end of the chromatographic plate. The use of the above-mentioned technique allows isolating and then identifying the compounds of various polarity from the multicomponent mixture. The practical application of two-dimensional gradient thin layer chromatography has been performed for isolation of the two plant (Juniperus and Thymus) oils components as the examples of test mixtures. The experiments have been carried out with the use of silica gel plates as well as a normal phase condition. The results of solute separation with isocratic one-dimensional thin layer chromatography system have been compared with those of two-dimensional gradient system. It has been observed that application of the latter mode leads to almost triplicated number of zones in comparison with the former one. It is purposeful to apply the proposed mode to control the purity of the dominant component or components of the mixture. PMID:26981317

  10. Efficient Discovery of Novel Multicomponent Mixtures for Hydrogen Storage: A Combined Computational/Experimental Approach

    SciTech Connect

    Wolverton, Christopher; Ozolins, Vidvuds; Kung, Harold H.; Yang, Jun; Hwang, Sonjong; Shore, Sheldon

    2016-11-28

    The objective of the proposed program is to discover novel mixed hydrides for hydrogen storage, which enable the DOE 2010 system-level goals. Our goal is to find a material that desorbs 8.5 wt.% H2 or more at temperatures below 85°C. The research program will combine first-principles calculations of reaction thermodynamics and kinetics with material and catalyst synthesis, testing, and characterization. We will combine materials from distinct categories (e.g., chemical and complex hydrides) to form novel multicomponent reactions. Systems to be studied include mixtures of complex hydrides and chemical hydrides [e.g. LiNH2+NH3BH3] and nitrogen-hydrogen based borohydrides [e.g. Al(BH4)3(NH3)3]. The 2010 and 2015 FreedomCAR/DOE targets for hydrogen storage systems are very challenging, and cannot be met with existing materials. The vast majority of the work to date has delineated materials into various classes, e.g., complex and metal hydrides, chemical hydrides, and sorbents. However, very recent studies indicate that mixtures of storage materials, particularly mixtures between various classes, hold promise to achieve technological attributes that materials within an individual class cannot reach. Our project involves a systematic, rational approach to designing novel multicomponent mixtures of materials with fast hydrogenation/dehydrogenation kinetics and favorable thermodynamics using a combination of state-of-the-art scientific computing and experimentation. We will use the accurate predictive power of first-principles modeling to understand the thermodynamic and microscopic kinetic processes involved in hydrogen release and uptake and to design new material/catalyst systems with improved properties. Detailed characterization and atomic-scale catalysis experiments will elucidate the effect of dopants and nanoscale catalysts in achieving fast kinetics and reversibility. And

  11. Spontaneous ignition delay characteristics of hydrocarbon fuel-air mixtures

    NASA Technical Reports Server (NTRS)

    Lefebvre, A. H.; Freeman, W. G.; Cowell, L. H.

    1986-01-01

    The influence of pressure on the autoignition characteristics of homogeneous mixtures of hydrocarbon fuels in air is examined. Autoignition delay times are measured for propane, ethylene, methane, and acetylene in a continuous flow apparatus featuring a multi-point fuel injector. Results are presented for mixture temperatures from 670K to 1020K, pressures from 1 to 10 atmospheres, equivalence ratios from 0.2 to 0.7, and velocities from 5 to 30 m/s. Delay time is related to pressure, temperature, and fuel concentration by global reaction theory. The results show variations in global activation energy from 25 to 38 kcal/kg-mol, pressure exponents from 0.66 to 1.21, and fuel concentration exponents from 0.19 to 0.75 for the fuels studied. These results are generally in good agreement with previous studies carried out under similar conditions.

  12. Calculation of thermodynamic functions for hydrocarbons and their mixtures

    NASA Astrophysics Data System (ADS)

    Perkins, Jeffery; Ho, Jason; Weinberg, Noham

    2013-06-01

    Knowledge of thermodynamic parameters of oil components in their pure forms and in mixtures is vital to understanding the properties of petroleum. The fact that hydrocarbons, thermodynamically unstable at ambient conditions, are formed spontaneously at geochemical conditions from a variety of precursors, ranging from kerogen to carbon, suggests that the thermodynamic stability of hydrocarbons increases dramatically with increasing pressure and temperature. Better grasp of their thermodynamic properties at extreme conditions is therefore crucially important both for our understanding of the processes of oil formation and for our ability to design and engineer new methods of synthetic oil production. Unfortunately, with a very few exceptions of the simplest compounds, such as e.g. methane, ethane, or ethene, these properties are tabulated for rather narrow ranges of pressures and temperatures, and in most cases are listed only for standard conditions at 25°C. We propose a new computational methodology, based on classical molecular dynamics simulations, for obtaining accurate thermodynamic functions, such as Gibbs energies, entropies, and enthalpies, of oil components and their mixtures at elevated and extreme temperatures and pressures.

  13. Unmixing Multi-Component Magnetic Mixtures in Geologic Materials Using First Order Reversal Curve Diagrams

    NASA Astrophysics Data System (ADS)

    Lascu, I.; Harrison, R. J.; Li, Y.; Muraszko, J.; Channell, J. E. T.; Piotrowski, A. M.; Hodell, D. A.; Necula, C.; Panaiotu, C. G.

    2015-12-01

    We have developed a magnetic unmixing method based on principal component analysis (PCA) of first-order reversal curve (FORC) diagrams. PCA provides an objective and robust statistical framework for unmixing, because it represents data variability as a linear combination of a limited number of principal components that are derived purely on the basis of natural variations contained within the dataset. For PCA we have resampled FORC distributions on grids that capture diagnostic signatures of magnetic domain states. Individual FORC diagrams were then recast as linear combinations of end-member (EM) FORC diagrams, located at user-defined positions in PCA space. The EM selection is guided by constraints derived from physical modeling, and is imposed by data scatter. To test our model, we have investigated temporal variations of two EMs in bulk North Atlantic sediment cores collected from the Rockall Trough and the Iberian Continental Margin. Sediments from these sites contain a mixture of magnetosomes and granulometrically distinct detrital magnetite. We have also quantified the spatial variation of three EM components in surficial sediments along the flow path of the North Atlantic Deep Water (NADW). These samples were separated into granulometric fractions, which also assisted in constraining EM definition. The unmixing model reveals systematic variations in EM relative abundance as a function of distance along NADW flow. Finally, we have applied PCA to the combined dataset of Rockall Trough and NADW sediments, which can be recast as a four-EM mixture, providing enhanced discrimination between components. Our method forms the foundation of a general solution to the problem of unmixing multi-component magnetic mixtures, a fundamental task of rock magnetic studies.

  14. Zwanzig model of multi-component mixtures of biaxial particles: y3 theory re-visited

    NASA Astrophysics Data System (ADS)

    Sokolova, E. P.; Tumanyan, N. P.; Vlasov, A. Yu.; Masters, A. J.

    The paper considers the thermodynamic and phase ordering properties of a multi-component Zwanzig mixture of hard rectangular biaxial parallelepipeds. An equation of state (EOS) is derived based on an estimate of the number of arrangements of the particles on a three- dimensional cubic lattice. The methodology is a generalization of the Flory-DiMarzio counting scheme, but, unlike previous work, this treatment is thermodynamically consistent. The results are independent of the order in which particles are placed on the lattice. By taking the limit of zero lattice spacing, a translationally continuous variant of the model (the off-lattice variant) is obtained. The EOS is identical to that obtained previously by a wide variety of different approaches. In the off-lattice limit, it corresponds to a third-level y-expansion and, in the case of a binary mixture of square platelets, it also corresponds to the EOS obtained from fundamental measure theory. On the lattice it is identical to the EOS obtained by retaining only complete stars in the virial expansion. The off-lattice theory is used to study binary mixtures of rods (R1 - R2) and binary mixtures of platelets (P1 - P2). The particles were uniaxial, of length (thickness) L and width D. The aspect ratios Γi = Li/Di of the components were kept constant (Γ1R = 15, Γ1P = 1/15 and Γ2R = 150, Γ2P = 1/150), so the second virial coefficient of R1 was identical to P1 and similarly for R2 and P2. The volume ratio of particles 1 and 2, v1/v2, was then varied, with the constraints that viR = viP and ILM0001. Results on nematic-isotropic (N - I) phase coexistence at an infinite dilution of component 2, are qualitatively similar for rods and platelets. At small values of the ratio v1/v2, the addition of component 2 (i.e. a thin rod (e.g. a polymer) or a thin plate) results in the stabilization of the nematic phase. For larger values of v1/v2, however, this effect is reversed and the addition of component 2 destabilizes the

  15. Study on the variation rules of the joint effects for multicomponent mixtures containing cyanogenic toxicants and aldehydes based on the transition state theory.

    PubMed

    Li, Weiying; Tian, Dayong; Lin, Zhifen; Wang, Dali; Yu, Hongxia

    2014-02-28

    Although the study of the variation rules of the joint effects for multicomponent mixtures has gained increasing attention, it still remains unclear how the variation occurs and what the relationships between the joint effects of multicomponent mixtures and their corresponding binary mixtures are. To explain how the variation occurs, this study first proposes a hypothesis on the variation rules of the joint effects using the well-known transition state theory. The hypothesis concluded that the joint effect of multicomponent mixtures is among the joint effects of the corresponding binary mixtures. This hypothesis was named the fishing hypothesis because there is a similarity between the action process of the joint effects and the fishing process. Next, the hypothesis was validated by use of the experimental data by evaluating the joint effects of binary, ternary and quaternary mixtures containing cyanogenic toxicants and aldehydes on Photobacterium phosphoreum. The application of the fishing hypothesis can explain the rule as to how the joint effects of a multicomponent-mixture vary with its number of components and their ratios. This study provides a good method to predict the joint effects of multicomponent mixtures using the joint effects of their corresponding binary mixtures. An improvement in the fishing hypothesis will be needed in our future studies due to the approximate assumptions used in the deduction of the hypothesis.

  16. 40 CFR Table 2c to Subpart E of... - Reactivity Factors for Aromatic Hydrocarbon Solvent Mixtures

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 5 2010-07-01 2010-07-01 false Reactivity Factors for Aromatic Hydrocarbon Solvent Mixtures 2C Table 2C to Subpart E of Part 59 Protection of Environment ENVIRONMENTAL... Hydrocarbon Solvent Mixtures Bin Boiling range (degrees F) Criteria Reactivityfactor 21 280-290...

  17. 40 CFR Table 2c to Subpart E of... - Reactivity Factors for Aromatic Hydrocarbon Solvent Mixtures

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 6 2014-07-01 2014-07-01 false Reactivity Factors for Aromatic Hydrocarbon Solvent Mixtures 2C Table 2C to Subpart E of Part 59 Protection of Environment ENVIRONMENTAL... Hydrocarbon Solvent Mixtures Bin Boiling range(degrees F) Criteria Reactivityfactor (g O3/g VOC) 21...

  18. 40 CFR Table 2c to Subpart E of... - Reactivity Factors for Aromatic Hydrocarbon Solvent Mixtures

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 5 2011-07-01 2011-07-01 false Reactivity Factors for Aromatic Hydrocarbon Solvent Mixtures 2C Table 2C to Subpart E of Part 59 Protection of Environment ENVIRONMENTAL... Hydrocarbon Solvent Mixtures Bin Boiling range (degrees F) Criteria Reactivityfactor 21 280-290...

  19. 40 CFR Table 2c to Subpart E of... - Reactivity Factors for Aromatic Hydrocarbon Solvent Mixtures

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 6 2013-07-01 2013-07-01 false Reactivity Factors for Aromatic Hydrocarbon Solvent Mixtures 2C Table 2C to Subpart E of Part 59 Protection of Environment ENVIRONMENTAL... Hydrocarbon Solvent Mixtures Bin Boiling range(degrees F) Criteria Reactivityfactor (g O3/g VOC) 21...

  20. 40 CFR Table 2c to Subpart E of... - Reactivity Factors for Aromatic Hydrocarbon Solvent Mixtures

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 6 2012-07-01 2012-07-01 false Reactivity Factors for Aromatic Hydrocarbon Solvent Mixtures 2C Table 2C to Subpart E of Part 59 Protection of Environment ENVIRONMENTAL... Hydrocarbon Solvent Mixtures Bin Boiling range(degrees F) Criteria Reactivityfactor (g O3/g VOC) 21...

  1. Bioremediation of Mixtures of High Molecular Weight Polycyclic Aromatic Hydrocarbons

    NASA Astrophysics Data System (ADS)

    Xu, H.; Wu, J.; Shi, X.; Sun, Y.

    2014-12-01

    Although bioremediation has been considered as one of the most promising means to remove polycyclic aromatic hydrocarbons (PAHs) from polluted environments, the efficacy of PAHs bioremediation still remains challenged, especially for high molecular weight PAHs (HMW PAHs) and their mixtures. This study was focused on (a) isolation and characterization of pure strain and mixed microbial communities able to degrade HMW PAHs and (b) further evaluation of the ability of the isolated microbes to degrade HMW PAHs mixtures in the absence and presence of indigenous flora. Fluoranthene, benzo[b]fluoranthene and pyrene were selected as the representative HMW PAHs in this study. A pure bacterial strain, identified as Herbaspirillum chlorophenolicum FA1, was isolated from activated sludge. A mixed bacterial community designated as consortium-4 was isolated from petroleum contaminated soils, containing Pseudomonas sp. FbP1、Enterobacter sp. FbP2、Hydrogenophaga sp. FbP3 and Luteolibacter pohnpeiensis. FbP4. To our knowledge, this is the first study to demonstrate that bacterial strains of Herbaspirillum chlorophenolicum FA1 and Luteolibacter pohnpeiensis. FbP4 can also degrade fluoranthene, benzo[b]fluoranthene and pyrene. Experiment results showed that both strain FA1 and consortium-4 could degrade fluoranthene, benzo[b]fluoranthene and pyrene within a wide range of temperature, pH and initial PAHs concentration. Degradation of HMW PAHs mixtures (binary and ternary) demonstrated the interactive effects that can alter the rate and extent of biodegradation within a mixture. The presence of indigenous flora was found to either increase or decrease the degradation of HMW PAHs, suggesting possible synergistic or competition effects. Biodegradation kinetics of HMW PAHs for sole substrates, binary and ternary systems was evaluated, with the purpose to better characterize and compare the biodegradation process of individual HMW PAH and mixtures of HMW PAHs. Results of this study

  2. Stable Isotope Labeling Strategy for Protein-Ligand Binding Analysis in Multi-Component Protein Mixtures

    NASA Astrophysics Data System (ADS)

    DeArmond, Patrick D.; West, Graham M.; Huang, Hai-Tsang; Fitzgerald, Michael C.

    2011-03-01

    Described here is a stable isotope labeling protocol that can be used with a chemical modification- and mass spectrometry-based protein-ligand binding assay for detecting and quantifying both the direct and indirect binding events that result from protein-ligand binding interactions. The protocol utilizes an H{2/16}O2 and H{2/18}O2 labeling strategy to evaluate the chemical denaturant dependence of methionine oxidation in proteins both in the presence and absence of a target ligand. The differential denaturant dependence to the oxidation reactions performed in the presence and absence of ligand provides a measure of the protein stability changes that occur as a result of direct interactions of proteins with the target ligand and/or as a result of indirect interactions involving other protein-ligand interactions that are either induced or disrupted by the ligand. The described protocol utilizes the 18O/16O ratio in the oxidized protein samples to quantify the ligand-induced protein stability changes. The ratio is determined using the isotopic distributions observed for the methionine-containing peptides used for protein identification in the LC-MS-based proteomics readout. The strategy is applied to a multi-component protein mixture in this proof-of-principle experiment, which was designed to evaluate the technique's ability to detect and quantify the direct binding interaction between cyclosporin A and cyclophilin A and to detect the indirect binding interaction between cyclosporin A and calcineurin (i.e., the protein-protein interaction between cyclophilin A and calcineurin that is induced by cyclosporin A binding to cyclophilin A).

  3. Enantiomer-specific analysis of multi-component mixtures by correlated electron imaging–ion mass spectrometry

    PubMed Central

    Fanood, Mohammad M Rafiee; Ram, N. Bhargava; Lehmann, C. Stefan; Powis, Ivan; Janssen, Maurice H. M.

    2015-01-01

    Simultaneous, enantiomer-specific identification of chiral molecules in multi-component mixtures is extremely challenging. Many established techniques for single-component analysis fail to provide selectivity in multi-component mixtures and lack sensitivity for dilute samples. Here we show how enantiomers may be differentiated by mass-selected photoelectron circular dichroism using an electron–ion coincidence imaging spectrometer. As proof of concept, vapours containing ∼1% of two chiral monoterpene molecules, limonene and camphor, are irradiated by a circularly polarized femtosecond laser, resulting in multiphoton near-threshold ionization with little molecular fragmentation. Large chiral asymmetries (2–4%) are observed in the mass-tagged photoelectron angular distributions. These asymmetries switch sign according to the handedness (R- or S-) of the enantiomer in the mixture and scale with enantiomeric excess of a component. The results demonstrate that mass spectrometric identification of mixtures of chiral molecules and quantitative determination of enantiomeric excess can be achieved in a table-top instrument. PMID:26104140

  4. Percolation segregation in multi-size and multi-component particulate mixtures: Measurement, sampling, and modeling

    NASA Astrophysics Data System (ADS)

    Jha, Anjani K.

    Particulate materials are routinely handled in large quantities by industries such as, agriculture, electronic, ceramic, chemical, cosmetic, fertilizer, food, nutraceutical, pharmaceutical, power, and powder metallurgy. These industries encounter segregation due to the difference in physical and mechanical properties of particulates. The general goal of this research was to study percolation segregation in multi-size and multi-component particulate mixtures, especially measurement, sampling, and modeling. A second generation primary segregation shear cell (PSSC-II), an industrial vibrator, a true cubical triaxial tester, and two samplers (triers) were used as primary test apparatuses for quantifying segregation and flowability; furthermore, to understand and propose strategies to mitigate segregation in particulates. Toward this end, percolation segregation in binary, ternary, and quaternary size mixtures for two particulate types: urea (spherical) and potash (angular) were studied. Three coarse size ranges 3,350-4,000 mum (mean size = 3,675 mum), 2,800-3,350 mum (3,075 mum), and 2,360-2,800 mum (2,580 mum) and three fines size ranges 2,000-2,360 mum (2,180 mum), 1,700-2,000 mum (1,850 mum), and 1,400-1,700 mum (1,550 mum) for angular-shaped and spherical-shaped were selected for tests. Since the fines size 1,550 mum of urea was not available in sufficient quantity; therefore, it was not included in tests. Percolation segregation in fertilizer bags was tested also at two vibration frequencies of 5 Hz and 7Hz. The segregation and flowability of binary mixtures of urea under three equilibrium relative humidities (40%, 50%, and 60%) were also tested. Furthermore, solid fertilizer sampling was performed to compare samples obtained from triers of opening widths 12.7 mm and 19.1 mm and to determine size segregation in blend fertilizers. Based on experimental results, the normalized segregation rate (NSR) of binary mixtures was dependent on size ratio, mixing ratio

  5. Method for removing chlorine compounds from hydrocarbon mixtures

    DOEpatents

    Janoski, Edward J.; Hollstein, Elmer J.

    1985-12-31

    A process for removing halide ions from a hydrocarbon feedstream containing halogenated hydrocarbons wherein the contaminated feedstock is contacted with a solution of a suitable oxidizing acid containing a lanthanide oxide, the acid being present in a concentration of at least about 50 weight percent for a time sufficient to remove substantially all of the halide ion from the hydrocarbon feedstock.

  6. Method for removing chlorine compounds from hydrocarbon mixtures

    DOEpatents

    Janoski, E.J.; Hollstein, E.J.

    1984-09-29

    A process for removing halide ions from a hydrocarbon feedstream containing halogenated hydrocarbons wherein the contaminated feedstock is contacted with a solution of a suitable oxidizing acid containing a lanthanide oxide, the acid being present in a concentration of at least about 50 weight percent for a time sufficient to remove substantially all of the halide ion from the hydrocarbon feedstock.

  7. Multicomponent adsorption of polycyclic aromatic hydrocarbons in Manufactured Gas Plant soils

    SciTech Connect

    Webb, O.F.; Phelps, T.J.; Bienkowski, P.R.

    1993-01-01

    Adsorption is an important process in the bioremediation of Manufactured Gas Plant (MGP) soils contaminated with high levels of polycyclic aromatic hydrocarbons (PAH). Over 2,000 sites nationwide exist that are contaminated with complex mixtures of PAH and other pollutants. Many PAH are classified as EPA priority pollutants. The adsorption properties of weathered contaminated soils are difficult to measure using pulse or step perturbations due to heterogeneous contaminant distributions and heterogeneous soil physical structure. This study compares the use of cyclical perturbations with step change perturbations to analyze these complex soil systems. The sinusoidal method proved to be more robust than the step perturbation method. Sinusoidal response was easier to interpret and was continuous. The step change method produced a transient response that was more difficult to interpret. Two parameters, period and amplitude, were available when using sinusoidal perturbation methods while only one parameter, magnitude of the step function, was available for dynamic studies using traditional step perturbation methods. Displacement behavior was observed with both sinusoidal and step experiments. Simulations are presented using favorable isotherms for an adsorption system using a sinusoidal feed input. Automated on-line high performance liquid chromatography and capillary gas chromatography systems developed for analysis are also described.

  8. Binary Mixtures of Polycyclic Aromatic Hydrocarbons Display Nonadditive Mixture Interactions in an In Vitro Liver Cell Model.

    PubMed

    Gaskill, Stacey J; Bruce, Erica D

    2016-05-01

    Polycyclic aromatic hydrocarbons (PAHs) have been labeled contaminants of concern due to their carcinogenic potential, insufficient toxicological data, environmental ubiquity, and inconsistencies in the composition of environmental mixtures. The Environmental Protection Agency is reevaluating current methods for assessing the toxicity of PAHs, including the assumption of toxic additivity in mixtures. This study was aimed at testing mixture interactions through in vitro cell culture experimentation, and modeling the toxicity using quantitative structure-activity relationships (QSAR). Clone-9 rat liver cells were used to analyze cellular proliferation, viability, and genotoxicity of 15 PAHs in single doses and binary mixtures. Tests revealed that many mixtures have nonadditive toxicity, but display varying mixture effects depending on the mixture composition. Many mixtures displayed antagonism, similar to other published studies. QSARs were then developed using the genetic function approximation algorithm to predict toxic activity both in single PAH congeners and in binary mixtures. Effective concentrations inhibiting 50% of the cell populations were modeled, with R(2) = 0.90, 0.99, and 0.84, respectively. The QSAR mixture algorithms were then adjusted to account for the observed mixture interactions as well as the mixture composition (ratios) to assess the feasibility of QSARs for mixtures. Based on these results, toxic addition is improbable and therefore environmental PAH mixtures are likely to see nonadditive responses when complex interactions occur between components. Furthermore, QSAR may be a useful tool to help bridge these data gaps surrounding the assessment of human health risks that are associated with PAH exposures.

  9. MULTISUBSTRATE BIODEGRADATION KINETICS FOR BINARY AND COMPLEX MIXTURES OF POLYCYCLIC AROMATIC HYDROCARBONS

    EPA Science Inventory

    Biodegradation kinetics were studied for binary and complex mixtures of nine polycyclic aromatic hydrocarbons (PAHs): naphthalene, 1-methylnaphthalene, 2-methylnaphthalene, 2-ethylnaphthalene, phenanthrene, anthracene, pyrene, fluorene and fluoranthene. Discrepancies between the ...

  10. 40 CFR Table 2b to Subpart E of... - Reactivity Factors for Aliphatic Hydrocarbon Solvent Mixtures

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Alkanes (2 to 460-580 Alkanes (8 to 22% Aromatics) 1.49 * Average Boiling Point = (Initial Boiling Point + Dry Point) / 2 (b) Aromatic Hydrocarbon Solvents ... Hydrocarbon Solvent Mixtures Bin Averageboiling point * (degrees F) Criteria Reactivityfactor 1 80-205...

  11. 40 CFR Table 2b to Subpart E of... - Reactivity Factors for Aliphatic Hydrocarbon Solvent Mixtures

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...-580 Alkanes (2 to 460-580 Alkanes (8 to 22% Aromatics) 1.49 * Average Boiling Point = (Initial Boiling Point + Dry Point)/2(b) Aromatic Hydrocarbon Solvents ... Hydrocarbon Solvent Mixtures Bin Averageboiling point* (degrees F) Criteria Reactivityfactor (g O3/g VOC) 1...

  12. 40 CFR Table 2b to Subpart E of... - Reactivity Factors for Aliphatic Hydrocarbon Solvent Mixtures

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...-580 Alkanes (2 to 460-580 Alkanes (8 to 22% Aromatics) 1.49 * Average Boiling Point = (Initial Boiling Point + Dry Point)/2(b) Aromatic Hydrocarbon Solvents ... Hydrocarbon Solvent Mixtures Bin Averageboiling point* (degrees F) Criteria Reactivityfactor (g O3/g VOC) 1...

  13. 40 CFR Table 2b to Subpart E of... - Reactivity Factors for Aliphatic Hydrocarbon Solvent Mixtures

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...-580 Alkanes (2 to 460-580 Alkanes (8 to 22% Aromatics) 1.49 * Average Boiling Point = (Initial Boiling Point + Dry Point)/2(b) Aromatic Hydrocarbon Solvents ... Hydrocarbon Solvent Mixtures Bin Averageboiling point* (degrees F) Criteria Reactivityfactor (g O3/g VOC) 1...

  14. 40 CFR Table 2b to Subpart E of... - Reactivity Factors for Aliphatic Hydrocarbon Solvent Mixtures

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Alkanes (2 to 460-580 Alkanes (8 to 22% Aromatics) 1.49 * Average Boiling Point = (Initial Boiling Point + Dry Point) / 2 (b) Aromatic Hydrocarbon Solvents ... Hydrocarbon Solvent Mixtures Bin Averageboiling point * (degrees F) Criteria Reactivityfactor 1 80-205...

  15. FLAME SUPPRESSION AND LUBRICANT INTERACTION OF HYDROCARBON MIXTURES FOR HOUSEHOLD REFRIGERATOR/FREEZERS

    EPA Science Inventory

    The paper discusses the flame suppression and lubricant interaction of hydrocarbon (HC) mixtures for household refrigerator/freezers (R/Fs). The work focuses on blending the minimum amount of a fluoroiodocarbon (FIC) with previously optimized R/F-tested HC mixtures to reduce thei...

  16. Dielectric constant of liquid alkanes and hydrocarbon mixtures

    NASA Technical Reports Server (NTRS)

    Sen, A. D.; Anicich, V. G.; Arakelian, T.

    1992-01-01

    The complex dielectric constants of n-alkanes with two to seven carbon atoms have been measured. The measurements were conducted using a slotted-line technique at 1.2 GHz and at atmospheric pressure. The temperature was varied from the melting point to the boiling point of the respective alkanes. The real part of the dielectric constant was found to decrease with increasing temperature and correlate with the change in the molar volume. An upper limit to all the loss tangents was established at 0.001. The complex dielectric constants of a few mixtures of liquid alkanes were also measured at room temperature. For a pentane-octane mixture the real part of the dielectric constant could be explained by the Clausius-Mosotti theory. For the mixtures of n-hexane-ethylacetate and n-hexane-acetone the real part of the dielectric constants could be explained by the Onsager theory extended to mixtures. The dielectric constant of the n-hexane-acetone mixture displayed deviations from the Onsager theory at the highest fractions of acetone. The dipole moments of ethylacetate and acetone were determined for dilute mixtures using the Onsager theory and were found to be in agreement with their accepted gas-phase values. The loss tangents of the mixtures exhibited a linear relationship with the volume fraction for low concentrations of the polar liquids.

  17. Dielectric constant of liquid alkanes and hydrocarbon mixtures.

    PubMed

    Sen, A D; Anicich, V G; Arakelian, T

    1992-01-01

    The complex dielectric constants of n-alkanes with two to seven carbon atoms have been measured. The measurements were conducted using a slotted-line technique at 1.2 GHz and at atmospheric pressure. The temperature was varied from the melting point to the boiling point of the respective alkanes. The real part of the dielectric constant was found to decrease with increasing temperature and correlate with the change in the molar volume. An upper limit to all the loss tangents was established at 0.001. The complex dielectric constants of a few mixtures of liquid alkanes were also measured at room temperature. For a pentane-octane mixture the real part of the dielectric constant could be explained by the Clausius-Mosotti theory. For the mixtures of n-hexane-ethylacetate and n-hexane-acetone the real part of the dielectric constants could be explained by the Onsager theory extended to mixtures. The dielectric constant of the n-hexane-acetone mixture displayed deviations from the Onsager theory at the highest fractions of acetone. The dipole moments of ethylacetate and acetone were determined for dilute mixtures using the Onsager theory and were found to be in agreement with their accepted gas-phase values. The loss tangents of the mixtures exhibited a linear relationship with the volume fraction for low concentrations of the polar liquids.

  18. Multicomponent membranes

    DOEpatents

    Kulprathipanja, Santi; Kulkarni, Sudhir S.; Funk, Edward W.

    1988-01-01

    A multicomponent membrane which may be used for separating various components which are present in a fluid feed mixture comprises a mixture of a plasticizer such as a glycol and an organic polymer cast upon a porous organic polymer support. The membrane may be prepared by casting an emulsion or a solution of the plasticizer and polymer on the porous support, evaporating the solvent and recovering the membrane after curing.

  19. Multicomponent effective medium-correlated random walk theory for the diffusion of fluid mixtures through porous media.

    PubMed

    Bonilla, Mauricio R; Bhatia, Suresh K

    2012-01-10

    Molecular transport in nanoconfined spaces plays a key role in many emerging technologies for gas separation and storage, as well as in nanofluidics. The infiltration of fluid mixtures into the voids of porous frameworks having complex topologies is common place to these technologies, and optimizing their performance entails developing a deeper understanding of how the flow of these mixtures is affected by the morphology of the pore space, particularly its pore size distribution and pore connectivity. Although several techniques have been developed for the estimation of the effective diffusivity characterizing the transport of single fluids through porous materials, this is not the case for fluid mixtures, where the only alternatives rely on a time-consuming solution of the pore network equations or adaptations of the single fluid theories which are useful for a limited type of systems. In this paper, a hybrid multicomponent effective medium-correlated random walk theory for the calculation of the effective transport coefficients matrix of fluid mixtures diffusing through porous materials is developed. The theory is suitable for those systems in which component fluxes at the single pore level can be related to the potential gradients of the different species through linear flux laws and corresponds to a generalization of the classical single fluid effective medium theory for the analysis of random resistor networks. Comparison with simulation of the diffusion of binary CO(2)/H(2)S and ternary CO(2)/H(2)S/C(3)H(8) gas mixtures in membranes modeled as large networks of randomly oriented pores with both continuous and discrete pore size distributions demonstrates the power of the theory, which was tested using the well-known generalized Maxwell-Stefan model for surface diffusion at the single pore level.

  20. Multiple Responses of Gram-Positive and Gram-Negative Bacteria to Mixture of Hydrocarbons

    PubMed Central

    Marilena Lăzăroaie, Mihaela

    2010-01-01

    Most of our knowledge about pollutants and the way they are biodegraded in the environment has previously been shaped by laboratory studies using hydrocarbon-degrading bacterial strains isolated from polluted sites. In present study Gram-positive (Mycobacterium sp. IBBPo1, Oerskovia sp. IBBPo2, Corynebacterium sp. IBBPo3) and Gram-negative (Chryseomonas sp. IBBPo7, Pseudomonas sp. IBBPo10, Burkholderia sp. IBBPo12) bacteria, isolated from oily sludge, were found to be able to tolerate pure and mixture of saturated hydrocarbons, as well as pure and mixture of monoaromatic and polyaromatic hydrocarbons. Isolated Gram-negative bacteria were more tolerant to mixture of saturated (n-hexane, n-hexadecane, cyclohexane), monoaromatic (benzene, toluene, ethylbenzene) and polyaromatic (naphthalene, 2-methylnaphthalene, fluorene) hydrocarbons than Gram-positive bacteria. There were observed cellular and molecular modifications induced by mixture of saturated, monoaromatic and polyaromatic hydrocarbons to Gram-positive and Gram-negative bacteria. These modifications differ from one strain to another and even for the same bacterial strain, according to the nature of hydrophobic substrate. PMID:24031541

  1. Perturbation theory for multicomponent fluids based on structural properties of hard-sphere chain mixtures

    SciTech Connect

    Hlushak, Stepan

    2015-09-28

    An analytical expression for the Laplace transform of the radial distribution function of a mixture of hard-sphere chains of arbitrary segment size and chain length is used to rigorously formulate the first-order Barker-Henderson perturbation theory for the contribution of the segment-segment dispersive interactions into thermodynamics of the Lennard-Jones chain mixtures. Based on this approximation, a simple variant of the statistical associating fluid theory is proposed and used to predict properties of several mixtures of chains of different lengths and segment sizes. The theory treats the dispersive interactions more rigorously than the conventional theories and provides means for more accurate description of dispersive interactions in the mixtures of highly asymmetric components.

  2. THE GENOTOXICITY OF PRIORITY POLYCYCLIC AROMATIC HYDROCARBONS IN COMPLEX MIXTURES

    EPA Science Inventory

    Risk assessment of complex environmental samples suffers from difficulty in identifying toxic components, inadequacy of available toxicity data, and a paucity of knowledge about the behavior of geno(toxic) substances in complex mixtures. Lack of information about the behavior of ...

  3. The Godunov Method for Calculating Multidimensional Flows of a One-Velocity Multicomponent Mixture

    NASA Astrophysics Data System (ADS)

    Surov, V. S.

    2016-09-01

    Computational formulas of the Godunov method are given for the equations of a generalized-equilibrium model of a heterogeneous medium on a curvilinear grid; with the use of this method, the problems of interaction of air shock waves with bubbles of various gases are investigated. Flow of a gas-liquid mixture in a nozzle mouthpiece is considered. The Prandtl-Meyer flow of a water-air mixture is calculated and compared with a self-similar solution.

  4. Oxygen sensor for monitoring gas mixtures containing hydrocarbons

    DOEpatents

    Ruka, R.J.; Basel, R.A.

    1996-03-12

    A gas sensor measures O{sub 2} content of a reformable monitored gas containing hydrocarbons, H{sub 2}O and/or CO{sub 2}, preferably in association with an electrochemical power generation system. The gas sensor has a housing communicating with the monitored gas environment and carries the monitored gas through an integral catalytic hydrocarbon reforming chamber containing a reforming catalyst, and over a solid electrolyte electrochemical cell used for sensing purposes. The electrochemical cell includes a solid electrolyte between a sensor electrode that is exposed to the monitored gas, and a reference electrode that is isolated in the housing from the monitored gas and is exposed to a reference gas environment. A heating element is also provided in heat transfer communication with the gas sensor. A circuit that can include controls operable to adjust operations via valves or the like is connected between the sensor electrode and the reference electrode to process the electrical signal developed by the electrochemical cell. The electrical signal varies as a measure of the equilibrium oxygen partial pressure of the monitored gas. Signal noise is effectively reduced by maintaining a constant temperature in the area of the electrochemical cell and providing a monitored gas at chemical equilibria when contacting the electrochemical cell. The output gas from the electrochemical cell of the sensor is fed back into the conduits of the power generating system. 4 figs.

  5. Oxygen sensor for monitoring gas mixtures containing hydrocarbons

    DOEpatents

    Ruka, Roswell J.; Basel, Richard A.

    1996-01-01

    A gas sensor measures O.sub.2 content of a reformable monitored gas containing hydrocarbons H.sub.2 O and/or CO.sub.2, preferably in association with an electrochemical power generation system. The gas sensor has a housing communicating with the monitored gas environment and carries the monitored gas through an integral catalytic hydrocarbon reforming chamber containing a reforming catalyst, and over a solid electrolyte electrochemical cell used for sensing purposes. The electrochemical cell includes a solid electrolyte between a sensor electrode that is exposed to the monitored gas, and a reference electrode that is isolated in the housing from the monitored gas and is exposed to a reference gas environment. A heating element is also provided in heat transfer communication with the gas sensor. A circuit that can include controls operable to adjust operations via valves or the like is connected between the sensor electrode and the reference electrode to process the electrical signal developed by the electrochemical cell. The electrical signal varies as a measure of the equilibrium oxygen partial pressure of the monitored gas. Signal noise is effectively reduced by maintaining a constant temperature in the area of the electrochemical cell and providing a monitored gas at chemical equilibria when contacting the electrochemical cell. The output gas from the electrochemical cell of the sensor is fed back into the conduits of the power generating system.

  6. Explosion pressures of hydrocarbon-air mixtures in closed vessels.

    PubMed

    Razus, Domnina; Movileanu, Codina; Brinzea, Venera; Oancea, D

    2006-07-31

    An experimental study on pressure evolution during closed vessel explosions of several gaseous fuel-air mixtures was performed, at various initial pressures within 0.3-1.2 bar and ambient initial temperature. Explosion pressures and explosion times are reported for methane-, n-pentane-, n-hexane-, propene-, butene-, butadiene-, cyclohexane- and benzene-air mixtures. The explosion pressures measured in a spherical vessel (Phi=10 cm) and in three cylindrical vessels with different diameter/height ratios are examined in comparison with the adiabatic explosion pressures, computed by assuming chemical equilibrium within the flame front. The influence of initial pressure, fuel concentration and heat losses during propagation (determined by the size and shape of the explosion vessel and by the position of the ignition source) on explosion pressures and explosion times are discussed for some of the examined systems.

  7. Evaporation of multi-component mixtures and shell formation in spray dried droplets

    NASA Astrophysics Data System (ADS)

    Valente, Pedro; Duarte, Íris; Porfirio, Tiago; Temtem, Márcio

    2015-11-01

    Drug particles where the active pharmaceutical ingredient (APIs) is dispersed in a polymer matrix forming an amorphous solid dispersion (ASD) is a commonly used strategy to increase the solubility and dissolution rate of poorly water soluble APIs. However, the formation and stability of an amorphous solid dispersion depends on the polymer/API combination and process conditions to generate it. The focus of the present work is to further develop a numerical tool to predict the formation of ASDs by spray drying solutions of different polymer/API combinations. Specifically, the evaporation of a multi-component droplet is coupled with a diffusion law within the droplet that minimizes the Gibbs free energy of the polymer/API/solvents system, following the Flory-Huggins model. Prior to the shell formation, the evaporation of the solvents is modelled following the simplified approach proposed by Abramzon & Sirignano (1989) which accounts for the varying relative velocity between the droplet and the drying gas. After shell formation, the diffusion of the solvents across the porous shell starkly modifies the evaporative dynamics.

  8. Laser-induced breakdown emission in hydrocarbon fuel mixtures

    NASA Astrophysics Data System (ADS)

    Kobayashi, Kazunobu; Bak, Moon Soo; Tanaka, Hiroki; Carter, Campbell; Do, Hyungrok

    2016-04-01

    Time-resolved emission measurements of laser-induced breakdown plasmas have been carried out to investigate the effect that gas species might have on the kinetics, particularly in excited states, and the resulting plasma properties. For this purpose, fuel-oxygen (O2)-carbon dioxide (CO2) mixtures with either helium (He) or nitrogen (N2) balance are prepared while maintaining their atomic compositions. The fuels tested in this study are methane (CH4), ethylene (C2H4), propane (C3H8), and butane (C4H10). The breakdown is produced in the mixtures (CH4/CO2/O2/He, C2H4/O2/He, C3H8/CO2/O2/He and C4H10/CO2/O2/He or CH4/CO2/O2/N2, C2H4/O2/N2, C3H8/CO2/O2/N2 and C4H10/CO2/O2/N2) at room conditions using the second harmonic of a Q-switched Nd:YAG laser (with pulse duration of 10 ns). The temporal evolution of plasma temperature is deduced from the ratio of two oxygen lines (777 nm and 823 nm) through Boltzmann analysis, while the evolution of electron number density is estimated based on Stark broadening of the Balmer-alpha (H α ) line at 656 nm and the measured plasma temperature. From the results, the temporal evolution of emission spectra and decay rates of atomic line-intensities are found to be almost identical between the breakdown plasma in the different mixtures given balancing gases. Furthermore, the temporal evolution of plasma temperature and electron number density are also found to be independent of the species compositions. Therefore, this behavior—of the breakdown emissions and plasma properties in the different mixtures with identical atomic composition—may be because the breakdown gases reach similar thermodynamic and physiochemical states immediately after the breakdown.

  9. Molecular-thermodynamic theory of micellization of multicomponent surfactant mixtures: 2. pH-sensitive surfactants.

    PubMed

    Goldsipe, Arthur; Blankschtein, Daniel

    2007-05-22

    In article 1 of this series, we developed a molecular-thermodynamic (MT) theory to model the micellization of mixtures containing an arbitrary number of conventional (pH-insensitive) surfactants. In this article, we extend the MT theory to model mixtures containing a pH-sensitive surfactant. The MT theory was validated by examining mixtures containing both a pH-sensitive surfactant and a conventional surfactant, which effectively behave like ternary surfactant mixtures. We first compared the predicted micellar titration data to experimental micellar titration data that we obtained for varying compositions of mixed micelles containing the pH-sensitive surfactant dodecyldimethylamine oxide (C12DAO) mixed with either a cationic surfactant (dodecyltrimethylammonium bromide, C12TAB), a nonionic surfactant (dodecyl octa(ethylene oxide), C12E8), or an anionic surfactant (sodium dodecyl sulfate, SDS) surfactant. The MT theory accurately modeled the titration behavior of C12DAO mixed with C12E8. However, C12DAO was observed to interact more favorably with SDS and with C12TAB than was predicted by the MT theory. We also compared predictions to data from the literature for mixtures of C12DAO and SDS. Although the pH values of solutions with no added acid were modeled with only qualitative accuracy, the MT theory resulted in quantitatively accurate predictions of solution pH for mixtures containing added acid. In addition, the predicted degree of counterion binding yielded a lower bound to the experimentally measured value. Finally, we predicted the critical micelle concentration (cmc) of solutions of two pH-sensitive surfactants, tetradecyldimethylamine oxide (C14DAO) and hexadecyldimethyl betaine (C16Bet), at varying solution pH and surfactant composition. However, at the pH values considered, the pH sensitivity of C16Bet could be neglected, and it was equivalently modeled as a zwitterionic surfactant. The cmc's predicted using the MT theory agreed well with the experimental

  10. Gas-liquid-liquid equilibria in mixtures of water, light gases, and hydrocarbons

    SciTech Connect

    Chao, K.C.

    1990-01-01

    Phase equilibrium in mixtures of water + light gases and water + heavy hydrocarbons has been investigated with the development of new local composition theory, new equations of state, and new experimental data. The preferential segregation and orientation of molecules due to different energies of molecular interaction has been simulated with square well molecules. Extensive simulation has been made for pure square well fluids and mixtures to find the local composition at wide ranges of states. A theory of local composition has been developed and an equation of state has been obtained for square well fluids. The new local composition theory has been embedded in several equations of state. The pressure of water is decoupled into a polar pressure and non-polar pressure according to the molecular model of water of Jorgensen et al. The polar pressure of water is combined with the BACK equation for the general description of polar fluids and their mixtures. Being derived from the steam table, the Augmented BACK equation is particularly suited for mixtures of water + non-polar substances such as the hydrocarbons. The hydrophobic character of the hydrocarbons had made their mixtures with water a special challenge. A new group contribution equation of state is developed to describe phase equilibrium and volumetric behavior of fluids while requiring only to know the molecular structure of the components. 15 refs., 1 fig.

  11. Process and catalyst for converting synthesis gas to liquid hydrocarbon mixture

    DOEpatents

    Rao, V. Udaya S.; Gormley, Robert J.

    1987-01-01

    Synthesis gas containing CO and H.sub.2 is converted to a high-octane hydrocarbon liquid in the gasoline boiling point range by bringing the gas into contact with a heterogeneous catalyst including, in physical mixture, a zeolite molecular sieve, cobalt at 6-20% by weight, and thoria at 0.5-3.9% by weight. The contacting occurs at a temperature of 250.degree.-300.degree. C., and a pressure of 10-30 atmospheres. The conditions can be selected to form a major portion of the hydrocarbon product in the gasoline boiling range with a research octane of more than 80 and less than 10% by weight aromatics.

  12. Preferential adsorption and selective permeation of alcohol/hydrocarbon mixtures in reverse osmosis

    SciTech Connect

    Farnand, B.A.; Sawatzky, H.

    1988-10-01

    In binary mixtures of alcohols and hydrocarbons there are two types of reverse osmosis performances. These are selective permeation of the alcohol and selective permeation of the hydrocarbon. Liquid chromatography results have been used to predict the selective permeation of reverse osmosis membranes where the membranes may be difficult to fabricate as well as to determine performance limits in terms of separation. These results are or interest for the production of oxygenated fuel blending agents where specifications require the removal of unreacted methanol for further processing and distillation is not viable.

  13. A simple method for the titration of multicomponent acid-base mixtures.

    PubMed

    Moisio, T; Heikonen, M

    1996-01-01

    A titration method has been developed to analyze acid mixtures, in which the pK values differed by 0.5 to 1 pH units. Instead of the use of equivalence points a buffer capacity curve is numerically derived from the titration curve resulting in a presentation similar to chromatograms and spectra. The consumption of the NaOH titrant is determined within pH intervals of 0.2-0.6 units around the pK values of the components. The buffer capacity measured is expressed as the consumption of NaOH over the pH interval. The amounts of compounds are found from these results using simple models of chemometrics. The method has been applied to a mixture of formic and acetic acids with concentrations of 0-3 mmol/20 ml with an error of 0-0.05 mmol. Furthermore a curve-fitting method based on a theoretical equation of buffer capacity can be applied with an error slightly larger than with the previous method. In this case, the pK values were also computed. For titrations beyond the pH range 4-10, the buffer capacity of water has to be subtracted from the titration results. The whole procedure requires including the computations about 3-6 min.

  14. Analysis of siloxanes in hydrocarbon mixtures using comprehensive two-dimensional gas chromatography.

    PubMed

    Ghosh, Abhijit; Seeley, Stacy K; Nartker, Steven R; Seeley, John V

    2014-09-19

    A comprehensive two-dimensional gas chromatography (GC×GC) method for separating siloxanes from hydrocarbons has been developed using a systematic process. First, the retention indices of a set of siloxanes and a set of hydrocarbons were determined on 6 different stationary phases. The retention indices were then used to model GC×GC separation on 15 different stationary phase pairs. The SPB-Octyl×DB-1 pair was predicted to provide the best separation of the siloxanes from the hydrocarbons. The efficacy of this stationary phase pair was experimentally tested by performing a GC×GC analysis of gasoline spiked with siloxanes and by analyzing biogas obtained from a local wastewater treatment facility. The model predictions agreed well with the experimental results. The SPB-Octyl×DB-1 stationary phase pair constrained the hydrocarbons to a narrow range of secondary retention times and fully isolated the siloxanes from the hydrocarbon band. The resulting GC×GC method allows siloxanes to be resolved from complex mixtures of hydrocarbons without requiring the use of a selective detector.

  15. Ultrafast photophysical studies of a multicomponent sunscreen: Oxybenzone-titanium dioxide mixtures

    NASA Astrophysics Data System (ADS)

    Baker, Lewis A.; Grosvenor, Lucy C.; Ashfold, Michael N. R.; Stavros, Vasilios G.

    2016-11-01

    Recent studies of the sunscreen constituent oxybenzone have suggested that the dominant mechanism underlying the efficient photoprotection it offers relies on an initial ultrafast enol → keto tautomerisation, followed by nonadiabatic transfer to the ground electronic state. Subsequent collisions with the solvent bath then reform the original enol-tautomer. Utilising femtosecond transient electronic absorption spectroscopy we explore the dissipation of electronic excitation energy in oxybenzone in the presence of titanium dioxide, a widely used, and complementary sunscreen component. We find the relaxation dynamics of this popular organic filter are unaltered by the presence of this favoured inorganic scatterer and the overall dynamics can be described by the additive contribution of the individual constituents. The combination of the two components provides broadband photoprotective properties justifying the widely used organic filter and inorganic scatterer mixtures in commercial sunscreen products.

  16. On-Line Measurement of Heat of Combustion of Gaseous Hydrocarbon Fuel Mixtures

    NASA Technical Reports Server (NTRS)

    Sprinkle, Danny R.; Chaturvedi, Sushil K.; Kheireddine, Ali

    1996-01-01

    A method for the on-line measurement of the heat of combustion of gaseous hydrocarbon fuel mixtures has been developed and tested. The method involves combustion of a test gas with a measured quantity of air to achieve a preset concentration of oxygen in the combustion products. This method involves using a controller which maintains the fuel (gas) volumetric flow rate at a level consistent with the desired oxygen concentration in the combustion products. The heat of combustion is determined form a known correlation with the fuel flow rate. An on-line computer accesses the fuel flow data and displays the heat of combustion measurement at desired time intervals. This technique appears to be especially applicable for measuring heats of combustion of hydrocarbon mixtures of unknown composition such as natural gas.

  17. Biodegradation kinetics of select polycyclic aromatic hydrocarbon (PAH) mixtures by Sphingomonas paucimobilis EPA505.

    PubMed

    Desai, Anuradha M; Autenrieth, Robin L; Dimitriou-Christidis, Petros; McDonald, Thomas J

    2008-04-01

    Many contaminated sites commonly have complex mixtures of polycyclic aromatic hydrocarbons (PAHs) whose individual microbial biodegradation may be altered in mixtures. Biodegradation kinetics for fluorene, naphthalene, 1,5-dimethylnaphthalene and 1-methylfluorene were evaluated in sole substrate, binary and ternary systems using Sphingomonas paucimobilis EPA505. The first order rate constants for fluorene, naphthalene, 1,5-dimethylnaphthalene, and 1-methylfluorene were comparable; yet Monod parameters were significantly different for the tested PAHs. S. paucimobilis completely degraded all the components in binary and ternary mixtures; however, the initial degradation rates of individual components decreased in the presence of competitive PAHs. Results from the mixture experiments indicate competitive interactions, demonstrated mathematically. The generated model appropriately predicted the biodegradation kinetics in mixtures using parameter estimates from the sole substrate experiments, validating the hypothesis of a common rate-determining step. Biodegradation kinetics in mixtures were affected by the affinity coefficients of the co-occurring PAHs and mixture composition. Experiments with equal concentrations of substrates demonstrated the effect of concentration on competitive inhibition. Ternary experiments with naphthalene, 1,5-dimethylnaphthalene and 1-methylfluorene revealed delayed degradation, where depletion of naphthalene and 1,5-dimethylnapthalene occurred rapidly only after the complete removal of 1-methylfluorene. The substrate interactions observed in mixtures require a multisubstrate model to account for simultaneous degradation of substrates. PAH contaminated sites are far more complex than even ternary mixtures; however these studies clearly demonstrate the effect that interactions can have on individual chemical kinetics. Consequently, predicting natural or enhanced degradation of PAHs cannot be based on single compound kinetics as this

  18. DETERMINATION OF SOLID-LIQUID EQUILIBRIA DATA FOR MIXTURES OF HEAVY HYDROCARBONS IN A LIGHT SOLVENT

    SciTech Connect

    F.V. Hanson; J.V. Fletcher; Karthik R.

    2003-06-01

    A methodology was developed using an FT-IR spectroscopic technique to obtain solid-liquid equilibria (SLE) data for mixtures of heavy hydrocarbons in significantly lighter hydrocarbon diluents. SLE was examined in multiple Model Oils that were assembled to simulate waxes. The various Model oils were comprised of C-30 to C-44 hydrocarbons in decane. The FT-IR technique was used to identify the wax precipitation temperature (WPT). The DSC technique was also used in the identification of the onset of the two-phase equilibrium in this work. An additional Model oil made up of C-20 to C-30 hydrocarbons in decane was studied using the DSC experiment. The weight percent solid below the WPT was calculated using the FT-IR experimental results. The WPT and the weight percent solid below the WPT were predicted using an activity coefficient based thermodynamic model. The FT-IR spectroscopy method is found to successfully provide SLE data and also has several advantages over other laboratory-based methods.

  19. Wettability of polymeric solids by ternary mixtures composed of hydrocarbon and fluorocarbon nonionic surfactants.

    PubMed

    Szymczyk, Katarzyna

    2011-11-01

    Contact angle (θ) measurements on poly(tetrafluoroethylene) (PTFE) and polymethyl methacrylate (PMMA) surface were carried out for the systems containing ternary mixtures of surfactants composed of: p-(1,1,3,3-tetramethylbutyl)phenoxypoly(ethylene glycols), Triton X-100 (TX100), Triton X-165 (TX165) and Triton X-114 (TX114), and fluorocarbon surfactants, Zonyl FSN100 (FSN100) and Zonyl FSO100 (FSO100). The aqueous solutions of ternary surfactant mixtures were prepared by adding TX114, FSN100 or FSO100 to binary mixtures of TX100+TX165, where the synergistic effect in the reduction of the surface tension of water (γ(LV)) was determined. From the obtained contact angle values, the relationships between cosθ, the adhesion tension and surface tension of solutions, cosθ and the reciprocal of the surface tension were determined. On the basis of these relationships, the correlation between the critical surface tension of PTFE and PMMA wetting and the surface tension of these polymers as well as the work of adhesion of aqueous solutions of ternary surfactant mixtures to PTFE and PMMA surface were discussed. The critical surface tension of PTFE and PMMA wetting, γ(C), determined from the contact angle measurements of aqueous solutions of surfactants including FSN100 or FSO100 was also discussed in the light of the surface tension changes of PTFE and PMMA under the influence of film formation by fluorocarbon surfactants on the surface of these polymers. The γ(C) values of the studied polymeric solids were found to be different for the mixtures composed of hydrocarbon surfactants in comparison with those of hydrocarbon and fluorocarbon surfactants. In the solutions containing fluorocarbon surfactants, the γ(C) values were different taking into account the contact angle in the range of FSN100 and FSO100 concentration corresponding to their unsaturated monolayer at water-air interface or to that saturated.

  20. Modeling of thermodiffusion experiments for hydrocarbon mixtures and water-alcohol mixtures On Board FOTON M3

    NASA Astrophysics Data System (ADS)

    Saghir, Ziad; Saghir, Ziad; Yan, Yu; Ezzatian, Pouyan; Jaber, Tawfic

    Thermodiffusion experiments have been conducted on board FOTON Soyuz rocket in September 2007. The space hardware used is developed by the European Space Agency. And the TOTAL Oil Company in France is currently in the progress of data analysis. On the numerical side, we have modeled the thermodiffusion experiments for hydrocarbon mixtures containing methane, n-butane and dodecane in 6mm experimental cells and a water-isopropanol mixture in 12mm experimental cells. Two types of scenarios have been considered in the numerical modeling: (1) static 10-6g0; and (2) FOTON-12 TRAMP. Scenario (1) may be regarded as a "perfect" condition that a space experiment can possibly achieve. Scenario (2) may be regarded as a "real" condition. Numerical results, e.g., thermodiffusion coefficient, temperature, concentration etc., under both scenarios will be presented and discussed in detail. Based on the numerical results, average thermodiffusion coefficients at both hot and cold side of the experimental cell can be derived. These results may be compared with the space experimental data in the near future upon the availability.

  1. New design of fiber-optic reflectometer for determining the phase boundary of multicomponent fluid mixtures at high pressures and high temperatures

    NASA Astrophysics Data System (ADS)

    Wu, Weize; Ke, Jie; Poliakoff, Martyn

    2006-02-01

    A dynamic synthetic method based on an optic fiber sensor has been developed to measure phase boundaries of multicomponent fluid at high temperatures >300°C and pressures >30MPa. The breakthrough has been the design of the equilibrium cell containing the optic fiber, which gives highly reproducible signals for the phase transition. We demonstrate that this method can clearly distinguish between dew points and bubble points in the phase transitions of mixtures. Overall, the method is characterized by speed, simplicity, high pressures, and high temperatures.

  2. Detection of exposure effects of mixtures of heavy polycyclic aromatic hydrocarbons in zebrafish embryos.

    PubMed

    Barranco, Alejandro; Escudero, Laura; Sanz Landaluze, Jon; Rainieri, Sandra

    2017-03-01

    In this study we evaluated the exposure effects of mixtures of five polycyclic aromatic hydrocarbons (PAHs); namely, benzo[a]anthracene, benzo[a]pyrene, benzo[b]fluoranthene, benzo[k]fluoranthene and chrysene on zebrafish embryos. Supplementation of the exposure media with 0.45% dimethyl sulfoxide and 50 ppm of Tween 20 could guarantee the solubilization and stabilization of the PAHs up to 24 h without affecting the embryos development. The exposure effects were tested by detecting the differential expression of a number of genes related to the aryl hydrocarbon receptor gene battery. Effects were detectable already after 6 h of exposure. After 24 h of exposure, all PAHs, except for benzo[a]anthracene, acted as potent inducers of the gene cyp1a1. Benzo[k]fluoranthene was the major inducer; the effect caused by the mixture at the lower concentration tested (1 ng ml(-1) ) was dominated by its presence. However, in the mixture at the highest concentration tested (10 ng ml(-1) ) it caused less induction and was not dominant. No significant bioaccumulation values were detected on embryos exposed to the PAHs tested in this study; however, the results obtained, indicated that PAHs undergo a very rapid metabolization inside the embryos, and that those biotransformation products yield changes on the expression of genes involved in the aryl hydrocarbon receptor pathway. Future work should focus on identification of the PAH metabolization products and on the effect of these metabolites on toxicity. Copyright © 2016 John Wiley & Sons, Ltd.

  3. Additive toxicity of binary mixtures of phototoxic polycyclic aromatic hydrocarbons to the oligochaete Lumbriculus variegatus.

    PubMed

    Erickson, R J; Ankley, G T; DeFoe, D L; Kosian, P A; Makynen, E A

    1999-01-01

    Toxicity of some polycyclic aromatic hydrocarbons (PAHs) can increase by an order of magnitude, or more, in the presence of solar ultraviolet (UV) radiation. In the environment, PAHs exist as complex mixtures, which generally would include multiple PAHs that could cause photoinduced toxicity. Hence, to accurately predict the potential ecological risk of phototoxic PAHs, it is critical to understand their joint toxicity. In this study, we exposed the oligochaete Lumbriculus variegatus to the phototoxic PAHs anthracene, fluoranthene, and pyrene, both singly and as binary mixtures for 96 h. Following this, the animals were exposed to UV light for an additional 96 h, during which periodic observations of mortality were made. Time-dependent phototoxicity of the binary PAH mixtures, expressed as a function of the product of UV light intensity and PAH dose (in the tissue of the animals), was adequately described using a concentration addition model. Given the probability that the PAHs examined acted via a common mechanism of action, this result was consistent with expectations. These data highlight the need to consider the combined photoactivation potential of PAH mixtures and provide the technical basis for a modeling approach to predict their ecological risk.

  4. Photoactivation and toxicity of mixtures of polycyclic aromatic hydrocarbon compounds in marine sediment

    SciTech Connect

    Swartz, R.C.; Ferraro, S.P.; Lamberson, J.O.; Cole, F.A.; Ozretich, R.J.; Boese, B.L.; Schults, D.W.; Behrenfeld, M.; Ankley, G.T.

    1997-10-01

    The direct toxicity and photoinduced toxicity of sediment-associated acenaphthene, phenanthrene, fluoranthene, and pyrene were determined for the marine amphipod Rhepoxynius abronius. The four polycyclic aromatic hydrocarbons (PAHs) were spiked into sediment in a concentration series of either single compounds or as approximately equitoxic mixtures of all four compounds. Standard 10-d sediment toxicity tests were conducted under fluorescent lighting. After 10 d, survivors were exposed for 1 h to ultraviolet (UV) radiation in the absence of sediment and then tested for their ability to bury in uncontaminated sediment. The 10-d median lethal concentrations (LC50s) were 2.31 mg acenaphthene/g organic carbon (OC), 2.22 mg phenanthrene/g OC, 3.31 mg fluoranthene/g OC, and 2.81 mg pyrene/g OC. These LC50s were used to calculate the sum of toxic units ({Sigma}TU) of the four PAHs in the approximately equitoxic mixtures. The {Sigma}TU LC50 was then calculated for the mixture treatments. If the toxicologic interaction of a mixture of contaminants is additive, {Sigma}TU LC50 = 1.0. The observed LC50 (1.55 {Sigma}TU) was slightly, but significantly, greater than unity, indicating that the interaction of PAHs in the mixture was less than additive. Exposure to UV radiation enhanced the toxic effects of fluoranthene and pyrene, but did not affect the toxicity of acenaphthene and phenanthrene. Effects of UV radiation on the toxicity of the mixture of four PAHs could be explained by the photoactivation of fluoranthene and pyrene alone. These results are consistent with predictions based on photophysical properties of PAH compounds.

  5. Analysis of binary mixtures of aqueous aromatic hydrocarbons with low-phase-noise shear-horizontal surface acoustic wave sensors using multielectrode transducer designs.

    PubMed

    Bender, Florian; Mohler, Rachel E; Ricco, Antonio J; Josse, Fabien

    2014-11-18

    The present work investigates a compact sensor system that provides rapid, real-time, in situ measurements of the identities and concentrations of aromatic hydrocarbons at parts-per-billion concentrations in water through the combined use of kinetic and thermodynamic response parameters. The system uses shear-horizontal surface acoustic wave (SH-SAW) sensors operating directly in the liquid phase. The 103 MHz SAW sensors are coated with thin sorbent polymer films to provide the appropriate limits of detection as well as partial selectivity for the analytes of interest, the BTEX compounds (benzene, toluene, ethylbenzene, and xylenes), which are common indicators of fuel and oil accidental releases in groundwater. Particular emphasis is placed on benzene, a known carcinogen and the most challenging BTEX analyte with regard to both regulated levels and its solubility properties. To demonstrate the identification and quantification of individual compounds in multicomponent aqueous samples, responses to binary mixtures of benzene with toluene as well as ethylbenzene were characterized at concentrations below 1 ppm (1 mg/L). The use of both thermodynamic and kinetic (i.e., steady-state and transient) responses from a single polymer-coated SH-SAW sensor enabled identification and quantification of the two BTEX compounds in binary mixtures in aqueous solution. The signal-to-noise ratio was improved, resulting in lower limits of detection and improved identification at low concentrations, by designing and implementing a type of multielectrode transducer pattern, not previously reported for chemical sensor applications. The design significantly reduces signal distortion and root-mean-square (RMS) phase noise by minimizing acoustic wave reflections from electrode edges, thus enabling limits of detection for BTEX analytes of 9-83 ppb (calculated from RMS noise); concentrations of benzene in water as low as ~100 ppb were measured directly. Reliable quantification of BTEX

  6. Adsorption of binary hydrocarbon mixtures in carbon slit pores: A density functional theory study

    SciTech Connect

    Bhatia, S.K.

    1998-10-13

    Adsorption of binary hydrocarbons mixtures involving methane in carbon slit pores is theoretically studied here from the viewpoints of separation and of the effect of impurities on methane storage. It is seen that even small amounts of ethane, propane, or butane can significantly reduce the methane capacity of carbons. Optimal pore sizes and pressures, depending on impurity concentration, are noted in the present work, suggesting that careful adsorbent and process design can lead to enhanced separation. These results are consistent with earlier literature studies for the infinite dilution limit. For methane storage applications a carbon micropore width of 11.4 {angstrom} (based on distance between centers of carbon atoms on opposing walls) is found to be the most suitable from the point of view of lower impurity uptake during high-pressure adsorption and greater impurity retention during low-pressure delivery. The results also theoretically confirm unusual recently reported observations of enhanced methane adsorption in the presence of a small amount of heavier hydrocarbon impurity.

  7. Improved Resolution of Hydrocarbon Structures and Constitutional Isomers in Complex Mixtures Using Gas Chromatography-Vacuum Ultraviolet-Mass Spectrometry

    SciTech Connect

    Isaacman, Gabriel; Wilson, Kevin R.; Chan, Arthur W. H.; Worton, David R.; Kimmel, Joel R.; Nah, Theodora; Hohaus, Thorsten; Gonin, Marc; Kroll, Jesse H.; Worsnop, Douglas R.; Goldstein, Allen H.

    2012-01-30

    Understanding the composition of complex hydrocarbon mixtures is important for environmental studies in a variety of fields, but many prevalent compounds cannot be confidently identified using traditional gas chromatography/mass spectrometry (GC/MS) techniques. In this study, we use vacuum-ultraviolet (VUV) ionization to elucidate the structures of a traditionally “unresolved complex mixture” by separating components by GC retention time, tR, and mass-to-charge ratio, m/z, which are used to determine carbon number, NC, and the number of rings and double bonds, NDBE. Constitutional isomers are resolved on the basis of tR, enabling the most complete quantitative analysis to date of structural isomers in an environmentally relevant hydrocarbon mixture. Unknown compounds are classified in this work by carbon number, degree of saturation, presence of rings, and degree of branching, providing structural constraints. The capabilities of this analysis are explored using diesel fuel, in which constitutional isomer distribution patterns are shown to be reproducible between carbon numbers and follow predictable rules. Nearly half of the aliphatic hydrocarbon mass is shown to be branched, suggesting branching is more important in diesel fuel than previously shown. Lastly, the classification of unknown hydrocarbons and the resolution of constitutional isomers significantly improves resolution capabilities for any complex hydrocarbon mixture.

  8. Laboratory Analysis Of Water, Hydrocarbon And Ammonia Ice Mixtures Exposed To High-energy Electron Irradiation

    NASA Astrophysics Data System (ADS)

    Hand, Kevin P.; Carlson, R. W.; Tsapin, A. I.

    2006-09-01

    Irradiation of low temperature ices in the laboratory provides insight into processes that may be occurring on icy bodies in the solar system. Here we report on results from high-energy (10keV) electron irradiation of thin ice films at 1e-8 torr and 70-120K. Mixtures include water with CO2, C3H8, C3H6, C4H10 (butane and isobutane), C4H8,(1-butene and cis/trans-2-butene), and NH3. During irradiation of H2O + alkane films at 80K, CO2 and CH4 production is observed and both species are retained in the ice, possibly trapped in clathrates. The -CH3 infrared bands initially present are seen to decrease with increasing dose. Bands associated with -CH2- persist, indicating polymerization of the initial short-chain hydrocarbons. In alkenes a similar evolution toward polymerization is observed, however the first step appears to be the destruction of the C=C bond. Upon warming of the film, mass spectra data compliment the mid-infrared data and indicate the production of H2CO, however glycolic acid is not explicitly seen in the mass spectra. When warmed to 300K, residues remained for all irradiated films except that of the H2O + CO2 mixtures. Residues were analyzed with Matrix Assisted Laser Desorption/Ionization Mass Spectrometry (MALDI). Results show the production of large aliphatic, very refractory, hydrocarbons (with m/z up to 2500). Mid-infrared spectra of the residues indicate carbonyls and alcohols, likely due to polymerized aldehydes and carboxylic acids. Films of H2O + C3H8 + NH3 at 70K show the production of OCN- (cyanate ion), formamide, along with other possible amides and hydrocarbons. HPLC results indicate the production of racemic alanine. Finally, results of abiotic experiments are compared to results from the irradiation of bacterial spores in ice. The application to Europa and Enceladus is discussed.

  9. Developing Mathematical Provisions for Assessment of Liquid Hydrocarbon Emissions in Emergency Situations

    NASA Astrophysics Data System (ADS)

    Zemenkova, M. Yu; Zemenkov, Yu D.; Shantarin, V. D.

    2016-10-01

    The paper reviews the development of methodology for calculation of hydrocarbon emissions during seepage and evaporation to monitor the reliability and safety of hydrocarbon storage and transportation. The authors have analyzed existing methods, models and techniques for assessing the amount of evaporated oil. Models used for predicting the material balance of multicomponent two-phase systems have been discussed. The results of modeling the open-air hydrocarbon evaporation from an oil spill are provided and exemplified by an emergency pit. Dependences and systems of differential equations have been obtained to assess parameters of mass transfer from the open surface of a liquid multicomponent mixture.

  10. Development of a Relative Potency Factor (Rpf) Approach for Polycyclic Aromatic Hydrocarbon (PAH) Mixtures (External Review Draft)

    EPA Science Inventory

    EPA is conducting a peer review and public comment of the scientific basis supporting the human health hazard and dose-response assessment of polycyclic aromatic hydrocarbon (PAH) mixtures that when finalized will appear on the Integrated Risk Information System (IRIS) database. ...

  11. Assessment of toxic interactions of heavy metals in multi-component mixtures using sea urchin embryo-larval bioassay.

    PubMed

    Xu, Xue; Li, Yan; Wang, Yuan; Wang, Yonghua

    2011-02-01

    The toxicities of copper, lead, zinc and cadmium ions and various concentrations of mixtures of them were studied using sea urchin (Strongylocentyotus intermedius) embryo-larval bioassay. Toxic unit analysis was used to determine type of joint action for each mixture combination (binary, ternary and quaternary). For the majority of the binary combinations, the interactions were of synergistic nature, but in ternary or quaternary mixtures, the joint action was mainly concentration additive, while antagonism was only observed for two mixtures (Cu+Pb and Zn+Cd) among all the 11 combinations. Two prevailing theoretical models: the concentration addition (CA) model and the independent action (IA) model were used to predict the mixture toxicities. The weak correlation obtained (R≃0.55) indicated that the hypotheses of mode of action involved in the two models to some extent failed to describe the behavior of the mixture system. Then a novel bio-concentration factor-based model was developed and was successful to predict the toxicities of mixtures, with an obtained R of 0.92. This model indicated that in a mixture system of heavy metals, the joint toxicity was mainly determined by the combined action of bio-concentrations of metals other than the simply similar (CA) or dissimilar (IA) modes of action of the mixture components.

  12. Importance of Aqueous-phase Secondary Organic Aerosol Formation from Aromatics in an Atmospheric Hydrocarbon Mixture

    NASA Astrophysics Data System (ADS)

    Parikh, H. M.; Carlton, A. G.; Vizuete, W.; Zhang, H.; Zhou, Y.; Chen, E.; Kamens, R. M.

    2010-12-01

    Two new secondary organic aerosol (SOA) modeling frameworks are developed, one based on an aromatic gas and particle-phase kinetic mechanism and another based on a parameterized SOA model used in conjunction with an underlying gas-phase mechanism, both of which simulate SOA formation through partitioning to two stable liquid phases: one hydrophilic containing particle aqueous-phase and the other hydrophobic comprising mainly organic components. The models were evaluated against outdoor smog chamber experiments with different combinations of initial toluene, o-xylene, p-xylene, toluene and xylene mixtures, NOx, non-SOA-forming hydrocarbon mixture, initial seed type, and humidity. Aerosol data for experiments with either ammonium sulfate or initial background seed particles, in the presence of an atmospheric hydrocarbon mixture, NOx and in sunlight under a dry atmosphere (RH = 6 to 10%) show reduced SOA formation when compared to experiments with similar initial gas and particle concentrations at higher relative humidities (RH = 40 to 90%). Both frameworks simulated reasonable fits to the total observed SOA concentrations under all conditions. For both dry and wet experiments with low initial seed, semi-volatile product partitioning in particle organic-phase is mass-transfer limited and is modeled using a dynamic gas-particle partitioning algorithm with accommodation coefficient as the primary pseudo-transport parameter. Further, the modeled SOA product distributions for both frameworks clearly show the importance of the contribution of aqueous-phase SOA particularly under conditions of low initial seed concentrations and high-humidity. For both models, under these conditions, aqueous-phase SOA from uptake of glyoxal, methylglyoxal and related polar products to particle water phase dominates as compared to the partitioning of semi-volatiles to particle organic phase. Interestingly, both the kinetic and parameterized SOA frameworks simulate similar amounts of aqueous

  13. A new developed velocity of sound measurement device for characterization of multi-component gas mixtures under elevated temperatures and pressures

    NASA Astrophysics Data System (ADS)

    Seibel, C.; Suedmeyer, J.; Fieback, T. M.

    2014-07-01

    Inline process control by measurement of velocity of sound of fluids is a direct and comprehensive technique [J. D. N. Cheeke and Z. Wang, "Acoustic wave gas sensors," Sens. Actuators B 59, 146-153 (1999); J. W. Grate, S. J. Martin, and R. M. White, "Acoustic wave microsensors," Anal. Chem. 65, 1868 (1993)]. Depending on the varying conditions of measuring fluid(s), temperatures and pressures, it is a challenging task to find the best possible acoustic setup. Taking this background into account, a velocity of sound measurement device for temperatures up to 475 K and pressures up to 24 MPa was designed and assembled that is to be used for testing different resonator types. Two bulk acoustic wave resonators out of the commonly used lead zirconatetitanate compound (PZT) were tested at different test fluids under temperatures up to 423.15 K and pressures up to 24 MPa [S. Gebhardt, L. Seffner, F. Schlenkirch, and A. Schönecker, "PZT thick films for sensor and actuator applications," J. Eur. Ceram. Soc. 27, 4177-4180 (2007)]. Initially the pure gases methane, ethane, carbon dioxide, nitrogen, and helium were measured, followed by multi-component gas mixtures. Beside methane-based binary and ternary gas mixtures, a quaternary gas mixture comprising methane, ethane, carbon dioxide, and helium was analyzed. Results for all measurement fluids in a broad temperature and pressure range show a relative deviation to theoretical values derived from GERG-2008 smaller than 0.5%.

  14. Use of pruned computational neural networks for processing the response of oscillating chemical reactions with a view to analyzing nonlinear multicomponent mixtures.

    PubMed

    Hervás, C; Toledo, R; Silva, M

    2001-01-01

    The suitability of pruned computational neural networks (CNNs) for resolving nonlinear multicomponent systems involving synergistic effects by use of oscillating chemical reaction-based methods implemented using the analyte pulse perturbation technique is demonstrated. The CNN input data used for this purpose are estimates provided by the Levenberg-Marquardt method in the form of a three-parameter Gaussian curve associated with the singular profile obtained when the oscillating system is perturbed by an analyte mixture. The performance of the proposed method was assessed by applying it to the resolution of mixtures of pyrogallol and gallic acid based on their perturbating effect on a classical oscillating chemical system, viz. the Belousov-Zhabotinskyi reaction. A straightforward network topology (3:3:2, with 18 connections after pruning) allowed the resolution of mixtures of the two analytes in concentration ratios from 1:7 to 6:2 with a standard error of prediction for the testing set of 4.01 and 8.98% for pyrogallol and gallic acid, respectively. The reduced dimensions of the selected CNN architecture allowed a mathematical transformation of the input vector into the output one that can be easily implemented via software. Finally, the suitability of response surface analysis as an alternative to CNNs was also tested. The results were poor (relative errors were high), which confirms that properly selected pruned CNNs are effective tools for solving the analytical problem addressed in this work.

  15. A new developed velocity of sound measurement device for characterization of multi-component gas mixtures under elevated temperatures and pressures.

    PubMed

    Seibel, C; Suedmeyer, J; Fieback, T M

    2014-07-01

    Inline process control by measurement of velocity of sound of fluids is a direct and comprehensive technique [J. D. N. Cheeke and Z. Wang, "Acoustic wave gas sensors," Sens. Actuators B 59, 146-153 (1999); J. W. Grate, S. J. Martin, and R. M. White, "Acoustic wave microsensors," Anal. Chem. 65, 1868 (1993)]. Depending on the varying conditions of measuring fluid(s), temperatures and pressures, it is a challenging task to find the best possible acoustic setup. Taking this background into account, a velocity of sound measurement device for temperatures up to 475 K and pressures up to 24 MPa was designed and assembled that is to be used for testing different resonator types. Two bulk acoustic wave resonators out of the commonly used lead zirconatetitanate compound (PZT) were tested at different test fluids under temperatures up to 423.15 K and pressures up to 24 MPa [S. Gebhardt, L. Seffner, F. Schlenkirch, and A. Schönecker, "PZT thick films for sensor and actuator applications," J. Eur. Ceram. Soc. 27, 4177-4180 (2007)]. Initially the pure gases methane, ethane, carbon dioxide, nitrogen, and helium were measured, followed by multi-component gas mixtures. Beside methane-based binary and ternary gas mixtures, a quaternary gas mixture comprising methane, ethane, carbon dioxide, and helium was analyzed. Results for all measurement fluids in a broad temperature and pressure range show a relative deviation to theoretical values derived from GERG-2008 smaller than 0.5%.

  16. Metal-Polycyclic Aromatic Hydrocarbon Mixture Toxicity in Hyalella azteca. 1. Response Surfaces and Isoboles To Measure Non-additive Mixture Toxicity and Ecological Risk.

    PubMed

    Gauthier, Patrick T; Norwood, Warren P; Prepas, Ellie E; Pyle, Greg G

    2015-10-06

    Mixtures of metals and polycyclic aromatic hydrocarbons (PAHs) occur ubiquitously in aquatic environments, yet relatively little is known regarding their potential to produce non-additive toxicity (i.e., antagonism or potentiation). A review of the lethality of metal-PAH mixtures in aquatic biota revealed that more-than-additive lethality is as common as strictly additive effects. Approaches to ecological risk assessment do not consider non-additive toxicity of metal-PAH mixtures. Forty-eight-hour water-only binary mixture toxicity experiments were conducted to determine the additive toxic nature of mixtures of Cu, Cd, V, or Ni with phenanthrene (PHE) or phenanthrenequinone (PHQ) using the aquatic amphipod Hyalella azteca. In cases where more-than-additive toxicity was observed, we calculated the possible mortality rates at Canada's environmental water quality guideline concentrations. We used a three-dimensional response surface isobole model-based approach to compare the observed co-toxicity in juvenile amphipods to predicted outcomes based on concentration addition or effects addition mixtures models. More-than-additive lethality was observed for all Cu-PHE, Cu-PHQ, and several Cd-PHE, Cd-PHQ, and Ni-PHE mixtures. Our analysis predicts Cu-PHE, Cu-PHQ, Cd-PHE, and Cd-PHQ mixtures at the Canadian Water Quality Guideline concentrations would produce 7.5%, 3.7%, 4.4% and 1.4% mortality, respectively.

  17. Effects of petroleum mixture types on soil bacterial population dynamics associated with the biodegradation of hydrocarbons in soil environments.

    PubMed

    Hamamura, Natsuko; Ward, David M; Inskeep, William P

    2013-07-01

    Soil bacterial population dynamics were examined to assess patterns in microbial response to contamination by different petroleum mixtures with variation in n-alkane profiles or toxic constituents such as pentachlorophenol (PCP). Three soil types from distinct areas of the United States (Montana, Oregon, and Arizona) were used in controlled perturbation experiments containing crude oil, kerosene, diesel, or diesel plus PCP spiked with (14)C-hexadecane or (14)C-tridecane. After a 50-day incubation, 30-70% of added (14)C-alkanes were mineralized to (14)CO₂ in Montana and Oregon soils. In contrast, significantly lower mineralization was observed with diesel or kerosene (< 5%) compared to crude-oil treatment (~45%) in the Arizona soil. Different hydrocarbon mixtures selected both unique and common microbial populations across all three soils. Conversely, the contamination of different soils with the same mixture selected for distinct microbial populations. The most consistent genotype observed, a Rhodococcus-like population, was present in the Montana soil with all mixture types. The addition of PCP selected for PCP-tolerant alkane-degrading specialist populations. The results indicated that petroleum mixture type influenced hydrocarbon degradation rates and microbial population selection and that soil characteristics, especially organic content, could also be an important determinant of community responses to hydrocarbon perturbation.

  18. CO{sub 2}/dimethyl ether (DME) feed mixtures in the DME-to-hydrocarbon (DTH) process

    SciTech Connect

    Sardesai, A.; Tartamella, T.; Lee, S.

    1995-12-31

    The DTH process represents the second stage in the conversion of syngas to hydrocarbons, where DME produced from the LPDME process is converted to C{sub 1}-C{sub 10} range hydrocarbons over a zeolite type catalyst in a fixed-bed tubular reactor. The reaction occurs in the vapor phase and typically operates at a temperature of 375 C. The product distribution can be can be controlled by varying the operating temperature, pressure and space velocity of DME. Previous investigations have examined the effects of T, P, WHSV, and catalyst type on olefin productivity as well as the processing advantages in starting with DME rather than MeOH. Unreacted CO{sub 2} from the DME synthesis reactor represents a potential problem in terms of further hydrocarbon processing from a DME feedstock; CO{sub 2}/DME mixtures are difficult to separate. A productivity comparison has been made with runs containing feed mixtures of CO{sub 2}/DME and N{sub 2}/DME mixtures. The role of CO{sub 2} on the final product distribution in the DTH process as well as the potential for recycle of unreacted CO{sub 2} back to the DME synthesis reactor has been examined. It has been found that CO{sub 2} is not actively involved in the reaction kinetics for the conversion of DME to hydrocarbons. Product distributions of the gaseous product are similar to those where N{sub 2} was used as the diluent.

  19. Removal of polycyclic aromatic hydrocarbons in soil spiked with model mixtures of petroleum hydrocarbons and heterocycles using biosurfactants from Rhodococcus ruber IEGM 231.

    PubMed

    Ivshina, Irina; Kostina, Ludmila; Krivoruchko, Anastasiya; Kuyukina, Maria; Peshkur, Tatyana; Anderson, Peter; Cunningham, Colin

    2016-07-15

    Removal of polycyclic aromatic hydrocarbons (PAHs) in soil using biosurfactants (BS) produced by Rhodococcus ruber IEGM 231 was studied in soil columns spiked with model mixtures of major petroleum constituents. A crystalline mixture of single PAHs (0.63g/kg), a crystalline mixture of PAHs (0.63g/kg) and polycyclic aromatic sulfur heterocycles (PASHs), and an artificially synthesized non-aqueous phase liquid (NAPL) containing PAHs (3.00g/kg) dissolved in alkanes C10-C19 were used for spiking. Percentage of PAH removal with BS varied from 16 to 69%. Washing activities of BS were 2.5 times greater than those of synthetic surfactant Tween 60 in NAPL-spiked soil and similar to Tween 60 in crystalline-spiked soil. At the same time, amounts of removed PAHs were equal and consisted of 0.3-0.5g/kg dry soil regardless the chemical pattern of a model mixture of petroleum hydrocarbons and heterocycles used for spiking. UV spectra for soil before and after BS treatment were obtained and their applicability for differentiated analysis of PAH and PASH concentration changes in remediated soil was shown. The ratios A254nm/A288nm revealed that BS increased biotreatability of PAH-contaminated soils.

  20. Development and validation of chemometrics-assisted spectrophotometry and liquid chromatography methods for the simultaneous determination of the active ingredients in two multicomponent mixtures containing chlorpheniramine maleate and phenylpropanolamine hydrochloride.

    PubMed

    Hadad, Ghada M; El-Gindy, Alaa; Mahmoud, Waleed M M

    2007-01-01

    Multivariate spectrophotometric calibration and liquid chromatography (LC) methods were used for the simultaneous determination of the active ingredients in 2 multicomponent mixtures containing chlorpheniramine maleate and phenylpropanolamine hydrochloride with ibuprofen and caffeine (mixture 1) or with propyphenazone (mixture 2). For the multivariate spectrophotometric calibration methods, principal component regression (PCR) and partial least squares (PLS-1), a calibration set of the mixtures consisting of the components of each mixture was prepared in distilled water. A leave-1-out cross-validation procedure was used to find the optimum numbers of latent variables. Analytical parameters such as sensitivity, selectivity, analytical sensitivity, limit of quantitation, and limit of detection were determined for both PLS-1 and PCR. The LC method depends on the use of a cyanopropyl column with the mobile phase acetonitrile-12 mM ammonium acetate, pH 5.0 (25 + 75, v/v), for mixture 1 or acetonitrile-10 mM potassium dihydrogen phosphate, pH 4.7 (45 + 55, v/v), for mixture 2; the UV detector was set at 212 nm. In spite of the presence of a high degree of spectral overlap of these components, they were rapidly and simultaneously determined with high accuracy and precision, with no interference from the matrix excipients. The proposed methods were successfully applied to the analysis of pharmaceutical formulations and laboratory-prepared mixtures containing the 2 multicomponent combinations.

  1. Passive dosing of polycyclic aromatic hydrocarbon (PAH) mixtures to terrestrial springtails: linking mixture toxicity to chemical activities, equilibrium lipid concentrations, and toxic units.

    PubMed

    Schmidt, Stine N; Holmstrup, Martin; Smith, Kilian E C; Mayer, Philipp

    2013-07-02

    A 7-day mixture toxicity experiment with the terrestrial springtail Folsomia candida was conducted, and the effects were linked to three different mixture exposure parameters. Passive dosing from silicone was applied to tightly control exposure levels and compositions of 12 mixture treatments, containing the polycyclic aromatic hydrocarbons (PAHs) naphthalene, phenanthrene, and pyrene. Springtail lethality was then linked to sum chemical activities (∑a), sum equilibrium lipid concentrations (∑C(lipid eq.)), and sum toxic units (∑TU). In each case, the effects of all 12 mixture treatments could be fitted to one sigmoidal exposure-response relationship. The effective lethal chemical activity (La50) of 0.027 was well within the expected range for baseline toxicity of 0.01-0.1. Linking the effects to the lipid-based exposure parameter yielded an effective lethal concentration (LC(lipid eq 50)) of 133 mmol kg(-1) lipid in good correspondence with the lethal membrane burden for baseline toxicity (40-160 mmol kg(-1) lipid). Finally, the effective lethal toxic unit (LTU50) of 1.20 was rather close to the expected value of 1. Altogether, passive dosing provided tightly controlled mixture exposure in terms of both level and composition, while ∑a, ∑C(lipid eq.), and ∑TU allowed baseline toxicity to be linked to mixture exposure.

  2. Effect of two hydrocarbon and one fluorocarbon surfactant mixtures on the surface tension and wettability of polymers.

    PubMed

    Szymczyk, Katarzyna; González-Martín, Maria Luisa; Bruque, Jose Morales; Jańczuk, Bronisław

    2014-03-01

    The advancing contact angle of water, formamide and diiodomethane on polytetrafluoroethylene (PTFE) and polymethyl methacrylate (PMMA) surfaces covered with the film of ternary mixtures of surfactants including p-(1,1,3,3-tetramethylbutyl) phenoxypoly(ethyleneglycols), Triton X-100 (TX100) and Triton X-165 (TX165) and the fluorocarbon surfactants, Zonyl FSN-100 (FSN100) or Zonyl FSO-100 (FSO100) was measured. The obtained results were used for the surface tension of PTFE and PMMA covered with this film determination from the Young equation on the basis of van Oss et al. and Neumann et al. approaches to the interfacial tension. The surface tension of PTFE and PMMA was also determined using the Neumann et al. equation and the contact angle values for the aqueous solutions of the above mentioned ternary surfactants mixtures which were taken from the literature. As follows from our calculations mainly the presence of the fluorocarbon surfactant in the mixture considerably changes the surface properties of PTFE and PMMA causing that in contrast to hydrocarbon surfactants and their mixtures there is no linear dependence between adhesion and surface tension in the whole range of concentration of the ternary mixtures of surfactants including the fluorocarbon one. The behavior of fluorocarbon surfactants at the polymer-air and polymer-water interfaces is quite different from those of hydrocarbons. In the case of fluorocarbon surfactants not only adsorption but also sorption can occur on the polymer surface.

  3. Improved Oral Bioavailability Using a Solid Self-Microemulsifying Drug Delivery System Containing a Multicomponent Mixture Extracted from Salvia miltiorrhiza.

    PubMed

    Bi, Xiaolin; Liu, Xuan; Di, Liuqing; Zu, Qiang

    2016-04-08

    The active ingredients of salvia (dried root of Salvia miltiorrhiza) include both lipophilic (e.g., tanshinone IIA, tanshinone I, cryptotanshinone and dihydrotanshinone I) and hydrophilic (e.g., danshensu and salvianolic acid B) constituents. The low oral bioavailability of these constituents may limit their efficacy. A solid self-microemulsifying drug delivery system (S-SMEDDS) was developed to load the various active constituents of salvia into a single drug delivery system and improve their oral bioavailability. A prototype SMEDDS was designed using solubility studies and phase diagram construction, and characterized by self-emulsification performance, stability, morphology, droplet size, polydispersity index and zeta potential. Furthermore, the S-SMEDDS was prepared by dispersing liquid SMEDDS containing liposoluble extract into a solution containing aqueous extract and hydrophilic polymer, and then freeze-drying. In vitro release of tanshinone IIA, salvianolic acid B, cryptotanshinone and danshensu from the S-SMEDDS was examined, showing approximately 60%-80% of each active component was released from the S-SMEDDS in vitro within 20 min. In vivo bioavailability of these four constituents indicated that the S-SMEDDS showed superior in vivo oral absorption to a drug suspension after oral administration in rats. It can be concluded that the novel S-SMEDDS developed in this study increased the dissolution rate and improved the oral bioavailability of both lipophilic and hydrophilic constituents of salvia. Thus, the S-SMEDDS can be regarded as a promising new method by which to deliver salvia extract, and potentially other multicomponent drugs, by the oral route.

  4. Changes in Brain Monoamines Underlie Behavioural Disruptions after Zebrafish Diet Exposure to Polycyclic Aromatic Hydrocarbons Environmental Mixtures

    PubMed Central

    Vignet, Caroline; Trenkel, Verena M.; Vouillarmet, Annick; Bricca, Giampiero; Bégout, Marie-Laure; Cousin, Xavier

    2017-01-01

    Zebrafish were exposed through diet to two environmentally relevant polycyclic aromatic hydrocarbons (PAHs) mixtures of contrasted compositions, one of pyrolytic (PY) origin and one from light crude oil (LO). Monoamine concentrations were quantified in the brains of the fish after six month of exposure. A significant decrease in noradrenaline (NA) was observed in fish exposed to both mixtures, while a decrease in serotonin (5HT) and dopamine (DA) was observed only in LO-exposed fish. A decrease in metabolites of 5HT and DA was observed in fish exposed to both mixtures. Several behavioural disruptions were observed that depended on mixtures, and parallels were made with changes in monoamine concentrations. Indeed, we observed an increase in anxiety in fish exposed to both mixtures, which could be related to the decrease in 5HT and/or NA, while disruptions of daily activity rhythms were observed in LO fish, which could be related to the decrease in DA. Taken together, these results showed that (i) chronic exposures to PAHs mixtures disrupted brain monoamine contents, which could underlie behavioural disruptions, and that (ii) the biological responses depended on mixture compositions. PMID:28273853

  5. Changes in Brain Monoamines Underlie Behavioural Disruptions after Zebrafish Diet Exposure to Polycyclic Aromatic Hydrocarbons Environmental Mixtures.

    PubMed

    Vignet, Caroline; Trenkel, Verena M; Vouillarmet, Annick; Bricca, Giampiero; Bégout, Marie-Laure; Cousin, Xavier

    2017-03-04

    Zebrafish were exposed through diet to two environmentally relevant polycyclic aromatic hydrocarbons (PAHs) mixtures of contrasted compositions, one of pyrolytic (PY) origin and one from light crude oil (LO). Monoamine concentrations were quantified in the brains of the fish after six month of exposure. A significant decrease in noradrenaline (NA) was observed in fish exposed to both mixtures, while a decrease in serotonin (5HT) and dopamine (DA) was observed only in LO-exposed fish. A decrease in metabolites of 5HT and DA was observed in fish exposed to both mixtures. Several behavioural disruptions were observed that depended on mixtures, and parallels were made with changes in monoamine concentrations. Indeed, we observed an increase in anxiety in fish exposed to both mixtures, which could be related to the decrease in 5HT and/or NA, while disruptions of daily activity rhythms were observed in LO fish, which could be related to the decrease in DA. Taken together, these results showed that (i) chronic exposures to PAHs mixtures disrupted brain monoamine contents, which could underlie behavioural disruptions, and that (ii) the biological responses depended on mixture compositions.

  6. Exploring hydrocarbon-bearing shale formations with multi-component seismic technology and evaluating direct shear modes produced by vertical-force sources

    NASA Astrophysics Data System (ADS)

    Alkan, Engin

    It is essential to understand natural fracture systems embedded in shale-gas reservoirs and the stress fields that influence how induced fractures form in targeted shale units. Multicomponent seismic technology and elastic seismic stratigraphy allow geologic formations to be better images through analysis of different S-wave modes as well as the P-wave mode. Significant amounts of energy produced by P-wave sources radiate through the Earth as downgoing SV-wave energy. A vertical-force source is an effective source for direct SV radiation and provides a pure shear-wave mode (SV-SV) that should reveal crucial information about geologic surfaces located in anisotropic media. SV-SV shear wave modes should carry important information about petrophysical characteristics of hydrocarbon systems that cannot be obtained using other elastic-wave modes. Regardless of the difficulties of extracting good-quality SV-SV signal, direct shear waves as well as direct P and converted S energy should be accounted for in 3C seismic studies. Acquisition of full-azimuth seismic data and sampling data at small intervals over long offsets are required for detailed anisotropy analysis. If 3C3D data can be acquired with improved signal-to-noise ratio, more uniform illumination of targets, increased lateral resolution, more accurate amplitude attributes, and better multiple attenuation, such data will have strong interest by the industry. The objectives of this research are: (1) determine the feasibility of extracting direct SV-SV common-mid-point sections from 3-C seismic surveys, (2) improve the exploration for stratigraphic traps by developing systematic relationship between petrophysical properties and combinations of P and S wave modes, (3) create compelling examples illustrating how hydrocarbon-bearing reservoirs in low-permeable rocks (particularly anisotropic shale formations) can be better characterized using different Swave modes (P-SV, SV-SV) in addition to the conventional P

  7. Investigation of simultaneous biosorption of copper(II) and chromium(VI) on dried Chlorella vulgaris from binary metal mixtures: Application of multicomponent adsorption isotherms

    SciTech Connect

    Aksu, Z.; Acikel, U.; Kutsal, T.

    1999-02-01

    Although the biosorption of single metal ions to various kinds of microorganisms has been extensively studied and the adsorption isotherms have been developed for only the single metal ion situation, very little attention has been given to the bioremoval and expression of adsorption isotherms of multimetal ions systems. In this study the simultaneous biosorption of copper(II) and chromium(VI) to Chlorella vulgaris from a binary metal mixture was studied and compared with the single metal ion situation in a batch stirred system. The effects of pH and single- and dual-metal ion concentrations on the equilibrium uptakes were investigated. In previous studies the optimum biosorption pH had been determined as 4.0 for copper(II) and as 2.0 for chromium(VI). Multimetal ion biosorption studies were performed at these two pH values. It was observed that the equilibrium uptakes of copper(II) or chromium(VI) ions were changed due to the biosorption pH and the presence of other metal ions. Adsorption isotherms were developed for both single- and dual-metal ions systems at these two pH values, and expressed by the mono- and multicomponent Langmuir and Freundlich adsorption models. Model parameters were estimated by nonlinear regression. It was seen that the adsorption equilibrium data fitted very well to the competitive Freundlich model in the concentration ranges studied.

  8. Study of absorption spectra of gasolines and other hydrocarbon mixtures in the second overtone region of the CH3, CH2, CH groups

    NASA Astrophysics Data System (ADS)

    Muradov, V. G.; Sannikov, D. G.

    2007-03-01

    We have obtained experimental and model absorption spectra for individual hydrocarbons (toluene, benzene, n-heptane, and iso-octane) and their mixtures in the near IR range (λ = 1080 1220 nm). We model the spectra of nonsynthetic gasolines obtained under the same conditions by combining the spectra of three pure hydrocarbons. We show that the octane number of the studied gasoline is linearly related to the toluene (or benzene) concentrations in the model mixture.

  9. Acute photo-induced toxicity and toxicokinetics of single compounds and mixtures of polycyclic aromatic hydrocarbons in zebrafish.

    PubMed

    Willis, Alison M; Oris, James T

    2014-09-01

    The present study examined photo-induced toxicity and toxicokinetics for acute exposure to selected polycyclic aromatic hydrocarbons (PAHs) in zebrafish. Photo-enhanced toxicity from co-exposure to ultraviolet (UV) radiation and PAHs enhanced the toxicity and exhibited toxic effects at PAH concentrations orders of magnitude below effects observed in the absence of UV. Because environmental exposure to PAHs is usually in the form of complex mixtures, the present study examined the photo-induced toxicity of both single compounds and mixtures of PAHs. In a sensitive larval life stage of zebrafish, acute photo-induced median lethal concentrations (LC50s) were derived for 4 PAHs (anthracene, pyrene, carbazole, and phenanthrene) to examine the hypothesis that phototoxic (anthracene and pyrene) and nonphototoxic (carbazole and phenanthrene) pathways of mixtures could be predicted from single exposures. Anthracene and pyrene were phototoxic as predicted; however, carbazole exhibited moderate photo-induced toxicity and phenanthrene exhibited weak photo-induced toxicity. The toxicity of each chemical alone was used to compare the toxicity of mixtures in binary, tertiary, and quaternary combinations of these PAHs, and a predictive model for environmental mixtures was generated. The results indicated that the acute toxicity of PAH mixtures was additive in phototoxic scenarios, regardless of the magnitude of photo-enhancement. Based on PAH concentrations found in water and circumstances of high UV dose to aquatic systems, there exists potential risk of photo-induced toxicity to aquatic organisms.

  10. Method for locating the vapor-liquid critical point of multicomponent fluid mixtures using a shear mode piezoelectric sensor.

    PubMed

    Ke, Jie; King, P J; George, Michael W; Poliakoff, Martyn

    2005-01-01

    A new approach to locating the critical point of fluid mixtures is reported, utilizing a shear mode piezoelectric sensor. This technique employs a single piece of quartz crystal that is installed at the bottom of a strongly stirred high-pressure vessel. The sensor response indicates whether liquid or gas is in contact with its surfaces. Thus, the sensor is able to identify vapor-liquid phase separation by registering a discontinuity in the impedance minimum of the sensor as a function of pressure. Two systems (methanol + CO2 and H2 + CO2) have been investigated using this method. The critical point data of the methanol + CO2 system were chosen to validate the approach against a wealth of literature data, and good agreement was obtained. The sensor behavior in the two-phase region, as well as the effect of stirring, is discussed. The method is general and can be used with other sensors.

  11. "Zahraa", a Unani multicomponent herbal tea widely consumed in Syria: components of drug mixtures and alleged medicinal properties.

    PubMed

    Carmona, M D; Llorach, R; Obon, C; Rivera, D

    2005-12-01

    In Unani system of medicine, drugs consist of complex formulae with more than three components, for which, literature analysing these mixtures as they are sold in the market is scarce. In this paper, the main botanical components of the herbal tea known as "Zahraa" in Damascus, which contains between 6 and 14 species components is elucidated: Alcea damascena (Mout.) Mout. (Malvaceae), Aloysia triphylla (L'Herit.) Britt. (Malvaceae), Astragalus cf. amalecitanus Boiss., Cercis siliquastrum L. subsp. hebecarpa (Bornm.) Yalt. and subsp. siliquastrum. (Leguminosae), Colutea cilicica Boiss. et Bal. in Boiss. (Leguminosae), Crataegus aronia (L.) Bosc. ex DC. (Rosaceae), Cytisopsis pseudocytisus (Boiss.) Fertig. (Leguminosae), Eleagnus angustifolia L. (Eleagnaceae), Equisetum telmateia Ehrh. (Equisetaceae), Helichrysum stoechas (L.) Moench. subsp. barrelieri (Ten.) Nyman. (Compositae), Matricaria recutita L. (Compositae), Mentha longifolia L. subsp. noeana (Boiss. ex. Briq.) Briq. (Labiatae), Mentha spicata L. subsp. condensata (Briq.) Greuter and Burdet (Labiatae), Micromeria myrtifolia Boiss. and Hohen. in Boiss. (Labiatae), Paronychia argentea Lam. (Caryophyllaceae), Phlomis syriaca Boiss. (Labiatae), Rosa damascena Mill. (Rosaceae), Salvia fruticosa Mill. (Labiatae), Sambucus nigra L. (Caprifoliaceae), Spartium junceum L. (Leguminosae), Zea mays L. (Gramineae).

  12. Chemical induction of tumors in oysters by a mixture of aromatic and chlorinated hydrocarbons, amines and metals

    SciTech Connect

    Gardner, G.R.; Pruell, R.J.; Malcolm, A.R.

    1992-01-01

    Tumors were induced in eastern oysters (Crassostrea virginica) by a mixture of aromatic hydrocarbons, an aromatic amine, polychlorinated biphenyls, chlorinated hydrocarbons, a nitrosoamine and heavy metals. Kidney and enteric tumors developed in oysters following exposure to a mixture containing 3,4-benzopyrene, 1,2-benzanthracene, 2-aminofluorene, N-nitrosodiethylamine, technical chlordane, Aroclors 1242 and 1254, p,p'-DDE, cadmium (CdCl2), chromium (K2CrO4) and lead (Pb(NO3)2). 2-Aminofluorene and N-nitrosodiethylamine, not measured in Black Rock Harbor sediment, were both added at 0.6 and 6.0 micrograms/g dry sediment. A 3% prevalence of low-grade renal and gastrointestinal tumors developed after 30 days in oysters fed water-column suspended sediment particulate spiked with the mixture of chemicals. Disease progression was most advanced in enteric adenomas. Both types are comparable to those produced after 30 days in the same organs by chemically contaminated Black Rock Harbor sediment.

  13. Effects of Polycyclic Aromatic Hydrocarbon Mixtures on Degradation, Gene Expression, and Metabolite Production in Four Mycobacterium Species

    PubMed Central

    Hennessee, Christiane T.

    2016-01-01

    ABSTRACT Polycyclic aromatic hydrocarbons (PAHs) are widespread environmental contaminants that are hazardous to human health. It has been demonstrated that members of the Mycobacterium genus are among the most effective degraders of PAHs, but few studies have focused on the degradation of PAH mixtures. In this study, single and mixed PAH metabolism was investigated in four phylogenetically distinct Mycobacterium species with respect to (i) parent compound degradation, (ii) bacterial growth, (iii) catabolic gene expression, and (iv) metabolite production. Synergistic and antagonistic effects on four model PAH compounds (benzo[a]pyrene, pyrene, fluoranthene, and phenanthrene) characterized degradation of mixtures in a strain- and mixture-dependent manner. The mixture of pyrene and phenanthrene, in particular, resulted in antagonized degradation by three out of four bacterial species, and further studies were narrowed to investigate the degradation of this mixture. Antagonistic effects persisted over time and were correlated with reduced bacterial growth. Antagonized degradation of PAH was not caused by preferential degradation of secondary PAHs, nor were mixture compounds or concentrations toxic to cells growing on sugars. Reverse transcription-PCR (RT-PCR) studies of the characterized catabolic pathway of phenanthrene showed that in one organism, antagonism of mixture degradation was associated with downregulated gene expression. Metabolite profiling revealed that antagonism in mixture degradation was associated with the shunting of substrate through alternative pathways not used during the degradation of single PAHs. The results of this study demonstrate metabolic differences between single and mixed PAH degradation with consequences for risk assessment and bioremediation of PAH-contaminated sites. IMPORTANCE Mycobacterium species are promising organisms for environmental bioremediation because of their ubiquitous presence in soils and their ability to catabolize

  14. PHOTOACTIVATION AND TOXICITY OF MIXTURES OF POLYCYCLIC AROMATIC HYDROCARBON COMPOUNDS IN MARINE SEDIMENT

    EPA Science Inventory

    The direct toxicity and photoinduced toxicity of sediment-associated acenaphthene, phenanthrene, fluoranthene, and pyrene were determined for the marine amphipod Rhepoxynius abronius. The four polycyclic aromatic hydrocarbons (PAHs) were spiked into sediment in a concentration se...

  15. Interactions between polycyclic aromatic hydrocarbons in complex mixtures and implications for cancer risk assessment.

    PubMed

    Jarvis, Ian W H; Dreij, Kristian; Mattsson, Åse; Jernström, Bengt; Stenius, Ulla

    2014-07-03

    In this review we discuss the effects of exposure to complex PAH mixtures in vitro and in vivo on mechanisms related to carcinogenesis. Of particular concern regarding exposure to complex PAH mixtures is how interactions between different constituents can affect the carcinogenic response and how these might be included in risk assessment. Overall the findings suggest that the responses resulting from exposure to complex PAH mixtures is varied and complicated. More- and less-than additive effects on bioactivation and DNA damage formation have been observed depending on the various mixtures studied, and equally dependent on the different test systems that are used. Furthermore, the findings show that the commonly used biological end-point of DNA damage formation is insufficient for studying mixture effects. At present the assessment of the risk of exposure to complex PAH mixtures involves comparison to individual compounds using either a surrogate or a component-based potency approach. We discuss how future risk assessment strategies for complex PAH mixtures should be based around whole mixture assessment in order to account for interaction effects. Inherent to this is the need to incorporate different experimental approaches using robust and sensitive biological endpoints. Furthermore, the emphasis on future research should be placed on studying real life mixtures that better represent the complex PAH mixtures that humans are exposed to.

  16. Chlorophyll fluorescence as a bioindicator of effects on growth in aquatic macrophytes from mixtures of polycyclic aromatic hydrocarbons.

    PubMed

    Marwood, C A; Solomon, K R; Greenberg, B M

    2001-04-01

    Chlorophyll-a fluorescence induction is a rapid technique for measuring photosynthetic electron transport in plants. To assess chlorophyll-a fluorescence as a bioindicator of effects of polycyclic aromatic hydrocarbon mixtures, chlorophyll-a fluorescence parameters and plant growth responses to exposure to the wood preservative creosote were examined in the aquatic plants Lemna gibba and Myriophyllum spicatum. Exposure to creosote inhibited growth of L. gibba (EC50 = 7.2 mg/L total polycyclic aromatic hydrocarbons) and M. spicatum (EC50 = 2.6 mg/L) despite differences in physiology. Creosote also diminished maximum PSII efficiency (Fv/Fm) (EC50 = 36 and 13 mg/L for L. gibba and M. spicatum) and the effective yield of photosystem II photochemistry (deltaF/Fm') (EC50 = 13 and 15 mg/L for L. gibba and M. spicatum). The similarity between growth and chlorophyll-a fluorescence EC50s and slopes of the response curves suggests a close mechanistic link between these end points. The predictive power of chlorophyll-a fluorescence as a bioindicator of whole-organism effects applied to complex contaminant mixtures is discussed.

  17. An In Silico Approach for Evaluating a Fraction-Based, Risk Assessment Method for Total Petroleum Hydrocarbon Mixtures

    PubMed Central

    Wang, Nina Ching Y.; Rice, Glenn E.; Teuschler, Linda K.; Colman, Joan; Yang, Raymond S. H.

    2012-01-01

    Both the Massachusetts Department of Environmental Protection (MADEP) and the Total Petroleum Hydrocarbon Criteria Working Group (TPHCWG) developed fraction-based approaches for assessing human health risks posed by total petroleum hydrocarbon (TPH) mixtures in the environment. Both organizations defined TPH fractions based on their expected environmental fate and by analytical chemical methods. They derived toxicity values for selected compounds within each fraction and used these as surrogates to assess hazard or risk of exposure to the whole fractions. Membership in a TPH fraction is generally defined by the number of carbon atoms in a compound and by a compound's equivalent carbon (EC) number index, which can predict its environmental fate. Here, we systematically and objectively re-evaluate the assignment of TPH to specific fractions using comparative molecular field analysis and hierarchical clustering. The approach is transparent and reproducible, reducing inherent reliance on judgment when toxicity information is limited. Our evaluation of membership in these fractions is highly consistent (˜80% on average across various fractions) with the empirical approach of MADEP and TPHCWG. Furthermore, the results support the general methodology of mixture risk assessment to assess both cancer and noncancer risk values after the application of fractionation. PMID:22496687

  18. Does equilibrium passive sampling reflect actual in situ bioaccumulation of PAHs and petroleum hydrocarbon mixtures in aquatic worms?

    PubMed

    Muijs, Barry; Jonker, Michiel T O

    2012-01-17

    Over the past couple of years, several analytical methods have been developed for assessing the bioavailability of environmental contaminants in sediments and soils. Comparison studies suggest that equilibrium passive sampling methods generally provide the better estimates of internal concentrations in organisms and thus of subsequent risks. However, field studies to validate the potential of passive sampling to predict actual in situ bioaccumulation are scarce and limited information only exists on selected, individual compounds. The present study investigated whether bioaccumulation of PAH and complex petroleum hydrocarbon mixtures in field-exposed aquatic worms could be predicted properly with passive samplers. To this end, in situ bioaccumulation in aquatic worms at 6 PAH-contaminated locations and 8 petroleum hydrocarbon (oil)-contaminated locations was compared with the results of in situ solid phase micro extraction (SPME) applications. For the oil-contaminated sediments, bioaccumulation was also assessed in the lab with polyoxymethylene solid phase extraction (POM-SPE). Actual PAH bioaccumulation was generally predicted within a factor of 4 with in situ SPME, using temperature-adjusted SPME fiber-water partition coefficients and lab-derived bioaccumulation factors (BAFs) for the worm species used, demonstrating the method's potential under field conditions. In situ SPME appeared to be less suitable for predicting bioaccumulation of oil however, in contrast to POM-SPE in the lab, which assessed in situ oil bioaccumulation within a factor of 3, while also closely reflecting the actual distribution of oil boiling point fractions (the hydrocarbon block profile) as accumulated by the worms. All in all, the results indicated that (specific) equilibrium passive samplers, either applied in the field or the lab, have great potential for assessing bioaccumulation of environmental contaminant mixtures from field-contaminated sediments.

  19. Biodegradation kinetics and bioreactor strategy for aromatic hydrocarbon and trichloroethylene mixtures

    SciTech Connect

    Reardon, K.F.; Conuel, J.R.; Mosteller, D.C.

    1994-12-31

    Although most contaminated sites contain a mixture of pollutants, little is known about the biodegradation of mixtures. Highlights of two investigations into mixture biodegradation are reported here. In the first, the kinetics of biodegradation of benzene, toluene and phenol by Pseudomonas putida F1 were measured in suspended-cell, batch cultivations, both individually and as mixtures. Significant substrate interactions were observed. A mathematical model that incorporates an interaction coefficient was applied to the data and was found to predict the kinetics well. In the second example, an immobilized-cell bioreactor for the cometabolic removal of trichloroethylene was developed. Pulsed feeding of the growth substrate, toluene, was found to remove trichloroethylene at a rate 35% higher than the removal rate with constant toluene feeding.

  20. Improved Separation of Complex Polycyclic Aromatic Hydrocarbon Mixtures Using Novel Column Combinations in GC×GC/ToF-MS

    PubMed Central

    Manzano, Carlos; Hoh, Eunha; Simonich, Staci L. Massey

    2012-01-01

    Complex mixtures of polycyclic aromatic hydrocarbons (PAHs) are difficult to resolve because of the high degree of overlap in compound vapor pressures, boiling points and mass spectral fragmentation patterns. The objective of this research was to improve the separation of complex PAH mixtures (including 97 different parent, alkyl-, nitro-, oxy-, thio-, chloro-, bromo-, and high molecular weight PAHs) using GC×GC/ToF-MS by maximizing the orthogonality of different GC column combinations and improving the separation of PAHs from the sample matrix interferences, including unresolved complex mixtures (UCM). Four different combinations of non-polar, polar, liquid crystal and nano-stationary phase columns were tested. Each column combination was optimized and evaluated for orthogonality using a method based on conditional entropy that considers the quantitative peak distribution in the entire two-dimensional space. Finally, an atmospheric particulate matter with diameter < 2.5 µm (PM2.5) sample from Beijing, China, a soil sample from St. Maries Creosote Superfund Site, and a sediment sample from the Portland Harbor Superfund Site were analyzed for complex mixtures of PAHs. The highest chromatographic resolution, lowest synentropy, highest orthogonality and lowest interference from UCM were achieved using a 10 m × 0.15 mm × 0.10 µm LC-50 liquid crystal column in the first dimension and a 1.2 m × 0.10 mm × 0.10 µm NSP-35 nano-stationary phase column in the second dimension. In addition, the use of this column combination in GC×GC/ToF-MS resulted in significantly shorter analysis times (176 min) for complex PAH mixtures compared to one-dimensional GC/MS (257 min), as well as potentially reduced sample preparation time. PMID:22769970

  1. Bioremediation of a soil contaminated by hydrocarbon mixtures: the residual concentration problem.

    PubMed

    Nocentini, M; Pinelli, D; Fava, F

    2000-10-01

    The phenomenon of residual concentration was investigated in the aerobic biodegradation of three different petroleum commercial products (i.e., kerosene, diesel fuel and a lubricating mineral oil) in static microcosms. Two different soils exhibiting different physical-chemical characteristics were used (i.e., a biologically treated hydrocarbon-contaminated soil and a pristine soil). Residual concentrations were observed and a simple way to take this phenomenon into account was proposed.

  2. Improved resolution of hydrocarbon structures and constitutional isomers in complex mixtures using Gas Chromatography-Vacuum Ultraviolet-Mass Spectrometry (GC-VUV-MS)

    SciTech Connect

    Aerosol Dynamics Inc; Aerodyne Research, Inc.,; Tofwerk AG, Thun; Isaacman, Gabriel; Wilson, Kevin R.; Chan, Arthur W. H.; Worton, David R.; Kimmel, Joel R.; Nah, Theodora; Hohaus, Thorsten; Gonin, Marc; Kroll, Jesse H.; Worsnop, Doug R.; Goldstein, Allen H.

    2011-09-13

    Understanding the composition of complex hydrocarbon mixtures is important for environmental studies in a variety of fields, but many prevalent compounds cannot be confidently identified using traditional gas chromatography-mass spectrometry (GC-MS) techniques. This work uses vacuum-ultraviolet (VUV) ionization to elucidate the structures of a traditionally"unresolved complex mixture" by separating components by GC retention time, tR, and mass-to-charge ratio, m/Q, which are used to determine carbon number, NC, and the number of rings and double bonds, NDBE. Constitutional isomers are resolved based on tR, enabling the most complete quantitative analysis to date of structural isomers in an environmentally-relevant hydrocarbon mixture. Unknown compounds are classified in this work by carbon number, degree of saturation, presence of rings, and degree of branching, providing structural constraints. The capabilities of this analysis are explored using diesel fuel, in which constitutional isomer distribution patterns are shown to be reproducible between carbon numbers and follow predictable rules. Nearly half of the aliphatic hydrocarbon mass is shown to be branched, suggesting branching is more important in diesel fuel than previously shown. The classification of unknown hydrocarbons and the resolution of constitutional isomers significantly improves resolution capabilities for any complex hydrocarbon mixture.

  3. Detailed Kinetic Modeling of Gasoline Surrogate Mixtures

    SciTech Connect

    Mehl, M; Curran, H J; Pitz, W J; Westbrook, C K

    2009-03-09

    Real fuels are complex mixtures of thousands of hydrocarbon compounds including linear and branched paraffins, naphthenes, olefins and aromatics. It is generally agreed that their behavior can be effectively reproduced by simpler fuel surrogates containing a limited number of components. In this work, a recently revised version of the kinetic model by the authors is used to analyze the combustion behavior of several components relevant to gasoline surrogate formulation. Particular attention is devoted to linear and branched saturated hydrocarbons (PRF mixtures), olefins (1-hexene) and aromatics (toluene). Model predictions for pure components, binary mixtures and multi-component gasoline surrogates are compared with recent experimental information collected in rapid compression machine, shock tube and jet stirred reactors covering a wide range of conditions pertinent to internal combustion engines. Simulation results are discussed focusing attention on the mixing effects of the fuel components.

  4. [Mutagenicity of mixtures of halogenated aliphatic hydrocarbons and polycyclic aromatic hydrocarbons in the Ames test with TA98 and TA100].

    PubMed

    Kevekordes, S; Porzig, J; Gebel, T; Dunkelberg, H

    1998-02-01

    Within the framework of the assessment of the genotoxic potential of environment samples the Salmonella-microsome-test (Ames-test) is often used as a screening-test. It is one of the most applied biotest systems and possesses a large scientific acceptance. Because most environment samples are mixtures of various substances, possible effects resulting from the combination should be taken into account with regard to the mutagenic potential. In this context we investigated eight polycyclic aromatic hydrocarbons each combined with six halogenated aliphatic hydrocarbons as to their mutagenicity in the Salmonella-microsome-test with TA98 and TA100. For an exogenous metabolizing system, Arochlor 1254 induced rat liver S9-mix was used. Benz-a-pyrene in combination with bromodichloromethane (Ames neg. in TA98 and TA100 +S9) showed an increase in the number of the revertants up to 25% in TA98 and TA100 (+S9). Carbon tetrachloride (Ames neg. in TA98 and TA100 +S9) showed in TA100 (+S9) an increase in the number of the revertants of 18% at most. In the combination 3-methylcholanthrene with dichloromethane the number of revertants in TA98 (+S9) increased by 25% and in TA100 (+S9) by 18%. Hexachloroethane (weakly mutagenic in TA98 +S9) in combination showed in TA98 (+S9) a slightly increased number of revertants with benz-a-pyrene as well with 3-methylcholanthrene. All the other substances tested (chrysene, phenanthrene, anthanthrene, dibenz-a, i-pyrene, triphenylene, fluoranthene) in combination with either tetrachloroethylene or trichloroethene did not cause an increase in mutagenicity.

  5. Aryl hydrocarbon-induced interactions at multiple DNA elements of diverse sequence--a multicomponent mechanism for activation of cytochrome P4501A1 (CYP1A1) gene transcription.

    PubMed Central

    Robertson, R W; Zhang, L; Pasco, D S; Fagan, J B

    1994-01-01

    In vivo footprinting experiments, augmented with gel shift and transfection analyses suggest that activation of the CYP1A1 gene by aryl hydrocarbons may be a multicomponent process. During the first 30 minutes of exposure to aryl hydrocarbon carcinogens and environmental contaminants, in vivo footprints appear at nine distinct sites within a 281 bp region centered 950 bp upstream of the CYP1A1 transcription start site. Six of these sites are unrelated in sequence to the three xenobiotic response elements (XREs) within this region, at which the aryl hydrocarbon (AH) receptor is known to bind. These six display a variety of footprint patterns, are diverse in sequence and range in G-C content from 60 to 75%. This diversity suggests that multiple nuclear factors may be responsible for these six in vivo footprints. These observations are consistent with competition gel shift experiments showing that the nuclear factors binding at two of these sites are different from each other, as well as from the AH receptor. Gel shifts also indicate that the sequence-specific factors binding at these sites are expressed constitutively. This is consistent with a model in which in vivo footprints are induced at these six sites, not through direct activation or de novo synthesis of DNA-binding factors, but through a two phase mechanism in which binding of the nuclear AH receptor complex to XREs facilitates the binding of constitutive factors at these sites. This facilitation could be mediated either through specific protein-protein interactions or through alterations in chromatin structure that make these sites accessible to constitutive nuclear factors. A function for the sequences at which aryl hydrocarbons induce in vivo footprints is suggested by transfection experiments showing that one of these sequences cooperates with a weak XRE to confer on a reporter gene responsiveness to aryl hydrocarbons. Images PMID:8202380

  6. Liquid-liquid equilibria of binary mixtures of a lipidic ionic liquid with hydrocarbons.

    PubMed

    Green, Blane D; Badini, Alexander J; O'Brien, Richard A; Davis, James H; West, Kevin N

    2016-01-28

    Although structurally diverse, many ionic liquids (ILs) are polar in nature due to the strong coulombic forces inherent in ionic compounds. However, the overall polarity of the IL can be tuned by incorporating significant nonpolar content into one or more of the constituent ions. In this work, the binary liquid-liquid equilibria of one such IL, 1-methyl-3-(Z-octadec-9-enyl)imidazolium bistriflimide, with several hydrocarbons (n-hexane, n-octane, n-decane, cyclohexane, methylcyclohexane, 1-octene) is measured over the temperature range 0-70 °C at ambient pressure using a combination of cloud point and gravimetric techniques. The phase behavior of the systems are similar in that they exhibit two phases: one that is 60-90 mole% hydrocarbon and a second phase that is nearly pure hydrocarbon. Each phase exhibits a weak dependence of composition on temperature (steep curve) above ∼10 °C, likely due to swelling and restructuring of the nonpolar nano-domains of the IL being limited by energetically unfavorable restructuring in the polar nano-domains. The solubility of the n-alkanes decreases with increasing size (molar volume), a trend that continues for the cyclic alkanes, for which upper critical solution temperatures are observed below 70 °C. 1-Octene is found to be more soluble than n-octane, attributable to a combination of its lower molar volume and slightly higher polarity. The COSMO-RS model is used to predict the T-x'-x'' diagrams and gives good qualitative agreement of the observed trends. This work presents the highest known solubility of n-alkanes in an IL to date and tuning the structure of the ionic liquid to maximize the size/shape trends observed may provide the basis for enhanced separations of nonpolar species.

  7. Physical gelation of binary mixtures of hydrocarbons mediated by n-lauroyl-L-alanine and characterization of their thermal and mechanical properties.

    PubMed

    Bhattacharya, Santanu; Pal, Asish

    2008-04-24

    Fatty acid amides, such as n-lauroyl-L-alanine, gelate both aliphatic and aromatic hydrocarbon solvents efficiently. In addition this compound is found to gelate the binary solvent mixtures comprised of aromatic hydrocarbon, e.g., toluene and aliphatic hydrocarbons, e.g., n-heptane. Scanning electron microscopy and atomic force microscopy show that the fiber thickness of the gel assembly increases progressively in the binary mixture of n-heptane and toluene with increasing percentage of toluene. The self-assembly patterns of the gels in individual solvents, n-heptane and toluene, are however different. The toluene gel consists of predominantly one type of morphological species, while n-heptane gel has more than one species leading to the polymorphic nature of the gel. The n-heptane gel is thermally more stable than the toluene gel as evident from the measurement using differential scanning calorimetry. The thermal stability of the gels prepared in the binary mixture of n-heptane and toluene is dependent on the composition of solvent mixture. Rheology of the gels shows that they are shear-thinning material and show characteristic behavior of soft viscoelastic solid. For the gels prepared from binary solvent mixture of toluene and n-heptane, with incorporation of more toluene in the binary mixture, the gel becomes a more viscoelastic solid. The time sweep rheology experiment demonstrates that the gel made in n-heptane has faster gel formation kinetics than that prepared in toluene.

  8. Extraction of aromatic hydrocarbons by mixtures of diethylene glycol with N-formylmorpholine

    SciTech Connect

    Marusina, N.B.; Gaile, A.A.; Semenov, L.V.

    1995-12-20

    The authors studied physiochemical properties of mixtures of diethylene glycol with N-formylmorpholine and water and liquid-liquid phase equilibria in the systems heptane-toulene-mixed extractant (diethylene glycol N-formylmorpholine-water in a weight ratio of 66.5:28.5:5.0) at 100{degrees}C. The authors studied also the system consisting of the 62-105{degrees}C fraction of reforming naphtha and the same extractant at 70 and 100{degrees}C.

  9. A closer look at bioaccumulation of petroleum hydrocarbon mixtures in aquatic worms.

    PubMed

    Muijs, Barry; Jonker, Michiel T O

    2010-09-01

    Petroleum hydrocarbons (oils) are ubiquitous in the aquatic environment, and adequate risk assessment is thus essential. Bioaccumulation plays a key role in risk assessment, but the current knowledge on bioaccumulation of oils is limited. Therefore, this process was studied in detail, using the aquatic worm, Lumbriculus variegatus, and 14 field-contaminated sediments. The main focus during the present study was on uptake kinetics, the relationship between oil boiling point fraction and uptake, and effects of sediment characteristics. Uptake kinetics became slower with increasing boiling point fraction, but 70 to 90% of the equilibrium situation was reached within the standard exposure duration of 28 d. Worms accumulated sedimentary petroleum hydrocarbons in the range of C(10) to C(34), a range much wider than expected. Biota-to-sediment accumulation factors (BSAFs) for separate boiling point fractions were constant and around the proposed value of 1 to 2 up to C(22), but gradually decreased beyond this point. The decrease was probably caused by a combination of nonequilibrium conditions and enhanced sorption of higher boiling point fractions to sediments; the latter possibly due to the presence of strongly sorbing separate oil phases or black carbon. A negative relationship was observed between BSAF and oil concentration in sediment, which was explained by the presence of separate oil phases at high oil concentrations. These strongly sorbing phases may limit their own availability, particularly when being highly weathered; worms may also avoid them. The observed phenomena have obvious implications for bioaccumulation assessment of oils and suggest that the current risk assessment procedure for oils in sediments may lead to erroneous results.

  10. CRYSTALLIZATION IN MULTICOMPONENT GLASSES

    SciTech Connect

    KRUGER AA; HRMA PR

    2009-10-08

    In glass processing situations involving glass crystallization, various crystalline forms nucleate, grow, and dissolve, typically in a nonuniform temperature field of molten glass subjected to convection. Nuclear waste glasses are remarkable examples of multicomponent vitrified mixtures involving partial crystallization. In the glass melter, crystals form and dissolve during batch-to-glass conversion, melter processing, and product cooling. Crystals often agglomerate and sink, and they may settle at the melter bottom. Within the body of cooling glass, multiple phases crystallize in a non-uniform time-dependent temperature field. Self-organizing periodic distribution (the Liesegnang effect) is common. Various crystallization phenomena that occur in glass making are reviewed.

  11. Magnetization of multicomponent ferrofluids.

    PubMed

    Szalai, I; Dietrich, S

    2011-08-17

    The solution of the mean spherical approximation (MSA) integral equation for isotropic multicomponent dipolar hard sphere fluids without external fields is used to construct a density functional theory (DFT), which includes external fields, in order to obtain an analytical expression for the external field dependence of the magnetization of ferrofluidic mixtures. This DFT is based on a second-order Taylor series expansion of the free energy density functional of the anisotropic system around the corresponding isotropic MSA reference system. The ensuing results for the magnetic properties are in quantitative agreement with our canonical ensemble Monte Carlo simulation data presented here.

  12. Composition of Soil Microbial Communities Enriched on a Mixture of Aromatic Hydrocarbons

    PubMed Central

    Greene, E. Anne; Kay, Jason G.; Jaber, Karim; Stehmeier, Les G.; Voordouw, Gerrit

    2000-01-01

    Soil contaminated with C5+, which contained benzene (45%, wt/wt), dicyclopentadiene (DCPD) plus cyclopentadiene (together 20%), toluene (6%), styrene (3%), xylenes (2%), naphthalene (2%), and smaller quantities of other compounds, served as the source for isolation of 55 genomically distinct bacteria (standards). Use of benzene as a substrate by these bacteria was most widespread (31 of 44 standards tested), followed by toluene (23 of 44), xylenes (14 of 44), styrene (10 of 44), and naphthalene (10 of 44). Master filters containing denatured genomic DNAs of all 55 standards were used to analyze the community compositions of C5+ enrichment cultures by reverse sample genome probing (RSGP). The communities enriched from three contaminated soils were similar to those enriched from three uncontaminated soils from the same site. The compositions of these communities were time dependent and showed a succession of Pseudomonas and Rhodococcus spp. before convergence on a composition dominated by Alcaligenes spp. The dominant community members detected by RSGP were capable of benzene degradation at all stages of succession. The enrichments effectively degraded all C5+ components except DCPD. Overall, degradation of individual C5+ hydrocarbons followed first-order kinetics, with the highest rates of removal for benzene. PMID:11097903

  13. The suitability of concentration addition for predicting the effects of multi-component mixtures of up to 17 anti-androgens with varied structural features in an in vitro AR antagonist assay

    SciTech Connect

    Ermler, Sibylle; Scholze, Martin; Kortenkamp, Andreas

    2011-12-15

    The risks associated with human exposures to chemicals capable of antagonising the effects of endogenous androgens have attracted considerable recent interest. Exposure is typically to large numbers of chemicals with androgen receptor (AR) antagonist activity, yet there is limited evidence of the combined effects of multi-component mixtures of these chemicals. A few in vitro studies with mixtures of up to six AR antagonists suggest that the concept of concentration addition (CA) provides good approximations of experimentally observed mixture effects, but studies with larger numbers of anti-androgens, and with more varied structural features, are missing. Here we show that the mixture effects of up to 17 AR antagonists, comprising compounds as diverse as UV-filter substances, parabens, perfluorinated compounds, bisphenol-A, benzo({alpha})pyrene, synthetic musks, antioxidants and polybrominated biphenyls, can be predicted well on the basis of the anti-androgenicity of the single components using the concept of CA. We tested these mixtures in an in vitro AR-dependent luciferase reporter gene assay, based on MDA-kb2 cells. The effects of further mixtures, composed of four and six anti-androgens, could be predicted accurately by CA. However, there was a shortfall from expected additivity with a ten-component mixture at two different mixture ratios, but attempts to attribute these deviations to differential expression of hormone-metabolising CYP isoforms did not produce conclusive results. CA provides good approximations of in vitro mixture effects of anti-androgens with varying structural features. -- Highlights: Black-Right-Pointing-Pointer Humans are exposed to a large number of androgen receptor antagonists. Black-Right-Pointing-Pointer There is limited evidence of the combined effects of anti-androgenic chemicals. Black-Right-Pointing-Pointer We modelled the predictability of combined effects of up to 17 anti-androgens. Black-Right-Pointing-Pointer We tested the

  14. Bubble curves and saturated liquid molar volumes for chlorofluorohydrocarbon-hydrocarbon mixtures: Experimental data and modeling

    SciTech Connect

    Laugier, S. ); Richon, D.; Renon, H. . Lab. de Thermodynamique)

    1994-01-01

    Vapor-liquid equilibria and liquid densities were obtained using a static apparatus fitted with a variable-volume cell which was described in detail by Valtz et al. (1). Results are given at four temperatures for the binary systems butane--1,2,2-trichlorotrifluoroethane, pentane--1,2-dichloro-1,1,2,2-tetrafluoroethane, hexane--1,2-dichloro-1,1,2,2-tetrafluoroethane, heptane--1,12-trichloro-1,2,2-trifluoromethane, heptane--1,2-dichloro-1,1,2,2-tetrafluoroethane, and benzene--1,2-dichloro-1,1,2,2-tetrafluoroethane and the ternary system 1,2-dichloro-1,1,2,2-tetrafluoroethane--1,1,2-trichloro-1,2,2-trifluoromethane--heptane. The best simultaneous representation of pressures and saturated liquid molar volumes at a given temperature and liquid composition for these mixtures is obtained using either the Patel-Teja or Trebble-Bishnoi-Salim equation of state (TBS EOS) in either their standard or generalized form (maximum deviation 0.7% in pressure and 3.1% in saturated liquid molar volume with the TBS EOS).

  15. Effect of post injections on mixture preparation and unburned hydrocarbon emissions in a heavy-duty diesel engine

    DOE PAGES

    O'Connor, Jacqueline; Musculus, Mark P. B.; Pickett, Lyle M.

    2016-05-30

    This work explores the mechanisms by which a post injection can reduce unburned hydrocarbon (UHC) emissions in heavy-duty diesel engines operating at low-temperature combustion conditions. Post injections, small, close-coupled injections of fuel after the main injection, have been shown to reduce UHC in the authors’ previous work. In this work, we analyze optical data from laser-induced fluorescence of both CH2O and OH and use chemical reactor modeling to better understand the mechanism by which post injections reduce UHC emissions. The results indicate that post-injection efficacy, or the extent to which a post injection reduces UHC emissions, is a strong functionmore » of the cylinder pressure variation during the post injection. However, the data and analysis indicate that the pressure and temperature rise from the post injection combustion cannot solely explain the UHC reduction measured by both engine-out and optical diagnostics. In conclusion, the fluid-mechanic, thermal, and chemical interaction of the post injection with the main-injection mixture is a key part of UHC reduction; the starting action of the post jet and the subsequent entrainment of surrounding gases are likely both important processes in reducing UHC with a post injection.« less

  16. Effect of post injections on mixture preparation and unburned hydrocarbon emissions in a heavy-duty diesel engine

    SciTech Connect

    O'Connor, Jacqueline; Musculus, Mark P. B.; Pickett, Lyle M.

    2016-05-30

    This work explores the mechanisms by which a post injection can reduce unburned hydrocarbon (UHC) emissions in heavy-duty diesel engines operating at low-temperature combustion conditions. Post injections, small, close-coupled injections of fuel after the main injection, have been shown to reduce UHC in the authors’ previous work. In this work, we analyze optical data from laser-induced fluorescence of both CH2O and OH and use chemical reactor modeling to better understand the mechanism by which post injections reduce UHC emissions. The results indicate that post-injection efficacy, or the extent to which a post injection reduces UHC emissions, is a strong function of the cylinder pressure variation during the post injection. However, the data and analysis indicate that the pressure and temperature rise from the post injection combustion cannot solely explain the UHC reduction measured by both engine-out and optical diagnostics. In conclusion, the fluid-mechanic, thermal, and chemical interaction of the post injection with the main-injection mixture is a key part of UHC reduction; the starting action of the post jet and the subsequent entrainment of surrounding gases are likely both important processes in reducing UHC with a post injection.

  17. Free Energy-Based Coarse-Grained Force Field for Binary Mixtures of Hydrocarbons, Nitrogen, Oxygen, and Carbon Dioxide.

    PubMed

    Cao, Fenglei; Deetz, Joshua D; Sun, Huai

    2017-01-23

    The free energy based Lennard-Jones 12-6 (FE-12-6) coarse-grained (CG) force field developed for alkanes1 has been extended to model small molecules of light hydrocarbons (methane, ethane, propane, butane, and isobutane), nitrogen, oxygen, and carbon dioxide. The adjustable parameters of the FE-12-6 potential are determined by fitting against experimental vapor-liquid equilibrium (VLE) curves and heat of vaporization (HOV) data for pure substance liquids. Simulations using the optimized FE-12-6 parameters correctly reproduced experimental measures of the VLE, HOV, density, vapor pressure, compressibility, critical point, and surface tension for pure substances over a wide range of thermodynamic states. The force field parameters optimized for pure substances were tested on methane/butane, nitrogen/decane, and carbon dioxide/decane binary mixtures to predict their vapor-liquid equilibrium phase diagrams. It is found that for nonpolar molecules represented by different sized beads, a common scaling factor (0.08) that reduces the strength of the interaction potential between unlike beads, generated using Lorentz-Berthelot (LB) combination rules, is required to predict vapor-liquid phase equilibria accurately.

  18. Phase behavior, rheological property, and transmutation of vesicles in fluorocarbon and hydrocarbon surfactant mixtures.

    PubMed

    Yuan, Zaiwu; Qin, Menghua; Chen, Xiushan; Liu, Changcheng; Li, Hongguang; Hao, Jingcheng

    2012-06-26

    We present a detailed study of a salt-free cationic/anionic (catanionic) surfactant system where a strongly alkaline cationic surfactant (tetradecyltrimethylammonium hydroxide, TTAOH) was mixed with a single-chain fluorocarbon acid (nonadecafluorodecanoic acid, NFDA) and a hyperbranched hydrocarbon acid [di-(2-ethylhexyl)phosphoric acid, DEHPA] in water. Typically the concentration of TTAOH is fixed while the total concentration and mixing molar ratio of NFDA and DEHPA is varied. In the absence of DEHPA and at a TTAOH concentration of 80 mmol·L(-1), an isotropic L(1) phase, an L(1)/L(α) two-phase region, and a single L(α) phase were observed successively with increasing mixing molar ratio of NFDA to TTAOH (n(NFDA)/n(TTAOH)). In the NFDA-rich region (n(NFDA)/n(TTAOH) > 1), a small amount of excess NFDA can be solubilized into the L(α) phase while a large excess of NFDA eventually leads to phase separation. When NFDA is replaced gradually by DEHPA, the mixed system of TTAOH/NFDA/DEHPA/H(2)O follows the same phase sequence as that of the TTAOH/NFDA/H(2)O system and the phase boundaries remain almost unchanged. However, the viscoelasticity of the samples in the single L(α) phase region becomes higher at the same total surfactant concentration as characterized by rheological measurements. Cryo-transmission electron microscopic (cryo-TEM) observations revealed a microstructural evolution from unilamellar vesicles to multilamellar ones and finally to gaint onions. The size of the vesicle and number of lamella can be controlled by adjusting the molar ratio of NFDA to DEHPA. The dynamic properties of the vesicular solutions have also been investigated. It is found that the yield stress and the storage modulus are time-dependent after a static mixing process between the two different types of vesicle solutions, indicating the occurrence of a dynamic fusion between the two types of vesicles. The microenvironmental changes induced by aggregate transitions were probed by

  19. Tube radial distribution phenomenon with a two-phase separation solution of a fluorocarbon and hydrocarbon organic solvent mixture in a capillary tube and metal compounds separation.

    PubMed

    Kitaguchi, Koichi; Hanamura, Naoya; Murata, Masaharu; Hashimoto, Masahiko; Tsukagoshi, Kazuhiko

    2014-01-01

    A fluorocarbon and hydrocarbon organic solvent mixture is known as a temperature-induced phase-separation solution. When a mixed solution of tetradecafluorohexane as a fluorocarbon organic solvent and hexane as a hydrocarbon organic solvent (e.g., 71:29 volume ratio) was delivered in a capillary tube that was controlled at 10°C, the tube radial distribution phenomenon (TRDP) of the solvents was clearly observed through fluorescence images of the dye, perylene, dissolved in the mixed solution. The homogeneous mixed solution (single phase) changed to a heterogeneous solution (two phases) with inner tetradecafluorohexane and outer hexane phases in the tube under laminar flow conditions, generating the dynamic liquid-liquid interface. We also tried to apply TRDP to a separation technique for metal compounds. A model analyte mixture, copper(II) and hematin, was separated through the capillary tube, and detected with a chemiluminescence detector in this order within 4 min.

  20. Final report on EURAMET.QM-S6/1195: Bilateral comparison of liquefied hydrocarbon mixtures in constant pressure (piston) cylinders

    NASA Astrophysics Data System (ADS)

    Brown, Andrew S.; Downey, Michael L.; Milton, Martin J. T.; van der Veen, Adriaan M. H.; Zalewska, Ewelina T.; Li, Jianrong

    2013-01-01

    Traceable liquid hydrocarbon mixtures are required in order to underpin measurements of the composition and other physical properties of LPG (liquefied petroleum gas) and LNG (liquefied natural gas), thus meeting the needs of an increasingly large European industrial market. The development of traceable liquid hydrocarbon standards by National Measurement Institutes (NMIs) was still at a relatively early stage at the time this comparison was proposed in 2011. NPL and VSL, who were the only NMIs active in this area, had developed methods for the preparation and analysis of such standards in constant pressure (piston) cylinders, but neither laboratory had Calibration and Measurement Capabilities (CMCs) for these mixtures. This report presents the results of EURAMET 1195, the first comparison of liquid hydrocarbon mixtures between NMIs, which assessed the preparation and analytical capabilities of NPL and VSL for these mixtures. The comparison operated between August 2011 and January 2012. Each laboratory prepared a liquid hydrocarbon standard with nominally the same composition and these standards were exchanged for analysis. The results of the comparison show a good agreement between the laboratories' results and the comparison reference values for the six components with amount fractions greater than 1.0 cmol/mol (propane, propene, iso-butene, n-butane, iso-butane and 1-butene). Measurement of the three components with lower amount fractions (1,3-butadiene, iso-pentane and n-pentane) proved more challenging. In all but one case, the differences from the comparison reference values for these three components were greater than the expanded measurement uncertainty. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by EURAMET, according to the provisions of the CIPM Mutual

  1. The evolution of multicomponent systems at high pressures: VI. The thermodynamic stability of the hydrogen–carbon system: The genesis of hydrocarbons and the origin of petroleum

    PubMed Central

    Kenney, J. F.; Kutcherov, Vladimir A.; Bendeliani, Nikolai A.; Alekseev, Vladimir A.

    2002-01-01

    The spontaneous genesis of hydrocarbons that comprise natural petroleum have been analyzed by chemical thermodynamic-stability theory. The constraints imposed on chemical evolution by the second law of thermodynamics are briefly reviewed, and the effective prohibition of transformation, in the regime of temperatures and pressures characteristic of the near-surface crust of the Earth, of biological molecules into hydrocarbon molecules heavier than methane is recognized. For the theoretical analysis of this phenomenon, a general, first-principles equation of state has been developed by extending scaled particle theory and by using the technique of the factored partition function of the simplified perturbed hard-chain theory. The chemical potentials and the respective thermodynamic Affinity have been calculated for typical components of the H–C system over a range of pressures between 1 and 100 kbar (1 kbar = 100 MPa) and at temperatures consistent with those of the depths of the Earth at such pressures. The theoretical analyses establish that the normal alkanes, the homologous hydrocarbon group of lowest chemical potential, evolve only at pressures greater than ≈30 kbar, excepting only the lightest, methane. The pressure of 30 kbar corresponds to depths of ≈100 km. For experimental verification of the predictions of the theoretical analysis, a special high-pressure apparatus has been designed that permits investigations at pressures to 50 kbar and temperatures to 1,500°C and also allows rapid cooling while maintaining high pressures. The high-pressure genesis of petroleum hydrocarbons has been demonstrated using only the reagents solid iron oxide, FeO, and marble, CaCO3, 99.9% pure and wet with triple-distilled water. PMID:12177438

  2. Chemical kinetic modeling of component mixtures relevant to gasoline

    SciTech Connect

    Mehl, M; Curran, H J; Pitz, W J; Westbrook, C K

    2009-02-13

    Real fuels are complex mixtures of thousands of hydrocarbon compounds including linear and branched paraffins, naphthenes, olefins and aromatics. It is generally agreed that their behavior can be effectively reproduced by simpler fuel surrogates containing a limited number of components. In this work, a recently revised version of the kinetic model by the authors is used to analyze the combustion behavior of several components relevant to gasoline surrogate formulation. Particular attention is devoted to linear and branched saturated hydrocarbons (PRF mixtures), olefins (1-hexene) and aromatics (toluene). Model predictions for pure components, binary mixtures and multi-component gasoline surrogates are compared with recent experimental information collected in rapid compression machine, shock tube and jet stirred reactors covering a wide range of conditions pertinent to internal combustion engines. Simulation results are discussed focusing attention on the mixing effects of the fuel components.

  3. Degradation of a mixture of hydrocarbons, gasoline, and diesel oil additives by Rhodococcus aetherivorans and Rhodococcus wratislaviensis.

    PubMed

    Auffret, Marc; Labbé, Diane; Thouand, Gérald; Greer, Charles W; Fayolle-Guichard, Françoise

    2009-12-01

    Two strains, identified as Rhodococcus wratislaviensis IFP 2016 and Rhodococcus aetherivorans IFP 2017, were isolated from a microbial consortium that degraded 15 petroleum compounds or additives when provided in a mixture containing 16 compounds (benzene, toluene, ethylbenzene, m-xylene, p-xylene, o-xylene, octane, hexadecane, 2,2,4-trimethylpentane [isooctane], cyclohexane, cyclohexanol, naphthalene, methyl tert-butyl ether [MTBE], ethyl tert-butyl ether [ETBE], tert-butyl alcohol [TBA], and 2-ethylhexyl nitrate [2-EHN]). The strains had broad degradation capacities toward the compounds, including the more recalcitrant ones, MTBE, ETBE, isooctane, cyclohexane, and 2-EHN. R. wratislaviensis IFP 2016 degraded and mineralized to different extents 11 of the compounds when provided individually, sometimes requiring 2,2,4,4,6,8,8-heptamethylnonane (HMN) as a cosolvent. R. aetherivorans IFP 2017 degraded a reduced spectrum of substrates. The coculture of the two strains degraded completely 13 compounds, isooctane and 2-EHN were partially degraded (30% and 73%, respectively), and only TBA was not degraded. Significant MTBE and ETBE degradation rates, 14.3 and 116.1 mumol of ether degraded h(-1) g(-1) (dry weight), respectively, were measured for R. aetherivorans IFP 2017. The presence of benzene, toluene, ethylbenzene, and xylenes (BTEXs) had a detrimental effect on ETBE and MTBE biodegradation, whereas octane had a positive effect on the MTBE biodegradation by R. wratislaviensis IFP 2016. BTEXs had either beneficial or detrimental effects on their own degradation by R. wratislaviensis IFP 2016. Potential genes involved in hydrocarbon degradation in the two strains were identified and partially sequenced.

  4. Predicting the Virial coefficients and thermodynamic properties of a multicomponent mixture with application to the ternary mixture of CH{sub 2}F{sub 2} + CF{sub 3}CHF{sub 2} + CF{sub 3}CH{sub 2}F

    SciTech Connect

    Weber, L.A.

    1997-01-01

    A model for estimating second and third virial coefficients, which has been used successfully to represent the behavior of pure gases and binary mixtures, was applied to a ternary mixture. An estimate for the ternary third virial coefficient, C{sub 123}, was added to the model. Three experimentally determined binary interaction parameters were also used. The model has been applied to the ternary mixture CH{sub 2}F{sub 2} + CF{sub 3}CHF{sub 2} + CF{sub 3}CH{sub 2}F (R32 + R125 + R134a). The results are useful for calculating gas-phase densities, thermodynamic properties, and fugacities for phase equilibrium calculations. The use of such models leads to a considerable economy of effort in the case of multicomponent mixtures. Examples of the thermodynamic properties are given for the equimolar ternary mixture in the range from the dew-point temperature to 400 K at pressures of 0.5, 1, and 2 MPa. Calculated densities and speeds of sound are compared with new experimental values for a near-equimolar composition.

  5. Inhibition of the formation of benzo[a]pyrene adducts to DNA in A549 lung cells exposed to mixtures of polycyclic aromatic hydrocarbons.

    PubMed

    Genies, Camille; Jullien, Amandine; Lefebvre, Emmanuel; Revol, Morgane; Maitre, Anne; Douki, Thierry

    2016-09-01

    Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous pollutants, which exhibit carcinogenic properties especially in lungs. In the present work, we studied the effect of mixtures of 12 PAHs on the A549 alveolar cells. We first assess the ability of each PAH at inducing gene expression of phase I metabolization enzymes and at generating DNA adducts. A good correlation was found between these two endpoints. We then exposed cells to either binary mixtures of the highly genotoxic benzo[a]pyrene (B[a]P) with each PAH or complex mixtures of all studied PAHs mimicking by real emissions including combustion of wood, cigarette smoke, and atmospheres of garage, silicon factory and urban environments. Compared to pure B[a]P, both types of mixtures led to reduced CYP450 activity measured by the EROD test. A similar trend was observed for the formation of DNA adducts. Surprisingly, the complex mixtures were more potent than B[a]P used at the same concentration for the induction of genes coding for CYP. Our results stress the lack of additivity of the genotoxic properties of PAH in mixtures. Interestingly, an opposite synergy in the formation of B[a]P adducts were observed previously in hepatocytes. Our data also show that measurement of the metabolic activity rather than quantification of gene expression reflects the actual bioactivation of PAHs into DNA damaging species.

  6. Metal-Polycyclic Aromatic Hydrocarbon Mixture Toxicity in Hyalella azteca. 2. Metal Accumulation and Oxidative Stress as Interactive Co-toxic Mechanisms.

    PubMed

    Gauthier, Patrick T; Norwood, Warren P; Prepas, Ellie E; Pyle, Greg G

    2015-10-06

    Mixtures of metals and polycyclic aromatic hydrocarbons (PAHs) are commonly found in aquatic environments. Emerging reports have identified that more-than-additive mortality is common in metal-PAH mixtures. Individual aspects of PAH toxicity suggest they may alter the accumulation of metals and enhance metal-derived reactive oxygen species (ROS). Redox-active metals (e.g., Cu and Ni) are also capable of enhancing the redox cycling of PAHs. Accordingly, we explored the mutual effects redox-active metals and PAHs have on oxidative stress, and the potential for PAHs to alter the accumulation and/or homeostasis of metals in juvenile Hyalella azteca. Amphipods were exposed to binary mixtures of Cu, Cd, Ni, or V, with either phenanthrene (PHE) or phenanthrenequinone (PHQ). Mixture of Cu with either PAH produced striking more-than-additive mortality, whereas all other mixtures amounted to strictly additive mortality following 18-h exposures. We found no evidence to suggest that interactive effects on ROS production were involved in the more-than-additive mortality of Cu-PHE and Cu-PHQ mixtures. However, PHQ increased the tissue concentration of Cu in juvenile H. azteca, providing a potential mechanism for the observed more-than-additive mortality.

  7. Insight into unresolved complex mixtures of aromatic hydrocarbons in heavy oil via two-dimensional gas chromatography coupled with time-of-flight mass spectrometry analysis.

    PubMed

    Weng, Na; Wan, Shan; Wang, Huitong; Zhang, Shuichang; Zhu, Guangyou; Liu, Jingfu; Cai, Di; Yang, Yunxu

    2015-06-12

    The aromatic hydrocarbon fractions of five crude oils representing a natural sequence of increasing degree of biodegradation from the Liaohe Basin, NE, China, were analyzed using conventional gas chromatography-mass spectrometry (GC-MS) and comprehensive two-dimensional gas chromatography (GC×GC). Because of the limited peak capability and low resolution, compounds in the aromatic fraction of a heavily biodegraded crude oil that were analyzed by GC-MS appeared as unresolved complex mixtures (UCMs) or GC "humps". They could be separated based on their polarity by GC×GC. UCMs are composed mainly of aromatic biomarkers and aromatic hydrocarbons with branched alkanes or cycloalkanes substituents. The quantitative results achieved by GC×GC-FID were shown that monoaromatic hydrocarbons account for the largest number and mass of UCMs in the aromatic hydrocarbon fraction of heavily biodegraded crude oil, at 45% by mass. The number and mass of diaromatic hydrocarbons ranks second at 33% by mass, followed by the aromatic biomarker compounds, triaromatic, tetraaromatic, and pentaaromatic hydrocarbons, that account for 10%, 6%, 1.5%, and 0.01% of all aromatic compounds by mass, respectively. In the heavily biodegraded oil, compounds with monocyclic cycloalkane substituents account for the largest proportion of mono- and diaromatic hydrocarbons, respectively. The C4-substituted compounds account for the largest proportion of naphthalenes and the C3-substituted compounds account for the largest proportion of phenanthrenes, which is very different from non-biodegraded, slightly biodegraded, and moderately biodegraded crude oil. It is inferred that compounds of monoaromatic, diaromatic and triaromatic hydrocarbons are affected by biodegradation, that compounds with C1-, C2-substituents are affected by the increase in degree of biodegradation, and that their relative content decreased, whereas compounds with C3-substituents or more were affected slightly or unaffected, and their

  8. Activation of the aryl hydrocarbon receptor is the major toxic mode of action of an organic extract of a reference urban dust particulate matter mixture: the role of polycyclic aromatic hydrocarbons.

    PubMed

    Andrysík, Zdeněk; Vondráček, Jan; Marvanová, Soňa; Ciganek, Miroslav; Neča, Jiří; Pěnčíková, Kateřina; Mahadevan, Brinda; Topinka, Jan; Baird, William M; Kozubík, Alois; Machala, Miroslav

    2011-09-01

    Many of the toxic and carcinogenic effects of urban air pollution have been linked to polycyclic aromatic hydrocarbons (PAHs) adsorbed to airborne particulate matter (PM). The carcinogenic properties of PAHs in complex organic mixtures derived from PM have been chiefly attributed to their mutagenicity. Nevertheless, PAHs are also potent activators of the aryl hydrocarbon receptor (AhR), which may contribute to their nongenotoxic effects, including tumor promotion. As the genotoxicity of carcinogenic PAHs in complex mixtures derived from urban PM is often inhibited by other mixture constituents, the AhR-mediated activity of urban PM extracts might significantly contribute to the carcinogenic activity of such mixtures. In the present study, we used an organic extract of the urban dust standard reference material, SRM1649a, as a model mixture to study a range of toxic effects related to DNA damage and AhR activation. Both the organic extract and its neutral aromatic fraction formed a low number of DNA adducts per nucleotide in the liver epithelial WB-F344 cells model, without inducing DNA damage response, such as tumor suppressor p53 activation and apoptosis. In contrast, we found that this extract, as well as its neutral and polar fractions, were potent inducers of a range of AhR-mediated responses, including induction of the AhR-mediated transcription, such as cytochrome P450 1A1/1B1 expression, and the AhR-dependent cell proliferation. Importantly, these toxic events occurred at doses one order of magnitude lower than DNA damage. The AhR-mediated activity of the neutral fraction was linked to PAHs and their derivatives, as polychlorinated dibenzo-p-dioxins, dibenzofurans and biphenyls were only minor contributors to the overall AhR-mediated activity. Taken together, our data suggest that more attention should be paid to the AhR-dependent nongenotoxic events elicited by urban PM constituents, especially PAHs and their derivatives.

  9. X-ray structure of a hydroxylase-regulatory protein complex from a hydrocarbon-oxidizing multicomponent monooxygenase, Pseudomonas sp. OX1 phenol hydroxylase.

    PubMed

    Sazinsky, Matthew H; Dunten, Pete W; McCormick, Michael S; DiDonato, Alberto; Lippard, Stephen J

    2006-12-26

    Phenol hydroxylase (PH) belongs to a family of bacterial multicomponent monooxygenases (BMMs) with carboxylate-bridged diiron active sites. Included are toluene/o-xylene (ToMO) and soluble methane (sMMO) monooxygenase. PH hydroxylates aromatic compounds, but unlike sMMO, it cannot oxidize alkanes despite having a similar dinuclear iron active site. Important for activity is formation of a complex between the hydroxylase and a regulatory protein component. To address how structural features of BMM hydroxylases and their component complexes may facilitate the catalytic mechanism and choice of substrate, we determined X-ray structures of native and SeMet forms of the PH hydroxylase (PHH) in complex with its regulatory protein (PHM) to 2.3 A resolution. PHM binds in a canyon on one side of the (alphabetagamma)2 PHH dimer, contacting alpha-subunit helices A, E, and F approximately 12 A above the diiron core. The structure of the dinuclear iron center in PHH resembles that of mixed-valent MMOH, suggesting an Fe(II)Fe(III) oxidation state. Helix E, which comprises part of the iron-coordinating four-helix bundle, has more pi-helical character than analogous E helices in MMOH and ToMOH lacking a bound regulatory protein. Consequently, conserved active site Thr and Asn residues translocate to the protein surface, and an approximately 6 A pore opens through the four-helix bundle. Of likely functional significance is a specific hydrogen bond formed between this Asn residue and a conserved Ser side chain on PHM. The PHM protein covers a putative docking site on PHH for the PH reductase, which transfers electrons to the PHH diiron center prior to O2 activation, suggesting that the regulatory component may function to block undesired reduction of oxygenated intermediates during the catalytic cycle. A series of hydrophobic cavities through the PHH alpha-subunit, analogous to those in MMOH, may facilitate movement of the substrate to and/or product from the active site pocket

  10. A framework for the use of single-chemical transcriptomics data in predicting the hazards associated with complex mixtures of polycyclic aromatic hydrocarbons.

    PubMed

    Labib, Sarah; Williams, Andrew; Kuo, Byron; Yauk, Carole L; White, Paul A; Halappanavar, Sabina

    2016-11-17

    The assumption of additivity applied in the risk assessment of environmental mixtures containing carcinogenic polycyclic aromatic hydrocarbons (PAHs) was investigated using transcriptomics. MutaTMMouse were gavaged for 28 days with three doses of eight individual PAHs, two defined mixtures of PAHs, or coal tar, an environmentally ubiquitous complex mixture of PAHs. Microarrays were used to identify differentially expressed genes (DEGs) in lung tissue collected 3 days post-exposure. Cancer-related pathways perturbed by the individual or mixtures of PAHs were identified, and dose-response modeling of the DEGs was conducted to calculate gene/pathway benchmark doses (BMDs). Individual PAH-induced pathway perturbations (the median gene expression changes for all genes in a pathway relative to controls) and pathway BMDs were applied to models of additivity [i.e., concentration addition (CA), generalized concentration addition (GCA), and independent action (IA)] to generate predicted pathway-specific dose-response curves for each PAH mixture. The predicted and observed pathway dose-response curves were compared to assess the sensitivity of different additivity models. Transcriptomics-based additivity calculation showed that IA accurately predicted the pathway perturbations induced by all mixtures of PAHs. CA did not support the additivity assumption for the defined mixtures; however, GCA improved the CA predictions. Moreover, pathway BMDs derived for coal tar were comparable to BMDs derived from previously published coal tar-induced mouse lung tumor incidence data. These results suggest that in the absence of tumor incidence data, individual chemical-induced transcriptomics changes associated with cancer can be used to investigate the assumption of additivity and to predict the carcinogenic potential of a mixture.

  11. Kinetic Modeling of Gasoline Surrogate Components and Mixtures under Engine Conditions

    SciTech Connect

    Mehl, M; Pitz, W J; Westbrook, C K; Curran, H J

    2010-01-11

    Real fuels are complex mixtures of thousands of hydrocarbon compounds including linear and branched paraffins, naphthenes, olefins and aromatics. It is generally agreed that their behavior can be effectively reproduced by simpler fuel surrogates containing a limited number of components. In this work, an improved version of the kinetic model by the authors is used to analyze the combustion behavior of several components relevant to gasoline surrogate formulation. Particular attention is devoted to linear and branched saturated hydrocarbons (PRF mixtures), olefins (1-hexene) and aromatics (toluene). Model predictions for pure components, binary mixtures and multicomponent gasoline surrogates are compared with recent experimental information collected in rapid compression machine, shock tube and jet stirred reactors covering a wide range of conditions pertinent to internal combustion engines (3-50 atm, 650-1200K, stoichiometric fuel/air mixtures). Simulation results are discussed focusing attention on the mixing effects of the fuel components.

  12. Aspects of High-Resolution Gas Chromatography as Applied to the Analysis of Hydrocarbon Fuels and Other Complex Organic Mixtures. Volume 2. Survey of Sample Insertion Techniques.

    DTIC Science & Technology

    1985-06-01

    AD-A158 772 ASPECTS OF HIGH-RESOL.UTION GAS CHROMATOGRAPHY S 1ll APPLIED0 TO THE ANALYSIS 0..(U)1 DAYTON UNIV ON RESEARCH INST W A RUSEY ET AL. JUN...RESOLUTION GAS CHROMATOGRAPHY AS APPLIED TO THE ANALYSIS OF HYDROCARBON FUELS AND OTHER COMPLEX ORGANIC MIXTURES Volume II - Survey of Sample Insertion...NO. NO. 45433-6563 62203F 3048 05 91 11. TITLE (Include Security Classification) (cont’ d on reverse) ASPECTS OF HIGH-RESOLUTION GAS CHROMATOGRAPHY T

  13. Embryotoxic effects of benzo[a]pyrene, chrysene and 7,12-dimethylbenz[a]-anthracene in petroleum hydrocarbon mixtures in mallard ducks

    USGS Publications Warehouse

    Hoffman, D.J.; Gay, M.L.

    1981-01-01

    Studies with different avian species have revealed that surface applications of microliter amounts of some crude and fuel oils that coat less than 70% of the egg surface result in considerable reduction in hatching with teratogenicity and stunted growth. Other stUdies have shown that the embryo toxicity is dependent on the aromatic hydrocarbon content, further suggesting that the toxicity is due to causes other than asphyxia. In the present study the effects of three polycyclic aromatic hydrocarbons identified in petroleum were examined on mallard (Anas platyrhynchos) embryo development. Addition of benzo[a]pyrene (BaP), chrysene, or 7,7 2-dimethylbenz[ a]anthracene (DMBA) to a synthetic petroleum hydrocarbon mixture of known composition and relatively low embryotoxicity resulted in embryo toxicity that was enhanced or equal to that of crude oil when 10 :I was applied externally to eggs at 72 h of development. The order of ability to enhance embryo toxicity was DMBA > BaP > chrysene. The temporal pattern of embryonic death was similar to that reported after exposure to crude oil, with additional mortality occurring after outgrowth of the chorioallantois. Retarded growth, as reflected by embryonic body weight, crown-rump length, and bill length, was accompanied by teratogenicity. Abnormal embryos exhibited extreme stunting; eye, brain, and bill defects; and incomplete ossification. Gas chromatographic-mass spectral analysis of externally treated eggs showed the passage of aromatic hydrocarbons including chrysene through the shell and shell membranes to the developing embryos. These findings suggest that the presence of polycyclic aromatic hydrocarbons in petroleum, including BaP, chrysene, and DMBA, significantly enhances the overall embryotoxicity in avian species.

  14. [Using 2-DCOS to identify the molecular spectrum peaks for the isomer in the multi-component mixture gases Fourier transform infrared analysis].

    PubMed

    Zhao, An-Xin; Tang, Xiao-Jun; Zhang, Zhong-Hua; Liu, Jun-Hua

    2014-10-01

    The generalized two-dimensional correlation spectroscopy and Fourier transform infrared were used to identify hydrocarbon isomers in the mixed gases for absorption spectra resolution enhancement. The Fourier transform infrared spectrum of n-butane and iso-butane and the two-dimensional correlation infrared spectrum of concentration perturbation were used for analysis as an example. The all band and the main absorption peak wavelengths of Fourier transform infrared spectrum for single component gas showed that the spectra are similar, and if they were mixed together, absorption peaks overlap and peak is difficult to identify. The synchronous and asynchronous spectrum of two-dimensional correlation spectrum can clearly identify the iso-butane and normal butane and their respective characteristic absorption peak intensity. Iso-butane has strong absorption characteristics spectrum lines at 2,893, 2,954 and 2,893 cm(-1), and n-butane at 2,895 and 2,965 cm(-1). The analysis result in this paper preliminary verified that the two-dimensional infrared correlation spectroscopy can be used for resolution enhancement in Fourier transform infrared spectrum quantitative analysis.

  15. TESTING FOR ADDITIVITY IN THE LOW DOSE REGION OF AN ENVIRONMENTALLY RELEVANT MIXTURE OF 18 OLYHALOGENATED AROMATIC HYDROCARBONS.

    EPA Science Inventory

    A common default assumption in risk assessment of chemical mixtures is that the chemicals combine additively in the low dose region. Under additivity, with information from single chemical dose-response data, the risk associated with the mixture can be estimated. The objective ...

  16. Physicochemical and catalytic characteristics of La-H-ZSM-5 zeolite in converting dimethyl ether to the mixtures of gasoline hydrocarbons: Effect of ion exchange conditions

    NASA Astrophysics Data System (ADS)

    Kitaev, L. E.; Bukina, Z. M.; Yushchenko, V. V.; Ionin, D. A.; Kolesnichenko, N. V.; Khadzhiev, S. N.

    2014-03-01

    The effect of the manner and conditions of introducing lanthanum cations into NH4-ZSM-5 zeolite on the properties of catalysts for the conversion of dimethyl ether into the mixtures of gasoline hydrocarbons is studied. The physicochemical properties of synthesized catalysts are studied by means of temperature-programmed ammonia desorption, the adsorption of benzene, atomic absorption spectroscopy, differential scanning calorimetry, and thermogravimetry. It is shown that the degree to which lanthanum cations are replaced by ammonium cations both depends on the conditions of ion exchange in the zeolite and affects its acidity spectrum and the selectivity of the formation of paraffin hydrocarbons with isostructure. It is concluded that an increase in the amount of introduced lanthanum leads to an increase in the content of iso-paraffins from 69 to 76 wt % and a decrease in the content of aromatic hydrocarbons from 10.5 to 5.5 wt % and that of durene from 1.5 to 0.2 wt % in the products.

  17. PAH-CALUX, an optimized bioassay for AhR-mediated hazard identification of polycyclic aromatic hydrocarbons (PAHs) as individual compounds and in complex mixtures.

    PubMed

    Pieterse, B; Felzel, E; Winter, R; van der Burg, B; Brouwer, A

    2013-10-15

    Polycyclic aromatic hydrocarbons (PAHs) represent a class of ubiquitously occurring environmental compounds that are implicated in a wide range of toxicological effects. Routine measurement of PAH contamination generally involves chemical analytical analysis of a selected group of representatives, for example, EPA-16, which may result in underestimation of the PAH-related toxicity of a sample. Many high molecular weight PAHs are known ligands of the aryl hydrocarbon receptor (AhR), a nuclear receptor that mediates toxic effects related to these compounds. Making use of this property we developed a PAH CALUX assay, a mammalian, H4IIe- cell-based reporter assay for the hazard identification of total PAH mixtures. The PAH CALUX reporter cell line allows for specific, rapid (4 h exposure time) and reliable quantification of AhR-induced luciferase induction relative to benzo[a]pyrene (BaP), which is used as a positive reference PAH congener. Full dose response relationships with inductions over 100-fold were reached within only 2 h of exposure to BaP. The PAH CALUX is highly sensitive, that is, using a 4 h exposure time, a limit of detection (LOD) of 5.2 × 10(-11) M BaP was achieved, and highly accurate, that is, a repeatability of 5.9% and a reproducibility of 6.6% were established. Screening of a selection of PAHs that were prioritized by the European Union and/or the U.S. Environmental Protection Agency showed that the PAH CALUX bioassay has a high predictability, particularly for carcinogenic PAHs. Experiments with synthetic mixtures and reference materials containing complex PAH mixtures show the suitability of the assay for these types of applications. Moreover, the presented results suggest that application of the PAH CALUX will result in a lower risk of underestimation of the toxicity of a sample than chemical analytical approaches that focus on a limited set of prioritized compounds.

  18. Research Of Polytropic Exponent Changing For Influence Evaluation Of Actual Mixture Composition On Hydrocarbons Concentration Decreasing On Deep Throttling Operation

    NASA Astrophysics Data System (ADS)

    Smolenskaya, N. M.; Smolenskii, V. V.; Bobrovskij, I.

    2017-01-01

    The purpose of this article is to present study of polytropic exponent as rating of thermodynamic process in internal combustion motor operating to deep throttling in a subcase of idle running. It is necessary to consider the influence of hydrocarbon part in exhaust gases in a process of development a new internal combustion engines especially on deep throttling operation: on combustion procedure, on irregularity of exhaust gases composition.

  19. Kinetic of the OH-radical in high pressure plasmas of N_2/H_2O/hydrocarbons mixtures

    NASA Astrophysics Data System (ADS)

    Baravian, G.; Fresnet, F.; Magne, L.; Pasquiers, S.; Postel, C.; Puech, V.; Rousseau, A.

    2001-10-01

    Kinetic of the OH-radical has been studied in homogeneous plasmas achieved in a photo-triggered discharge device, in N_2/H_2O with C_2H4 or C_3H_6, at 460 mbar with 1.2 concentration and a deposited energy in the plasma equal to 92 J/l. Hydrocarbon concentration ranged from 50 ppm up to 1000 ppm. Using the same technique as for NO kinetic studies ( F. Fresnet, G. Baravian, L. Magne, S. Pasquiers, C. Postel, V. Puech, A. Rousseau, Appl. Phys. Lett., 77 (2000) 4118.), a time resolved LIF diagnostic has been performed to measure the OH-radical density up to 180 µs after the short current pulse excitation, 50 ns. At fixed deposited energy, the LIF signal rapidly decreases when hydrocarbon concentration increases. Measurements have been compared to predictions of a self-consistent 0D-model which takes into account a detailed kinetic scheme, including oxidation reactions of hydrocarbons by the radical which are important processes in flue gas non-thermal plasma treatment. Results are discussed.

  20. Mechanistic relationships between hepatic genotoxicity and carcinogenicity in male B6C3F1 mice treated with polycyclic aromatic hydrocarbon mixtures

    PubMed Central

    Phillips, Tracie D.; Richardson, Molly; Lisa Cheng, Yi-Shing; He, Lingyu; McDonald, Thomas J.; Cizmas, Leslie H.; Safe, Stephen H.; Donnelly, Kirby C.; Wang, Fen; Moorthy, Bhagavatula; Zhou, Guo-Dong

    2014-01-01

    The genotoxicity of a complex mixture [neutral fraction (NF)] from a wood preserving waste and reconstituted mixture (RM) mimicking the NF with seven major polycyclic aromatic hydrocarbons (PAHs) and benzo(a)pyrene (BaP) was investigated by determining DNA adducts and tumor incidence in male B6C3F1 mice exposed to 3 different doses of the chemical mixtures. The peak values of DNA adducts were observed after 24 h and the highest levels of PAH-DNA adducts were exhibited in mice administered NF+BaP, and the highest tumor incidence and mortality were also observed in this group. DNA adduct levels after 1, 7, or 21 d were significantly correlated with animal mortality and incidence of total tumors including liver, lung, and forestomach. However, only hepatic DNA adducts after 7 d significantly correlated with liver tumor incidence. Most proteins involved in DNA repair including ATM, pATR, Chk1, pChk1, DNA PKcs, XRCC1, FANCD2, Ku80, Mre11 and Brca2 were significantly lower in liver tumor tissue compared to non-tumor tissue. Expression of proteins involved in apoptosis and cell cycle regulation were also significantly different in tumor vs non-tumor tissues and it is possible that PAH-induced changes in these gene products are important for tumor development and growth. PMID:24888377

  1. Polycyclic aromatic hydrocarbons as skin carcinogens: Comparison of benzo[a]pyrene, dibenzo[def,p]chrysene and three environmental mixtures in the FVB/N mouse

    SciTech Connect

    Siddens, Lisbeth K.; Larkin, Andrew; Krueger, Sharon K.; Bradfield, Christopher A.; Waters, Katrina M.; Tilton, Susan C.; Pereira, Cliff B.; Löhr, Christiane V.; Arlt, Volker M.; Phillips, David H.; Williams, David E.; and others

    2012-11-01

    The polycyclic aromatic hydrocarbon (PAH), benzo[a]pyrene (BaP), was compared to dibenzo[def,p]chrysene (DBC) and combinations of three environmental PAH mixtures (coal tar, diesel particulate and cigarette smoke condensate) using a two stage, FVB/N mouse skin tumor model. DBC (4 nmol) was most potent, reaching 100% tumor incidence with a shorter latency to tumor formation, less than 20 weeks of 12-O-tetradecanoylphorbol-13-acetate (TPA) promotion compared to all other treatments. Multiplicity was 4 times greater than BaP (400 nmol). Both PAHs produced primarily papillomas followed by squamous cell carcinoma and carcinoma in situ. Diesel particulate extract (1 mg SRM 1650b; mix 1) did not differ from toluene controls and failed to elicit a carcinogenic response. Addition of coal tar extract (1 mg SRM 1597a; mix 2) produced a response similar to BaP. Further addition of 2 mg of cigarette smoke condensate (mix 3) did not alter the response with mix 2. PAH-DNA adducts measured in epidermis 12 h post initiation and analyzed by {sup 32}P post‐labeling, did not correlate with tumor incidence. PAH‐dependent alteration in transcriptome of skin 12 h post initiation was assessed by microarray. Principal component analysis (sum of all treatments) of the 922 significantly altered genes (p < 0.05), showed DBC and BaP to cluster distinct from PAH mixtures and each other. BaP and mixtures up-regulated phase 1 and phase 2 metabolizing enzymes while DBC did not. The carcinogenicity with DBC and two of the mixtures was much greater than would be predicted based on published Relative Potency Factors (RPFs). -- Highlights: ► Dibenzo[def,p]chrysene (DBC), 3 PAH mixtures, benzo[a]pyrene (BaP) were compared. ► DBC and 2 PAH mixtures were more potent than Relative Potency Factor estimates. ► Transcriptome profiles 12 hours post initiation were analyzed by microarray. ► Principle components analysis of alterations revealed treatment-based clustering. ► DBC gave a unique

  2. Polycyclic aromatic hydrocarbons as skin carcinogens: comparison of benzo[a]pyrene, dibenzo[def,p]chrysene and three environmental mixtures in the FVB/N mouse.

    PubMed

    Siddens, Lisbeth K; Larkin, Andrew; Krueger, Sharon K; Bradfield, Christopher A; Waters, Katrina M; Tilton, Susan C; Pereira, Cliff B; Löhr, Christiane V; Arlt, Volker M; Phillips, David H; Williams, David E; Baird, William M

    2012-11-01

    The polycyclic aromatic hydrocarbon (PAH), benzo[a]pyrene (BaP), was compared to dibenzo[def,p]chrysene (DBC) and combinations of three environmental PAH mixtures (coal tar, diesel particulate and cigarette smoke condensate) using a two stage, FVB/N mouse skin tumor model. DBC (4nmol) was most potent, reaching 100% tumor incidence with a shorter latency to tumor formation, less than 20 weeks of 12-O-tetradecanoylphorbol-13-acetate (TPA) promotion compared to all other treatments. Multiplicity was 4 times greater than BaP (400 nmol). Both PAHs produced primarily papillomas followed by squamous cell carcinoma and carcinoma in situ. Diesel particulate extract (1 mg SRM 1650b; mix 1) did not differ from toluene controls and failed to elicit a carcinogenic response. Addition of coal tar extract (1 mg SRM 1597a; mix 2) produced a response similar to BaP. Further addition of 2 mg of cigarette smoke condensate (mix 3) did not alter the response with mix 2. PAH-DNA adducts measured in epidermis 12 h post initiation and analyzed by ³²P post-labeling, did not correlate with tumor incidence. PAH-dependent alteration in transcriptome of skin 12 h post initiation was assessed by microarray. Principal component analysis (sum of all treatments) of the 922 significantly altered genes (p<0.05), showed DBC and BaP to cluster distinct from PAH mixtures and each other. BaP and mixtures up-regulated phase 1 and phase 2 metabolizing enzymes while DBC did not. The carcinogenicity with DBC and two of the mixtures was much greater than would be predicted based on published Relative Potency Factors (RPFs).

  3. Effects of currently used pesticides and their mixtures on the function of thyroid hormone and aryl hydrocarbon receptor in cell culture

    SciTech Connect

    Ghisari, Mandana; Long, Manhai; Tabbo, Agnese; Bonefeld-Jørgensen, Eva Cecilie

    2015-05-01

    Evidence suggest that exposure to pesticides can interfere with the endocrine system by multiple mechanisms. The endocrine disrupting potential of currently used pesticides in Denmark was analyzed as single compounds and in an equimolar mixture of 5 selected pesticides. The pesticides were previously analyzed for effects on the function of estrogen and androgen receptors, the aromatase enzyme and steroidogenesis in vitro. In this study, the effect on thyroid hormone (TH) function and aryl hydrocarbon receptor (AhR) transactivity was assessed using GH3 cell proliferation assay (T-screen) and AhR responsive luciferase reporter gene bioassay, respectively. Thirteen pesticides were analyzed as follows: 2-methyl-4-chlorophenoxyacetic acid, terbuthylazine, iodosulfuron-methyl-sodium, mesosulfuron-methyl, metsulfuron-methyl, chlormequat chloride, bitertanol, propiconazole, prothioconazole, mancozeb and its metabolite ethylene thiourea, cypermethrin, tau-fluvalinate, and malathion (currently banned in DK). In the T-screen, prothioconazole, malathion, tau-fluvalinate, cypermethrin, terbuthylazine and mancozeb significantly stimulated and bitertanol and propiconazole slightly reduced the GH3 cell proliferation. In the presence of triiodothyronine (T3), prothioconazole, tau-fluvalinate, propiconazole, cypermethrin and bitertanol significantly antagonized the T3-induced GH3 cell proliferation. Eleven of the tested pesticides agonized the AhR function, and bitertanol and prothioconazole inhibited the basal AhR activity. Bitertanol, propiconazole, prothioconazole and cypermethrin antagonized the TCDD-induced AhR transactivation at the highest tested concentration. The 5-component mixture had inducing effect but the combined effect could not be predicted due to the presence of bitertanol eliciting inhibitory effect. Upon removal of bitertanol from the mixture, the remaining four pesticides acted additively. In conclusion, our data suggest that pesticides currently used in Denmark

  4. Effect of the Si/Al ratio and of the zeolite structure on the performance of dealuminated zeolites for the reforming of hydrocarbon mixtures

    SciTech Connect

    Smirniotis, P.G.; Zhang, W.

    1996-09-01

    Various 12-membered ring pore zeolites were employed for the reforming of synthetic hydrocarbon mixtures which simulate industrial naphthas. All the zeolites were dealuminated to various extents. It was found that, under the present conditions over the samples which are slightly dealuminated, bimolecular-condensation reactions followed by recracking are responsible for the relatively large selectivities of C{sub 4} paraffins. The monomolecular cracking (via pentacoordinated carbonium ions) of the latter hydrocarbons is responsible for the large generation of CH{sub 4} from the cracking of C{sub 4} paraffins. When the Si/Al ratio increases, the selectivity of methane passes through a steep minimum, while those of C{sub 3}, C{sub 4}, and C{sub 5} pass through a maximum. It was also found that the zeolite pore structure is a very important factor for the time on stream activity of zeolite-based catalysts. Zeolites with reduced aluminum content and pore structures, which do not favor the formation of coke precursors in their cavities, can lead to very promising catalysts for acid-catalyzed reactions. From this study a 12-membered ring pore zeolite, which demonstrates minimal coke deactivation, was identified.

  5. Photoinduced Multicomponent Reactions.

    PubMed

    Garbarino, Silvia; Ravelli, Davide; Protti, Stefano; Basso, Andrea

    2016-12-12

    The combination of multicomponent approaches with light-driven processes opens up new scenarios in the area of synthetic organic chemistry, where the need for sustainable, atom- and energy-efficient reactions is increasingly urgent. Photoinduced multicomponent reactions are still in their infancy, but significant developments in this area are expected in the near future.

  6. Multicomponent Syntheses of Macrocycles

    NASA Astrophysics Data System (ADS)

    Masson, Géraldine; Neuville, Luc; Bughin, Carine; Fayol, Aude; Zhu, Jieping

    How to access efficiently the macrocyclic structure remained to be a challenging synthetic topic. Although many elegant approaches/reactions have been developed, construction of diverse collection of macrocycles is still elusive. This chapter summarized the recently emerged research area dealing with multicomponent synthesis of macrocycles, with particular emphasis on the approach named "multiple multicomponent reaction using two bifunctional building blocks".

  7. Experimental selectivity curves of gaseous binary mixtures of hydrocarbons and carbon dioxide on activated carbon and silica gel

    SciTech Connect

    Olivier, M.G.; Jadot, R.

    1998-07-01

    The selectivity curves of gaseous binary mixtures of ethane + ethylene, methane + carbon dioxide at 303 K and 700 kPa and butane + 2 methylpropane at 318 K and 200 kPa have been determined on activated carbon and silica gel using an original apparatus. In this paper, a brief description of this apparatus is given. The difference in behavior of these two adsorbents is discussed.

  8. Effects of currently used pesticides and their mixtures on the function of thyroid hormone and aryl hydrocarbon receptor in cell culture.

    PubMed

    Ghisari, Mandana; Long, Manhai; Tabbo, Agnese; Bonefeld-Jørgensen, Eva Cecilie

    2015-05-01

    Evidence suggest that exposure to pesticides can interfere with the endocrine system by multiple mechanisms. The endocrine disrupting potential of currently used pesticides in Denmark was analyzed as single compounds and in an equimolar mixture of 5 selected pesticides. The pesticides were previously analyzed for effects on the function of estrogen and androgen receptors, the aromatase enzyme and steroidogenesis in vitro. In this study, the effect on thyroid hormone (TH) function and aryl hydrocarbon receptor (AhR) transactivity was assessed using GH3 cell proliferation assay (T-screen) and AhR responsive luciferase reporter gene bioassay, respectively. Thirteen pesticides were analyzed as follows: 2-methyl-4-chlorophenoxyacetic acid, terbuthylazine, iodosulfuron-methyl-sodium, mesosulfuron-methyl, metsulfuron-methyl, chlormequat chloride, bitertanol, propiconazole, prothioconazole, mancozeb and its metabolite ethylene thiourea, cypermethrin, tau-fluvalinate, and malathion (currently banned in DK). In the T-screen, prothioconazole, malathion, tau-fluvalinate, cypermethrin, terbuthylazine and mancozeb significantly stimulated and bitertanol and propiconazole slightly reduced the GH3 cell proliferation. In the presence of triiodothyronine (T3), prothioconazole, tau-fluvalinate, propiconazole, cypermethrin and bitertanol significantly antagonized the T3-induced GH3 cell proliferation. Eleven of the tested pesticides agonized the AhR function, and bitertanol and prothioconazole inhibited the basal AhR activity. Bitertanol, propiconazole, prothioconazole and cypermethrin antagonized the TCDD-induced AhR transactivation at the highest tested concentration. The 5-component mixture had inducing effect but the combined effect could not be predicted due to the presence of bitertanol eliciting inhibitory effect. Upon removal of bitertanol from the mixture, the remaining four pesticides acted additively. In conclusion, our data suggest that pesticides currently used in Denmark

  9. Quantification of Complex Polycyclic Aromatic Hydrocarbon Mixtures in Standard Reference Materials Using GC×GC/ToF-MS

    PubMed Central

    Manzano, Carlos; Hoh, Eunha; Massey Simonich, Staci L.

    2014-01-01

    This research is the first to quantify complex PAH mixtures in NIST SRMs using comprehensive two-dimensional gas chromatography coupled to time-of-flight mass spectrometry (GC×GC/ToF-MS), with and without extract cleanup, and reports previously unidentified PAH isomers in the NIST SRMs. We tested a novel, high orthogonality GC column combination (LC-50×NSP-35), as well as with a commonly used column combination (Rtx-5ms×Rxi-17) for the quantification of a complex mixture of 85 different PAHs, including parent (PAHs), alkyl- (MPAHs), nitro- (NPAHs), oxy- (OPAHs), thio- (SPAHs), bromo- (BrPAHs), and chloro-PAHs (ClPAHs) in extracts from two standard reference materials: NIST SRM1650b (diesel particulate matter), with cleanup and NIST SRM1975 (diesel particulate extract), with and without extract cleanup. The LC-50×NSP-35 column combination resulted in an average absolute percent difference of 33.8%, 62.2% and 30.8% compared to the NIST certified PAH concentrations for NIST SRM1650b, NIST SRM1975 with cleanup and NIST SRM1975 without cleanup, while the Rtx-5ms×Rxi-17 resulted in an absolute percent difference of 38.6%, 67.2% and 79.6% for NIST SRM1650b, NIST SRM1975 with cleanup and NIST SRM1975 without cleanup, respectively. This GC×GC/ToF-MS method increases the number of PAHs detected and quantified in complex environmental extracts using a single chromatographic run. Without clean-up, 7 additional compounds were detected and quantified in NIST SRM1975 using the LC-50×NSP-35 column combination. These results suggest that the use of the LC-50×NSP-35 column combination in GC×GC/ToF-MS not only results in better chromatographic resolution and greater orthogonality for the separation of complex PAH mixtures, but can also be used for the accurate quantification of complex PAH mixtures in environmental extracts without cleanup. PMID:23932031

  10. Recovery of fatty acid from a solvated hydrocarbon mixture applicable to the Beaver-Herter solvent extraction process

    SciTech Connect

    Beaver, W.H.; Turpin, J.L.; Babcock, R.E.

    1985-01-01

    The Herter process is a patented solvent extraction enhanced oil recovery process. This process utilizes fatty acid as a solvent to mix with and reduce the viscosity of a heavy reservoir oil or a tar sand. This method differs from other solvent extraction oil recovery methods in that the recovery of the fatty acid solvent for further use, rather than the initial expense of the solvent, is the prime economic consideration. The fatty acid is recovered by saponification of the solvated oil mixture using an aqueous base, followed by migration of the resulting soap into the aqueous phase, and then desaponification of the aqueous phase.

  11. Identification and quantification of seven fused aromatic rings C26H14 peri-condensed benzenoid polycyclic aromatic hydrocarbons in a complex mixture of polycyclic aromatic hydrocarbons from coal tar.

    PubMed

    Oña-Ruales, Jorge O; Ruiz-Morales, Yosadara; Wise, Stephen A

    2016-04-15

    A methodology for the characterization of groups of polycyclic aromatic hydrocarbons (PAHs) using a combination of normal phase liquid chromatography with ultraviolet-visible spectroscopy (NPLC/UV-vis) and gas chromatography with mass spectrometry (GC/MS) was used for the identification and quantification of seven fused aromatic rings C26H14 peri-condensed benzenoid polycyclic aromatic hydrocarbons, PAHs, in standard reference material (SRM) 1597a, complex mixture of PAHs from coal tar. The NPLC/UV-vis isolated the fractions based on the number of aromatic carbons and the GC/MS allowed the identification and quantification of five of the nine C26H14 PAH isomers; naphtho[1,2,3,4-ghi]perylene, dibenzo[b,ghi]perylene, dibenzo[b,pqr]perylene, naphtho[8,1,2-bcd]perylene, and dibenzo[cd,lm]perylene using a retention time comparison with authentic reference standards. For the other four benzenoid isomers with no available reference standards the following two approaches were used. First, the annellation theory was used to achieve the potential identification of benzo[qr]naphtho[3,2,1,8-defg]chrysene, and second, the elution distribution in the GC fractions was used to support the potential identification of benzo[qr]naphtho[3,2,1,8-defg]chrysene and to reach the tentative identifications of dibenzo[a,ghi]perylene, naphtho[7,8,1,2,3-pqrst]pentaphene, and anthra[2,1,9,8-opqra]naphthacene. It is the first time that naphtho[1,2,3,4-ghi]perylene, dibenzo[b,ghi]perylene, dibenzo[b,pqr]perylene, naphtho[8,1,2-bcd]perylene, and dibenzo[cd,lm]perylene are quantified, and the first time that benzo[qr]naphtho[3,2,1,8-defg]chrysene is potentially identified, in any sample, in any context.

  12. Compound-Specific Stable Carbon Isotope Analysis of Low-Concentration Complex Hydrocarbon Mixtures from Natural Gas Hydrate Systems

    NASA Astrophysics Data System (ADS)

    Plummer, R. E.; Pohlman, J. W.; Coffin, R. B.

    2005-12-01

    A system has been developed to measure the stable carbon isotope (δ13C) composition of dissolved methane, ethane, and propane from natural sediment samples with headspace concentrations as low as 1 ppm using a modified Thermo Electron Trace gas chromatograph (GC) connected to a Finnigan Delta Plus XP isotope ratio mass spectrometer (IRMS). A cryofocusing inlet was connected to the GC which allows 0.02- to 15.0-ml injections into a 10-ml min-1 He carrier stream. Analytes from the variable-volume injection are focused into a small section of fused silica capillary, which is either empty or packed with Poraplot-Q, depending on the analyte(s) of interest. The analytes are then rapidly desorbed (100°C) onto the GC column (1.8 ml min-1), where they undergo separation, combustion and IRMS detection. The sensitivity of the IRMS was improved by the addition of high resistivity amplifiers so that measurements can be obtained with as little as 7-ng of carbon. The analytical precision (2σ) is less than 0.5‰ for methane analysis and less than 1‰ for ethane and propane analyses. The gases are standardized by tank CO2 which has been referenced to the NIST RM 8560 natural gas standard. The samples require no pretreatment, and can be analyzed rapidly (20 samples/day) and with minimal instrument training. Using this system, we have obtained complete stable carbon isotope ethane profiles from sediment cores from microbial and thermogenic gas hydrate regions on the Northern Cascadia Margin. We were able to differentiate the relative thermal and microbial contributions of the gases; and furthermore, we obtained clear evidence for ethanogenesis and ethane oxidation at depths similar to those where methanogenesis and anaerobic methane oxidation (AOM), respectively, occurred. This system will be utilized to analyze headspace and hydrate gas samples from IODP Leg 311. These data will allow us to fully characterize the thermogenic contributions and trace hydrocarbon biogeochemical

  13. {Sigma}PAH: A model to predict the toxicity of polynuclear aromatic hydrocarbon mixtures in field-collected sediments

    SciTech Connect

    Swartz, R.C.; Schults, D.W.; Ozretich, R.J.; Lamberson, J.O.; Cole, F.A.; Ferraro, S.P.; DeWitt, T.H.; Redmond, M.S.

    1995-11-01

    The {Sigma}PAH model estimates the probability of toxicity of PAH-contaminated sediments using a combination of equilibrium partitioning, WSAR, toxic unit, additivity, and concentration-response models. The sediment concentration of organic carbon and 13 PAH (polynuclear aromatic hydrocarbon) compounds were measured. Interstitial water concentrations (PAH{sub iw}) of the 13 compounds were predicted by equilibrium partitioning. The 10-d LC50 of each compound in interstitial water (10-d LC50{sub iw}) was predicted by a QSAR regression of 10-d LC50{sub iw} (From spiked sediment tests) to K{sub ow}. Toxic unit concentrations of individual compounds (TU{sub i}) were predicted as PAH{sub iw}/10-d LC50{sub iw}. The total number of toxic units of the 13 compounds ({Sigma}TU{sub i}) was calculated assuming the additivity of toxic effects of PAHs. {Sigma}TU{sub i} was used to predict the probability of toxicity to marine and estuarine amphipods using a concentration-response model derived from spiked sediment toxicity tests. The {Sigma}PAH model was verified by comparing predicted and observed toxicity in field-collected sediment samples. There was 86.6% correspondence and no significant difference between predicted and observed toxicity at PAH-contaminated sites. Ecological-effect levels predicted by the {Sigma}PAH model correspond with several sediment-quality guidelines.

  14. Compound- and mixture-specific differences in resistance to polycyclic aromatic hydrocarbons and PCB-126 among Fundulus heteroclitus subpopulations throughout the Elizabeth River estuary (Virginia, USA).

    PubMed

    Clark, Bryan W; Cooper, Ellen M; Stapleton, Heather M; Di Giulio, Richard T

    2013-09-17

    Atlantic killifish (Fundulus heteroclitus) inhabiting the Atlantic Wood Industries Superfund Site (Elizabeth River, Portsmouth, VA, USA) are resistant to the acute toxicity and cardiac teratogenesis caused by high levels of polycyclic aromatic hydrocarbons (PAHs) from creosote. The resistance is linked to down regulation of the aryl hydrocarbon receptor (AHR) pathway. We investigated the association between CYP1 activity, as a marker of potential AHR pathway suppression, and contaminant resistance in killifish subpopulations from sites throughout the estuary that varied significantly in PAH contamination level. Adult killifish and sediments were collected from seven sites across approximately 13.7 km in river length within the estuary and from a nearby reference site. Sediment PAH levels were determined using gas chromatography mass spectrometry. Embryos obtained via manual spawning were exposed to individual AHR agonists and PAH mixtures 24 h post fertilization (hpf); CYP1 activity was determined by in ovo ethoxyresorufin-o-deethylase (EROD) at 96 hpf, and cardiac deformity severity was scored at 144 hpf. The total PAH levels measured among the sites varied from approximately 200 to 125,000 ng/g dry sediment. Overall, the resistance to teratogenesis was strongest in the subpopulations from sites in or closest to the major PAH contamination sites, but even embryos from less-contaminated sites within the Elizabeth River demonstrated at least partial resistance to many challenges. Surprisingly, all of the subpopulations tested were highly resistant to PCB-126 (3,3',4,4',5-pentachlorobiphenyl). However, the degree of CYP1 activity response varied significantly among subpopulations and did not always correlate strongly with resistance to teratogenesis; some subpopulations resisted the cardiac teratogenesis caused by the challenges at doses that still elicited strong EROD induction. Our results suggest that there is variation in the adaptive phenotype exhibited by

  15. Spatially resolved multicomponent gels

    NASA Astrophysics Data System (ADS)

    Draper, Emily R.; Eden, Edward G. B.; McDonald, Tom O.; Adams, Dave J.

    2015-10-01

    Multicomponent supramolecular systems could be used to prepare exciting new functional materials, but it is often challenging to control the assembly across multiple length scales. Here we report a simple approach to forming patterned, spatially resolved multicomponent supramolecular hydrogels. A multicomponent gel is first formed from two low-molecular-weight gelators and consists of two types of fibre, each formed by only one gelator. One type of fibre in this ‘self-sorted network’ is then removed selectively by a light-triggered gel-to-sol transition. We show that the remaining network has the same mechanical properties as it would have done if it initially formed alone. The selective irradiation of sections of the gel through a mask leads to the formation of patterned multicomponent networks, in which either one or two networks can be present at a particular position with a high degree of spatial control.

  16. Enhanced degradation of a mixture of polycyclic aromatic hydrocarbons by a defined microbial consortium in a two-phase partitioning bioreactor.

    PubMed

    Vandermeer, Krista D; Daugulis, Andrew J

    2007-04-01

    Biological treatment methods are effective at destroying polycyclic aromatic hydrocarbons (PAHs), and some of the highest rates of PAH degradation have been achieved using two-phase-partitioning bioreactors (TPPBs). TPPBs consist of a cell-containing aqueous phase and a biocompatible and immiscible organic phase that partitions toxic and/or recalcitrant substrates to the cells based on their metabolic demand and on maintaining the thermodynamic equilibrium of the system. In this study, the degradation of a 5-component mixture of high and low molecular weight PAHs by a defined microbial consortium of Sphingomonas aromaticivorans B0695 and Sphingomonas paucimobilis EPA505 in a TPPB was examined. The extremely low aqueous solubilities of the high molecular weight (HMW) PAHs significantly reduce their bioavailability to cells, not only in the environment, but in TPPBs as well. That is, in the two-phase system, the originally selected solvent, dodecane, was found to sequester the HMW PAHs from the cells in the aqueous phase due to the inherent high solubility of the hydrophobic compounds in this solvent. To circumvent this limitation, the initial PAH concentrations in dodecane were increased to sufficient levels in the aqueous phase to support degradation: LMW PAHs (naphthalene, phenanthrene) and fluoranthene were degraded completely in 8 h, while the HMW PAHs, pyrene and benzo[a]pyrene, were degraded by 64% and 11%, at rates of 42.9 mg l(-1) d(-1) and 7.5 mg l(-1) d(-1), respectively. Silicone oil has superior PAH partitioning abilities compared to dodecane for the HMW PAHs, and was used to improve the extent of degradation for the PAH mixture. Although silicone oil increased the bioavailability of the HMW PAHs and greater extents of biodegradation were observed, the rates of degradation were lower than that obtained in the TPPB employing dodecane.

  17. Identification and quantification of known polycyclic aromatic hydrocarbons and pesticides in complex mixtures using fluorescence excitation-emission matrices and parallel factor analysis.

    PubMed

    Ferretto, Nicolas; Tedetti, Marc; Guigue, Catherine; Mounier, Stéphane; Redon, Roland; Goutx, Madeleine

    2014-07-01

    Polycyclic aromatic hydrocarbons (PAHs) and pesticides are among the most widespread organic contaminants in aquatic environments. Because of their aromatic structure, PAHs and pesticides have intrinsic fluorescence properties in the ultraviolet/blue spectral range. In this study, excitation-emission matrix (EEM) fluorescence spectroscopy and parallel factor (PARAFAC) analysis were used to characterise and discriminate fluorescence signatures of nine PAHs and three pesticides at the μg L(-1) level in the presence of humic substances (0.1-10 mgCL(-1)). These contaminants displayed a diversity of fluorescence signatures regarding spectral position (λEx: 220-335 nm, λEm: 310-414 nm), Stokes shift (39-169 nm) and number of peaks (1-8), with detection limits ranging from 0.02 to 1.29μgL(-1). The EEM/PARAFAC method applied to mixtures of PAHs with humic substances validated a seven-component model that included one humic-like fluorophore and six PAH-like fluorophores. The EEM/PARAFAC method applied to mixtures of pesticides with humic substances validated a six-component model that included one humic-like fluorophore and three pesticide-like fluorophores. The EEM/PARAFAC method adequately quantified most of the contaminants for humic substance concentrations not exceeding 2.5 mg CL(-1). The application of this method to natural (marine) samples was demonstrated through (1) the match between the Ex and Em spectra of PARAFAC components and the Ex and Em spectra of standard PAHs, and (2) the good linear correlations between the fluorescence intensities of PARAFAC components and the PAH concentrations determined by GC-MS.

  18. The role of CYP1A inhibition in the embryotoxic interactions between hypoxia and polycyclic aromatic hydrocarbons (PAHs) and PAH mixtures in zebrafish (Danio rerio)

    PubMed Central

    Fleming, Carrie R.; Di Giulio, Richard T.

    2013-01-01

    Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous environmental pollutants with elevated concentrations in waters that may also experience hypoxia. Previous research has shown interactions between hypoxia and some PAHs (fluoranthene, α-naphthoflavone) but no interaction with others (benzo[a]pyrene (BaP), β-naphthoflavone). Here we examine how hypoxia (7.4% oxygen, ~35% of normoxia) affects the embryotoxicity of PAHs that act through different mechanisms and the role that CYP1A inhibition may play in these interactions. 500 μg/L BaP and 1-200 μg/L benzo[k]fluoranthene (BkF) interacted synergistically with hypoxia to induce pericardial edema in developing zebrafish (Danio rerio). Hypoxia protected from the embryotoxicity of pyrene (PY) and had no effect on the toxicity of polychlorinated biphenyl-126. Despite previous reports of other CYP1A inhibitors interacting with hypoxia, up to 2000 μg/L dibenzothiophene, 2-aminoanthracene (AA), and carbazole (CB) all failed to induce embryotoxicity under normoxic or hypoxic conditions. The toxicity of PAH mixtures—including binary mixtures of BaP/AA and BaP/CB and two environmentally relevant, complex mixtures—were exacerbated severely by hypoxia to induce or worsen pericardial edema and cause mortality. The interactions between hypoxia and BkF and PY were closely mimicked by morpholino knockdown of CYP1A, indicating a potential role for metabolism of these compounds in their toxicity. Our results indicate that various PAHs may exhibit synergistic, antagonistic or additive toxicity with hypoxia. The enhanced toxicity of environmental mixtures of PAHs under hypoxia suggests that risk assessments that do not take into account potential interactions with hypoxia may underestimate the threat of PAHs to fish in contaminated sites. PMID:21706407

  19. Insect Adhesion Secretions: Similarities and Dissimilarities in Hydrocarbon Profiles of Tarsi and Corresponding Tibiae.

    PubMed

    Gerhardt, Heike; Betz, Oliver; Albert, Klaus; Lämmerhofer, Michael

    2016-08-01

    Spatially controlled in vivo sampling by contact solid phase microextraction with a non-coated silica fiber combined with gas chromatography-mass spectrometry (GC-MS) was utilized for hydrocarbon profiling in tarsal adhesion secretions of four insect species (Nicrophorus vespilloides, Nicrophorus nepalensis, Sagra femorata, and Gromphadorhina portentosa) by using distinct adhesion systems, viz. hairy or smooth tarsi. For comparison, corresponding samples from tibiae, representing the general cuticular hydrocarbon profile, were analyzed to enable the statistical inference of active molecular adhesion principles in tarsal secretions possibly contributed by specific hydrocarbons. n-Alkanes, monomethyl and dimethyl alkanes, alkenes, alkadienes, and one aldehyde were detected. Multivariate statistical analysis (principal component and orthogonal partial least square discriminant analyses) gave insights into distinctive molecular features among the various insect species and between tarsus and tibia samples. In general, corresponding hydrocarbon profiles in tarsus and tibia samples largely resembled each other, both qualitatively and in relative abundances as well. However, several specific hydrocarbons showed significantly different relative abundances between corresponding tarsus and tibia samples, thus indicating that such differences of specific hydrocarbons in the complex mixtures might constitute a delicate mechanism for fine-tuning the reversible attachment performances in tarsal adhesive fluids that are composed of substances originating from the same pool as cuticular hydrocarbons. Caused by melting point depression, the multicomponent tarsal adhesion secretion, made up of straight chain alkanes, methyl alkanes, and alkenes will have a semi-solid, grease-like consistency, which might provide the basis for a good reversible attachment performance.

  20. Resolution and quantification of complex mixtures of polycyclic aromatic hydrocarbons in heavy fuel oil sample by means of GC × GC-TOFMS combined to multivariate curve resolution.

    PubMed

    Parastar, Hadi; Radović, Jagoš R; Jalali-Heravi, Mehdi; Diez, Sergi; Bayona, Josep Maria; Tauler, Roma

    2011-12-15

    Comprehensive two-dimensional gas chromatography time-of-flight mass spectrometry (GC × GC-TOFMS) combined to multivariate curve resolution-alternating least-squares (MCR-ALS) is proposed for the resolution and quantification of very complex mixtures of compounds such as polycyclic aromatic hydrocarbons (PAHs) in heavy fuel oil (HFO). Different GC × GC-TOFMS data slices acquired during the analysis of HFO samples and PAH standards were simultaneously analyzed using the MCR-ALS method to resolve the pure component elution profiles in the two chromatographic dimensions as well as their pure mass spectra. Outstandingly, retention time shifts within and between GC × GC runs were not affecting the results obtained using the proposed strategy and proper resolution of strongly coeluted compounds, baseline and background contributions was achieved. Calibration curves built up with standard samples of PAHs allowed the quantification of ten of them in HFO aromatic fractions. Relative errors in their estimated concentrations were in all cases below 6%. The obtained results were compared to those obtained by commercial software provided with GC × GC-TOFMS instruments and to Parallel Factor Analysis (PARAFAC). Inspection of these results showed improvement in terms of data fitting, elution process description, concentration relative errors and relative standard deviations.

  1. Reutilization of waste scrap tyre as the immobilization matrix for the enhanced bioremoval of a monoaromatic hydrocarbons, methyl tert-butyl ether, and chlorinated ethenes mixture from water.

    PubMed

    Lu, Qihong; de Toledo, Renata Alves; Xie, Fei; Li, Junhui; Shim, Hojae

    2017-04-01

    BTEX (benzene, toluene, ethylbenzene, ortho-, meta-, and para-xylenes), methyl tert-butyl ether (MTBE), cis-1,2-dichloroethylene (cis-DCE), and trichloroethylene (TCE) are among the major soil and groundwater contaminants frequently co-existing, as a result of their widespread uses. Pseudomonas plecoglossicida was immobilized on waste scrap tyre to remove these contaminants mixture from synthetic contaminated water. The microbial activity was enhanced in the immobilized system, shown by the higher colony forming units (CFUs) (40%), while BTEX were used as growth substrates. The adsorption capacity of tyres toward contaminants reached a maximum within one day, with BTEX (76.3%) and TCE (64.3%) showing the highest sorption removal capacities, followed by cis-DCE (30.0%) and MTBE (11.0%). The adsorption data fitted the Freundlich isotherm with a good linear correlation (0.989-0.999) for the initial contaminants concentration range applied (25-125mg/L). The monoaromatic hydrocarbons were almost completely removed in the immobilized system and the favourable removal efficiencies of 78% and 90% were obtained for cis-DCE and TCE, respectively. The hybrid (biological, immobilization/physical, sorption) system was further evaluated with the contaminants spiked intermittently for the stable performance. The addition of mineral salt medium further enhanced the bioremoval of contaminants by stimulating the microbial growth to some extent.

  2. Effects of aflatoxin B₁, fumonisin B₁ and their mixture on the aryl hydrocarbon receptor and cytochrome P450 1A induction.

    PubMed

    Mary, Verónica S; Valdehita, Ana; Navas, José M; Rubinstein, Héctor R; Fernández-Cruz, María L

    2015-01-01

    Aflatoxin B1 (AFB1) and fumonisin B1 (FB1) are mycotoxins widely found as cereal contaminants and their co-occurrence in corn has been associated with a high incidence of liver cancer. Both toxins are immunotoxic, with AFB1 being a procarcinogen, and its bioactivation through specific cytochrome P450 (Cyp) enzymes, such as Cyp1A, being a requirement for hepatocarcinogenic and toxic activities. This study evaluated the effects of these mycotoxins, alone or combined, on activation and expression of Cyp1A and its transcription factor aryl hydrocarbon receptor (Ahr) in hepatoma cell line H4IIE and spleen mononuclear cells of rats. The results demonstrate that in H4IIE cells, AFB1 induced an increase in Cyp1A activity and cyp1A transcription, associated with an enhanced Ahr activity, which suggests that this toxin can act as an Ahr agonist. Moreover, FB1 caused a small rise in Cyp1A activity and cyp1A expression. Similarly in spleen cells, AFB1 and FB1 induced overexpression of cyp1A and ahr genes. This work shows that the response potency was significantly higher for the mixture, indicating the existence of an interaction between both toxins. This study proposes the Ahr pathway activation as a toxicity mechanism of AFB1 and FB1, and highlights that FB1 may increase AFB1 bioactivation.

  3. Effect of SO2 concentration on SOA formation in a photorreactor from a mixture of anthropogenic hydrocarbons and HONO

    NASA Astrophysics Data System (ADS)

    García Vivanco, Marta; Santiago, Manuel; García Diego, Cristina; Borrás, Esther; Ródenas, Milagros; Martínez-Tarifa, Adela

    2010-05-01

    Sulfur dioxide (SO2) is an important urban atmospheric pollutant, mainly produced by the combustion of fossil fuels containing sulfur. In the atmosphere, SO2 can react with OH radicals to form sulfuric acid, which can condense to form acidic aerosol. Sulfuric acid particles act as an acid catalyst for some heterogeneous carbonyl reactions like hydration, polymerization or acetals formation, which may lead to a large increase on SOA mass. In order to evaluate the effect of the SO2 concentration on SOA formation, 3 experiments were performed during the campaign carried out by CIEMAT on the EUPHORE facility (CEAM, Valencia, Spain) during June- July 2008. The objective of the campaign was to evaluate the effect of different experimental conditions on SOA formation from the photooxidation of some anthropogenic and biogenic VOCs using HONO as oxidant. Experiment on 6/17/08 was selected as base case (no SO2 was introduced) and experiments 6/26/08 and 7/1/08 were selected as high SO2 (2600 ug/m3) and low SO2 (60 ug/m3) concentration experiments respectively. In the three experiments a mixture of toluene, 1,3,5-TMB (trimethylbenzene), o-xylene and octane was selected as the parent VOCs. Single and coupled to mass spectroscopy gas cromatography (GC and GC/MS), as well as high performance liquid chromatography (HPLC) and Fourier transform infrared spectroscopy (FTIR) were used to measure the initial VOCs and oxidant concentrations decay and the formation of gas phase oxidation products through the experiments. Aerosol size distribution and concentration were measured with SMPS (scanning mobility particle sizer) and TEOM (tapered element oscillating monitor) respectively. In addition, analysis of the organic and inorganic aerosol content was also performed via filter sampling followed by GC/MS and ionic chromatography (for organic and inrganic content respectively). Comparing the filters collected in the three experiments, clearly the largest mass aerosol formation is observed

  4. Membrane separation of hydrocarbons

    DOEpatents

    Funk, Edward W.; Kulkarni, Sudhir S.; Chang, Y. Alice

    1986-01-01

    Mixtures of heavy oils and light hydrocarbons may be separated by passing the mixture over a polymeric membrane which comprises a polymer capable of maintaining its integrity in the presence of hydrocarbon compounds at temperature ranging from about ambient to about 100.degree. C. and pressures ranging from about 50 to about 1000 psi. The membranes which possess pore sizes ranging from about 10 to about 500 Angstroms are cast from a solvent solution and recovered.

  5. Relevance of Urinary 3-Hydroxybenzo(a)pyrene and 1-Hydroxypyrene to Assess Exposure to Carcinogenic Polycyclic Aromatic Hydrocarbon Mixtures in Metallurgy Workers

    PubMed Central

    Barbeau, Damien; Persoons, Renaud; Marques, Marie; Hervé, Claire; Laffitte-Rigaud, Gilbert; Maitre, Anne

    2014-01-01

    Objectives: In metallurgy, workers are exposed to mixtures of polycyclic aromatic hydrocarbons (PAHs) in which some compounds are carcinogenic. Biomonitoring of PAH exposure has been performed by measuring urinary 1-hydroxypyrene (1-OHP), a metabolite of pyrene which is not carcinogenic. This study investigated the use of 3-hydroxybenzo(a)pyrene (3-OHBaP), a metabolite of benzo(a)pyrene (BaP) which is the main carcinogenic component in PAHs, to improve carcinogen exposure assessment. Methods: We included 129 metallurgy workers routinely exposed to PAHs during working hours. Urinary samples were collected at three sampling times at the beginning and at the end of the working week for 1-OHP and 3-OHBaP analyses. Results: Workers in anode production showed greater exposure to both biomarkers than those in cathode or silicon production, with respectively, 71, 40, and 30% of 3-OHBaP concentrations exceeding the value of 0.4 nmol mol−1 creatinine. No difference was observed between the 3-OHBaP levels found at the end of the penultimate workday shift and those at the beginning of the last workday shift. Within these plants, the 1-OHP/3-OHBaP ratios varied greatly according to the workers’ activity and emission sources. Using linear regression between these two metabolites, the 1-OHP level corresponding to the guidance value for 3-OHBaP ranged from 0.7 to 2.4 µmol mol−1 creatinine, depending on the industrial sector. Conclusions: This study emphasizes the interest of monitoring urinary 3-OHBaP at the end of the last workday shift when working week exposure is relatively steady, and the irrelevance of a single guideline value for 1-OHP when assessing occupational health risk. PMID:24504174

  6. Effects of pesticide compounds (chlorothalonil and mancozeb) and benzo[a]pyrene mixture on aryl hydrocarbon receptor, p53 and ubiquitin gene expression levels in haemocytes of soft-shell clams (Mya arenaria).

    PubMed

    Pariseau, Julie; McKenna, Patricia; Aboelkhair, Mohammed; Saint-Louis, Richard; Pelletier, Emilien; Davidson, T Jeffrey; Tremblay, Réjean; Berthe, Franck C J; Siah, Ahmed

    2011-11-01

    The aim of this study is to investigate the effects of the pesticides/polycyclic aromatic hydrocarbon mixture on aryl hydrocarbon receptor (AhR), p53 and ubiquitin mRNA level in haemocytes of Mya arenaria exposed to a mixture of chlorothalonil, mancozeb and benzo[a]pyrene (BaP) for 48 and 72 h. AhR, p53 and ubiquitin gene expression levels were quantified using quantitative Real-time PCR. For robust and accurate quantification of transcripts, suitable housekeeping genes were selected from four sets of ribosomal and elongation factors transcripts previously sequenced from Mya arenaria using geNorm open source software. Quantitative Real-time PCR data exhibited a significantly high expression of AhR after 72 h of exposure (P ≤ 0.05). p53 gene expression seems to be up-regulated by the mixture after 48 h, however not significantly; but the level of p53 mRNA is down-regulated by the xenobiotics between 48 and 72 h after exposure. This study postulates that AhR mRNA levels could be used as an indicator of the exposure of clams' haemocytes to a mixture of xenobiotics such as chlorothalonil, mancozeb and BaP. However, further studies have to be pursued in order to unravel the molecular mechanisms involved in the p53 signaling pathway.

  7. Multicomponent Implant Releasing Dexamethasone

    NASA Astrophysics Data System (ADS)

    Nikkola, L.; Vapalahti, K.; Ashammakhi, N.

    2008-02-01

    Several inflammatory conditions are usually treated with corticosteroids. There are various problems like side effects with traditional applications of steroids, e.g. topical, or systemic routes. Local drug delivery systems have been studied and developed to gain more efficient administration with fewer side effects. Earlier, we reported on developing Dexamethasone (DX) releasing biodegradable fibers. However, their drug release properties were not satisfactory in terms of onset of drug release. Thus, we assessed the development of multicomponent (MC) implant to enhance earlier drug release from such biodegradable fibers. Poly (lactide-co-glycolide) (PLGA) and 2 wt-% and 8 wt-% DX were compounded and extruded with twin-screw extruder to form of fibers. Some of the fibers were sterilized to obtain a change in drug release properties. Four different fiber classes were studied: 2 wt-%, 8 wt-%, sterilized 2 wt-%, and sterilized 8 wt-%. 3×4 different DX-releasing fibers were then heat-pressed to form one multicomponent rod. Half of the rods where sterilized. Drug release was measured from initial fibers and multicomponent rods using a UV/VIS spectrometer. Shear strength and changes in viscosity were also measured. Drug release studies showed that drug release commenced earlier from multicomponent rods than from component fibers. Drug release from multicomponent rods lasted from day 30 to day 70. The release period of sterilized rods extended from day 23 to day 57. When compared to the original component fibers, the drug release from MC rods commenced earlier. The initial shear strength of MC rods was 135 MPa and decreased to 105 MPa during four weeks of immersion in phosphate buffer solution. Accordingly, heat pressing has a positive effect on drug release. After four weeks in hydrolysis, no disintegration was observed.

  8. Biodegradation pattern of hydrocarbons from a fuel oil-type complex residue by an emulsifier-producing microbial consortium.

    PubMed

    Nievas, M L; Commendatore, M G; Esteves, J L; Bucalá, V

    2008-06-15

    The biodegradation of a hazardous waste (bilge waste), a fuel oil-type complex residue from normal ship operations, was studied in a batch bioreactor using a microbial consortium in seawater medium. Experiments with initial concentrations of 0.18 and 0.53% (v/v) of bilge waste were carried out. In order to study the biodegradation kinetics, the mass of n-alkanes, resolved hydrocarbons and unresolved complex mixture (UCM) hydrocarbons were assessed by gas chromatography (GC). Emulsification was detected in both experiments, possibly linked to the n-alkanes depletion, with differences in emulsification start times and extents according to the initial hydrocarbon concentration. Both facts influenced the hydrocarbon biodegradation kinetics. A sequential biodegradation of n-alkanes and UMC was found for the higher hydrocarbon content. Being the former growth associated, while UCM biodegradation was a non-growing process showing enzymatic-type biodegradation kinetics. For the lower hydrocarbon concentration, simultaneous biodegradation of n-alkanes and UMC were found before emulsification. Nevertheless, certain UCM biodegradation was observed after the medium emulsification. According to the observed kinetics, three main types of hydrocarbons (n-alkanes, biodegradable UCM and recalcitrant UCM) were found adequate to represent the multicomponent substrate (bilge waste) for future modelling of the biodegradation process.

  9. General Model for Multicomponent Ablation Thermochemistry

    NASA Technical Reports Server (NTRS)

    Milos, Frank S.; Marschall, Jochen; Rasky, Daniel J. (Technical Monitor)

    1994-01-01

    A previous paper (AIAA 94-2042) presented equations and numerical procedures for modeling the thermochemical ablation and pyrolysis of thermal protection materials which contain multiple surface species. This work describes modifications and enhancements to the Multicomponent Ablation Thermochemistry (MAT) theory and code for application to the general case which includes surface area constraints, rate limited surface reactions, and non-thermochemical mass loss (failure). Detailed results and comparisons with data are presented for the Shuttle Orbiter reinforced carbon-carbon oxidation protection system which contains a mixture of sodium silicate (Na2SiO3), silica (SiO2), silicon carbide (SiC), and carbon (C).

  10. Hydrocarbon fuel detergent

    SciTech Connect

    Meyer, G.R.; Lyons, W.R.

    1990-01-23

    This patent describes a hydrocarbon fuel composition comprising: a hydrocarbon fuel; and a detergent amount of a detergent comprising an alkenylsuccinimide prepared by reacting an alkenylsuccinic acid or anhydride with a mixture of amines, wherein at least 90 weight percent of the alkenyl substituent is derived from an olefin having a carbon chain of from 10 to 30 carbons or mixtures thereof, and wherein the alkenylsuccinic acid or anhydride is reacted with the mixture of amines at a mole ratio of 0.8 to 1.5 moles of the amines per mole of the alkenylsuccinic acid or anhydride.

  11. Polynuclear aromatic hydrocarbons for fullerene synthesis in flames

    DOEpatents

    Alford, J. Michael; Diener, Michael D.

    2006-12-19

    This invention provides improved methods for combustion synthesis of carbon nanomaterials, including fullerenes, employing multiple-ring aromatic hydrocarbon fuels selected for high carbon conversion to extractable fullerenes. The multiple-ring aromatic hydrocarbon fuels include those that contain polynuclear aromatic hydrocarbons. More specifically, multiple-ring aromatic hydrocarbon fuels contain a substantial amount of indene, methylnapthalenes or mixtures thereof. Coal tar and petroleum distillate fractions provide low cost hydrocarbon fuels containing polynuclear aromatic hydrocarbons, including without limitation, indene, methylnapthalenes or mixtures thereof.

  12. Temperature- and pressure-dependent absorption cross sections of gaseous hydrocarbons at 3.39 µm

    NASA Astrophysics Data System (ADS)

    Klingbeil, A. E.; Jeffries, J. B.; Hanson, R. K.

    2006-07-01

    The pressure- and temperature-dependent absorption cross sections of several neat hydrocarbons and multi-component fuels are measured using a 3.39 µm helium-neon laser. Absorption cross section measurements are reported for methane, ethylene, propane, n-heptane, iso-octane, n-decane, n-dodecane, JP-10, gasoline and jet-A with an estimated uncertainty of less than 3.5%. The experimental conditions range from 298 to 673 K and from 500 to 2000 Torr with nitrogen as the bath gas. An apparatus is designed to facilitate these measurements, and specific care is taken to ensure the compositional accuracy of the hydrocarbon/N2 mixtures. The absorption cross sections of the smallest hydrocarbons, methane and ethylene, vary with temperature and pressure. The cross sections of larger hydrocarbons show negligible dependence on pressure and only a weak dependence on temperature. The reported data increase the range of conditions and the number of hydrocarbons for which cross section measurements are available at the HeNe laser wavelength.

  13. Hydrocarbon pneumonia

    MedlinePlus

    Pneumonia - hydrocarbon ... Coughing Fever Shortness of breath Smell of a hydrocarbon product on the breath Stupor (decreased level of ... Most children who drink or inhale hydrocarbon products and develop ... hydrocarbons may lead to rapid respiratory failure and death.

  14. Mechanics of Turbulence of Multicomponent Gases

    NASA Astrophysics Data System (ADS)

    Marov, Mikhail Ya.; Kolesnichenko, Aleksander V.

    2002-02-01

    Turbulence in multicomponent reacting gas mixtures is an important mechanism underlying numerous natural phenomena closely related to the study of our space environment. This book develops a new mathematical approach for modelling multicomponent gas turbulence that adequately describes the combined processes of dynamics and heat and mass transfer when chemical kinetics and turbulent mixing are equally important. The developed models include the evolutionary transfer equations for the single-point second correlation moments of turbulent fluctuations of thermohydrodynamical parameters. The phenomenological approach to the closure problem in hydrodynamic equations of mean motion at the level of the first order moments is based on the thermodynamics of irreversible processes and enables defining relationships in a more general form as compared to those conventionally deduced using the mixing path concept. Based on the developed approach, turbulent exchange factors for a planetary upper atmosphere are evaluated, and a turbulent model of a protoplanetary accretion gas-dust disk involving heat and mass transfer and coagulation is also considered. As compared to previously published books on the problem of turbulence, this book deals, for the first time, with the complicated models of reacting gas mixtures. It is intended for graduate and postgraduate students in the fields of fluid gas dynamics, astrophysics, space physics, planetary sciences, and aeronomy, and especially for those dealing with computer modelling of the processes in such natural media. The book may also be of interest to specialists in the relevant fields of ecology, engineering, and material processing.

  15. An evaluation of atomic and molecular mixture rules and group additivity concepts for the estimation of radiation absorption by long-chained, saturated hydrocarbons at vacuum UV and soft X-ray energies

    NASA Astrophysics Data System (ADS)

    Au, Jennifer W.; Cooper, Glyn; Burton, Gordon R.; Brion, C. E.

    1994-10-01

    The feasibility of using atomic and molecular mixture rules as well as group additivity concepts for predicting valence shell photoabsorption oscillator strengths (cross sections) for long-chained alkane molecules has been investigated over a wide energy range from 18 to 220 eV. The predictions are discussed with reference to recently reported experimental measurements (Chem. Phys. 173 (1993) 209) for normal alkanes, C nH 2 n+2 ( n=1-8). Atomic mixture rules based on either theoretical or experimental atomic oscillator strength sums are found to be unsatisfactory, giving very large errors at most photon energies. A wide range of molecular mixture rules based on linear combinations of measured oscillator strength values for small 'component' alkane molecules and molecular hydrogen have also been evaluated. Although good agreement with experiment is obtained with some linear combinations, many others result in substantial errors. Molecular mixture rules constructed using oscillator strength for larger component alkanes generally give better estimates of the experimentally measured data; however, since no other a priori physical or chemical reasons can be advanced for any particular choice of molecular mixture rule, this procedure is unsatisfactory for general application. In contrast, a group additivity procedure based on oscillator strength estimates for the methylene (CH 2) and methyl (CH 3) alkane group fragments, derived entirely from the photoabsorption measurements for lower alkanes, provides excellent agreement with the measured oscillator strengths for C 8H 18 over the entire energy range studied (18-220 eV). The absolute photoabsorption group oscillator strengths derived for the CH 2 and CH 3 fragments should be applicable to assessing the contributions from saturated hydrocarbon groupings to vacuum UV and soft X-ray absorption in larger chemical and biochemical systems.

  16. Determination of oxygen and nitrogen derivatives of polycyclic aromatic hydrocarbons in fractions of asphalt mixtures using liquid chromatography coupled to mass spectrometry with atmospheric pressure chemical ionization.

    PubMed

    Nascimento, Paulo Cicero; Gobo, Luciana Assis; Bohrer, Denise; Carvalho, Leandro Machado; Cravo, Margareth Coutinho; Leite, Leni Figueiredo Mathias

    2015-12-01

    Liquid chromatography coupled to mass spectrometry with atmospheric pressure chemical ionization was used for the determination of polycyclic aromatic hydrocarbon derivatives, the oxygenated polycyclic aromatic hydrocarbons and nitrated polycyclic aromatic hydrocarbons, formed in asphalt fractions. Two different methods have been developed for the determination of five oxygenated and seven nitrated polycyclic aromatic hydrocarbons that are characterized by having two or more condensed aromatic rings and present mutagenic and carcinogenic properties. The parameters of the atmospheric pressure chemical ionization interface were optimized to obtain the highest possible sensitivity for all compounds. The detection limits of the methods ranged from 0.1 to 57.3 μg/L for nitrated and from 0.1 to 6.6 μg/L for oxygenated derivatives. The limits of quantification were in the range of 4.6-191 μg/L for nitrated and 0.3-8.9 μg/L for oxygenated derivatives. The methods were validated against a diesel particulate extract standard reference material (National Institute of Standards and Technology SRM 1975), and the obtained concentrations (two nitrated derivatives) agreed with the certified values. The methods were applied in the analysis of asphalt samples after their fractionation into asphaltenes and maltenes, according to American Society for Testing and Material D4124, where the maltenic fraction was further separated into its basic, acidic, and neutral parts following the method of Green. Only two nitrated derivatives were found in the asphalt sample, quinoline and 2-nitrofluorene, with concentrations of 9.26 and 2146 mg/kg, respectively, whereas no oxygenated derivatives were detected.

  17. Bioaccumulation of petroleum hydrocarbons in fiddler crabs (Uca minax) exposed to weathered MC-252 crude oil alone and in mixture with an oil dispersant.

    PubMed

    Chase, Darcy A; Edwards, Donn S; Qin, Guangqiu; Wages, Mike R; Willming, Morgan M; Anderson, Todd A; Maul, Jonathan D

    2013-02-01

    The Deepwater Horizon accident in the Gulf of Mexico resulted in a sustained release of crude oil, and weathered oil was reported to have washed onto shorelines and marshes along the Gulf coast. One strategy to minimize effects of tarballs, slicks, and oil sheen, and subsequent risk to nearshore ecosystem resources was to use oil dispersants (primarily Corexit® 9500) at offshore surface and deepwater locations. Data have been generated reporting how Corexit® 9500 and other dispersants may alter the acute toxicity of crude oil (Louisiana sweet crude) to marine organisms. However, it remains unknown how oil dispersants may influence bioaccumulation of petroleum hydrocarbons in nearshore crustaceans. We compare bioaccumulation of petroleum hydrocarbons in fiddler crabs (Uca minax) from exposures to the water accommodated fraction (WAF) of weathered Mississippi Canyon 252 oil (~30 d post spill) and chemically-enhanced WAF when mixed with Corexit® EC9500A. Whole body total petroleum hydrocarbon (TPH) concentrations were greater than background for both treatments after 6h of exposure and reached steady state at 96 h. The modeled TPH uptake rate was greater for crabs in the oil only treatment (k(u)=2.51 mL/g/h vs. 0.76 mL/g/h). Furthermore, during the uptake phase TPH patterns in tissues varied between oil only and oil+dispersant treatments. Steady state bioaccumulation factors (BAFs) were 19.0 mL/g and 14.1 mL/g for the oil only and oil+Corexit treatments, respectively. These results suggest that the toxicokinetic mechanisms of oil may be dependent on oil dispersion (e.g., smaller droplet sizes). The results also indicate that multiple processes and functional roles of species should be considered for understanding how dispersants influence bioavailability of petroleum hydrocarbons.

  18. Quantum cascade laser investigations of CH4 and C2H2 interconversion in hydrocarbon/H2 gas mixtures during microwave plasma enhanced chemical vapor deposition of diamond

    NASA Astrophysics Data System (ADS)

    Ma, Jie; Cheesman, Andrew; Ashfold, Michael N. R.; Hay, Kenneth G.; Wright, Stephen; Langford, Nigel; Duxbury, Geoffrey; Mankelevich, Yuri A.

    2009-08-01

    CH4 and C2H2 molecules (and their interconversion) in hydrocarbon/rare gas/H2 gas mixtures in a microwave reactor used for plasma enhanced diamond chemical vapor deposition (CVD) have been investigated by line-of-sight infrared absorption spectroscopy in the wavenumber range of 1276.5-1273.1 cm-1 using a quantum cascade laser spectrometer. Parameters explored include process conditions [pressure, input power, source hydrocarbon, rare gas (Ar or Ne), input gas mixing ratio], height (z) above the substrate, and time (t) after addition of hydrocarbon to a pre-existing Ar/H2 plasma. The line integrated absorptions so obtained have been converted to species number densities by reference to the companion two-dimensional (r ,z) modeling of the CVD reactor described in Mankelevich et al. [J. Appl. Phys. 104, 113304 (2008)]. The gas temperature distribution within the reactor ensures that the measured absorptions are dominated by CH4 and C2H2 molecules in the cool periphery of the reactor. Nonetheless, the measurements prove to be of enormous value in testing, tensioning, and confirming the model predictions. Under standard process conditions, the study confirms that all hydrocarbon source gases investigated (methane, acetylene, ethane, propyne, propane, and butane) are converted into a mixture dominated by CH4 and C2H2. The interconversion between these two species is highly dependent on the local gas temperature and the H atom number density, and thus on position within the reactor. CH4→C2H2 conversion occurs most efficiently in an annular shell around the central plasma (characterized by 1400

  19. Quantum cascade laser investigations of CH{sub 4} and C{sub 2}H{sub 2} interconversion in hydrocarbon/H{sub 2} gas mixtures during microwave plasma enhanced chemical vapor deposition of diamond

    SciTech Connect

    Ma Jie; Cheesman, Andrew; Ashfold, Michael N. R.; Hay, Kenneth G.; Wright, Stephen; Langford, Nigel; Duxbury, Geoffrey; Mankelevich, Yuri A.

    2009-08-01

    CH{sub 4} and C{sub 2}H{sub 2} molecules (and their interconversion) in hydrocarbon/rare gas/H{sub 2} gas mixtures in a microwave reactor used for plasma enhanced diamond chemical vapor deposition (CVD) have been investigated by line-of-sight infrared absorption spectroscopy in the wavenumber range of 1276.5-1273.1 cm{sup -1} using a quantum cascade laser spectrometer. Parameters explored include process conditions [pressure, input power, source hydrocarbon, rare gas (Ar or Ne), input gas mixing ratio], height (z) above the substrate, and time (t) after addition of hydrocarbon to a pre-existing Ar/H{sub 2} plasma. The line integrated absorptions so obtained have been converted to species number densities by reference to the companion two-dimensional (r,z) modeling of the CVD reactor described in Mankelevich et al. [J. Appl. Phys. 104, 113304 (2008)]. The gas temperature distribution within the reactor ensures that the measured absorptions are dominated by CH{sub 4} and C{sub 2}H{sub 2} molecules in the cool periphery of the reactor. Nonetheless, the measurements prove to be of enormous value in testing, tensioning, and confirming the model predictions. Under standard process conditions, the study confirms that all hydrocarbon source gases investigated (methane, acetylene, ethane, propyne, propane, and butane) are converted into a mixture dominated by CH{sub 4} and C{sub 2}H{sub 2}. The interconversion between these two species is highly dependent on the local gas temperature and the H atom number density, and thus on position within the reactor. CH{sub 4}->C{sub 2}H{sub 2} conversion occurs most efficiently in an annular shell around the central plasma (characterized by 1400CH{sub 4} is favored in the more distant regions where T{sub gas}<1400 K. Analysis of the multistep interconversion mechanism reveals substantial net consumption of H atoms accompanying the CH{sub 4}->C{sub 2}H{sub 2

  20. [Method of infrared spectrum analysis of hydrocarbon mixed gas based on multilevel and SVM-subset].

    PubMed

    Bai, Peng; Xie, Wen-Jun; Liu, Jun-Hua

    2008-02-01

    The hydrocarbon mixed gas was characterized by multi-component and varied density. In order to deal with the difficulties that can not be actually solved with mass mixture gas spectrum data samples, 15 kinds of subset patterns were determined on the basis of investigations and studies, which needed 5 500 spectrum data samples for training and testing. On the basis of this, a method of hydrocarbon mixed gas infrared spectrum analysis based on 2-levels and 15 SVM-subsets was proposed in the light of the idea of working pattern recognition --> mixture gas analysis --> the final result output. In order to solve the problem of new subset working pattern, the SVM online categorization algorithm based on spectrum data relational rule was used. The experimental results show that the component concentration maximal deviation is 0.41% and the maximal average deviation is 0.04%. The method can be used in other mixture gas infrared spectrum analyses, and has the theoretic and application value.

  1. Determination of polycyclic aromatic hydrocarbons in fractions in asphalt mixtures using liquid chromatography coupled to mass spectrometry with atmospheric pressure chemical ionization.

    PubMed

    Nascimento, Paulo Cicero; Gobo, Luciana Assis; Bohrer, Denise; Carvalho, Leandro Machado; Cravo, Margareth Coutinho; Leite, Leni Figueiredo Mathias

    2015-07-01

    An analytical method using liquid chromatography coupled to mass spectrometry with atmospheric pressure chemical ionization for the determination of polycyclic aromatic hydrocarbons in asphalt fractions has been developed. The 14 compounds determined, characterized by having two or more condensed aromatic rings, are expected to be present in asphalt and are considered carcinogenic and mutagenic. The parameters of the atmospheric pressure chemical ionization interface were optimized to obtain the highest possible sensitivity for all of the compounds. The limits of detection ranged from 0.5 to 346.5 μg/L and the limits of quantification ranged from 1.7 to 1550 μg/L. The method was validated against a diesel particulate extract standard reference material (NIST SRM 1975), and the obtained concentrations agreed with the certified values. The method was applied to asphalt samples after its fractionation according to ASTM D4124 and the method of Green. The concentrations of the seven polycyclic aromatic hydrocarbons quantified in the sample ranged from 0.86 mg/kg for benzo[ghi]perylene to 98.32 mg/kg for fluorene.

  2. Novel anisole mixture and gasoline containing the same

    DOEpatents

    Singerman, Gary M.

    1982-01-26

    A novel anisole mixture containing anisole and a mixture of alkyl anisoles and liquid hydrocarbon fuels containing said novel anisole mixture in an amount sufficient to increase the octane number of said liquid fuel composition.

  3. Bundles of aligned carbon nanotubes obtained by the pyrolysis of ferrocene hydrocarbon mixtures: role of the metal nanoparticles produced in situ

    NASA Astrophysics Data System (ADS)

    Satishkumar, B. C.; Govindaraj, A.; Rao, C. N. R.

    1999-07-01

    Aligned nanotube bundles have been produced by the pyrolysis of ferrocene along with methane, acetylene or butane. Ferrocene-acetylene mixtures are found to be ideal for the production of compact aligned nanotube bundles. The nanotube bundles are associated with iron nanoparticles of diameters in the range 2-13 nm. These nanoparticles are ferromagnetic, showing low saturation magnetization compared to bulk iron. The ferromagnetism of the transition metal nanoparticles is likely to be responsible for the alignment of the nanotubes.

  4. A novel spectral resolution and simultaneous determination of multicomponent mixture of Vitamins B1, B6, B12, Benfotiamine and Diclofenac in tablets and capsules by derivative and MCR-ALS.

    PubMed

    Hegazy, Maha A; Abdelwahab, Nada S; Fayed, Ahmed S

    2015-04-05

    A novel method was developed for spectral resolution and further determination of five-component mixture including Vitamin B complex (B1, B6, B12 and Benfotiamine) along with the commonly co-formulated Diclofenac. The method is simple, sensitive, precise and could efficiently determine the five components by a complementary application of two different techniques. The first is univariate second derivative method that was successfully applied for determination of Vitamin B12. The second is Multivariate Curve Resolution using the Alternating Least Squares method (MCR-ALS) by which an efficient resolution and quantitation of the quaternary spectrally overlapped Vitamin B1, Vitamin B6, Benfotiamine and Diclofenac sodium were achieved. The effect of different constraints was studied and the correlation between the true spectra and the estimated spectral profiles were found to be 0.9998, 0.9983, 0.9993 and 0.9933 for B1, B6, Benfotiamine and Diclofenac, respectively. All components were successfully determined in tablets and capsules and the results were compared to HPLC methods and they were found to be statistically non-significant.

  5. A novel spectral resolution and simultaneous determination of multicomponent mixture of Vitamins B1, B6, B12, Benfotiamine and Diclofenac in tablets and capsules by derivative and MCR-ALS

    NASA Astrophysics Data System (ADS)

    Hegazy, Maha A.; Abdelwahab, Nada S.; Fayed, Ahmed S.

    2015-04-01

    A novel method was developed for spectral resolution and further determination of five-component mixture including Vitamin B complex (B1, B6, B12 and Benfotiamine) along with the commonly co-formulated Diclofenac. The method is simple, sensitive, precise and could efficiently determine the five components by a complementary application of two different techniques. The first is univariate second derivative method that was successfully applied for determination of Vitamin B12. The second is Multivariate Curve Resolution using the Alternating Least Squares method (MCR-ALS) by which an efficient resolution and quantitation of the quaternary spectrally overlapped Vitamin B1, Vitamin B6, Benfotiamine and Diclofenac sodium were achieved. The effect of different constraints was studied and the correlation between the true spectra and the estimated spectral profiles were found to be 0.9998, 0.9983, 0.9993 and 0.9933 for B1, B6, Benfotiamine and Diclofenac, respectively. All components were successfully determined in tablets and capsules and the results were compared to HPLC methods and they were found to be statistically non-significant.

  6. Multiphase, multicomponent phase behavior prediction

    NASA Astrophysics Data System (ADS)

    Dadmohammadi, Younas

    Accurate prediction of phase behavior of fluid mixtures in the chemical industry is essential for designing and operating a multitude of processes. Reliable generalized predictions of phase equilibrium properties, such as pressure, temperature, and phase compositions offer an attractive alternative to costly and time consuming experimental measurements. The main purpose of this work was to assess the efficacy of recently generalized activity coefficient models based on binary experimental data to (a) predict binary and ternary vapor-liquid equilibrium systems, and (b) characterize liquid-liquid equilibrium systems. These studies were completed using a diverse binary VLE database consisting of 916 binary and 86 ternary systems involving 140 compounds belonging to 31 chemical classes. Specifically the following tasks were undertaken: First, a comprehensive assessment of the two common approaches (gamma-phi (gamma-ϕ) and phi-phi (ϕ-ϕ)) used for determining the phase behavior of vapor-liquid equilibrium systems is presented. Both the representation and predictive capabilities of these two approaches were examined, as delineated form internal and external consistency tests of 916 binary systems. For the purpose, the universal quasi-chemical (UNIQUAC) model and the Peng-Robinson (PR) equation of state (EOS) were used in this assessment. Second, the efficacy of recently developed generalized UNIQUAC and the nonrandom two-liquid (NRTL) for predicting multicomponent VLE systems were investigated. Third, the abilities of recently modified NRTL model (mNRTL2 and mNRTL1) to characterize liquid-liquid equilibria (LLE) phase conditions and attributes, including phase stability, miscibility, and consolute point coordinates, were assessed. The results of this work indicate that the ϕ-ϕ approach represents the binary VLE systems considered within three times the error of the gamma-ϕ approach. A similar trend was observed for the for the generalized model predictions using

  7. Formation of Titania-Silica Mixed Oxides in Solvent Mixtures and Their Influences for the Photocatalytic CO2 Conversion to Hydrocarbon.

    PubMed

    Parayil, Sreenivasan Koliyat; Razzaq, Abdul; In, Su-Il

    2015-09-01

    TiO2-SiO2 mixed oxide photocatalyst materials responsive to simulated solar light illumination have been synthesized by sol-gel method in various polar and nonpolar organic solvent mixtures. The photocatalysts were characterized by numerous experimental techniques and investigated for the photocatalytic conversion of CO2 to CH4. The TiO2-SiO2 mixed oxide photocatalysts prepared in the presence of nonpolar aromatic solvents such as xylene, toluene or benzene along with ethanol show high surface area, huge mesoporosity and enormous pore volume compared to the materials conventionally synthesized in a mixture of ethanol and hexane. The TiO2-SiO2 mixed oxide photocatalyst prepared in benzene along with ethanol yields 21.0 ppm g(-1) h(-1) of methane production; however the material synthesized in hexane shows negligible amount of methane production under simulated solar light irradiation. These results indicate that aromatic nonpolar solvents can tune the textural properties of photocatalysts compared to non-polar aliphatic solvents.

  8. Combustion and micro-explosion of multicomponent droplets

    SciTech Connect

    Wang, C.H.

    1983-01-01

    An experimental investigation of the gasification, combustion, and micro-explosion of droplets of miscible multicomponent fuel mixtures and water/oil emulsions in hot, oxidizing, pressurized environments is described. The experiment involves generating a stream of droplets of uniform and controllable size, spacing, and velocity by the ink-jet printing technique, injecting them into the continuously flowing combustion environment produced by a flat-flame burner, and examining the subsequent combustion processes using high-speed photography. Results show that the gasification mechanism of miscible multicomponent droplets consist of an initial phase of transient adjustment of the droplet surface layer such that it becomes more concentrated with the less volatile component, and a second phase of liquid-phase-diffusion-limited steady-state combustion with the fractional gasification rate of the constituents being equal to their respective initial mass fractions in the mixture. Micro-explosion of miscible multicomponent droplets is found to be favored with an unstable droplet generation mode, with increasing the system pressure, and with light alcohol addition. The internal bubble growth process is a relatively slow one, occupying about 10% of the droplet lifetime. Micro-explosion of water/oil emulsion droplets occurs under both normal and high pressure environments. Results also show that prior to the onset of micro-explosion in the nominally opaque droplet becomes transparent, indicating deterioration of the emulsion structure. Results and insights on the ignition, extinction, and soot formation characteristics are also documented.

  9. Inhalation Cancer Risk Associated with Exposure to Complex Polycyclic Aromatic Hydrocarbon Mixtures in an Electronic Waste and Urban Area in South China

    PubMed Central

    Wang, Jing; Chen, Shejun; Tian, Mi; Zheng, Xiaobo; Gonzales, Leah; Ohura, Takeshi; Mai, Bixian; Simonich, Staci L. Massey

    2012-01-01

    Atmospheric particulate matter samples were collected from May 2010 to April 2011 in a rural e-waste area and in Guangzhou, South China, to estimate the lifetime inhalation cancer risk from exposure to parent polycyclic aromatic hydrocarbons (PAHs), high molecular weight PAHs (MW 302 PAHs), and halogenated PAHs (HPAHs). Seasonal variations in the PAH concentrations and profile within and between the e-waste and urban areas indicated different PAH sources in the two areas. Benzo[b]fluoranthene, BaP, dibenz[ah]anthracene, and dibenzo[al]pyrene made the most significant contribution to the inhalation cancer risk. MW 302 PAHs accounting for 18.0% of the total cancer risk in the e-waste area and 13.6% in the urban area, while HPAHs made a minor contribution (< 0.1%) in both the areas. The number of lifetime excess lung cancers due to exposure to parent PAHs, MW 302 PAHs, and HPAHs ranged from 15.1 to 1198 per million people in the e-waste area and from 9.3 to 737 per million people in Guangzhou. PAH exposure accounted for 0.02 to 1.94% of the total lung cancer cases in Guangzhou. On average, the inhalation cancer risk in the e-waste area was 1.6 times higher than in the urban area. The e-waste dismantling activities in South China led to higher inhalation cancer risk due to PAH exposure than the urban area. PMID:22913732

  10. Soil cleanup by in-situ surfactant flushing. VIII. Reclamation of multicomponent contaminated sodium dodecylsulfate solutions in surfactant flushing

    SciTech Connect

    Underwood, J.L.; Debelak, K.A.; Wilson, D.J.

    1995-06-01

    Solvent extraction with hexane has been studied for use in reclaiming contaminated surfactant solutions for reuse in remediation of hazardous sites. The hexane flow rate, sodium dodecylsulfate (SDS) concentration, and contaminant mixture were varied to determine their effects on the removal of multicomponent mixtures of phenanthrene, naphthalene, and biphenyl.

  11. Radical scavengers from heavy hydrocarbons

    SciTech Connect

    Kubo, Junichi

    1996-10-01

    The hydrogen-donating properties of some hydrocarbons form the basis for processes such as coal liquefaction and heavy oil upgrading. However, these hydrocarbons have seldom been used for other purposes, because their potential applications have not been well recognized. Research has indicated that these hydrogen-donating hydrocarbons can be used in important reactions as radical scavengers and have properties particular to those of pure hydrocarbons without functional groups containing heteroatoms. Over years of study researchers have found that pure hydrocarbons with radical-scavenging effects nearly as high as those in conventional hindered phenolic antioxidants can be produced from petroleum, and these hydrogen-donating hydrocarbons exhibit such effects even in oxidative atmospheres (i.e., they function as antioxidants). He has also shown that these mixtures have some properties particular to pure hydrocarbons without functional groups containing heteroatoms, and they`ve seen that a mechanism based on the steric effects appears when these hydrocarbons are used in heavy oil hydroprocessing. Hydrogen-donating hydrocarbons should be a viable resource in many applications. In this article, he presents radical-scavenging abilities, characteristics as pure hydrocarbons, and applications on the basis of the studies.

  12. A generalized procedure for the prediction of multicomponent adsorption equilibria

    DOE PAGES

    Ladshaw, Austin; Yiacoumi, Sotira; Tsouris, Costas

    2015-01-01

    Prediction of multicomponent adsorption equilibria has been investigated for several decades. While there are theories available to predict the adsorption behavior of ideal mixtures, there are few purely predictive theories to account for nonidealities in real systems. Most models available for dealing with nonidealities contain interaction parameters that must be obtained through correlation with binary-mixture data. However, as the number of components in a system grows, the number of parameters needed to be obtained increases exponentially. Here, a generalized procedure is proposed, as an extension of the predictive real adsorbed solution theory, for determining the parameters of any activity model,more » for any number of components, without correlation. This procedure is then combined with the adsorbed solution theory to predict the adsorption behavior of mixtures. As this method can be applied to any isotherm model and any activity model, it is referred to as the generalized predictive adsorbed solution theory.« less

  13. A generalized procedure for the prediction of multicomponent adsorption equilibria

    SciTech Connect

    Ladshaw, Austin; Yiacoumi, Sotira; Tsouris, Costas

    2015-01-01

    Prediction of multicomponent adsorption equilibria has been investigated for several decades. While there are theories available to predict the adsorption behavior of ideal mixtures, there are few purely predictive theories to account for nonidealities in real systems. Most models available for dealing with nonidealities contain interaction parameters that must be obtained through correlation with binary-mixture data. However, as the number of components in a system grows, the number of parameters needed to be obtained increases exponentially. Here, a generalized procedure is proposed, as an extension of the predictive real adsorbed solution theory, for determining the parameters of any activity model, for any number of components, without correlation. This procedure is then combined with the adsorbed solution theory to predict the adsorption behavior of mixtures. As this method can be applied to any isotherm model and any activity model, it is referred to as the generalized predictive adsorbed solution theory.

  14. Membrane separation of hydrocarbons

    DOEpatents

    Chang, Y. Alice; Kulkarni, Sudhir S.; Funk, Edward W.

    1986-01-01

    Mixtures of heavy oils and light hydrocarbons may be separated by passing the mixture through a polymeric membrane. The membrane which is utilized to effect the separation comprises a polymer which is capable of maintaining its integrity in the presence of hydrocarbon compounds and which has been modified by being subjected to the action of a sulfonating agent. Sulfonating agents which may be employed will include fuming sulfuric acid, chlorosulfonic acid, sulfur trioxide, etc., the surface or bulk modified polymer will contain a degree of sulfonation ranging from about 15 to about 50%. The separation process is effected at temperatures ranging from about ambient to about 100.degree. C. and pressures ranging from about 50 to about 1000 psig.

  15. Scaled equation of state for multi-component fluids

    NASA Astrophysics Data System (ADS)

    Belyakov, M. Yu.; Gorodetskii, E. E.; Kulikov, V. D.; Voronov, V. P.; Grigoriev, B. A.

    2014-12-01

    Theory model based on the concept of so-called "complete scaling" has been extensively developed for multicomponent mixtures. As a result, the equation of state (EOS) for near-critical mixture with given composition has been formulated. To verify the validity of the obtained EOS, it was applied for the description of thermodynamic properties of the fourteen-component mixture modeling a natural gas condensate. The mixture has been studied in our laboratory by the adiabatic calorimetry method. The measurements of the pressure, the derivative (∂ P / ∂ T) ρ, x and heat capacity Cρ,x were carried out for nine isochores in rather wide range of pressures and temperatures including the near-critical region. It has been demonstrated that the proposed EOS describes adequately the experimental data in one- and two-phase region of the mixture with the sufficiently high accuracy. In addition, the analysis of experimental data by means of developed EOS enables us to calculate the dew-bubble curves of the mixture as well as to determine the mixture critical parameters.

  16. Multi-Component Dark Matter

    SciTech Connect

    Zurek, Kathryn M.

    2008-11-01

    We explore multi-component dark matter models where the dark sector consists of multiple stable states with different mass scales, and dark forces coupling these states further enrich the dynamics. The multi-component nature of the dark matter naturally arises in supersymmetric models, where both R parity and an additional symmetry, such as a Z{sub 2}, is preserved. We focus on a particular model where the heavier component of dark matter carries lepton number and annihilates mostly to leptons. The heavier component, which is essentially a sterile neutrino, naturally explains the PAMELA, ATIC and synchrotron signals, without an excess in antiprotons which typically mars other models of weak scale dark matter. The lighter component, which may have a mass from a GeV to a TeV, may explain the DAMA signal, and may be visible in low threshold runs of CDMS and XENON, which search for light dark matter.

  17. Multicomponent reactions in nucleoside chemistry

    PubMed Central

    Buchowicz, Włodzimierz

    2014-01-01

    Summary This review covers sixty original publications dealing with the application of multicomponent reactions (MCRs) in the synthesis of novel nucleoside analogs. The reported approaches were employed for modifications of the parent nucleoside core or for de novo construction of a nucleoside scaffold from non-nucleoside substrates. The cited references are grouped according to the usually recognized types of the MCRs. Biochemical properties of the novel nucleoside analogs are also presented (if provided by the authors). PMID:25161730

  18. Alfven wave dispersion behavior in single- and multicomponent plasmas

    SciTech Connect

    Rahbarnia, K.; Grulke, O.; Klinger, T.; Ullrich, S.; Sauer, K.

    2010-03-15

    Dispersion relations of driven Alfven waves (AWs) are measured in single- and multicomponent plasmas consisting of mixtures of argon, helium, and oxygen in a magnetized linear cylindrical plasma device VINETA [C. Franck, O. Grulke, and T. Klinger, Phys. Plasmas 9, 3254 (2002)]. The decomposition of the measured three-dimensional magnetic field fluctuations and the corresponding parallel current pattern reveals that the wave field is a superposition of L- and R-wave components. The dispersion relation measurements agree well with calculations based on a multifluid Hall-magnetohydrodynamic model if the plasma resistivity is correctly taken into account.

  19. Multi-Component Diffusion with Application To Computational Aerothermodynamics

    NASA Technical Reports Server (NTRS)

    Sutton, Kenneth; Gnoffo, Peter A.

    1998-01-01

    The accuracy and complexity of solving multicomponent gaseous diffusion using the detailed multicomponent equations, the Stefan-Maxwell equations, and two commonly used approximate equations have been examined in a two part study. Part I examined the equations in a basic study with specified inputs in which the results are applicable for many applications. Part II addressed the application of the equations in the Langley Aerothermodynamic Upwind Relaxation Algorithm (LAURA) computational code for high-speed entries in Earth's atmosphere. The results showed that the presented iterative scheme for solving the Stefan-Maxwell equations is an accurate and effective method as compared with solutions of the detailed equations. In general, good accuracy with the approximate equations cannot be guaranteed for a species or all species in a multi-component mixture. 'Corrected' forms of the approximate equations that ensured the diffusion mass fluxes sum to zero, as required, were more accurate than the uncorrected forms. Good accuracy, as compared with the Stefan- Maxwell results, were obtained with the 'corrected' approximate equations in defining the heating rates for the three Earth entries considered in Part II.

  20. Prediction of flame velocities of hydrocarbon flames

    NASA Technical Reports Server (NTRS)

    Dugger, Gordon L; Simon, Dorothy M

    1954-01-01

    The laminar-flame-velocity data previously reported by the Lewis Laboratory are surveyed with respect to the correspondence between experimental flame velocities and values predicted by semitheoretical and empirical methods. The combustible mixture variables covered are hydrocarbon structure (56 hydrocarbons), equivalence ratio of fuel-air mixture, mole fraction of oxygen in the primary oxygen-nitrogen mixture (0.17 to 0.50), and initial mixture temperature (200 degrees to 615 degrees k). The semitheoretical method of prediction considered are based on three approximate theoretical equations for flame velocity: the Semenov equation, the Tanford-Pease equation, and the Manson equation.

  1. Effect of composition on the density of multi-component molten nitrate salts.

    SciTech Connect

    Bradshaw, Robert W.

    2009-12-01

    The density of molten nitrate salts was measured to determine the effects of the constituents on the density of multi-component mixtures. The molten salts consisted of various proportions of the nitrates of potassium, sodium, lithium and calcium. Density measurements ere performed using an Archimedean method and the results were compared to data reported in the literature for the individual constituent salts or simple combinations, such as the binary Solar Salt mixture of NaNO3 and KNO3. The addition of calcium nitrate generally ncreased density, relative to potassium nitrate or sodium nitrate, while lithium nitrate decreased density. The temperature dependence of density is described by a linear equation regardless of composition. The molar volume, and thereby, density of multi-component mixtures an be calculated as a function of temperature using a linear additivity rule based on the properties of the individual constituents.

  2. Mercury-free PVT apparatus for thermophysical property analyses of hydrocarbon reservoir fluids

    SciTech Connect

    Lansangan, R.M.; Lievois, J.S.

    1992-08-31

    Typical reservoir fluid analyses of complex, multicomponent hydrocarbon mixtures include the volumetric properties, isothermal compressibility, thermal expansivity, equilibrium ratios, saturation pressure, viscosities, etc. These parameters are collectively referred to as PVT properties, an acronym for the primary state variables; pressure, volume, and temperature. The reservoir engineer incorporates this information together with the porous media description in performing material balance calculations. These calculations lead to the determination (estimation) of the initial hydrocarbon in-place, the future reservoir performance, the optimal production scheme, and the ultimate hydrocarbon recovery. About four years ago, Ruska Instrument Corporation embarked on a project to develop an apparatus designed to measure PVT properties that operates free of mercury. The result of this endeavor is the 2370 Hg-Free PVT system which has been in the market for the last three years. The 2370 has evolved from the prototype unit to its present configuration which is described briefly in this report. The 2370 system, although developed as a system-engineered apparatus based on existing technology, has not been exempt from this burden-of-proof Namely, the performance of the apparatus under routine test conditions with real reservoir fluids. This report summarizes the results of the performance and applications testing of the 2370 Hg-Free PVT system. Density measurements were conducted on a pure fluid. The results were compared against literature values and the prediction of an equation of state. Routine reservoir fluid analyses were conducted with a black oil and a retrograde condensate gas mixtures. Limited comparison of the results were performed based on the same tests performed on a conventional mercury-based PVT apparatus. The results of these tests are included in this report.

  3. Problems in Catalytic Oxidation of Hydrocarbons and Detailed Simulation of Combustion Processes

    NASA Astrophysics Data System (ADS)

    Xin, Yuxuan

    This dissertation research consists of two parts, with Part I on the kinetics of catalytic oxidation of hydrocarbons and Part II on aspects on the detailed simulation of combustion processes. In Part I, the catalytic oxidation of C1--C3 hydrocarbons, namely methane, ethane, propane and ethylene, was investigated for lean hydrocarbon-air mixtures over an unsupported Pd-based catalyst, from 600 to 800 K and under atmospheric pressure. In Chapter 2, the experimental facility of wire microcalorimetry and simulation configuration were described in details. In Chapter 3 and 4, the oxidation rate of C1--C 3 hydrocarbons is demonstrated to be determined by the dissociative adsorption of hydrocarbons. A detailed surface kinetics model is proposed with deriving the rate coefficient of hydrocarbon dissociative adsorption from the wire microcalorimetry data. In Part II, four fundamental studies were conducted through detailed combustion simulations. In Chapter 5, self-accelerating hydrogen-air flames are studied via two-dimensional detailed numerical simulation (DNS). The increase in the global flame velocity is shown to be caused by the increase of flame surface area, and the fractal structure of the flame front is demonstrated by the box-counting method. In Chapter 6, skeletal reaction models for butane combustion are derived by using directed relation graph (DRG) and DRG-aided sensitivity analysis (DRGASA), and uncertainty minimization by polynomial chaos expansion (MUM-PCE) mothodes. The dependence of model uncertainty is subjected to the completeness of the model. In Chapter 7, a systematic strategy is proposed to reduce the cost of the multicomponent diffusion model by accurately accounting for the species whose diffusivity is important to the global responses of the combustion systems, and approximating those of less importance by the mixture-averaged model. The reduced model is validated in an n-heptane mechanism with 88 species. In Chapter 8, the influence of Soret

  4. Calculation of vapor-liquid equilibrium and PVTx properties of geological fluid system with SAFT-LJ EOS including multi-polar contribution. Part III. Extension to water-light hydrocarbons systems

    NASA Astrophysics Data System (ADS)

    Sun, Rui; Lai, Shaocong; Dubessy, Jean

    2014-01-01

    The SAFT-LJ EOS improved by Sun and Dubessy (2010, 2012) is extended to water-light hydrocarbon systems. Light hydrocarbons (including CH4, C2H6, C3H8 and nC4H10) are modeled as chain molecules without multi-polar moments. The contributions of the shape of molecules and main intermolecular interactions existing in water-light hydrocarbon systems (including repulsive and attractive forces between Lennard-Jones segments, the hydrogen-bonding force and the multi-polar interaction between water molecules) to the residual Helmholtz energy were accounted for by this EOS. The adjustable parameters for the interactions of H2O-CH4, H2O-C2H6, H2O-C3H8, and H2O-nC4H10 pairs were evaluated from mutual solubility data of binary water-hydrocarbon systems at vapor-liquid equilibria. Comparison with the experimental data shows this SAFT-LJ EOS can represent well vapor-liquid (and liquid-liquid) equilibria of binary water-light hydrocarbon systems over a wide P-T range. The accuracy of this EOS for mutual solubilities of methane, ethane, propane and water is within the experimental uncertainty generally. Moreover, the model is able to accurately predict the vapor-liquid equilibria and PVTx properties of multi-component systems composed of water, light hydrocarbon as well as CO2. As we know, this EOS is the first one allowing quantitative calculation of the mutual solubilities of water and light hydrocarbons over a wide P-T range among SAFT-type EOSs. This work indicates that the molecular-based EOS combined with conventional mixing rule can well describe the thermodynamic behavior of highly non-ideal systems such as water-light hydrocarbons mixtures except in the critical region for which long range density fluctuations cannot be taken into account by this analytical model.

  5. A Multicomponent Animal Virus Isolated from Mosquitoes.

    PubMed

    Ladner, Jason T; Wiley, Michael R; Beitzel, Brett; Auguste, Albert J; Dupuis, Alan P; Lindquist, Michael E; Sibley, Samuel D; Kota, Krishna P; Fetterer, David; Eastwood, Gillian; Kimmel, David; Prieto, Karla; Guzman, Hilda; Aliota, Matthew T; Reyes, Daniel; Brueggemann, Ernst E; St John, Lena; Hyeroba, David; Lauck, Michael; Friedrich, Thomas C; O'Connor, David H; Gestole, Marie C; Cazares, Lisa H; Popov, Vsevolod L; Castro-Llanos, Fanny; Kochel, Tadeusz J; Kenny, Tara; White, Bailey; Ward, Michael D; Loaiza, Jose R; Goldberg, Tony L; Weaver, Scott C; Kramer, Laura D; Tesh, Robert B; Palacios, Gustavo

    2016-09-14

    RNA viruses exhibit a variety of genome organization strategies, including multicomponent genomes in which each segment is packaged separately. Although multicomponent genomes are common among viruses infecting plants and fungi, their prevalence among those infecting animals remains unclear. We characterize a multicomponent RNA virus isolated from mosquitoes, designated Guaico Culex virus (GCXV). GCXV belongs to a diverse clade of segmented viruses (Jingmenvirus) related to the prototypically unsegmented Flaviviridae. The GCXV genome comprises five segments, each of which appears to be separately packaged. The smallest segment is not required for replication, and its presence is variable in natural infections. We also describe a variant of Jingmen tick virus, another Jingmenvirus, sequenced from a Ugandan red colobus monkey, thus expanding the host range of this segmented and likely multicomponent virus group. Collectively, this study provides evidence for the existence of multicomponent animal viruses and their potential relevance for animal and human health.

  6. Photosensitivity phenomena in multicomponent glasses

    NASA Astrophysics Data System (ADS)

    Czachor, K.; Jedrzejewski, K.; Stępień, R.

    2005-09-01

    Low cost, high bandwidth, narrowband and multifunctionality are main targets for new optical devices development. Planar optics is probably the best solution for future telecom long distance and access transmission networks but also for metrology sensing devices. Many different materials can be used for this purpose like PECVD silica, multicomponent glasses or even polymers. Bragg grating inscription in such material is another advantage to achieve narrowband spectral characteristic of device, which is essential in modern systems. The main purpose of presented work was the development in technology and measurement techniques of channels formed on the surface of the glass. Planar couplers and structures that are more complicated can also be made in the same technology in the future. Special multicomponent glasses SiO2-GeO2-B2O3-Na2O-SnO2 with up to 6 %mol of Sn were synthetized and thin rectangular polished plates were prepared. The UV 244 nm 100 mW Coherent argon ion frequency doubled laser was used in our experiments. Surface relief structures similar to the compaction-densification/expansion model of photosensitivity were developed on the glass surface. The optical microscope and alpha-step profiler were used for preliminary tests of photoinduced structures on the glass surface. The ability of the writing possibility in function of Sn content and different laser power levels were analyzed.

  7. Scaled Particle Theory for Multicomponent Hard Sphere Fluids Confined in Random Porous Media.

    PubMed

    Chen, W; Zhao, S L; Holovko, M; Chen, X S; Dong, W

    2016-06-23

    The formulation of scaled particle theory (SPT) is presented for a quite general model of fluids confined in a random porous media, i.e., a multicomponent hard sphere (HS) fluid in a multicomponent hard sphere or a multicomponent overlapping hard sphere (OHS) matrix. The analytical expressions for pressure, Helmholtz free energy, and chemical potential are derived. The thermodynamic consistency of the proposed theory is established. Moreover, we show that there is an isomorphism between the SPT for a multicomponent system and that for a one-component system. Results from grand canonical ensemble Monte Carlo simulations are also presented for a binary HS mixture in a one-component HS or a one-component OHS matrix. The accuracy of various variants derived from the basic SPT formulation is appraised against the simulation results. Scaled particle theory, initially formulated for a bulk HS fluid, has not only provided an analytical tool for calculating thermodynamic properties of HS fluid but also helped to gain very useful insight for elaborating other theoretical approaches such as the fundamental measure theory (FMT). We expect that the general SPT for multicomponent systems developed in this work can contribute to the study of confined fluids in a similar way.

  8. 75 FR 8937 - Development of a Relative Potency Factor (RPF) Approach for Polycyclic Aromatic Hydrocarbon (PAH...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-02-26

    ... AGENCY Development of a Relative Potency Factor (RPF) Approach for Polycyclic Aromatic Hydrocarbon (PAH...) Approach for Polycyclic Aromatic Hydrocarbon (PAH) Mixtures'' (EPA/635/R-08/012A). The draft document was... of a Relative Potency Factor (RPF) Approach for Polycyclic Aromatic Hydrocarbon (PAH) Mixtures''...

  9. Method and apparatus for low temperature destruction of halogenated hydrocarbons

    DOEpatents

    Reagen, William Kevin; Janikowski, Stuart Kevin

    1999-01-01

    A method and apparatus for decomposing halogenated hydrocarbons are provided. The halogenated hydrocarbon is mixed with solvating agents and maintained in a predetermined atmosphere and at a predetermined temperature. The mixture is contacted with recyclable reactive material for chemically reacting with the recyclable material to create dehalogenated hydrocarbons and halogenated inorganic compounds. A feature of the invention is that the process enables low temperature destruction of halogenated hydrocarbons.

  10. Particle Lithography Enables Fabrication of Multicomponent Nanostructures

    PubMed Central

    Lin, Wei-feng; Swartz, Logan A.; Li, Jie-Ren; Liu, Yang; Liu, Gang-yu

    2014-01-01

    Multicomponent nanostructures with individual geometries have attracted much attention because of their potential to carry out multiple functions synergistically. The current work reports a simple method using particle lithography to fabricate multicomponent nanostructures of metals, proteins, and organosiloxane molecules, each with its own geometry. Particle lithography is well-known for its capability to produce arrays of triangular-shaped nanostructures with novel optical properties. This paper extends the capability of particle lithography by combining a particle template in conjunction with surface chemistry to produce multicomponent nanostructures. The advantages and limitations of this approach will also be addressed. PMID:24707328

  11. Enthalpy Diffusion in Multicomponent Flows

    SciTech Connect

    Cook, A W

    2008-11-12

    The enthalpy diffusion flux in the multicomponent energy equation is a well known yet frequently neglected term. It accounts for energy changes, associated with compositional changes, resulting from species diffusion. Enthalpy diffusion is important in flows where significant mixing occurs between species of dissimilar molecular weight. The term plays a critical role in preventing local violations of the entropy condition. In simulations of nonpremixed combustion, omission of the enthalpy flux can lead to anomalous temperature gradients, which may cause mixing regions to exceed ignition conditions. The term can also play a role in generating acoustic noise in turbulent mixing layers. Euler solvers that rely on numerical diffusion to mix fluids cannot accurately predict the temperature in mixed regions. On the other hand, Navier-Stokes solvers that incorporate enthalpy diffusion can provide much more accurate results.

  12. Multi-component assembly casting

    DOEpatents

    James, Allister W.

    2015-10-13

    Multi-component vane segment and method for forming the same. Assembly includes: positioning a pre-formed airfoil component (12) and a preformed shroud heat resistant material (18) in a mold, wherein the airfoil component (12) and the shroud heat resistant material (18) each comprises an interlocking feature (24); preheating the mold; introducing molten structural material (46) into the mold; and solidifying the molten structural material such that it interlocks the pre-formed airfoil component (12) with respect to the preformed shroud heat resistant material (18) and is effective to provide structural support for the shroud heat resistant material (18). Surfaces between the airfoil component (12) and the structural material (46), between the airfoil component (12) and the shroud heat resistant material (18), and between the shroud heat resistant material (18) and the structural material (46) are free of metallurgical bonds.

  13. Mixture Experiments

    SciTech Connect

    Piepel, Gregory F.

    2007-12-01

    A mixture experiment involves combining two or more components in various proportions or amounts and then measuring one or more responses for the resulting end products. Other factors that affect the response(s), such as process variables and/or the total amount of the mixture, may also be studied in the experiment. A mixture experiment design specifies the combinations of mixture components and other experimental factors (if any) to be studied and the response variable(s) to be measured. Mixture experiment data analyses are then used to achieve the desired goals, which may include (i) understanding the effects of components and other factors on the response(s), (ii) identifying components and other factors with significant and nonsignificant effects on the response(s), (iii) developing models for predicting the response(s) as functions of the mixture components and any other factors, and (iv) developing end-products with desired values and uncertainties of the response(s). Given a mixture experiment problem, a practitioner must consider the possible approaches for designing the experiment and analyzing the data, and then select the approach best suited to the problem. Eight possible approaches include 1) component proportions, 2) mathematically independent variables, 3) slack variable, 4) mixture amount, 5) component amounts, 6) mixture process variable, 7) mixture of mixtures, and 8) multi-factor mixture. The article provides an overview of the mixture experiment designs, models, and data analyses for these approaches.

  14. Inhibition of natural gas hydrates in the presence of liquid hydrocarbons forming structure H.

    PubMed

    Seo, Yutaek; Kang, Seong-Pil; Jang, Wonho; Kim, Seonwook

    2010-05-13

    The effects of LMGS (large molecule guest substance) amount on the thermodynamics of natural gas hydrates, as well as structural characteristics of mixed hydrates of LMGS and natural gas, have been studied. The addition of 1.7 wt % neohexane (NH) to water induced inhibition of natural gas hydrates, and this inhibition effect increased with increased addition of NH up to 7.8 wt %. However, the hydrate equilibrium condition changed slightly when the concentration of NH further increased from 7.8 to 14.5 wt %. Investigations on structural characteristics were carried out by analyzing (13)C NMR spectra of mixed hydrates formed from the mixture of natural gas and NH. They indicate that two hydrate structures of II and H coexist simultaneously, and the ratio of structure H to II decreased from 0.97 to 0.43 when the NH concentration decreased from 14.5 to 7.8 wt %. In addition, it was confirmed that ethane, propane, and iso-butane gas molecules do not participate in the formation of structure H and only enclathrated in large cages of structure II. These results indicate the existence of multiple hydrate structures, which must be considered in many industrial applications when mixed hydrates are formed from multicomponent gas mixtures and liquid hydrocarbons.

  15. Slip conditions with wall catalysis and radiation for multicomponent, nonequilibrium gas flow. [for predicting heat transfer to the space shuttle

    NASA Technical Reports Server (NTRS)

    Hendricks, W. L.

    1974-01-01

    The slip conditions for a multicomponent mixture with diffusion, wall-catalyzed atom recombination and thermal radiation are derived, and simplified expressions for engineering applications are presented. The gas mixture may be in chemical nonequilibrium with finite-rate catalytic recombination occurring on the wall. These boundary conditions, which are used for rarefied flow regime flow field calculations, are shown to be necessary for accurate predictions of skin friction and heat transfer coefficients in the rarefied portion of the space shuttle trajectory.

  16. Ozone Modulation/Membrane Introduction Mass Spectrometry for Analysis of Hydrocarbon Pollutants in Air

    NASA Astrophysics Data System (ADS)

    Atkinson, D. B.

    2001-12-01

    mixtures was also observed. Despite this problem, the hydrocarbon signal response can be calibrated and the method can be used for quantitative analysis of volatile hydrocarbon compounds in air samples. This methodology should augment the efficiency of the MIMS approach in online and onsite monitoring of VOC emissions. Bier, M.R., and R.G. Cooks, Membrane Interface for Selective Introduction of Volatile Compounds Directly into The Ionization Chamber of a Mass Spectrometer, Anal. Chem., 59 (4), 597, 1987. Cisper, M.E., C.G. Gill, L.E. Townsend, and P.H. Hemberger, On-Line Detection of Volatile Organic Compounds in Air at Parts-per-Trillion Levels by Membrane Introduction Mass Spectrometry, Anal. Chem., 67 (8), 1413-1417, 1995. Ketola, R.A., M. Ojala, and J. Heikkonen, A Non-linear Asymmetric Error Function-based Least Mean Square Approach for the Analysis of Multicomponent Mass Spectra Measured by Membrane Inlet Mass Spectrometry, Rapid Commun. Mass Spectrom., 13 (8), 654, 1999. Kotiaho, T., and R.G. Cooks, Membrane Introduction Mass Spectrometry in Environmental Analysis, in: J.J. Breen, M. J. Dellarco, (Eds), Pollution in Industrial processes, 126 pp., ACS Symp. Ser., Washington, D.C. 508, 1992.

  17. Impact of multi-component diffusion in turbulent combustion using direct numerical simulations

    DOE PAGES

    Bruno, Claudio; Sankaran, Vaidyanathan; Kolla, Hemanth; ...

    2015-08-28

    This study presents the results of DNS of a partially premixed turbulent syngas/air flame at atmospheric pressure. The objective was to assess the importance and possible effects of molecular transport on flame behavior and structure. To this purpose DNS were performed at with two proprietary DNS codes and with three different molecular diffusion transport models: fully multi-component, mixture averaged, and imposing the Lewis number of all species to be unity.

  18. On the averaging of ratios of specific heats in a multicomponent planetary atmosphere

    NASA Technical Reports Server (NTRS)

    Dubisch, R.

    1974-01-01

    The use of adiabatic relations in the calculation of planetary atmospheres requires knowledge of the ratio of specific heats of a mixture of gases under various pressure and temperature conditions. It is shown that errors introduced by simple averaging of the ratio of specific heats in a multicomponent atmosphere can be roughly 0.4%. Therefore, the gamma-averaging error can become important when integrating through the atmosphere to a large depth.

  19. Multicomponent fuel vaporization at high pressures.

    SciTech Connect

    Torres, D. J.; O'Rourke, P. J.

    2002-01-01

    We extend our multicomponent fuel model to high pressures using a Peng-Robinson equation of state, and implement the model into KIVA-3V. Phase equilibrium is achieved by equating liquid and vapor fugacities. The latent heat of vaporization and fuel enthalpies are also corrected for at high pressures. Numerical simulations of multicomponent evaporation are performed for single droplets for a diesel fuel surrogate at different pressures.

  20. Laser ultrasonic multi-component imaging

    DOEpatents

    Williams, Thomas K [Federal Way, WA; Telschow, Kenneth [Des Moines, WA

    2011-01-25

    Techniques for ultrasonic determination of the interfacial relationship of multi-component systems are discussed. In implementations, a laser energy source may be used to excite a multi-component system including a first component and a second component at least in partial contact with the first component. Vibrations resulting from the excitation may be detected for correlation with a resonance pattern indicating if discontinuity exists at the interface of the first and second components.

  1. Biological enhancement of hydrocarbon extraction

    DOEpatents

    Brigmon, Robin L.; Berry, Christopher J.

    2009-01-06

    A method of microbial enhanced oil recovery for recovering oil from an oil-bearing rock formation is provided. The methodology uses a consortium of bacteria including a mixture of surfactant producing bacteria and non-surfactant enzyme producing bacteria which may release hydrocarbons from bitumen containing sands. The described bioprocess can work with existing petroleum recovery protocols. The consortium microorganisms are also useful for treatment of above oil sands, ground waste tailings, subsurface oil recovery, and similar materials to enhance remediation and/or recovery of additional hydrocarbons from the materials.

  2. Effective binary theory of multi-component nucleation

    SciTech Connect

    Kalikmanov, V. I.

    2015-03-28

    Classical theory of multi-component nucleation [O. Hirschfelder, J. Chem. Phys. 61, 2690 (1974)] belongs to the class of the so-called intractable problems: it requires computational time which is an exponential function of the number of components N. For a number of systems of practical interest with N > 10, the brute-force use of the classical theory becomes virtually impossible and one has to resort to an effective medium approach. We present an effective binary model which captures important physics of multi-component nucleation. The distinction between two effective species is based on the observation that while all N components contribute to the cluster thermodynamic properties, there is only a part of them which trigger the nucleation process. The proposed 2D-theory takes into account adsorption by means of the Gibbs dividing surface formalism and uses statistical mechanical considerations for the treatment of small clusters. Theoretical predictions for binary-, ternary-, and 14-component mixtures are compared with available experimental data and other models.

  3. Dynamics of multicomponent vesicles in a viscous fluid

    SciTech Connect

    Sohn, Jin Sun Tseng, Y-H Li Shuwang Voigt, Axel Lowengrub, John S.

    2010-01-01

    We develop and investigate numerically a thermodynamically consistent model of two-dimensional multicomponent vesicles in an incompressible viscous fluid. The model is derived using an energy variation approach that accounts for different lipid surface phases, the excess energy (line energy) associated with surface phase domain boundaries, bending energy, spontaneous curvature, local inextensibility and fluid flow via the Stokes equations. The equations are high-order (fourth order) nonlinear and nonlocal due to incompressibility of the fluid and the local inextensibility of the vesicle membrane. To solve the equations numerically, we develop a nonstiff, pseudo-spectral boundary integral method that relies on an analysis of the equations at small scales. The algorithm is closely related to that developed very recently by Veerapaneni et al. [81] for homogeneous vesicles although we use a different and more efficient time stepping algorithm and a reformulation of the inextensibility equation. We present simulations of multicomponent vesicles in an initially quiescent fluid and investigate the effect of varying the average surface concentration of an initially unstable mixture of lipid phases. The phases then redistribute and alter the morphology of the vesicle and its dynamics. When an applied shear is introduced, an initially elliptical vesicle tank-treads and attains a steady shape and surface phase distribution. A sufficiently elongated vesicle tumbles and the presence of different surface phases with different bending stiffnesses and spontaneous curvatures yields a complex evolution of the vesicle morphology as the vesicle bends in regions where the bending stiffness and spontaneous curvature are small.

  4. Apparatus for hydrocarbon extraction

    DOEpatents

    Bohnert, George W.; Verhulst, Galen G.

    2013-03-19

    Systems and methods for hydrocarbon extraction from hydrocarbon-containing material. Such systems and methods relate to extracting hydrocarbon from hydrocarbon-containing material employing a non-aqueous extractant. Additionally, such systems and methods relate to recovering and reusing non-aqueous extractant employed for extracting hydrocarbon from hydrocarbon-containing material.

  5. Time-derivative preconditioning method for multicomponent flow

    NASA Astrophysics Data System (ADS)

    Housman, Jeffrey Allen

    A time-derivative preconditioned system of equations suitable for the numerical simulation of single component and multicomponent inviscid flows at all speeds is formulated. The system is shown to be hyperbolic in time and remain well-posed at low Mach numbers, allowing an efficient time marching solution strategy to be utilized from transonic to incompressible flow speeds. For multicomponent flow at low speed, a preconditioned nonconservative discretization scheme is described which preserves pressure and velocity equilibrium across fluid interfaces, handles sharp liquid/gas interfaces with large density ratios, while remaining well-conditioned for time marching methods. The method is then extended to transonic and supersonic flows using a hybrid conservative/nonconservative formulation which retains the pressure/velocity equilibrium property and converges to the correct weak solution when shocks are present. In order to apply the proposed model to complex flow applications, the overset grid methodology is used where the equations are transformed to a nonorthogonal curvilinear coordinate system and discretized on structured body-fitted curvilinear grids. The multicomponent model and its extension to homogeneous multiphase mixtures is discussed and the hyperbolicity of the governing equations is demonstrated. Low Mach number perturbation analysis is then performed on the system of equations and a local time-derivative preconditioning matrix is derived allowing time marching numerical methods to remain efficient at low speeds. Next, a particular time marching numerical method is presented along with three discretization schemes for the convective terms. These include a conservative preconditioned Roe type method, a nonconservative preconditioned Split Coefficient Matrix (SCM) method, and hybrid formulation which combines the conservative and nonconservative schemes using a simple switching function. A characteristic boundary treatment which includes time

  6. Dynamics of multicomponent lipid membranes

    NASA Astrophysics Data System (ADS)

    Camley, Brian Andrew

    We present theoretical and computational descriptions of the dynamics of multicomponent lipid bilayer membranes. These systems are both model systems for "lipid rafts" in cell membranes and interesting physical examples of quasi-two-dimensional fluids. Our chief tool is a continuum simulation that uses a phase field to track the composition of the membrane, and solves the hydrodynamic equations exactly using the appropriate Green's function (Oseen tensor) for the membrane. We apply this simulation to describe the diffusion of domains in phase-separated membranes, the dynamics of domain flickering, and the process of phase separation in lipid membranes. We then derive an analytical theory to describe domain flickering that is consistent with our simulation results, and use this to analyze experimental measurements of membrane domains. Through this method, we measure the membrane viscosity solely from fluorescence microscopy measurements. We study phase separation in quasi-two-dimensional membranes in depth with both simulations and scaling theory, and classify the different scaling regimes and morphologies, which differ from pure two-dimensional fluids. Our results may explain previous inconsistent measurements of the dynamical scaling exponent for phase separation in membranes. We also extend our theory beyond the simplest model, including the possibility that the membrane will be viscoelastic, as well as considering the inertia of the membrane and the fluid surrounding the membrane.

  7. Diclofenac Sodium Loaded Multicomponent Implant

    NASA Astrophysics Data System (ADS)

    Nikkola, Lila; Viitanen, Petrus; Ashammakhi, Nureddin

    2008-02-01

    Earlier we have reported on developing DS releasing bioabsorbable rods for inhibition of osteolysis [l]. Due to their unsatisfactory drug release profiles we assessed the use of sintering technique of enhancement of drug release in the current study. Melt extruded PLGA 80/20 rods were compounded 8 wt-% DS. Some rods were self reinforced (SR) and some of them were sterilized to get three different components with different drug release profiles. Different rods were sintered together with heat and pressure. Three different specimen groups with different construction were studied. Thermal properties were analyzed using differential scanning calorimetry (DSC). Changes of IV were performed with capillary analysis and drug release measurements with UV-Vis spectrophotometer. Mechanical strength were measured two weeks, when disintegration occurred. Release rate consisted of 1) sharp jump start peak, 2) second smoother peak, and 3) third smooth peak. Released DS concentrations reached local therapeutic levels and maintained at that stage for 24-36 days. All DS was released during 50-70 days. The drug release from multicomponent implant was more stable and commenced earlier than from initial rods. Such properties were favored ones. Initial shear strength was 82 MPa and it decreased to 15 MPa. The mechanical bonding was sufficient although the components disintegrated relatively fast. By sintering different PLGA/DS components with different release rates it is possible to construct a truly controlled release implant for bone fixation with anti-inflammatory properties.

  8. Multicomponent Therapeutics of Berberine Alkaloids

    PubMed Central

    Luo, Jiaoyang; Yan, Dan; Yang, Meihua; Dong, Xiaoping; Xiao, Xiaohe

    2013-01-01

    Although berberine alkaloids (BAs) are reported to be with broad-spectrum antibacterial and antiviral activities, the interactions among BAs have not been elucidated. In the present study, methicillin-resistant Staphylococcus aureus (MRSA) was chosen as a model organism, and modified broth microdilution was applied for the determination of the fluorescence absorption values to calculate the anti-MRSA activity of BAs. We have initiated four steps to seek the optimal combination of BAs that are (1) determining the anti-MRSA activity of single BA, (2) investigating the two-component combination to clarify the interactions among BAs by checkerboard assay, (3) investigating the multicomponent combination to determine the optimal ratio by quadratic rotation-orthogonal combination design, and (4) in vivo and in vitro validation of the optimal combination. The results showed that the interactions among BAs are related to their concentrations. The synergetic combinations included “berberine and epiberberine,” “jatrorrhizine and palmatine” and “jatrorrhizine and coptisine”; the antagonistic combinations included “coptisine and epiberberine”. The optimal combination was berberine : coptisine : jatrorrhizine : palmatine : epiberberine = 0.702 : 0.863 : 1 : 0.491 : 0.526, and the potency of the optimal combination on cyclophosphamide-immunocompromised mouse model was better than the natural combinations of herbs containing BAs. PMID:23634170

  9. Hydrocarbon and chlorinated hydrocarbon-soluble magnesium dialkoxides

    SciTech Connect

    Kamienski, C.W.

    1988-05-31

    This patent describes a process for the preparation of hydrocarbon or chlorinated hydrocarbon solvent solutions of magnesium dialkoxides, which comprises reacting a suspension of magnesium metal or magnesium amide, or a solution of a dialkyimagnesium compound, in a volatile hydrocarbon or chlorinated hydrocarbon solvent with an alcohol selected from the group of (a) aliphatic, cycloaliphatic and acyclic C/sub 5/-C/sub 18/ beta- and gamma-alkyl-substituted secondary and tertiary monohydric alcohols; or (b) mixtures of the (a) alcohols with C/sub 3/-C/sub 18/ aliphatic or cycloaliphatic beta- and gamma-alkyl-unsubstituted secondary or tertiary alcohols; or (c) mixtures of the (a) alcohols with C/sub 1/-C/sub 18/ aliphatic primary unsubstituted and 2-alkyl-substituted alcohols; the mole ratios of the (a) to the (b), and the (a) to the (c), alcohols being 1 of the (a) alcohols to 0.1 to 2 of the (b) and/or the (c) alcohols.

  10. Phase-Field Modeling of the Coarsening in Multi-component Systems

    NASA Astrophysics Data System (ADS)

    Kundin, Julia; Rezende, Joao Luiz Lopes; Emmerich, Heike

    2014-02-01

    A thermodynamically consistent method for the investigation of the coarsening behavior and in particular for the prediction of the secondary dendrite arm spacing (SDAS) in multi-component alloys is proposed which is based on the numerical simulation by means of a phase-field model. Existing variants of the phase-field model equations for multi-component systems were considered and their advantages and disadvantages were discussed. For the investigation of the coarsening behavior the variant described by the mixture composition and the entropy change was chosen. The method is applied to a high-alloy tool steel where it was found that elements such as C, Si, Mn decrease the SDAS whereas Cr increases. The resulting dependencies of the SDAS on alloy composition were compared to the analytical prediction of the coarsening model. For this aim the analytical model of the coarsening behavior in multi-component alloys [Rappaz and Boettinger, Acta Mater. 47 (1990)] was extended by taking into account the cross dependencies between the components in multi-component diffusion and the case of slow diffusion in the solid phase. The equilibrium parameters used in the phase-field model and in the analytical model were obtained from Thermo-Calc through global equilibrium calculations using the database TCFE7. The difference between both methods was found to be smaller than 2 pct in the investigated composition region.

  11. Dissolution, Cyclodextrin-Enhanced Solubilization, and Mass Removal of an Ideal Multicomponent Organic Liquid

    PubMed Central

    Carroll, Kenneth C.; Brusseau, Mark L.

    2010-01-01

    Laboratory experiments and mathematical modeling were conducted to examine the influence of a hydroxypropyl-beta-cyclodextrin (HPCD) solution on the dissolution of single- and three-component organic liquids. The results of batch experiments showed that HPCD-enhanced solubilization of the organic-liquid mixtures was ideal (describable using Raoult’s Law), and that solubilization-enhancement factors were independent of mixture composition. Addition of the HPCD solution to columns containing residual saturations of the organic liquid enhanced the dissolution and removal of all three compounds in the mixture. The results of the column experiments and multicomponent rate-limited dissolution modeling suggest that solubilization was ideal for both water and cyclodextrin flushing. Concomitantly, the mass-flux reduction versus mass removal behavior was ideal for all experiments. Mass transfer was increased for HPCD solubilization relative to the water flushing due to solubility and concentration-gradient enhancement. Organic-liquid composition did not significantly impact mass transfer coefficients, and fractional mass removal behavior during HPCD solubilization was nearly identical for each compound whether present as a single component or in a mixture. Additionally, mass transfer coefficients for aqueous and HPCD solubilization for single and multicomponent mixtures were not statistically different upon normalizing by the solubility enhancement factor. PMID:19233508

  12. A compatible Lagrangian hydrodynamic scheme for multicomponent flows with mixing

    SciTech Connect

    Chang, Chong; Stagg, Alan K

    2012-01-01

    We present a Lagrangian time integration scheme and compatible discretization for total energy conservation in multicomponent mixing simulations. Mixing behavior results from relative motion between species. Species velocities are determined by solving species momentum equations in a Lagrangian manner. Included in the species momentum equations are species artificial viscosity (since each species can undergo compression) and inter-species momentum exchange. Thermal energy for each species is also solved, including compression work and thermal dissipation caused by momentum exchange. The present procedure is applicable to mixing of an arbitrary number of species that may not be in pressure or temperature equilibrium. A traditional staggered stencil has been adopted to describe motion of each species. The computational mesh for the mixture is constructed in a Lagrangian manner using the mass-averaged mixture velocity. Species momentum equations are solved at the vertices of the mesh, and temporary species meshes are constructed and advanced in time using the resulting species velocities. Following the Lagrangian step, species quantities are advected (mapped) from the species meshes to the mixture mesh. Momentum exchange between species introduces work that must be included in an energy-conserving discretization scheme. This work has to be transformed to dissipation in order to effect a net change in species thermal energy. The dissipation between interacting species pairs is obtained by combining the momentum exchange work. The dissipation is then distributed to the species involved using a distribution factor based on species specific heats. The resulting compatible discretization scheme provides total energy conservation of the whole mixture. In addition, the numerical scheme includes conservative local energy exchange between species in mixture. Due to the relatively large species interaction coefficients, both the species momenta and energies are calculated

  13. Multicomponent liquid ion exchange with chabazite zeolites

    SciTech Connect

    Robinson, S.M.; Arnold, W.D. Jr.; Byers, C.W.

    1993-10-01

    In spite of the increasing commercial use of zeolites for binary and multicomponent sorption, the understanding of the basic mass-transfer processes associated with multicomponent zeolite ion-exchange systems is quite limited. This study was undertaken to evaluate Na-Ca-Mg-Cs-Sr ion exchange from an aqueous solution using a chabazite zeolite. Mass-transfer coefficients and equilibrium equations were determined from experimental batch-reactor data for single and multicomponent systems. The Langmuir isotherm was used to represent the equilibrium relationship for binary systems, and a modified Dubinin-Polyani model was used for the multicomponent systems. The experimental data indicate that diffusion through the microporous zeolite crystals is the primary diffusional resistance. Macropore diffusion also significantly contributes to the mass-transfer resistance. Various mass-transfer models were compared to the experimental data to determine mass-transfer coefficients. Effective diffusivities were obtained which accurately predicted experimental data using a variety of models. Only the model which accounts for micropore and macropore diffusion occurring in series accurately predicted multicomponent data using single-component diffusivities. Liquid and surface diffusion both contribute to macropore diffusion. Surface and micropore diffusivities were determined to be concentration dependent.

  14. Conscientiousness increases efficiency of multicomponent behavior

    PubMed Central

    Stock, Ann-Kathrin; Beste, Christian

    2015-01-01

    Many everyday situations require the flexible interruption and changing of different actions to achieve a goal. Several strategies can be applied to do so, but those requiring high levels of cognitive control seem to confer an efficiency (speed) advantage in situations requiring multi-component behavior. However, it is elusive in how far personality traits affect performance in such situations. Given that top-down control is an important aspect of personality and furthermore correlates with conscientiousness, N = 163 participants completed the NEO-FFI and performed an experimental (stop-change) paradigm assessing multicomponent behavior. Applying mathematical constraints to the behavioral data, we estimated the processing strategy of each individual. The results show that multicomponent behavior is selectively affected by conscientiousness which explained approximately 19% of the measured inter-individual behavioral variance. Conscientiousness should hence be seen as a major personality dimension modulating multicomponent behavior. Highly conscientious people showed a more effective, step-by-step processing strategy of different actions necessary to achieve a goal. In situations with simultaneous requirements, this strategy equipped them with an efficiency (speed) advantage towards individuals with lower conscientiousness. In sum, the results show that strategies and the efficiency with which people cope with situations requiring multicomponent behavior are strongly influenced by their personality. PMID:26503352

  15. Conscientiousness increases efficiency of multicomponent behavior.

    PubMed

    Stock, Ann-Kathrin; Beste, Christian

    2015-10-27

    Many everyday situations require the flexible interruption and changing of different actions to achieve a goal. Several strategies can be applied to do so, but those requiring high levels of cognitive control seem to confer an efficiency (speed) advantage in situations requiring multi-component behavior. However, it is elusive in how far personality traits affect performance in such situations. Given that top-down control is an important aspect of personality and furthermore correlates with conscientiousness, N = 163 participants completed the NEO-FFI and performed an experimental (stop-change) paradigm assessing multicomponent behavior. Applying mathematical constraints to the behavioral data, we estimated the processing strategy of each individual. The results show that multicomponent behavior is selectively affected by conscientiousness which explained approximately 19% of the measured inter-individual behavioral variance. Conscientiousness should hence be seen as a major personality dimension modulating multicomponent behavior. Highly conscientious people showed a more effective, step-by-step processing strategy of different actions necessary to achieve a goal. In situations with simultaneous requirements, this strategy equipped them with an efficiency (speed) advantage towards individuals with lower conscientiousness. In sum, the results show that strategies and the efficiency with which people cope with situations requiring multicomponent behavior are strongly influenced by their personality.

  16. Plasma Assisted Combustion Mechanism for Small Hydrocarbons

    DTIC Science & Technology

    2015-01-01

    Andrey Starikovskiy Nickolay Aleksandrov PRINCETON University Plasma Assisted Combustion  Mechanism for Small  Hydrocarbons Report Documentation Page...COVERED 00-00-2015 to 00-00-2015 4. TITLE AND SUBTITLE Plasma Assisted Combustion Mechanism for Small Hydrocarbons 5a. CONTRACT NUMBER 5b...Kinetics of ignition of saturated  hydrocarbons  by nonequilibrium plasma: C2H6‐ to C5H12‐containing mixtures. Combustion and Flame 156  (2009) 221–233

  17. Multi-Component Reactions in Heterocyclic Chemistry

    NASA Astrophysics Data System (ADS)

    Müller, Thomas J. J.; Orru, Romano V. A.; Chebanov, Valentin A.; Sakhno, Yana I.; Saraev, Vyacheslav E.; Muravyova, Elena A.; Andrushchenko, Anastasia Yu.; Desenko, Sergey M.; Akhmetova, V. R.; Khabibullina, G. R.; Rakhimova, E. B.; Vagapov, R. A.; Khairullina, R. R.; Niatshina, Z. T.; Murzakova, N. N.; Maslivets, Andrey N.; Voskressensky, Leonid G.; Danagulyan, Gevorg G.; Murtchyan, Armen D.; Tumanyan, Araksya K.; Banfi, Luca; Basso, Andrea; de Moliner, Fabio; Guanti, Giuseppe; Petricci, Elena; Riva, Renata; Taddei, Maurizio; Naimi-Jamal, M. Reza; Mashkouri, Sara; Sharifi, Ali; Przhevalski, Nikolai M.; Rozhkova, Elena N.; Tokmakov, Gennadii P.; Magedov, Igor V.; Armisheva, M. N.; Rassudihina, N. A.; Vahrin, M. I.; Gein, V. L.; Shaabani, Ahmad; Rezayan, Ali Hossein; Sarvary, Afshin; Heidary, Marjan; Ng, Seik Weng; Beliaev, Nikolai A.; Mokrushin, Vladimir S.; Paramonov, Igor V.; Ilyin, Alexey; Garkushenko, Anna K.; Dushek, Maria A.; Sagitullina, Galina P.; Sagitullin, Reva S.; Kysil, Volodymyr; Khvat, Alexander; Tsirulnikov, Sergey; Tkachenko, Sergey; Ivachtchenko, Alexandre; Gein, Vladimir L.; Panova, Olga S.; Ilyn, Alexey P.; Kravchenko, Dmitri V.; Potapov, Victor V.; Ivachtchenko, Alexandre V.; Vichegjanina, V. N.; Levandovskaya, E. B.; Gein, V. L.; Vahrin, M. I.; Vladimirov, I. N.; Zorina, A. A.; Nosova, N. V.; Gein, V. L.; Fedorova, O. V.; Vahrin, M. I.

    Multi-component and domino reactions are efficient and effective methods in the sustainable and diversity-oriented synthesis of heterocycles. In particular, transition metal-catalyzed multi-component sequences have recently gained considerable interest. Based upon the Sonogashira entry to alkynones, alkenones, and intermediate allenes, we have opened new avenues to the one-pot synthesis of numerous classes of heterocyclic frameworks in an MCR fashion. This methodological approach has now found various applications in one-pot syntheses of functional chromophores, pharmaceutically active compounds, and marine alkaloids and derivatives.

  18. Deposition of thin films of multicomponent materials

    NASA Technical Reports Server (NTRS)

    Thakoor, Sarita (Inventor)

    1993-01-01

    Composite films of multicomponent materials, such as oxides and nitrides, e.g., lead zirconate titanate, are deposited by dc magnetron sputtering, employing a rotating substrate holder, which rotates relative to a plurality of targets, one target for each metal element of the multicomponent material. The sputtering is carried out in a reactive atmosphere. The substrates on which the layers are deposited are at ambient temperature. Following deposition of the composite film, the film is heated to a temperature sufficient to initiate a solid state reaction and form the final product, which is substantially single phase and substantially homogeneous.

  19. A modified microbial adhesion to hydrocarbons assay to account for the presence of hydrocarbon droplets.

    PubMed

    Zoueki, Caroline Warne; Tufenkji, Nathalie; Ghoshal, Subhasis

    2010-04-15

    The microbial adhesion to hydrocarbons (MATH) assay has been used widely to characterize microbial cell hydrophobicity and/or the extent of cell adhesion to hydrophobic liquids. The classical MATH assay involves spectrophotometric absorbance measurements of the initial and final cell concentrations in an aqueous cell suspension that has been contacted with a hydrocarbon liquid. In this study, microscopic examination of the aqueous cell suspension after contact with hexadecane or a hexadecane/toluene mixture revealed the presence of hydrocarbon droplets. The hydrocarbon droplets contributed to the absorbance values during spectrophotometric measurements and caused erroneous estimates of cell concentrations and extents of microbial adhesion. A modified MATH assay that avoids such artefacts is proposed here. In this modified assay, microscopic examination of the aqueous suspension and direct cell counts provides cell concentrations that are free of interference from hydrocarbon droplets. The presence of hydrocarbon droplets was noted in MATH assays performed with three bacterial strains, and two different hydrocarbons, at ionic strengths of 0.2 mM and 20 mM and pH 6. In these experiments, the formation of quasi-stable hydrocarbon droplets cannot be attributed to the presence of biosurfactants, or stabilization by biocolloids. The presence of surface potential at the hydrocarbon-water interface that was characterized by electrophoretic mobility of up to -1 and -2 microm cm/Vs, likely caused the formation of the quasi-stable hydrocarbon droplets that provided erroneous results using the classical MATH assay.

  20. Detailed Investigation of Separation Performance of a MMM for Removal of Higher Hydrocarbons under Varying Operating Conditions

    PubMed Central

    Mushardt, Heike; Müller, Marcus; Shishatskiy, Sergey; Wind, Jan; Brinkmann, Torsten

    2016-01-01

    Mixed-matrix membranes (MMMs) are promising candidates to improve the competitiveness of membrane technology against energy-intensive conventional technologies. In this work, MMM composed of poly(octylmethylsiloxane) (POMS) and activated carbon (AC) were investigated with respect to separation of higher hydrocarbons (C3+) from permanent gas streams. Membranes were prepared as thin film composite membranes on a technical scale and characterized via scanning electron microscopy (SEM) and permeation measurements with binary mixtures of n-C4H10/CH4 under varying operating conditions (feed and permeate pressure, temperature, feed gas composition) to study the influence on separation performance. SEM showed good contact and absence of defects. Lower permeances but higher selectivities were found for MMM compared to pure POMS membrane. Best results were obtained at high average fugacity and activity of n-C4H10 with the highest selectivity estimated to be 36.4 at n-C4H10 permeance of 12 mN3/(m2·h·bar). Results were complemented by permeation of a multi-component mixture resembling a natural gas application, demonstrating the superior performance of MMM. PMID:26927194

  1. New selective solvents of aromatic hydrocarbons based on petroleum sulfides

    SciTech Connect

    Nikitin, Yu.E.; Baikova, A.Ya.; Vakhitova, N.G.; Khorosheva, S.I.; Murinov, Yu.I.

    1985-01-01

    The present work examines the extractive properties of petroleum sulfoxides (PSO) and their mixtures with other industrial extraction agents. Substitutes are tested to find inexpensive, high-boiling selective solvents and as extractive rectification agents for aromatic hydrocarbons. Effective extraction agents were proposed for the recovery of benzene and toluene from hydrocarbon mixtures during extractive rectification. Petroleum sulfoxides and their synergistic mixtures with diethylene glycol and dimethylformamide, enabled benzene and toluene to be recovered to the extent of 91-99% with a purity of 92-98%; when recovery is from a mixture enriched with benzene, purity increases to 99.5%.

  2. Phase-field theory of multicomponent incompressible Cahn-Hilliard liquids

    NASA Astrophysics Data System (ADS)

    Tóth, Gyula I.; Zarifi, Mojdeh; Kvamme, Bjørn

    2016-01-01

    In this paper, a generalization of the Cahn-Hilliard theory of binary liquids is presented for multicomponent incompressible liquid mixtures. First, a thermodynamically consistent convection-diffusion-type dynamics is derived on the basis of the Lagrange multiplier formalism. Next, a generalization of the binary Cahn-Hilliard free-energy functional is presented for an arbitrary number of components, offering the utilization of independent pairwise equilibrium interfacial properties. We show that the equilibrium two-component interfaces minimize the functional, and we demonstrate that the energy penalization for multicomponent states increases strictly monotonously as a function of the number of components being present. We validate the model via equilibrium contact angle calculations in ternary and quaternary (four-component) systems. Simulations addressing liquid-flow-assisted spinodal decomposition in these systems are also presented.

  3. Wall boundary equations with slip and catalysis for multicomponent, nonequilibrium gas flows

    NASA Technical Reports Server (NTRS)

    Scott, C. D.

    1973-01-01

    Boundary equations obtained for a low Reynolds number, high enthalpy gas flow in regions of velocity slip and temperature jump are presented. The formulation treats, through a first-order distribution function used to include multicomponent diffusion, a multicomponent gas mixture that may be in nonequilibrium with finite-rate catalytic recombination occurring on the wall. In the boundary equations, which are obtained for use in flow-field calculations applicable to low-density flow regimes, a simplified gas/wall interaction is assumed wherein individual atoms or molecules either reflect specularly off the wall or stick and are fully accommodated. Fluxes in terms of evaluated integrals over the distribution function and integrals necessary for determining fluxes are given.

  4. Numerical Analysis of Multicomponent Suspension Droplets in High-Velocity Flame Spray Process

    NASA Astrophysics Data System (ADS)

    Gozali, Ebrahim; Mahrukh, Mahrukh; Gu, Sai; Kamnis, Spyros

    2014-08-01

    The liquid feedstock or suspension as a different mixture of liquid fuel ethanol and water is numerically studied in high-velocity suspension flame spray (HVSFS) process, and the results are compared for homogenous liquid feedstock of ethanol and water. The effects of mixture on droplet aerodynamic breakup, evaporation, combustion, and gas dynamics of HVSFS process are thoroughly investigated. The exact location where the particle heating is initiated (above the carrier liquid boiling point) can be controlled by increasing the water content in the mixture. In this way, the particle inflight time in the high-temperature gas regions can be adjusted avoiding adverse effects from surface chemical transformations. The mixture is modeled as a multicomponent droplet, and a convection/diffusion model, which takes into account the convective flow of evaporating material from droplet surface, is used to simulate the suspension evaporation. The model consists of several sub-models that include premixed combustion of propane-oxygen, non-premixed ethanol-oxygen combustion, modeling of multicomponent droplet breakup and evaporation, as well as heat and mass transfer between liquid droplets and gas phase.

  5. Multicomponent Synthesis of α-Branched Amides

    PubMed Central

    DeBenedetto, Mikkel V.; Green, Michael E.; Wan, Shuangyi; Park, Jung-Hyun; Floreancig, Paul E.

    2009-01-01

    α-Branched amides are prepared by multicomponent reactions in which nitriles undergo hydrozirconation to form metalloimines that react with acyl chlorides. The resulting acylimines react with a variety of π-nucleophiles in the presence of Lewis acids to form the desired amides. PMID:19152262

  6. Modeling the evaporation of sessile multi-component droplets.

    PubMed

    Diddens, C; Kuerten, J G M; van der Geld, C W M; Wijshoff, H M A

    2017-02-01

    We extended a mathematical model for the drying of sessile droplets, based on the lubrication approximation, to binary mixture droplets. This extension is relevant for e.g. inkjet printing applications, where ink consisting of several components are used. The extension involves the generalization of an established vapor diffusion-limited evaporation model to multi-component mixtures. The different volatilities of the liquid components generate a composition gradient at the liquid-air interface. The model takes the composition-dependence of the mass density, viscosity, surface tension, mutual diffusion coefficient and thermodynamic activities into account. This leads to a variety of effects ranging from solutal Marangoni flow over deviations from the typical spherical cap shape to an entrapped residual amount of the more volatile component at later stages of the drying. These aspects are discussed in detail on the basis of the numerical results for water-glycerol and water-ethanol droplets. The results show good agreement with experimental findings. Finally, the accuracy of the lubrication approximation is assessed by comparison with a finite element method.

  7. A novel multicomponent stimulus device for use in olfactory experiments.

    PubMed

    Olsson, Shannon B; Kuebler, Linda S; Veit, Daniel; Steck, Kathrin; Schmidt, Alexandra; Knaden, Markus; Hansson, Bill S

    2011-01-30

    Olfactory studies have expanded beyond the study of single compound odor perception to explore the processing of complex mixtures and blends. The spatiotemporal presentation of blend stimuli is a challenging task requiring volatiles with diverse chemical and physical properties to be presented as a unified stimulus. This not only necessitates accurate control of the timing and homogeneity of the odor stream, but requires attention to the concentration of each blend component presented. We have developed a novel, multicomponent stimulus system for use in olfactory experiments that is capable of presenting up to 8 different odors simultaneously or in sequence at defined concentrations and time scales. Each odor is separated to minimize physical or chemical interactions, and stimulations are performed from a saturated headspace of the odor solution. Stimulus concentrations can be measured empirically or estimated using common gas laws. Photoionization detector measurements show that stimuli could be presented as cohesive blends or single components at frequencies of at least 10Hz without leakage or contamination. Solid phase microextraction measurements also show that the concentration of each component could be equilibrated through regulation of each component line's flow rate based on the different partial vapor pressures of the odorants. This device provides a unique method for introducing complex volatile mixtures for olfactory studies in a variety of animal taxa and allows for accurate control of odor intensities in both time and space.

  8. Margination and demargination in confined multicomponent suspensions: a parametric study

    NASA Astrophysics Data System (ADS)

    Graham, Michael; Sinha, Kushal; Henriquez Rivera, Rafael

    2014-11-01

    Blood and other multicomponent suspensions display a segregation behavior in which different components are differentially distributed in the cross-stream direction during flow in a confined geometry such as an arteriole or a microfluidic device. In blood the platelets and leukocytes are strongly segregated to the near wall region and are said to be ``marginated.'' The effects of particle size, shape and rigidity on segregation behavior in confined simple shear flow of binary suspensions are computationally investigated here. The results show that in a mixture of particles with same shape and different membrane rigidity, the stiffer particles marginate while the flexible particles demarginate, moving toward the center of the channel. In a mixture of particle with same membrane rigidity and different shape, particles with smaller aspect ratio marginate while those with higher aspect ratio demarginate. These results are consistent with theoretical arguments based on wall-induced migration and pair collision dynamics. An analytical solution is presented for a model problem that reveals qualitatively different behavior in various parameter regimes. Finally, effects of viscoelasticity of the suspending phase on margination are examined. This work was supported by the NSF under Grants CBET-1132579 and CBET-1436082.

  9. Going Beyond, Going Further: Chemical Properties of Commonly Available Hydrocarbons.

    ERIC Educational Resources Information Center

    Perina, Ivo

    1985-01-01

    Background information, procedures used, and safety considerations are provided for experiments using natural gas. They include: (1) exploding a mixture of natural gas and oxygen; (2) testing for unsaturated hydrocarbons in natural gas; (3) substituting higher saturated hydrocarbons contained in kerosene with bromine; and (4) the pyrolysis of…

  10. Mercury-free PVT apparatus for thermophysical property analyses of hydrocarbon reservoir fluids. Final report, August 16, 1990--July 31, 1992

    SciTech Connect

    Lansangan, R.M.; Lievois, J.S.

    1992-08-31

    Typical reservoir fluid analyses of complex, multicomponent hydrocarbon mixtures include the volumetric properties, isothermal compressibility, thermal expansivity, equilibrium ratios, saturation pressure, viscosities, etc. These parameters are collectively referred to as PVT properties, an acronym for the primary state variables; pressure, volume, and temperature. The reservoir engineer incorporates this information together with the porous media description in performing material balance calculations. These calculations lead to the determination (estimation) of the initial hydrocarbon in-place, the future reservoir performance, the optimal production scheme, and the ultimate hydrocarbon recovery. About four years ago, Ruska Instrument Corporation embarked on a project to develop an apparatus designed to measure PVT properties that operates free of mercury. The result of this endeavor is the 2370 Hg-Free PVT system which has been in the market for the last three years. The 2370 has evolved from the prototype unit to its present configuration which is described briefly in this report. The 2370 system, although developed as a system-engineered apparatus based on existing technology, has not been exempt from this burden-of-proof Namely, the performance of the apparatus under routine test conditions with real reservoir fluids. This report summarizes the results of the performance and applications testing of the 2370 Hg-Free PVT system. Density measurements were conducted on a pure fluid. The results were compared against literature values and the prediction of an equation of state. Routine reservoir fluid analyses were conducted with a black oil and a retrograde condensate gas mixtures. Limited comparison of the results were performed based on the same tests performed on a conventional mercury-based PVT apparatus. The results of these tests are included in this report.

  11. Improved AIOMFAC model parameterisation of the temperature dependence of activity coefficients for aqueous organic mixtures

    NASA Astrophysics Data System (ADS)

    Ganbavale, G.; Zuend, A.; Marcolli, C.; Peter, T.

    2014-06-01

    This study presents a new, improved parameterisation of the temperature dependence of activity coefficients in the AIOMFAC (Aerosol Inorganic-Organic Mixtures Functional groups Activity Coefficients) model applicable for aqueous as well as water-free organic solutions. For electrolyte-free organic and organic-water mixtures the AIOMFAC model uses a group-contribution approach based on UNIFAC (UNIversal quasi-chemical Functional-group Activity Coefficients). This group-contribution approach explicitly accounts for interactions among organic functional groups and between organic functional groups and water. The previous AIOMFAC version uses a simple parameterisation of the temperature dependence of activity coefficients, aimed to be applicable in the temperature range from ~275 to ~400 K. With the goal to improve the description of a wide variety of organic compounds found in atmospheric aerosols, we extend the AIOMFAC parameterisation for the functional groups carboxyl, hydroxyl, ketone, aldehyde, ether, ester, alkyl, aromatic carbon-alcohol, and aromatic hydrocarbon to atmospherically relevant low temperatures with the introduction of a new temperature dependence parameterisation. The improved temperature dependence parameterisation is derived from classical thermodynamic theory by describing effects from changes in molar enthalpy and heat capacity of a multicomponent system. Thermodynamic equilibrium data of aqueous organic and water-free organic mixtures from the literature are carefully assessed and complemented with new measurements to establish a comprehensive database, covering a wide temperature range (~190 to ~440 K) for many of the functional group combinations considered. Different experimental data types and their processing for the estimation of AIOMFAC model parameters are discussed. The new AIOMFAC parameterisation for the temperature dependence of activity coefficients from low to high temperatures shows an overall improvement of 25% in comparison to

  12. Recovery of nitrogen and light hydrocarbons from polyalkene purge gas

    DOEpatents

    Zwilling, Daniel Patrick; Golden, Timothy Christoph; Weist, Jr., Edward Landis; Ludwig, Keith Alan

    2003-06-10

    A method for the separation of a gas mixture comprises (a) obtaining a feed gas mixture comprising nitrogen and at least one hydrocarbon having two to six carbon atoms; (b) introducing the feed gas mixture at a temperature of about 60.degree. F. to about 105.degree. F. into an adsorbent bed containing adsorbent material which selectively adsorbs the hydrocarbon, and withdrawing from the adsorbent bed an effluent gas enriched in nitrogen; (c) discontinuing the flow of the feed gas mixture into the adsorbent bed and depressurizing the adsorbent bed by withdrawing depressurization gas therefrom; (d) purging the adsorbent bed by introducing a purge gas into the bed and withdrawing therefrom an effluent gas comprising the hydrocarbon, wherein the purge gas contains nitrogen at a concentration higher than that of the nitrogen in the feed gas mixture; (e) pressurizing the adsorbent bed by introducing pressurization gas into the bed; and (f) repeating (b) through (e) in a cyclic manner.

  13. Determining Oxidation Rates in Multi-component Organic Aerosols

    NASA Astrophysics Data System (ADS)

    Sage, A. M.; Weitkamp, E. A.; Huff Hartz, K. E.; Robinson, A. L.; Donahue, N. M.

    2006-12-01

    Aerosol composition influences the kinetics of condensed-phase organic species, making extrapolation of rate constants from single-component systems to atmospherically-relevant mixtures difficult. Using a mixed-phase relative rate constants approach, we have overcome this difficulty, obtaining heterogeneous oxidation rate constants for each species in several multi-component organic mixtures. We have also derived a compound- specific uptake coefficient that relates these rate constants to previous uptake measurements. In the ozonolysis of model meat-cooking mixtures, we observe significant decay of saturated and unsaturated acids and sterols. By relating the observed decomposition of condensed-phase species to that of gas-phase standards, we track the evolution of effective rate constants for oleic acid and palmitoleic acid oxidation as the aerosol is chemically processed. Each decreases by nearly a factor of ten over the course of an experiment. Rate constants also depend strongly on aerosol composition, changing by more than an order of magnitude with increasing mixture complexity. To compare these results with previous results, we have derived a compound-specific uptake coefficient (γi' for condensed-phase species i), which describes the kinetics of reactive uptake in mixtures and can be meaningfully related to the traditional uptake coefficient. We express uptake in terms of the concentrations of condensed-phase species, and to do so accurately, we use alkanoic acids to correct the decay of reactive alkenoic acids for secondary chemistry. This correction is incorporated into the definition of γi', and in terms of γi', the standard uptake coefficient can be written as: γ=∑χiγi', where χi is the mass fraction of species i and the summation is over all oxidized species. By using condensed-phase decay to calculate the uptake, we have apportioned reactive uptake among responsible species. This provides information not only about the potential of a particle

  14. Mathematical model of the component mixture distribution in the molten cast iron during centrifugation (sedimentation)

    NASA Astrophysics Data System (ADS)

    Bikulov, R. A.; Kotlyar, L. M.

    2014-12-01

    For the development and management of the manufacturing processes of axisymmetric articles with compositional structure by centrifugal casting method [1,2,3,4] is necessary to create a generalized mathematical model of the dynamics of component mixture in the molten cast iron during centrifugation. In article. based on the analysis of the dynamics of two-component mixture at sedimentation, a method of successive approximations to determine the distribution of a multicomponent mixture by centrifugation in a parabolic crucible is developed.

  15. Catalytic conversion of alcohols to hydrocarbons with low benzene content

    DOEpatents

    Narula, Chaitanya K.; Davison, Brian H.; Keller, Martin

    2016-03-08

    A method for converting an alcohol to a hydrocarbon fraction having a lowered benzene content, the method comprising: converting said alcohol to a hydrocarbon fraction by contacting said alcohol, under conditions suitable for converting said alcohol to said hydrocarbon fraction, with a metal-loaded zeolite catalyst catalytically active for converting said alcohol to said hydrocarbon fraction, and contacting said hydrocarbon fraction with a benzene alkylation catalyst, under conditions suitable for alkylating benzene, to form alkylated benzene product in said hydrocarbon fraction. Also described is a catalyst composition useful in the method, comprising a mixture of (i) a metal-loaded zeolite catalyst catalytically active for converting said alcohol to said hydrocarbon, and (ii) a benzene alkylation catalyst, in which (i) and (ii) may be in a mixed or separated state. A reactor for housing the catalyst and conducting the reaction is also described.

  16. Catalytic conversion of alcohols to hydrocarbons with low benzene content

    SciTech Connect

    Narula, Chaitanya K.; Davison, Brian H.; Keller, Martin

    2016-09-06

    A method for converting an alcohol to a hydrocarbon fraction having a lowered benzene content, the method comprising: converting said alcohol to a hydrocarbon fraction by contacting said alcohol, under conditions suitable for converting said alcohol to said hydrocarbon fraction, with a metal-loaded zeolite catalyst catalytically active for converting said alcohol to said hydrocarbon fraction, and contacting said hydrocarbon fraction with a benzene alkylation catalyst, under conditions suitable for alkylating benzene, to form alkylated benzene product in said hydrocarbon fraction. Also described is a catalyst composition useful in the method, comprising a mixture of (i) a metal-loaded zeolite catalyst catalytically active for converting said alcohol to said hydrocarbon, and (ii) a benzene alkylation catalyst, in which (i) and (ii) may be in a mixed or separated state. A reactor for housing the catalyst and conducting the reaction is also described.

  17. Illite and hydrocarbon exploration

    PubMed Central

    Pevear, David R.

    1999-01-01

    Illite is a general term for the dioctahedral mica-like clay mineral common in sedimentary rocks, especially shales. Illite is of interest to the petroleum industry because it can provide a K-Ar isotope date that constrains the timing of basin heating events. It is critical to establish that hydrocarbon formation and migration occurred after the formation of the trap (anticline, etc.) that is to hold the oil. Illite also may precipitate in the pores of sandstone reservoirs, impeding fluid flow. Illite in shales is a mixture of detrital mica and its weathering products with diagenetic illite formed by reaction with pore fluids during burial. K-Ar ages are apparent ages of mixtures of detrital and diagenetic end members, and what we need are the ages of the end members themselves. This paper describes a methodology, based on mineralogy and crystallography, for interpreting the K-Ar ages from illites in sedimentary rocks and for estimating the ages of the end members. PMID:10097055

  18. Methods for dispersing hydrocarbons using autoclaved bacteria

    DOEpatents

    Tyndall, R.L.

    1996-11-26

    A method of dispersing a hydrocarbon includes the following steps: providing a bacterium selected from the following group: ATCC 85527, ATCC 75529, and ATCC 55638, a mutant of any one of these bacteria possessing all the identifying characteristics of any one of these bacteria, and mixtures; autoclaving the bacterium to derive a dispersant solution; and contacting the dispersant solution with a hydrocarbon to disperse the hydrocarbon. Moreover, a method for preparing a dispersant solution includes the following steps: providing a bacterium selected from the following group: ATCC 75527, ATCC 75529, and ATCC 55638, a mutant of any one of these bacteria possessing all the identifying characteristics of any one of these bacteria, and mixtures; and autoclaving the bacterium to derive a dispersant solution.

  19. Methods for dispersing hydrocarbons using autoclaved bacteria

    DOEpatents

    Tyndall, Richard L.

    1996-01-01

    A method of dispersing a hydrocarbon includes the steps: providing a bacterium selected from the following group: ATCC 85527, ATCC 75529, and ATCC 55638, a mutant of any one of these bacteria possessing all the identifying characteristics of any one of these bacteria, and mixtures thereof; autoclaving the bacterium to derive a dispersant solution therefrom; and contacting the dispersant solution with a hydrocarbon to disperse the hydrocarbon. Moreover, a method for preparing a dispersant solution includes the following steps: providing a bacterium selected from the following group: ATCC 75527, ATCC 75529, and ATCC 55638, a mutant of any one of these bacteria possessing all the identifying characteristics of any one of these bacteria, and mixtures thereof; and autoclaving the bacterium to derive a dispersant solution therefrom.

  20. Method and apparatus for detecting gem-polyhalogenated hydrocarbons

    DOEpatents

    Anderson, deceased, William G.; Anderson, legal representative, Johanna S.

    1990-01-01

    A method and optrode for detecting gem polyhalogenated hydrocarbons in a sample fluid based on a single phase Fujiwara reaction as provided. The method comprises contacting a reaction mixture with a sample fluid which contains the gem-polyhalogenated hydrocarbons. The reaction mixture comprises an aqueous solution of pyridine or derivative thereof and a hindered nitrogen base. Upon contact a fluorescent and/or chromgenic reaction product forms whose fluorescence and/or absorbance is related to the concentration of gem-polyhalogenated hydrocarbons in the sample fluid.

  1. Noble gas and hydrocarbon tracers in multiphase unconventional hydrocarbon systems: Toward integrated advanced reservoir simulators

    NASA Astrophysics Data System (ADS)

    Darrah, T.; Moortgat, J.; Poreda, R. J.; Muehlenbachs, K.; Whyte, C. J.

    2015-12-01

    Although hydrocarbon production from unconventional energy resources has increased dramatically in the last decade, total unconventional oil and gas recovery from black shales is still less than 25% and 9% of the totals in place, respectively. Further, the majority of increased hydrocarbon production results from increasing the lengths of laterals, the number of hydraulic fracturing stages, and the volume of consumptive water usage. These strategies all reduce the economic efficiency of hydrocarbon extraction. The poor recovery statistics result from an insufficient understanding of some of the key physical processes in complex, organic-rich, low porosity formations (e.g., phase behavior, fluid-rock interactions, and flow mechanisms at nano-scale confinement and the role of natural fractures and faults as conduits for flow). Noble gases and other hydrocarbon tracers are capably of recording subsurface fluid-rock interactions on a variety of geological scales (micro-, meso-, to macro-scale) and provide analogs for the movement of hydrocarbons in the subsurface. As such geochemical data enrich the input for the numerical modeling of multi-phase (e.g., oil, gas, and brine) fluid flow in highly heterogeneous, low permeability formations Herein we will present a combination of noble gas (He, Ne, Ar, Kr, and Xe abundances and isotope ratios) and molecular and isotopic hydrocarbon data from a geographically and geologically diverse set of unconventional hydrocarbon reservoirs in North America. Specifically, we will include data from the Marcellus, Utica, Barnett, Eagle Ford, formations and the Illinois basin. Our presentation will include geochemical and geological interpretation and our perspective on the first steps toward building an advanced reservoir simulator for tracer transport in multicomponent multiphase compositional flow (presented separately, in Moortgat et al., 2015).

  2. Approximate equations of state in two-temperature plasma mixtures

    SciTech Connect

    Ramshaw, John D.; Cook, Andrew W.

    2014-02-15

    Approximate thermodynamic state relations for multicomponent atomic and molecular gas mixtures are often constructed by artificially partitioning the mixture into its constituent materials and requiring the separated materials to be in temperature and pressure equilibrium. Iterative numerical algorithms have been employed to enforce this equilibration and compute the resulting approximate state relations in single-temperature mixtures. In partially ionized gas mixtures, there is both theoretical and empirical evidence that equilibrating the chemical potentials, number densities, or partial pressures of the free electrons is likely to produce more accurate results than equilibrating the total pressures. Moreover, in many situations of practical interest the free electrons and heavy particles have different temperatures. In this paper, we present a generalized algorithm for equilibrating the heavy-particle and electron temperatures and a third user-specified independent thermodynamic variable in a two-temperature plasma mixture. Test calculations based on the equilibration of total pressure vs. electron pressure are presented for three different mixtures.

  3. Numerical modeling of temperature and species distributions in hydrocarbon reservoirs

    NASA Astrophysics Data System (ADS)

    Bolton, Edward W.; Firoozabadi, Abbas

    2014-01-01

    We examine bulk fluid motion and diffusion of multicomponent hydrocarbon species in porous media in the context of nonequilibrium thermodynamics, with particular focus on the phenomenology induced by horizontal thermal gradients at the upper and lower horizontal boundaries. The problem is formulated with respect to the barycentric (mass-averaged) frame of reference. Thermally induced convection, with fully time-dependent temperature distributions, can lead to nearly constant hydrocarbon composition, with minor unmixing due to thermal gradients near the horizontal boundaries. Alternately, the composition can be vertically segregated due to gravitational effects. Independent and essentially steady solutions have been found to depend on how the compositions are initialized in space and may have implications for reservoir history. We also examine injection (to represent filling) and extraction (to represent leakage) of hydrocarbons at independent points and find a large distortion of the gas-oil contact for low permeability.

  4. Silver and gold-catalyzed multicomponent reactions

    PubMed Central

    Abbiati, Giorgio

    2014-01-01

    Summary Silver and gold salts and complexes mainly act as soft and carbophilic Lewis acids even if their use as σ-activators has been rarely reported. Recently, transformations involving Au(I)/Au(III)-redox catalytic systems have been reported in the literature. In this review we highlight all these aspects of silver and gold-mediated processes and their application in multicomponent reactions. PMID:24605168

  5. Diffusion Of Mass In Evaporating Multicomponent Drops

    NASA Technical Reports Server (NTRS)

    Bellan, Josette; Harstad, Kenneth G.

    1992-01-01

    Report summarizes study of diffusion of mass and related phenomena occurring in evaporation of dense and dilute clusters of drops of multicomponent liquids intended to represent fuels as oil, kerosene, and gasoline. Cluster represented by simplified mathematical model, including global conservation equations for entire cluster and conditions on boundary between cluster and ambient gas. Differential equations of model integrated numerically. One of series of reports by same authors discussing evaporation and combustion of sprayed liquid fuels.

  6. Principal conversions of hydrocarbons in hydrotreating distillate lube raffinate

    SciTech Connect

    Chesnokov, A.A.; Kogan, L.O.; Kozlova, N.M.; Muchinskii, Ya.D.

    1983-01-01

    This article reports on a study of the principal conversions of hydrocarbons in hydrotreating a raffinate from phenol treating, obtained from a mixture of Volga-Ural and West Siberian crudes. It examines naphthenic hydrocarbons, alkylbenzenes, naphthalene hydrocarbons, and phenanthrenes. The degree of conversion of all groups of the aromatic hydrocarbons is considerably greater than the degree of conversion of the naphthenes. The greater the conversion of aromatics, the more significant are the changes in their physicochemical properties. Substantial decreases in the viscosity, density, and refractive index, and increases in the viscosity index are observed.

  7. Mechanism reduction for multicomponent surrogates: A case study using toluene reference fuels

    DOE PAGES

    Niemeyer, Kyle E.; Sung, Chih-Jen

    2014-11-01

    Strategies and recommendations for performing skeletal reductions of multicomponent surrogate fuels are presented, through the generation and validation of skeletal mechanisms for a three-component toluene reference fuel. Using the directed relation graph with error propagation and sensitivity analysis method followed by a further unimportant reaction elimination stage, skeletal mechanisms valid over comprehensive and high-temperature ranges of conditions were developed at varying levels of detail. These skeletal mechanisms were generated based on autoignition simulations, and validation using ignition delay predictions showed good agreement with the detailed mechanism in the target range of conditions. When validated using phenomena other than autoignition, suchmore » as perfectly stirred reactor and laminar flame propagation, tight error control or more restrictions on the reduction during the sensitivity analysis stage were needed to ensure good agreement. In addition, tight error limits were needed for close prediction of ignition delay when varying the mixture composition away from that used for the reduction. In homogeneous compression-ignition engine simulations, the skeletal mechanisms closely matched the point of ignition and accurately predicted species profiles for lean to stoichiometric conditions. Furthermore, the efficacy of generating a multicomponent skeletal mechanism was compared to combining skeletal mechanisms produced separately for neat fuel components; using the same error limits, the latter resulted in a larger skeletal mechanism size that also lacked important cross reactions between fuel components. Based on the present results, general guidelines for reducing detailed mechanisms for multicomponent fuels are discussed.« less

  8. Mechanism reduction for multicomponent surrogates: A case study using toluene reference fuels

    SciTech Connect

    Niemeyer, Kyle E.; Sung, Chih-Jen

    2014-11-01

    Strategies and recommendations for performing skeletal reductions of multicomponent surrogate fuels are presented, through the generation and validation of skeletal mechanisms for a three-component toluene reference fuel. Using the directed relation graph with error propagation and sensitivity analysis method followed by a further unimportant reaction elimination stage, skeletal mechanisms valid over comprehensive and high-temperature ranges of conditions were developed at varying levels of detail. These skeletal mechanisms were generated based on autoignition simulations, and validation using ignition delay predictions showed good agreement with the detailed mechanism in the target range of conditions. When validated using phenomena other than autoignition, such as perfectly stirred reactor and laminar flame propagation, tight error control or more restrictions on the reduction during the sensitivity analysis stage were needed to ensure good agreement. In addition, tight error limits were needed for close prediction of ignition delay when varying the mixture composition away from that used for the reduction. In homogeneous compression-ignition engine simulations, the skeletal mechanisms closely matched the point of ignition and accurately predicted species profiles for lean to stoichiometric conditions. Furthermore, the efficacy of generating a multicomponent skeletal mechanism was compared to combining skeletal mechanisms produced separately for neat fuel components; using the same error limits, the latter resulted in a larger skeletal mechanism size that also lacked important cross reactions between fuel components. Based on the present results, general guidelines for reducing detailed mechanisms for multicomponent fuels are discussed.

  9. Multicomponent gas sorption Joule-Thomson refrigeration

    NASA Technical Reports Server (NTRS)

    Jones, Jack A. (Inventor); Petrick, S. Walter (Inventor); Bard, Steven (Inventor)

    1991-01-01

    The present invention relates to a cryogenic Joule-Thomson refrigeration capable of pumping multicomponent gases with a single stage sorption compressor system. Alternative methods of pumping a multicomponent gas with a single stage compressor are disclosed. In a first embodiment, the sorbent geometry is such that a void is defined near the output of the sorption compressor. When the sorbent is cooled, the sorbent primarily adsorbs the higher boiling point gas such that the lower boiling point gas passes through the sorbent to occupy the void. When the sorbent is heated, the higher boiling point gas is desorbed at high temperature and pressure and thereafter propels the lower boiling point gas out of the sorption compressor. A mixing chamber is provided to remix the constituent gases prior to expansion of the gas through a Joule-Thomson valve. Other methods of pumping a multicomponent gas are disclosed. For example, where the sorbent is porous and the low boiling point gas does not adsorb very well, the pores of the sorbent will act as a void space for the lower boiling point gas. Alternatively, a mixed sorbent may be used where a first sorbent component physically adsorbs the high boiling point gas and where the second sorbent component chemically absorbs the low boiling point gas.

  10. A Course in Transport Phenomena in Multicomponent, Multiphase, Reacting Systems.

    ERIC Educational Resources Information Center

    Carbonell, R. G.; Whitaker, S.

    1978-01-01

    This course concentrates on a rigorous development of the multicomponent transport equations, boundary conditions at phase interfaces, and volume-averaged transport equations for multiphase reacting systems. (BB)

  11. Low velocity ion stopping in binary ionic mixtures

    SciTech Connect

    Tashev, Bekbolat; Baimbetov, Fazylkhan; Deutsch, Claude; Fromy, Patrice

    2008-10-15

    Attention is focused on the low ion velocity stopping mechanisms in multicomponent and dense target plasmas built of quasiclassical electron fluids neutralizing binary ionic mixtures, such as, deuterium-tritium of current fusion interest, proton-heliumlike iron in the solar interior or proton-helium ions considered in planetology, as well as other mixtures of fiducial concern in the heavy ion beam production of warm dense matter at Bragg peak conditions. The target plasma is taken in a multicomponent dielectric formulation a la Fried-Conte. The occurrence of projectile ion velocities (so-called critical) for which target electron slowing down equals that of given target ion components is also considered. The corresponding multiquadrature computations, albeit rather heavy, can be monitored analytical through a very compact code operating a PC cluster. Slowing down results are systematically scanned with respect to target temperature and electron density, as well as ion composition.

  12. Digital holographic microscopy of phase separation in multicomponent lipid membranes

    NASA Astrophysics Data System (ADS)

    Farzam Rad, Vahideh; Moradi, Ali-Reza; Darudi, Ahmad; Tayebi, Lobat

    2016-12-01

    Lateral in-homogeneities in lipid compositions cause microdomains formation and change in the physical properties of biological membranes. With the presence of cholesterol and mixed species of lipids, phospholipid membranes segregate into lateral domains of liquid-ordered and liquid-disordered phases. Coupling of two-dimensional intralayer phase separations and interlayer liquid-crystalline ordering in multicomponent membranes has been previously demonstrated. By the use of digital holographic microscopy (DHMicroscopy), we quantitatively analyzed the volumetric dynamical behavior of such membranes. The specimens are lipid mixtures composed of sphingomyelin, cholesterol, and unsaturated phospholipid, 1,2-dioleoyl-sn-glycero-3-phosphocholine. DHMicroscopy in a transmission mode is an effective tool for quantitative visualization of phase objects. By deriving the associated phase changes, three-dimensional information on the morphology variation of lipid stacks at arbitrary time scales is obtained. Moreover, the thickness distribution of the object at demanded axial planes can be obtained by numerical focusing. Our results show that the volume evolution of lipid domains follows approximately the same universal growth law of previously reported area evolution. However, the thickness of the domains does not alter significantly by time; therefore, the volume evolution is mostly attributed to the changes in area dynamics. These results might be useful in the field of membrane-based functional materials.

  13. Enforcing realizability in explicit multi-component species transport

    PubMed Central

    McDermott, Randall J.; Floyd, Jason E.

    2015-01-01

    We propose a strategy to guarantee realizability of species mass fractions in explicit time integration of the partial differential equations governing fire dynamics, which is a multi-component transport problem (realizability requires all mass fractions are greater than or equal to zero and that the sum equals unity). For a mixture of n species, the conventional strategy is to solve for n − 1 species mass fractions and to obtain the nth (or “background”) species mass fraction from one minus the sum of the others. The numerical difficulties inherent in the background species approach are discussed and the potential for realizability violations is illustrated. The new strategy solves all n species transport equations and obtains density from the sum of the species mass densities. To guarantee realizability the species mass densities must remain positive (semidefinite). A scalar boundedness correction is proposed that is based on a minimal diffusion operator. The overall scheme is implemented in a publicly available large-eddy simulation code called the Fire Dynamics Simulator. A set of test cases is presented to verify that the new strategy enforces realizability, does not generate spurious mass, and maintains second-order accuracy for transport. PMID:26692634

  14. Process for hydrogenation of hydrocarbon tars

    DOEpatents

    Dolbear, Geoffrey E.

    1978-07-18

    Hydrocarbon tars of high asphaltene content such as tars obtained from pyrolysis of coal are dissolved in a solvent formed from the hydrogenation of the coal tars, and the resultant mixture hydrogenated in the presence of a catalyst at a pressure from about 1500 to 5000 psig at a temperature from about 500.degree. F to about the critical temperature of the solvent to form a light hydrocarbon as a solvent for the tars. Hydrogen content is at least three times the amount of hydrogen consumed.

  15. Detonability of hydrocarbon fuels in air

    NASA Technical Reports Server (NTRS)

    Beeson, H. D.; Mcclenagan, R. D.; Bishop, C. V.; Benz, F. J.; Pitz, W. J.; Westbrook, C. K.; Lee, J. H. S.

    1991-01-01

    Studies were conducted of the detonation of gas-phase mixtures of n-hexane and JP-4, with oxidizers as varied as air and pure oxygen, measuring detonation velocities and cell sizes as a function of stoichiometry and diluent concentration. The induction length of a one-dimensional Zeldovich-von Neumann-Doering detonation was calculated on the basis of a theoretical model that employed the reaction kinetics of the hydrocarbon fuels used. Critical energy and critical tube diameter are compared for a relative measure of the heavy hydrocarbon fuels studied; detonation sensitivity appears to increase slightly with increasing carbon number.

  16. Catalysts for synthesizing various short chain hydrocarbons

    DOEpatents

    Colmenares, Carlos

    1991-01-01

    Method and apparatus (10), including novel photocatalysts, are disclosed for the synthesis of various short chain hydrocarbons. Light-transparent SiO.sub.2 aerogels doped with photochemically active uranyl ions (18) are fluidized in a fluidized-bed reactor (12) having a transparent window (16), by hydrogen and CO, C.sub.2 H.sub.4 or C.sub.2 H.sub.6 gas mixtures (20), and exposed to radiation (34) from a light source (32) external to the reactor (12), to produce the short chain hydrocarbons (36).

  17. Activation of hydrocarbons and the octane number

    NASA Technical Reports Server (NTRS)

    Peschard, Marcel

    1939-01-01

    This report presents an examination of the history of research on engine knocking and the various types of fuels used in the investigations of this phenomenon. According to this report, the spontaneous ignition of hydrocarbons doped with oxygen follows the logarithmic law within a certain temperature range, but not above 920 degrees K. Having extended the scope of investigations to prove hydrocarbons, the curves of the mixtures burned by air should then be established by progressive replacement of pure iso-octane with heptane. Pentane was also examined in this report.

  18. Incorporating hysteresis in a multi-phase multi-component NAPL modelling framework; a multi-component LNAPL gasoline example

    NASA Astrophysics Data System (ADS)

    Sookhak Lari, Kaveh; Davis, Greg B.; Johnston, Colin D.

    2016-10-01

    The longevity of chemicals in subsurface NAPL releases is a function of their partitioning into different phases. Hysteresis can affect distribution and partitioning of compounds in the vadose zone. We separated and modified hysteresis code from NAPL Simulator (which include hysteresis caused by fluid entrapment and capillary effects) and embedded it into TMVOC. For the first time, the resulting framework is used to model multi-component and multi-phase NAPL release, partitioning and transport. We then applied the verified framework to model effects of hysteresis on partitioning of BTEX, TMB and short and long chain alkanes from a typical gasoline spill. Excluding hysteresis resulted in an expanded LNAPL plume and underestimated the compounds longevity. Hysteresis altered the spatial distribution of LNAPL molar fractions as well as gas flow path and contaminants distribution compared to the non-hysteretic case. The amplifying effect of hysteresis on the longevity of mixtures (and associated risks) should be considered if non-hysteretic relationships are applied.

  19. Rate Limited Diffusion and Dissolution of Multicomponent Nonaqueous Phase Liquids (NAPLs) and Effects on Mass Discharge in Groundwater

    NASA Astrophysics Data System (ADS)

    Padgett, M.; Tick, G.; Carroll, K. C.

    2014-12-01

    Remediation efforts and contaminant transport predictions generally neglect the complicated dissolution and transport behavior associated with multicomponent NAPL (Non-aqueous phase liquid) sources. Therefore, it is important to understand the diffusion and dissolution processes occurring in these multicomponent systems as a function of mole fraction, molecular similarity/dissimilarity, hydraulic, or nonideal factors. A series of laboratory scale NAPL-aqueous phase dissolution experiments were conducted to assess dissolution and intra-NAPL diffusion as a function of multicomponent NAPL composition (i.e. mole fraction) for both trichloroethene and toluene. These target compounds were selected as representative contaminants as they are commonly components of NAPL mixtures and they define both classes of NAPL (dense-DNAPL and light-LNAPL). Predetermined volumes of target NAPL were mixed with an insoluble n-hexadecane NAPL to create mixtures that vary by NAPL composition. The ideality of resulting target compound dissolution was evaluated by quantifying NAPL-phase activity coefficient through Raoult's Law analysis. The results show that dissolution from the NAPL mixtures behave ideally for mole fractions above 0.2. As the target compound fraction of the NAPL mixture get smaller, the dissolution behavior becomes increasingly more nonideal (i.e. greater NAPL-phase activity coefficients). Overall, the time-series batch experiments show that dissolution rates were consistent for various mole fraction ratios, indicating that intra-NAPL diffusion is not the rate-limiting control over aqueous concentrations or is not significantly controlled by NAPL composition-dependent factors. The results of this work will improve transport predictions, remediation design, and risk assessments especially for sites contaminated by complex NAPL mixtures.

  20. Simulation of paraequilibrium growth in multicomponent systems

    NASA Astrophysics Data System (ADS)

    Ghosh, G.; Olson, G. B.

    2001-03-01

    A methodology to simulate paraequilibrium (PE) growth in multicomponent systems using the DIC-TRA (Diffusion-Controlled Transformation) software is presented. For any given multicomponent system containing substitutional and interstitial elements, the basic approach is to define a hypothetical element Z, whose thermodynamic and mobility parameters are expressed in terms of the weighted average (with respect to site fraction) of the thermodynamic parameters and mobilities of the substitutional alloying elements. This procedure facilitates the calculation of PE phase diagrams and the PE growth simulations directly in the Thermo-Calc and DICTRA software, respectively. The results of two distinct case studies in multicomponent alloys are presented. In the first example, we simulate the isothermal growth of PE cementite in an Fe-C-Co-Cr-Mo-Ni secondary hardening steel during tempering. This is of practical importance in modeling the carbide precipitation kinetics during secondary hardening. In the second example, we have presented the results of PE ferrite growth during continuous cooling from an intercritical temperature in an Fe-Al-C-Mn-Si low-alloy steel. This is of importance to the design of triple-phase steels containing an austenite that has optimum stability, to facilitate stress-induced transformation under dynamic loading. The results of both simulations are in good accord with experimental results. The model calculations do not consider any resistive or dissipative forces, such as the interfacial energy, strain energy, or solute drag, and, as a result, the interface velocities represent an upper limit under the available chemical driving force.

  1. MULTICOMPONENT REACTIONS IN ALKALOID-BASED DRUG DISCOVERY

    PubMed Central

    Magedov, I. V.; Kornienko, A.

    2016-01-01

    Multicomponent reactions are emerging as a powerful tool in alkaloid-based drug discovery. This Highlight describes several recent (all published in 2011) examples of the employment of multicomponent reactions for the synthesis of biologically active alkaloids and their medicinally relevant analogues. PMID:27917001

  2. A solid-state NMR method to determine domain sizes in multi-component polymer formulations

    NASA Astrophysics Data System (ADS)

    Schlagnitweit, Judith; Tang, Mingxue; Baias, Maria; Richardson, Sara; Schantz, Staffan; Emsley, Lyndon

    2015-12-01

    Polymer domain sizes are related to many of the physical properties of polymers. Here we present a solid-state NMR experiment that is capable of measuring domain sizes in multi-component mixtures. The method combines selective excitation of carbon magnetization to isolate a specific component with proton spin diffusion to report on domain size. We demonstrate the method in the context of controlled release formulations, which represents one of today's challenges in pharmaceutical science. We show that we can measure domain sizes of interest in the different components of industrial pharmaceutical formulations at natural isotopic abundance containing various (modified) cellulose derivatives, such as microcrystalline cellulose matrixes that are film-coated with a mixture of ethyl cellulose (EC) and hydroxypropyl cellulose (HPC).

  3. Humic acids-based one-step fabrication of SERS substrates for detection of polycyclic aromatic hydrocarbons.

    PubMed

    Qu, Lu-Lu; Li, Yuan-Ting; Li, Da-Wei; Xue, Jin-Qun; Fossey, John S; Long, Yi-Tao

    2013-03-07

    A facile one-step approach to fabricate substrates for surface-enhanced Raman scattering (SERS) detection of polycyclic aromatic hydrocarbons (PAHs) was explored by reduction of silver nitrate with humic acids (HAs). This simple process readily delivers silver nanoparticles (Ag NPs) decorated with HAs (HAs-Ag NPs), and an average diameter of 50 nm. More importantly, it compares favorably to Ag NPs prepared by the usual sodium citrate method, HAs-Ag NPs show excellent SERS activity for PAHs and display a remarkable capacity to absorb aromatic molecules through presumed π-π stacking interactions. Furthermore, the HAs-Ag NPs displayed good SERS stability, possibly due to the fact that HAs form loose coils or networks around the nanoparticles thus preventing aggregation. The investigation of qualitative and quantitative detection of PAHs on HAs-Ag NPs indicate that different PAHs can be distinguished easily from their discriminant SERS peaks, and the SERS responses exhibited a linear dependence on PAH concentrations over two orders of magnitude, with tens of nM detection limits. In addition, the HAs-Ag NPs performed well in the multicomponent analysis of PAH mixtures by the SERS technique without pre-separation.

  4. Lattice Boltzmann algorithm for continuum multicomponent flow

    NASA Astrophysics Data System (ADS)

    Halliday, I.; Hollis, A. P.; Care, C. M.

    2007-08-01

    We present a multicomponent lattice Boltzmann simulation for continuum fluid mechanics, paying particular attention to the component segregation part of the underlying algorithm. In the principal result of this paper, the dynamics of a component index, or phase field, is obtained for a segregation method after U. D’Ortona [Phys. Rev. E 51, 3718 (1995)], due to Latva-Kokko and Rothman [Phys. Rev. E 71 056702 (2005)]. The said dynamics accord with a simulation designed to address multicomponent flow in the continuum approximation and underwrite improved simulation performance in two main ways: (i) by reducing the interfacial microcurrent activity considerably and (ii) by facilitating simulational access to regimes of flow with a low capillary number and drop Reynolds number [I. Halliday, R. Law, C. M. Care, and A. Hollis, Phys. Rev. E 73, 056708 (2006)]. The component segregation method studied, used in conjunction with Lishchuk’s method [S. V. Lishchuk, C. M. Care, and I. Halliday, Phys. Rev. E 67, 036701 (2003)], produces an interface, which is distributed in terms of its component index; however, the hydrodynamic boundary conditions which emerge are shown to support the notion of a sharp, unstructured, continuum interface.

  5. Theory of margination in confined multicomponent suspensions

    NASA Astrophysics Data System (ADS)

    Henriquez Rivera, Rafael; Sinha, Kushal; Graham, Michael

    2015-11-01

    In blood flow, leukocytes and platelets tend to segregate near the vessel walls; this is known as margination. Margination of leukocytes and platelets is important in physiological processes, medical diagnostics and drug delivery. A mechanistic theory is developed to describe flow-induced segregation in confined multicomponent suspensions of deformable particles such as blood. The theory captures the essential features of margination by describing it in terms of two key competing processes in these systems at low Reynolds number: wall-induced migration and hydrodynamic pair collisions. The theory also includes the effect of physical properties of the deformable particles and molecular diffusion. Several regimes of segregation are identified, depending on the value of a ``margination parameter'' M. Moreover, there is a critical value of M below which a sharp ``drainage transition'' occurs: one component is completely depleted from the bulk flow to the vicinity of the walls. Direct hydrodynamic simulations also display this transition in suspensions where the components differ in size or flexibility. The developed mechanistic theory leads to substantial insight into the origins of margination and will help in guiding development of new technologies involving multicomponent suspensions. This work was supported by NSF grant CBET-1436082.

  6. Oxidation of biphenyl by a multicomponent enzyme system from Pseudomonas sp. strain LB400.

    PubMed Central

    Haddock, J D; Nadim, L M; Gibson, D T

    1993-01-01

    Pseudomonas sp. strain LB400 grows on biphenyl as the sole carbon and energy source. This organism also cooxidizes several chlorinated biphenyl congeners. Biphenyl dioxygenase activity in cell extract required addition of NAD(P)H as an electron donor for the conversion of biphenyl to cis-2,3-dihydroxy-2,3-dihydrobiphenyl. Incorporation of both atoms of molecular oxygen into the substrate was shown with 18O2. The nonlinear relationship between enzyme activity and protein concentration suggested that the enzyme is composed of multiple protein components. Ion-exchange chromatography of the cell extract gave three protein fractions that were required together to restore enzymatic activity. Similarities with other multicomponent aromatic hydrocarbon dioxygenases indicated that biphenyl dioxygenase may consist of a flavoprotein and iron-sulfur proteins that constitute a short electron transport chain involved in catalyzing the incorporation of both atoms of molecular oxygen into the aromatic ring. Images PMID:8419290

  7. Toxicity evaluation of PAH mixtures using Microtox

    SciTech Connect

    Thompkins, J.; Guthrie, E.; Pfaender, F.

    1995-12-31

    Polycyclic aromatic hydrocarbons (PAH) are produced from both natural and anthropogenic combustion processes. PAHs are known to be toxic and carcinogenic, are prevalent at many hazardous waste sites, and pose a potential risk to both ecological and human health. To date, few researchers have assessed the toxicity of polycyclic aromatic hydrocarbon (PAH) mixtures. The toxicity of chrysene, anthracene, pyrene, phenanthrene, fluoranthrene, acenaphthene, fluorene, and naphthalene were evaluated using Microtox, and acute toxicity assay that uses bioluminescent bacteria, Photobacterium phosphoreum, to measure toxicity. In this study, the toxicities of 2, 3, and 4 ring PAHs were determined for individual compounds. Synergistic or additive effects of PAH mixtures was assessed by comparing the toxicity of mixtures with that of pure compounds. Each PAH or mixture was evaluated at their respective water solubility concentrations, For individual PAHs tested, the toxicity of PAHs is inversely related to water solubility. Mixtures of two and three PAHs with disparate water solubilities resulted in synergistic interactions. Antagonistic interactions, a decrease in toxicity, were observed for mixtures of similar water solubilities.

  8. Mixtures Research at NIEHS: An Evolving Program

    PubMed Central

    Rider, Cynthia V; Carlin, Danielle J; DeVito, Micheal J; Thompson, Claudia L; Walker, Nigel J

    2014-01-01

    The National Institute of Environmental Health Sciences (NIEHS) has a rich history in evaluating the toxicity of mixtures. The types of mixtures assessed by the Division of the National Toxicology Program (DNTP) and the extramural community (through the Division of Extramural Research and Training (DERT)) have included a broad range of chemicals and toxicants, with each study having a unique set of questions and design considerations. Some examples of the types of mixtures studied include: groundwater contaminants, pesticides/fertilizers, dioxin-like chemicals (assessing the toxic equivalency approach), drug combinations, air pollution, metals, polycyclic aromatic hydrocarbons, technical mixtures (e.g. pentachlorophenol, flame retardants), and mixed entities (e.g. herbals, asbestos). These endeavors have provided excellent data on the toxicity of specific mixtures and have been informative to the human health risk assessment process in general (e.g. providing data on low dose exposures to environmental chemicals). However, the mixtures research effort at NIEHS, to date, has been driven by test article nominations to the DNTP or by investigator-initiated research through DERT. Recently, the NIEHS has embarked upon an effort to coordinate mixtures research across both intramural and extramural divisions in order to maximize mixtures research results. A path forward for NIEHS mixtures research will be based on feedback from a Request for Information (RFI) designed to gather up-to-date views on the knowledge gaps and roadblocks to evaluating mixtures and performing cumulative risk assessment, and a workshop organized to bring together mixtures experts from risk assessment, exposure science, biology, epidemiology, and statistics. The future of mixtures research at NIEHS will include projects from nominations to DNTP, studies by extramural investigators, and collaborations across government agencies that address high-priority questions in the field of mixtures research

  9. Mixtures research at NIEHS: an evolving program.

    PubMed

    Rider, Cynthia V; Carlin, Danielle J; Devito, Micheal J; Thompson, Claudia L; Walker, Nigel J

    2013-11-16

    The National Institute of Environmental Health Sciences (NIEHS) has a rich history in evaluating the toxicity of mixtures. The types of mixtures assessed by the Division of the National Toxicology Program (DNTP) and the extramural community (through the Division of Extramural Research and Training, DERT) have included a broad range of chemicals and toxicants, with each study having a unique set of questions and design considerations. Some examples of the types of mixtures studied include: groundwater contaminants, pesticides/fertilizers, dioxin-like chemicals (assessing the toxic equivalency approach), drug combinations, air pollution, metals, polycyclic aromatic hydrocarbons, technical mixtures (e.g., pentachlorophenol, flame retardants), and mixed entities (e.g., herbals, asbestos). These endeavors have provided excellent data on the toxicity of specific mixtures and have been informative to the human health risk assessment process in general (e.g., providing data on low dose exposures to environmental chemicals). However, the mixtures research effort at NIEHS, to date, has been driven by test article nominations to the DNTP or by investigator-initiated research through DERT. Recently, the NIEHS has embarked upon an effort to coordinate mixtures research across both intramural and extramural divisions in order to maximize mixtures research results. A path forward for NIEHS mixtures research will be based on feedback from a Request for Information (RFI) designed to gather up-to-date views on the knowledge gaps and roadblocks to evaluating mixtures and performing cumulative risk assessment, and a workshop organized to bring together mixtures experts from risk assessment, exposure science, biology, epidemiology, and statistics. The future of mixtures research at NIEHS will include projects from nominations to DNTP, studies by extramural investigators, and collaborations across government agencies that address high-priority questions in the field of mixtures research.

  10. Profiling refined hydrocarbon fuels using polar components

    USGS Publications Warehouse

    Rostad, C.E.; Hostettler, F.D.

    2007-01-01

    Identification of a fuel released into the environment can be difficult due to biodegradation or weathering. Negative electrospray ionization/mass spectrometry was used to screen for unique polar components in a wide variety of commercial hydrocarbon products and mixtures. These fuels produced unique and relatively simple spectra. When applied to hydrocarbon samples from a large, long-term fuel spill in a relatively cool climate in which the alkane, isoprenoid, and alkylcyclohexane portions had begun to biodegrade or weather, the polar components in these samples had changed little over time. This technique provided rapid fuel identification on hydrocarbons released into the environment, without sample preparation, fractionation, or chromatography. Copyright ?? Taylor & Francis Group, LLC.

  11. Method and apparatus for synthesizing hydrocarbons

    DOEpatents

    Colmenares, C.A.; Somorjai, G.A.; Maj, J.J.

    1983-06-21

    A method and apparatus for synthesizing a mixture of hydrocarbons having five carbons or less is disclosed. An equal molar ratio of CO and H/sub 2/ gases is caused to pass through a ThO/sub 2/ catalyst having a surface area of about 80 to 125 m/sup 2//g. The catalyst further includes Na present as a substitutional cation in an amount of about 5 to 10 atom %. At a temperature of about 340 to 360/sup 0/C, and at pressures of about 20 to 50 atm, CH/sub 3/OH is produced in an amount of about 90 wt % of the total hydrocarbon mixture, and comprised 1 mole % of the effluent gas.

  12. Hydrogen Production from Liquid Hydrocarbons Demonstration Program.

    DTIC Science & Technology

    1986-09-01

    to naphtha . These hydrogen plant feedstocks have nil sulfur content. End uses for hydrogen include ammonia and methanol manufacture, hydrocracking...steam reformer (HTSR) to convert approximately 55% of the carbon content of the feed logistic fuel to oxides of carbon (carbon monoxide and carbon dioxide...and (2), an autothermal reformer (ATR) to convert the remainder of the hydrocarbon feedstock to a mixture of hydrogen and carbon oxides. Other

  13. Process for the solvent deasphalting of asphaltene containing hydrocarbons

    SciTech Connect

    Ikematsu, M.; Honzyo, I.; Sakai, K.

    1985-04-30

    A process for the solvent deasphalting of asphaltene-containing hydrocarbons which comprising mixing asphaltene-containing hydrocarbons with a metal compound such as aluminum sulfate or titanium (IV) oxide and also with a solvent such as n-heptane, n-hexane, n-heptane or a mixed n-pentane.n-butanol solvent, to form a mixture which is then allowed to stand still to precipitate and separate the asphaltene therefrom thereby obtaining a deasphalted oil.

  14. Process for the solvent deasphalting of asphaltene-containing hydrocarbons

    SciTech Connect

    Ikematsu, M.; Honzyo, I.; Sakai, K.

    1985-06-25

    A process for the solvent deasphalting of asphaltene-containing hydrocarbons which comprising mixing asphaltene-containing hydrocarbons with a metal compound such as aluminum carbonates or titanium (IV) oxide and also with a solvent such as n-heptane, n-hexane, n-heptane or a mixed n-pentane.n-butanol solvent, to form a mixture which is then allowed to stand still to precipitate and separate the asphaltene therefrom thereby obtaining a deasphalted oil.

  15. Basic Considerations in the Combustion of Hydrocarbon Fuels with Air

    NASA Technical Reports Server (NTRS)

    Barnett, Henry C; Hibbard, Robert R

    1957-01-01

    Basic combustion research is collected, collated, and interpreted as it applies to flight propulsion. The following fundamental processes are treated in separate chapters: atomization and evaporation of liquid fuels, flow and mixing processes in combustion chambers, ignition and flammability of hydrocarbon fuels, laminar flame propagation, turbulent flames, flame stabilization, diffusion flames, oscillations in combustors, and smoke and coke formation in the combustion of hydrocarbon-air mixtures. Theoretical background, basic experimental data, and practical significance to flight propulsion are presented.

  16. On thermal conductivity of gas mixtures containing hydrogen

    NASA Astrophysics Data System (ADS)

    Zhukov, Victor P.; Pätz, Markus

    2016-12-01

    A brief review of formulas used for the thermal conductivity of gas mixtures in CFD simulations of rocket combustion chambers is carried out in the present work. In most cases, the transport properties of mixtures are calculated from the properties of individual components using special mixing rules. The analysis of different mixing rules starts from basic equations and ends by very complex semi-empirical expressions. The formulas for the thermal conductivity are taken for the analysis from the works on modelling of rocket combustion chambers. H_2- O_2 mixtures are chosen for the evaluation of the accuracy of the considered mixing rules. The analysis shows that two of them, of Mathur et al. (Mol Phys 12(6):569-579, 1967), and of Mason and Saxena (Phys Fluids 1(5):361-369, 1958), have better agreement with the experimental data than other equations for the thermal conductivity of multicomponent gas mixtures.

  17. Multi-component seismic modeling and robust pre-stack seismic waveform inversion for elastic anisotropic media parameters

    NASA Astrophysics Data System (ADS)

    Li, Tao

    Consideration of azimuthal anisotropy, at least to an orthorhombic symmetry is important in exploring the naturally fractured and unconventional hydrocarbon reservoirs. Full waveform inversion of multicomponent seismic data can, in principle, provide more robust estimates of subsurface elastic parameters and density than the inversion of single component (P wave) seismic data. In addition, azimuthally dependent anisotropy can only be resolved by carefully studying the multicomponent seismic displacement data acquired and processed along different azimuths. Such an analysis needs an inversion algorithm capable of simultaneously optimizing multiple objectives, one for each data component along each azimuth. In this dissertation, I propose a novel multiobjective methodology using a parallelized version of NSGA II for waveform inversion of multicomponent seismic data along two azimuths. The proposed methodology is also an improvement of the original NSGA II in overall computational efficiency, preservation of population diversity, and rapid sampling of the model space. Next, the proposed methodology is applied on wide azimuth and multicomponent vertical seismic profile (VSP) data to provide reliable estimation of subsurface anisotropy at and near the well location. Prestack waveform inversion was applied to the wide-azimuth multicomponent VSP data acquired at the Wattenberg Field, located in Denver Basin of northeastern Colorado, USA, to characterize the Niobrara formation for azimuthal anisotropy. By comparing the waveform inversion results with an independent study that used a joint slowness-polarization approach to invert the same data, we conclude that the waveform inversion is a reliable tool for inverting the wide-azimuth multicomponent VSP data for anisotropy estimation. Last but not least, an anisotropic elastic three-dimensional scheme for modeling the elastodynamic wavefield is developed in order to go beyond the 1D layering assumption being used in previous

  18. Biofiltration of gasoline and diesel aliphatic hydrocarbons.

    PubMed

    Halecky, Martin; Rousova, Jana; Paca, Jan; Kozliak, Evguenii; Seames, Wayne; Jones, Kim

    2015-02-01

    The ability of a biofilm to switch between the mixtures of mostly aromatic and aliphatic hydrocarbons was investigated to assess biofiltration efficiency and potential substrate interactions. A switch from gasoline, which consisted of both aliphatic and aromatic hydrocarbons, to a mixture of volatile diesel n-alkanes resulted in a significant increase in biofiltration efficiency, despite the lack of readily biodegradable aromatic hydrocarbons in the diesel mixture. This improved biofilter performance was shown to be the result of the presence of larger size (C₉-C(12)) linear alkanes in diesel, which turned out to be more degradable than their shorter-chain (C₆-C₈) homologues in gasoline. The evidence obtained from both biofiltration-based and independent microbiological tests indicated that the rate was limited by biochemical reactions, with the inhibition of shorter chain alkane biodegradation by their larger size homologues as corroborated by a significant substrate specialization along the biofilter bed. These observations were explained by the lack of specific enzymes designed for the oxidation of short-chain alkanes as opposed to their longer carbon chain homologues.

  19. Gauge transformation and symmetries of the commutative multicomponent BKP hierarchy

    NASA Astrophysics Data System (ADS)

    Li, Chuanzhong

    2016-01-01

    In this paper, we defined a new multi-component B type Kadomtsev-Petviashvili (BKP) hierarchy that takes values in a commutative subalgebra of {gl}(N,{{C}}). After this, we give the gauge transformation of this commutative multicomponent BKP (CMBKP) hierarchy. Meanwhile, we construct a new constrained CMBKP hierarchy that contains some new integrable systems, including coupled KdV equations under a certain reduction. After this, the quantum torus symmetry and quantum torus constraint on the tau function of the commutative multi-component BKP hierarchy will be constructed.

  20. Multicomponent Reactions, Union of MCRs and Beyond.

    PubMed

    Zarganes-Tzitzikas, Tryfon; Chandgude, Ajay L; Dömling, Alexander

    2015-10-01

    Multicomponent reactions (MCRs), which are located between one- and two-component and polymerization reactions, provide a number of valuable conceptual and synthetic advantages over stepwise sequential approaches towards complex and valuable molecules. To address current limitations in the number of MCRs and the resulting scaffolds, the concept of union of MCRs was introduced two decades ago by Dömling and Ugi and is rapidly advancing, as is apparent by several recently published works. MCR technology is now widely recognized for its impact on drug discovery projects and is strongly endorsed by industry in addition to academia. Clearly, novel scaffolds accessible in few steps including MCRs will further enhance the field of applications. Additionally, broad expansion of MCR applications in fields such as imaging, materials science, medical devices, agriculture, or futuristic applications in stem cell therapy and theragnostics or solar energy and superconductivity are predicted.

  1. Oximetry of retinal capillaries by multicomponent analysis.

    PubMed

    Furukawa, Hiromitsu; Arimoto, Hidenobu; Shirai, Tomohiro; Ooto, Sotaro; Hangai, Masanori; Yoshimura, Nagahisa

    2012-08-01

    Retinal oximetry of capillaries was performed for early detection of retinal vascular abnormalities, which are caused predominantly by complications of systemic circulatory diseases. As the conventional method for determining absorbance is not applicable to capillaries, multicomponent analysis was used to estimate the absorbance spectra of the retinal blood vessels. In this analysis, the capillary spectrum was classified as intermediate between those of the retinal arteries and veins, enabling relative estimation of oxygen saturation in the capillaries. This method could be useful for early recognition of disturbances in the peripheral circulation. Furthermore, a spectroscopic ophthalmoscope system based on the proposed method was developed to examine the human retina. A clinical trial of this system demonstrated that oximetry of the retinal capillaries may be an improvement over the present diagnosis for patients of malignant hypertension.

  2. Simulations of Evaporating Multicomponent Fuel Drops

    NASA Technical Reports Server (NTRS)

    Bellan, Josette; Le Clercq, Patrick

    2005-01-01

    A paper presents additional information on the subject matter of Model of Mixing Layer With Multicomponent Evaporating Drops (NPO-30505), NASA Tech Briefs, Vol. 28, No. 3 (March 2004), page 55. To recapitulate: A mathematical model of a three-dimensional mixing layer laden with evaporating fuel drops composed of many chemical species has been derived. The model is used to perform direct numerical simulations in continuing studies directed toward understanding the behaviors of sprays of liquid petroleum fuels in furnaces, industrial combustors, and engines. The model includes governing equations formulated in an Eulerian and a Lagrangian reference frame for the gas and drops, respectively, and incorporates a concept of continuous thermodynamics, according to which the chemical composition of a fuel is described by use of a distribution function. In this investigation, the distribution function depends solely on the species molar weight. The present paper reiterates the description of the model and discusses further in-depth analysis of the previous results as well as results of additional numerical simulations assessing the effect of the mass loading. The paper reiterates the conclusions reported in the cited previous article, and states some new conclusions. Some new conclusions are: 1. The slower evaporation and the evaporation/ condensation process for multicomponent-fuel drops resulted in a reduced drop-size polydispersity compared to their single-component counterpart. 2. The inhomogeneity in the spatial distribution of the species in the layer increases with the initial mass loading. 3. As evaporation becomes faster, the assumed invariant form of the molecular- weight distribution during evaporation becomes inaccurate.

  3. Effect of deoxygenation and prestressing on hydrocarbon fuel thermal stability

    NASA Technical Reports Server (NTRS)

    Bittker, D. A.

    1983-01-01

    A jet fuel thermal oxidation tester was used to study the effect of deoxygenation and deoxygenated prestressing on deposit formation when hydrocarbon fuels are thermally stressed. Four pure hydrocarbons (n-decane, cyclohexane, benzene and 1-hexene) and two mixtures (10 percent tetralin in n-dodecane and commercial Jet A) were used at temperatures of 250 C to 400 C. Deoxygenation decreased deposit formation for cycloheaxane but increased it for benzene. Deoxygenation decreased deposit formation for the two fuel mixtures at 250 C but had no effect at 350 C. Deoxygenated prestressing either increased or decreased deposit formation depending on the fuel used and the temperature.

  4. Theory of dynamic arrest in colloidal mixtures

    NASA Astrophysics Data System (ADS)

    Juárez-Maldonado, R.; Medina-Noyola, M.

    2008-05-01

    We present a first-principles theory of dynamic arrest in colloidal mixtures based on the multicomponent self-consistent generalized Langevin equation theory of colloid dynamics [M. A. Chávez-Rojo and M. Medina-Noyola, Phys. Rev. E 72, 031107 (2005); M. A. Chávez-Rojo and M. Medina-Noyola, Phys. Rev. E76, 039902 (2007)]. We illustrate its application with a description of dynamic arrest in two simple model colloidal mixtures: namely, hard-sphere and repulsive Yukawa binary mixtures. Our results include observation of the two patterns of dynamic arrest, one in which both species become simultaneously arrested and the other involving the sequential arrest of the two species. The latter case gives rise to mixed states in which one species is arrested while the other species remains mobile. We also derive the (”bifurcation” or fixed-point”) equations for the nonergodic parameters of the system, which takes the surprisingly simple form of a system of coupled equations for the localization length of the particles of each species. The solution of this system of equations indicates unambiguously which species is arrested (finite localization length) and which species remains ergodic (infinite localization length). As a result, we are able to draw the entire ergodic-nonergodic phase diagram of the binary hard-sphere mixture.

  5. Coal-water mixture fuel burner

    DOEpatents

    Brown, T.D.; Reehl, D.P.; Walbert, G.F.

    1985-04-29

    The present invention represents an improvement over the prior art by providing a rotating cup burner arrangement for use with a coal-water mixture fuel which applies a thin, uniform sheet of fuel onto the inner surface of the rotating cup, inhibits the collection of unburned fuel on the inner surface of the cup, reduces the slurry to a collection of fine particles upon discharge from the rotating cup, and further atomizes the fuel as it enters the combustion chamber by subjecting it to the high shear force of a high velocity air flow. Accordingly, it is an object of the present invention to provide for improved combustion of a coal-water mixture fuel. It is another object of the present invention to provide an arrangement for introducing a coal-water mixture fuel into a combustion chamber in a manner which provides improved flame control and stability, more efficient combustion of the hydrocarbon fuel, and continuous, reliable burner operation. Yet another object of the present invention is to provide for the continuous, sustained combustion of a coal-water mixture fuel without the need for a secondary combustion source such as natural gas or a liquid hydrocarbon fuel. Still another object of the present invention is to provide a burner arrangement capable of accommodating a coal-water mixture fuel having a wide range of rheological and combustion characteristics in providing for its efficient combustion. 7 figs.

  6. MPH: A library for distributed multi-component environment

    SciTech Connect

    Ding, Chris H.Q.; He, Yun

    2001-06-01

    Many current large and complex HPC applications are based on semi-independent program components developed by different groups or for different purposes. On distributed memory parallel supercomputers, how to perform component-name registration and initialize communications between independent components are among the first critical steps in establishing a distributed multi-component environment. Here we describe MPH, a multi-component handshaking library that resolves these tasks in a convenient and consistent way. MPH uses MPI for high performance and supports many PVM functionality. It supports two major parallel integration mechanism: multi-component multi-executable (MCME) and multi-component single-executable (MCME). It is a simple, easy-to-use module for developing practical codes, or as basis for larger software tools/frameworks.

  7. Erbium triflate promoted multicomponent synthesis of highly substituted imidazoles.

    PubMed

    Rajaguru, Kandasamy; Suresh, Rajendran; Mariappan, Arumugam; Muthusubramanian, Shanmugam; Bhuvanesh, Nattamai

    2014-02-07

    The synthesis of highly substituted imidazole derivatives has been achieved from various α-azido chalcones, aryl aldehydes, and anilines. This multicomponent protocol employs erbium triflate as a catalyst resulting in excellent yield of the imidazoles.

  8. MICROWAVE-ACCELERATED MULTICOMPONENT REACTIONS UNDER SOLVENT-FREE CONDITIONS

    EPA Science Inventory

    The application of microwave-accelerated solventless synthetic protocols in multicomponent (MCC) reactions will be exemplified by several condensation and cyclization reactions including the rapid one-pot assembly of valuable heterocyclic compounds from in situ generated intermed...

  9. Multicomponent cascade reactions of unprotected carbohydrates and amino acids.

    PubMed

    Voigt, Benjamin; Linke, Michael; Mahrwald, Rainer

    2015-06-05

    Herein an operationally simple multicomponent reaction of unprotected carbohydrates with amino acids and isonitriles is presented. By the extension of this Ugi-type reaction to an unprotected disaccharide a novel glycopeptide structure was accessible.

  10. Multiscale simulation of ideal mixtures using smoothed dissipative particle dynamics

    NASA Astrophysics Data System (ADS)

    Petsev, Nikolai D.; Leal, L. Gary; Shell, M. Scott

    2016-02-01

    Smoothed dissipative particle dynamics (SDPD) [P. Español and M. Revenga, Phys. Rev. E 67, 026705 (2003)] is a thermodynamically consistent particle-based continuum hydrodynamics solver that features scale-dependent thermal fluctuations. We obtain a new formulation of this stochastic method for ideal two-component mixtures through a discretization of the advection-diffusion equation with thermal noise in the concentration field. The resulting multicomponent approach is consistent with the interpretation of the SDPD particles as moving volumes of fluid and reproduces the correct fluctuations and diffusion dynamics. Subsequently, we provide a general multiscale multicomponent SDPD framework for simulations of molecularly miscible systems spanning length scales from nanometers to the non-fluctuating continuum limit. This approach reproduces appropriate equilibrium properties and is validated with simulation of simple one-dimensional diffusion across multiple length scales.

  11. Kinetic Method for Hydrogen-Deuterium-Tritium Mixture Distillation Simulation

    SciTech Connect

    Sazonov, A.B.; Kagramanov, Z.G.; Magomedbekov, E.P.

    2005-07-15

    Simulation of hydrogen distillation plants requires mathematical procedures suitable for multicomponent systems. In most of the present-day simulation methods a distillation column is assumed to be composed of theoretical stages, or plates. However, in the case of a multicomponent mixture theoretical plate does not exist.An alternative kinetic method of simulation is depicted in the work. According to this method a system of mass-transfer differential equations is solved numerically. Mass-transfer coefficients are estimated with using experimental results and empirical equations.Developed method allows calculating the steady state of a distillation column as well as its any non-steady state when initial conditions are given. The results for steady states are compared with ones obtained via Thiele-Geddes theoretical stage technique and the necessity of using kinetic method is demonstrated. Examples of a column startup period and periodic distillation simulations are shown as well.

  12. Multicomponent reactions: A simple and efficient route to heterocyclic phosphonates

    PubMed Central

    2016-01-01

    Summary Multicomponent reactions (MCRs) are one of the most important processes for the preparation of highly functionalized organic compounds in modern synthetic chemistry. As shown in this review, they play an important role in organophosphorus chemistry where phosphorus reagents are used as substrates for the synthesis of a wide range of phosphorylated heterocycles. In this article, an overview about multicomponent reactions used for the synthesis of heterocyclic compounds bearing a phosphonate group on the ring is given. PMID:27559377

  13. A Weibull characterization for tensile fracture of multicomponent brittle fibers

    NASA Technical Reports Server (NTRS)

    Barrows, R. G.

    1977-01-01

    A statistical characterization for multicomponent brittle fibers in presented. The method, which is an extension of usual Weibull distribution procedures, statistically considers the components making up a fiber (e.g., substrate, sheath, and surface) as separate entities and taken together as in a fiber. Tensile data for silicon carbide fiber and for an experimental carbon-boron alloy fiber are evaluated in terms of the proposed multicomponent Weibull characterization.

  14. Modulated decay in the multi-component Universe

    SciTech Connect

    Enomoto, Seishi; Kohri, Kazunori; Matsuda, Tomohiro E-mail: kohri@post.kek.jp

    2013-08-01

    The early Universe after inflation may have oscillations, kinations (nonoscillatory evolution of a field), topological defects, relativistic and non-relativistic particles at the same time. The Universe whose energy density is a sum of those components can be called the multi-component Universe. The components, which may have distinguishable density scalings, may decay modulated. In this paper we study generation of the curvature perturbations caused by the modulated decay in the multi-component Universe.

  15. Polycyclic aromatic hydrocarbons in carcinogenesis.

    PubMed Central

    Warshawsky, D

    1999-01-01

    A symposium on "Polycyclic Aromatic Hydrocarbons (PAHs) in Carcinogenesis" was presented at the third International Congress of Pathophysiology held in Lathi, Finland, 28 June-3 July 1998. The congress was also sponsored by the International Union of Biological Sciences and the International Society of Free Radical Research. Institutional support for the symposium included the Electric Power Research Institute, National Center for Toxicological Research, and EPA/National Health and Environmental Effects Research Laboratory and the Office of Solid Waste and Emergency Response. The symposium focused on the sources, carcinogenicity, genotoxicity, and risk assessment of individual and mixtures of PAHs that are found in solid wastes, Superfund sites, and other hazardous waste sites. Based on the occurrence of PAHs at numerous Superfund sites and the significant data gaps on the toxic potential of certain PAHs, the information developed during this symposium would be of value in assessing health risks of these chemicals at Superfund and other hazardous waste sites. PMID:10090712

  16. Expanding Conventional Seismic Stratigrphy into the Multicomponent Seismic Domain

    SciTech Connect

    Innocent Aluka

    2008-08-31

    Multicomponent seismic data are composed of three independent vector-based seismic wave modes. These wave modes are, compressional mode (P), and shear modes SV and SH. The three modes are generated using three orthogonal source-displacement vectors and then recorded using three orthogonal vector sensors. The components travel through the earth at differing velocities and directions. The velocities of SH and SV as they travel through the subsurface differ by only a few percent, but the velocities of SV and SH (Vs) are appreciably lower than the P-wave velocity (Vp). The velocity ratio Vp/Vs varies by an order of magnitude in the earth from a value of 15 to 1.5 depending on the degree of sedimentary lithification. The data used in this study were acquired by nine-component (9C) vertical seismic profile (VSP), using three orthogonal vector sources. The 9C vertical seismic profile is capable of generating P-wave mode and the fundamental S-wave mode (SH-SH and SV-SV) directly at the source station and permits the basic components of elastic wavefield (P, SH-SH and SV-SV) to be separated from one another for the purposes of imaging. Analysis and interpretations of data from the study area show that incident full-elastic seismic wavefield is capable of reflecting four different wave modes, P, SH , SV and C which can be utilized to fully understand the architecture and heterogeneities of geologic sequences. The conventional seismic stratigraphy utilizes only reflected P-wave modes. The notation SH mode is the same as SH-SH; SV mode means SV-SV and C mode which is a converted shear wave is a special SV mode and is the same as P-SV. These four wave modes image unique geologic stratigraphy and facies and at the same time reflect independent stratal surfaces because of the unique orientation of their particle-displacement vectors. As a result of the distinct orientation of individual mode's particle-displacement vector, one mode may react to a critical subsurface sequence more

  17. Hydrocarbon degradation by antarctic bacteria

    SciTech Connect

    Cavanagh, J.A.E.; Nichols, P.D.; McMeekin, T.A.; Franzmann, P.D.

    1996-12-31

    Bacterial cultures obtained from sediment samples collected during a trial oil spill experiment conducted at Airport beach, Eastern Antarctica were selectively enriched for n-alkane-degrading and phenanthrenedegrading bacteria. Samples were collected from a control site and sites treated with different hydrocarbon mixtures - Special Antarctic blend (SAB), BP-Visco and orange roughy oils. One set of replicate sites was also treated with water from Organic Lake which had previously been shown to contain hydrocarbon-degrading bacteria. No viable bacteria were obtained from samples collected from sites treated with orange roughy oil. Extensive degradation of n-alkanes by enrichment cultures obtained from sites treated with SAB and BP-Visco occurred at both 25{degrees}C and 10{degrees}C. Extensive degradation of phenanthrene also occurred in enrichment cultures from these sites grown at 25{degrees}C. Concurrent increases of polar lipid in these cultures were also observed. The presence of 1,4-naphthaquinone and 1-naphthol during the growth of the cultures on phenanthrene is unusual and warrants further investigation of the mechanism of phenanthrene-degradation by these Antarctic bacteria.

  18. Method for direct production of carbon disulfide and hydrogen from hydrocarbons and hydrogen sulfide feedstock

    SciTech Connect

    Miao, Frank Q.; Erekson, Erek James

    1998-12-01

    A method for converting hydrocarbons and hydrogen sulfide to carbon disulfide and hydrogen is provided comprising contacting the hydrocarbons and hydrogen sulfide to a bi-functional catalyst residing in a controlled atmosphere for a time and at a temperature sufficient to produce carbon disulfide and hydrogen. Also provided is a catalyst for converting carbon sulfides and hydrogen sulfides to gasoline range hydrocarbons comprising a mixture containing a zeolite catalyst and a hydrogenating catalyst.

  19. Quantitative analysis of povidone (PVP) in drug-PVP matrix using multicomponent analysis.

    PubMed

    Pedersen, G; Kristensen, H G

    1999-01-01

    A method for the quantification of povidone (PVP), in solid dispersions and physical mixtures of the polymer and a very slightly soluble drug substance, has been developed by multicomponent analysis using the concepts of chemometrics. Because the UV-absorbance spectra of PVP is completely overlapped by the UV-absorbance spectra of the drug substance, a direct spectrophotometric method of PVP is impossible. However, UV-spectrophotometric data were analyzed by the Quant + Perkin Elmer software for quantitative multicomponent analysis using chemometrics, and by the optimal method developed using a solvent of pH 7.4, a fast, reliable, and precise detection of PVP was obtained when the content of PVP in the powder sample exceeded 20% (m/m). Two methods were developed by the calibration procedure, using buffers of pH 7.4, respectively pH 8.5. By applying a solvent of pH 8.5, more sample could be taken into use because of the enhanced solubility of the drug substance, and hence it was believed that as more PVP was taken into use, a better prediction of PVP would be obtained. However, as more drug substance was taken into use the UV-absorbance spectrum of PVP was even more overlapped, and an inferior prediction was obtained.

  20. Catalysts and process for liquid hydrocarbon fuel production

    SciTech Connect

    White, Mark G.; Ranaweera, Samantha A.; Henry, William P.

    2016-08-02

    The present invention provides a novel process and system in which a mixture of carbon monoxide and hydrogen synthesis gas, or syngas, is converted into hydrocarbon mixtures composed of high quality distillates, gasoline components, and lower molecular weight gaseous olefins in one reactor or step. The invention utilizes a novel supported bimetallic ion complex catalyst for conversion, and provides methods of preparing such novel catalysts and use of the novel catalysts in the process and system of the invention.

  1. IUPAC-NIST Solubility Data Series. 90. Hydroxybenzoic Acid Derivatives in Binary, Ternary, and Multicomponent Systems. Part I. Hydroxybenzoic Acids, Hydroxybenzoates, and Hydroxybenzoic Acid Salts in Water and Aqueous Systems

    NASA Astrophysics Data System (ADS)

    Goto, Rensuke; Fukuda, Hiroshi; Königsberger, Erich; Königsberger, Lan-Chi

    2011-03-01

    The solubility data for well-defined binary, ternary, and multicomponent systems of solid-liquid type are reviewed. One component, which is 2-, 3-, and 4-hydroxybenzoic acids, 4-hydroxybenzoate alkyl esters (parabens), or hydroxybenzoic acid salts, is in the solid state at room temperature and another component is liquid water, meaning that all of the systems are aqueous solutions. The ternary or multicomponent systems include organic substances of various classes (hydrocarbons of several structural types, halogenated hydrocarbons, alcohols, acids, ethers, esters, amides, and surfactants) or inorganic substances. Systems reported in the primary literature from 1898 through 2000 are compiled. For seven systems, sufficient binary data for hydroxybenzoic acids or parabens in water are available to allow critical evaluation. Almost all data are expressed as mass and mole fractions as well as the originally reported units, while some data are expressed as molar concentration.

  2. Hydrocarbon Spectral Database

    National Institute of Standards and Technology Data Gateway

    SRD 115 Hydrocarbon Spectral Database (Web, free access)   All of the rotational spectral lines observed and reported in the open literature for 91 hydrocarbon molecules have been tabulated. The isotopic molecular species, assigned quantum numbers, observed frequency, estimated measurement uncertainty and reference are given for each transition reported.

  3. Oxygenated Derivatives of Hydrocarbons

    Technology Transfer Automated Retrieval System (TEKTRAN)

    For the book entitled “Insect Hydrocarbons: Biology, Biochemistry and Chemical Ecology”, this chapter presents a comprehensive review of the occurrence, structure and function of oxygenated derivatives of hydrocarbons. The book chapter focuses on the occurrence, structural identification and functi...

  4. Recovering hydrocarbons from hydrocarbon-containing vapors

    DOEpatents

    Mirza, Zia I.; Knell, Everett W.; Winter, Bruce L.

    1980-09-30

    Values are recovered from a hydrocarbon-containing vapor by contacting the vapor with quench liquid consisting essentially of hydrocarbons to form a condensate and a vapor residue, the condensate and quench fluid forming a combined liquid stream. The combined liquid stream is mixed with a viscosity-lowering liquid to form a mixed liquid having a viscosity lower than the viscosity of the combined liquid stream to permit easy handling of the combined liquid stream. The quench liquid is a cooled portion of the mixed liquid. Viscosity-lowering liquid is separated from a portion of the mixed liquid and cycled to form additional mixed liquid.

  5. Plant hydrocarbon recovery process

    SciTech Connect

    Dzadzic, P.M.; Price, M.C.; Shih, C.J.; Weil, T.A.

    1982-01-26

    A process for production and recovery of hydrocarbons from hydrocarbon-containing whole plants in a form suitable for use as chemical feedstocks or as hydrocarbon energy sources which process comprises: (A) pulverizing by grinding or chopping hydrocarbon-containing whole plants selected from the group consisting of euphorbiaceae, apocynaceae, asclepiadaceae, compositae, cactaceae and pinaceae families to a suitable particle size, (B) drying and preheating said particles in a reducing atmosphere under positive pressure (C) passing said particles through a thermal conversion zone containing a reducing atmosphere and with a residence time of 1 second to about 30 minutes at a temperature within the range of from about 200* C. To about 1000* C., (D) separately recovering the condensable vapors as liquids and the noncondensable gases in a condition suitable for use as chemical feedstocks or as hydrocarbon fuels.

  6. Subsea hydrocarbon sensor system

    SciTech Connect

    Marosko, R.J.; Warren, W.B.

    1981-08-04

    A hydrocarbon detection system is provided for use in a subsea hydrocarbon production installation which includes production tree assemblies, an electro-hydraulic control module located on the sea floor and remote from the production trees, cable assemblies interconnecting the control module with the production trees through magnetic coupling devices. A pair of inductive elements are electrically coupled by the surrounding sea water. Displacement of the conductive sea water by escaping hydrocarbons affects the coupling between the inductive elements to produce a hydrocarbon-presence-responsive output signal. The inductive elements are resonated within a selected frequency range by capacitors coupled with a primary inductor coil by auxiliary windings on a common core element. An excitation signal sweeps over the selected frequency range at a rate effective to produce a peak detected signal at the resonant frequency. The peak output signal is then monitored to form a control signal functionally related to the presence or absence of hydrocarbons in the sea water.

  7. Gas adsorption and gas mixture separations using mixed-ligand MOF material

    DOEpatents

    Hupp, Joseph T.; Mulfort, Karen L.; Snurr, Randall Q.; Bae, Youn-Sang

    2011-01-04

    A method of separating a mixture of carbon dioxiode and hydrocarbon gas using a mixed-ligand, metal-organic framework (MOF) material having metal ions coordinated to carboxylate ligands and pyridyl ligands.

  8. MIXTURES OF THYROID DISRUPTING CHEMICALS: TESTING ADDITIVITY OF HEPATIC INDUCERS AND THYROID PEROXIDASE INHIBITORS.

    EPA Science Inventory

    Humans are exposed to chemical mixtures via diet, occupation, and the environment. Previous data demonstrated that low doses of polycyclic halogenated aromatic hydrocarbons (PHAHs) acting through similar mechanisms result in an additive reduction of thyroxine (T4). If xenobioti...

  9. Tools for efficient design of multicomponent separation processes

    NASA Astrophysics Data System (ADS)

    Huff, Joshua Lee

    Separations account for as much as 85% of plant operating costs in chemical production; it is therefore important that they be designed with energy efficiency in mind. This can only be achieved if two things are achieved: the complete space of design options is known, and an accurate way is developed to compare all possible design options. For both membrane separation cascades and multicomponent distillation configurations, this dissertation explores methods for designing energy efficient separations. The operating cost of membranes used in production of nitrogen gas from air is largely driven by the compressors required to maintain a pressure differential. Optimization of the total compressor duty can reveal an ideal cascade arrangement and set of operating conditions for a given feed and recovery. With this optimization technique in hand, it is then possible to examine the effect of introducing extra stages to form intermediate stage cascades. Furthermore, the effect of varying the recovery of the nitrogen stream can be examined to discover a U-shaped relationship between recovery and energy requirement. Conventional distillation configurations use n -- 1 distillation columns to separate a multicomponent feed mixture into pure products. Past research has identified a way to quickly and algorithmically generate the complete ranklist of regular-column configurations using an integer programming formulation called the matrix method. Using this method, a formulation is here presented for the complete nonlinear programming problem which, for a given configuration, can ensure the globally minimum vapor duty of the configuration. Furthermore, a set of nonlinear equations designed to represent the capital and operating costs of the system are described. The need for a global optimization algorithm in the formulation of the cost product is demonstrated by comparison with a two-stage search algorithm; in addition, the cost formulation is compared to that of the vapor duty

  10. Multicomponent recycled plastics: considerations about their use in food contact applications.

    PubMed

    Nerín, C; Salafranca, J; Rubio, C; Cacho, J

    1998-10-01

    Two multicomponent post-use recycled plastics named as NPP40A3 (formulated with 85% HDPE and 15% of a PP-PS-PVC mixture) and NPP40A6 (formulated with 80% NPP40A3, 10% ABS and 10% HIPS), both of them with 3.1% of plasticizer and 0.6% of stabilizer to obtain a better final product, have been analysed. Plastics were extracted both with dichloromethane and methylbenzene, and analysed by HPLC and GC-MS to identify the maximum possible number of compounds. Major additives quantified were di(ethylhexyl)phthalate (3.262% and 2.955% respectively) and Irganox 1010 (0.473% and 0.498% respectively). Several degradation compounds have been detected. In order to check if these plastics could be used in food contact applications, global and specific migration tests have been applied. The results obtained are discussed.

  11. Global optimization of multicomponent distillation configurations: 2. Enumeration based global minimization algorithm

    DOE PAGES

    Nallasivam, Ulaganathan; Shah, Vishesh H.; Shenvi, Anirudh A.; ...

    2016-02-10

    We present a general Global Minimization Algorithm (GMA) to identify basic or thermally coupled distillation configurations that require the least vapor duty under minimum reflux conditions for separating any ideal or near-ideal multicomponent mixture into a desired number of product streams. In this algorithm, global optimality is guaranteed by modeling the system using Underwood equations and reformulating the resulting constraints to bilinear inequalities. The speed of convergence to the globally optimal solution is increased by using appropriate feasibility and optimality based variable-range reduction techniques and by developing valid inequalities. As a result, the GMA can be coupled with already developedmore » techniques that enumerate basic and thermally coupled distillation configurations, to provide for the first time, a global optimization based rank-list of distillation configurations.« less

  12. Global optimization of multicomponent distillation configurations: 2. Enumeration based global minimization algorithm

    SciTech Connect

    Nallasivam, Ulaganathan; Shah, Vishesh H.; Shenvi, Anirudh A.; Huff, Joshua; Tawarmalani, Mohit; Agrawal, Rakesh

    2016-02-10

    We present a general Global Minimization Algorithm (GMA) to identify basic or thermally coupled distillation configurations that require the least vapor duty under minimum reflux conditions for separating any ideal or near-ideal multicomponent mixture into a desired number of product streams. In this algorithm, global optimality is guaranteed by modeling the system using Underwood equations and reformulating the resulting constraints to bilinear inequalities. The speed of convergence to the globally optimal solution is increased by using appropriate feasibility and optimality based variable-range reduction techniques and by developing valid inequalities. As a result, the GMA can be coupled with already developed techniques that enumerate basic and thermally coupled distillation configurations, to provide for the first time, a global optimization based rank-list of distillation configurations.

  13. Size matters in the water uptake and hygroscopic growth of atmospherically relevant multicomponent aerosol particles.

    PubMed

    Laskina, Olga; Morris, Holly S; Grandquist, Joshua R; Qin, Zhen; Stone, Elizabeth A; Tivanski, Alexei V; Grassian, Vicki H

    2015-05-14

    Understanding the interactions of water with atmospheric aerosols is crucial for determining the size, physical state, reactivity, and climate impacts of this important component of the Earth's atmosphere. Here we show that water uptake and hygroscopic growth of multicomponent, atmospherically relevant particles can be size dependent when comparing 100 nm versus ca. 6 μm sized particles. It was determined that particles composed of ammonium sulfate with succinic acid and of a mixture of chlorides typical of the marine environment show size-dependent hygroscopic behavior. Microscopic analysis of the distribution of components within the aerosol particles show that the size dependence is due to differences in the mixing state, that is, whether particles are homogeneously mixed or phase separated, for different sized particles. This morphology-dependent hygroscopicity has consequences for heterogeneous atmospheric chemistry as well as aerosol interactions with electromagnetic radiation and clouds.

  14. Usage of air jigging for multi-component separation of construction and demolition waste.

    PubMed

    Ambrós, Weslei Monteiro; Sampaio, Carlos Hoffmann; Cazacliu, Bogdan Grigore; Miltzarek, Gerson Luis; Miranda, Leonardo R

    2017-02-01

    The use of air jigging for performing multi-component separation in the treatment of mixed construction and demolition waste was studied. Sorting tests were carried out with mixtures of equal bulk volume of concrete and brick in which fixed quantities of unwanted materials - gypsum, wood and paper - were added. Experimental results have demonstrated the possibility to use air jigging to carry out both the removal of low-density contaminants and the concrete concentration in only one process step. In relation to the removal of contaminants only, the overall performance of jigging process can be comparable with that of commercial air classifiers and automatic sorting systems. Also, the initial content of contaminants seems does not have a significant effect on the separation extent. These results are of particular importance for recycling plants processing as they represent an alternative to optimize the use of air jigs. Further investigation is needed in order to evaluate the practical feasibility of such method.

  15. Signal processing with a summing operational amplifier in multicomponent potentiometric titrations.

    PubMed

    Parczewski, A

    1987-06-01

    It has been proved that application of two indicator electrodes connected to the ordinary titration apparatus through an auxiliary electronic device (a summing operational amplifier) significantly extends the scope of multicomponent potentiometric titrations in which the analytes are determined simultaneously from a single titration curve. For each analyte there is a corresponding potential jump on the titration curve. By application of the proposed auxiliary device, the sum of the electrode potentials is measured. The device also enables the relative sizes of the potential jumps at the end-points on the titration curve to be varied. The advantages of the proposed signal processing are exemplified by complexometric potentiometric titrations of Fe(III) and Cu(II) in mixtures, with a platinum electrode and a copper ion-selective electrode as the indicator electrodes.

  16. Mineral Selection for Multicomponent Equilibrium Geothermometry

    DOE PAGES

    Plamer, C. D.; Ohly, S. R.; Smith, R. W.; ...

    2015-04-01

    Multicomponent geothermometry requires knowledge of the mineral phases in the reservoir with which the geothermal fluids may be equilibrated. These minerals phases are most often alteration products rather than primary minerals. We have reviewed the literature on geothermal systems representing most major geologic environments typically associated with geothermal activity and identified potential alteration products in various environments. We have included this information in RTEst, a code we have developed to estimate reservoir conditions (temperature, CO2 fugacity) from the geochemistry of near-surface geothermal waters. The information has been included in RTEst through the addition of filters that decrease the potential numbermore » of minerals from all possibilities based on the basis species to those that are more relevant to the particular conditions in which the user is interested. The three groups of filters include host rock type (tholeiitic, calc-alkaline, silicic, siliciclastic, carbonate), water type (acidic, neutral), and the temperature range over which the alteration minerals were formed (low, medium, high). The user-chosen mineral assemblage is checked to make sure that it does not violate the Gibbs phase rule. The user can select one of three mineral saturation weighting schemes that decrease the chance the optimization from being skewed by reaction stoichiometry or analytical uncertainty.« less

  17. Mineral Selection for Multicomponent Equilibrium Geothermometry

    SciTech Connect

    Plamer, C. D.; Ohly, S. R.; Smith, R. W.; Neupane, G.; McLing, T.; Mattson, E.

    2015-04-01

    Multicomponent geothermometry requires knowledge of the mineral phases in the reservoir with which the geothermal fluids may be equilibrated. These minerals phases are most often alteration products rather than primary minerals. We have reviewed the literature on geothermal systems representing most major geologic environments typically associated with geothermal activity and identified potential alteration products in various environments. We have included this information in RTEst, a code we have developed to estimate reservoir conditions (temperature, CO2 fugacity) from the geochemistry of near-surface geothermal waters. The information has been included in RTEst through the addition of filters that decrease the potential number of minerals from all possibilities based on the basis species to those that are more relevant to the particular conditions in which the user is interested. The three groups of filters include host rock type (tholeiitic, calc-alkaline, silicic, siliciclastic, carbonate), water type (acidic, neutral), and the temperature range over which the alteration minerals were formed (low, medium, high). The user-chosen mineral assemblage is checked to make sure that it does not violate the Gibbs phase rule. The user can select one of three mineral saturation weighting schemes that decrease the chance the optimization from being skewed by reaction stoichiometry or analytical uncertainty.

  18. An evaporation model of multicomponent solution drops

    NASA Astrophysics Data System (ADS)

    Sartori, Silvana; Liñán, Amable; Lasheras, Juan C.

    2010-11-01

    Solutions of polymers are widely used in the pharmaceutical industry as tablets coatings. These allow controlling the rate at which the drug is delivered, taste or appearance. The coating is performed by spraying and drying the tablets at moderate temperatures. The wetting of the coating solution on the pill's surface depends on the droplet Webber and Re numbers, angle of impact and on the rheological properties of the droplet. We present a model for the evaporation of multicomponent solutions droplets in a hot air environment with temperatures substantially lower than the boiling temperature of the solvent. As the liquid vaporizes from the surface the fluid in the drop increases in concentration, until reaching its saturation point. After saturation, precipitation occurs uniformly within the drop. As the surface regresses, a compacting front formed by the precipitate at its maximum packing density advances into the drop, while the solute continues precipitating uniformly. This porous shell grows fast due to the double effect of surface regression and precipitation. The evaporation rate is determined by the rates at which heat is transported to the droplet surface and at which liquid vapor diffuses away from it. When the drop is fully compacted, the evaporation is drastically reduced.

  19. Spontaneous Ignition Characteristics of Hydrocarbon Fuel-air Mixtures

    NASA Technical Reports Server (NTRS)

    Lefebvre, A. H.; Freeman, G. W.

    1983-01-01

    Although the subject of spontaneous ignition of liquid fuels has received considerable attention in the past, the role of fuel evaporation in the overall spontaneous ignition process is still unclear. A main purpose of this research is to carry out measurements of ignition delay times, using fuels of current and anticipated future aeronautical interest, at test conditions that are representative of those encountered in modern gas turbine engines. Attention is focused on the fuel injection process, in particlar the measurement and control of man fuel drop size and fuel-air spatial distribution. The experiments are designed to provide accurate information on the role of fuel evaporation processes in determining the overall ignition delay time. The second objective is to examine in detail the theoretical aspects of spontaneous ignition in order to improve upon current knowledge and understanding of the basic processes involved, so that the results of the investigation can find general and widespead application.

  20. Composition and Temperature Dependence of Shear Viscosity of Hydrocarbon Mixtures

    DTIC Science & Technology

    1980-07-01

    model for viscosity of liquids , we feel that this is a very good correlation between molecular structure and viscosity, and it appears then that the...B. Thole, "The Viscosity of Liquids ," Longmans, Green and Co., London (1914). 15. W. R. Gambill, Chem. Eng, 66, 151 (1959) 16. P. K. Katti and M. M

  1. Gaseous hydrocarbon-air detonations

    SciTech Connect

    Tieszen, S.R.; Stamps, D.W. ); Westbrook, C.K.; Pitz, W.J. )

    1991-04-01

    Detonation cell width measurements were made on mixtures of air and methane, ethane, dimethyl-ether, nitroethane, ethylene, acetylene, propane, 1,2-epoxypropane, n-hexane, 1-nitrohexane, mixed primary hexylnitrate, n-octane, 2,2,4-trimethylpentane, cyclooctane, 1-octene, cis-cyclooctene, 1,7-octadiene, 1-octyne, n-decane, 1,2-epoxydecane, pentyl-ether, and JP4. Cell width measurements were carried out at 25 and 100 {degrees} C for some of these fuel-air mixtures. For the stoichiometric alkanes, alkenes, and alkynes, there is a very slight decrease in the detonation cell width with increasing initial temperature from 25 {degrees} C to 100 {degrees} C, although the differences are within the experimentally uncertainties in cell width measurements. Also within the uncertainty limits of the measurements, there is no variation in detonation cell width with increase fuel molecular weight for n-alkanes from ethane to n-decane. Molecular structure is found to affect detonability for C{sub 8} hydrocarbons, where the saturated ring structure is more sensitive than the straight-chain alkane, which is more sensitive than the branched-chain alkane. Unsaturated alkenes and alkynes are more sensitive to detonation than saturated alkanes.

  2. Gaseous hydrocarbon-air detonations

    SciTech Connect

    Tieszen, S.R.; Stamps, D.W.; Westbrook, C.K.; Pitz, W.J.

    1988-01-01

    Detonation cell width measurements are made on mixtures of air and methane, ethane, dimethyl-ether, nitroethane, ethylene, acetylene, propane, 1,2-epoxypropane, n-hexane, 1-nitrohexane, mixed primary hexylnitrate, n-octane, 2,2,4-trimethylpentane, cyclooctane, 1-octene, cis-cyclooctene, 1-7-octadiene, 1-octyne, n-decane, 1,2-epoxydecane, pentyl-ether, and JP4. There is a slight decrease in detonation cell width that is within the uncertainty of the data for stoichiometric alkanes, alkenes, and alkynes with increasing temperature between 25 and 100/degree/C. Also there appears to be no effect of molecular weight from ethane to decane, on detonation cell width for stoichiometric alkanes. Molecular structure is found to affect detonability for C/sub 8/ hydrocarbons, where the saturated ring structure is more sensitive than the straight-chain alkane. Unsaturated alkenes and alkynes are more sensitive to detonation than saturated alkanes. However, the degree of sensitization decreases with increasing molecular weight. Addition of functional groups such as nitro, nitrate, epoxy, and ethers are found to significantly reduce the detonation cell width from the parent n-alkane. Nitrated n-alkanes can be more sensitive than hydrogen-air mixtures. The increase in sensitivity of epoxy groups appears to be related to the oxygen to carbon ratio of the molecule. Good results are obtained between the data and predictions from a ZND model with detailed chemical kinetics. 46 refs., 8 figs., 4 tabs.

  3. Nonequilibrium multiphase mixture modeling of energetic material response

    SciTech Connect

    Baer, M.R.; Hertel, E.; Bell, R.

    1995-12-31

    To model the shock-induced behavior of porous or damaged energetic materials, a nonequilibrium mixture theory has been developed and incorporated into the shock physics code, CTH. Foundation for this multiphase model is based on a continuum mixture formulation given by Baer and Nunziato. In this nonequilibrium approach, multiple thermodynamic and mechanics fields are resolved including the effects of material relative motion, rate-dependent compaction, drag and heat transfer interphase effects and multiple-step combustion. Benchmark calculations are presented which simulate low-velocity piston impact on a propellant porous bed and experimentally-measured wave features are well replicated with this model. This mixture model introduces micromechanical models for the initiation and growth of reactive multicomponent flow which are key features to describe shock initiation and self-accelerated deflagration-to-detonation combustion behavior. To complement one-dimensional simulation, two dimensional numerical simulations are presented which indicate wave curvature effects due to the loss of wall confinement.

  4. Nuclear fusion reaction rates for strongly coupled ionic mixtures

    SciTech Connect

    Chugunov, A. I.; DeWitt, H. E.

    2009-07-15

    We analyze the effect of plasma screening on nuclear reaction rates in dense matter composed of atomic nuclei of one or two types. We perform semiclassical calculations of the Coulomb barrier penetrability taking into account a radial mean-field potential of plasma ions. The mean-field potential is extracted from the results of extensive Monte Carlo calculations of radial pair distribution functions of ions in binary ionic mixtures. We calculate the reaction rates in a wide range of plasma parameters and approximate these rates by an analytical expression that is expected to be applicable to multicomponent ion mixtures. Also, we analyze Gamow-peak energies of reacting ions in various nuclear burning regimes. For illustration, we study nuclear burning in {sup 12}C-{sup 16}O mixtures.

  5. Photocatalytic oxidation of chlorophenols in single-component and multicomponent systems

    SciTech Connect

    Puma, G.L.; Yue, P.L.

    1999-09-01

    The photocatalytic oxidation of single-component and multicomponent systems consisting of chlorophenols in aqueous TiO{sub 2} suspension was investigated using long, medium, and short wavelength UV radiation. In the single-component experiments, 2-chlorophenol (2-CP), 2,4-dichlorophenol, 2,4,6-trichlorophenol, pentachlorophenol, and 4-chloro-3-methylphenol (4-Cl-3-MP) were found to degrade at the same rate. The rate of mineralization of 4-Cl-3-MP was higher than that of the others. Power law kinetic models for the temporal prediction of the degradation and mineralization profiles fitted the experimental results well for the single-component systems. The application of these models to represent the simultaneous oxidation of a binary mixture of 2-CP and 4-Cl-3-MP was examined for several equimolar and nonequimolar mixtures. Competitive inhibition kinetics were observed. Under equimolar feed conditions the rates of degradation of the total mixture were comparable to those for single-component systems and could be represented well by the model developed for single-component systems. When one of the two substrates was in excess, the overall oxidation kinetics were controlled by that substrate and the system could therefore be treated as a single-component system.

  6. Hygroscopicity of internally mixed multi-component aerosol particles of atmospheric relevance

    NASA Astrophysics Data System (ADS)

    Liu, Qifan; Jing, Bo; Peng, Chao; Tong, Shengrui; Wang, Weigang; Ge, Maofa

    2016-01-01

    The hygroscopic properties of two water-soluble organic compounds (WSOCs) relevant to urban haze pollution (phthalic acid and levoglucosan) and their internally mixtures with inorganic salts (ammonium sulfate and ammonium nitrate) are investigated using a hygroscopicity tandem differential mobility analyzer (H-TDMA) system. The multi-component particles uptake water gradually in the range 5-90% relative humidity (RH). The experimental results are compared with the thermodynamic model predictions. For most mixtures, Extended Aerosol Inorganic Model (E-AIM) predictions agree well with the measured growth factors. The hygroscopic growth of mixed particles can be well described by the Zdanovskii-Stokes-Robinson (ZSR) relation as long as the mixed particles are completely liquid. ZSR calculations underestimate the water uptake of mixed particles at moderate RH due to the partial dissolution of ammonium sulfate in the organic and ammonium nitrate solution in this RH region. The phase of ammonium nitrate in the initial dry particles changes dramatically with the composition of mixtures. The presence of organics in the mixed particles can inhibit the crystallization of ammonium nitrate during the drying process and results in water uptake at low RH (RH < 60%). These results demonstrate that certain representative WSOCs can substantially influence the hygroscopicity of inorganic salts and overall water uptake of particles.

  7. HETEROGENEOUS PHOTOCATALYTIC DECOMPOSITION OF POLY- AROMATIC HYDROCARBONS OVER TITANIUM DIOXIDE

    EPA Science Inventory

    The photocatalytic degradation of a mixture of 16 polyaromatic hydrocarbons (PAHs) was investigated in aqueous suspensions of high surface area TiO2 illuminated with 310–380 nm ultraviolet light. Triethylamine was utilized for extraction of PAH compounds from motor oil...

  8. Plasma Processing Of Hydrocarbon

    SciTech Connect

    Grandy, Jon D; Peter C. Kong; Brent A. Detering; Larry D. Zuck

    2007-05-01

    The Idaho National Laboratory (INL) developed several patented plasma technologies for hydrocarbon processing. The INL patents include nonthermal and thermal plasma technologies for direct natural gas to liquid conversion, upgrading low value heavy oil to synthetic light crude, and to convert refinery bottom heavy streams directly to transportation fuel products. Proof of concepts has been demonstrated with bench scale plasma processes and systems to convert heavy and light hydrocarbons to higher market value products. This paper provides an overview of three selected INL patented plasma technologies for hydrocarbon conversion or upgrade.

  9. Volatile hydrocarbons and fuel oxygenates: Chapter 12

    USGS Publications Warehouse

    Cozzarelli, Isabelle M.

    2014-01-01

    Petroleum hydrocarbons and fuel oxygenates are among the most commonly occurring and widely distributed contaminants in the environment. This chapter presents a summary of the sources, transport, fate, and remediation of volatile fuel hydrocarbons and fuel additives in the environment. Much research has focused on the transport and transformation processes of petroleum hydrocarbons and fuel oxygenates, such as benzene, toluene, ethylbenzene, and xylenes and methyl tert‐butyl ether, in groundwater following release from underground storage tanks. Natural attenuation from biodegradation limits the movement of these contaminants and has received considerable attention as an environmental restoration option. This chapter summarizes approaches to environmental restoration, including those that rely on natural attenuation, and also engineered or enhanced remediation. Researchers are increasingly combining several microbial and molecular-based methods to give a complete picture of biodegradation potential and occurrence at contaminated field sites. New insights into the fate of petroleum hydrocarbons and fuel additives have been gained by recent advances in analytical tools and approaches, including stable isotope fractionation, analysis of metabolic intermediates, and direct microbial evidence. However, development of long-term detailed monitoring programs is required to further develop conceptual models of natural attenuation and increase our understanding of the behavior of contaminant mixtures in the subsurface.

  10. Analysis of the repeatability of time-lapse 3d vsp multicomponent surveys, delhi field

    NASA Astrophysics Data System (ADS)

    Carvalho, Mariana Fernandes de

    Delhi Field is a producing oil field located in northeastern Louisiana. In order to monitor the CO2 sweep efficiency, time-lapse 3D seismic data have been acquired in this area. Time-lapse studies are increasingly used to evaluate changes in the seismic response induced by the production of hydrocarbons or the injection of water, CO2 or steam into a reservoir. A 4D seismic signal is generated by a combination of production and injection effects within the reservoir as well as non-repeatability effects. In order to get reliable results from time-lapse seismic methods, it is important to distinguish the production and injection effects from the non-repeatability effects in the 4D seismic signal. Repeatability of 4D land seismic data is affected by several factors. The most significant of them are: source and receiver geometry inaccuracies, differences in seismic sources signatures, variations in the immediate near surface and ambient non-repeatable noise. In this project, two 3D multicomponent VSP surveys acquired in Delhi Field were used to quantify the relative contribution of each factor that can affect the repeatability in land seismic data. The factors analyzed in this study were: source and receiver geometry inaccura- cies, variations in the immediate near surface and ambient non-repeatable noise. This study showed that all these factors had a significant impact on the repeatability of the successive multicomponent VSP surveys in Delhi Field. This project also shows the advantages and disadvantages in the use of different repeata- bility metrics, normalized-root-mean-square (NRMS) difference and signal-to-distortion ratio (SDR) attribute, to evaluate the level of seismic repeatability between successive time-lapse seismic surveys. It is observed that NRMS difference is greatly influenced by time-shifts and that SDR attribute combined with the time-shift may give more distinct and representative repeatability information than the NRMS difference.

  11. A review on multicomponent seismology: A potential seismic application for reservoir characterization.

    PubMed

    Farfour, Mohammed; Yoon, Wang Jung

    2016-05-01

    Searching for hydrocarbon reserves in deep subsurface is the main concern of wide community of geophysicists and geoscientists in petroleum industry. Exploration seismology has substantially contributed to finding and developing giant fields worldwide. The technology has evolved from two to three-dimensional method, and later added a fourth dimension for reservoir monitoring. Continuous depletion of many old fields and the increasing world consumption of crude oil pushed to consistently search for techniques that help recover more reserves from old fields and find alternative fields in more complex and deeper formations either on land and in offshore. In such environments, conventional seismic with the compressional (P) wave alone proved to be insufficient. Multicomponent seismology came as a solution to most limitations encountered in P-wave imaging. That is, recording different components of the seismic wave field allowed geophysicists to map complex reservoirs and extract information that could not be extracted previously. The technology demonstrated its value in many fields and gained popularity in basins worldwide. In this review study, we give an overview about multicomponent seismology, its history, data acquisition, processing and interpretation as well as the state-of the-art of its applications. Recent examples from world basins are highlighted. The study concludes that despite the success achieved in many geographical areas such as deep offshore in the Gulf of Mexico, Western Canada Sedimentary Basin (WCSB), North Sea, Offshore Brazil, China and Australia, much work remains for the technology to gain similar acceptance in other areas such as Middle East, East Asia, West Africa and North Africa. However, with the tremendous advances reported in data recording, processing and interpretation, the situation may change.

  12. A review on multicomponent seismology: A potential seismic application for reservoir characterization

    PubMed Central

    Farfour, Mohammed; Yoon, Wang Jung

    2015-01-01

    Searching for hydrocarbon reserves in deep subsurface is the main concern of wide community of geophysicists and geoscientists in petroleum industry. Exploration seismology has substantially contributed to finding and developing giant fields worldwide. The technology has evolved from two to three-dimensional method, and later added a fourth dimension for reservoir monitoring. Continuous depletion of many old fields and the increasing world consumption of crude oil pushed to consistently search for techniques that help recover more reserves from old fields and find alternative fields in more complex and deeper formations either on land and in offshore. In such environments, conventional seismic with the compressional (P) wave alone proved to be insufficient. Multicomponent seismology came as a solution to most limitations encountered in P-wave imaging. That is, recording different components of the seismic wave field allowed geophysicists to map complex reservoirs and extract information that could not be extracted previously. The technology demonstrated its value in many fields and gained popularity in basins worldwide. In this review study, we give an overview about multicomponent seismology, its history, data acquisition, processing and interpretation as well as the state-of the-art of its applications. Recent examples from world basins are highlighted. The study concludes that despite the success achieved in many geographical areas such as deep offshore in the Gulf of Mexico, Western Canada Sedimentary Basin (WCSB), North Sea, Offshore Brazil, China and Australia, much work remains for the technology to gain similar acceptance in other areas such as Middle East, East Asia, West Africa and North Africa. However, with the tremendous advances reported in data recording, processing and interpretation, the situation may change. PMID:27222756

  13. Multicomponent seismic noise attenuation with multivariate order statistic filters

    NASA Astrophysics Data System (ADS)

    Wang, Chao; Wang, Yun; Wang, Xiaokai; Xun, Chao

    2016-10-01

    The vector relationship between multicomponent seismic data is highly important for multicomponent processing and interpretation, but this vector relationship could be damaged when each component is processed individually. To overcome the drawback of standard component-by-component filtering, multivariate order statistic filters are introduced and extended to attenuate the noise of multicomponent seismic data by treating such dataset as a vector wavefield rather than a set of scalar fields. According to the characteristics of seismic signals, we implement this type of multivariate filtering along local events. First, the optimal local events are recognized according to the similarity between the vector signals which are windowed from neighbouring seismic traces with a sliding time window along each trial trajectory. An efficient strategy is used to reduce the computational cost of similarity measurement for vector signals. Next, one vector sample each from the neighbouring traces are extracted along the optimal local event as the input data for a multivariate filter. Different multivariate filters are optimal for different noise. The multichannel modified trimmed mean (MTM) filter, as one of the multivariate order statistic filters, is applied to synthetic and field multicomponent seismic data to test its performance for attenuating white Gaussian noise. The results indicate that the multichannel MTM filter can attenuate noise while preserving the relative amplitude information of multicomponent seismic data more effectively than a single-channel filter.

  14. Approximate Equations for Transport Coefficients of Multicomponent Mixtures of Neutral Gases.

    DTIC Science & Technology

    1980-11-19

    Journal of Chemical Physics, 25, 360 (1956). 51. H. Gruss and H. Schmick, Wiss. Veroffentlich Siemens -Konzern, 7, 202 (1928). 52. Clingman, Brokaw, and...component i in quantum state ai , given by ia nx in (D.4) with V - i" (D.5) i-i a We have left the index i off a in all equations for brevity. Notice

  15. Fast, broadband, rugged spectrometer for near-infrared measurements of organic solutions and multicomponent mixtures.

    PubMed

    Claps, Ricardo; Virojanapa, Jeffrey

    2013-11-01

    The mode of operation and theoretical concept behind a type of near-infrared spectrometer is discussed, which is used to measure concentrations of glucose, ethanol, CaCl2, and KCl solutions in water, respectively. The main features of the instrument are its potential for short time-to-measurement resolution on the order of tens of milliseconds, its broad spectral bandwidth from 1.0 to 2.4 μm, and its ruggedness. These features allow the device to operate remotely in field applications and to utilize a wide variety of optical interfaces based on state-of-the-art fiber optic technology. Also, they provide a straightforward path to miniaturization with the concomitant enhancement in time resolution and applicability of the instrument and the technique.

  16. Thin-layer chromatography and colorimetric analysis of multi-component explosive mixtures

    SciTech Connect

    Pagoria, Philip F.; Mitchell, Alexander R.; Whipple, Richard E.; Carman, M. Leslie

    2014-08-26

    A thin-layer chromatography method for detection and identification of common military and peroxide explosives in samples includes the steps of provide a reverse-phase thin-layer chromatography plate; prepare the plate by marking spots on which to deposit the samples by touching the plate with a marker; spot one micro liter of a first standard onto one of the spots, spot one micro liter of a second standard onto another of the spots, and spot samples onto other of spots producing a spotted plate; add eluent to a developing chamber; add the spotted plate to the developing chamber; remove the spotted plate from the developing chamber producing a developed plate; place the developed plate in an ultraviolet light box; add a visualization agent to a dip tank; dip the developed plate in the dip tank and remove the developed plate quickly; and detect explosives by viewing said developed plate.

  17. Multicomponent solubility parameters for single-walled carbon nanotube-solvent mixtures.

    PubMed

    Bergin, Shane D; Sun, Zhenyu; Rickard, David; Streich, Philip V; Hamilton, James P; Coleman, Jonathan N

    2009-08-25

    We have measured the dispersibility of single-walled carbon nanotubes in a range of solvents, observing values as high as 3.5 mg/mL. By plotting the nanotube dispersibility as a function of the Hansen solubility parameters of the solvents, we have confirmed that successful solvents occupy a well-defined range of Hansen parameter space. The level of dispersibility is more sensitive to the dispersive Hansen parameter than the polar or H-bonding Hansen parameter. We estimate the dispersion, polar, and hydrogen bonding Hansen parameter for the nanotubes to be = 17.8 MPa(1/2), = 7.5 MPa(1/2), and = 7.6 MPa(1/2). We find that the nanotube dispersibility in good solvents decays smoothly with the distance in Hansen space from solvent to nanotube solubility parameters. Finally, we propose that neither Hildebrand nor Hansen solubility parameters are fundamental quantities when it comes to nanotube-solvent interactions. We show that the previously calculated dependence of nanotube Hildebrand parameter on nanotube diameter can be reproduced by deriving a simple expression based on the nanotube surface energy. We show that solubility parameters based on surface energy give equivalent results to Hansen solubility parameters. However, we note that, contrary to solubility theory, a number of nonsolvents for nanotubes have both Hansen and surface energy solubility parameters similar to those calculated for nanotubes. The nature of the distinction between solvents and nonsolvents remains to be fully understood.

  18. Process for converting light alkanes to higher hydrocarbons

    DOEpatents

    Noceti, Richard P.; Taylor, Charles E.

    1988-01-01

    A process is disclosed for the production of aromatic-rich, gasoline boiling range hydrocarbons from the lower alkanes, particularly from methane. The process is carried out in two stages. In the first, alkane is reacted with oxygen and hydrogen chloride over an oxyhydrochlorination catalyst such as copper chloride with minor proportions of potassium chloride and rare earth chloride. This produces an intermediate gaseous mixture containing water and chlorinated alkanes. The chlorinated alkanes are contacted with a crystalline aluminosilicate catalyst in the hydrogen or metal promoted form to produce gasoline range hydrocarbons with a high proportion of aromatics and a small percentage of light hydrocarbons (C.sub.2 -C.sub.4). The light hydrocarbons can be recycled for further processing over the oxyhydrochlorination catalyst.

  19. Conversion of Pentose-Derived Furans into Hydrocarbon Fuels

    SciTech Connect

    Moens, L.; Johnson, D. K.

    2012-01-01

    We are interested in the conversion of biomass-derived hemicellulose into hydrocarbon molecules that can be used in the formulation of 'drop-in' fuels such as gasoline (C5-12), diesel (C10-20) and jet fuel (C9-16). Our focus lies on the use of furfuryl alcohol as a starting material since that is already produced commercially from hemicellulose-derived pentoses. The steps required to convert the latter into hydrocarbons are 1) oligomerization of furfuryl alcohol to form dimers (C10) and trimers (C15), and 2) hydrotreatment of the dimers and trimers to produce a mixture of linear hydrocarbons with carbon chain lengths in the range of diesel and jet fuels. However, furfuryl alcohol readily polymerizes to form resins in the presence of an acid catalyst, and the exothermic oligomerization must be carried out under reaction control. This presentation will discuss our progress in the development of this sugar-to-hydrocarbon pathway.

  20. Multicomponent Protein Cage Architectures for Photocatalysis

    SciTech Connect

    Gupta, Arunava; Prevelige, Peter E

    2016-01-04

    The primary goal of the project was to develop protein-templated approaches for the synthesis and directed assembly of semiconductor nanomaterials that are efficient for visible light absorption and hydrogen production. In general, visible-light-driven photocatalysis reactions exhibit low quantum efficiency for solar energy conversion primarily because of materials-related issues and limitations, such as the control of the band gap, band structure, photochemical stability, and available reactive surface area of the photocatalyst. Synthesis of multicomponent hierarchical nano-architectures, consisting of semiconductor nanoparticles (NPs) with desired optical properties fabricated to maximize spatial proximity for optimum electron and energy transfer represents an attractive route for addressing the problem. Virus capsids are highly symmetrical, self-assembling protein cage nanoparticles that exist in a range of sizes and symmetries. Selective deposition of inorganic, by design, at specific locations on virus capsids affords precise control over the size, spacing, and assembly of nanomaterials, resulting in uniform and reproducible nano-architectures. We utilized the self-assembling capabilities of the 420 subunit, 60 nm icosahedral, P22 virus capsid to direct the nucleation, growth, and proximity of a range of component materials. Controlled fabrication on the exterior of the temperature stable shell was achieved by genetically encoding specific binding peptides into an externally exposed loop which is displayed on each of the 420 coat protein subunits. Localization of complimentary materials to the interior of the particle was achieved through the use “scaffolding-fusion proteins. The scaffolding domain drives coat protein polymerization resulting in a coat protein shell surrounding a core of approximately 300 scaffolding/fusion molecules. The fusion domain comprises a peptide which specifically binds the semiconductor material of interest.

  1. Cyclic Peptidomimetics and Pseudopeptides from Multicomponent Reactions

    NASA Astrophysics Data System (ADS)

    Wessjohann, Ludger A.; Rhoden, Cristiano R. B.; Rivera, Daniel G.; Vercillo, Otilie Eichler

    Multicomponent reactions (MCRs) that provide in the final product amides are suitable to produce peptides and peptide-like moieties. The Passerini and Staudinger reactions provide one amide bond, and the Ugi-four-component reaction generates two amides from three or even four (or more) components, respectively. The Ugi-reaction thus is most important to produce peptides and peptoids while the Passerini reaction is useful to generate depsipeptoid moieties. In order to produce cyclic peptides and pseudopeptides, the linear peptidic MCR products have to be cyclized, usually with the help of bifunctional or activatable building blocks. Orthogonal but cyclizable secondary functionalities that need no protection in isonitrile MCRs commonly include alkenes (for ring closing metathesis), azide/alkyne (for Huisgen click reactions) or dienes and enoates (Diels-Alder) etc. If MCR-reactive groups are to be used also for the cyclisation, monoprotected bifunctional building blocks are used and deprotected after the MCR, e.g. for Ugi reactions as Ugi-Deprotection-Cyclisation (UDC). Alternatively one of the former building blocks or functional groups generated by the MCR can be activated. Most commonly these are activated amides (from so-called convertible isonitriles) which can be used e.g. for Ugi-Activation-Cyclisation (UAC) protocols, or most recently for a simultaneous use of both strategies Ugi-Deprotection/Activation-Cyclisation (UDAC). These methods mostly lead to small, medicinally relevant peptide turn mimics. In an opposing strategy, the MCR is rather used as ring-closing reaction, thereby introducing a (di-)peptide moiety. Most recently these processes have been combined to use MCRs for both, linear precursor synthesis and cyclisation. These multiple MCR approaches allow the most efficient and versatile one pot synthesis of macrocyclic pseudopeptides known to date.

  2. Process for preparing hydrocarbons

    SciTech Connect

    Breuker, J.H.; De H.H.; Kwant, P.B.

    1980-01-15

    A process for preparing light distillate fractions and medicinal oil from heavy hydrocarbon oils comprises two-stage hydrocracking, fractionation distillation and catalytic hydrotreatment of at least part of the fractionation residue.

  3. Liquid-liquid equilibria for ternary polymer mixtures

    NASA Astrophysics Data System (ADS)

    Oh, Suk Yung; Bae, Young Chan

    2011-01-01

    A molecular thermodynamic model for multicomponent systems based on a closed-packed lattice model is presented based on two contributions; entropy and energy contribution. The calculated liquid-liquid equilibria of ternary chainlike mixtures agreed with Monte Carlo simulation results. The proposed model can satisfactorily predict Types 0, 1, 2 and 3 phase separations of the Treybal classification. The model parameters obtained from the binary systems were used to directly predict real ternary systems and the calculated results correlated well with experimental data using few adjustable parameters. Specific interactions in associated binary systems were considered using a secondary lattice.

  4. Quantitative time-of-flight secondary ion mass spectrometry for the characterization of multicomponent adsorbed protein films

    NASA Astrophysics Data System (ADS)

    Wagner, M. S.; Shen, M.; Horbett, T. A.; Castner, David G.

    2003-01-01

    Time-of-flight secondary ion mass spectrometry (ToF-SIMS) is ideal for the characterization of adsorbed proteins due to its chemical specificity and surface sensitivity. We have employed ToF-SIMS and multivariate analysis to determine the surface composition of adsorbed protein films from binary mixtures, blood serum, and blood plasma. Good correlation between ToF-SIMS data and independent radiolabeling studies was achieved for binary mixtures, though these results depended on the substrate. Qualitative insight into the composition of the serum and plasma protein films was obtained via comparison to standard single protein film spectra. ToF-SIMS and multivariate analysis were able to measure the surface composition of multicomponent adsorbed protein films.

  5. Coal liquefaction process using pretreatment with a binary solvent mixture

    DOEpatents

    Miller, Robert N.

    1986-01-01

    An improved process for thermal solvent refining or hydroliquefaction of non-anthracitic coal at elevated temperatures under hydrogen pressure in a hydrogen donor solvent comprises pretreating the coal with a binary mixture of an aromatic hydrocarbon and an aliphatic alcohol at a temperature below 300.degree. C. before the hydroliquefaction step. This treatment generally increases both conversion of coal and yields of oil.

  6. Biodegradation of aliphatic hydrocarbons in the presence of hydroxy cucurbit[6]uril.

    PubMed

    Pasumarthi, Rajesh; Kumar, Vikash; Chandrasekharan, Sivaraman; Ganguly, Anasuya; Banerjee, Mainak; Mutnuri, Srikanth

    2014-11-15

    Aliphatic hydrocarbons are one of the major environmental pollutants with reduced bioavailability. The present study focuses on the effect of hydroxy cucurbit[6]uril on the bioavailability of hydrocarbons. A bacterial consortium was used for biodegradation studies under saline and non-saline conditions. Based on denaturing gradient gel electrophoresis results it was found that the consortium under saline conditions had two different strains. The experiment was conducted in microcosms with tetradecane, hexadecane, octadecane and mixture of the mentioned hydrocarbons as the sole carbon source. The residual hydrocarbon was quantified using gas chromatography every 24h. It was found that biodegradation of tetradecane and hexadecane, as individual carbon source increased in the presence of hydroxy CB[6], probably due to the increase in their bioavailability. In case of octadecane this did not happen. Bioavailability of all three aliphatic hydrocarbons was increased when provided as a mixture to the consortium under saline conditions.

  7. A Weibull characterization for tensile fracture of multicomponent brittle fibers

    NASA Technical Reports Server (NTRS)

    Barrows, R. G.

    1977-01-01

    Necessary to the development and understanding of brittle fiber reinforced composites is a means to statistically describe fiber strength and strain-to-failure behavior. A statistical characterization for multicomponent brittle fibers is presented. The method, which is an extension of usual Weibull distribution procedures, statistically considers the components making up a fiber (e.g., substrate, sheath, and surface) as separate entities and taken together as in a fiber. Tensile data for silicon carbide fiber and for an experimental carbon-boron alloy fiber are evaluated in terms of the proposed multicomponent Weibull characterization.

  8. Supramolecular polymers as dynamic multicomponent cellular uptake carriers.

    PubMed

    Petkau-Milroy, Katja; Sonntag, Michael H; van Onzen, Arthur H A M; Brunsveld, Luc

    2012-05-16

    Supramolecular synthesis represents a flexible approach to the generation of dynamic multicomponent materials with tunable properties. Here, cellular uptake systems based on dynamic supramolecular copolymers have been developed using a combination of differently functionalized discotic molecules. Discotics featuring peripheral amine functionalities that endow the supramolecular polymer with cellular uptake capabilities were readily synthesized. This enabled the uptake of otherwise cell-impermeable discotics via cotransport as a function of supramolecular coassembly. Dynamic multicomponent and multifunctional supramolecular polymers represent a novel and unique platform for modular cellular uptake systems.

  9. Thermal response of integral multicomponent composite thermal protection systems

    NASA Technical Reports Server (NTRS)

    Stewart, D. A.; Leiser, D. B.; Smith, M.; Kolodziej, P.

    1985-01-01

    Integral-multicomponent thermal-protection materials are discussed in terms of their thermal response to an arc-jet airstream. In-depth temperature measurements are compared with predictions from a one-dimensional, finite-difference code using calculated thermal conductivity values derived from an engineering model. The effect of composition, as well as the optical properties of the bonding material between components, on thermal response is discussed. The performance of these integral-multicomponent composite materials is compared with baseline Space Shuttle insulation.

  10. Sensor Arrays from Multicomponent Micropatterned Nanoparticles and Graphene

    DTIC Science & Technology

    2013-10-10

    tetrahydrate in the presence of ammonia into Fe3O4 nanoparticles. The resultant Fe3O4/Au multicomponent micropatterned-graphene films were found to be highly...alkalization of ferrous chloride tetrahydrate in the presence of ammonia into Fe3O4 nanoparticles. The resultant Fe3O4/Au multicomponent...alkalization reaction of ferrous ions with ammonium hydroxide (NH4OH) in the presence of ammonia to form Fe3O4 nanoparticles within the plasma-treated areas

  11. Reappraisal of hydrocarbon biomarkers in Archean rocks.

    PubMed

    French, Katherine L; Hallmann, Christian; Hope, Janet M; Schoon, Petra L; Zumberge, J Alex; Hoshino, Yosuke; Peters, Carl A; George, Simon C; Love, Gordon D; Brocks, Jochen J; Buick, Roger; Summons, Roger E

    2015-05-12

    Hopanes and steranes found in Archean rocks have been presented as key evidence supporting the early rise of oxygenic photosynthesis and eukaryotes, but the syngeneity of these hydrocarbon biomarkers is controversial. To resolve this debate, we performed a multilaboratory study of new cores from the Pilbara Craton, Australia, that were drilled and sampled using unprecedented hydrocarbon-clean protocols. Hopanes and steranes in rock extracts and hydropyrolysates from these new cores were typically at or below our femtogram detection limit, but when they were detectable, they had total hopane (<37.9 pg per gram of rock) and total sterane (<32.9 pg per gram of rock) concentrations comparable to those measured in blanks and negative control samples. In contrast, hopanes and steranes measured in the exteriors of conventionally drilled and curated rocks of stratigraphic equivalence reach concentrations of 389.5 pg per gram of rock and 1,039 pg per gram of rock, respectively. Polycyclic aromatic hydrocarbons and diamondoids, which exceed blank concentrations, exhibit individual concentrations up to 80 ng per gram of rock in rock extracts and up to 1,000 ng per gram of rock in hydropyrolysates from the ultraclean cores. These results demonstrate that previously studied Archean samples host mixtures of biomarker contaminants and indigenous overmature hydrocarbons. Therefore, existing lipid biomarker evidence cannot be invoked to support the emergence of oxygenic photosynthesis and eukaryotes by ∼ 2.7 billion years ago. Although suitable Proterozoic rocks exist, no currently known Archean strata lie within the appropriate thermal maturity window for syngenetic hydrocarbon biomarker preservation, so future exploration for Archean biomarkers should screen for rocks with milder thermal histories.

  12. Reappraisal of hydrocarbon biomarkers in Archean rocks

    PubMed Central

    French, Katherine L.; Hallmann, Christian; Hope, Janet M.; Schoon, Petra L.; Zumberge, J. Alex; Hoshino, Yosuke; Peters, Carl A.; George, Simon C.; Love, Gordon D.; Brocks, Jochen J.; Buick, Roger; Summons, Roger E.

    2015-01-01

    Hopanes and steranes found in Archean rocks have been presented as key evidence supporting the early rise of oxygenic photosynthesis and eukaryotes, but the syngeneity of these hydrocarbon biomarkers is controversial. To resolve this debate, we performed a multilaboratory study of new cores from the Pilbara Craton, Australia, that were drilled and sampled using unprecedented hydrocarbon-clean protocols. Hopanes and steranes in rock extracts and hydropyrolysates from these new cores were typically at or below our femtogram detection limit, but when they were detectable, they had total hopane (<37.9 pg per gram of rock) and total sterane (<32.9 pg per gram of rock) concentrations comparable to those measured in blanks and negative control samples. In contrast, hopanes and steranes measured in the exteriors of conventionally drilled and curated rocks of stratigraphic equivalence reach concentrations of 389.5 pg per gram of rock and 1,039 pg per gram of rock, respectively. Polycyclic aromatic hydrocarbons and diamondoids, which exceed blank concentrations, exhibit individual concentrations up to 80 ng per gram of rock in rock extracts and up to 1,000 ng per gram of rock in hydropyrolysates from the ultraclean cores. These results demonstrate that previously studied Archean samples host mixtures of biomarker contaminants and indigenous overmature hydrocarbons. Therefore, existing lipid biomarker evidence cannot be invoked to support the emergence of oxygenic photosynthesis and eukaryotes by ∼2.7 billion years ago. Although suitable Proterozoic rocks exist, no currently known Archean strata lie within the appropriate thermal maturity window for syngenetic hydrocarbon biomarker preservation, so future exploration for Archean biomarkers should screen for rocks with milder thermal histories. PMID:25918387

  13. Reappraisal of hydrocarbon biomarkers in Archean rocks

    NASA Astrophysics Data System (ADS)

    French, Katherine L.; Hallmann, Christian; Hope, Janet M.; Schoon, Petra L.; Zumberge, J. Alex; Hoshino, Yosuke; Peters, Carl A.; George, Simon C.; Love, Gordon D.; Brocks, Jochen J.; Buick, Roger; Summons, Roger E.

    2015-05-01

    Hopanes and steranes found in Archean rocks have been presented as key evidence supporting the early rise of oxygenic photosynthesis and eukaryotes, but the syngeneity of these hydrocarbon biomarkers is controversial. To resolve this debate, we performed a multilaboratory study of new cores from the Pilbara Craton, Australia, that were drilled and sampled using unprecedented hydrocarbon-clean protocols. Hopanes and steranes in rock extracts and hydropyrolysates from these new cores were typically at or below our femtogram detection limit, but when they were detectable, they had total hopane (<37.9 pg per gram of rock) and total sterane (<32.9 pg per gram of rock) concentrations comparable to those measured in blanks and negative control samples. In contrast, hopanes and steranes measured in the exteriors of conventionally drilled and curated rocks of stratigraphic equivalence reach concentrations of 389.5 pg per gram of rock and 1,039 pg per gram of rock, respectively. Polycyclic aromatic hydrocarbons and diamondoids, which exceed blank concentrations, exhibit individual concentrations up to 80 ng per gram of rock in rock extracts and up to 1,000 ng per gram of rock in hydropyrolysates from the ultraclean cores. These results demonstrate that previously studied Archean samples host mixtures of biomarker contaminants and indigenous overmature hydrocarbons. Therefore, existing lipid biomarker evidence cannot be invoked to support the emergence of oxygenic photosynthesis and eukaryotes by ∼2.7 billion years ago. Although suitable Proterozoic rocks exist, no currently known Archean strata lie within the appropriate thermal maturity window for syngenetic hydrocarbon biomarker preservation, so future exploration for Archean biomarkers should screen for rocks with milder thermal histories.

  14. The Single Pass Multi-component Harvester

    SciTech Connect

    Reed Hoskinson; John R. Hess

    2004-08-01

    collection must be economically advantageous to the producer. To do all that, a single pass multi-component harvester system is most desirable. Results from our first prototype suggest that current combines probably do adequate threshing and that a separate chassis can be developed that does additional separation and that is economically feasible.

  15. Studies of Particle Packings in Mixtures of Pharmaceutical Excipients

    NASA Astrophysics Data System (ADS)

    Bentham, Craig; Dutt, Meenakshi; Hancock, Bruno; Elliott, James

    2005-03-01

    Pharmaceutical powder blends used to generate tablets are complex multicomponent mixtures of the drug powder and excipients which facilitate the delivery of the required drug. The individual constituents of these blends can be noncohesive and cohesive powders. We study the geometric and mechanical characteristics of idealized mixtures of excipient particle packings, for a small but representative number of dry noncohesive particles, generated via gravitational compaction followed by uniaxial compaction. We discuss particle packings in 2- and 3- component mixtures of microcrystalline cellulose (MCC) & lactose and MCC, starch & lactose, respectively. We have computed the evolution of the force and stress distributions in monodisperse and polydisperse mixtures comprised of equal parts of each excipient; comparisons are made with results for particles packings of pure blends of MCC and lactose. We also compute the stress-strain relations for these mixtures. In order to obtain insight into details of the particle packings, we calculate the coordination number, packing fraction, radial distribution functions and contact angle distributions for the various mixtures. The numerical experiments have been performed on spheroidal idealizations of the excipient grains using Discrete Element Method simulations (Dutt et al., 2004 to be published).

  16. Anaerobic Microbial Transformation of Aromatic Hydrocarbons and Mixtures of Aromatic Hydrocarbons and Halogenated Solvents.

    DTIC Science & Technology

    1992-08-25

    Final Technical I FROM 9/30/88 TO 3/31/92w August 25, 19921 149 16. SUPPLEMENTARY NOTATION Six peer- reviewed publications, acknowledging the sponsor...degradation, indicating that the presence of natural organic substrates may preclude anaerobic biodegradation of MAH in situ. Cyclohexane, CT, and...dechlorination rates with all the CB tested, except for the first step of PeCB transformation (reductive dechlorination to TTCB). Toluene, p- cresol , phenol, or

  17. Method and apparatus for synthesizing hydrocarbons

    DOEpatents

    Colmenares, C.A.; Somorjai, G.A.; Maj, J.J.

    1985-04-16

    A method and apparatus for synthesizing a mixture of aliphatic alcohols having five carbons or less is disclosed. An equal molar ratio of CO and H/sub 2/ gases is caused to pass through a ThO/sub 2/ catalyst having a surface area of about 80 to 125 m/sup 2//g. The catalyst further optionally includes Na ions present as substitutional cations in an amount of about 5 to 10 atom %. At a temperature of about 570 to 630/sup 0/K, and at pressures of about 20 to 50 atm, methanol and isobutanol are the predominant products and are produced in amounts of about 90 wt % of the total hydrocarbon mixture. 6 figs.

  18. Simulation of a hydrocarbon fueled scramjet exhaust

    NASA Technical Reports Server (NTRS)

    Leng, J.

    1982-01-01

    Exhaust nozzle flow fields for a fully integrated, hydrocarbon burning scramjet were calculated for flight conditions of M (undisturbed free stream) = 4 at 6.1 km altitude and M (undisturbed free stream) = 6 at 30.5 km altitude. Equilibrium flow, frozen flow, and finite rate chemistry effects are considered. All flow fields were calculated by method of characteristics. Finite rate chemistry results were evaluated by a one dimensional code (Bittker) using streamtube area distributions extracted from the equilibrium flow field, and compared to very slow artificial rate cases for the same streamtube area distribution. Several candidate substitute gas mixtures, designed to simulate the gas dynamics of the real engine exhaust flow, were examined. Two mixtures are found to give excellent simulations of the specified exhaust flow fields when evaluated by the same method of characteristics computer code.

  19. Predicting Multicomponent Adsorption Isotherms in Open-Metal Site Materials Using Force Field Calculations Based on Energy Decomposed Density Functional Theory.

    PubMed

    Heinen, Jurn; Burtch, Nicholas C; Walton, Krista S; Fonseca Guerra, Célia; Dubbeldam, David

    2016-12-12

    For the design of adsorptive-separation units, knowledge is required of the multicomponent adsorption behavior. Ideal adsorbed solution theory (IAST) breaks down for olefin adsorption in open-metal site (OMS) materials due to non-ideal donor-acceptor interactions. Using a density-function-theory-based energy decomposition scheme, we develop a physically justifiable classical force field that incorporates the missing orbital interactions using an appropriate functional form. Our first-principles derived force field shows greatly improved quantitative agreement with the inflection points, initial uptake, saturation capacity, and enthalpies of adsorption obtained from our in-house adsorption experiments. While IAST fails to make accurate predictions, our improved force field model is able to correctly predict the multicomponent behavior. Our approach is also transferable to other OMS structures, allowing the accurate study of their separation performances for olefins/paraffins and further mixtures involving complex donor-acceptor interactions.

  20. ASSESSMENT OF GENOTOXIC ACTIVITY OF PETROLEUM HYDROCARBON-BIOREMEDIATED SOIL

    SciTech Connect

    BRIGMON, ROBIN

    2004-10-20

    The relationship between toxicity and soil contamination must be understood to develop reliable indicators of environmental restoration for bioremediation. Two bacterial rapid bioassays: SOS chromotest and umu-test with and without metabolic activation (S-9 mixture) were used to evaluate genotoxicity of petroleum hydrocarbon-contaminated soil following bioremediation treatment. The soil was taken from an engineered biopile at the Czor Polish oil refinery. The bioremediation process in the biopile lasted 4 years, and the toxicity measurements were done after this treatment. Carcinogens detected in the soil, polyaromatic hydrocarbons (PAHs), were reduced to low concentrations (2 mg/kg dry wt) by the bioremediation process. Genotoxicity was not observed for soils tested with and without metabolic activation by a liver homogenate (S-9 mixture). However, umu-test was more sensitive than SOS-chromotest in the analysis of petroleum hydrocarbon-bioremediated soil. Analytical results of soil used in the bioassays confirmed that the bioremediation process reduced 81 percent of the petroleum hydrocarbons including PAHs. We conclude that the combined test systems employed in this study are useful tools for the genotoxic examination of remediated petroleum hydrocarbon-contaminated soil.

  1. A review of the neurotoxicity risk of selected hydrocarbon fuels.

    PubMed

    Ritchie, G D; Still, K R; Alexander, W K; Nordholm, A F; Wilson, C L; Rossi, J; Mattie, D R

    2001-01-01

    Over 1.3 million civilian and military personnel are occupationally exposed to hydrocarbon fuels, emphasizing gasoline, jet fuel, diesel fuel, or kerosene. These exposures may occur acutely or chronically to raw fuel, vapor, aerosol, or fuel combustion exhaust by dermal, respiratory inhalation, or oral ingestion routes, and commonly occur concurrently with exposure to other chemicals and stressors. Hydrocarbon fuels are complex mixtures of 150-260+ aliphatic and aromatic hydrocarbon compounds containing varying concentrations of potential neurotoxicants including benzene, n-hexane, toluene, xylenes, naphthalene, and certain n-C9-C12 fractions (n-propylbenzene, trimethylbenzene isomers). Due to their natural petroleum base, the chemical composition of different hydrocarbon fuels is not defined, and the fuels are classified according to broad performance criteria such as flash and boiling points, complicating toxicological comparisons. While hydrocarbon fuel exposures occur typically at concentrations below permissible exposure limits for their constituent chemicals, it is unknown whether additive or synergistic interactions may result in unpredicted neurotoxicity. The inclusion of up to six performance additives in existing fuel formulations presents additional neurotoxicity challenge. Additionally, exposures to hydrocarbon fuels, typically with minimal respiratory or dermal protection, range from weekly fueling of personal automobiles to waist-deep immersion of personnel in raw fuel during maintenance of aircraft fuel tanks. Occupational exposures may occur on a near daily basis for from several months to over 20 yr. A number of published studies have reported acute or persisting neurotoxic effects from acute, subchronic, or chronic exposure of humans or animals to hydrocarbon fuels, or to certain constituent chemicals of these fuels. This review summarizes human and animal studies of hydrocarbon fuel-induced neurotoxicity and neurobehavioral consequences. It is

  2. Medicines, shaken and stirred: a critical review on the ecotoxicology of pharmaceutical mixtures.

    PubMed

    Backhaus, Thomas

    2014-11-19

    Analytical monitoring surveys routinely confirm that organisms in the environment are exposed to complex multi-component pharmaceutical mixtures. We are hence tasked with the challenge to take this into consideration when investigating the ecotoxicology of pharmaceuticals. This review first provides a brief overview of the fundamental approaches for mixture toxicity assessment, which is then followed by a critical review on the empirical evidence that is currently at hand on the ecotoxicology of pharmaceutical mixtures. It is concluded that, while the classical concepts of concentration addition and independent action (response addition) provide a robust scientific footing, several knowledge gaps remain. This includes, in particular, the need for more and better empirical data on the effects of pharmaceutical mixtures on soil organisms as well as marine flora and fauna, and exploring the quantitative consequences of toxicokinetic, toxicodynamic and ecological interactions. Increased focus should be put on investigating the ecotoxicology of pharmaceutical mixtures in environmentally realistic settings.

  3. Medicines, shaken and stirred: a critical review on the ecotoxicology of pharmaceutical mixtures

    PubMed Central

    Backhaus, Thomas

    2014-01-01

    Analytical monitoring surveys routinely confirm that organisms in the environment are exposed to complex multi-component pharmaceutical mixtures. We are hence tasked with the challenge to take this into consideration when investigating the ecotoxicology of pharmaceuticals. This review first provides a brief overview of the fundamental approaches for mixture toxicity assessment, which is then followed by a critical review on the empirical evidence that is currently at hand on the ecotoxicology of pharmaceutical mixtures. It is concluded that, while the classical concepts of concentration addition and independent action (response addition) provide a robust scientific footing, several knowledge gaps remain. This includes, in particular, the need for more and better empirical data on the effects of pharmaceutical mixtures on soil organisms as well as marine flora and fauna, and exploring the quantitative consequences of toxicokinetic, toxicodynamic and ecological interactions. Increased focus should be put on investigating the ecotoxicology of pharmaceutical mixtures in environmentally realistic settings. PMID:25405972

  4. Optimal Multicomponent Analysis Using the Generalized Standard Addition Method.

    ERIC Educational Resources Information Center

    Raymond, Margaret; And Others

    1983-01-01

    Describes an experiment on the simultaneous determination of chromium and magnesium by spectophotometry modified to include the Generalized Standard Addition Method computer program, a multivariate calibration method that provides optimal multicomponent analysis in the presence of interference and matrix effects. Provides instructions for…

  5. Multicomponent Droplet Evaporation on Chemical Micro-Patterned Surfaces

    PubMed Central

    He, Minghao; Liao, Dong; Qiu, Huihe

    2017-01-01

    The evaporation and dynamics of a multicomponent droplet on a heated chemical patterned surface were presented. Comparing to the evaporation process of a multicomponent droplet on a homogenous surface, it is found that the chemical patterned surface can not only enhance evaporation by elongating the contact line, but also change the evaporation process from three regimes for the homogenous surface including constant contact line (CCL) regime, constant contact angle (CCA) regime and mix mode (MM) to two regimes, i.e. constant contact line (CCL) and moving contact line (MCL) regimes. The mechanism of contact line stepwise movement in MCL regimes in the microscopic range is investigated in detail. In addition, an improved local force model on the contact line was employed for analyzing the critical receding contact angles on homogenous and patterned surfaces. The analysis results agree well for both surfaces, and confirm that the transition from CCL to MCL regimes indicated droplet composition changes from multicomponent to monocomponent, providing an important metric to predict and control the dynamic behavior and composition of a multicomponent droplet using a patterned surface. PMID:28157229

  6. Essential Unidimensionality Examination for Multicomponent Scales: An Interrelationship Decomposition Approach

    ERIC Educational Resources Information Center

    Raykov, Tenko; Pohl, Steffi

    2013-01-01

    A procedure for examining essential unidimensionality in multicomponent measuring instruments is discussed. The method is based on an application of latent variable modeling and is concerned with the extent to which a common factor for all components of a given scale accounts for their correlations. The approach provides point and interval…

  7. Multicomponent Droplet Evaporation on Chemical Micro-Patterned Surfaces.

    PubMed

    He, Minghao; Liao, Dong; Qiu, Huihe

    2017-02-03

    The evaporation and dynamics of a multicomponent droplet on a heated chemical patterned surface were presented. Comparing to the evaporation process of a multicomponent droplet on a homogenous surface, it is found that the chemical patterned surface can not only enhance evaporation by elongating the contact line, but also change the evaporation process from three regimes for the homogenous surface including constant contact line (CCL) regime, constant contact angle (CCA) regime and mix mode (MM) to two regimes, i.e. constant contact line (CCL) and moving contact line (MCL) regimes. The mechanism of contact line stepwise movement in MCL regimes in the microscopic range is investigated in detail. In addition, an improved local force model on the contact line was employed for analyzing the critical receding contact angles on homogenous and patterned surfaces. The analysis results agree well for both surfaces, and confirm that the transition from CCL to MCL regimes indicated droplet composition changes from multicomponent to monocomponent, providing an important metric to predict and control the dynamic behavior and composition of a multicomponent droplet using a patterned surface.

  8. Multicomponent Droplet Evaporation on Chemical Micro-Patterned Surfaces

    NASA Astrophysics Data System (ADS)

    He, Minghao; Liao, Dong; Qiu, Huihe

    2017-02-01

    The evaporation and dynamics of a multicomponent droplet on a heated chemical patterned surface were presented. Comparing to the evaporation process of a multicomponent droplet on a homogenous surface, it is found that the chemical patterned surface can not only enhance evaporation by elongating the contact line, but also change the evaporation process from three regimes for the homogenous surface including constant contact line (CCL) regime, constant contact angle (CCA) regime and mix mode (MM) to two regimes, i.e. constant contact line (CCL) and moving contact line (MCL) regimes. The mechanism of contact line stepwise movement in MCL regimes in the microscopic range is investigated in detail. In addition, an improved local force model on the contact line was employed for analyzing the critical receding contact angles on homogenous and patterned surfaces. The analysis results agree well for both surfaces, and confirm that the transition from CCL to MCL regimes indicated droplet composition changes from multicomponent to monocomponent, providing an important metric to predict and control the dynamic behavior and composition of a multicomponent droplet using a patterned surface.

  9. Criteria for Modeling in LES of Multicomponent Fuel Flow

    NASA Technical Reports Server (NTRS)

    Bellan, Josette; Selle, Laurent

    2009-01-01

    A report presents a study addressing the question of which large-eddy simulation (LES) equations are appropriate for modeling the flow of evaporating drops of a multicomponent liquid in a gas (e.g., a spray of kerosene or diesel fuel in air). The LES equations are obtained from the direct numerical simulation (DNS) equations in which the solution is computed at all flow length scales, by applying a spatial low-pass filter. Thus, in LES the small scales are removed and replaced by terms that cannot be computed from the LES solution and instead must be modeled to retain the effect of the small scales into the equations. The mathematical form of these models is a subject of contemporary research. For a single-component liquid, there is only one LES formulation, but this study revealed that for a multicomponent liquid, there are two non-equivalent LES formulations for the conservation equations describing the composition of the vapor. Criteria were proposed for selecting the multicomponent LES formulation that gives the best accuracy and increased computational efficiency. These criteria were applied in examination of filtered DNS databases to compute the terms in the LES equations. The DNS databases are from mixing layers of diesel and kerosene fuels. The comparisons resulted in the selection of one of the multicomponent LES formulations as the most promising with respect to all criteria.

  10. Multicomponent Training of Teachers of Students with Severe Disabilities

    ERIC Educational Resources Information Center

    Brown, Phillip; Stephenson, Jennifer; Carter, Mark

    2014-01-01

    Over the last decade, the obligation of general and special educators to utilize evidence-based instructional practices has become more prominent. Research increasingly suggests the failure of didactic teacher training alone to ensure implementation with fidelity of these practices by teachers in their classrooms. Multicomponent training (MCT)…

  11. Neuronal Processing of Complex Mixtures Establishes a Unique Odor Representation in the Moth Antennal Lobe

    PubMed Central

    Kuebler, Linda S.; Olsson, Shannon B.; Weniger, Richard; Hansson, Bill S.

    2011-01-01

    Animals typically perceive natural odor cues in their olfactory environment as a complex mixture of chemically diverse components. In insects, the initial representation of an odor mixture occurs in the first olfactory center of the brain, the antennal lobe (AL). The contribution of single neurons to the processing of complex mixtures in insects, and in particular moths, is still largely unknown. Using a novel multicomponent stimulus system to equilibrate component and mixture concentrations according to vapor pressure, we performed intracellular recordings of projection and interneurons in an attempt to quantitatively characterize mixture representation and integration properties of single AL neurons in the moth. We found that the fine spatiotemporal representation of 2–7 component mixtures among single neurons in the AL revealed a highly combinatorial, non-linear process for coding host mixtures presumably shaped by the AL network: 82% of mixture responding projection neurons and local interneurons showed non-linear spike frequencies in response to a defined host odor mixture, exhibiting an array of interactions including suppression, hypoadditivity, and synergism. Our results indicate that odor mixtures are represented by each cell as a unique combinatorial representation, and there is no general rule by which the network computes the mixture in comparison to single components. On the single neuron level, we show that those differences manifest in a variety of parameters, including the spatial location, frequency, latency, and temporal pattern of the response kinetics. PMID:21772814

  12. Prediction of solubility in nonideal multicomponent systems using the UNIFAC group contribution model.

    PubMed

    Ochsner, A B; Sokoloski, T D

    1985-06-01

    There is a need to identify suitable blends of solvents to dissolve drugs. Empirical approaches, such as trial-and-error and response surface, require several solubility measurements. In this study the UNIFAC method was used to predict solubility in highly nonideal multicomponent systems in which only the solute enthalpy of fusion and melting point must by measured. UNIFAC combines a group contribution approach with the UNIQUAC model for activity coefficients. Parameters characterizing interactions among constituent groups of a molecule have been previously determined from binary vapor pressure data. These tabulated group parameters are used to predict activity coefficients for newly synthesized compounds. These coefficients, together with the ideal solubility, permit a prediction of solubility. The solubility of 4-hexylresorcinol in ethyl acetate, ethyl myristate, and hexane mixtures was both measured and calculated using UNIFAC. The predicted solubilities were within 10% of the experimental solubilities for all but 3 of 21 mixtures. Since the method accounted for positive and negative deviations from ideality in a hydrogen-bonding system of molecules having different sizes, it shows great potential for use in pharmacy.

  13. Superconductivity in aromatic hydrocarbons

    NASA Astrophysics Data System (ADS)

    Kubozono, Yoshihiro; Goto, Hidenori; Jabuchi, Taihei; Yokoya, Takayoshi; Kambe, Takashi; Sakai, Yusuke; Izumi, Masanari; Zheng, Lu; Hamao, Shino; Nguyen, Huyen L. T.; Sakata, Masafumi; Kagayama, Tomoko; Shimizu, Katsuya

    2015-07-01

    'Aromatic hydrocarbon' implies an organic molecule that satisfies the (4n + 2) π-electron rule and consists of benzene rings. Doping solid aromatic hydrocarbons with metals provides the superconductivity. The first discovery of such superconductivity was made for K-doped picene (Kxpicene, five benzene rings). Its superconducting transition temperatures (Tc's) were 7 and 18 K. Recently, we found a new superconducting Kxpicene phase with a Tc as high as 14 K, so we now know that Kxpicene possesses multiple superconducting phases. Besides Kxpicene, we discovered new superconductors such as Rbxpicene and Caxpicene. A most serious problem is that the shielding fraction is ⩽15% for Kxpicene and Rbxpicene, and it is often ∼1% for other superconductors. Such low shielding fractions have made it difficult to determine the crystal structures of superconducting phases. Nevertheless, many research groups have expended a great deal of effort to make high quality hydrocarbon superconductors in the five years since the discovery of hydrocarbon superconductivity. At the present stage, superconductivity is observed in certain metal-doped aromatic hydrocarbons (picene, phenanthrene and dibenzopentacene), but the shielding fraction remains stubbornly low. The highest priority research area is to prepare aromatic superconductors with a high superconducting volume-fraction. Despite these difficulties, aromatic superconductivity is still a core research target and presents interesting and potentially breakthrough challenges, such as the positive pressure dependence of Tc that is clearly observed in some phases of aromatic hydrocarbon superconductors, suggesting behavior not explained by the standard BCS picture of superconductivity. In this article, we describe the present status of this research field, and discuss its future prospects.

  14. Process for the solvent deasphalting of asphaltene-containing hydrocarbons

    SciTech Connect

    Ikematsu, M.; Honzyo, I.; Sakai, K.

    1985-03-05

    A continuous process for solvent deasphalting asphaltene-containing hydrocarbons which comprises mixing (A) 100 parts by weight of asphaltene-containing hydrocarbons with (B) 0.005-0.5 parts by weight of an amorphous silicon dioxide and/or a silicate compound and also with (C) 5-2000 parts by weight of a solvent such as n-heptane, n-hexane, n-heptane or a mixed n-pentane.n-butanol solvent, to form a mixture which is then allowed to stand still to precipitate and separate the asphaltene therefrom thereby obtaining a deasphalted oil.

  15. Low-Temperature Catalytic Process To Produce Hydrocarbons From Sugars

    DOEpatents

    Cortright, Randy D.; Dumesic, James A.

    2005-11-15

    Disclosed is a method of producing hydrogen from oxygenated hydrocarbon reactants, such as methanol, glycerol, sugars (e.g. glucose and xylose), or sugar alcohols (e.g. sorbitol). The method takes place in the condensed liquid phase. The method includes the steps of reacting water and a water-soluble oxygenated hydrocarbon in the presence of a metal-containing catalyst. The catalyst contains a metal selected from the group consisting of Group VIIIB transitional metals, alloys thereof, and mixtures thereof. The disclosed method can be run at lower temperatures than those used in the conventional steam reforming of alkanes.

  16. Quantification of petroleum-type hydrocarbons in avian tissue

    USGS Publications Warehouse

    Gay, M.L.; Belisle, A.A.; Patton, J.F.

    1980-01-01

    Summary: Methods were developed for the analysis of 16 hydrocarbons in avian tissue. Mechanical extraction with pentane was followed by clean-up on Florisil and Silicar. Residues were determined by gas--liquid chromatography and gas-liquid, chromatography-mass spectrometry. The method was applied to the analysis of liver, kidney, fat, and brain tissue of mallard ducks (Anas platyrhynchos) fed a mixture of hydrocarbons. Measurable concentrations of all compounds analyzed were present in all tissues except brain. Highest concentrations were in fat.

  17. TOGA: A TOUGH code for modeling three-phase, multi-component, and non-isothermal processes involved in CO2-based Enhanced Oil Recovery

    SciTech Connect

    Pan, Lehua; Oldenburg, Curtis M.

    2016-10-10

    TOGA is a numerical reservoir simulator for modeling non-isothermal flow and transport of water, CO2, multicomponent oil, and related gas components for applications including CO2-enhanced oil recovery (CO2-EOR) and geologic carbon sequestration in depleted oil and gas reservoirs. TOGA uses an approach based on the Peng-Robinson equation of state (PR-EOS) to calculate the thermophysical properties of the gas and oil phases including the gas/oil components dissolved in the aqueous phase, and uses a mixing model to estimate the thermophysical properties of the aqueous phase. The phase behavior (e.g., occurrence and disappearance of the three phases, gas + oil + aqueous) and the partitioning of non-aqueous components (e.g., CO2, CH4, and n-oil components) between coexisting phases are modeled using K-values derived from assumptions of equal-fugacity that have been demonstrated to be very accurate as shown by comparison to measured data. Models for saturated (water) vapor pressure and water solubility (in the oil phase) are used to calculate the partitioning of the water (H2O) component between the gas and oil phases. All components (e.g., CO2, H2O, and n hydrocarbon components) are allowed to be present in all phases (aqueous, gaseous, and oil). TOGA uses a multiphase version of Darcy’s Law to model flow and transport through porous media of mixtures with up to three phases over a range of pressures and temperatures appropriate to hydrocarbon recovery and geologic carbon sequestration systems. Transport of the gaseous and dissolved components is by advection and Fickian molecular diffusion. New methods for phase partitioning and thermophysical property modeling in TOGA have been validated against experimental data published in the literature for describing phase partitioning and phase behavior. Flow and transport has been verified by testing against related TOUGH2 EOS modules and

  18. Quantitative Hydrocarbon Surface Analysis

    NASA Technical Reports Server (NTRS)

    Douglas, Vonnie M.

    2000-01-01

    The elimination of ozone depleting substances, such as carbon tetrachloride, has resulted in the use of new analytical techniques for cleanliness verification and contamination sampling. The last remaining application at Rocketdyne which required a replacement technique was the quantitative analysis of hydrocarbons by infrared spectrometry. This application, which previously utilized carbon tetrachloride, was successfully modified using the SOC-400, a compact portable FTIR manufactured by Surface Optics Corporation. This instrument can quantitatively measure and identify hydrocarbons from solvent flush of hardware as well as directly analyze the surface of metallic components without the use of ozone depleting chemicals. Several sampling accessories are utilized to perform analysis for various applications.

  19. Multicomponent Diffusion between Felsic and Silicic Melts: Insights from Tektites and Experiments

    NASA Astrophysics Data System (ADS)

    Macris, C. A.; Asimow, P. D.; Zhang, Y.; Badro, J.; Stolper, E. M.; Eiler, J. M.

    2014-12-01

    Tektites (natural glasses formed as quenched impact melt ejecta) commonly contain inclusions of nearly pure silica glass ("lechatelierite") thought to be quenched from molten silica produced by melting of quartz grains. We investigated chemical diffusion between lechatelierite (~100% SiO2) and surrounding felsic glass (~73% SiO2) in a natural indochinite tektite and in experimental analogues. We discovered concentration profiles of major elements across lechatelierite-felsic glass contacts that reflect diffusion between the two melts at high T as the they followed a ballistic trajectory prior to quenching. The profiles provide information on multicomponent diffusion at the high-silica end of composition space and on the thermal histories of tektites. To reproduce the profiles, we undertook a series of high T melting experiments using an aerodynamic levitation laser furnace. A starting mixture of powdered natural tektite plus quartz grains was exposed to temperatures of 1800-2400˚C for 1-120 s. Direct comparison of concentration profiles between the indochinite and experiments reveals a best match at 2200˚C and 50 s. This experiment successfully reproduced all major aspects of the concentration profiles observed in the natural sample including diffusion length scale, asymmetry, order of steepness of major element profiles, and uphill diffusion of K2O. Not enough information is available to model the full multicomponent diffusion problem, but SiO2 and Al2O3 concentration profiles from lechatelierite to surrounding felsic glass in the experiments can be fit well as a diffusion couple between silica melt and adjacent felsic melt using an effective binary diffusion approach and assuming that the effective binary SiO2 and Al2O3 diffusivities depend exponentially on SiO2 concentration. Further quantification of the diffusion behavior should allow constraints on the thermal histories of tektites.

  20. Timing of pathogen adaptation to a multicomponent treatment.

    PubMed

    Bourget, Romain; Chaumont, Loïc; Sapoukhina, Natalia

    2013-01-01

    The sustainable use of multicomponent treatments such as combination therapies, combination vaccines/chemicals, and plants carrying multigenic resistance requires an understanding of how their population-wide deployment affects the speed of the pathogen adaptation. Here, we develop a stochastic model describing the emergence of a mutant pathogen and its dynamics in a heterogeneous host population split into various types by the management strategy. Based on a multi-type Markov birth and death process, the model can be used to provide a basic understanding of how the life-cycle parameters of the pathogen population, and the controllable parameters of a management strategy affect the speed at which a pathogen adapts to a multicomponent treatment. Our results reveal the importance of coupling stochastic mutation and migration processes, and illustrate how their stochasticity can alter our view of the principles of managing pathogen adaptive dynamics at the population level. In particular, we identify the growth and migration rates that allow pathogens to adapt to a multicomponent treatment even if it is deployed on only small proportions of the host. In contrast to the accepted view, our model suggests that treatment durability should not systematically be identified with mutation cost. We show also that associating a multicomponent treatment with defeated monocomponent treatments can be more durable than associating it with intermediate treatments including only some of the components. We conclude that the explicit modelling of stochastic processes underlying evolutionary dynamics could help to elucidate the principles of the sustainable use of multicomponent treatments in population-wide management strategies intended to impede the evolution of harmful populations.

  1. Comparative analysis of metagenomes from three methanogenic hydrocarbon-degrading enrichment cultures with 41 environmental samples

    PubMed Central

    Tan, Boonfei; Jane Fowler, S; Laban, Nidal Abu; Dong, Xiaoli; Sensen, Christoph W; Foght, Julia; Gieg, Lisa M

    2015-01-01

    Methanogenic hydrocarbon metabolism is a key process in subsurface oil reservoirs and hydrocarbon-contaminated environments and thus warrants greater understanding to improve current technologies for fossil fuel extraction and bioremediation. In this study, three hydrocarbon-degrading methanogenic cultures established from two geographically distinct environments and incubated with different hydrocarbon substrates (added as single hydrocarbons or as mixtures) were subjected to metagenomic and 16S rRNA gene pyrosequencing to test whether these differences affect the genetic potential and composition of the communities. Enrichment of different putative hydrocarbon-degrading bacteria in each culture appeared to be substrate dependent, though all cultures contained both acetate- and H2-utilizing methanogens. Despite differing hydrocarbon substrates and inoculum sources, all three cultures harbored genes for hydrocarbon activation by fumarate addition (bssA, assA, nmsA) and carboxylation (abcA, ancA), along with those for associated downstream pathways (bbs, bcr, bam), though the cultures incubated with hydrocarbon mixtures contained a broader diversity of fumarate addition genes. A comparative metagenomic analysis of the three cultures showed that they were functionally redundant despite their enrichment backgrounds, sharing multiple features associated with syntrophic hydrocarbon conversion to methane. In addition, a comparative analysis of the culture metagenomes with those of 41 environmental samples (containing varying proportions of methanogens) showed that the three cultures were functionally most similar to each other but distinct from other environments, including hydrocarbon-impacted environments (for example, oil sands tailings ponds and oil-affected marine sediments). This study provides a basis for understanding key functions and environmental selection in methanogenic hydrocarbon-associated communities. PMID:25734684

  2. Comparative analysis of metagenomes from three methanogenic hydrocarbon-degrading enrichment cultures with 41 environmental samples.

    PubMed

    Tan, Boonfei; Fowler, S Jane; Abu Laban, Nidal; Dong, Xiaoli; Sensen, Christoph W; Foght, Julia; Gieg, Lisa M

    2015-09-01

    Methanogenic hydrocarbon metabolism is a key process in subsurface oil reservoirs and hydrocarbon-contaminated environments and thus warrants greater understanding to improve current technologies for fossil fuel extraction and bioremediation. In this study, three hydrocarbon-degrading methanogenic cultures established from two geographically distinct environments and incubated with different hydrocarbon substrates (added as single hydrocarbons or as mixtures) were subjected to metagenomic and 16S rRNA gene pyrosequencing to test whether these differences affect the genetic potential and composition of the communities. Enrichment of different putative hydrocarbon-degrading bacteria in each culture appeared to be substrate dependent, though all cultures contained both acetate- and H2-utilizing methanogens. Despite differing hydrocarbon substrates and inoculum sources, all three cultures harbored genes for hydrocarbon activation by fumarate addition (bssA, assA, nmsA) and carboxylation (abcA, ancA), along with those for associated downstream pathways (bbs, bcr, bam), though the cultures incubated with hydrocarbon mixtures contained a broader diversity of fumarate addition genes. A comparative metagenomic analysis of the three cultures showed that they were functionally redundant despite their enrichment backgrounds, sharing multiple features associated with syntrophic hydrocarbon conversion to methane. In addition, a comparative analysis of the culture metagenomes with those of 41 environmental samples (containing varying proportions of methanogens) showed that the three cultures were functionally most similar to each other but distinct from other environments, including hydrocarbon-impacted environments (for example, oil sands tailings ponds and oil-affected marine sediments). This study provides a basis for understanding key functions and environmental selection in methanogenic hydrocarbon-associated communities.

  3. Cometabolic mineralization of benzo[a]pyrene caused by hydrocarbon additions to soil

    SciTech Connect

    Kanaly, R.A.; Bartha, R.

    1999-10-01

    The mineralization of [7-{sup 14}C]benzo[a]pyrene (BaP) in soil was investigated in response to additions of individual hydrocarbons, defined hydrocarbon mixtures, crude oil, and crude oil fractions. Neither substantial BaP mineralization nor enrichment of BaP degraders occurred in BaP-spiked soil in the absence of a suitable hydrocarbon supplement. Crude oil, the saturated and aromatic class components of crude oil, the distillates heating oil, jet fuel, and diesel fuel supported up to 60% mineralization of 80 {micro}g [7-{sup 14}C]BaP per gram of soil in 40 d. Neither single hydrocarbons nor defined hydrocarbon mixtures containing normal and branched alkanes, alicyclics, and aromatics supported comparable BaP mineralization. Evolution of {sup 14}CO{sub 2} occurred after lag periods characteristic to specific petroleum products and their concentrations. Time required for microbial proliferation, hydrocarbon toxicity, and competitive inhibition might have contributed to these lag periods, but the complete inhibition of BaP mineralization by diesel-fuel vapors pointed to a dominant role of competitive inhibition. A lack of radiocarbon incorporation into soil biomass from [7-{sup 14}C]BaP indicated that at least the initial steps of BaP biodegradation in soil were cometabolic in nature. Suitable hydrocarbon mixtures not only supported BaP mineralization by serving as primary substrates, but also enhanced BaP bioavailability by dissolving this hydrophobic solid.

  4. CHANGES IN GENE EXPRESSION PROFILE FOLLOWING SHORT-TERM EXPOSURE TO AN ENVIRONMENTALLY RELEVANT MIXTURE OF PHAHS

    EPA Science Inventory

    Changes in gene expression profile following short-term exposure to an environmentally relevant mixture of PHAHs
    Polyhalogenated aromatic hydrocarbons (PHAH) including, polychlorinated biphenyls (PCBs), polychlorinated dibenzodioxins (PCDDS) and polychlorinated dibenzofurans...

  5. Gradient-driven diffusion and pattern formation in crowded mixtures

    NASA Astrophysics Data System (ADS)

    Nandigrami, Prithviraj; Grove, Brandy; Konya, Andrew; Selinger, Robin L. B.

    2017-02-01

    Gradient-driven diffusion in crowded, multicomponent mixtures is a topic of high interest because of its role in biological processes such as transport in cell membranes. In partially phase-separated solutions, gradient-driven diffusion affects microstructure, which in turn affects diffusivity; a key question is how this complex coupling controls both transport and pattern formation. To examine these mechanisms, we study a two-dimensional multicomponent lattice gas model, where "tracer" molecules diffuse between a source and a sink separated by a solution of sticky "crowder" molecules that cluster to form dynamically evolving obstacles. In the high-temperature limit, crowders and tracers are miscible, and transport may be predicted analytically. At intermediate temperatures, crowders phase separate into clusters that drift toward the tracer sink. As a result, steady-state tracer diffusivity depends nonmonotonically on both temperature and crowder density, and we observe a variety of complex microstructures. In the low-temperature limit, crowders rapidly aggregate to form obstacles that are kinetically arrested; if crowder density is near the percolation threshold, resulting tracer diffusivity shows scaling behavior with the same scaling exponent as the random resistor network model. Though highly idealized, this simple model reveals fundamental mechanisms governing coupled gradient-driven diffusion, phase separation, and microstructural evolution in crowded mixtures.

  6. Multicomponent reactive transport in an in situ zero-valent iron cell

    SciTech Connect

    Yabusaki, Steven B. ); Cantrell, Kirk J. ); Sass, Bruce; Steefel, Carl

    2000-12-01

    Data collected from a field study of in situ zero-valent iron treatment for TCE were analyzed in the context of coupled transport and reaction processes. The focus of this analysis was to understand the behavior of chemical components, including contaminants, in groundwater transported through the iron cell of a pilot-scale funnel and gate treatment system. A multicomponent reactive transport simulator was used to simultaneously model mobile and nonmobile components undergoing equilibrium and kinetic reactions including TCE degradation, parallel iron dissolution reactions, precipitation of secondary minerals, and complexation reactions. The resulting mechanistic model of coupled processes reproduced solution chemistry behavior observed in the iron cell with a minimum of calibration. These observations included the destruction of TCE and cis-1,2-DCE; increases in pH and hydrocarbons; and decreases in EH, alkalinity, dissolved O2 and CO2, and major ions (i.e., Ca, Mg, Cl, sulfate, nitrate). Mineral precipitation in the iron zone was critical to correctly predicting these behaviors. The dominant precipitation products were ferrous hydroxide, siderite, aragonite, brucite, and iron sulfide. In the first few centimeters of the reactive iron cell, these precipitation products are predicted to account for a 3% increase in mineral volume per year, which could have implications for the longevity of favorable barrier hydraulics and reactivity. The inclusion of transport was key to understanding the interplay between rates of transport and rates of reaction in the field.

  7. Microbial biodegradation of polyaromatic hydrocarbons.

    PubMed

    Peng, Ri-He; Xiong, Ai-Sheng; Xue, Yong; Fu, Xiao-Yan; Gao, Feng; Zhao, Wei; Tian, Yong-Sheng; Yao, Quan-Hong

    2008-11-01

    Polycyclic aromatic hydrocarbons (PAHs) are widespread in various ecosystems and are pollutants of great concern due to their potential toxicity, mutagenicity and carcinogenicity. Because of their hydrophobic nature, most PAHs bind to particulates in soil and sediments, rendering them less available for biological uptake. Microbial degradation represents the major mechanism responsible for the ecological recovery of PAH-contaminated sites. The goal of this review is to provide an outline of the current knowledge of microbial PAH catabolism. In the past decade, the genetic regulation of the pathway involved in naphthalene degradation by different gram-negative and gram-positive bacteria was studied in great detail. Based on both genomic and proteomic data, a deeper understanding of some high-molecular-weight PAH degradation pathways in bacteria was provided. The ability of nonligninolytic and ligninolytic fungi to transform or metabolize PAH pollutants has received considerable attention, and the biochemical principles underlying the degradation of PAHs were examined. In addition, this review summarizes the information known about the biochemical processes that determine the fate of the individual components of PAH mixtures in polluted ecosystems. A deeper understanding of the microorganism-mediated mechanisms of catalysis of PAHs will facilitate the development of new methods to enhance the bioremediation of PAH-contaminated sites.

  8. Aliphatic hydrocarbons in Great Barrier Reef organisms and environment

    NASA Astrophysics Data System (ADS)

    Coates, M.; Connell, D. W.; Bodero, J.; Miller, G. J.; Back, R.

    1986-07-01

    This investigation was undertaken to assess the chemical nature, occurrence, and possible origin of petroleum hydrocarbons in the Great Barrier Reef ecosystem. Aliphatic hydrocarbons in surface sediments, water, and a suite of seven species from widely separated coral reefs in the Great Barrier Reef area were analysed by gas chromatography, and by gas chromatography coupled with mass spectrometry. The hydrocarbons found were substantially of biogenic origin. The major components were n-pentadecane, n-heptadecane, pristane and mono-alkenes based on heptadecane, and were believed to originate from benthic algae and phytoplankton. There was no evidence to suggest that lipid content had any influence on hydrocarbon content. Hydrocarbons from the organisms and sediments have characteristic composition patterns which would be altered by the presence of petroleum hydrocarbons. An unresolved complex mixture, usually considered indicative of petroleum contamination, was found in greater than trace amounts only in Holothuria (sea cucumber) and Acropora (coral) from the Capricorn Group, and in some sediment samples from the Capricorn Group and Lizard Island area.

  9. Effect of hydrocarbons on plasma treatment of NOx

    SciTech Connect

    Penetrante, B.M.; Pitz, W.J.; Hsaio, M.C.; Merritt, B.T.; Vogtlin, G.E.

    1997-12-31

    Lean burn gasoline engine exhausts contain a significant amount of hydrocarbons in the form of propene. Diesel engine exhausts contain little gaseous hydrocarbon; however, they contain a significant amount of liquid-phase hydrocarbons (known as the volatile organic fraction) in the particulates. The objective of this paper is to examine the fate of NO{sub x} when an exhaust gas mixture that contains hydrocarbons is subjected to a plasma. The authors will show that the hydrocarbons promote the oxidation of NO to NO{sub 2}, but not the reduction of NO to N{sub 2}. The oxidation of NO to NO{sub 2} is strongly coupled with the hydrocarbon oxidation chemistry. This result suggests that gas-phase reactions in the plasma alone cannot lead to the chemical reduction of NO{sub x}. Any reduction of NO{sub x} to N{sub 2} can only be accomplished through heterogeneous reactions of NO{sub 2} with surfaces or particulates.

  10. Zeroing in on hydrocarbons

    SciTech Connect

    Roest, I.P.B. van der; Brasser, D.J.S.; Wagebaert, A.P.J.; Stam, P.H.

    1997-05-01

    The increasing costs of remediating contaminated sites has stimulated research for cost-reducing techniques in soil investigation and cleanup techniques. MAP Environmental Research has developed a technology using ground penetrating radar in combination with in house developed software to locate and define the extent of hydrocarbon contamination. This article discusses the new technology. 2 figs.

  11. Hydrocarbon options emerge

    SciTech Connect

    Fairley, P.

    1995-11-01

    Europe stole the scene at last week`s International Chlorofluorocarbon (CFC) and Halon Alternatives Conference in Washington as attendees learned more about an accelerating shift to low-cost hydrocarbon refrigerants by European equipment manufacturers. Udo Wenning, representing German refrigerator market leader Bosch-Siemens, told the conference that hydrocarbons-isobutane as refrigerant and cyclopentane to blow the insulating foam-are now used in 90% of German production. Wenning says that in all performance parameters, hydrocarbons match the hydrochlorofluorocarbon (HCFC) and hydrofluorocarbon (HFC) replacements favored in the U.S. and Japan and that, unlike HCFCs and HFCs they have low global warming potential. Their Achille`s heel is flammability, Wenning says. American equipment manufacturers aiming to sell a new generation of equipment designed for the new HFC refrigerants sought to amplify concern over flammability at the conference. {open_quotes}In a society as litigious as ours, we do not see a future for flammable refrigerants,{close_quotes} says a representative of air conditioner manufacturer Carrier. Hydrocarbon supporters such as Greenpeace say the risks are mananageable.

  12. Optrode for sensing hydrocarbons

    DOEpatents

    Miller, Holly; Milanovich, Fred P.; Hirschfeld, Tomas B.; Miller, Fred S.

    1988-01-01

    A two-phase system employing the Fujiwara reaction is provided for the fluorometric detection of halogenated hydrocarbons. A fiber optic is utilized to illuminate a column of pyridine trapped in a capillary tube coaxially attached at one end to the illuminating end of the fiber optic. A strongly alkaline condition necessary for the reaction is maintained by providing a reservoir of alkali in contact with the column of pyridine, the surface of contact being adjacent to the illuminating end of the fiber optic. A semipermeable membrane caps the other end of the capillary tube, the membrane being preferentially permeable to the halogenated hydrocarbon and but preferentially impermeable to water and pyridine. As the halogenated hydrocarbon diffuses through the membrane and into the column of pyridine, fluorescent reaction products are formed. Light propagated by the fiber optic from a light source, excites the fluorescent products. Light from the fluorescence emission is also collected by the same fiber optic and transmitted to a detector. The intensity of the fluorescence gives a measure of the concentration of the halogenated hydrocarbons.

  13. Optrode for sensing hydrocarbons

    DOEpatents

    Miller, Holly; Milanovich, Fred P.; Hirschfeld, Tomas B.; Miller, Fred S.

    1987-01-01

    A two-phase system employing the Fujiwara reaction is provided for the fluorometric detection of halogenated hydrocarbons. A fiber optic is utilized to illuminate a column of pyridine trapped in a capillary tube coaxially attached at one end to the illuminating end of the fiber optic. A strongly alkaline condition necessary for the reaction is maintained by providing a reservoir of alkali in contact with the column of pyridine, the surface of contact being adjacent to the illuminating end of the fiber optic. A semipermeable membrane caps the other end of the capillary tube, the membrane being preferentially permeable to the halogenated hydrocarbon and but preferentially impermeable to water and pyridine. As the halogenated hydrocarbon diffuses through the membrane and into the column of pyridine, fluorescent reaction products are formed. Light propagated by the fiber optic from a light source, excites the fluorescent products. Light from the fluorescence emission is also collected by the same fiber optic and transmitted to a detector. The intensity of the fluorescence gives a measure of the concentration of the halogenated hydrocarbons.

  14. Optrode for sensing hydrocarbons

    DOEpatents

    Miller, H.; Milanovich, F.P.; Hirschfeld, T.B.; Miller, F.S.

    1987-05-19

    A two-phase system employing the Fujiwara reaction is provided for the fluorometric detection of halogenated hydrocarbons. A fiber optic is utilized to illuminate a column of pyridine trapped in a capillary tube coaxially attached at one end to the illuminating end of the fiber optic. A strongly alkaline condition necessary for the reaction is maintained by providing a reservoir of alkali in contact with the column of pyridine, the surface of contact being adjacent to the illuminating end of the fiber optic. A semipermeable membrane caps the other end of the capillary tube, the membrane being preferentially permeable to the halogenated hydrocarbon but preferentially impermeable to water and pyridine. As the halogenated hydrocarbon diffuses through the membrane and into the column of pyridine, fluorescent reaction products are formed. Light propagated by the fiber optic from a light source, excites the fluorescent products. Light from the fluorescence emission is also collected by the same fiber optic and transmitted to a detector. The intensity of the fluorescence gives a measure of the concentration of the halogenated hydrocarbons. 6 figs.

  15. Optrode for sensing hydrocarbons

    DOEpatents

    Miller, H.; Milanovich, F.P.; Hirschfeld, T.B.; Miller, F.S.

    1988-09-13

    A two-phase system employing the Fujiwara reaction is provided for the fluorometric detection of halogenated hydrocarbons. A fiber optic is utilized to illuminate a column of pyridine trapped in a capillary tube coaxially attached at one end to the illuminating end of the fiber optic. A strongly alkaline condition necessary for the reaction is maintained by providing a reservoir of alkali in contact with the column of pyridine, the surface of contact being adjacent to the illuminating end of the fiber optic. A semipermeable membrane caps the other end of the capillary tube, the membrane being preferentially permeable to the halogenated hydrocarbon and but preferentially impermeable to water and pyridine. As the halogenated hydrocarbon diffuses through the membrane and into the column of pyridine, fluorescent reaction products are formed. Light propagated by the fiber optic from a light source, excites the fluorescent products. Light from the fluorescence emission is also collected by the same fiber optic and transmitted to a detector. The intensity of the fluorescence gives a measure of the concentration of the halogenated hydrocarbons. 5 figs.

  16. Polycyclic hydrocarbons and cancer

    SciTech Connect

    Gelboin, H.V.P; Ts'o, P.O.P.

    1981-01-01

    This book is Volume 3 of a three-volume series. It discusses polynuclear aromatic hydrocarbons (PAHs) in the marine environment, various PAH dihydrodiols, certain enzyme reactions, carcinogenesis modifications, and tumor promotion. PAH epidemiology for quantifying cigarette smoking and air pollution risks is also covered. (JMT)

  17. Apparatus and methods for hydrocarbon extraction

    DOEpatents

    Bohnert, George W.; Verhulst, Galen G.

    2016-04-26

    Systems and methods for hydrocarbon extraction from hydrocarbon-containing material. Such systems and methods relate to extracting hydrocarbon from hydrocarbon-containing material employing a non-aqueous extractant. Additionally, such systems and methods relate to recovering and reusing non-aqueous extractant employed for extracting hydrocarbon from hydrocarbon-containing material.

  18. Hydrocarbonization research: completion report

    SciTech Connect

    Youngblood, E.L.; Cochran, H.D. Jr.; Westmoreland, P.R.; Brown, C.H. Jr.; Oswald, G.E.; Barker, R.E.

    1981-01-01

    Hydrocarbonization is a relatively simple process used for producing oil, substitute natural gas, and char by heating coal under a hydrogen-rich atmosphere. This report describes studies that were performed in a bench-scale hydrocarbonization system at Oak Ridge National Laboratory (ORNL) during the period 1975 to 1978. The results of mock-up studies, coal metering valve and flowmeter development, and supporting work in an atmospheric hydrocarbonization system are also described. Oil, gas, and char yields were determined by hydrocarbonization of coal in a 0.1-m-diam fluidized-bed reactor operated at a pressure of 2170 kPa and at temperatures ranging from 694 to 854 K. The nominal coal feed rate was 4.5 kg/h. Wyodak subbituminous coal was used for most of the experiments. A maximum oil yield of approx. 21% based on moisture- and ash-free (maf) coal was achieved in the temperature range of 810 to 840 K. Recirculating fluidized-bed, uniformly fluidized-bed, and rapid hydropyrolysis reactors were used. A series of operability tests was made with Illinois No. 6 coal to determine whether caking coal could be processed in the recirculating fluidized-bed reactor. These tests were generally unsuccessful because of agglomeration and caking problems; however, these problems were eliminated by the use of chemically pretreated coal. Hydrocarbonization experiments were carried out with Illinois No. 6 coal that had been pretreated with CaO-NaOH, Na/sub 2/CO/sub 3/, and CaO-Na/sub 2/CO/sub 3/. Oil yields of 14, 24, and 21%, respectively, were obtained from the runs with treated coal. Gas and char yield data and the composition of the oil, gas, and char products are presented.

  19. Reconstructing metabolic pathways of hydrocarbon-degrading bacteria from the Deepwater Horizon oil spill.

    PubMed

    Dombrowski, Nina; Donaho, John A; Gutierrez, Tony; Seitz, Kiley W; Teske, Andreas P; Baker, Brett J

    2016-05-09

    The Deepwater Horizon blowout in the Gulf of Mexico in 2010, one of the largest marine oil spills(1), changed bacterial communities in the water column and sediment as they responded to complex hydrocarbon mixtures(2-4). Shifts in community composition have been correlated to the microbial degradation and use of hydrocarbons(2,5,6), but the full genetic potential and taxon-specific metabolisms of bacterial hydrocarbon degraders remain unresolved. Here, we have reconstructed draft genomes of marine bacteria enriched from sea surface and deep plume waters of the spill that assimilate alkane and polycyclic aromatic hydrocarbons during stable-isotope probing experiments, and we identify genes of hydrocarbon degradation pathways. Alkane degradation genes were ubiquitous in the assembled genomes. Marinobacter was enriched with n-hexadecane, and uncultured Alpha- and Gammaproteobacteria populations were enriched in the polycyclic-aromatic-hydrocarbon-degrading communities and contained a broad gene set for degrading phenanthrene and naphthalene. The repertoire of polycyclic aromatic hydrocarbon use varied among different bacterial taxa and the combined capabilities of the microbial community exceeded those of its individual components, indicating that the degradation of complex hydrocarbon mixtures requires the non-redundant capabilities of a complex oil-degrading community.

  20. Metabolic responses of Rhodococcus erythropolis PR4 grown on diesel oil and various hydrocarbons.

    PubMed

    Laczi, Krisztián; Kis, Ágnes; Horváth, Balázs; Maróti, Gergely; Hegedüs, Botond; Perei, Katalin; Rákhely, Gábor

    2015-11-01

    Rhodococcus erythropolis PR4 is able to degrade diesel oil, normal-, iso- and cycloparaffins and aromatic compounds. The complete DNA content of the strain was previously sequenced and numerous oxygenase genes were identified. In order to identify the key elements participating in biodegradation of various hydrocarbons, we performed a comparative whole transcriptome analysis of cells grown on hexadecane, diesel oil and acetate. The transcriptomic data for the most prominent genes were validated by RT-qPCR. The expression of two genes coding for alkane-1-monooxygenase enzymes was highly upregulated in the presence of hydrocarbon substrates. The transcription of eight phylogenetically diverse cytochrome P450 (cyp) genes was upregulated in the presence of diesel oil. The transcript levels of various oxygenase genes were determined in cells grown in an artificial mixture, containing hexadecane, cycloparaffin and aromatic compounds and six cyp genes were induced by this hydrocarbon mixture. Five of them were not upregulated by linear and branched hydrocarbons. The expression of fatty acid synthase I genes was downregulated by hydrocarbon substrates, indicating the utilization of external alkanes for fatty acid synthesis. Moreover, the transcription of genes involved in siderophore synthesis, iron transport and exopolysaccharide biosynthesis was also upregulated, indicating their important role in hydrocarbon metabolism. Based on the results, complex metabolic response profiles were established for cells grown on various hydrocarbons. Our results represent a functional annotation of a rhodococcal genome, provide deeper insight into molecular events in diesel/hydrocarbon utilization and suggest novel target genes for environmental monitoring projects.

  1. Mantle hydrocarbons: Abiotic or biotic?

    SciTech Connect

    Sugisaki, Ryuichi; Mimura, Koichi

    1994-06-01

    Analyses of 227 rocks from fifty localities throughout the world showed that mantle derived rocks such as tectonized peridotites in ophiolite sequences (tectonites) and peridotite xenoliths in alkali basalts contain heavier hydrocarbons (n-alkanes), whereas igneous rocks produced by magmas such as gabbro and granite lack them. The occurrence of hydrocarbons indicates that they were not derived either from laboratory contamination or from field contamination; these compounds found in the mantle-derived rocks are called here {open_quotes}mantle hydrocarbons.{close_quotes} The existence of hydrocarbons correlates with petrogenesis. For example, peridotite cumulates produced by magmatic differentiation lack hydrocarbons whereas peridotite xenoliths derived from the mantle contain them. Gas chromatographic-mass spectrometric records of the mantle hydrocarbons resemble those of aliphatics in meteorites and in petroleum. Features of the hydrocarbons are that (a) the mantle hydrocarbons reside mainly along grain boundaries and in fluid inclusions of minerals; (b) heavier isoprenoids such as pristane and phytane are present; and (c) {delta}{sup 13}C of the mantle hydrocarbons is uniform (about {minus}27{per_thousand}). Possible origins for the mantle hydrocarbons are as follows. (1) They were inorganically synthesized by Fischer-Tropsch type reaction in the mantle. (2) They were delivered by meteorites and comets to the early Earth. (3) They were recycled by subduction. The mantle hydrocarbons in the cases of (1) and (2) are abiogenic and those in (3) are mainly biogenic. It appears that hydrocarbons may survive high pressures and temperatures in the mantle, but they are decomposed into lighter hydrocarbon gases such as CH{sub 4} at lower pressures when magmas intrude into the crust; consequently, peridotite cumulates do not contain heavier hydrocarbons but possess hydrocarbon gases up to C{sub 4}H{sub 10}. 76 refs., 5 figs., 3 tabs.

  2. Mantle hydrocarbons: abiotic or biotic?

    PubMed

    Sugisaki, R; Mimura, K

    1994-06-01

    Analyses of 227 rocks from fifty localities throughout the world showed that mantle derived rocks such as tectonized peridotites in ophiolite sequences (tectonites) arid peridotite xenoliths in alkali basalts contain heavier hydrocarbons (n-alkanes), whereas igneous rocks produced by magmas such as gabbro arid granite lack them. The occurrence of hydrocarbons indicates that they were not derived either from laboratory contamination or from held contamination; these compounds found in the mantle-derived rocks are called here "mantle hydrocarbons." The existence of hydrocarbons correlates with petrogenesis. For example, peridotite cumulates produced by magmatic differentiation lack hydrocarbons whereas peridotite xenoliths derived from the mantle contain them. Gas chromatographic-mass spectrometric records of the mantle hydrocarbons resemble those of aliphatics in meteorites and in petroleum. Features of the hydrocarbons are that (a) the mantle hydrocarbons reside mainly along grain boundaries and in fluid inclusions of minerals; (b) heavier isoprenoids such as pristane and phytane are present; and (c) delta 13C of the mantle hydrocarbons is uniform (about -27%). Possible origins for the mantle hydrocarbons are as follows. (1) They were in organically synthesized by Fischer-Tropsch type reaction in the mantle. (2) They were delivered by meteorites and comets to the early Earth. (3) They were recycled by subduction. The mantle hydrocarbons in the cases of (1) and (2) are abiogenic and those in (3) are mainly biogenic. It appears that hydrocarbons may survive high pressures and temperatures in the mantle, but they are decomposed into lighter hydrocarbon gases such as CH4 at lower pressures when magmas intrude into the crust; consequently, peridotite cumulates do not contain heavier hydrocarbons but possess hydrocarbon gases up to C4H10.

  3. Vaporization modeling of petroleum-biofuel drops using a hybrid multi-component approach

    SciTech Connect

    Zhang, Lei; Kong, Song-Charng

    2010-11-15

    Numerical modeling of the vaporization characteristics of multi-component fuel mixtures is performed in this study. The fuel mixtures studied include those of binary components, biodiesel, diesel-biodiesel, and gasoline-ethanol. The use of biofuels has become increasingly important for reasons of environmental sustainability. Biofuels are often blended with petroleum fuels, and the detailed understanding of the vaporization process is essential to designing a clean and efficient combustion system. In this study, a hybrid vaporization model is developed that uses continuous thermodynamics to describe petroleum fuels and discrete components to represent biofuels. The model is validated using the experimental data of n-heptane, n-heptane-n-decane mixture, and biodiesel. Since biodiesel properties are not universal due to the variation in feedstock, methods for predicting biodiesel properties based on the five dominant fatty acid components are introduced. Good levels of agreement in the predicted and measured drop size histories are obtained. Furthermore, in modeling the diesel-biodiesel drop, results show that the drop lifetime increases with the biodiesel concentration in the blend. During vaporization, only the lighter components of diesel fuel vaporize at the beginning. Biodiesel components do not vaporize until some time during the vaporization process. On the other hand, results of gasoline-ethanol drops indicate that both fuels start to vaporize once the process begins. At the beginning, the lighter components of gasoline have a slightly higher vaporization rate than ethanol. After a certain time, ethanol vaporizes faster than the remaining gasoline components. At the end, the drop reduces to a regular gasoline drop with heavier components. Overall, the drop lifetime increases as the concentration of ethanol increases in the drop due to the higher latent heat. (author)

  4. DETERMINATION AND QUANTIFICATION OF NON-AQUEOUS PHASE LIQUID MIXTURES IN ENVIRONMENTAL MEDIA

    SciTech Connect

    Rucker, G

    2006-09-22

    It is important to recognize the presence of Non-Aqueous Phase Liquids (NAPLs) in soils at a waste site in order to design and construct a successful remediation system. NAPLs often manifest as a complex, multi-component mixture of organic compounds that can occur in environmental media, such as vadose zone soil, where the mixture will partition and equilibrate with soil particles, pore vapor, and pore water. Complex organic mixtures can greatly complicate the determination and quantification of NAPL in soil due to inter-media transfer. NAPL thresholds can also change because of mixture physical properties and can disguise the presence of NAPL. A unique analytical method and copyrighted software have been developed at the Department of Energy's Savannah River Site that facilitates solution of this problem. The analytical method uses a classic chemistry approach and applies the principals of solubility limit theory, Raoult's Law, and equilibrium chemistry to derive an accurate estimation of NAPL presence and quantity. The method is unique because it calculates an exact result that is mass balanced for each physical state, chemical mixture component, and mixture characteristics. The method is also unique because the solution can be calculated on both a wet weight and dry weight basis--a factor which is often overlooked. The software includes physical parameters for 300 chemicals in a database that self-loads into the model to save time. The method accommodates up to 20 different chemicals in a multi-component mixture analysis. A robust data display is generated including important parameters of the components and mixture including: NAPL thresholds for individual chemical components within the mixture, mass distribution in soil for each physical state, molar fractions, density, vapor pressure, solubility, mass balance, media concentrations, residual saturation, and modest graphing capabilities. This method and software are power tools to simplify otherwise tedious

  5. Evaluation of environmental polychlorobiphenyls and DDE in terms of mixtures of commercial preparations from peak heights of packed-column gas chromatograms using a programmable calculator.

    PubMed

    Eder, G

    1976-06-23

    A method is proposed for evaluating gas chromatograms of multi-component PCB mixtures and superposed single components simultaneously. Apparent concentrations relative to a calibration mixture are assigned to a number of suitable peaks, and the apparent concentrations are related to the true concentrations by a set of linear equations, which are solved by least-squares approximation. The results are provided with an estimate of their confidence intervals.

  6. Microbial degradation of petroleum hydrocarbons.

    PubMed

    Varjani, Sunita J

    2017-01-01

    Petroleum hydrocarbon pollutants are recalcitrant compounds and are classified as priority pollutants. Cleaning up of these pollutants from environment is a real world problem. Bioremediation has become a major method employed in restoration of petroleum hydrocarbon polluted environments that makes use of natural microbial biodegradation activity. Petroleum hydrocarbons utilizing microorganisms are ubiquitously distributed in environment. They naturally biodegrade pollutants and thereby remove them from the environment. Removal of petroleum hydrocarbon pollutants from environment by applying oleophilic microorganisms (individual isolate/consortium of microorganisms) is ecofriendly and economic. Microbial biodegradation of petroleum hydrocarbon pollutants employs the enzyme catalytic activities of microorganisms to enhance the rate of pollutants degradation. This article provides an overview about bioremediation for petroleum hydrocarbon pollutants. It also includes explanation about hydrocarbon metabolism in microorganisms with a special focus on new insights obtained during past couple of years.

  7. Embryotoxic and teratogenic effects of petroleum hydrocarbons in mallards (Anas platyrhynchos)

    USGS Publications Warehouse

    Hoffman, D.J.

    1979-01-01

    Egg surface applications of microliter quantities of crude and refined oils of high aromatic content are embryotoxic to mallards (Anas platyrhynchos) and other avian species; applications of aliphatic hydrocarbons have virtually no effect. Mallard eggs at 72 h of development were exposed to a mixture of aromatic hydrocarbons or to aromatic compounds representative to those present in crude oil to assess their toxicity. The class composition of the mixture was similar to that of South Louisiana crude oil, an American Petroleum Institute reference oil. Application of 20 microliter of the mixture reduced embryonic survival by nearly 70%. The temporal pattern of embryonic death was similar to that after exposure to South Louisiana crude oil. Embryonic growth was stunted, as reflected by weight, crown-rump length, and bill length, and there was a significant increase in the incidence of abnormal survivors. When individual classes of aromatic hydrocarbons were tested, tetracyclics caused some embryonic death at the concentrations in the mixture. When classes were tested in all possible combinations of two, no combination appeared to be as toxic as the entire mixture. Addition of the tetracyclic compound chrysene to the aromatic mixture considerably enhanced embryotoxicity, but could not completely account for the toxicity of the crude oil. The presence of additional unidentified polycyclic aromatic hydrocarbons as well as methylated derivatives of polycyclic aromatic compounds such as chrysene may further account for the embryotoxicity of the crude oil.

  8. Embryotoxic and teratogenic effects of petroleum hydrocarbons in mallards (Anas platyrhynchos).

    PubMed

    Hoffman, D J

    1979-09-01

    Egg surface applications of microliter quantities of crude and refined oils of high aromatic content are embryotoxic to mallards (Anas platyrhynchos) and other avian species; applications of aliphatic hydrocarbons have virtually no effect. Mallard eggs at 72 h of development were exposed to a mixture of aromatic hydrocarbons or to aromatic compounds representative to those present in crude oil to assess their toxicity. The class composition of the mixture was similar to that of South Louisiana crude oil, an American Petroleum Institute reference oil. Application of 20 microliter of the mixture reduced embryonic survival by nearly 70%. The temporal pattern of embryonic death was similar to that after exposure to South Louisiana crude oil. Embryonic growth was stunted, as reflected by weight, crown-rump length, and bill length, and there was a significant increase in the incidence of abnormal survivors. When individual classes of aromatic hydrocarbons were tested, tetracyclics caused some embryonic death at the concentrations in the mixture. When classes were tested in all possible combinations of two, no combination appeared to be as toxic as the entire mixture. Addition of the tetracyclic compound chrysene to the aromatic mixture considerably enhanced embryotoxicity, but could not completely account for the toxicity of the crude oil. The presence of additional unidentified polycyclic aromatic hydrocarbons as well as methylated derivatives of polycyclic aromatic compounds such as chrysene may further account for the embryotoxicity of the crude oil.

  9. Method for producing hydrocarbon fuels from heavy polynuclear hydrocarbons by use of molten metal halide catalyst

    DOEpatents

    Gorin, Everett

    1979-01-01

    In a process for hydrocracking heavy polynuclear carbonaceous feedstocks to produce lighter hydrocarbon fuels by contacting the heavy feedstocks with hydrogen in the presence of a molten metal halide catalyst, thereafter separating at least a substantial portion of the carbonaceous material associated with the reaction mixture from the spent molten metal halide and thereafter regenerating the metal halide catalyst, an improvement comprising contacting the spent molten metal halide catalyst after removal of a major portion of the carbonaceous material therefrom with an additional quantity of hydrogen is disclosed.

  10. Origin of the hydrocarbon component of interplanetary dust particles

    NASA Technical Reports Server (NTRS)

    Wdowiak, Thomas J.; Lee, Wei

    1994-01-01

    Using experiments as a basis, we have developed a scenario for the origin of the hydrocarbon material of carbonaceous chondrites. This scenario can also serve as an explanation for the origin of the hydrocarbon component of interplanetary dust particles (IDP's). The formation of polycyclic aromatic hydrocarbon (PAH) molecules in the atmospheres of C stars undergoing a late stage of stellar evolution is indicated by the observed unidentified infrared (UIR) emission bands. Those molecules are then transported through interstellar space where they become enriched with D through ion molecule reactions when passing through cold, dark clouds. Many of those PAH molecules are subsequently hydrogenated and cracked in a H-dominated plasma such as would have occurred in the solar nebula. The resulting mixture of alkanes and residual D-rich PAH molecules was then incorporated into the mineral fraction of the parent bodies of carbonaceous chondrites and IDP's.

  11. A numerical study of laminar flames propagating in stratified mixtures

    NASA Astrophysics Data System (ADS)

    Zhang, Jiacheng

    (CTh) is shown to be a parameter that determines the effect of extra thermal diffusion by mixture stratification on flame propagation. Smaller values reflect less impact of stratification. For the cases considered, the values of CTh are quite small. This work suggests that employing the laminar flame speed from a homogeneous mixture to approximate the flame speed (and flame structure) in thermally and compositionally stratified mixtures is reasonable for hydrocarbon/air and hydrogen/air mixtures.

  12. Chemical reduction of biomass polysaccharides to liquid hydrocarbon fuels

    SciTech Connect

    Robinson, J.M.; Alaniz, N.J.; Beech, D.J.

    1996-12-31

    Biomass is fractionated into the principle components cellulose (1), hemicellulose (2), and lignin (3). The two polysaccharide fractions 1 & 2 are converted into polyols by catalytic hydrogenation. Sorbitol, resulting from 1 for example, is treated sequentially with a redox coupled mixture of hydriodic acid and phosphorous acid and then with alcoholic base to afford a mixture of hydrocarbons including hexene. Step 2 of the process is highly tunable and can directly produce about 80% hydrocarbon oligomers, C{sub 12}H{sub 22} and C{sub 18}H{sub 32} and only about 20% of the intermediate 2-iodohexane. Recent results in the development of this new process will be presented. Oxygenate fuel additives, hexanols and hexyl ethers are also available by further reactions of hexene. These are presented in the accompanying paper.

  13. Method for removing hydrocarbon contaminants from solid materials

    DOEpatents

    Bala, Gregory A.; Thomas, Charles P.

    1995-01-01

    A system for removing hydrocarbons from solid materials. Contaminated solids are combined with a solvent (preferably terpene based) to produce a mixture. The mixture is washed with water to generate a purified solid product (which is removed from the system) and a drainage product. The drainage product is separated into a first fraction (consisting mostly of contaminated solvent) and a second fraction (containing solids and water). The first fraction is separated into a third fraction (consisting mostly of contaminated solvent) and a fourth fraction (containing residual solids and water). The fourth fraction is combined with the second fraction to produce a sludge which is separated into a fifth fraction (containing water which is ultimately reused) and a sixth fraction (containing solids). The third fraction is then separated into a seventh fraction (consisting of recovered solvent which is ultimately reused) and an eighth fraction (containing hydrocarbon waste).

  14. Apparatus for removing hydrocarbon contaminants from solid materials

    DOEpatents

    Bala, Gregory A.; Thomas, Charles P.

    1996-01-01

    A system for removing hydrocarbons from solid materials. Contaminated solids are combined with a solvent (preferably terpene based) to produce a mixture. The mixture is washed with water to generate a purified solid product (which is removed from the system) and a drainage product. The drainage product is separated into a first fraction (consisting mostly of contaminated solvent) and a second fraction (containing solids and water). The first fraction is separated into a third fraction (consisting mostly of contaminated solvent) and a fourth fraction (containing residual solids and water). The fourth fraction is combined with the second fraction to produce a sludge which is separated into a fifth fraction (containing water which is ultimately reused) and a sixth fraction (containing solids). The third fraction is then separated into a seventh fraction (consisting of recovered solvent which is ultimately reused) and an eighth fraction (containing hydrocarbon waste).

  15. Apparatus for removing hydrocarbon contaminants from solid materials

    DOEpatents

    Bala, G.A.; Thomas, C.P.

    1996-02-13

    A system is described for removing hydrocarbons from solid materials. Contaminated solids are combined with a solvent (preferably terpene based) to produce a mixture. The mixture is washed with water to generate a purified solid product (which is removed from the system) and a drainage product. The drainage product is separated into a first fraction (consisting mostly of contaminated solvent) and a second fraction (containing solids and water). The first fraction is separated into a third fraction (consisting mostly of contaminated solvent) and a fourth fraction (containing residual solids and water). The fourth fraction is combined with the second fraction to produce a sludge which is separated into a fifth fraction (containing water which is ultimately reused) and a sixth fraction (containing solids). The third fraction is then separated into a seventh fraction (consisting of recovered solvent which is ultimately reused) and an eighth fraction (containing hydrocarbon waste). 4 figs.

  16. Method for removing hydrocarbon contaminants from solid materials

    DOEpatents

    Bala, G.A.; Thomas, C.P.

    1995-10-03

    A system is described for removing hydrocarbons from solid materials. Contaminated solids are combined with a solvent (preferably terpene based) to produce a mixture. The mixture is washed with water to generate a purified solid product (which is removed from the system) and a drainage product. The drainage product is separated into a first fraction (consisting mostly of contaminated solvent) and a second fraction (containing solids and water). The first fraction is separated into a third fraction (consisting mostly of contaminated solvent) and a fourth fraction (containing residual solids and water). The fourth fraction is combined with the second fraction to produce a sludge which is separated into a fifth fraction (containing water which is ultimately reused) and a sixth fraction (containing solids). The third fraction is then separated into a seventh fraction (consisting of recovered solvent which is ultimately reused) and an eighth fraction (containing hydrocarbon waste). 4 figs.

  17. Catalysts and process for liquid hydrocarbon fuel production

    DOEpatents

    White, Mark G; Liu, Shetian

    2014-12-09

    The present invention provides a novel process and system in which a mixture of carbon monoxide and hydrogen synthesis gas, or syngas, is converted into hydrocarbon mixtures composed of high quality gasoline components, aromatic compounds, and lower molecular weight gaseous olefins in one reactor or step. The invention utilizes a novel molybdenum-zeolite catalyst in high pressure hydrogen for conversion, as well as a novel rhenium-zeolite catalyst in place of the molybdenum-zeolite catalyst, and provides for use of the novel catalysts in the process and system of the invention.

  18. Transport equations for multicomponent anisotropic space plasmas - A review

    NASA Technical Reports Server (NTRS)

    Barakat, A. R.; Schunk, R. W.

    1982-01-01

    An attempt is made to present a unified approach to the study of transport phenomena in multicomponent anisotropic space plasmas. In particular, a system of generalized transport equations is presented that can be applied to widely different plasma flow conditions. The generalized transport equations can describe subsonic and supersonic flows, collision-dominated and collisionless flows, plasma flows in rapidly changing magnetic field configurations, multicomponent plasma flows with large temperature differences between the interacting species, and plasma flows that contain anisotropic temperature distributions. In addition, if Maxwell's equations of electricity and magnetism are added to the system of transport equations, they can be used to model electrostatic shocks, double layers, and magnetic merging processes. These transport equations also contain terms which act to regulate both the heat flow and temperature anisotropy, processes which appear to be operating in the solar wind.

  19. Electrostatic twisted modes in multi-component dusty plasmas

    SciTech Connect

    Ayub, M. K.; Ali, S.; Ikram, M.

    2016-01-15

    Various electrostatic twisted modes are re-investigated with finite orbital angular momentum in an unmagnetized collisionless multi-component dusty plasma, consisting of positive/negative charged dust particles, ions, and electrons. For this purpose, hydrodynamical equations are employed to obtain paraxial equations in terms of density perturbations, while assuming the Gaussian and Laguerre-Gaussian (LG) beam solutions. Specifically, approximated solutions for potential problem are studied by using the paraxial approximation and expressed the electric field components in terms of LG functions. The energy fluxes associated with these modes are computed and corresponding expressions for orbital angular momenta are derived. Numerical analyses reveal that radial/angular mode numbers as well as dust number density and dust charging states strongly modify the LG potential profiles attributed to different electrostatic modes. Our results are important for understanding particle transport and energy transfer due to wave excitations in multi-component dusty plasmas.

  20. Efficient Ab initio Modeling of Random Multicomponent Alloys.

    PubMed

    Jiang, Chao; Uberuaga, Blas P

    2016-03-11

    We present in this Letter a novel small set of ordered structures (SSOS) method that allows extremely efficient ab initio modeling of random multicomponent alloys. Using inverse II-III spinel oxides and equiatomic quinary bcc (so-called high entropy) alloys as examples, we demonstrate that a SSOS can achieve the same accuracy as a large supercell or a well-converged cluster expansion, but with significantly reduced computational cost. In particular, because of this efficiency, a large number of quinary alloy compositions can be quickly screened, leading to the identification of several new possible high-entropy alloy chemistries. The SSOS method developed here can be broadly useful for the rapid computational design of multicomponent materials, especially those with a large number of alloying elements, a challenging problem for other approaches.

  1. High Glass Transition Temperature Renewable Polymers via Biginelli Multicomponent Polymerization.

    PubMed

    Boukis, Andreas C; Llevot, Audrey; Meier, Michael A R

    2016-04-01

    A novel and straightforward one-pot multicomponent polycondensation method was established in this work. The Biginelli reaction is a versatile multicomponent reaction of an aldehyde, a β-ketoester (acetoacetate) and urea, which can all be obtained from renewable resources, yielding diversely substituted 3,4-dihydropyrimidin-2(1H)-ones (DHMPs). In this study, renewable diacetoacetate monomers with different spacer chain lengths (C3, C6, C10, C20) were prepared via simple transesterification of renewable diols and commercial acetoacetates. The diacetoacetate monomers were then reacted with renewable dialdehydes, i.e., terephthalaldehyde and divanillin in a Biginelli type step-growth polymerization. The obtained DHMP polymers (polyDHMPs) displayed high molar masses, high glass transition temperatures (Tg) up to 203 °C and good thermal stability (Td5%) of 280 °C. The Tg of the polyDHMPs could be tuned by variation of the structure of the dialdehyde or the diacetoacetate component.

  2. Multicomponent delirium prevention: not as effective as NICE suggest?

    PubMed

    Teale, Elizabeth; Young, John

    2015-11-01

    Multicomponent delirium prevention strategies have been shown in intervention studies consistently to reduce the occurrence of delirium. Based on this convincing evidence base, the National Institute for Health and Care Excellence has advocated the widespread adoption of multicomponent delirium prevention interventions into the routine inpatient care of older people. However, despite successful reductions in incident delirium of about a third, anticipated reductions in mortality or admissions to long-term care--both clinically important endpoints statistically correlated with the occurrence of delirium--have not been conclusively observed. We hypothesise that the reasons for this disconnection are partly methodological, due to difficulties in delirium detection and blinding of study personnel to the intervention, but predominantly due to the underlying relationship between delirium and the abnormal health state of frailty; the interaction between these two geriatric syndromes is currently poorly understood.

  3. Thin multicomponent films for functional enzyme devices and bioreactor particles

    PubMed Central

    Rusling, James F.; Wasalathanthri, Dhanuka P.; Schenkman, John B.

    2014-01-01

    Complex functional films containing enzymes and other biomolecules are easily fabricated in nm-scale thicknesses by using layer-by-layer (LbL) methodologies first popularized by Lvov and Decher. In this review, we highlight the high level functional capabilities possible with LbL films of biomolecules based on our own research experiences. We first describe the basics of enzyme film fabrication by LbL alternate electrostatic adsorption, then discuss how to make functional enzyme-polyion films of remarkably high stability. Focusing on cytochrome P450s, we discuss films developed to electrochemically activate the natural catalytic cycle of these key metabolic enzymes. We then describe multifunctional, multicomponent DNA/enzyme/polyion films on arrays and particle surfaces for high throughput metabolic toxicity screening using electrochemiluminescence and LC-MS/MS. Using multicomponent LbL films, complex functionality for bioanalytical and biochemical purposes can be achieved that is difficult or impossible using conventional approaches. PMID:25209428

  4. Physical aspects of heterogeneities in multi-component lipid membranes.

    PubMed

    Komura, Shigeyuki; Andelman, David

    2014-06-01

    Ever since the raft model for biomembranes has been proposed, the traditional view of biomembranes based on the fluid-mosaic model has been altered. In the raft model, dynamical heterogeneities in multi-component lipid bilayers play an essential role. Focusing on the lateral phase separation of biomembranes and vesicles, we review some of the most relevant research conducted over the last decade. We mainly refer to those experimental works that are based on physical chemistry approach, and to theoretical explanations given in terms of soft matter physics. In the first part, we describe the phase behavior and the conformation of multi-component lipid bilayers. After formulating the hydrodynamics of fluid membranes in the presence of the surrounding solvent, we discuss the domain growth-law and decay rate of concentration fluctuations. Finally, we review several attempts to describe membrane rafts as two-dimensional microemulsion.

  5. Bidirectional macrocyclization of peptides by double multicomponent reactions.

    PubMed

    Ricardo, Manuel G; Morales, Fidel E; Garay, Hilda; Reyes, Osvaldo; Vasilev, Dimitar; Wessjohann, Ludger A; Rivera, Daniel G

    2015-01-14

    Increasing the diversity of peptide cyclization methods is an effective way of accessing new types of macrocyclic chemotypes featuring a wide variety of ring sizes and topologies. Multicomponent reactions (MCRs) are processes capable of generating great levels of molecular diversity and complexity at low synthetic cost. In an attempt to further exploit MCRs in the field of cyclopeptides, we describe a bidirectional multicomponent approach for the synthesis of N-alkylated macrocyclic peptides of varied sequences and cross-linking positions. The process relies on the execution of two Ugi reactions between peptide diacids and diisocyanides. Varying the amino component enabled the installation of exocyclic elements of diversity, while skeletal diversity was created through different side chain and backbone cyclizations. This procedure shows prospects for the rapid scanning of the chemical space of macrocyclic peptides for applications in chemical biology and drug discovery.

  6. Method for producing nanocrystalline multicomponent and multiphase materials

    DOEpatents

    Eastman, J.A.; Rittner, M.N.; Youngdahl, C.J.; Weertman, J.R.

    1998-03-17

    A process for producing multi-component and multiphase nanophase materials is provided wherein a plurality of elements are vaporized in a controlled atmosphere, so as to facilitate thorough mixing, and then condensing and consolidating the elements. The invention also provides for a multicomponent and multiphase nanocrystalline material of specified elemental and phase composition having component grain sizes of between approximately 1 nm and 100 nm. This material is a single element in combination with a binary compound. In more specific embodiments, the single element in this material can be a transition metal element, a non-transition metal element, a semiconductor, or a semi-metal, and the binary compound in this material can be an intermetallic, an oxide, a nitride, a hydride, a chloride, or other compound. 6 figs.

  7. Method for producing nanocrystalline multicomponent and multiphase materials

    DOEpatents

    Eastman, Jeffrey A.; Rittner, Mindy N.; Youngdahl, Carl J.; Weertman, Julia R.

    1998-01-01

    A process for producing multi-component and multiphase nanophase materials is provided wherein a plurality of elements are vaporized in a controlled atmosphere, so as to facilitate thorough mixing, and then condensing and consolidating the elements. The invention also provides for a multicomponent and multiphase nanocrystalline material of specified elemental and phase composition having component grain sizes of between approximately 1 nm and 100 nm. This material is a single element in combination with a binary compound. In more specific embodiments, the single element in this material can be a transition metal element, a non-transition metal element, a semiconductor, or a semi-metal, and the binary compound in this material can be an intermetallic, an oxide, a nitride, a hydride, a chloride, or other compound.

  8. Hydrodynamic model for expansion and collisional relaxation of x-ray laser-excited multi-component nanoplasma

    SciTech Connect

    Saxena, Vikrant; Ziaja, Beata

    2016-01-15

    The irradiation of an atomic cluster with a femtosecond x-ray free-electron laser pulse results in a nanoplasma formation. This typically occurs within a few hundred femtoseconds. By this time the x-ray pulse is over, and the direct photoinduced processes no longer contributing. All created electrons within the nanoplasma are thermalized. The nanoplasma thus formed is a mixture of atoms, electrons, and ions of various charges. While expanding, it is undergoing electron impact ionization and three-body recombination. Below we present a hydrodynamic model to describe the dynamics of such multi-component nanoplasmas. The model equations are derived by taking the moments of the corresponding Boltzmann kinetic equations. We include the equations obtained, together with the source terms due to electron impact ionization and three-body recombination, in our hydrodynamic solver. Model predictions for a test case, expanding spherical Ar nanoplasma, are obtained. With this model, we complete the two-step approach to simulate x-ray created nanoplasmas, enabling computationally efficient simulations of their picosecond dynamics. Moreover, the hydrodynamic framework including collisional processes can be easily extended for other source terms and then applied to follow relaxation of any finite non-isothermal multi-component nanoplasma with its components relaxed into local thermodynamic equilibrium.

  9. High-performance thin layer chromatography for quality control of multicomponent herbal drugs: example of cangzhu xianglian san.

    PubMed

    Li, Zhi; Merfort, Irmgard; Reich, Eike

    2010-01-01

    Due to their complexity, multicomponent herbal drugs pose enormous analytical challenges for quality control (QC). Although they may have traditionally been used for hundreds of years, the information about their chemical composition is often still limited. Selecting suitable markers to monitor the identity and potency of the mixture is, therefore, difficult. There is also the possibility of natural variability for each plant. This paper illustrates a pragmatic and practical approach to QC of a multicomponent herbal drug by HPTLC. Cangzhu xianglian xan (CXS), composed of the herbal drugs Coptis rhizome, Aucklandia root, and Atractylodes rhizome (30 + 20 + 60, w/w/w), is used as an example. A characteristic fingerprint can be generated for CXS with toluene-ethyl acetate-methanol-isopropanol-water (60 + 30 + 20 + 15 + 3, v/v/v/v/v) mobile phase on HPTLC silica gel 60 conditioned with ammonia. While the corresponding monograph of the Chinese Veterinary Pharmacopoeia focuses only on the detection of berberine, one of the principal components of Coptis rhizome, the proposed method of identification determines the presence of all three components in the drug after derivatization with anisaldehyde reagent. The same method can also be used to quantitatively determine the content of berberine by scanning densitometry. This paper provides details about the validation of the qualitative and quantitative determinations.

  10. Symmetric normal mixtures

    NASA Technical Reports Server (NTRS)

    Turmon, Michael

    2004-01-01

    We consider mixture density estimation under the symmetry constraint x = Az for an orthogonal matrix A. This distributional constraint implies a corresponding constraint on the mixture parameters. Focusing on the gaussian case, we derive an expectation-maximization (EM) algorithm to enforce the constraint and show results for modeling of image feature vectors.

  11. Numerical study of multicomponent droplet vaporization at near critical conditions

    NASA Technical Reports Server (NTRS)

    Hsieh, Kwang-Chung; Shuen, Jian-Shun; Yang, Vigor

    1988-01-01

    A comprehensive numerical analysis of multicomponent droplet vaporization at near critical conditions has been carried out. The model is based on the full time-dependent conservation equations and accommodates various important high-pressure phenomena. As an example, the case involving a two-component (n-pentane and n-octane) fuel droplet in nitrogen gas is studied. The influences of transient effects, surface regression, ambient gas solubility, and phase-equilibrium relations on vaporization mechanisms are examined in detail.

  12. Multicomponent fiber optical biosensor for use in hemodialysis monitoring

    NASA Astrophysics Data System (ADS)

    Mueller, Cord; Schubert, Florian; Scheper, Thomas

    1994-07-01

    In clinical chemistry, sensors are needed that can detect small analyte concentrations in complex physiological media. During hemodialysis it is especially important to determine the urea concentration on line in order to monitor the completion of the purification. In this paper we describe a multicomponent fiberoptical biosensor for use in hemodialysis monitoring. Since no substrate flow is required in the sensor head, this technology is especially suited for monitoring in physiological solutions (no electrical contact to the patient is necessary).

  13. Ab initio calculations for search optimization of multicomponent alloy configurations

    NASA Astrophysics Data System (ADS)

    Nikonov, A. Yu.; Zharmukhambetova, A. M.; Dmitriev, A. I.

    2016-11-01

    The paper presents an algorithm for optimization of searching configurations of multicomponent alloys that have a predetermined value of physical and mechanical properties. Values obtained by Exact MT Orbitals (EMTO) were used for calculations. The algorithm efficiency is demonstrated on an example of estimating the bulk modulus of a three-component alloy based on Ti, Nb and Zr. It is shown that the use of the algorithm can in some cases reduce the amount of calculations by 10 times or more.

  14. Gauge-invariant perturbations in multi-component fluid cosmologies.

    NASA Astrophysics Data System (ADS)

    Dunsby, P. K. S.

    A new covariant formalism was introduced to describe the evolution of inhomogeneities in any spacetime. The variables introduced in these papers are gauge-invariant with respect to a Robertson-Walker background spacetime because they vanish identically in such models and have a transparent physical and geometrical meaning. The author briefly discusses how to extend this formalism to systems of multi-component fluids and sketches how the variables are related to those of Bardeen.

  15. Generalized statistical model for multicomponent adsorption equilibria on zeolites

    SciTech Connect

    Rota, R.; Gamba, G.; Paludetto, R.; Carra, S.; Morbidelli, M. )

    1988-05-01

    The statistical thermodynamic approach to multicomponent adsorption equilibria on zeolites has been extended to nonideal systems, through the correction of cross coefficients characterizing the interaction between unlike molecules. Estimation of the model parameters requires experimental binary equilibrium data. Comparisons with the classical model based on adsorbed solution theory are reported for three nonideal ternary systems. The two approaches provide comparable results in the simulation of binary and ternary adsorption equilibrium data at constant temperature and pressure.

  16. Hydrocarbon bioremediation -- An overview

    SciTech Connect

    Reisinger, H.J.

    1995-12-31

    Bioremediation is the process that transforms xenobiotics introduced into the environment to a less toxic or innocuous form, or mineralizes them to inorganic species. The processes can be carried out through either aerobic or anaerobic pathways by indigenous heterotrophs or by specially engineered organisms. For some xenobiotics, the process can also be carried out by cometabolic processes, which use another compound as the carbon and energy source. This technique can be applied either in situ or ex situ. An overview is presented of real-world applications of a variety of hydrocarbon bioremediation approaches, including biopiling, bioventing, bioslurping, landfarming, electrobioreclamation, and biovertical circulation wells. Problems in translating laboratory and field-scale pilot test data to full-scale operating systems are discussed. Such issues include biodegradation enhancement, nutrient and electron acceptor delivery, alternative electron acceptors, and integration of biological, chemical, and physical approaches to hydrocarbon remediation.

  17. Near azeotropic mixture substitute

    NASA Technical Reports Server (NTRS)

    Jones, Jack A. (Inventor)

    1996-01-01

    The present invention comprises a refrigerant mixture consisting of a first mole fraction of 1,1,1,2-tetrafluoroethane (R134a) and a second mole fraction of a component selected from the group consisting of a mixture of CHClFCF.sub.3 (R124) and CH.sub.3 CClF.sub.2 (R142b); a mixture of CHF.sub.2 CH.sub.3 (R152a) and CHClFCF.sub.3 (R124); a mixture of CHF.sub.2 CH.sub.3 (R152a) and CH.sub.3 CClF.sub.2 (R142b); and a mixture of CHClFCF.sub.3 (R124), CH.sub.3 CClF.sub.2 (R142b) and CHF.sub.2 CH.sub.3 (R152a).

  18. Direct hydrocarbon fuel cells

    DOEpatents

    Barnett, Scott A.; Lai, Tammy; Liu, Jiang

    2010-05-04

    The direct electrochemical oxidation of hydrocarbons in solid oxide fuel cells, to generate greater power densities at lower temperatures without carbon deposition. The performance obtained is comparable to that of fuel cells used for hydrogen, and is achieved by using novel anode composites at low operating temperatures. Such solid oxide fuel cells, regardless of fuel source or operation, can be configured advantageously using the structural geometries of this invention.

  19. Dynamic simulation of multicomponent reaction transport in water distribution systems.

    PubMed

    Munavalli, G R; Mohan Kumar, M S M S

    2004-04-01

    Given the presence of nutrients, regrowth of bacteria within a distribution system is possible. The bacterial growth phenomena, which can be studied by developing a multicomponent (substrate, biomass and disinfectant) reaction transport model, is governed by its relationship with the substrate (organic carbon) and disinfectant (chlorine). The multicomponent reaction transport model developed in the present study utilizes the simplified expressions for the basic processes (in bulk flow and at pipe wall) such as bacterial growth and decay, attachment to and detachment from the surface, substrate utilization and disinfectant action involved in the model. The usefulness of the model is further enhanced by the incorporation of an expression for bulk reaction parameter relating it with the organic carbon. The model is validated and applied to study the sensitive behavior of the components using a hypothetical network. The developed model is able to simulate the biodegradable organic carbon threshold in accordance with the values reported in the literature. The spread of contaminant intruded into the system at any location can also be simulated by the model. The multicomponent model developed is useful for water supply authorities in identifying the locations with high substrate concentrations, bacterial growth and lower chlorine residuals.

  20. Hydrodynamic theory of diffusion in two-temperature multicomponent plasmas

    SciTech Connect

    Ramshaw, J.D.; Chang, C.H.

    1995-12-31

    Detailed numerical simulations of multicomponent plasmas require tractable expressions for species diffusion fluxes, which must be consistent with the given plasma current density J{sub q} to preserve local charge neutrality. The common situation in which J{sub q} = 0 is referred to as ambipolar diffusion. The use of formal kinetic theory in this context leads to results of formidable complexity. We derive simple tractable approximations for the diffusion fluxes in two-temperature multicomponent plasmas by means of a generalization of the hydrodynamical approach used by Maxwell, Stefan, Furry, and Williams. The resulting diffusion fluxes obey generalized Stefan-Maxwell equations that contain driving forces corresponding to ordinary, forced, pressure, and thermal diffusion. The ordinary diffusion fluxes are driven by gradients in pressure fractions rather than mole fractions. Simplifications due to the small electron mass are systematically exploited and lead to a general expression for the ambipolar electric field in the limit of infinite electrical conductivity. We present a self-consistent effective binary diffusion approximation for the diffusion fluxes. This approximation is well suited to numerical implementation and is currently in use in our LAVA computer code for simulating multicomponent thermal plasmas. Applications to date include a successful simulation of demixing effects in an argon-helium plasma jet, for which selected computational results are presented. Generalizations of the diffusion theory to finite electrical conductivity and nonzero magnetic field are currently in progress.