WorldWideScience

Sample records for involving nonideal mixtures

  1. Relaxation in binary mixtures: Non-ideality, heterogeneity and re ...

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Chemical Sciences; Volume 113; Issue 5-6. Relaxation in ... Binary mixtures show many kinds of fascinating dynamical behaviour which has eluded microscopic description till very recently. In this work we show ... Specifically, three well-known problems have been addressed here. Non-ideality in ...

  2. Kelvin Equation for a Non-Ideal Multicomponent Mixture

    DEFF Research Database (Denmark)

    Shapiro, Alexander; Stenby, Erling Halfdan

    1997-01-01

    The Kelvin equation is generalized by application to a case of a multicomponent non-ideal mixture. Such a generalization is necessary in order to describe the two-phase equilibrium in a capillary medium with respect to both normal and retrograde condensation. The equation obtained is applied...

  3. Composition dependent non-ideality in aqueous binary mixtures as ...

    Indian Academy of Sciences (India)

    Abstract. We explore the potential energy landscape of structure breaking binary mixtures (SBBM) where two constituents dislike each other, yet remain macroscopically homogeneous at intermediate to high temper- atures. Interestingly, we find that the origin of strong composition dependent non-ideal behaviour lies in its.

  4. Chemical structure influence on NAPL mixture nonideality evolution, rate-limited dissolution, and contaminant mass flux

    Science.gov (United States)

    Padgett, Mark C.; Tick, Geoffrey R.; Carroll, Kenneth C.; Burke, William R.

    2017-03-01

    The influence of chemical structure on NAPL mixture nonideality evolution, rate-limited dissolution, and contaminant mass flux was examined. The variability of measured and UNIFAC modeled NAPL activity coefficients as a function of mole fraction was compared for two NAPL mixtures containing structurally-different contaminants of concern including toluene (TOL) or trichloroethene (TCE) within a hexadecane (HEXDEC) matrix. The results showed that dissolution from the NAPL mixtures transitioned from ideality for mole fractions > 0.05 to nonideality as mole fractions decreased. In particular, the TCE generally exhibited more ideal dissolution behavior except at lower mole fractions, and may indicate greater structural/polarity similarity between the two compounds. Raoult's Law and UNIFAC generally under-predicted the batch experiment results for TOL:HEXDEC mixtures especially for mole fractions ≤ 0.05. The dissolution rate coefficients were similar for both TOL and TCE over all mole fractions tested. Mass flux reduction (MFR) analysis showed that more efficient removal behavior occurred for TOL and TCE with larger mole fractions compared to the lower initial mole fraction mixtures (i.e. < 0.2). However, compared to TOL, TCE generally exhibited more efficient removal behavior over all mole fractions tested and may have been the result of structural and molecular property differences between the compounds. Activity coefficient variability as a function of mole fraction was quantified through regression analysis and incorporated into dissolution modeling analyses for the dynamic flushing experiments. TOL elution concentrations were modeled (predicted) reasonable well using ideal and equilibrium assumptions, but the TCE elution concentrations could not be predicted using the ideal model. Rather, the dissolution modeling demonstrated that TCE elution was better described by the nonideal model whereby NAPL-phase activity coefficient varied as a function of COC mole

  5. Surface Tension of Nonideal Binary Liquid Mixtures as a Function of Composition.

    Science.gov (United States)

    Nath

    1999-01-01

    The composition dependence of the surface tension of highly nonideal organic-organic and aqueous-organic nonelectrolyte solutions is described, based on the assumption that the surface layer can be treated as a separate phase located between vapor and bulk liquid phases. The Wilson, NRTL, and UNIFAC methods are used for activity coefficients of surface and bulk phases and three techniques for calculation of molar surface areas, based on Paquette areas, Rasmussen areas, and a Langmuir-type approach are tested. Comparisons of the calculated surface tensions with experimental data yield mean absolute errors, in the best case, of less than 2.5% for the systems studied, all of which exhibit highly nonideal behavior. The surface tension predictions are found to be extremely sensitive to the values of the molar surface areas used in the computation. A Langmuir-type adsorption model is formulated to determine the surface mole fractions from a knowledge of the mixture surface tension as a function of bulk composition. A novel procedure is developed to obtain the partial molar surface area of the larger organic component as a function of composition in binary aqueous-organic systems, assuming that the two components are very dissimilar in size, and that deviations in the partial molar surface area of the smaller component (water) from its pure component molar surface area contribute negligibly to the total molar surface area of the mixture. This removes the approximation of equality of partial and pure component molar surface area for the larger organic component. Use of the Langmuir-type approach with partial molar surface areas improves surface tension predictions of highly nonideal aqueous-organic mixtures by 20% over use of pure component molar surface areas. It is an important first step in the development of a thermodynamically consistent theory of surfaces for liquid mixtures based on an accurate determination of the composition dependence of partial molar surface

  6. Nonideal equilibrium dissolution of trichloroethene from a decane-based nonaqueous phase liquid mixture: Experimental and modeling investigation

    Science.gov (United States)

    McCray, John E.; Dugan, Pamela J.

    2002-07-01

    Batch equilibrium solubility studies were conducted to examine the solubilization behavior of a chlorinated solvent, trichloroethene (TCE), from a fuel-based nonaqueous phase liquid (NAPL) mixture. An alkane (n-decane) was used as a model compound because it is often a primary compound in jet fuel. The NAPL phase mole fractions of the chlorinated solvent in the mixture (XTCEN) that were investigated are typical of in situ values found at industrial and military waste sites (0.0001 >= XTCEN UNIFAC method greatly underpredicts the γTCEN in this surrogate fuel. A NAPL-mixture equilibrium-dissolution model was developed that incorporates the observed nonideal dissolution. This model indicates that nonideal NAPL dissolution is 4 times faster than ideal dissolution for a hypothetical NAPL mixture with an initial XTCEN = 0.001. The magnitude of this effect becomes more important as the initial value of the XTCEN is decreased.

  7. Propagation of a spherical shock wave in mixture of non-ideal gas and small solid particles under gravitational field with conductive and radiative heat fluxes

    Science.gov (United States)

    Nath, Gorakh

    Self-similar solutions are obtained for one-dimensional unsteady adiabatic flow behind a spherical shock wave propagating in a dusty gas with conductive and radiative heat fluxes under a gravitational field. The shock is assumed to be driven out by a moving piston and the dusty gas to be a mixture of non-ideal (or perfect) gas and small solid particles, in which solid particles are continuously distributed. It is assumed that the equilibrium flow-conditions are maintained and variable energy input is continuously supplied by the piston. The heat conduction is express in terms of Fourier’s law and the radiation is considered to be of the diffusion type for an optically thick grey gas model. The thermal conductivity and the absorption coefficient are assumed to vary with temperature and density. The medium is assumed to be under a gravitational field due to heavy nucleus at the origin (Roche Model). The unsteady model of Roche consists of a dusty gas distributed with spherical symmetry around a nucleus having large mass It is assumed that the gravitational effect of the mixture itself can be neglected compared with the attraction of the heavy nucleus. The density of the ambient medium is taken to be constant. Our analysis reveals that after inclusion of gravitational field effect surprisingly the shock strength increases and remarkable difference can be found in the distribution of flow variables. The effects of the variation of the heat transfer parameters, the gravitational parameter and non-idealness of the gas in the mixture are investigated. Also, the effects of an increase in (i) the mass concentration of solid particles in the mixture and (ii) the ratio of the density of solid particles to the initial density of the gas on the flow variables are investigated. It is found that the shock strength is increased with an increase in the value of gravitational parameter. Further, it is investigated that the presence of gravitational field increases the

  8. A non-ideal model for predicting the effect of dissolved salt on the flash point of solvent mixtures.

    Science.gov (United States)

    Liaw, Horng-Jang; Wang, Tzu-Ai

    2007-03-06

    Flash point is one of the major quantities used to characterize the fire and explosion hazard of liquids. Herein, a liquid with dissolved salt is presented in a salt-distillation process for separating close-boiling or azeotropic systems. The addition of salts to a liquid may reduce fire and explosion hazard. In this study, we have modified a previously proposed model for predicting the flash point of miscible mixtures to extend its application to solvent/salt mixtures. This modified model was verified by comparison with the experimental data for organic solvent/salt and aqueous-organic solvent/salt mixtures to confirm its efficacy in terms of prediction of the flash points of these mixtures. The experimental results confirm marked increases in liquid flash point increment with addition of inorganic salts relative to supplementation with equivalent quantities of water. Based on this evidence, it appears reasonable to suggest potential application for the model in assessment of the fire and explosion hazard for solvent/salt mixtures and, further, that addition of inorganic salts may prove useful for hazard reduction in flammable liquids.

  9. Ideal and non-ideal behaviour of {1-butyl-1-methylpyrrolydinium bis(trifluoromethylsulfonyl)imide + γ-butyrolactone} binary mixtures

    International Nuclear Information System (INIS)

    Vraneš, Milan; Tot, Aleksandar; Papović, Snežana; Zec, Nebojša; Dožić, Sanja; Gadžurić, Slobodan

    2015-01-01

    Graphical abstract: - Highlights: • Excess properties of ([bmpyrr][NTf 2 ] + γ-butyrolactone) mixtures are reported. • An ideal behaviour of the mixture was observed. • Interactions in the mixtures are weaker comparing to pure IL and GBL. • Calculated Angell’s strength parameter indicates a “fragile” ionic liquid. • [bmpyrr] + forms micellar structures when x IL > 0.6. - Abstract: Density, electrical conductivity and viscosity of binary liquid mixtures of 1-butyl-1-methylpyrrolydinium bis(trifluoromethylsulfonyl)imide, [bmpyrr][NTf 2 ], with γ-butyrolactone (GBL) were measured at temperatures from (293.15 to 323.15) K and at atmospheric pressure over the whole composition range. Excess molar volumes have been calculated from the experimental densities and fitted with the Redlich–Kister polynomial equation. These values are positive over the whole range of ionic liquid mole fraction and at all temperatures. In the range between 0.55 and 0.6 [bmpyrr][NTf 2 ] mole fraction, an ideal behaviour of the ionic liquid mixture with molecular solvent was observed for the first time. Other volumetric properties, such as isobaric thermal expansion coefficients, partial molar volumes and partial molar volumes at infinite dilution have been also calculated, in order to obtain information about interactions between GBL and selected ionic liquid. Positive values of these properties for both components also indicate weaker interactions between GBL and IL compared to the pure components. From the viscosity results, the Angell strength parameter was calculated and found to be 3.24 indicating that [bmpyrr][NTf 2 ] is a “fragile” liquid. From the volumetric and transport properties obtained, formation of the [bmpyrr] + micellar structures was also discussed. All the results are compared to those obtained for imidazolium-based ionic liquid with GBL

  10. Propagation of a spherical shock wave in mixture of non-ideal gas and small solid particles under the influence of gravitational field with conductive and radiative heat fluxes

    Science.gov (United States)

    Nath, G.

    2016-01-01

    Self-similar solutions are obtained for one-dimensional unsteady adiabatic flow behind a spherical shock wave propagating in a dusty gas with conductive and radiative heat fluxes under the influence of a gravitational field. The shock is assumed to be driven out by a moving piston and the dusty gas to be a mixture of non-ideal gas and small solid particles, in which solid particles are uniformly distributed. It is assumed that the equilibrium flow-conditions are maintained and variable energy input is continuously supplied by the piston. The heat conduction is expressed in terms of Fourier's law and the radiation is considered to be of the diffusion type for an optically thick grey gas model. The thermal conductivity K and the absorption coefficient αR are assumed to vary with temperature and density. The medium is assumed to be under the influence of a gravitational field due to central mass ( bar{m} ) at the origin (Roche Model). It is assumed that the gravitational effect of the mixture itself can be neglected compared with the attraction of the central mass. The initial density of the ambient medium is taken to be always constant. The effects of the variation of the gravitational parameter and nonidealness of the gas in the mixture are investigated. Also, the effects of an increase in (i) the mass concentration of solid particles in the mixture and (ii) the ratio of the density of solid particles to the initial density of the gas on the flow variables are investigated. It is shown that due to an increase in the gravitational parameter the compressibility of the medium at any point in the flow-field behind the shock decreases and all other flow variables and the shock strength are increased. Further, it is found that the presence of gravitational field increases the compressibility of the medium, due to which it is compressed and therefore the distance between the piston and the shock surface is reduced. The shock waves in dusty gas under the influence of a

  11. Kinetic theory of nonideal gases and nonideal plasmas

    CERN Document Server

    Klimontovich, Yu L

    2013-01-01

    Kinetic Theory of Nonideal Gases and Nonideal Plasmas presents the fundamental aspects of the kinetic theory of gases and plasmas. The book consists of three parts, which attempts to present some of the ideas, methods and applications in the study of the kinetic processes in nonideal gases and plasmas. The first part focuses on the classical kinetic theory of nonideal gases. The second part discusses the classical kinetic theory of fully ionized plasmas. The last part is devoted to the quantum kinetic theory of nonideal gases and plasmas. A concluding chapter is included, which presents a shor

  12. Study of a non-ideal liquid mixture in the hydrodynamic regime. Rayleigh-Brillouin spectra, sound propagation and damping in the CH3CN-CCl4 system at the azeotropic composition

    International Nuclear Information System (INIS)

    Sassi, Paola; D'Elia, Valerio; Cataliotti, Rosario Sergio

    2003-01-01

    The hydrodynamic behaviour in the GHz frequency region has been analzsed for the non-ideal CH 3 CN-CCl 4 liquid mixture around the azeotropic composition. Rayleigh-Brillouin spectra have been measured as a function of temperature and composition, at fixed value of transferred wave vector in the 90 deg. scattering geometry, and also at different scattering angles to study dispersion with frequency of the spectral observables. These measurements have been complemented by those of refractive index, density and viscosity at the same temperatures and mole fraction values. Very interesting behaviour of the classic Brillouin spectral observables, such as the hypersonic propagation speeds and the acoustic absorption coefficients, has been revealed near the azeotropic composition of the mixture at the investigated temperatures, namely 15 deg. C, 25 deg. C, 40 deg. C and 60 deg. C. These effects have been interpreted at the light of the Mountain and Deutch theory of binary solutions and the forecast behaviour of the intermolecular forces around the azeotropic point composition of these very different molecular liquids

  13. Non-Ideal Behavior in Solvent Extraction

    Energy Technology Data Exchange (ETDEWEB)

    Peter Zalupski

    2011-09-01

    This report presents a summary of the work performed to meet FCR&D level 3 milestone M31SW050801, 'Complete the year-end report summarizing FY11 experimental and modeling activities.' This work was carried out under the auspices of the Non-Ideality in Solvent Extraction Systems FCR&D work package. The report summarizes our initial considerations of potential influences that non-ideal chemistry may impose on computational prediction of outcomes in solvent extraction systems. The report is packaged into three separate test cases where a robustness of the prediction by SXFIT program is under scrutiny. The computational exercises presented here emphasize the importance of accurate representation of both an aqueous and organic mixtures when modeling liquid-liquid distribution systems. Case No.1 demonstrates that non-ideal behavior of HDEHP in aliphatic diluents, such as n-dodecane, interferes with the computation. Cases No.2 and No.3 focus on the chemical complexity of aqueous electrolyte mixtures. Both exercises stress the need for an improved thermodynamic model of an aqueous environment present in the europium distribution experiments. Our efforts for year 2 of this project will focus on the improvements of aqueous and non-aqueous solution models using fundamental physical properties of mixtures acquired experimentally in our laboratories.

  14. The non-ideal behaviour of the interfacial tension of the n-heptane + perfluoro-n-hexane mixture: A computational study

    Science.gov (United States)

    Dominguez, Hector

    2015-05-01

    Computer simulations of the n-heptane + perfluoro-n-hexane system is used to understand the unusual behaviour of the horizontal inflection of the vapour-liquid interfacial tension experiments of alkanes-perfluoroalkanes mixtures. Simulations are conducted and good agreement with experiments is obtained. From the results a change in curvature to a nearly constant value in the tensions at high perfluoro-n-hexane compositions is identified. Dynamic, thermodynamic and structural properties are analysed in that region and peculiar tendencies of those properties are found which help us to understand the nature of the uncommon inflection in the isotherms.

  15. Graham's law of diffusion: Quantum analogy and non-ideality

    Indian Academy of Sciences (India)

    We focus attention on two equivalent forms of Graham's law of diffusion that is valid for an ideal gas mixture. This equivalence is shown to be lost by the empirical equations of state in presence of an attractive nonideality. The modified forms are noted. We then construct a simple quantum mechanical model to simulate these ...

  16. Graham's law of diffusion: Quantum analogy and non-ideality

    Indian Academy of Sciences (India)

    Administrator

    Abstract. We focus attention on two equivalent forms of Graham's law of diffusion that is valid for an ideal gas mixture. This equivalence is shown to be lost by the empirical equations of state in presence of an attractive nonideality. The modified forms are noted. We then construct a simple quantum mechanical model to ...

  17. Graham's law of diffusion: Quantum analogy and non-ideality

    Indian Academy of Sciences (India)

    Administrator

    ideal gas mixture. This equivalence is shown to be lost by the empirical equations of state in presence of an attractive nonideality. The modified forms are noted. ..... say, V1(x), defined by the last term. This makes the subsequent manipulations easy. For example, by employing the VT to the total Hamiltonian HT, we obtain. 1.

  18. Molecular thermodynamics of nonideal fluids

    CERN Document Server

    Lee, Lloyd L

    2013-01-01

    Molecular Thermodynamics of Nonideal Fluids serves as an introductory presentation for engineers to the concepts and principles behind and the advances in molecular thermodynamics of nonideal fluids. The book covers related topics such as the laws of thermodynamics; entropy; its ensembles; the different properties of the ideal gas; and the structure of liquids. Also covered in the book are topics such as integral equation theories; theories for polar fluids; solution thermodynamics; and molecular dynamics. The text is recommended for engineers who would like to be familiarized with the concept

  19. Investigation of Nonideal Plasma Properties

    Science.gov (United States)

    1981-05-01

    a nonideal plasma is the ball lightning phenome- non, which consists of a highly ionized air plasma (n , 10 cm - 3) of low tempera- ture (T % 103 °K...In ball lightning , the plasma appears to be in a highly viscous, quasi-liquid state due to the balance of thermal and (negative) Coulomb interaction

  20. Influence of non-ideality on aerosol growth

    OpenAIRE

    S. Compernolle; K. Ceulemans; J.-F. Müller

    2008-01-01

    Secondary organic aerosol (SOA) is a complex mixture of water and organic molecules. Its composition is determined by the presence of semi-volatile or non-volatile compounds, their vapor pressure and activity coefficient. The activity coefficient is a non-ideality effect and is a complex function of SOA composition. In a previous publication, the detailed chemical mechanism (DCM) for α-pinene oxidation and subsequent aerosol formation BOREAM was presented. In this work, we investigate with th...

  1. Coded communications with nonideal interleaving

    Science.gov (United States)

    Laufer, Shaul

    1991-02-01

    Burst error channels - a type of block interference channels - feature increasing capacity but decreasing cutoff rate as the memory rate increases. Despite the large capacity, there is degradation in the performance of practical coding schemes when the memory length is excessive. A short-coding error parameter (SCEP) was introduced, which expresses a bound on the average decoding-error probability for codes shorter than the block interference length. The performance of a coded slow frequency-hopping communication channel is analyzed for worst-case partial band jamming and nonideal interleaving, by deriving expressions for the capacity and cutoff rate. The capacity and cutoff rate, respectively, are shown to approach and depart from those of a memoryless channel corresponding to the transmission of a single code letter per hop. For multiaccess communications over a slot-synchronized collision channel without feedback, the channel was considered as a block interference channel with memory length equal to the number of letters transmitted in each slot. The effects of an asymmetrical background noise and a reduced collision error rate were studied, as aspects of real communications. The performance of specific convolutional and Reed-Solomon codes was examined for slow frequency-hopping systems with nonideal interleaving. An upper bound is presented for the performance of a Viterbi decoder for a convolutional code with nonideal interleaving, and a soft decision diversity combining technique is introduced.

  2. Mixture

    Directory of Open Access Journals (Sweden)

    Silva-Aguilar Martín

    2011-01-01

    Full Text Available Metals are ubiquitous pollutants present as mixtures. In particular, mixture of arsenic-cadmium-lead is among the leading toxic agents detected in the environment. These metals have carcinogenic and cell-transforming potential. In this study, we used a two step cell transformation model, to determine the role of oxidative stress in transformation induced by a mixture of arsenic-cadmium-lead. Oxidative damage and antioxidant response were determined. Metal mixture treatment induces the increase of damage markers and the antioxidant response. Loss of cell viability and increased transforming potential were observed during the promotion phase. This finding correlated significantly with generation of reactive oxygen species. Cotreatment with N-acetyl-cysteine induces effect on the transforming capacity; while a diminution was found in initiation, in promotion phase a total block of the transforming capacity was observed. Our results suggest that oxidative stress generated by metal mixture plays an important role only in promotion phase promoting transforming capacity.

  3. Modelling of phase equilibria and related properties of mixtures involving lipids

    DEFF Research Database (Denmark)

    Cunico, Larissa

    Many challenges involving physical and thermodynamic properties in the production of edible oils and biodiesel are observed, such as availability of experimental data and realiable prediction. In the case of lipids, a lack of experimental data for pure components and also for their mixtures in open...

  4. Influence of non-ideality on aerosol growth

    Science.gov (United States)

    Compernolle, S.; Ceulemans, K.; Müller, J.-F.

    2008-09-01

    Secondary organic aerosol (SOA) is a complex mixture of water and organic molecules. Its composition is determined by the presence of semi-volatile or non-volatile compounds, their vapor pressure and activity coefficient. The activity coefficient is a non-ideality effect and is a complex function of SOA composition. In a previous publication, the detailed chemical mechanism (DCM) for α-pinene oxidation and subsequent aerosol formation BOREAM was presented. In this work, we investigate with this DCM the impact of non-ideality by simulating smog chamber experiments for α-pinene degradation and aerosol formation. Several versions of the UNIFAC method are tested for this purpose, and missing parameters for e.g. hydroperoxides and nitrates are inferred from fittings to activity coefficient data generated using the SPARC model. It turns out that for most experiments, non-ideality has only a limited impact on the interaction between the organic molecules, and therefore on SOA yields and composition, when water uptake is ignored. Still, for ozonolysis experiments with low amounts of volatile organic carbon (low-VOC), the UNIFAC parameterization of Raatikainen et al. leads to significantly higher SOA yields (by up to a factor 1.6) compared to the ideal case and to other parameterizations. Water uptake is model dependent, in the order: ideal>UNIFAC-Raatikainen>UNIFAC-Peng>UNIFAC-Hansen≍UNIFAC-Magnussen≍UNIFAC-Ming. In the absence of salt dissolution, phase splitting from pure SOA is unlikely.

  5. Nonideal Rayleigh-Taylor mixing

    Energy Technology Data Exchange (ETDEWEB)

    Sharp, David Howland [Los Alamos National Laboratory; Lin, Hyun K [STONY BROOK UNIV.; Iwerks, Justin G [Los Alamos National Laboratory; Gliman, James G [Los Alamos National Laboratory; [NON LANL

    2009-01-01

    Rayleigh-Taylor mixing is a classical hydrodynamic Instability, which occurs when a light fluid pushes against a heavy fluid. The two main sources of nonideal behavior in Rayleigh-Taylor (RT) mixing are regularizations (physical and numerical) which produce deviations from a pure Euler equation, scale Invariant formulation, and non Ideal (i.e. experimental) initial conditions. The Kolmogorov theory of turbulence predicts stirring at all length scales for the Euler fluid equations without regularization. We Interpret mathematical theories of existence and non-uniqueness in this context, and we provide numerical evidence for dependence of the RT mixing rate on nonideal regularizations, in other words indeterminacy when modeled by Euler equations. Operationally, indeterminacy shows up as non unique solutions for RT mixing, parametrized by Schmidt and Prandtl numbers, In the large Reynolds number (Euler equation) limit. Verification and validation evidence is presented for the large eddy simulation algorithm used here. Mesh convergence depends on breaking the nonuniqueness with explicit use of the laminar Schmidt and PrandtJ numbers and their turbulent counterparts, defined in terms of subgrid scale models. The dependence of the mixing rate on the Schmidt and Prandtl numbers and other physical parameters will be illustrated. We demonstrate numerically the influence of initial conditions on the mixing rate. Both the dominant short wavelength Initial conditions and long wavelength perturbations are observed to playa role. By examination of two classes of experiments, we observe the absence of a single universal explanation, with long and short wavelength initial conditions, and the various physical and numerical regularizations contributing In different proportions In these two different contexts.

  6. Nonideal plasmas as non-equilibrium media

    International Nuclear Information System (INIS)

    Morozov, I V; Norman, G E; Valuev, A A; Valuev, I A

    2003-01-01

    Various aspects of the collective behaviour of non-equilibrium nonideal plasmas are studied. The relaxation of kinetic energy to the equilibrium state is simulated by the molecular dynamics (MD) method for two-component non-degenerate strongly non-equilibrium plasmas. The initial non-exponential stage, its duration and the subsequent exponential stage of the relaxation process are studied for a wide range of ion charge, nonideality parameter and ion mass. A simulation model of the nonideal plasma excited by an electron beam is proposed. An approach is developed to calculate the dynamic structure factor in non-stationary conditions. Instability increment is obtained from MD simulations

  7. The physics of non-ideal plasma

    CERN Document Server

    Fortov, Vladimir E

    2000-01-01

    This book is devoted to the physical properties of nonideal plasma which is compressed so strongly that the effects of interparticle interactions govern the plasma behavior. The interest in this plasma was generated by the development of modern technologies and facilities whose operations were based on high densities of energy. In this volume, the methods of nonideal plasma generation and diagnostics are considered. The experimental results are given and the main theoretical models of nonideal plasma state are discussed. The problems of thermodynamics, electro-physics, optics and dynamic stabi

  8. Non-ideality in Born-free energy of solvation in alcohol–water and ...

    Indian Academy of Sciences (India)

    WINTEC

    391. *For correspondence. Non-ideality in Born-free energy of solvation in alcohol–water and dimethylsulfoxide–acetonitrile mixtures: Solvent size ratio and ion size dependence. HEMANT K KASHYAP and RANJIT BISWAS*. Department of Chemical, Biological and Macromolecular Sciences, and Unit for Nanoscience and.

  9. Influence of non-ideality on condensation to aerosol

    Science.gov (United States)

    Compernolle, S.; Ceulemans, K.; Müller, J.-F.

    2009-02-01

    Secondary organic aerosol (SOA) is a complex mixture of water and organic molecules. Its composition is determined by the presence of semi-volatile or non-volatile compounds, their saturation vapor pressure and activity coefficient. The activity coefficient is a non-ideality effect and is a complex function of SOA composition. In a previous publication, the detailed chemical mechanism (DCM) for α-pinene oxidation and subsequent aerosol formation BOREAM was presented. In this work, we investigate with this DCM the impact of non-ideality by simulating smog chamber experiments for α-pinene degradation and aerosol formation and taking the activity coefficient into account of all molecules in the aerosol phase. Several versions of the UNIFAC method are tested for this purpose, and missing parameters for e.g. hydroperoxides and nitrates are inferred from fittings to activity coefficient data generated using the SPARC model. Alternative approaches to deal with these missing parameters are also tested, as well as an activity coefficient calculation method based on Hansen solubility parameters (HSP). It turns out that for most experiments, non-ideality has only a limited impact on the interaction between the organic molecules, and therefore on SOA yields and composition, when water uptake is ignored. The reason is that often, the activity coefficient is on average close to 1 and, specifically for high-VOC experiments, partitioning is not very sensitive on the activity coefficient because the equilibrium is shifted strongly towards condensation. Still, for ozonolysis experiments with low amounts of volatile organic carbon (low-VOC), the UNIFAC parameterization of Raatikainen et al. leads to significantly higher SOA yields (by up to a factor 1.6) compared to the ideal case and to other parameterizations. Water uptake is model dependent, in the order: ideal > UNIFAC-Raatikainen > UNIFAC-Peng > UNIFAC-Hansen ≍ UNIFAC-Magnussen ≍ UNIFAC-Ming. In the absence of salt

  10. Influence of non-ideality on condensation to aerosol

    Directory of Open Access Journals (Sweden)

    S. Compernolle

    2009-02-01

    Full Text Available Secondary organic aerosol (SOA is a complex mixture of water and organic molecules. Its composition is determined by the presence of semi-volatile or non-volatile compounds, their saturation vapor pressure and activity coefficient. The activity coefficient is a non-ideality effect and is a complex function of SOA composition. In a previous publication, the detailed chemical mechanism (DCM for α-pinene oxidation and subsequent aerosol formation BOREAM was presented. In this work, we investigate with this DCM the impact of non-ideality by simulating smog chamber experiments for α-pinene degradation and aerosol formation and taking the activity coefficient into account of all molecules in the aerosol phase. Several versions of the UNIFAC method are tested for this purpose, and missing parameters for e.g. hydroperoxides and nitrates are inferred from fittings to activity coefficient data generated using the SPARC model. Alternative approaches to deal with these missing parameters are also tested, as well as an activity coefficient calculation method based on Hansen solubility parameters (HSP. It turns out that for most experiments, non-ideality has only a limited impact on the interaction between the organic molecules, and therefore on SOA yields and composition, when water uptake is ignored. The reason is that often, the activity coefficient is on average close to 1 and, specifically for high-VOC experiments, partitioning is not very sensitive on the activity coefficient because the equilibrium is shifted strongly towards condensation. Still, for ozonolysis experiments with low amounts of volatile organic carbon (low-VOC, the UNIFAC parameterization of Raatikainen et al. leads to significantly higher SOA yields (by up to a factor 1.6 compared to the ideal case and to other parameterizations. Water uptake is model dependent, in the order: ideal > UNIFAC-Raatikainen > UNIFAC-Peng > UNIFAC-Hansen ≈ UNIFAC-Magnussen ≈ UNIFAC-Ming. In the absence

  11. Non-ideal dust acoustic waves

    International Nuclear Information System (INIS)

    Konefka, F; Contreras, J P; Puerta, J; Castro, E; MartIn, P

    2008-01-01

    The dispersion relation for dust acoustic waves (DA waves) functionally depends on the state equation for the charged dust grains. The ideal gas equation is usually used for studying the effect of temperature on this dispersion relation. However, since the space occupied by the grains can be important in high-density plasmas, the non-ideal effects can be important in this case. This paper analyses the dispersion relation for DA waves, when more precise state equations are used as those described for Pade approximants. The correction to the usual wave equation has been determined and the break point in density, where the ideal gas-state equation has been found. The non-ideal effects are more important for short wavelength ones, and the limits where those effects become important are also studied. Since there are several experimental results for these kinds of waves, the importance of the non-ideal effects in these cases is analysed in detail.

  12. Nonideal mixing in multicomponent lipid/detergent systems

    Energy Technology Data Exchange (ETDEWEB)

    Tsamaloukas, Alekos; Szadkowska, Halina; Heerklotz, Heiko [Biozentrum of the University of Basel, Division of Biophysical Chemistry, Klingelbergstrasse 70, CH-4056 Basel (Switzerland)

    2006-07-19

    A detailed understanding of the mixing properties of membranes to which detergents are added is mandatory for improving the application and interpretation of detergent based protein or lipid extraction assays. For Triton X-100 (TX-100), a nonionic detergent frequently used in the process of solubilizing and purifying membrane proteins and lipids, we present here a detailed study of the mixing properties of binary and ternary lipid mixtures by means of high-sensitivity isothermal titration calorimetry (ITC). To this end the partitioning thermodynamics of TX-100 molecules from the aqueous phase to lipid bilayers composed of various mixtures of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC), egg-sphingomyelin (SM), and cholesterol (cho) are characterized. Composition-dependent partition coefficients K are analysed within the frame of a thermodynamic model developed to describe nonideal mixing in multicomponent lipid/detergent systems. The results imply that POPC, fluid SM, and TX-100 mix almost ideally (nonideality parameters {rho}{sub {alpha}}{sub /{beta}}

  13. Pedagogical Visualization of a Nonideal Carnot Engine

    Directory of Open Access Journals (Sweden)

    Jonas Johansson

    2014-01-01

    Full Text Available We have implemented a visualization tool for the demonstration of a nonideal Carnot engine, operating at finite time. The cycle time can be varied using a slide bar and the pressure-volume, temperature-entropy, power-time, and efficiency-time diagrams change interactively and are shown on one screen. We have evaluated the visualization tool among engineering students at university level during an introductory course on thermodynamics and we review and discuss the outcome of the evaluation.

  14. Model of non-ideal detonation of condensed high explosives

    Science.gov (United States)

    Smirnov, E. B.; Kostitsin, O. V.; Koval, A. V.; Akhlyustin, I. A.

    2016-11-01

    The Zeldovich-Neumann-Doering theory of ideal detonation allows one to describe adequately the detonation of charges with near-critical diameter. For smaller diameters, detonation velocity can differ significantly from an ideal value expected based on equilibrium chemical thermodynamics. This difference is quite evident when using non-ideal explosives; in certain cases, this value can be up to one third of ideal detonation velocity. Numerical simulation of these systems is a very labor-consuming process because one needs to compute the states inside the chemical reaction zone, as well as to obtain data on the equation of state of high-explosive detonation products mixture and on the velocity of chemical reaction; however, these characteristics are poorly studied today. For practical purposes, one can use the detonation shock dynamics model based on interrelation between local velocity of the front and its local curvature. This interrelation depends on both the equation of state of explosion products, and the reaction velocity; but the explicit definition of these characteristics is not needed. In this paper, experimental results are analyzed. They demonstrate interrelation between the local curvature of detonation front and the detonation velocity. Equation of detonation front shape is found. This equation allows us to predict detonation velocity and shape of detonation wave front in arbitrary geometry by integrating ordinary differential equation for the front shape with a boundary condition at the charge edge. The results confirm that the model of detonation shock dynamics can be used to describe detonation processes in non-ideal explosives.

  15. Fungi are involved in the effects of litter mixtures on consumption by shredders

    OpenAIRE

    Jabiol, Jérémy; Chauvet, Eric

    2012-01-01

    International audience; 1. Decomposition of litter mixtures in both terrestrial and aquatic ecosystems often shows non- additive diversity effects on decomposition rate, generally interpreted in streams as a result of the feeding activity of macroinvertebrates. The extent to which fungal assemblages on mixed litter may influence consumption by macroinvertebrates remains unknown. 2. We assessed the effect of litter mixing on all possible three-species combinations drawn from four tree species ...

  16. Verifying reciprocal relations for experimental diffusion coefficients in multicomponent mixtures

    DEFF Research Database (Denmark)

    Medvedev, Oleg; Shapiro, Alexander

    2003-01-01

    into Onsager coefficients and a subsequent symmetry check make it possible to evaluate different thermodynamic models with regard to their possibility of being used for prediction of the transport properties. We performed several checks of this kind for ternary mixtures of hydrocarbons and alcohols, where......The goal of the present study is to verify the agreement of the available data on diffusion in ternary mixtures with the theoretical requirement of linear non-equilibrium thermodynamics consisting in symmetry of the matrix of the phenomenological coefficients. A common set of measured diffusion...... diffusion coefficients into Onsager coefficients for a non-ideal mixture involves derivatives of the chemical potentials and, thus, should be based on a certain thermodynamic model (cubic equation of state (EoS), an activity coefficient model, etc.). Transformation of the Fickian diffusion coefficients...

  17. Phase equilibrium data for potentially hazardous binary mixtures involving dichlorosilane, trichlorosilane and silicon-tetrachloride

    International Nuclear Information System (INIS)

    Nelson, Wayne Michael; Naidoo, Paramespri; Ramjugernath, Deresh

    2015-01-01

    Highlights: • Static-analytic equilibrium measurements for binary mixtures of chlorosilanes. • VLE data for (SiH 2 Cl 2 + SiHCl 3 ) at T = (343.04, 353.04 and 363.00) K. • VLE data for (SiH 2 Cl 2 + SiCl 4 ) at T = (343.28 and 353.07) K. • VLE data for (SiHCl 3 + SiCl 4 ) at T = (323.17, 333.11 and 343.03). • Data modeling with the Peng–Robinson EoS incorporating Wong–Sandler mixing rules. - Abstract: Isothermal (vapour + liquid) equilibrium data were obtained for potentially hazardous binary mixtures of (dichlorosilane + trichlorosilane), (dichlorosilane + tetrachlorosilane), and (trichlorosilane + tetrachlorosilane) using an apparatus based on the “static-analytic” method. The apparatus was specially developed and designed to ensure safe measurement of the flammable, toxic, and corrosive components. The (dichlorosilane + trichlorosilane) system was measured at T = (343.04, 353.04 and 363.00) K, and the (dichlorosilane + tetrachlorosilane) system at T = (343.28 and 353.07) K, and the (trichlorosilane + tetrachlorosilane) system at T = (323.17, 333.11 and 343.03) K. The resulting data were correlated with the Peng–Robinson equation of state coupled with the Wong Sandler mixing rule. The model provided accurate description of all isotherms of the binary systems using temperature-independent interaction parameters regressed for all isotherms.

  18. Predicting diffusivities in dense fluid mixtures

    Directory of Open Access Journals (Sweden)

    C. DARIVA

    1999-09-01

    Full Text Available In this work the Enskog solution of the Boltzmann equation, as corrected by Speedy, together with the Weeks-Chandler-Andersen (WCA perturbation theory of liquids is employed in correlating and predicting self-diffusivities of dense fluids. Afterwards this theory is used to estimate mutual diffusion coefficients of solutes at infinite dilution in sub and supercritical solvents. We have also investigated the behavior of Fick diffusion coefficients in the proximity of a binary vapor-liquid critical point since this subject is of great interest for extraction purposes. The approach presented here, which makes use of a density and temperature dependent hard-sphere diameter, is shown to be excellent for predicting diffusivities in dense pure fluids and fluid mixtures. The calculations involved highly nonideal mixtures as well as systems with high molecular asymmetry. The predicted diffusivities are in good agreement with the experimental data for the pure and binary systems. The methodology proposed here makes only use of pure component information and density of mixtures. The simple algebraic relations are proposed without any binary adjustable parameters and can be readily used for estimating diffusivities in multicomponent mixtures.

  19. Mixture Experiments

    Energy Technology Data Exchange (ETDEWEB)

    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.

  20. Propagation of exponential shock wave in an axisymmetric rotating non-ideal dusty gas

    Science.gov (United States)

    Nath, G.

    2016-09-01

    One-dimensional unsteady isothermal and adiabatic flow behind a strong exponential shock wave propagating in a rotational axisymmetric mixture of non-ideal gas and small solid particles, which has variable azimuthal and axial fluid velocities, is analyzed. The shock wave is driven out by a piston moving with time according to exponential law. The azimuthal and axial components of the fluid velocity in the ambient medium are assumed to be varying and obeying exponential laws. In the present work, small solid particles are considered as pseudo-fluid with the assumption that the equilibrium flow-conditions are maintained in the flow-field, and the viscous-stress and heat conduction of the mixture are negligible. Solutions are obtained in both the cases, when the flow between the shock and the piston is isothermal or adiabatic by taking into account the components of vorticity vector and compressibility. It is found that the assumption of zero temperature gradient brings a profound change in the density, axial component of vorticity vector and compressibility distributions as compared to that of the adiabatic case. To investigate the behavior of the flow variables and the influence on the shock wave propagation by the parameter of non-idealness of the gas overline{b} in the mixture as well as by the mass concentration of solid particles in the mixture Kp and by the ratio of the density of solid particles to the initial density of the gas G1 are worked out in detail. It is interesting to note that the shock strength increases with an increase in G1 ; whereas it decreases with an increase in overline{b} . Also, a comparison between the solutions in the cases of isothermal and adiabatic flows is made.

  1. Non-exponential dynamic relaxation in strongly nonequilibrium nonideal plasmas

    International Nuclear Information System (INIS)

    Morozov, I V; Norman, G E

    2003-01-01

    Relaxation of kinetic energy to the equilibrium state is simulated by the molecular dynamics method for nonideal two-component non-degenerate plasmas. Three limiting examples of initial states of strongly nonequilibrium plasma are considered: zero electron velocities, zero ion velocities and zero velocities of both electrons and ions. The initial non-exponential stage, its duration τ nB and subsequent exponential stages of the relaxation process are studied for a wide range of the nonideality parameter and the ion mass

  2. On a methodology for robust segmentation of nonideal iris images.

    Science.gov (United States)

    Schmid, Natalia A; Zuo, Jinyu

    2010-06-01

    Iris biometric is one of the most reliable biometrics with respect to performance. However, this reliability is a function of the ideality of the data. One of the most important steps in processing nonideal data is reliable and precise segmentation of the iris pattern from remaining background. In this paper, a segmentation methodology that aims at compensating various nonidealities contained in iris images during segmentation is proposed. The virtue of this methodology lies in its capability to reliably segment nonideal imagery that is simultaneously affected with such factors as specular reflection, blur, lighting variation, occlusion, and off-angle images. We demonstrate the robustness of our segmentation methodology by evaluating ideal and nonideal data sets, namely, the Chinese Academy of Sciences iris data version 3 interval subdirectory, the iris challenge evaluation data, the West Virginia University (WVU) data, and the WVU off-angle data. Furthermore, we compare our performance to that of our implementation of Camus and Wildes's algorithm and Masek's algorithm. We demonstrate considerable improvement in segmentation performance over the formerly mentioned algorithms.

  3. Vibrations of stretched damped beams under non-ideal boundary ...

    Indian Academy of Sciences (India)

    Stretched beam vibrations; non-ideal boundary conditions; method of multiple time scales. 1. Introduction. Beams are frequently used as design models for vibration analysis. In such analysis, types of support conditions are important and have direct effect on the solutions and natural fre- quencies. Different types of supports ...

  4. Vibrations of stretched damped beams under non-ideal boundary ...

    Indian Academy of Sciences (India)

    A simply supported damped Euler–Bernoulli beam with immovable end conditions are considered. The concept of non-ideal boundary conditions is applied to the beam problem. In accordance, the boundaries are assumed to allow small deflections and moments. Approximate analytical solution of the problem is found ...

  5. Description of adsorption in liquid chromatography under non-ideal conditions.

    Science.gov (United States)

    Ortner, Franziska; Ruppli, Chantal; Mazzotti, Marco

    2018-04-17

    A thermodynamically consistent description of binary adsorption in reversed phase chromatography is presented, accounting for thermodynamic nonidealities in the liquid and the adsorbed phase. The investigated system involves the adsorbent Zorbax 300SB-C18, as well as phenetole (PNT) and 4-tert-butylphenol (TBP) as solutes and methanol and water as inert components forming the eluent. The description is based on adsorption isotherms which are a function of the liquid phase activities, in order to account for non-idealities in the liquid phase. Liquid phase activities are calculated with a UNIQUAC model established in this work, based on experimental phase equilibrium data. The binary interaction in the adsorbed phase is described by the adsorbed solution theory (AST), assuming an ideal (IAST) or real (RAST) adsorbed phase. Implementation of the established adsorption model in a chromatographic code achieves a quantitative description of experimental elution profiles, with feed compositions exploiting the entire miscible region, and involving a broad range of different eluent compositions (ratio methanol:water). The quantitative agreement of model and experimental data serves as a confirmation of the underlying physical (thermodynamic) concepts, and of their applicability to a broad range of operating conditions.

  6. Description of nonideal Lorentz transformation for electromagnetic nulls

    Science.gov (United States)

    Yang, Shu-Di; Wang, Xiao-Gang

    2018-01-01

    To identify characteristic topological features of the electromagnetic field in an arbitrary reference frame, Lorentz transformation properties of an electromagnetic field near a null point are explored under certain constraints, in different nonideal magnetohydrodynamics (MHD) situations for linear nulls, showing violations of topology accordingly. It is shown that Newcomb's condition for conservation of covariant magnetic surfaces does not necessarily mean conservation of field line topology under Lorentz transformation. Characterizations of the violation of magnetic topology under Lorentz transformation are given. A method describing local magnetic null webs by combination of the first and second order Taylor expansions is also proposed, whose transformation properties with possible nonideal influences are discussed in the frame of resistive MHD. These results are important for establishing a reasonable range of the fieldline picture and thus the dynamical analysis based on magnetic fieldlines.

  7. Determination of performance of non-ideal aluminized explosives.

    Science.gov (United States)

    Keshavarz, Mohammad Hossein; Mofrad, Reza Teimuri; Poor, Karim Esmail; Shokrollahi, Arash; Zali, Abbas; Yousefi, Mohammad Hassan

    2006-09-01

    Non-ideal explosives can have Chapman-Jouguet (C-J) detonation pressure significantly different from those expected from existing thermodynamic computer codes, which usually allows finding the parameters of ideal detonation of individual high explosives with good accuracy. A simple method is introduced by which detonation pressure of non-ideal aluminized explosives with general formula C(a)H(b)N(c)O(d)Al(e) can be predicted only from a, b, c, d and e at any loading density without using any assumed detonation products and experimental data. Calculated detonation pressures show good agreement with experimental values with respect to computed results obtained by complicated computer code. It is shown here how loading density and atomic composition can be integrated into an empirical formula for predicting detonation pressure of proposed aluminized explosives.

  8. Nonideal ultrathin mantle cloak for electrically large conducting cylinders.

    Science.gov (United States)

    Liu, Shuo; Zhang, Hao Chi; Xu, He-Xiu; Cui, Tie Jun

    2014-09-01

    Based on the concept of the scattering cancellation technique, we propose a nonideal ultrathin mantle cloak that can efficiently suppress the total scattering cross sections of an electrically large conducting cylinder (over one free-space wavelength). The cloaking mechanism is investigated in depth based on the Mie scattering theory and is simultaneously interpreted from the perspective of far-field bistatic scattering and near-field distributions. We remark that, unlike the perfect transformation-optics-based cloak, this nonideal cloaking technique is mainly designed to minimize simultaneously several scattering multipoles of a relatively large geometry around considerably broad bandwidth. Numerical simulations and experimental results show that the antiscattering ability of the metasurface gives rise to excellent total scattering reduction of the electrically large cylinder and remarkable electric-field restoration around the cloak. The outstanding cloaking performance together with the good features of and ultralow profile, flexibility, and easy fabrication predict promising applications in the microwave frequencies.

  9. Becoming Autonomous: Nonideal Theory and Educational Autonomy

    Science.gov (United States)

    Wilson, Terri S.; Ryg, Matthew A.

    2015-01-01

    Autonomy operates as a key term in debates about the rights of families to choose distinct approaches to education. Yet, what autonomy means is often complicated by the actual circumstances and contexts of schools, families, and children. In this essay, Terri S. Wilson and Matthew A. Ryg focus on the challenges involved in translating an ideal of…

  10. Prediction of solubility in nonideal multicomponent systems using the UNIFAC group contribution model.

    Science.gov (United States)

    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.

  11. Non-ideal magnetohydrodynamics on a moving mesh

    Science.gov (United States)

    Marinacci, Federico; Vogelsberger, Mark; Kannan, Rahul; Mocz, Philip; Pakmor, Rüdiger; Springel, Volker

    2018-02-01

    In certain astrophysical systems the commonly employed ideal magnetohydrodynamics (MHD) approximation breaks down. Here, we introduce novel explicit and implicit numerical schemes of ohmic resistivity terms in the moving-mesh code AREPO. We include these non-ideal terms for two MHD techniques: the Powell 8-wave formalism, and a constrained transport scheme, which evolves the cell-centred magnetic vector potential. We test our implementation against problems of increasing complexity, such as one- and two-dimensional diffusion problems, and the evolution of progressive and stationary Alfvén waves. On these test problems our implementation recovers the analytic solutions to second order accuracy. As first applications, we investigate the tearing instability in magnetised plasmas and the gravitational collapse of a rotating magnetised gas cloud. In both systems resistivity plays a key role. In the former case, it allows for the development of the tearing instability through reconnection of the magnetic field lines. In the latter, the adopted (constant) value of ohmic resistivity has an impact on both the gas distribution around the emerging proto-star and the mass loading of magnetically-driven outflows. Our new non-ideal MHD implementation opens up the possibility to study magneto-hydrodynamical systems on a moving mesh beyond the ideal MHD approximation.

  12. Thermodynamic and Experimental Study of the Energetic Cost Involved in the Capture of Carbon Dioxide by Aqueous Mixtures of Commonly Used Primary and Tertiary Amines.

    Science.gov (United States)

    Arcis, Hugues; Coulier, Yohann; Coxam, Jean-Yves

    2016-01-05

    The capture of carbon dioxide with chemical solvents is one solution to mitigate greenhouse gas emissions from anthropogenic sources and thus tackle climate change. Recent research has been focused on optimizing new kinds of advanced absorbents including aqueous amine blends, but critical downsides such as the large energetic cost involved with the industrial process remain. To address this issue, a better understanding of the energetic interactions existing in solution is necessary. In this paper, we report direct experimental measurements of the energy cost involved in the solvation of CO2 in two aqueous amine blends at different temperatures. The chemical solvents were designed as aqueous mixtures of commonly used primary and tertiary amines to study the influence of the different chemical properties inferred by the amine class. We have also applied a thermodynamic model to represent the energetic effects that take place in solution during CO2 dissolution in these mixtures, where all parameters were taken from previous studies focused on single amine absorbents. The noteworthy agreement observed with the reported experimental heats of absorption and with literature vapor liquid equilibrium properties confirmed the relevance of the underlying molecular mechanisms considered in our model, and suggest that this model would prove useful to investigate CO2 dissolution in other amine blends.

  13. Dynamic optimization of a dead-end filtration trajectory: non-ideal cake filtration

    NARCIS (Netherlands)

    Blankert, B.; Kattenbelt, C.; Betlem, Bernardus H.L.; Roffel, B.

    2007-01-01

    A control strategy aimed at minimizing energy consumption is formulated for non-ideal dead-end cake filtration with an inside-out hollow fiber ultrafiltration membrane system. The non-ideal behavior was assumed to originate from cake compression, non-linear cake resistance and a variable pump

  14. Dynamic optimization of a dead-end filtration trajectory : Non-ideal cake filtration

    NARCIS (Netherlands)

    Blankert, Bastiaan; Kattenbelt, Carolien; Betlem, Ben H.L.; Roffel, Brian

    2007-01-01

    A control strategy aimed at minimizing energy consumption is formulated for non-ideal dead-end cake filtration with an inside-out hollow fiber ultrafiltration membrane system. The non-ideal behavior was assumed to originate from cake compression, non-linear cake resistance and a variable pump

  15. The Behavior of PCM/PM Receivers in Non-Ideal Channels

    Science.gov (United States)

    Nguyen, Tien Manh

    1994-01-01

    This paper presents a performance evaluation of residual carrier commuication systems that employ a PCM/PM modulation technique operating over non-ideal channels. The non-ideal channels under investigation include data asymmetry, an unbalanced data stream (i.e., transition density deviates from 0.5) and InterSymbol Interference (ISI).

  16. The Need for Roots Redux: On the Supposed Disciplinary Right to a Nonideal Theory

    Science.gov (United States)

    Keehn, Gabriel

    2016-01-01

    Educational philosophy, broadly speaking, has turned sharply in the direction of nonideal theorizing in recent years. The thesis of this paper is that this turn is premature, and will ultimately bear very little fruit for educational philosophy as a discipline. The author's argument proceeds through a discussion of the history of nonideal theory…

  17. Getting the Distance Right: Ideal and Nonideal Theory in Philosophy of Education

    Science.gov (United States)

    Shuffelton, Amy B.

    2015-01-01

    When the debate over the value of ideal and nonideal theory crosses from political philosophy into philosophy of education, do the implications of the debate shift, and, if so, how? In this piece, Amy Shuffelton considers the premise that no normative political theory, ideal or nonideal, is of any use to human beings unless it can be affiliated…

  18. SU2 : The Open-Source Software for Non-ideal Compressible Flows

    NARCIS (Netherlands)

    Pini, M.; Vitale, S.; Colonna di Paliano, Piero; Gori, G; Guardone, A.M.A.; Economon, TD; Alonso, J; Palacios, F

    2017-01-01

    The capabilities of the open-source SU2 software suite for the numerical simulation of viscous flows over unstructured grid are extended to non-ideal compressible-fluid dynamics (NICFD). A built-in thermodynamic library is incorporated to account for the non-ideal thermodynamic characteristics of

  19. White noise excited non-ideal elasto-plastic oscillator

    DEFF Research Database (Denmark)

    Ditlevsen, Ove Dalager; Tarp-Johansen, Niels Jacob

    1997-01-01

    , and are in file available for analysis. The column connection between the two top traverses were made of aluminum with a linear-elastic non-ideal plastic behavior, and the columns were therefore renewed after each experiment. The two other connections were made of steel with a purely linear-elastic behavior...... of the plastic displacement process. This paper presents a determination of the experimentally estimated statistical properties of the plastic response by use of Slepian model process theory as the basis for a numerical simulation algorithm. Solely the given defining parameters of the experimental flame are used...... on an oscillator of more than one degree of freedom. Applied to the experimental frame the calculations give excellent predictions of the main distributional properties of the plastic displacement process....

  20. Magnetic field-aligned electric potentials in nonideal plasma flows

    Science.gov (United States)

    Schindler, K.; Hesse, M.; Birn, J.

    1991-01-01

    The electric field component parallel to the magnetic field arising from plasma flows which violate the frozen-in field condition of ideal magnetohydrodynamics is discussed. The quantity of interest is the potential U = integral E parallel ds where the integral is extended along field lines. It is shown that U can be directly related to magnetic field properties, expressed by Euler potentials, even when time-dependence is included. These results are applicable to earth's magnetosphere, to solar flares, to aligned-rotator models of compact objects, and to galactic rotation. On the basis of order-of-magnitude estimates, these results support the view that parallel electric fields associated with nonideal plasma flows might play an important role in cosmic particle acceleration.

  1. Numerical study of non-ideal Vlasov-BGK plasmas

    International Nuclear Information System (INIS)

    Levchenko, V.D.; Sigov, Y.S.; Premuda, F.

    1995-01-01

    A relatively simple quasi-classical description of quantum plasmas using as first approximation the Bhatnagar-Gross-Krook (BGK) collision integral, if combined with the modern numerical simulation methods, might be effective tool of a deep study of non-ideal plasma kinetics in a variety of urgent applications as inertial confinement and cold fusion, transport and collective properties of highly condensed plasmas in liquid metals, semi- and superconductors and others. Consider one-dimensional degenerate plasma consisting of thermal electrons and thermal bosons (deuterons) in the vicinity of the equilibrium Fermi- and Bose-type distributions respectively. In the frame of our rough mixed model we solve Vlasov-BGK-Poisson eqs using simplified version of the SUR code

  2. Novel self-similar rotating solutions of nonideal transverse magnetohydrodynamics

    Science.gov (United States)

    Shokri, M.; Sadooghi, N.

    2017-12-01

    The evolution of electromagnetic and thermodynamic fields in a nonideal fluid is studied in the framework of ultrarelativistic transverse magnetohydrodynamics (MHD), which is essentially characterized by electric and magnetic fields being transverse to the fluid velocity and translational invariance in the transverse plane. Extending the method of self-similar solutions of relativistic hydrodynamics to the case of nonconserved charges, the differential equations of nonideal transverse MHD are solved, and two novel sets of self-similar solutions are derived. The first set turns out to be a boost-invariant and exact solution, which is characterized by nonrotating electric and magnetic fields. The second set is a nonboost-invariant solution, which is characterized by rotating electric and magnetic fields. The rotation occurs with increasing rapidity η , as the angular velocity is defined by ω0≡∂ζ/∂η =∂ϕ/∂η , with ζ and ϕ being the angles of local electric and magnetic vectors with respect to a certain fixed axis in the transverse plane. For both sets of solutions, the electric and magnetic fields are either parallel or antiparallel to each other in the local rest frame of the fluid. Performing a complete numerical analysis, the effects of finite electric conductivity as well as electric and magnetic susceptibilities of the medium on the evolution of rotating and nonrotating MHD solutions are explored, and the interplay between the angular velocity ω0 and these quantities is scrutinized. The lifetime of electromagnetic fields and the evolution of the temperature of the electromagnetized fluid are shown to be affected by ω0.

  3. Self-similar flow behind a spherical shock wave in a non-ideal dusty gas under a gravitational field: Isothermal flow

    Science.gov (United States)

    Nath, G.

    2013-10-01

    Similarity solutions are obtained for one-dimensional unsteady isothermal flow of a dusty gas behind a spherical shock wave with time dependent energy input. The dusty gas is assumed to be a mixture of non-ideal (or perfect) gas and small solid particles, in which solid particles are continuously distributed. It is assumed that the equilibrium flow-conditions are maintained, and the viscous stress and heat conduction of the mixture are negligible. The medium is taken to be under the influence of the gravitational field due to a heavy nucleus at the origin (Roche model). The total energy of the flow-field behind the shock is increasing. The effects of an increase in the mass concentration of solid particles, the ratio of the density of the solid particles to the initial density of the gas, the gravitational parameter (or shock Mach number), and the parameter of non-idealness of the gas in the mixture, are investigated. It is shown that due to presence of gravitational field the isothermal compressibility of the medium and the flow-variables increases and the shock strength decreases. A comparison has also been made between the medium with and without gravitational field. The shock waves in dusty medium can be important for description of star formation, shocks in supernova explosions, etc.

  4. A Unified Theory of Non-Ideal Gas Lattice Boltzmann Models

    Science.gov (United States)

    Luo, Li-Shi

    1998-01-01

    A non-ideal gas lattice Boltzmann model is directly derived, in an a priori fashion, from the Enskog equation for dense gases. The model is rigorously obtained by a systematic procedure to discretize the Enskog equation (in the presence of an external force) in both phase space and time. The lattice Boltzmann model derived here is thermodynamically consistent and is free of the defects which exist in previous lattice Boltzmann models for non-ideal gases. The existing lattice Boltzmann models for non-ideal gases are analyzed and compared with the model derived here.

  5. Involvement of α-, γ- and δ-Tocopherol Isomers from Pumpkin (Cucurbita pepo L. Seed Oil or Oil Mixtures in the Biphasic DPPH˙ Disappearance Kinetics

    Directory of Open Access Journals (Sweden)

    Dalibor Broznić

    2016-01-01

    Full Text Available The antioxidant activity of three types of pumpkin seed oil or oil mixtures (cold-pressed, produced from roasted seed paste and salad produced in the northern part of Croatia and the kinetics of their behaviour as free radical scavengers were investigated using DPPH˙. In addition, the involvement of oil tocopherol isomers (α-, γ- and δ- in different steps of DPPH˙ disappearance and their impact on the rate of reaction were analysed. The kinetics of DPPH˙ disappearance is a two-step process. In the first step, rapid disappearance of DPPH˙ occurs during the first 11 min of the reaction, depending on the oil type, followed by a slower decline in the second step. To describe DPPH˙ disappearance kinetics, six mathematical models (mono- and biphasic were tested. Our findings showed that γ- and δ-tocopherols affected DPPH˙ disappearance during the first step, and α-tocopherol in the second step of the reaction. Moreover, α-tocopherol demonstrated 30 times higher antioxidant activity than γ- and δ-tocopherols. The results indicated the biphasic double-exponential behaviour of DPPH˙ disappearance in oil samples, due to the complexity of reactions that involve different tocopherol isomers and proceed through different chemical pathways.

  6. The influence of hydrogen bonds and preferential solvation on spectroscopic properties of methyl p-dimethylaminobenzoate and its ortho derivative in binary solvent mixture

    Science.gov (United States)

    Józefowicz, Marek

    2011-05-01

    Using the steady-state spectroscopic technique, we have studied the spectroscopic properties of methyl p-dimethylaminobenzoate and its ortho derivative in binary mixture where one of components is capable to form hydrogen bonds with the solute molecules. Non-linear solvatochromic shifts of the absorption, locally excited (LE) and intramolecular charge transfer (ICT) fluorescence bands are observed for both fluorophores. This non-linearity has been explained as due to three main causes: non-ideal behavior of the solvent mixture, specific solute-solvent association, and dielectric enrichment of the solvent around the polar solutes. The results of spectroscopic measurements were used to calculate, according to Mazurenko's, Bakhshiev's and Kiselev's theories, the free energy of the reorientational interaction for a studied molecules, the number of more polar solvent molecules involved in the first solvation shell and the fluorescence spectra of solvates having different number of more polar component in the first solvation shell.

  7. Mutual optical intensity propagation through non-ideal mirrors.

    Science.gov (United States)

    Meng, Xiangyu; Shi, Xianbo; Wang, Yong; Reininger, Ruben; Assoufid, Lahsen; Tai, Renzhong

    2017-09-01

    The mutual optical intensity (MOI) model is extended to include the propagation of partially coherent radiation through non-ideal mirrors. The propagation of the MOI from the incident to the exit plane of the mirror is realised by local ray tracing. The effects of figure errors can be expressed as phase shifts obtained by either the phase projection approach or the direct path length method. Using the MOI model, the effects of figure errors are studied for diffraction-limited cases using elliptical cylinder mirrors. Figure errors with low spatial frequencies can vary the intensity distribution, redistribute the local coherence function and distort the wavefront, but have no effect on the global degree of coherence. The MOI model is benchmarked against HYBRID and the multi-electron Synchrotron Radiation Workshop (SRW) code. The results show that the MOI model gives accurate results under different coherence conditions of the beam. Other than intensity profiles, the MOI model can also provide the wavefront and the local coherence function at any location along the beamline. The capability of tuning the trade-off between accuracy and efficiency makes the MOI model an ideal tool for beamline design and optimization.

  8. pH variations during diafiltration due to buffer nonidealities.

    Science.gov (United States)

    Baek, Youngbin; Yang, Deyu; Singh, Nripen; Arunkumar, Abhiram; Ghose, Sanchayita; Li, Zheng Jian; Zydney, Andrew L

    2017-11-01

    Diafiltration is used for final formulation of essentially all biotherapeutics. Several studies have demonstrated that buffer/excipient concentrations in the final diafiltered product can be different than that in the diafiltration buffer due to interactions between buffer species and the protein product. However, recent work in our lab has shown variations in solution pH that are largely independent of the protein concentration during the first few diavolumes. Our hypothesis is that these pH variations are due to nonidealities in the acid-base equilibrium coefficient. A model was developed for the diafiltration process accounting for the ionic strength dependence of the pK a . Experimental results obtained using phosphate and histidine buffers were in excellent agreement with model predictions. A decrease in ionic strength leads to an increase in the pK a for the phosphate buffer, causing a shift in the solution pH, even under conditions where the initial feed and the diafiltration buffer are at the same pH. This effect could be eliminated by matching the ionic strength of the feed and diafiltration buffer. The experimental data and model provide new insights into the factors controlling the pH profile during diafiltration processes. © 2017 American Institute of Chemical Engineers Biotechnol. Prog., 33:1555-1560, 2017. © 2017 American Institute of Chemical Engineers.

  9. Suicide intervention and non-ideal Kantian theory.

    Science.gov (United States)

    Cholbi, Michael J

    2002-01-01

    Philosophical discussions of the morality of suicide have tended to focus on its justifiability from an agent's point of view rather than on the justifiability of attempts by others to intervene so as to preserve it. This paper addresses questions of suicide intervention within a broadly Kantian perspective. In such a perspective, a chief task is to determine the motives underlying most suicidal behaviour. Kant wrongly characterizes this motive as one of self-love or the pursuit of happiness. Psychiatric and scientifc evidence suggests that suicide is instead motivated by nihilistic disenchantment with the possibility of happiness which, at its apex, results in the loss of the individual's conception of her practical identity. Because of this, methods of intervention that appeal to agents' happiness, while morally benign, will prove ineffective in forestalling suicide. At the same time, more aggressive methods violate the Kantian concern for autonomy. This apparent dilemma can be resolved by seeing suicide intervention as an action undertaken in non-ideal circumstances, where otherwise unjustified manipulation, coercion, or paternalism are morally permitted.

  10. A non-ideal MHD model for structure formation

    Science.gov (United States)

    Karmakar, Pralay Kumar; Sarma, Pankaj

    2018-02-01

    The evolutionary initiation dynamics of triggered planetary structure formation is indeed a complex process yet to be well understood. We herein develop a theoretical classical model to see the gravitational fragmentation kinetics of the viscoelastic non-ideal magneto-hydro-dynamic (MHD) fabric. The inhomogeneous planetary disk is primarily composed of heavier dust grains (strongly correlated) together with relatively lighter electrons, ions and neutrals (weakly correlated) in a mean-fluidic approximation. A normal harmonic mode analysis results in a quadratic dispersion relation of a unique shape. It is demonstrated that the growth rate of the MHD fluctuations (magnetosonic) contributing to the planet formation rate, apart from the wave vector and its projection orientation, has a pure explicit dependency on the viscoelastic parameters. The analysis specifically shows that the effective generalized viscosity (χ) , viscoelastic relaxation time (τm) , and K-orientation (θ) play as destabilizing agencies against the non-local gravitational disk collapse. The relevancy is briefly indicated in the real astronomical context of bounded planetary structure formation and evolution.

  11. Na Cl ion pair association in water-DMSO mixtures: Effect of ion pair ...

    Indian Academy of Sciences (India)

    stronger than the water-water hydrogen bond, DMSO– water mixtures exhibit strong non-ideal behavior7 in ... from ideal behavior. ∗. For correspondence. Liu et al., have shown that in the gas phase, ab inito calculations very accurately match the experimental value of interaction energy minimum between the Na. + and Cl.

  12. Behavior of the reversed field pinch with nonideal boundary conditions

    International Nuclear Information System (INIS)

    Ho, Yung-Lung.

    1988-11-01

    The linear and nonlinear magnetohydrodynamic stability of current-driven modes are studied for a reversed field pinch with nonideal boundary conditions. The plasma is bounded by a thin resistive shell surrounded by a vacuum region out to a radius at which a perfectly conducting wall is situated. The distant wall and the thin shell problems are studied by removing either the resistive shell or the conducting wall. Linearly, growth rates of tearing modes and kink modes are calculated by analytical solutions based on the modified Bessel function model for the equilibrium. The effects of variation of the shell resistivity and wall proximity on the growth rates are investigated. The modes that may be important in different parameter regimes and with different boundary conditions are identified. The nonlinear behaviors are studied with a three-dimensional magnetohydrodynamics code. The fluctuations generally rise with increasing distance between the conducting wall and the plasma. The enhanced fluctuation induced v x b electric field primarily oppose toroidal current; hence, loop voltage must increase to sustain the constant. Quasilinear interaction between modes typically associated with the dynamo action is identified as the most probable nonlinear destabilization mechanism. The helicity and energy balance properties of the simulation results are discussed. The interruption of current density along field lines intersecting the resistive shell is shown to lead to surface helicity leakage. This effect is intimately tied to stability, as fluctuation induced v x b electric field is necessary to transport the helicity to the surface. In this manner, all aspects of helicity balance, i.e., injection, transport, and dissipation, are considered self-consistently. The importance of the helicity and energy dissipation by the mean components of the magnetic field and current density is discussed. 88 refs., 41 figs., 3 tabs

  13. Bloch walls and the non-ideal bose gas spectrum

    International Nuclear Information System (INIS)

    Vitiello, S.A.S.

    1986-05-01

    The quasi-particle spectrum of non-ideal Bose gas with domain walls in the condensate is investigated. The existence of such a system is determined from solutions of Gross-Pitaevskii equation which represent many-soliton systems. The walls which make the condensate non-uniform are responsible for density and velocity fields ρ(x) and υ(x) repectively. In the laboratory, the Bogoliubov spectrum, supposed to be true for an uniform condensate at rest, is changed due to the velocity field to which the quasi-particles are submited. The spectrum in the laboratory frame is obtained by considering the Galileu invariance principle and the interaction energy between the quasi-particle and its medium. The importance in considering the last two facts is illustrated by the analyse of a constant density condensate which moves uniformly in the laboratory. The many-soliton spectrum configuration and structure function are studied by the Monte Carlo method. In an approximation that assumes the quasi-particle to be point like, the condensate can be treated as locally uniform. For each event the position x of a quasi-particle and its momentum in a frame with velocity υ(x) are determined. Thus, by a convenient Galileu transformation the energy spectrum in the laboratory an be obtained. The results show a phonon spectrum which splits in two branches in the high momenta region. In this region the lower energy branch exibiths a point of minimum. Analogies with the He II are explored. (author) [pt

  14. Spectrophotometric studies on the formation of adducts involved in synergistic extraction of uranium (IV) by mixtures of HTTA and neutral donors

    International Nuclear Information System (INIS)

    Patil, S.K.; Ramakrishna, V.V.; Ramanujam, A.

    1979-01-01

    Adduct formation between U(TTA) 4 and several neutral donor (S) was investigated by utilizing the changes in the absorption spectra of U(IV) resulting from the addition of neutral donors to a solution of U(TTA) 4 . All the donors used in the present work from 1:1 adducts with U(TTA) 4 . From the spectral changes, the equilibrium constants βsub(AB) for the adduct formation reaction viz U(TTA) 4 S reversible U(TTA) 4 .S were calculated for a few neutral donors. The log βsub(AB) values obtained in benzene medium, are :TOPO (6.23), TBPO (6.13), TPPO (4.72), DBBP(4.04) TBP(3.04), TIOTP(1.27) and MIBK(-0.10) and a value of 3.98 for TOPO in chloroform medium. The adduct formation was found to result in increasing the coordination number of U(IV) from 8 in U(TTA) 4 to 9 in the adducts it forms with the neutral donors. Similar absorption spectral studies with U(DBM) 4 revealed that it forms much weaker adducts than the corresponding ones with U(TTA) 4 . The absorption spectra of the organic extracts of U(IV) from perchloric acid with mixtures of HTTA and a neutral donor were identical with the spectra of the adduct between U(TTA) 4 and the neutral donor. This suggested that the adduct species viz U(TTA) 4 .S is involved in the synergistic extraction of U(IV). The extraction constants relating to the synergistic extraction of U(IV), from aqueous perchloric acid into benzene solutions of HTTA and some of the neutral donors, were derived. (author)

  15. SOLGASMIX-PV, Chemical System Equilibrium of Gaseous and Condensed Phase Mixtures

    International Nuclear Information System (INIS)

    Besmann, T.M.

    1986-01-01

    1 - Description of program or function: SOLGASMIX-PV, which is based on the earlier SOLGAS and SOLGASMIX codes, calculates equilibrium relationships in complex chemical systems. Chemical equilibrium calculations involve finding the system composition, within certain constraints, which contains the minimum free energy. The constraints are the preservation of the masses of each element present and either constant pressure or volume. SOLGASMIX-PV can calculate equilibria in systems containing a gaseous phase, condensed phase solutions, and condensed phases of invariant and variable stoichiometry. Either a constant total gas volume or a constant total pressure can be assumed. Unit activities for condensed phases and ideality for solutions are assumed, although nonideal systems can be handled provided activity coefficient relationships are available. 2 - Restrictions on the complexity of the problem: The program is designed to handle a maximum of 20 elements, 99 substances, and 10 mixtures, where the gas phase is considered a mixture. Each substance is either a gas or condensed phase species, or a member of a condensed phase mixture

  16. Non-Ideality in Solvent Extraction Systems: PNNL FY 2014 Status Report

    Energy Technology Data Exchange (ETDEWEB)

    Levitskaia, Tatiana G. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Chatterjee, Sayandev [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Pence, Natasha K. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2014-09-30

    The overall objective of this project is to develop predictive modeling capabilities for advanced fuel cycle separation processes by gaining a fundamental quantitative understanding of non-ideality effects and speciation in relevant aqueous and organic solutions. Aqueous solutions containing actinides and lanthanides encountered during nuclear fuel reprocessing have high ionic strength and do not behave as ideal solutions. Activity coefficients must be calculated to take into account the deviation from ideality and predict their behavior. In FY 2012-2013, a convenient method for determining activity effects in aqueous electrolyte solutions was developed. Our initial experiments demonstrated that water activity and osmotic coefficients of the electrolyte solutions can be accurately measured by the combination of two techniques, a Water Activity Meter and Vapor Pressure Osmometry (VPO). The water activity measurements have been conducted for binary lanthanide solutions in wide concentration range for all lanthanides (La-Lu with the exception of Pm). The osmotic coefficients and Pitzer parameters for each binary system were obtained by the least squares fitting of the water activity data. However, application of Pitzer model for the quantitative evaluation of the activity effects in the multicomponent mixtures is difficult due to the large number of the required interaction parameters. In FY 2014, the applicability of the Bromley model for the determination of the Ln(NO3)3 activity coefficients was evaluated. The new Bromley parameters for the binary Ln(NO3)3 electrolytes were obtained based on the available literature and our experimental data. This allowed for the accurate prediction of the Ln(NO3)3 activity coefficients for the binary Ln(NO3)3 electrolytes. This model was then successfully implemented for the determination of the Ln(NO3)3 activity

  17. Direct Initiation of Detonation by Non-Ideal Blast Waves

    Science.gov (United States)

    1977-06-01

    include the following events. HFirt, a shock’ wave travels through a combustible mixture, raising its temperature and pressure. Next an induction zone... hidrogen - oxygen system is given by the 2ormlula, A rL .. A ex(F/T 7 where A is caulled the pro-eqpt’nuntial factor, ’) 10, i uitc oxygenl ouncentra...is now nccessary to specify the combustible mixture and the chemi- cal kinetics to be studied. For simplicity, all computer runs were made with the

  18. Non-Ideal Compressible Fluid Dynamics: A Challenge for Theory

    Science.gov (United States)

    Kluwick, A.

    2017-03-01

    The possibility that compression as well as rarefaction shocks may form in single phase vapours was envisaged first by Bethe (1942). However calculations based on the Van der Waals equation of state indicated that the latter type of shock is possible only if the specific heat at constant volume cv divided by the universal gas constant R is larger than about 17.5 which he considered too large to be satisfied by real fluids. This conclusion was contested by Thompson (1971) who showed that the type of shock capable of forming in arbitrary fluids is determined by the sign of the thermodynamic quantity to which he referred to as fundamental derivative of gas dynamics. Here v, p, s and c denote the specific volume, the pressure, the entropy and the speed of sound. Thompson and co-workers also showed that the required condition for the existence of rarefaction shocks, that Γ may take on negative values, is indeed satisfied for a number of hydrocarbon and fluorocarbon vapours. This finding spawned a burst of theoretical studies elaborating on the unusual and often counterintuitive behaviour of shocks with rarefaction shocks present. These produced both results of theoretical character but also results suggesting the practical importance of Non-Ideal Compressible Fluid Dynamics in general. The present paper addresses some of the challenges encountered in connection with the theoretical treatment of the associated flow behaviour. Weakly nonlinear acoustic waves of finite amplitude serve as a starting point. Here mixed rather than strictly positive nonlinearity generates a wealth of phenomena not possible in perfect gases. Examples of steady flows where these non-classical effects play a decisive role (and which may be useful also for future experimental work) are quasi one-dimensional nozzle flows and transonic two-dimensional flows past corners. The study of viscous effects concentrates on laminar flows of boundary layer type. Here non-classical phenomena are caused by the

  19. New expressions to describe solution nonideal osmotic pressure, freezing point depression, and vapor pressure.

    Science.gov (United States)

    Fullerton, G D; Zimmerman, R J; Cantu, C; Cameron, I L

    1992-12-01

    New empirical expressions for osmotic pressure, freezing point depression, and vapor pressure are proposed based on the concepts of volume occupancy and (or) hydration force. These expressions are in general inverse relationships in comparison to the standard ideal expressions for the same properties. The slopes of the new equations are determined by the molecular weight of the solute and known constants. The accuracy and precision of the molecular weights calculated from the slope are identical and approximately 1% for the experiments reported here. The nonideality of all three colligative expressions is described by a dimensionless constant called the solute-solvent interaction parameter I. The results on sucrose have the same I = 0.26 for all three solution properties. The nonideality parameter I increased from 0.26 on sucrose to 1.7 on hemoglobin to successfully describe the well-known nonideal response of macromolecules.

  20. Simple correlation for predicting detonation velocity of ideal and non-ideal explosives.

    Science.gov (United States)

    Keshavarz, Mohammad Hossein

    2009-07-30

    This paper describes a simple method for prediction of detonation velocity of ideal and non-ideal explosives. A non-ideal aluminized and nitrated explosive can have Chapman-Jouguet detonation velocity significantly different from that expected from existing thermodynamic computer codes for equilibrium and steady-state calculations. Detonation velocity of explosives with general formula C(a)H(b)N(c)O(d)Al(e) can be predicted only from values of a, b, c, d, e and a specific structural parameter without using any assumed detonation products, heat of formation and experimental data. Predicted detonation velocities by this procedure for ideal and non-ideal explosives show good agreement with respect to experimental values as compared to computed results of BKWR and BKWS equations of state.

  1. Graham's law of diffusion: Quantum analogy and non-ideality

    Indian Academy of Sciences (India)

    We focus attention on two equivalent forms of Graham's law of diffusion that is valid for an ideal gas mixture. ... Department of Chemistry, B.C. College, Asansol 713 304; Department of Theoretical Physics, Indian Association for the Cultivation of Science, Jadavpur, Kolkata 700 032; Department of Chemistry, University of ...

  2. The J–S model versus a non-ideal MHD theory

    Energy Technology Data Exchange (ETDEWEB)

    Franchi, Franca, E-mail: franca.franchi@unibo.it; Lazzari, Barbara, E-mail: barbara.lazzari@unibo.it; Nibbi, Roberta, E-mail: roberta.nibbi@unibo.it

    2015-07-17

    A new non-ideal electromagnetic interpretation of the J–S type viscoelastic model for polymeric fluids is given and a generalized resisto-elastic magnetohydrodynamic scenario for collisionless plasmas is proposed. The influence of the new theory on the incompressible transverse Alfvén waves is thoroughly investigated. - Highlights: • A non-ideal electromagnetic interpretation of the J–S type viscoelasticity is shown. • A generalized resisto-elastic magneto-hydrodynamic scenario for collision-less plasmas is proposed. • The shear-type magnetic waves are investigated.

  3. Rotor–stator contact dynamics using a non-ideal drive

    DEFF Research Database (Denmark)

    Lahriri, Said; Weber, H.I.Hans I.; Santos, I.F.Ilmar F.

    2012-01-01

    this for a conventional backup annular guide setup. It is reasonable to superpose an impact condition to the rub, where the rotor spin energy can be fully transformed into rotor lateral movements. Using a nonideal drive, i.e. an electric motor without any kind of velocity feedback control, it is even possible to stop...

  4. Electrochemical hydrogen pumping from high temperature plasma-chemical reactor involving H{sub 2}O/SO{sub 2} gas mixture

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Myoung Seok; Koo, Il Gyo; Kim, Jong Hoon; Lee, Woong Moo [Department of Chemistry and Division of Energy Systems Research, Ajou University, Suwon 443-749 (Korea)

    2009-01-15

    We demonstrate that the energy efficiency of hydrogen production by electrochemical hydrogen pumping out of a plasma-energized mixture of water vapor and sulfur dioxide (SO{sub 2}) can be greatly enhanced by raising the rector temperature above 800 C. The critical elements for this reactor design include the use of a microporous ceramic configuration for the discharge region, a bipolar electrode connecting the plasma reactor with the hydrogen pump, and a solid oxide membrane as the electrolyte of the pump. The amount of hydrogen produced per 100 joules of electrical energy consumed to operate the reactor at 850 C is 16 mL, which is more than twice the volume produced from the same reactor, operating at 100 C. The energy efficiency is almost 75% of that for the electrolysis of an H{sub 2}O/SO{sub 2} mixture. This type of plasma-assisted hydrogen pump opens up the possibility of producing hydrogen gas from water using the thermal energy from a nuclear reactor. (author)

  5. Optimising Reactive Control in non-ideal Efficiency Wave Energy Converters

    DEFF Research Database (Denmark)

    Strager, Thomas; Lopez, Pablo Fernandez; Giorgio, Giuseppe

    2014-01-01

    . These have been derived under the assumptions of monochromatic incoming waves and linear system behaviour. This allows to establish the power factor of a system with non-ideal efficiency. The locus of the optimal reactive control parameters is then studied and an alternative method of representation......When analytically optimising the control strategy in wave energy converters which use a point absorber, the efficiency aspect is generally neglected. The results presented in this paper provide an analytical expression for the mean harvested electrical power in non-ideal efficiency situations...... is developed to model the optimal control parameters. Ultimately we present a simple method of choosing optimal control parameters for any combination of efficiency and wave frequency....

  6. Nonlinear oscillations of a coupled autoparametrical system with ideal and nonideal sources of power

    Directory of Open Access Journals (Sweden)

    Sado Danuta

    2006-01-01

    Full Text Available An ideal and nonideal autoparametrical system excited by DC motor with unbalanced mass is presented in this work. The system consists of the body of mass M which is hung on a nonlinear spring with a nonlinear damper, and a pendulum of the length l and mass m mounted to the body of mass M. It is assumed that the motion of the pendulum is damped by nonlinear resistive forces. Vibrations of both models (ideal and nonideal are researched. Solutions for the system response are presented for specific values of the parameters of system and the energy transfer between modes of vibrations is studied. Next excited vibrations for both models have been examined analytically and numerically. Except different kinds of periodic vibrations, there may also appear chaotic vibrations.

  7. The phenomenon of runaway electrons in partially ionized non-ideal plasma

    Energy Technology Data Exchange (ETDEWEB)

    Ramazanov, T S; Turekhanova, K M [IETP, Al Farabi Kazakh National University, Tole Bi 96a, 050012 Almaty (Kazakhstan)], E-mail: kunduz@physics.kz

    2009-05-29

    The effect of runaway electrons in partially ionized hydrogen plasma is investigated on the basis of pseudopotential models. The conditions of runaway electrons were determined. Dependences of an electron free path on the plasma density and coupling parameter were obtained. It is shown that if the quantum-mechanical and screening effects in non-ideal partially ionized plasma are taken into consideration, the collision frequency curve for electrons has maxima and free path curves for electrons have minima.

  8. Thermodynamics of non-ideal QGP using Mayers cluster expansion method

    International Nuclear Information System (INIS)

    Prasanth, J.P; Simji, P.; Bannur, Vishnu M.

    2013-01-01

    The Quark gluon plasma (QGP) is the state in which the individual hadrons dissolve into a system of free (or almost free) quarks and gluons in strongly compressed system at high temperature. The present paper aims to calculate the critical temperature at which a non-ideal three quark plasma condenses into droplet of three quarks (i.e., into a liquid of baryons) using Mayers cluster expansion method

  9. Monitoring Streambed Scour/Deposition Under Nonideal Temperature Signal and Flood Conditions

    Science.gov (United States)

    DeWeese, Timothy; Tonina, Daniele; Luce, Charles

    2017-12-01

    Streambed erosion and deposition are fundamental geomorphic processes in riverbeds, and monitoring their evolution is important for ecological system management and in-stream infrastructure stability. Previous research showed proof of concept that analysis of paired temperature signals of stream and pore waters can simultaneously provide monitoring scour and deposition, stream sediment thermal regime, and seepage velocity information. However, it did not address challenges often associated with natural systems, including nonideal temperature variations (low-amplitude, nonsinusoidal signal, and vertical thermal gradients) and natural flooding conditions on monitoring scour and deposition processes over time. Here we addressed this knowledge gap by testing the proposed thermal scour-deposition chain (TSDC) methodology, with laboratory experiments to test the impact of nonideal temperature signals under a range of seepage velocities and with a field application during a pulse flood. Both analyses showed excellent match between surveyed and temperature-derived bed elevation changes even under very low temperature signal amplitudes (less than 1°C), nonideal signal shape (sawtooth shape), and strong and changing vertical thermal gradients (4°C/m). Root-mean-square errors on predicting the change in streambed elevations were comparable with the median grain size of the streambed sediment. Future research should focus on improved techniques for temperature signal phase and amplitude extractions, as well as TSDC applications over long periods spanning entire hydrographs.

  10. Evaluation of diffusion coefficients in multicomponent mixtures by means of the fluctuation theory

    DEFF Research Database (Denmark)

    Shapiro, Alexander

    2003-01-01

    We derive general expressions for diffusion coefficients in multicomponent non-ideal gas or liquid mixtures. The derivation is based on the general statistical theory of fluctuations around an equilibrium state. The matrix of diffusion coefficients is expressed in terms of the equilibrium...... characteristics. We demonstrate on several examples that the developed theory is in agreement with the established experimental facts and dependencies for the diffusion coefficients. (C) 2002 Elsevier Science B.V. All rights reserved....

  11. Thermodynamic study of (anthracene + phenanthrene) solid state mixtures.

    Science.gov (United States)

    Rice, James W; Fu, Jinxia; Sandström, Emma; Ditto, Jenna C; Suuberg, Eric M

    2015-11-01

    Polycyclic aromatic hydrocarbons (PAH) are common components of many materials, such as petroleum and various types of tars. They are generally present in mixtures, occurring both naturally and as byproducts of fuel processing operations. It is important to understand the thermodynamic properties of such mixtures in order to understand better and predict their behavior ( i.e. , fate and transport) in the environment and in industrial operations. To characterize better the thermodynamic behavior of PAH mixtures, the phase behavior of a binary (anthracene + phenanthrene) system was studied by differential scanning calorimetry, X-ray diffraction, and the Knudsen effusion technique. Mixtures of (anthracene + phenanthrene) exhibit non-ideal mixture behavior. They form a lower-melting, phenanthrene-rich phase with an initial melting temperature of 372 K (identical to the melting temperature of pure phenanthrene) and a vapor pressure of roughly ln P /Pa = -2.38. The phenanthrene-rich phase coexists with an anthracene-rich phase when the mole fraction of phenanthrene ( x P ) in the mixture is less than or equal to 0.80. Mixtures initially at x P = 0.90 consist entirely of the phenanthrene-rich phase and sublime at nearly constant vapor pressure and composition, consistent with azeotrope-like behavior. Quasi-azeotropy was also observed for very high-content anthracene mixtures (2.5 < x P < 5) indicating that anthracene may accommodate very low levels of phenanthrene in its crystal structure.

  12. Numerical modelling of underwater detonation of non-ideal condensed-phase explosives

    Science.gov (United States)

    Schoch, Stefan; Nikiforakis, Nikolaos

    2015-01-01

    The interest in underwater detonation tests originated from the military, since the expansion and subsequent collapse of the explosive bubble can cause considerable damage to surrounding structures or vessels. In military applications, the explosive is typically represented as a pre-burned material under high pressure, a reasonable assumption due to the short reaction zone lengths, and complete detonation of the unreacted explosive. Hence, numerical simulations of underwater detonation tests have been primarily concerned with the prediction of target loading and the damage incurred rather than the accurate modelling of the underwater detonation process. The mining industry in contrast has adopted the underwater detonation test as a means to experimentally characterise the energy output of their highly non-ideal explosives depending on explosive type and charge configuration. This characterisation requires a good understanding of how the charge shape, pond topography, charge depth, and additional charge confinement affect the energy release, some of which can be successfully quantified with the support of accurate numerical simulations. In this work, we propose a numerical framework which is able to capture the non-ideal explosive behaviour and in addition is capable of capturing both length scales: the reaction zone and the pond domain. The length scale problem is overcome with adaptive mesh refinement, which, along with the explosive model, is validated against experimental data of various TNT underwater detonations. The variety of detonation and bubble behaviour observed in non-ideal detonations is demonstrated in a parameter study over the reactivity of TNT. A representative underwater mining test containing an ammonium-nitrate fuel-oil ratestick charge is carried out to demonstrate that the presented method can be readily applied alongside experimental underwater detonation tests.

  13. High Order Filter Methods for the Non-ideal Compressible MHD Equations

    Science.gov (United States)

    Yee, H. C.; Sjoegreen, Bjoern

    2003-01-01

    The generalization of a class of low-dissipative high order filter finite difference methods for long time wave propagation of shock/turbulence/combustion compressible viscous gas dynamic flows to compressible MHD equations for structured curvilinear grids has been achieved. The new scheme is shown to provide a natural and efficient way for the minimization of the divergence of the magnetic field numerical error. Standard divergence cleaning is not required by the present filter approach. For certain non-ideal MHD test cases, divergence free preservation of the magnetic fields has been achieved.

  14. Phase shift effects for fluid conveying pipes with non-ideal supports

    DEFF Research Database (Denmark)

    Dahl, Jonas; Thomsen, Jon Juel

    2008-01-01

    Vibrations of a fluid-conveying pipe with non-ideal supports are investigated with respect to phase shift effects. A numerical Galerkin approach is developed for this general problem, and the use of it exemplified with a investigation of phase shift effects from rotational damping at supports...... of a simply supported pipe. It is found that asymmetric viscous rotational damping at supports gives rise to phase shifts along the pipe which cannot be distinguished from phase shift from mass flow. This is of interest, e.g., for the development and troubleshooting of Coriolis flow meters....

  15. Performance of non-ideal OT-MRC with co-channel interference

    KAUST Repository

    Radaydeh, Redha Mahmoud Mesleh

    2010-12-01

    This paper studies the effect of non-ideal estimation of channel state information (CSI) on the performance of output-threshold maximal-ratio combining (OT-MRC) diversity scheme in the presence of co-channel interference as well as white noise. The channel fading envelopes are assumed to follow slowly varying flat Rayleigh model. New closed-form expressions for the combined signal-to-interference-plus-noise ratio (SINR) distribution and outage probability performance are presented. Performance comparisons between the conventional MRC and OT-MRC for the system model described above are provided. © 2010 IEEE.

  16. Dark energy from cosmological fluids obeying a Shan-Chen non-ideal equation of state

    OpenAIRE

    Bini, Donato; Geralico, Andrea; Gregoris, Daniele; Succi, Sauro

    2014-01-01

    We consider a Friedmann-Robertson-Walker universe with a fluid source obeying a nonideal equation of state with ‘‘asymptotic freedom,’’ namely ideal gas behavior (pressure changes directly proportional to density changes) both at low and high density regimes, following a fluid dynamical model due to Shan and Chen. It is shown that, starting from an ordinary energy density component, such fluids naturally evolve towards a universe with a substantial ‘‘dark energy’’ component at the present tim...

  17. Contact interaction of a circular stamp with a layer under nonideal thermal contact.

    Directory of Open Access Journals (Sweden)

    B.S. Okrepkyi

    2011-12-01

    Full Text Available Solution of the axis-symmetric contact task of thermo-elasticity of the hot cylinder circular punch stress on the elastic isotropic layer taking into account a non-ideal heat contact between punch and layer is built. Formulas for determination of the temperature field and normal stress in the contact area are obtained. The effect of the contact elasticity on the temperature and normal stress distribution is investigated. Investigation was made on the influence of the contact conductivity on distributing of the temperature fields and normal stress in the area of contact of two bodies.

  18. Comparison of non-ideal solution theories for multi-solute solutions in cryobiology and tabulation of required coefficients.

    Science.gov (United States)

    Zielinski, Michal W; McGann, Locksley E; Nychka, John A; Elliott, Janet A W

    2014-10-01

    Thermodynamic solution theories allow the prediction of chemical potentials in solutions of known composition. In cryobiology, such models are a critical component of many mathematical models that are used to simulate the biophysical processes occurring in cells and tissues during cryopreservation. A number of solution theories, both thermodynamically ideal and non-ideal, have been proposed for use with cryobiological solutions. In this work, we have evaluated two non-ideal solution theories for predicting water chemical potential (i.e. osmolality) in multi-solute solutions relevant to cryobiology: the Elliott et al. form of the multi-solute osmotic virial equation, and the Kleinhans and Mazur freezing point summation model. These two solution theories require fitting to only single-solute data, although they can make predictions in multi-solute solutions. The predictions of these non-ideal solution theories were compared to predictions made using ideal dilute assumptions and to available literature multi-solute experimental osmometric data. A single, consistent set of literature single-solute solution data was used to fit for the required solute-specific coefficients for each of the non-ideal models. Our results indicate that the two non-ideal solution theories have similar overall performance, and both give more accurate predictions than ideal models. These results can be used to select between the non-ideal models for a specific multi-solute solution, and the updated coefficients provided in this work can be used to make the desired predictions. Copyright © 2014 The Authors. Published by Elsevier Inc. All rights reserved.

  19. Pulsatile Gating of Giant Vesicles Containing Macromolecular Crowding Agents Induced by Colligative Nonideality.

    Science.gov (United States)

    Su, Wan-Chih; Gettel, Douglas L; Chabanon, Morgan; Rangamani, Padmini; Parikh, Atul N

    2018-01-17

    The ability of large macromolecules to exhibit nontrivial deviations in colligative properties of their aqueous solutions is well-appreciated in polymer physics. Here, we show that this colligative nonideality subjects giant lipid vesicles containing inert macromolecular crowding agents to osmotic pressure differentials when bathed in small-molecule osmolytes at comparable concentrations. The ensuing influx of water across the semipermeable membrane induces characteristic swell-burst cycles: here, cyclical and damped oscillations in size, tension, and membrane phase separation occur en route to equilibration. Mediated by synchronized formation of transient pores, these cycles orchestrate pulsewise ejection of macromolecules from the vesicular interior reducing the osmotic differential in a stepwise manner. These experimental findings are fully corroborated by a theoretical model derived by explicitly incorporating the contributions of the solution viscosity, solute diffusivity, and the colligative nonideality of the osmotic pressure in a previously reported continuum description. Simulations based on this model account for the differences in the details of the noncolligatively induced swell-burst cycles, including numbers and periods of the repeating cycles, as well as pore lifetimes. Taken together, our observations recapitulate behaviors of vesicles and red blood cells experiencing sudden osmotic shocks due to large (hundreds of osmolars) differences in the concentrations of small molecule osmolytes and link intravesicular macromolecular crowding with membrane remodeling. They further suggest that any tendency for spontaneous overcrowding in single giant vesicles is opposed by osmotic stresses and requires independent specific interactions, such as associative chemical interactions or those between the crowders and the membrane boundary.

  20. Modeling reactive transport in non-ideal aqueous-solid solution system

    Energy Technology Data Exchange (ETDEWEB)

    Shao, Haibing, E-mail: haibing.shao@ufz.de [UFZ-Helmholtz Centre for Environmental Research, Department Environmental Informatics, Permoserstrasse 15, 04318 Leipzig (Germany)] [Applied Environmental System Analysis, TU Dresden, Helmholtzstrasse 10, 01069 Dresden (Germany); Dmytrieva, Svitlana V. [SSC Technocentre, Nauky Prosp. 46, 03650 Kyiv (Ukraine)] [Laboratory for Waste Management, Paul Scherrer Institute, 5232 Villigen PSI (Switzerland); Kolditz, Olaf [UFZ-Helmholtz Centre for Environmental Research, Department Environmental Informatics, Permoserstrasse 15, 04318 Leipzig (Germany)] [Applied Environmental System Analysis, TU Dresden, Helmholtzstrasse 10, 01069 Dresden (Germany); Kulik, Dmitrii A.; Pfingsten, Wilfried; Kosakowski, Georg [Laboratory for Waste Management, Paul Scherrer Institute, 5232 Villigen PSI (Switzerland)

    2009-07-15

    The numerical simulation of reactive mass transport processes in complex geochemical environments is an important tool for the performance assessment of future waste repositories. A new combination of the multi-component mass transport code GeoSys/RockFlow and the Gibbs Energy Minimization (GEM) equilibrium solver GEM-Selektor is used to calculate the accurate equilibrium of multiple non-ideal solid solutions which are important for the immobilization of radionuclides such as Ra. The coupled code is verified by a widely used benchmark of dissolution-precipitation in a calcite-dolomite system. A more complex application shown in this paper is the transport of Ra in the near-field of a nuclear waste repository. Depending on the initial inventories of Sr, Ba and sulfate, non-ideal sulfate and carbonate solid solutions can fix mobile Ra cations. Due to the complex geochemical interactions, the reactive transport simulations can describe the migration of Ra in a much more realistic way than using the traditional linear K{sub D} approach only.

  1. Multi-objective optimization of Stirling engine using non-ideal adiabatic method

    International Nuclear Information System (INIS)

    Toghyani, Somayeh; Kasaeian, Alibakhsh; Ahmadi, Mohammad H.

    2014-01-01

    Highlights: • A multi-objective optimization is carried out for a Stirling engine. • The methods of TOPSIS, Fuzzy, and LINMAP are compared with each other in aspect of optimization. • The results are compared with the previous works for checking the model improvement. • A proper improvement is observed using TOPSIS when comparing with the others. - Abstract: In the recent years, remarkable attention is drawn to Stirling engine due to noticeable advantages, for instance a lot of resources such as biomass, fossil fuels and solar energy can be applied as heat source. Great numbers of studies are conducted on Stirling engines and non-ideal adiabatic method is one of them. In the present study, the efficiency and the power loss due to pressure drop into the heat exchangers are optimized for a Stirling system using non-ideal adiabatic analysis and the second-version Non-dominated Sorting Genetic Algorithm. The optimized answers are chosen from the results using three decision-making methods. The applied methods were compared at last and the best results were obtained for the technique for order preference by similarity to ideal solution decision making method

  2. Performance of active feedforward control systems in non-ideal, synthesized diffuse sound fields.

    Science.gov (United States)

    Misol, Malte; Bloch, Christian; Monner, Hans Peter; Sinapius, Michael

    2014-04-01

    The acoustic performance of passive or active panel structures is usually tested in sound transmission loss facilities. A reverberant sending room, equipped with one or a number of independent sound sources, is used to generate a diffuse sound field excitation which acts as a disturbance source on the structure under investigation. The spatial correlation and coherence of such a synthesized non-ideal diffuse-sound-field excitation, however, might deviate significantly from the ideal case. This has consequences for the operation of an active feedforward control system which heavily relies on the acquisition of coherent disturbance source information. This work, therefore, evaluates the spatial correlation and coherence of ideal and non-ideal diffuse sound fields and considers the implications on the performance of a feedforward control system. The system under consideration is an aircraft-typical double panel system, equipped with an active sidewall panel (lining), which is realized in a transmission loss facility. Experimental results for different numbers of sound sources in the reverberation room are compared to simulation results of a comparable generic double panel system excited by an ideal diffuse sound field. It is shown that the number of statistically independent noise sources acting on the primary structure of the double panel system depends not only on the type of diffuse sound field but also on the sample lengths of the processed signals. The experimental results show that the number of reference sensors required for a defined control performance exhibits an inverse relationship to control filter length.

  3. A complete equation of state for non-ideal condensed phase explosives

    Science.gov (United States)

    Wilkinson, S. D.; Braithwaite, M.; Nikiforakis, N.; Michael, L.

    2017-12-01

    The objective of this work is to improve the robustness and accuracy of numerical simulations of both ideal and non-ideal explosives by introducing temperature dependence in mechanical equations of state for reactants and products. To this end, we modify existing mechanical equations of state to appropriately approximate the temperature in the reaction zone. Mechanical equations of state of the Mie-Grüneisen form are developed with extensions, which allow the temperature to be evaluated appropriately and the temperature equilibrium condition to be applied robustly. Furthermore, the snow plow model is used to capture the effect of porosity on the reactant equation of state. We apply the methodology to predict the velocity of compliantly confined detonation waves. Once reaction rates are calibrated for unconfined detonation velocities, simulations of confined rate sticks and slabs are performed, and the experimental detonation velocities are matched without further parameter alteration, demonstrating the predictive capability of our simulations. We apply the same methodology to both ideal (PBX9502, a high explosive with principal ingredient TATB) and non-ideal (EM120D, an ANE or ammonium nitrate based emulsion) explosives.

  4. Impact of coal structural heterogeneity on the nonideal sorption of organic contaminants.

    Science.gov (United States)

    Shi, Xin; Fu, Heyun; Li, Yuan; Mao, Jingdong; Zheng, Shourong; Zhu, Dongqiang

    2011-06-01

    Carbonaceous geosorbents (black carbon, coal, and humin/kerogen) play a primary role in the nonideal sorption (isotherm nonlinearity, hysteresis, and multiphasic kinetics) of hydrophobic organic chemicals by soils and sediments. The present study investigated the impact of coal structural heterogeneity on sorption/desorption of two model monoaromatic compounds (1,3-dichlorobenzene and 1,3-dinitrobenzene). Due to the higher degree of aromaticity and condensation, anthracite showed stronger sorption affinity and nonlinearity and slower sorption kinetics than lignite. Removal of humic substances by alkali extraction and/or mineral fraction by acidification did not much affect organic carbon-normalized sorption coefficient to the coal, suggesting nearly complete accessibility of adsorption sites on the condensed organic carbon. However, the treatments greatly increased sorption kinetics and meanwhile alleviated hysteresis of 1,3-dinitrobenzene, as compared with the original lignite. These observations were attributed to the enhanced exposure of high-energy adsorption sites on the condensed organic carbon after exfoliating the surface coverage by humic substances and minerals. An empirical biphasic pseudo-second-order model consisting of a fast sorption phase and a slow sorption phase adequately quantified the overall sorption kinetics for the coal sorbents. The results indicated that the condensed organic carbon, in combination with other structural components, controls the nonideal sorption of unburned coal. Copyright © 2011 SETAC.

  5. Stochastic line motion and stochastic flux conservation for nonideal hydromagnetic models

    International Nuclear Information System (INIS)

    Eyink, Gregory L.

    2009-01-01

    We prove that smooth solutions of nonideal (viscous and resistive) incompressible magnetohydrodynamic (MHD) equations satisfy a stochastic law of flux conservation. This property implies that the magnetic flux through a surface is equal to the average of the magnetic fluxes through an ensemble of surfaces advected backward in time by the plasma velocity perturbed with a random white noise. Our result is an analog of the well-known Alfven theorem of ideal MHD and is valid for any value of the magnetic Prandtl number. A second stochastic conservation law is shown to hold at unit Prandtl number, a random version of the generalized Kelvin theorem derived by Bekenstein and Oron for ideal MHD. These stochastic conservation laws are not only shown to be consequences of the nonideal MHD equations but are proved in fact to be equivalent to those equations. We derive similar results for two more refined hydromagnetic models, Hall MHD and the two-fluid plasma model, still assuming incompressible velocities and isotropic transport coefficients. Finally, we use these results to discuss briefly the infinite-Reynolds-number limit of hydromagnetic turbulence and to support the conjecture that flux conservation remains stochastic in that limit.

  6. The collapse of a molecular cloud core to stellar densities using radiation non-ideal magnetohydrodynamics

    Science.gov (United States)

    Wurster, James; Bate, Matthew R.; Price, Daniel J.

    2018-04-01

    We present results from radiation non-ideal magnetohydrodynamics (MHD) calculations that follow the collapse of rotating, magnetized, molecular cloud cores to stellar densities. These are the first such calculations to include all three non-ideal effects: ambipolar diffusion, Ohmic resistivity, and the Hall effect. We employ an ionization model in which cosmic ray ionization dominates at low temperatures and thermal ionization takes over at high temperatures. We explore the effects of varying the cosmic ray ionization rate from ζcr = 10-10 to 10-16 s-1. Models with ionization rates ≳10-12 s-1 produce results that are indistinguishable from ideal MHD. Decreasing the cosmic ray ionization rate extends the lifetime of the first hydrostatic core up to a factor of 2, but the lifetimes are still substantially shorter than those obtained without magnetic fields. Outflows from the first hydrostatic core phase are launched in all models, but the outflows become broader and slower as the ionization rate is reduced. The outflow morphology following stellar core formation is complex and strongly dependent on the cosmic ray ionization rate. Calculations with high ionization rates quickly produce a fast (≈14 km s-1) bipolar outflow that is distinct from the first core outflow, but with the lowest ionization rate, a slower (≈3-4 km s-1) conical outflow develops gradually and seamlessly merges into the first core outflow.

  7. Continuous time sigma delta ADC design and non-idealities analysis

    International Nuclear Information System (INIS)

    Yuan Jun; Chen Zhenhai; Yang Yintang; Zhang Zhaofeng; Wu Jun; Wang Chao; Qian Wenrong

    2011-01-01

    A wide bandwidth continuous time sigma delta ADC is implemented in 130 nm CMOS. A detailed non-idealities analysis (excess loop delay, clock jitter, finite gain and GBW, comparator offset and DAC mismatch) is performed developed in Matlab/Simulink. This design is targeted for wide bandwidth applications such as video or wireless base-stations. Athird-order continuous time sigma delta modulator comprises a third-order RC operational-amplifier-based loop filter and 3-bit internal quantizer operated at 512 MHz clock frequency. The sigma delta ADC achieves 60 dB SNR and 59.3 dB SNDR over a 16-MHz signal band at an OSR of 16. The power consumption of the CT sigma delta modulator is 22 mW from the 1.2-V supply. (semiconductor integrated circuits)

  8. Adolescent self-injurers: Comparing non-ideators, suicide ideators, and suicide attempters.

    Science.gov (United States)

    Stewart, Jeremy G; Esposito, Erika C; Glenn, Catherine R; Gilman, Stephen E; Pridgen, Bryan; Gold, Joseph; Auerbach, Randy P

    2017-01-01

    Adolescent non-suicidal self-injury (NSSI) and suicidality are serious health concerns; however, factors that contribute to the transition from NSSI to suicide ideation and suicide attempts are unclear. To address this gap, we investigated whether demographic characteristics, child maltreatment, and psychiatric factors are associated with the level suicidality among adolescents with a history of self-injury. Participants were three groups of adolescent inpatient self-injurers (n = 397, 317 female), aged 13-18 years (M = 15.44, SD = 1.36): (a) non-ideators (n = 96; no current suicide ideation and no lifetime suicide attempts), (b) suicide ideators (n = 149; current ideation and no lifetime attempts), and (c) suicide attempters (n = 152; current ideation and at least one lifetime attempt). Participants completed interviews assessing psychiatric diagnoses, suicidality, and NSSI characteristics, as well as questionnaires on childhood trauma, psychiatric symptoms, and risky behavior engagement. Depression severity was associated with greater odds being a suicide ideator (p Suicide attempters used more NSSI methods and reported greater risky behavior engagement than non-ideators (p = 0.03, OR = 1.29 and p = 0.03, OR = 1.06, respectively) and ideators (p = 0.015, OR = 1.25 and p = 0.04, OR = 1.05, respectively); attempters used more severe NSSI methods (e.g., burning). Our results identify a wide range of risk markers for increasing lethality in a sample at high risk for suicide mortality; future research is needed to refine risk assessments for adolescent self-injurers and determine the clinical utility of using risk markers for screening and intervention. Copyright © 2016 Elsevier Ltd. All rights reserved.

  9. Redundant imprinting of information in nonideal environments: Objective reality via a noisy channel

    International Nuclear Information System (INIS)

    Zwolak, Michael; Quan, H. T.; Zurek, Wojciech H.

    2010-01-01

    Quantum Darwinism provides an information-theoretic framework for the emergence of the objective, classical world from the quantum substrate. The key to this emergence is the proliferation of redundant information throughout the environment where observers can then intercept it. We study this process for a purely decohering interaction when the environment, E, is in a nonideal (e.g., mixed) initial state. In the case of good decoherence, that is, after the pointer states have been unambiguously selected, the mutual information between the system, S, and an environment fragment, F, is given solely by F's entropy increase. This demonstrates that the environment's capacity for recording the state of S is directly related to its ability to increase its entropy. Environments that remain nearly invariant under the interaction with S, either because they have a large initial entropy or a misaligned initial state, therefore have a diminished ability to acquire information. To elucidate the concept of good decoherence, we show that, when decoherence is not complete, the deviation of the mutual information from F's entropy change is quantified by the quantum discord, i.e., the excess mutual information between S and F is information regarding the initial coherence between pointer states of S. In addition to illustrating these results with a single-qubit system interacting with a multiqubit environment, we find scaling relations for the redundancy of information acquired by the environment that display a universal behavior independent of the initial state of S. Our results demonstrate that Quantum Darwinism is robust with respect to nonideal initial states of the environment: the environment almost always acquires redundant information about the system but its rate of acquisition can be reduced.

  10. Local invariants in non-ideal flows of neutral fluids and two-fluid plasmas

    Science.gov (United States)

    Zhu, Jian-Zhou

    2018-03-01

    The main objective is the locally invariant geometric object of any (magneto-)fluid dynamics with forcing and damping (nonideal), while more attention is paid to the untouched dynamical properties of two-fluid fashion. Specifically, local structures, beyond the well-known "frozen-in" to the barotropic flows of the generalized vorticities, of the two-fluid model of plasma flows are presented. More general non-barotropic situations are also considered. A modified Euler equation [T. Tao, "Finite time blowup for Lagrangian modifications of the three-dimensional Euler equation," Ann. PDE 2, 9 (2016)] is also accordingly analyzed and remarked from the angle of view of the two-fluid model, with emphasis on the local structures. The local constraints of high-order differential forms such as helicity, among others, find simple formulation for possible practices in modeling the dynamics. Thus, the Cauchy invariants equation [N. Besse and U. Frisch, "Geometric formulation of the Cauchy invariants for incompressible Euler flow in flat and curved spaces," J. Fluid Mech. 825, 412 (2017)] may be enabled to find applications in non-ideal flows. Some formal examples are offered to demonstrate the calculations, and particularly interestingly the two-dimensional-three-component (2D3C) or the 2D passive scalar problem presents that a locally invariant Θ = 2θζ, with θ and ζ being, respectively, the scalar value of the "vertical velocity" (or the passive scalar) and the "vertical vorticity," may be used as if it were the spatial density of the globally invariant helicity, providing a Lagrangian prescription to control the latter in some situations of studying its physical effects in rapidly rotating flows (ubiquitous in atmosphere of astrophysical objects) with marked 2D3C vortical modes or in purely 2D passive scalars.

  11. The phase behavior of a hard sphere chain model of a binary n-alkane mixture

    International Nuclear Information System (INIS)

    Malanoski, A. P.; Monson, P. A.

    2000-01-01

    Monte Carlo computer simulations have been used to study the solid and fluid phase properties as well as phase equilibrium in a flexible, united atom, hard sphere chain model of n-heptane/n-octane mixtures. We describe a methodology for calculating the chemical potentials for the components in the mixture based on a technique used previously for atomic mixtures. The mixture was found to conform accurately to ideal solution behavior in the fluid phase. However, much greater nonidealities were seen in the solid phase. Phase equilibrium calculations indicate a phase diagram with solid-fluid phase equilibrium and a eutectic point. The components are only miscible in the solid phase for dilute solutions of the shorter chains in the longer chains. (c) 2000 American Institute of Physics

  12. DC parameter extraction of equivalent circuit model in InGaAsSb heterojunction bipolar transistors including non-ideal effects in the base region

    Science.gov (United States)

    Chang, Yang-Hua; Cheng, Zong-Tai

    2011-07-01

    This paper presents the DC parameter extraction of the equivalent circuit model in an InP-InGaAsSb double heterojunction bipolar transistor (HBT). The non-ideal collector current is modeled by a non-ideal doping distribution in the base region. Then several consequent non-ideal effects, which have always been neglected in typical HBTs, are studied using Medici device simulator. Moreover, the associated DC parameters of VBIC model are extracted accordingly. The equivalent circuit model is in good agreement with the measured data in I C- V CE characteristics.

  13. Toxic fumes from explosives: ammonium nitrate-fuel oil mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Chaiken, R.F.; Cook, E.B.; Ruhe, T.C.

    1974-01-01

    The Bureau of Mines has carried out experimental and theoretical studies with prilled and pulverized ammonium nitrate-fuel oil (AN-FO) mixtures containing varying amounts of fuel oil in an attempt to quantify the effects of stoichiometric composition, nonideal detonation behavior, and expansion volume on the production of CO, NO, and NO/sub 2/ fumes. Experimental fume measurements were obtained in the Bureau's large closed gallery facility (7.2 x 10/sup 4/ liter expansion chamber) and in the standard Crawshaw-Jones apparatus (90-liter expansion chamber) using a prepackaged charge configuration containing about 450 g of explosives. The theoretical calculation of toxic fumes was achieved with an equilibrium detonation code called TIGER. Contrary to initial expectations, the NO/sub x/ (= NO + NO/sub 2/) fumes from the large gallery test were found to be in essential agreement with the Crawshaw-Jones results. It was also concluded that TIGER calculations offer a good approach to the prediction of toxic fumes; there is a basic problem in extrapolating laboratory measurements of CO fumes to mine conditions, this being due to postdetonation oxidation of CO to CO/sub 2/; and the detonation velocity decay rate of an explosive is a useful experimental parameter for correlating toxic fumes production with nonideal detonation behavior.

  14. Accounting for thermodynamic non-ideality in the Guinier region of small-angle scattering data of proteins.

    Science.gov (United States)

    Scott, David J

    2016-12-01

    Hydrodynamic studies of the solution properties of proteins and other biological macromolecules are often hard to interpret when the sample is present at a reasonably concentrated solution. The reason for this is that solutions exhibit deviations from ideal behaviour which is manifested as thermodynamic non-ideality. The range of concentrations at which this behaviour typically is exhibited is as low as 1-2 mg/ml, well within the range of concentrations used for their analysis by techniques such as small-angle scattering. Here we discuss thermodynamic non-ideality used previously used in the context of light scattering and sedimentation equilibrium analytical ultracentrifugation and apply it to the Guinier region of small-angle scattering data. The results show that there is a complementarity between the radially averaged structure factor derived from small-angle X-ray scattering/small-angle neutron scattering studies and the second virial coefficient derived from sedimentation equilibrium analytical ultracentrifugation experiments.

  15. Modelling of an anaerobic plug-flow reactor. Process analysis and evaluation approaches with non-ideal mixing considerations.

    Science.gov (United States)

    Donoso-Bravo, Andrés; Sadino-Riquelme, Constanza; Gómez, Daniel; Segura, Camilo; Valdebenito, Emky; Hansen, Felipe

    2018-03-29

    This study shows the implementation of the Anaerobic Digestion Model (ADM1) in an anaerobic plug-flow reactor (PFR) with two approaches based on the use of consecutive continuous stirred tank reactors (CSTR) connected in serie for considering non-ideal mixing. The two-region (TR) model splits each CSTR into two regions, while the particulate retention (PR) model adds a retention parameter. The models were calibrated and validated based on experimental data from a bench-scale reactor treating cow manure. The PFR conventional model slightly outperformed the non-ideal mixing approaches. However, the PR model showed an increase in biomass retention time treating high solid content substrate. Biogas production was not sensitive to variations of the mixing parameters. The liquid fraction content was better represented by the PR model than the PFR and TR models. The study shows how reactor modelling is useful for monitoring and supervising biogas plants. Copyright © 2018 Elsevier Ltd. All rights reserved.

  16. Finite element limit loads for non-idealized through-wall cracks in thick-walled pipe

    International Nuclear Information System (INIS)

    Shim, Do-Jun; Han, Tae-Song; Huh, Nam-Su

    2013-01-01

    Highlights: • The lower bound bulging factor of thin-walled pipe can be used for thick-walled pipe. • The limit loads are proposed for thick-walled, transition through-wall cracked pipe. • The correction factors are proposed for estimating limit loads of transition cracks. • The limit loads of short transition cracks are similar to those of idealized cracks. - Abstract: The present paper provides plastic limit loads for non-idealized through-wall cracks in thick-walled pipe. These solutions are based on detailed 3-dimensional finite element (FE) analyses which can be used for structural integrity assessment of nuclear piping. To cover a practical range of interest, the geometric variables and loading conditions affecting the plastic limit loads of thick-walled pipe with non-idealized through-wall cracks were systematically varied. In terms of crack orientation, both circumferential and axial through-wall cracks were considered. As for loading conditions, axial tension, global bending, and internal pressure were considered for circumferential cracks, whereas only internal pressure was considered for axial cracks. Furthermore, the values of geometric factor representing shape characteristics of non-idealized through-wall cracks were also systematically varied. In order to provide confidence in the present FE analyses results, plastic limit loads of un-cracked, thick-walled pipe resulting from the present FE analyses were compared with the theoretical solutions. Finally, correction factors to the idealized through-wall crack solutions were developed to determine the plastic limit loads of non-idealized through-wall cracks in thick-walled pipe

  17. Propagation of a cylindrical shock wave in a rotational axisymmetric isothermal flow of a non-ideal gas in magnetogasdynamics

    Directory of Open Access Journals (Sweden)

    G. Nath

    2012-12-01

    Full Text Available Self-similar solutions are obtained for unsteady, one-dimensional isothermal flow behind a shock wave in a rotational axisymmetric non-ideal gas in the presence of an azimuthal magnetic field. The shock wave is driven out by a piston moving with time according to power law. The fluid velocities and the azimuthal magnetic field in the ambient medium are assumed to be varying and obeying a power law. The density of the ambient medium is assumed to be constant. The gas is assumed to be non-ideal having infinite electrical conductivity and the angular velocity of the ambient medium is assumed to be decreasing as the distance from the axis increases. It is expected that such an angular velocity may occur in the atmospheres of rotating planets and stars. The effects of the non-idealness of the gas and the Alfven-Mach number on the flow-field are obtained. It is shown that the presence of azimuthal magnetic field and the rotation of the medium has decaying effect on the shock wave. Also, a comparison is made between rotating and non-rotating cases.

  18. Decomposition of the Equations of Motion in the Analysis of Dynamics of a 3-DOF Nonideal System

    Directory of Open Access Journals (Sweden)

    Jan Awrejcewicz

    2014-01-01

    Full Text Available The dynamic response of a nonlinear system with three degrees of freedom, which is excited by nonideal excitation, is investigated. In the considered system the role of a nonideal source is played by a direct current motor, where the central axis of the rotor is not coincident with the axis of rotation. This translation generates a torque whose magnitude depends on the angular velocity. During the system operation a general coordinate assigned to the nonideal source grows rapidly as a result of rotation. We propose the decomposition of the equations of motion in such a way to extract the solution which is directly related to the rotation of an unbalanced rotor. The remaining part of the solution describes pure oscillation depending on the dynamical behaviour of the whole system. The decomposed equations are solved numerically. The influence of selected system parameters on the rotor vibration is examined. The presented approach can be applied to separate vibration and rotation of motions in many other engineering systems.

  19. A Thermodynamically-Consistent Non-Ideal Stochastic Hard-Sphere Fluid

    Energy Technology Data Exchange (ETDEWEB)

    Donev, A; Alder, B J; Garcia, A L

    2009-08-03

    A grid-free variant of the Direct Simulation Monte Carlo (DSMC) method is proposed, named the Isotropic DSMC (I-DSMC) method, that is suitable for simulating collision-dominated dense fluid flows. The I-DSMC algorithm eliminates all grid artifacts from the traditional DSMC algorithm and is Galilean invariant and microscopically isotropic. The stochastic collision rules in I-DSMC are modified to introduce a non-ideal structure factor that gives consistent compressibility, as first proposed in [Phys. Rev. Lett. 101:075902 (2008)]. The resulting Stochastic Hard Sphere Dynamics (SHSD) fluid is empirically shown to be thermodynamically identical to a deterministic Hamiltonian system of penetrable spheres interacting with a linear core pair potential, well-described by the hypernetted chain (HNC) approximation. We develop a kinetic theory for the SHSD fluid to obtain estimates for the transport coefficients that are in excellent agreement with particle simulations over a wide range of densities and collision rates. The fluctuating hydrodynamic behavior of the SHSD fluid is verified by comparing its dynamic structure factor against theory based on the Landau-Lifshitz Navier-Stokes equations. We also study the Brownian motion of a nano-particle suspended in an SHSD fluid and find a long-time power-law tail in its velocity autocorrelation function consistent with hydrodynamic theory and molecular dynamics calculations.

  20. Adaptive Numerical Dissipation Control in High Order Schemes for Multi-D Non-Ideal MHD

    Science.gov (United States)

    Yee, H. C.; Sjoegreen, B.

    2005-01-01

    The required type and amount of numerical dissipation/filter to accurately resolve all relevant multiscales of complex MHD unsteady high-speed shock/shear/turbulence/combustion problems are not only physical problem dependent, but also vary from one flow region to another. In addition, proper and efficient control of the divergence of the magnetic field (Div(B)) numerical error for high order shock-capturing methods poses extra requirements for the considered type of CPU intensive computations. The goal is to extend our adaptive numerical dissipation control in high order filter schemes and our new divergence-free methods for ideal MHD to non-ideal MHD that include viscosity and resistivity. The key idea consists of automatic detection of different flow features as distinct sensors to signal the appropriate type and amount of numerical dissipation/filter where needed and leave the rest of the region free from numerical dissipation contamination. These scheme-independent detectors are capable of distinguishing shocks/shears, flame sheets, turbulent fluctuations and spurious high-frequency oscillations. The detection algorithm is based on an artificial compression method (ACM) (for shocks/shears), and redundant multiresolution wavelets (WAV) (for the above types of flow feature). These filters also provide a natural and efficient way for the minimization of Div(B) numerical error.

  1. Nonideal anion displacement, band gap variation, and valence band splitting in Cu-In-Se compounds

    International Nuclear Information System (INIS)

    Reena Philip, Rachel; Pradeep, B.

    2005-01-01

    Polycrystalline thin films of ternary chalcopyrite CuInSe 2 and defect compounds CuIn 3 Se 5 and CuIn 5 Se 8 are prepared in vacuum by three-source coevaporation method. Structural and optical characterizations of the films are done using X-ray diffraction (XRD), energy-dispersive X-ray analysis (EDAX), and optical absorbance spectra measurements. With variation in the composition of CuInSe 2 , a change over from p-type to n-type conductivity is observed (as noted by the hot probe method). The deformation parameters and the anion displacements are calculated from the X-ray diffraction data, and the cation-anion bond lengths are deduced. The dependence of band gap variation on nonideal anion displacement in the ternary compounds and the effect of Se-p-Cu-d repulsion on band gap are studied. The threefold optical structure observed in the fundamental absorption region of the absorption spectra is analysed to extract the valence band splitting parameters. Hopfields quasi-cubic model adapted for chalcopyrites with tetragonal deformation is used to determine the crystal field splittings and spin orbit splittings, and the linear hybridization model is used to calculate the percentage of d-orbital and p-orbital contribution to hybridization in the compounds under consideration

  2. Spectral Analysis of Non-ideal MRI Modes: The Effect of Hall Diffusion

    Energy Technology Data Exchange (ETDEWEB)

    Mohandas, Gopakumar; Pessah, Martin E., E-mail: gopakumar@nbi.ku.dk, E-mail: mpessah@nbi.ku.dk [Niels Bohr International Academy, Niels Bohr Institute, Blegdamsvej 17, DK-2100, Copenhagen Ø (Denmark)

    2017-03-20

    The effect of magnetic field diffusion on the stability of accretion disks is a problem that has attracted considerable interest of late. In particular, the Hall effect has the potential to bring about remarkable changes in the dynamical behavior of disks that are without parallel. In this paper, we conduct a systematic examination of the linear eigenmodes in a weakly magnetized differentially rotating gas with a special focus on Hall diffusion. We first develop a geometrical representation of the eigenmodes and provide a detailed quantitative description of the polarization properties of the oscillatory modes under the combined influence of the Coriolis and Hall effects. We also analyze the effects of magnetic diffusion on the structure of the unstable modes and derive analytical expressions for the kinetic and magnetic stresses and energy densities associated with the non-ideal magnetorotational instability (MRI). Our analysis explicitly demonstrates that, if the dissipative effects are relatively weak, the kinetic stresses and energies make up the dominant contribution to the total stress and energy density when the equilibrium angular momentum and magnetic field vectors are anti-parallel. This is in sharp contrast to what is observed in the case of the ideal or dissipative MRI. We conduct shearing box simulations and find very good agreement with the results derived from linear theory. Because the modes under consideration are also exact solutions of the nonlinear equations, the unconventional nature of the kinetic and magnetic stresses may have significant implications for the nonlinear evolution in some regions of protoplanetary disks.

  3. Numerical simulation of double front detonations in a non-ideal explosive with varying aluminum concentration

    Science.gov (United States)

    Kim, Wuhyun; Gwak, Min-Cheol; Yoh, Jack; Seoul National University Team

    2017-06-01

    The performance characteristics of aluminized HMX are considered by varying the aluminum (Al) concentration in a hybrid non-ideal detonation model. Two cardinal observations are reported: a decrease in detonation velocity with an increase in Al concentration and a double front detonation (DFD) feature when aerobic Al reaction occurs behind the front. While experimental studies have been reported on the effect of Al concentration on both gas-phase and solid-phase detonations, the numerical investigations were limited to only gas-phase detonation for the varying Al concentration. In the current study, a two-phase model is utilized for understanding the volumetric effects of Al concentration in the condensed phase detonations. A series of unconfined and confined rate sticks are considered for characterizing the performance of aluminized HMX with a maximum Al concentration of 50%. The simulated results are compared with the experimental data for 5%-25% concentrations, and the formation of DFD structure under varying Al concentration (0%-50%) in HMX is investigated.

  4. THE SMALL-SCALE DYNAMO AND NON-IDEAL MAGNETOHYDRODYNAMICS IN PRIMORDIAL STAR FORMATION

    Energy Technology Data Exchange (ETDEWEB)

    Schober, Jennifer; Federrath, Christoph; Glover, Simon; Klessen, Ralf S. [Zentrum fuer Astronomie der Universitaet Heidelberg, Institut fuer Theoretische Astrophysik, Albert-Ueberle-Str. 2, D-69120 Heidelberg (Germany); Schleicher, Dominik [Institut fuer Astrophysik, Georg-August-Universitaet Goettingen, Friedrich-Hund-Platz, D-37077 Goettingen (Germany); Banerjee, Robi, E-mail: schober@stud.uni-heidelberg.de, E-mail: christoph.federrath@monash.edu, E-mail: glover@uni-heidelberg.de, E-mail: klessen@uni-heidelberg.de, E-mail: dschleic@astro.physik.uni-goettingen.de, E-mail: banerjee@hs.uni-hamburg.de [Hamburger Sternwarte, Gojenbergsweg 112, D-21029 Hamburg (Germany)

    2012-08-01

    We study the amplification of magnetic fields during the formation of primordial halos. The turbulence generated by gravitational infall motions during the formation of the first stars and galaxies can amplify magnetic fields very efficiently and on short timescales up to dynamically significant values. Using the Kazantsev theory, which describes the so-called small-scale dynamo-a magnetohydrodynamical process converting kinetic energy from turbulence into magnetic energy-we can then calculate the growth rate of the small-scale magnetic field. Our calculations are based on a detailed chemical network and we include non-ideal magnetohydrodynamical effects such as ambipolar diffusion and Ohmic dissipation. We follow the evolution of the magnetic field up to larger scales until saturation occurs on the Jeans scale. Assuming a weak magnetic seed field generated by the Biermann battery process, both Burgers and Kolmogorov turbulence lead to saturation within a rather small density range. Such fields are likely to become relevant after the formation of a protostellar disk and, thus, could influence the formation of the first stars and galaxies in the universe.

  5. Numerical study of shock waves in non-ideal magnetogasdynamics (MHD

    Directory of Open Access Journals (Sweden)

    Addepalli Ramu

    2016-01-01

    Full Text Available One-dimensional unsteady adiabatic flow of strong converging shock waves in cylindrical or spherical symmetry in MHD, which is propagating into plasma, is analyzed. The plasma is assumed to be non-ideal gas whose equation of state is of Mie–Gruneisen type. Suitable transformations reduce the governing equations into ordinary differential equations of Poincare type. In the present work, McQueen and Royce equations of state (EOS have been considered with suitable material constants and the spherical and cylindrical cases are worked out in detail to investigate the behavior and the influence on the shock wave propagation by energy input and β(ρ/ρ0, the measure of shock strength. The similarity solution is valid for adiabatic flow as long as the counter pressure is neglected. The numerical technique applied in this paper provides a global solution to the implosion problem for the flow variables, the similarity exponent α for different Gruneisen parameters. It is shown that increasing β(ρ/ρ0 does not automatically decelerate the shock front but the velocity and pressure behind the shock front increases quickly in the presence of the magnetic field and decreases slowly and become constant. This becomes true whether the piston is accelerated, is moving at constant speed or is decelerated. These results are presented through the illustrative graphs and tables. The magnetic field effects on the flow variables through a medium and total energy under the influence of strong magnetic field are also presented.

  6. Design of High-Entropy Alloy: A Perspective from Nonideal Mixing

    Science.gov (United States)

    He, Q. F.; Ding, Z. Y.; Ye, Y. F.; Yang, Y.

    2017-11-01

    Since the advent in 2004, high-entropy alloys (HEAs) have been attracting a great deal of research interest worldwide. Being deemed as a major paradigmatic shift, the design of HEAs without base elements poses challenges to the existing thermodynamic models and theories that were long established for traditional alloys, one of which is related to the thermodynamic mechanisms for the formation of random solid solution in a concentrated multicomponent alloy. In this article, we discuss the design of HEAs from the perspective of correlated mixing (nonideal mixing of atoms with interatomic correlations). In a quantitative manner, we can show that the formation of a random solid solution in HEAs depends not only on the number of constituent elements but also on the alloy's melting/processing temperature and on various interatomic correlations. Through the correlated mixing rule, we further demonstrate a strategy to screen out equiatomic alloys with the thermodynamic characteristics close to those of random solid solutions from an expanded library of 20 candidate elements.

  7. Deciding which chemical mixtures risk assessment methods work best for what mixtures

    International Nuclear Information System (INIS)

    Teuschler, Linda K.

    2007-01-01

    The most commonly used chemical mixtures risk assessment methods involve simple notions of additivity and toxicological similarity. Newer methods are emerging in response to the complexities of chemical mixture exposures and effects. Factors based on both science and policy drive decisions regarding whether to conduct a chemical mixtures risk assessment and, if so, which methods to employ. Scientific considerations are based on positive evidence of joint toxic action, elevated human exposure conditions or the potential for significant impacts on human health. Policy issues include legislative drivers that may mandate action even though adequate toxicity data on a specific mixture may not be available and risk assessment goals that impact the choice of risk assessment method to obtain the amount of health protection desired. This paper discusses three important concepts used to choose among available approaches for conducting a chemical mixtures risk assessment: (1) additive joint toxic action of mixture components; (2) toxicological interactions of mixture components; and (3) chemical composition of complex mixtures. It is proposed that scientific support for basic assumptions used in chemical mixtures risk assessment should be developed by expert panels, risk assessment methods experts, and laboratory toxicologists. This is imperative to further develop and refine quantitative methods and provide guidance on their appropriate applications. Risk assessors need scientific support for chemical mixtures risk assessment methods in the form of toxicological data on joint toxic action for high priority mixtures, statistical methods for analyzing dose-response for mixtures, and toxicological and statistical criteria for determining sufficient similarity of complex mixtures

  8. Optimal mixture experiments

    CERN Document Server

    Sinha, B K; Pal, Manisha; Das, P

    2014-01-01

    The book dwells mainly on the optimality aspects of mixture designs. As mixture models are a special case of regression models, a general discussion on regression designs has been presented, which includes topics like continuous designs, de la Garza phenomenon, Loewner order domination, Equivalence theorems for different optimality criteria and standard optimality results for single variable polynomial regression and multivariate linear and quadratic regression models. This is followed by a review of the available literature on estimation of parameters in mixture models. Based on recent research findings, the volume also introduces optimal mixture designs for estimation of optimum mixing proportions in different mixture models, which include Scheffé’s quadratic model, Darroch-Waller model, log- contrast model, mixture-amount models, random coefficient models and multi-response model.  Robust mixture designs and mixture designs in blocks have been also reviewed. Moreover, some applications of mixture desig...

  9. Adaptive Numerical Dissipative Control in High Order Schemes for Multi-D Non-Ideal MHD

    Science.gov (United States)

    Yee, H. C.; Sjoegreen, B.

    2004-01-01

    The goal is to extend our adaptive numerical dissipation control in high order filter schemes and our new divergence-free methods for ideal MHD to non-ideal MHD that include viscosity and resistivity. The key idea consists of automatic detection of different flow features as distinct sensors to signal the appropriate type and amount of numerical dissipation/filter where needed and leave the rest of the region free of numerical dissipation contamination. These scheme-independent detectors are capable of distinguishing shocks/shears, flame sheets, turbulent fluctuations and spurious high-frequency oscillations. The detection algorithm is based on an artificial compression method (ACM) (for shocks/shears), and redundant multi-resolution wavelets (WAV) (for the above types of flow feature). These filter approaches also provide a natural and efficient way for the minimization of Div(B) numerical error. The filter scheme consists of spatially sixth order or higher non-dissipative spatial difference operators as the base scheme for the inviscid flux derivatives. If necessary, a small amount of high order linear dissipation is used to remove spurious high frequency oscillations. For example, an eighth-order centered linear dissipation (AD8) might be included in conjunction with a spatially sixth-order base scheme. The inviscid difference operator is applied twice for the viscous flux derivatives. After the completion of a full time step of the base scheme step, the solution is adaptively filtered by the product of a 'flow detector' and the 'nonlinear dissipative portion' of a high-resolution shock-capturing scheme. In addition, the scheme independent wavelet flow detector can be used in conjunction with spatially compact, spectral or spectral element type of base schemes. The ACM and wavelet filter schemes using the dissipative portion of a second-order shock-capturing scheme with sixth-order spatial central base scheme for both the inviscid and viscous MHD flux

  10. Magnetogasdynamic spherical shock wave in a non-ideal gas under gravitational field with conductive and radiative heat fluxes

    Science.gov (United States)

    Nath, G.; Vishwakarma, J. P.

    2016-11-01

    Similarity solutions are obtained for the flow behind a spherical shock wave in a non-ideal gas under gravitational field with conductive and radiative heat fluxes, in the presence of a spatially decreasing azimuthal magnetic field. The shock wave is driven by a piston moving with time according to power law. The radiation is considered to be of the diffusion type for an optically thick grey gas model and the heat conduction is expressed in terms of Fourier's law for heat conduction. Similarity solutions exist only when the surrounding medium is of constant density. The gas is assumed to have infinite electrical conductivity and to obey a simplified van der Waals equation of state. It is shown that an increase of the gravitational parameter or the Alfven-Mach number or the parameter of the non-idealness of the gas decreases the compressibility of the gas in the flow-field behind the shock, and hence there is a decrease in the shock strength. The pressure and density vanish at the inner surface (piston) and hence a vacuum is formed at the center of symmetry. The shock waves in conducting non-ideal gas under gravitational field with conductive and radiative heat fluxes can be important for description of shocks in supernova explosions, in the study of a flare produced shock in the solar wind, central part of star burst galaxies, nuclear explosion etc. The solutions obtained can be used to interpret measurements carried out by space craft in the solar wind and in neighborhood of the Earth's magnetosphere.

  11. The effect of multicomponent diffusion on NAPL dissolution from spherical ternary mixtures

    Science.gov (United States)

    Brahma, Priti P.; Harmon, Thomas C.

    2003-12-01

    This paper investigates the dissolution characteristics of ternary nonaqueous phase liquid (NAPL) mixtures with the goal of comparing the relative contributions of multicomponent (intra-NAPL) diffusion, film transfer and thermodynamic nonideality. These contributions are compared at the pore scale and intermediate scale (several centimeters downstream from the source). Trichloroethene (TCE), tetrachloroethene (PCE) and 1,1,1-trichloroethane (TCA) were selected to model a reasonably ideal mixture; TCE, PCE and octanol were selected as a relevant nonideal mixture. A multicomponent diffusion-based dissolution model incorporating hydrodynamic theory was formulated to estimate intra-NAPL concentration gradients and associated aqueous interfacial concentrations for ideally shaped (spherical) NAPL blobs. Pore scale dissolution times for this model were compared to those generated using the conventional well-mixed NAPL dissolution model, applying the same film transfer boundary condition in both cases. Activity coefficients (spatially and temporally variable for the diffusion model, temporally variable for the well-mixed model) were estimated using UNIFAC. NAPL interfacial concentration histories generated using the pore scale models were used as input in a three-dimensional groundwater transport model (MT3DMS) to compare downstream concentration distributions. For the relatively large NAPL bodies simulated ( r=0.6 cm), intra-NAPL diffusion effects were found to be significant at the pore scale and were strongly impacted by the mixture's thermodynamic ideality. At the intermediate scale, and for the conditions tested, modest differences in the simulations suggested that intra-NAPL diffusion effects would be negligible compared to those associated with mixture composition uncertainty, dissolution rate processes related to NAPL-induced permeability effects and hydrodynamic issues associated with flow field heterogeneity.

  12. Design of the Modelica Library VehProLib with Non-ideal Gas Models in Engines

    OpenAIRE

    Andersson, Conny

    2015-01-01

    This thesis covers the reconstruction and the redesign of the modeling library VehProLib,which is constructed in the modeling language Modelica with help of the modeling toolWolfram SystemModeler. The design choices are discussed and implemented. This thesisalso includes the implementation of a turbocharger package and an initial study of the justificationof the ideal gas law in vehicle modeling. The study is made with help of Van derWaals equation of states as a reference of non-ideal gas mo...

  13. Liquids and liquid mixtures

    CERN Document Server

    Rowlinson, J S; Baldwin, J E; Buckingham, A D; Danishefsky, S

    2013-01-01

    Liquids and Liquid Mixtures, Third Edition explores the equilibrium properties of liquids and liquid mixtures and relates them to the properties of the constituent molecules using the methods of statistical thermodynamics. Topics covered include the critical state, fluid mixtures at high pressures, and the statistical thermodynamics of fluids and mixtures. This book consists of eight chapters and begins with an overview of the liquid state and the thermodynamic properties of liquids and liquid mixtures, including vapor pressure and heat capacities. The discussion then turns to the thermodynami

  14. Nonlinear dynamics and control strategies: On a energy harvester vibrating system with a linear form to non-ideal motor torquet

    Directory of Open Access Journals (Sweden)

    de Pontes B. R.

    2012-07-01

    Full Text Available In this paper, we deal with the research of a vibrating model of an energy harvester device, including the nonlinearities in the model of the piezoelectric coupling and the non-ideal excitation. We show, using numerical simulations, in the analysis of the dynamic responses, that the harvested power is influenced by non-linear vibrations of the structure. Chaotic behavior was also observed, causing of the loss of energy throughout the simulation time. Using a perturbation technique, we find an approximate analytical solution for the non-ideal system. Then, we apply both two control techniques, to keep the considered system, into a stable condition. Both the State Dependent Ricatti Equation (SDRE control as the feedback control by changing the energy of the oscillator, were efficient in controlling of the considered non-ideal system.

  15. Phase behaviour in water/hydrocarbon mixtures involved in gas production systems; etude des equilibres des systemes: eau-hydrocarbures-gaz acides dans le cadre de la production de gaz

    Energy Technology Data Exchange (ETDEWEB)

    Chapoy, A.

    2004-11-15

    Inside wells, natural gases frequently coexist with water. The gases are in equilibrium with the sub-adjacent aquifer. Many problems are associated with the presence of water during the production, transport and processing of natural gases. Accurate knowledge of the thermodynamic properties of the water/hydrocarbon and water-inhibitor/hydrocarbon equilibria near the hydrate forming conditions, at sub-sea pipeline conditions and during the transport is crucial for the petroleum industry. An apparatus based on a static/analytic method combined with a dilutor apparatus to calibrate on the gas chromatograph (GC) detectors with water was used to measure the water content of binary systems (i.e.: water - methane, ethane - water, nitrogen - water...) as well of a synthetic hydrocarbon gas mixture (i.e.: 94% methane, 4% ethane and 2% n-butane) with and without inhibitor. This same apparatus was also used generate data of methane, ethane, propane, n-butane and nitrogen solubility in water and also the solubilities of a synthetic mixture in water. In-house software has been developed in order to fit and model the experimental data. (author)

  16. Experimental determination of critical data of multi-component mixtures containing potential gasoline additives 2-butanol by a flow-type apparatus

    International Nuclear Information System (INIS)

    He, Maogang; Xin, Nan; Wang, Chengjie; Liu, Yang; Zhang, Ying; Liu, Xiangyang

    2016-01-01

    Graphical abstract: Experimental critical pressures of 2-butanol + hexane + heptane system. - Highlights: • Critical properties of six binary systems and two ternary systems were measured. • Six binary systems containing 2-butanol show non-ideal behavior in their T c –x 1 curves. • Non-ideal behavior of mixtures with 2-butanol relies on azeotropy. • Experimental data for binary systems were fitted well with Redlich–Kister equation. • Critical surfaces of ternary systems were plotted using the Cibulka’s expressions. - Abstract: In this work, we used a flow method for measurement of critical properties of six binary mixtures (2-butanol + cyclohexane, 2-butanol + hexane, 2-butanol + heptane, 2-butanol + octane, 2-butanol + nonane and 2-butanol + decane) and two ternary mixtures (2-butanol + hexane + heptane and 2-butanol + octane + decane). The critical properties were determined by observing the disappearance and reappearance of the gas–liquid phase meniscus in a quartz glass tube. The standard uncertainties of temperatures and pressures for both binary and ternary mixtures were estimated to be less than 0.2 K and 5.2 kPa, respectively. These critical data provide the boundaries of the two-phase regions of the related mixture systems. Six binary systems show non-ideal behaviors in the loci of critical temperatures. We used the Redlich–Kister equations to correlate the critical temperatures and pressures of these systems and listed the binary interaction parameters. The maximum average absolute deviation (AAD) of each binary system between experimental data and calculated results from Redlich–Kister equations is 0.038% for critical temperatures, and 0.244% for critical pressures. Moreover, the two ternary systems were newly reported and correlated by Cibulka’s and Singh’s expressions. The maximum AAD of critical temperatures and critical pressures are 0.103% and 0.433%, respectively.

  17. Study of surface tension and surface properties of binary alcohol/n-alkyl acetate mixtures.

    Science.gov (United States)

    Rafati, Amir Abbas; Ghasemian, Ensieh

    2008-12-15

    The Butler equation is employed to describe quantitatively the nature, properties, and compositions of surface layers in binary liquid mixtures. Bulk mole fraction, surface molar area, and surface tension of pure components are necessary inputs for this equation. In addition, the UNIFAC group contribution method is applied to account for the nonideality of the bulk liquid as well as that of the surface layer. The average relative error obtained from the comparison of experimental and calculated surface tension values for 12 binary systems is less than 1%. Therefore, the model has good accuracy in comparison with other predictive equations. In addition to finding more information about the surface structure of binary mixtures, surface mole fraction was calculated using relative Gibbs adsorption values and an extended Langmuir model (EL). The obtained results show a good consistency between two models employed, i.e., the Gibbs adsorption model and EL model, based on the UNIFAC method.

  18. Lifshitz phase: the microscopic structure of aqueous and ethanol mixtures of 1,n-diols.

    Science.gov (United States)

    Požar, Martina; Perera, Aurélien

    2017-06-14

    We study binary mixtures of ethylene glycol and 1,3-propandiol with water or ethanol using computer simulations. Despite strong hydrogen bonding tendencies between all these molecules, we find that these mixtures are surprisingly homogeneous, in contrast to the strong micro-heterogeneity found in aqueous ethanol mixtures. The aqueous diol mixtures are found to be close to ideal mixtures, with near-ideal Kirkwood-Buff integrals. Ethanol-diol mixtures show weak non-ideality. The origin of this unexpected randomness is due to the fact that the two hydrogen bonding hydroxyl groups of the 1,n-diol are bound by the neutral alkyl bond, which prevents the micro-segregation of the different types of hydroxyl groups. These findings suggest that random disorder can arise in the presence of strong interactions - in contrast to the usual picture of random disorder due to weak interactions between the components. They point to the important role of molecular topology in tuning concentration fluctuations in complex liquids. We propose and justify herein the name of Lifshitz phases to designate such types of disordered systems.

  19. Optimal (Solvent) Mixture Design through a Decomposition Based CAMD methodology

    OpenAIRE

    Achenie, L.; Karunanithi, Arunprakash T.; Gani, Rafiqul

    2004-01-01

    Computer Aided Molecular/Mixture design (CAMD) is one of the most promising techniques for solvent design and selection. A decomposition based CAMD methodology has been formulated where the mixture design problem is solved as a series of molecular and mixture design sub-problems. This approach is able to overcome most of the difficulties associated with the solution of mixture design problems. The new methodology has been illustrated with the help of a case study involving the design of solve...

  20. Separation of organic azeotropic mixtures by pervaporation

    Energy Technology Data Exchange (ETDEWEB)

    Baker, R.W.

    1991-12-01

    Distillation is a commonly used separation technique in the petroleum refining and chemical processing industries. However, there are a number of potential separations involving azetropic and close-boiling organic mixtures that cannot be separated efficiently by distillation. Pervaporation is a membrane-based process that uses selective permeation through membranes to separate liquid mixtures. Because the separation process is not affected by the relative volatility of the mixture components being separated, pervaporation can be used to separate azetropes and close-boiling mixtures. Our results showed that pervaporation membranes can be used to separate azeotropic mixtures efficiently, a result that is not achievable with simple distillation. The membranes were 5--10 times more permeable to one of the components of the mixture, concentrating it in the permeate stream. For example, the membrane was 10 times more permeable to ethanol than methyl ethyl ketone, producing 60% ethanol permeate from an azeotropic mixture of ethanol and methyl ethyl ketone containing 18% ethanol. For the ethyl acetate/water mixture, the membranes showed a very high selectivity to water (> 300) and the permeate was 50--100 times enriched in water relative to the feed. The membranes had permeate fluxes on the order of 0.1--1 kg/m{sup 2}{center dot}h in the operating range of 55--70{degrees}C. Higher fluxes were obtained by increasing the operating temperature.

  1. Experiments with Mixtures Designs, Models, and the Analysis of Mixture Data

    CERN Document Server

    Cornell, John A

    2011-01-01

    The most comprehensive, single-volume guide to conducting experiments with mixtures"If one is involved, or heavily interested, in experiments on mixtures of ingredients, one must obtain this book. It is, as was the first edition, the definitive work."-Short Book Reviews (Publication of the International Statistical Institute)"The text contains many examples with worked solutions and with its extensive coverage of the subject matter will prove invaluable to those in the industrial and educational sectors whose work involves the design and analysis of mixture experiments."-Journal of the Royal S

  2. Impact of co-channel interference on the performance of adaptive non-ideal generalized transmit diversity

    KAUST Repository

    Radaydeh, Redha Mahmoud Mesleh

    2010-09-01

    The impact of co-channel interference and nonideal estimation of the desired user channel state information (CSI) on the performance of an adaptive threshold-based generalized transmit diversity for low-complexity multiple-input single-output configuration is investigated. The adaptation to channel conditions is assumed to be based on the desired user CSI, and the number of active transmit antennas is adjusted accordingly to guarantee predetermined target performance. To facilitate comparisons between different adaptation schemes, new analytical results for the statistics of combined signal-to-interference-plus-noise ratio (SINR) are derived, which can be applied for different fading conditions of interfering signals. Selected numerical results are presented to validate the analytical development and to compare the outage performance of the considered adaptation schemes. © 2010 IEEE.

  3. Effect of small anisotropy and absorption on metamaterial applications: "non-ideal" features of propagation and tunneling of electromagnetic waves

    Science.gov (United States)

    Starodubtsev, Evgenii

    2018-02-01

    For cases of isotropic, uniaxial, and biaxial electromagnetic metamaterials (MM), a comparative analysis of the effect of small deviations of local material parameters from "ideal" values on the realization of MM applications ("zero" media, the Veselago-Pendry superlens) has been carried out. On the basis of the detailed investigation of the solutions of dispersion equations, it is established that even a very small dielectric and (or) magnetic anisotropy of a general form is the universal "non-ideal" factor determining (to a much greater extent than small losses) the operability of those MM applications where the wave misphasing in the effective medium is undesirable. The characteristics of wave attenuation in the absorbing isotropic and weakly anisotropic MM are mainly comparable for the applications. Limitations of the traditional approaches using the second-order curves (or surfaces) for analytic modeling of the absorbing MM dispersion equations are shown.

  4. Non-ideality in Born-free energy of solvation in alcohol–water and ...

    Indian Academy of Sciences (India)

    WINTEC

    lowing expression of Born-energy (EBorn) for an ion dissolved in binary mixture of dipolar solvents with unequal size and different dipole moments. 2. Born. 2. 1. 3. E k k k k. z e. E. H α α ρ μ. = −. ∑. 2. 2. 1. 3. E k k k k. z e. H α α ρ μ. = −. ∑ . (9). Now we need to calculate 1 (. 1 ). E. E k k. H. H α α. = Baxter factorization80,90 ...

  5. Perception of trigeminal mixtures.

    Science.gov (United States)

    Filiou, Renée-Pier; Lepore, Franco; Bryant, Bruce; Lundström, Johan N; Frasnelli, Johannes

    2015-01-01

    The trigeminal system is a chemical sense allowing for the perception of chemosensory information in our environment. However, contrary to smell and taste, we lack a thorough understanding of the trigeminal processing of mixtures. We, therefore, investigated trigeminal perception using mixtures of 3 relatively receptor-specific agonists together with one control odor in different proportions to determine basic perceptual dimensions of trigeminal perception. We found that 4 main dimensions were linked to trigeminal perception: sensations of intensity, warmth, coldness, and pain. We subsequently investigated perception of binary mixtures of trigeminal stimuli by means of these 4 perceptual dimensions using different concentrations of a cooling stimulus (eucalyptol) mixed with a stimulus that evokes warmth perception (cinnamaldehyde). To determine if sensory interactions are mainly of central or peripheral origin, we presented stimuli in a physical "mixture" or as a "combination" presented separately to individual nostrils. Results showed that mixtures generally yielded higher ratings than combinations on the trigeminal dimensions "intensity," "warm," and "painful," whereas combinations yielded higher ratings than mixtures on the trigeminal dimension "cold." These results suggest dimension-specific interactions in the perception of trigeminal mixtures, which may be explained by particular interactions that may take place on peripheral or central levels. © The Author 2014. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  6. Ionic liquid mixtures-variations in physical properties and their origins in molecular structure.

    Science.gov (United States)

    Annat, Gary; Forsyth, Maria; MacFarlane, Douglas R

    2012-07-19

    In order to explore the various possible property trends in ionic liquid mixtures, five different ionic liquids were mixed with N-methyl-N-propylpyrrolidinium bis(trifluoromethylsulfonyl)amide ([C3mpyr][NTf2]), and the viscosities, excess molar volumes, ionic conductivities, and phase diagrams of the mixtures were determined over a range of temperatures. In a number of the mixtures the crystallization of both components was completely suppressed and no melting point was observable. Such mixtures of similar ionic liquids thus have potential for use in low-temperature applications by extending the liquid range to T(g). The molar conductivities and viscosities are described as approximating predictable or "simple" mixing behaviors, while excess molar volumes were found to show a variety of mixing and nonideal mixing effects. Mixture equations for viscosity and conductivity are discussed and analyzed. An immiscibility window was observed in the trihexyl(tetradecyl)phosphonium bis(trifluoromethylsulfonyl)amide ([P(6,6,6,14)][NTf2]) in the [C3mpyr][NTf2] system in the [C3mpyr][NTf2]-rich region. Unusual physical properties are exhibited by miscible compositions near the demixing line. These compositions are described as [P(6,6,6,14)][NTf2]-like, even up to 0.5 mol fraction of [C3mpyr][NTf2].

  7. Identifying Mixtures of Mixtures Using Bayesian Estimation

    Science.gov (United States)

    Malsiner-Walli, Gertraud; Frühwirth-Schnatter, Sylvia; Grün, Bettina

    2017-01-01

    ABSTRACT The use of a finite mixture of normal distributions in model-based clustering allows us to capture non-Gaussian data clusters. However, identifying the clusters from the normal components is challenging and in general either achieved by imposing constraints on the model or by using post-processing procedures. Within the Bayesian framework, we propose a different approach based on sparse finite mixtures to achieve identifiability. We specify a hierarchical prior, where the hyperparameters are carefully selected such that they are reflective of the cluster structure aimed at. In addition, this prior allows us to estimate the model using standard MCMC sampling methods. In combination with a post-processing approach which resolves the label switching issue and results in an identified model, our approach allows us to simultaneously (1) determine the number of clusters, (2) flexibly approximate the cluster distributions in a semiparametric way using finite mixtures of normals and (3) identify cluster-specific parameters and classify observations. The proposed approach is illustrated in two simulation studies and on benchmark datasets. Supplementary materials for this article are available online. PMID:28626349

  8. SEPARATION OF FLUID MIXTURES

    Science.gov (United States)

    Lipscomb, R.; Craig, A.; Labrow, S.; Dunn, J.F.

    1958-10-28

    An apparatus is presented for separating gaseous mixtures by selectively freezing a constituent of the mixture and subsequently separating the frozen gas. The gas mixture is passed through a cylinder fltted with a cooling jacket, causing one gas to freeze on the walls of the cylinder. A set of scraper blades are provided in the interior of the cyllnder, and as the blades oscillate, the frozen gas is scraped to the bottom of the cylinder. Means are provided for the frozen material to pass into a heating chamber where it is vaporized and the product gas collected.

  9. Iterative Mixture Component Pruning Algorithm for Gaussian Mixture PHD Filter

    Directory of Open Access Journals (Sweden)

    Xiaoxi Yan

    2014-01-01

    Full Text Available As far as the increasing number of mixture components in the Gaussian mixture PHD filter is concerned, an iterative mixture component pruning algorithm is proposed. The pruning algorithm is based on maximizing the posterior probability density of the mixture weights. The entropy distribution of the mixture weights is adopted as the prior distribution of mixture component parameters. The iterative update formulations of the mixture weights are derived by Lagrange multiplier and Lambert W function. Mixture components, whose weights become negative during iterative procedure, are pruned by setting corresponding mixture weights to zeros. In addition, multiple mixture components with similar parameters describing the same PHD peak can be merged into one mixture component in the algorithm. Simulation results show that the proposed iterative mixture component pruning algorithm is superior to the typical pruning algorithm based on thresholds.

  10. Spectroscopic and DFT study of solvent effects on the electronic absorption spectra of sulfamethoxazole in neat and binary solvent mixtures.

    Science.gov (United States)

    Almandoz, M C; Sancho, M I; Blanco, S E

    2014-01-24

    The solvatochromic behavior of sulfamethoxazole (SMX) was investigated using UV-vis spectroscopy and DFT methods in neat and binary solvent mixtures. The spectral shifts of this solute were correlated with the Kamlet and Taft parameters (α, β and π(*)). Multiple lineal regression analysis indicates that both specific hydrogen-bond interaction and non specific dipolar interaction play an important role in the position of the absorption maxima in neat solvents. The simulated absorption spectra using TD-DFT methods were in good agreement with the experimental ones. Binary mixtures consist of cyclohexane (Cy)-ethanol (EtOH), acetonitrile (ACN)-dimethylsulfoxide (DMSO), ACN-dimethylformamide (DMF), and aqueous mixtures containing as co-solvents DMSO, ACN, EtOH and MeOH. Index of preferential solvation was calculated as a function of solvent composition and non-ideal characteristics are observed in all binary mixtures. In ACN-DMSO and ACN-DMF mixtures, the results show that the solvents with higher polarity and hydrogen bond donor ability interact preferentially with the solute. In binary mixtures containing water, the SMX molecules are solvated by the organic co-solvent (DMSO or EtOH) over the whole composition range. Synergistic effect is observed in the case of ACN-H2O and MeOH-H2O, indicating that at certain concentrations solvents interact to form association complexes, which should be more polar than the individual solvents of the mixture. Copyright © 2013 Elsevier Ltd. All rights reserved.

  11. Optimal (Solvent) Mixture Design through a Decomposition Based CAMD methodology

    DEFF Research Database (Denmark)

    Achenie, L.; Karunanithi, Arunprakash T.; Gani, Rafiqul

    2004-01-01

    Computer Aided Molecular/Mixture design (CAMD) is one of the most promising techniques for solvent design and selection. A decomposition based CAMD methodology has been formulated where the mixture design problem is solved as a series of molecular and mixture design sub-problems. This approach is...... is able to overcome most of the difficulties associated with the solution of mixture design problems. The new methodology has been illustrated with the help of a case study involving the design of solvent-anti solvent binary mixtures for crystallization of Ibuprofen....

  12. Mixtures Estimation and Applications

    CERN Document Server

    Mengersen, Kerrie; Titterington, Mike

    2011-01-01

    This book uses the EM (expectation maximization) algorithm to simultaneously estimate the missing data and unknown parameter(s) associated with a data set. The parameters describe the component distributions of the mixture; the distributions may be continuous or discrete. The editors provide a complete account of the applications, mathematical structure and statistical analysis of finite mixture distributions along with MCMC computational methods, together with a range of detailed discussions covering the applications of the methods and features chapters from the leading experts on the subject

  13. Exact Fit of Simple Finite Mixture Models

    Directory of Open Access Journals (Sweden)

    Dirk Tasche

    2014-11-01

    Full Text Available How to forecast next year’s portfolio-wide credit default rate based on last year’s default observations and the current score distribution? A classical approach to this problem consists of fitting a mixture of the conditional score distributions observed last year to the current score distribution. This is a special (simple case of a finite mixture model where the mixture components are fixed and only the weights of the components are estimated. The optimum weights provide a forecast of next year’s portfolio-wide default rate. We point out that the maximum-likelihood (ML approach to fitting the mixture distribution not only gives an optimum but even an exact fit if we allow the mixture components to vary but keep their density ratio fixed. From this observation we can conclude that the standard default rate forecast based on last year’s conditional default rates will always be located between last year’s portfolio-wide default rate and the ML forecast for next year. As an application example, cost quantification is then discussed. We also discuss how the mixture model based estimation methods can be used to forecast total loss. This involves the reinterpretation of an individual classification problem as a collective quantification problem.

  14. Similarity solution for the flow behind a shock wave in a non-ideal gas with heat conduction and radiation heat-flux in magnetogasdynamics

    Science.gov (United States)

    Nath, G.; Vishwakarma, J. P.

    2014-05-01

    The propagation of a spherical (or cylindrical) shock wave in a non-ideal gas with heat conduction and radiation heat-flux, in the presence of a spacially decreasing azimuthal magnetic field, driven out by a moving piston is investigated. The heat conduction is expressed in terms of Fourier's law and the radiation is considered to be of the diffusion type for an optically thick grey gas model. The thermal conductivity K and the absorption coefficient αR are assumed to vary with temperature and density. The gas is assumed to have infinite electrical conductivity and to obey a simplified van der Waals equation of state. The shock wave moves with variable velocity and the total energy of the wave is non-constant. Similarity solutions are obtained for the flow-field behind the shock and the effects of variation of the heat transfer parameters, the parameter of the non-idealness of the gas, both, decreases the compressibility of the gas and hence there is a decrease in the shock strength. Further, it is investigated that with an increase in the parameters of radiative and conductive heat transfer the tendency of formation of maxima in the distributions of heat flux, density and isothermal speed of sound decreases. The pressure and density vanish at the inner surface (piston) and hence a vacuum is form at the center of symmetry. The shock waves in conducting non-ideal gas with conductive and radiative heat fluxes can be important for description of shocks in supernova explosions, in the study of central part of star burst galaxies, nuclear explosion, chemical detonation, rupture of a pressurized vessels, in the analysis of data from exploding wire experiments, and cylindrically symmetric hypersonic flow problems associated with meteors or reentry vehicles, etc. The findings of the present works provided a clear picture of whether and how the non-idealness parameter, conductive and radiative heat transfer parameters and the magnetic field affect the flow behind the shock

  15. I-optimal mixture designs

    OpenAIRE

    GOOS, Peter; JONES, Bradley; SYAFITRI, Utami

    2013-01-01

    In mixture experiments, the factors under study are proportions of the ingredients of a mixture. The special nature of the factors in a mixture experiment necessitates specific types of regression models, and specific types of experimental designs. Although mixture experiments usually are intended to predict the response(s) for all possible formulations of the mixture and to identify optimal proportions for each of the ingredients, little research has been done concerning their I-optimal desi...

  16. Similarity solutions for unsteady flow behind an exponential shock in a self-gravitating non-ideal gas with azimuthal magnetic field

    Science.gov (United States)

    Nath, G.; Pathak, R. P.; Dutta, Mrityunjoy

    2018-01-01

    Similarity solutions for the flow of a non-ideal gas behind a strong exponential shock driven out by a piston (cylindrical or spherical) moving with time according to an exponential law is obtained. Solutions are obtained, in both the cases, when the flow between the shock and the piston is isothermal or adiabatic. The shock wave is driven by a piston moving with time according to an exponential law. Similarity solutions exist only when the surrounding medium is of constant density. The effects of variation of ambient magnetic field, non-idealness of the gas, adiabatic exponent and gravitational parameter are worked out in detail. It is shown that the increase in the non-idealness of the gas or the adiabatic exponent of the gas or presence of magnetic field have decaying effect on the shock wave. Consideration of the isothermal flow and the self-gravitational field increase the shock strength. Also, the consideration of isothermal flow or the presence of magnetic field removes the singularity in the density distribution, which arises in the case of adiabatic flow. The result of our study may be used to interpret measurements carried out by space craft in the solar wind and in neighborhood of the Earth's magnetosphere.

  17. Gas-particle partitioning of atmospheric aerosols: interplay of physical state, non-ideal mixing and morphology.

    Science.gov (United States)

    Shiraiwa, Manabu; Zuend, Andreas; Bertram, Allan K; Seinfeld, John H

    2013-07-21

    Atmospheric aerosols, comprising organic compounds and inorganic salts, play a key role in air quality and climate. Mounting evidence exists that these particles frequently exhibit phase separation into predominantly organic and aqueous electrolyte-rich phases. As well, the presence of amorphous semi-solid or glassy particle phases has been established. Using the canonical system of ammonium sulfate mixed with organics from the ozone oxidation of α-pinene, we illustrate theoretically the interplay of physical state, non-ideality, and particle morphology affecting aerosol mass concentration and the characteristic timescale of gas-particle mass transfer. Phase separation can significantly affect overall particle mass and chemical composition. Semi-solid or glassy phases can kinetically inhibit the partitioning of semivolatile components and hygroscopic growth, in contrast to the traditional assumption that organic compounds exist in quasi-instantaneous gas-particle equilibrium. These effects have significant implications for the interpretation of laboratory data and the development of improved atmospheric air quality and climate models.

  18. Ideal, nonideal, and no-marker variables: The confirmatory factor analysis (CFA) marker technique works when it matters.

    Science.gov (United States)

    Williams, Larry J; O'Boyle, Ernest H

    2015-09-01

    A persistent concern in the management and applied psychology literature is the effect of common method variance on observed relations among variables. Recent work (i.e., Richardson, Simmering, & Sturman, 2009) evaluated 3 analytical approaches to controlling for common method variance, including the confirmatory factor analysis (CFA) marker technique. Their findings indicated significant problems with this technique, especially with nonideal marker variables (those with theoretical relations with substantive variables). Based on their simulation results, Richardson et al. concluded that not correcting for method variance provides more accurate estimates than using the CFA marker technique. We reexamined the effects of using marker variables in a simulation study and found the degree of error in estimates of a substantive factor correlation was relatively small in most cases, and much smaller than error associated with making no correction. Further, in instances in which the error was large, the correlations between the marker and substantive scales were higher than that found in organizational research with marker variables. We conclude that in most practical settings, the CFA marker technique yields parameter estimates close to their true values, and the criticisms made by Richardson et al. are overstated. (c) 2015 APA, all rights reserved).

  19. Analytical and Experimental Performance Evaluation of BLE Neighbor Discovery Process Including Non-Idealities of Real Chipsets.

    Science.gov (United States)

    Perez-Diaz de Cerio, David; Hernández, Ángela; Valenzuela, Jose Luis; Valdovinos, Antonio

    2017-03-03

    The purpose of this paper is to evaluate from a real perspective the performance of Bluetooth Low Energy (BLE) as a technology that enables fast and reliable discovery of a large number of users/devices in a short period of time. The BLE standard specifies a wide range of configurable parameter values that determine the discovery process and need to be set according to the particular application requirements. Many previous works have been addressed to investigate the discovery process through analytical and simulation models, according to the ideal specification of the standard. However, measurements show that additional scanning gaps appear in the scanning process, which reduce the discovery capabilities. These gaps have been identified in all of the analyzed devices and respond to both regular patterns and variable events associated with the decoding process. We have demonstrated that these non-idealities, which are not taken into account in other studies, have a severe impact on the discovery process performance. Extensive performance evaluation for a varying number of devices and feasible parameter combinations has been done by comparing simulations and experimental measurements. This work also includes a simple mathematical model that closely matches both the standard implementation and the different chipset peculiarities for any possible parameter value specified in the standard and for any number of simultaneous advertising devices under scanner coverage.

  20. Non-ideal effect in 4H-SiC bipolar junction transistor with double Gaussian-doped base

    Science.gov (United States)

    Yuan, Lei; Zhang, Yu-Ming; Song, Qing-Wen; Tang, Xiao-Yan; Zhang, Yi-Men

    2015-06-01

    The non-ideal effect of 4H-SiC bipolar junction transistor (BJT) with a double Gaussian-doped base is characterized and simulated in this paper. By adding a specific interface model between SiC and SiO2, the simulation results are in good agreement with the experiment data. An obvious early effect is found from the output characteristic. As the temperature rises, the early voltage increases, while the current gain gradually decreases, which is totally different from the scenario of silicon BJT. With the same effective Gummel number in the base region, the double Gaussian-doped base structure can realize higher current gain than the single base BJT due to the built-in electric field, whereas the early effect will be more salient. Besides, the emitter current crowding effect is also analyzed. Due to the low sheet resistance in the first highly-doped base epilayer, the 4H-BJT with a double base has more uniform emitter current density across the base-emitter junction, leading to better thermal stability. Project supported by the National Natural Science Foundation of China (Grant Nos. 60876061 and 61234006), the Natural Science Foundation of Shaanxi Province, China (Grant No. 2013JQ8012), and the Doctoral Fund of the Ministry of Education of China (Grant Nos. 20130203120017 and 20110203110010).

  1. The chemical equilibrium under non-ideal conditions: industrial applications; El equilibrio quimico bajo condiciones no ideales: aplicaciones industriales

    Energy Technology Data Exchange (ETDEWEB)

    Silva Martinez, Susana; Alvarez Gallegos, Alberto; Quere, Alain [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1993-05-01

    In this paper is described the application of a computer program to the chemical equilibrium in non-ideal conditions (aqueous solutions of multicomponent electrolytes in the ionic forces interval: 0 < 1 < 6 mol/Kg H{sub 2}O and temperatures close to 25 celsius degrees), and its importance at industrial scale. The calculation of the thermodynamic properties of the solution (activity coefficients, osmotic coefficient, and water activity) is based in one of the most modern theories of the electrolytes; the theoretical results, compared with the experimental ones have an error of 10% or better. [Espanol] En este trabajo se describe la aplicacion de un programa de computo al equilibrio quimico en condiciones no ideales (soluciones acuosas de electrolitos multicomponentes en el intervalo de fuerzas ionicas: 0 < 1 < 6 mol/Kg H{sub 2}O y temperaturas cercanas a 25 grados celsius) y su importancia a escala industrial. El calculo de las propiedades termodinamicas (coeficientes de actividad, coeficiente osmotico y actividad del agua) de la solucion, esta basado en una de las teorias mas modernas de los electrolitos; los resultados teoricos comparados con los experimentales tienen un error del 10% o mejor.

  2. Analytical and Experimental Performance Evaluation of BLE Neighbor Discovery Process Including Non-Idealities of Real Chipsets

    Directory of Open Access Journals (Sweden)

    David Perez-Diaz de Cerio

    2017-03-01

    Full Text Available The purpose of this paper is to evaluate from a real perspective the performance of Bluetooth Low Energy (BLE as a technology that enables fast and reliable discovery of a large number of users/devices in a short period of time. The BLE standard specifies a wide range of configurable parameter values that determine the discovery process and need to be set according to the particular application requirements. Many previous works have been addressed to investigate the discovery process through analytical and simulation models, according to the ideal specification of the standard. However, measurements show that additional scanning gaps appear in the scanning process, which reduce the discovery capabilities. These gaps have been identified in all of the analyzed devices and respond to both regular patterns and variable events associated with the decoding process. We have demonstrated that these non-idealities, which are not taken into account in other studies, have a severe impact on the discovery process performance. Extensive performance evaluation for a varying number of devices and feasible parameter combinations has been done by comparing simulations and experimental measurements. This work also includes a simple mathematical model that closely matches both the standard implementation and the different chipset peculiarities for any possible parameter value specified in the standard and for any number of simultaneous advertising devices under scanner coverage.

  3. New Flexible Models and Design Construction Algorithms for Mixtures and Binary Dependent Variables

    OpenAIRE

    Ruseckaite, Aiste

    2017-01-01

    markdownabstractThis thesis discusses new mixture(-amount) models, choice models and the optimal design of experiments. Two chapters of the thesis relate to the so-called mixture, which is a product or service whose ingredients’ proportions sum to one. The thesis begins by introducing mixture models in the choice context and develops new optimal design construction algorithms for choice experiments involving mixtures. Building further, varying the total amount of a mixture, and not only its i...

  4. Evaluation of the Stillinger-Weber classical interaction potential for tetragonal semiconductors in nonideal atomic configurations

    International Nuclear Information System (INIS)

    Dodson, B.W.

    1986-01-01

    A classical potential incorporating two- and three-body interaction terms has recently been introduced by Stillinger and Weber (SW) for simulation of the liquefaction transition of silicon. The equilibrium mechanical properties of this potential are determined and found to agree well with experimental values. The potential also seems to be adequate for problems involving computation of defect energies, such as the stability of strained-layer superlattice interfaces. However, inadequate treatment of configurations with low coordination number makes modeling of the epitaxial growth of (111) silicon impossible. Simple modifications of the SW potential form do allow for (111) epitaxial growth, but the earliest stages of growth then become unphysical

  5. Mixture based outlier filtration

    Czech Academy of Sciences Publication Activity Database

    Pecherková, Pavla; Nagy, Ivan

    2006-01-01

    Roč. 46, č. 2 (2006), s. 30-35 ISSN 1210-2709 R&D Projects: GA MŠk 1M0572; GA MDS 1F43A/003/120 Institutional research plan: CEZ:AV0Z10750506 Keywords : data filtration * system modelling * mixture models Subject RIV: BD - Theory of Information http://library.utia.cas.cz/prace/20060165.pdf

  6. Dynamic bounds for power and efficiency of non-ideal energy converters under nonlinear transfer laws

    International Nuclear Information System (INIS)

    Sieniutycz, Stanislaw

    2009-01-01

    We present a thermodynamic approach to simulation and modeling of nonlinear energy converters, in particular radiation engines. Novel results are obtained especially for dynamical engines when the temperature of the propelling medium decreases in time due to a continual decrease of the medium's internal energy caused by the power production. Basic thermodynamic principles determine the converter's efficiency and work limits in terms of the entropy production. The real work is a cumulative effect obtained in a system of a resource fluid, a sequence of engines, and an infinite bath. Nonlinear modeling involves dynamic optimization in which the classical expression for efficiency at maximum power is generalized to endoirreversible machines and nonlinear transfer laws. The primary result is a finite-rate generalization of the classical, reversible work potential (exergy). The generalized work function depends on thermal coordinates and a dissipation index, h, i.e. a Hamiltonian of the minimum entropy production problem. This generalized work function implies stronger bounds on work delivered or supplied than the reversible work potential. The role of the nonlinear analyses and dynamic optimization is shown especially for radiation engines. As an example of the kinetic work limit, generalized exergy of radiation fluid is estimated in terms of finite rates, quantified by the Hamiltonian h

  7. Mutual diffusion of binary liquid mixtures containing methanol, ethanol, acetone, benzene, cyclohexane, toluene, and carbon tetrachloride

    Energy Technology Data Exchange (ETDEWEB)

    Guevara-Carrion, Gabriela; Janzen, Tatjana; Muñoz-Muñoz, Y. Mauricio; Vrabec, Jadran, E-mail: jadran.vrabec@uni-paderborn.de [Thermodynamics and Energy Technology, University of Paderborn, 33098 Paderborn (Germany)

    2016-03-28

    Mutual diffusion coefficients of all 20 binary liquid mixtures that can be formed out of methanol, ethanol, acetone, benzene, cyclohexane, toluene, and carbon tetrachloride without a miscibility gap are studied at ambient conditions of temperature and pressure in the entire composition range. The considered mixtures show a varying mixing behavior from almost ideal to strongly non-ideal. Predictive molecular dynamics simulations employing the Green-Kubo formalism are carried out. Radial distribution functions are analyzed to gain an understanding of the liquid structure influencing the diffusion processes. It is shown that cluster formation in mixtures containing one alcoholic component has a significant impact on the diffusion process. The estimation of the thermodynamic factor from experimental vapor-liquid equilibrium data is investigated, considering three excess Gibbs energy models, i.e., Wilson, NRTL, and UNIQUAC. It is found that the Wilson model yields the thermodynamic factor that best suits the simulation results for the prediction of the Fick diffusion coefficient. Four semi-empirical methods for the prediction of the self-diffusion coefficients and nine predictive equations for the Fick diffusion coefficient are assessed and it is found that methods based on local composition models are more reliable. Finally, the shear viscosity and thermal conductivity are predicted and in most cases favorably compared with experimental literature values.

  8. Predicting the Solubility of Pharmaceutical Cocrystals in Solvent/Anti-Solvent Mixtures

    Directory of Open Access Journals (Sweden)

    Linda Lange

    2016-05-01

    Full Text Available In this work, the solubilities of pharmaceutical cocrystals in solvent/anti-solvent systems were predicted using PC-SAFT in order to increase the efficiency of cocrystal formation processes. Modeling results and experimental data were compared for the cocrystal system nicotinamide/succinic acid (2:1 in the solvent/anti-solvent mixtures ethanol/water, ethanol/acetonitrile and ethanol/ethyl acetate at 298.15 K and in the ethanol/ethyl acetate mixture also at 310.15 K. The solubility of the investigated cocrystal slightly increased when adding small amounts of anti-solvent to the solvent, but drastically decreased for high anti-solvent amounts. Furthermore, the solubilities of nicotinamide, succinic acid and the cocrystal in the considered solvent/anti-solvent mixtures showed strong deviations from ideal-solution behavior. However, by accounting for the thermodynamic non-ideality of the components, PC-SAFT is able to predict the solubilities in all above-mentioned solvent/anti-solvent systems in good agreement with the experimental data.

  9. Separating Underdetermined Convolutive Speech Mixtures

    DEFF Research Database (Denmark)

    Pedersen, Michael Syskind; Wang, DeLiang; Larsen, Jan

    2006-01-01

    a method for underdetermined blind source separation of convolutive mixtures. The proposed framework is applicable for separation of instantaneous as well as convolutive speech mixtures. It is possible to iteratively extract each speech signal from the mixture by combining blind source separation...

  10. Mixtures of truncated basis functions

    DEFF Research Database (Denmark)

    Langseth, Helge; Nielsen, Thomas Dyhre; Rumí, Rafael

    2012-01-01

    In this paper we propose a framework, called mixtures of truncated basis functions (MoTBFs), for representing general hybrid Bayesian networks. The proposed framework generalizes both the mixture of truncated exponentials (MTEs) framework and the mixture of polynomials (MoPs) framework. Similar...

  11. Computer simulation-molecular-thermodynamic framework to predict the micellization behavior of mixtures of surfactants: application to binary surfactant mixtures.

    Science.gov (United States)

    Iyer, Jaisree; Mendenhall, Jonathan D; Blankschtein, Daniel

    2013-05-30

    We present a computer simulation-molecular-thermodynamic (CSMT) framework to model the micellization behavior of mixtures of surfactants in which hydration information from all-atomistic simulations of surfactant mixed micelles and monomers in aqueous solution is incorporated into a well-established molecular-thermodynamic framework for mixed surfactant micellization. In addition, we address the challenges associated with the practical implementation of the CSMT framework by formulating a simpler mixture CSMT model based on a composition-weighted average approach involving single-component micelle simulations of the mixture constituents. We show that the simpler mixture CSMT model works well for all of the binary surfactant mixtures considered, except for those containing alkyl ethoxylate surfactants, and rationalize this finding molecularly. The mixture CSMT model is then utilized to predict mixture CMCs, and we find that the predicted CMCs compare very well with the experimental CMCs for various binary mixtures of linear surfactants. This paper lays the foundation for the mixture CSMT framework, which can be used to predict the micellization properties of mixtures of surfactants that possess a complex chemical architecture, and are therefore not amenable to traditional molecular-thermodynamic modeling.

  12. THERMODYNAMIC DEPRESSION OF IONIZATION POTENTIALS IN NONIDEAL PLASMAS: GENERALIZED SELF-CONSISTENCY CRITERION AND A BACKWARD SCHEME FOR DERIVING THE EXCESS FREE ENERGY

    International Nuclear Information System (INIS)

    Zaghloul, Mofreh R.

    2009-01-01

    Accurate and consistent prediction of thermodynamic properties is of great importance in high-energy density physics and in modeling stellar atmospheres and interiors as well. Modern descriptions of thermodynamic properties of such nonideal plasma systems are sophisticated and/or full of pitfalls that make it difficult, if not impossible, to reproduce. The use of the Saha equation modified at high densities by incorporating simple expressions for depression of ionization potentials is very convenient in that context. However, as it is commonly known, the incorporation of ad hoc or empirical expressions for the depression of ionization potentials in the Saha equation leads to thermodynamic inconsistencies. The problem of thermodynamic consistency of ionization potentials depression in nonideal plasmas is investigated and a criterion is derived, which shows immediately, whether a particular model for the ionization potential depression is self-consistent, that is, whether it can be directly related to a modification of the free-energy function, or not. A backward scheme is introduced which can be utilized to derive nonideality corrections to the free-energy function from formulas of ionization potentials depression derived from plasma microfields or in ad hoc or empirical fashion provided that the aforementioned self-consistency criterion is satisfied. The value and usefulness of such a backward method are pointed out and discussed. The above-mentioned criterion is applied to investigate the thermodynamic consistency of some historic models in the literature and an optional routine is introduced to recover their thermodynamic consistencies while maintaining the same functional dependence on the species densities as in the original models. Sample computational problems showing the effect of the proposed modifications on the computed plasma composition are worked out and presented.

  13. Separation of gas mixtures

    International Nuclear Information System (INIS)

    1981-01-01

    Apparatus is described for the separation of a gaseous plasma mixture into components in some of which the original concentration of a specific ion has been greatly increased or decreased, comprising: a source for converting the gaseous mixture into a train of plasma packets; an open-ended vessel with a main section and at least one branch section, adapted to enclose along predetermined tracks the original plasma packets in the main section, and the separated plasma components in the branch sections; drive means for generating travelling magnetic waves along the predetermined tracks with the magnetic flux vector of the waves transverse to each of the tracks; and means for maintaining phase coherence between the plasma packets and the magnetic waves at a value needed for accelerating the components of the packets to different velocities and in such different directions that the plasma of each packet is divided into distinctly separate packets in some of which the original concentration of a specific ion has been greatly increased or decreased, and which plasma packets are collected from the branch sections of the vessels. (author)

  14. Effect of non-ideal characteristics of an adder on the efficiency of data storage during scintillation radiometric testing with the use of pulse radiations

    International Nuclear Information System (INIS)

    Nedavnij, O.I.

    1983-01-01

    Problems of statistical summation of electric signals during scintillation radiometric control using pulse sources-betatrons and X-ray apparatus haVe been considered. Using calculation and experimental ways it is shown that non-ideal nature of adder, conditioned by energy consumption in the process of summation, hampers the information storage to a greater degree than in the case of difference of summed signals amplitudes with similar statistical weights. A new algorithm of television introscope operation, permitting to increase the efficiency of data storage is suggested

  15. Interparticle interactions and structure in nonideal solutions of human serum albumin studied by small-angle neutron scattering and Monte Carlo simulation

    DEFF Research Database (Denmark)

    Sjöberg, B.; Mortensen, K.

    1994-01-01

    Moderately or highly concentrated nonideal solutions of macromolecules are very important systems e.g. in biology and in many technical processes. In this work we have used the small-angle neutron scattering technique (SANS) to study the interactions and interparticle structure in solutions......(r). The advantage of using the Monte Carlo method is that completely general models for the particle shape and the interactions can be considered. It is found that the SANS data can be explained by a model where the shape of the HSA molecule is approximated by an ellipsoid of revolution with semiaxes a = 6.8 nm...

  16. Balancing Power Absorption and Structural Loading for a Novel Fixed-Bottom Wave Energy Converter with Nonideal Power Take-Off in Regular Waves: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Tom, Nathan M [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Yu, Yi-Hsiang [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Wright, Alan D [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2017-06-08

    In this work, the net power delivered to the grid from a nonideal power take-off (PTO) is introduced followed by a review of the pseudo-spectral control theory. A power-to-load ratio, used to evaluate the pseudo-spectral controller performance, is discussed, and the results obtained from optimizing a multiterm objective function are compared against results obtained from maximizing the net output power to the grid. Simulation results are then presented for four different oscillating wave energy converter geometries to highlight the potential of combing both geometry and PTO control to maximize power while minimizing loads.

  17. Research of Deformation of Clay Soil Mixtures Mixtures

    OpenAIRE

    Romas Girkontas; Tadas Tamošiūnas; Andrius Savickas

    2014-01-01

    The aim of this article is to determine clay soils and clay soils mixtures deformations during drying. Experiments consisted from: a) clay and clay mixtures bridges (height ~ 0,30 m, span ~ 1,00 m); b) tiles of clay and clay, sand and straw (height, length, wide); c) cylinders of clay; clay and straw; clay, straw and sand (diameter; height). According to the findings recommendations for clay and clay mixtures drying technology application were presented. During the experiment clay bridge bear...

  18. Inflation of the early cold Universe filled with a nonlinear scalar field and a nonideal relativistic Fermi gas

    Energy Technology Data Exchange (ETDEWEB)

    Pashitskii, E. A., E-mail: pashitsk@iop.kiev.ua; Pentegov, V. I., E-mail: pentegov@iop.kiev.ua [National Academy of Sciences of Ukraine, Institute of Physics (Ukraine)

    2017-03-15

    We consider a possible scenario for the evolution of the early cold Universe born from a fairly large quantum fluctuation in a vacuum with a size a{sub 0} ≫ l{sub P} (where l{sub P} is the Planck length) and filled with both a nonlinear scalar field φ, whose potential energy density U(φ) determines the vacuum energy density λ, and a nonideal Fermi gas with short-range repulsion between particles, whose equation of state is characterized by the ratio of pressure P(n{sub F}) to energy density ε(n{sub F}) dependent on the number density of fermions n{sub F}. As the early Universe expands, the dimensionless quantity ν(n{sub F}) = P(n{sub F})/ε(n{sub F}) decreases with decreasing n{sub F} from its maximum value ν{sub max} = 1 for n{sub F} → ∞ to zero for n{sub F} → 0. The interaction of the scalar and gravitational fields, which is characterized by a dimensionless constant ξ, is proportional to the scalar curvature of four-dimensional space R = κ[3P(n{sub F})–ε(n{sub F})–4λ] (where κ is Einstein’s gravitational constant), and contains terms both quadratic and linear in φ. As a result, the expanding early Universe reaches the point of first-order phase transition in a finite time interval at critical values of the scalar curvature R = R{sub c} =–μ{sup 2}/ξ and radius a{sub c} ≫ a{sub 0}. Thereafter, the early closed Universe “rolls down” from the flat inflection point of the potential U(φ) to the zero potential minimum in a finite time. The release of the total potential energy of the scalar field in the entire volume of the expanding Universe as it “rolls down” must be accompanied by the production of a large number of massive particles and antiparticles of various kinds, whose annihilation plays the role of the Big Bang. We also discuss the fundamental nature of Newton’ gravitational constant G{sub N}.

  19. Concomitant variables in finite mixture models

    NARCIS (Netherlands)

    Wedel, M

    The standard mixture model, the concomitant variable mixture model, the mixture regression model and the concomitant variable mixture regression model all enable simultaneous identification and description of groups of observations. This study reviews the different ways in which dependencies among

  20. Mutagenicity of complex mixtures

    International Nuclear Information System (INIS)

    Pelroy, R.A.

    1985-01-01

    The effect of coal-derived complex chemical mixtures on the mutagenicity of 6-aminochrysene (6-AC) was determined with Salmonella typhimurium TA98. Previous results suggested that the mutagenic potency of 6-AC for TA98 in the standard microsomal activation (Ames) assay increased if it was presented to the cells mixed with high-boiling coal liquids (CL) from the solvent refined coal (SRC) process. In this year's work, the apparent mutational synergism of CL and 6-AC was independently verified in a fluctuation bioassay which allowed quantitation of mutational frequencies and cell viability. The results of this assay system were similar to those in the Ames assay. Moreover, the fluctation assay revealed that mutagenesis and cellular toxicity induced by 6-AC were both strongly enhanced if 6-AC was presented to the cells mixed in a high-boiling CL. 4 figures

  1. Electrical properties of planar AlGaN/GaN Schottky diodes: Role of 2DEG and analysis of non-idealities

    Science.gov (United States)

    Persano, Anna; Pio, Iolanda; Tasco, Vittorianna; Cuscunà, Massimo; Passaseo, Adriana; Cola, Adriano

    2017-04-01

    A detailed study of the electrical properties of planar AlGaN/GaN Schottky diodes is presented, the focus being on the role of the two dimensional electron gas (2DEG) depletion and the diodes non-idealities in different voltage regimes. The 2DEG depletion behavior is inferred from the analysis of capacitance and current measurements with transition from vertical to lateral diode operation occurring at Vpinch-off = 4 V. In particular, the sub-micrometer depletion width, laterally extending from the edge of the Schottky contact under high reverse voltages, is evaluated on the basis of a simple fringe capacitance model. Current transport mechanisms are discussed, investigating the interrelation between 2DEG, Poole-Frenkel effect, and defects. With regard to defects, the role of dislocations in the AlGaN/GaN diode non-idealities, usually interpreted in terms of Schottky barrier inhomogeneities, is critically addressed. Photocurrent spatial mapping under high reverse voltage points out the not uniform electric field distribution around the Schottky contact and highlights the presence of local photo-conductive paths, likely associated with the dislocations near the edge of the Schottky contact.

  2. Comparisons of measurements and numerical simulations of a nonlinear beam subjected to a multi-harmonic non-ideal input signal

    International Nuclear Information System (INIS)

    Claeys, M.; Sinou, J.J.; Lambelin, J.P.; Alcoverro, B.

    2014-01-01

    This study presents a direct comparison of measured and predicted nonlinear vibrations of a clamped-clamped steel beam. A multi-harmonic comparison of simulations with measurements is performed at the vicinity of the primary resonance. First of all, a nonlinear analytical model of the beam is developed taking into account non-ideal boundary conditions. The Harmonic Balance Method is implemented to estimate the nonlinear behavior of the clamped-clamped beam. This nonlinear method enables to simulate the vibration stationary response of a nonlinear system projected on several harmonics. This study then proposes a method to compare numerical simulations with measurements on all these harmonics. A signal analysis tool is developed to extract the system harmonics' frequency responses from a temporal signal of a swept sine experiment. An evolutionary updating algorithm (Covariance Matrix Adaptation Evolution Strategy), coupled with highly selective filters is used to identify both fundamental frequency and harmonics' amplitude in the temporal signal, at every moment. This tool enables to extract the harmonic amplitudes of the output signal as well as the input signal. The input of the Harmonic Balance Method can then be either an ideal mono-harmonic signal or a multi-harmonic experimental input signal. Finally, the present work focuses on the comparison of experimental and simulated results. From experimental output harmonics and numerical simulations, it is shown that it is possible to distinguish the nonlinearities of the clamped-clamped beam and the effect of the non-ideal input signal. (authors)

  3. Neurotoxicity of Metal Mixtures.

    Science.gov (United States)

    Andrade, V M; Aschner, M; Marreilha Dos Santos, A P

    2017-01-01

    Metals are the oldest toxins known to humans. Metals differ from other toxic substances in that they are neither created nor destroyed by humans (Casarett and Doull's, Toxicology: the basic science of poisons, 8th edn. McGraw-Hill, London, 2013). Metals are of great importance in our daily life and their frequent use makes their omnipresence and a constant source of human exposure. Metals such as arsenic [As], lead [Pb], mercury [Hg], aluminum [Al] and cadmium [Cd] do not have any specific role in an organism and can be toxic even at low levels. The Substance Priority List of Agency for Toxic Substances and Disease Registry (ATSDR) ranked substances based on a combination of their frequency, toxicity, and potential for human exposure. In this list, As, Pb, Hg, and Cd occupy the first, second, third, and seventh positions, respectively (ATSDR, Priority list of hazardous substances. U.S. Department of Health and Human Services, Public Health Service, Atlanta, 2016). Besides existing individually, these metals are also (or mainly) found as mixtures in various parts of the ecosystem (Cobbina SJ, Chen Y, Zhou Z, Wub X, Feng W, Wang W, Mao G, Xu H, Zhang Z, Wua X, Yang L, Chemosphere 132:79-86, 2015). Interactions among components of a mixture may change toxicokinetics and toxicodynamics (Spurgeon DJ, Jones OAH, Dorne J-L, Svendsen C, Swain S, Stürzenbaum SR, Sci Total Environ 408:3725-3734, 2010) and may result in greater (synergistic) toxicity (Lister LJ, Svendsen C, Wright J, Hooper HL, Spurgeon DJ, Environ Int 37:663-670, 2011). This is particularly worrisome when the components of the mixture individually attack the same organs. On the other hand, metals such as manganese [Mn], iron [Fe], copper [Cu], and zinc [Zn] are essential metals, and their presence in the body below or above homeostatic levels can also lead to disease states (Annangi B, Bonassi S, Marcos R, Hernández A, Mutat Res 770(Pt A):140-161, 2016). Pb, As, Cd, and Hg can induce Fe, Cu, and Zn

  4. Complex mixtures biostudies

    International Nuclear Information System (INIS)

    Springer, D.L.

    1987-01-01

    The objective of the project is to identify potential adverse biological activities associated with human exposures to complex organic mixtures (COM) from energy-related industries. Studies to identify the influence of chemical class fractions from a COM on the initiating activity of a known carcinogen, benzo(a)pyrene (BaP), demonstrated that the polycyclic aromatic hydrocarbons (PAH) and nitrogen-containing polycyclic aromatic compound (NPAC) fractions were the most effective inhibitors of initiation. In an effort to determine the contribution of BaP to the initiating activity of the COM, binding of radiolabeled BaP to mouse skin DNA was measured. Results indicated that binding of BaP to DNA decreased in the presence of the COM so that at initiating COM doses, BaP binding was near the limit detection. Addition of unlabeled BaP to the COM at an amount similar to that originally present in the COM did not significantly increase the binding. Studies to determine the rates of disappearance of carcinogenic PAH from the site of application on the skin indicated that half-lives for PAH differed by a factor of about 2. Analytical methods developed to identify PAH from COM which covalently bind to DNA demonstrated that the lower level of detection is approximately 200 picograms. Developmental studies demonstrated that both pregnant rats and mice treated dermally with a high-boiling COM developed fetuses with major malformations including cleft palate, small lungs, edema, and sagittal suture hemorrhages. 3 figures, 5 tables

  5. Identification and separation of DNA mixtures using peak area information

    DEFF Research Database (Denmark)

    Cowell, R.G.; Lauritzen, Steffen Lilholt; Mortera, J.

    We show how probabilistic expert systems can be used to analyse forensic identification problems involving DNA mixture traces using quantitative peak area information. Peak area is modelled with conditional Gaussian distributions. The expert system can be used for scertaining whether individuals......, whose profiles have been measured, have contributed to the mixture, but also to predict DNA profiles of unknown contributors by separating the mixture into its individual components. The potential of our methodology is illustrated on case data examples and compared with alternative approaces...

  6. Lattice Boltzmann model for thermal binary-mixture gas flows.

    Science.gov (United States)

    Kang, Jinfen; Prasianakis, Nikolaos I; Mantzaras, John

    2013-05-01

    A lattice Boltzmann model for thermal gas mixtures is derived. The kinetic model is designed in a way that combines properties of two previous literature models, namely, (a) a single-component thermal model and (b) a multicomponent isothermal model. A comprehensive platform for the study of various practical systems involving multicomponent mixture flows with large temperature differences is constructed. The governing thermohydrodynamic equations include the mass, momentum, energy conservation equations, and the multicomponent diffusion equation. The present model is able to simulate mixtures with adjustable Prandtl and Schmidt numbers. Validation in several flow configurations with temperature and species concentration ratios up to nine is presented.

  7. Separation of organic azeotropic mixtures by pervaporation. Final technical report

    Energy Technology Data Exchange (ETDEWEB)

    Baker, R.W.

    1991-12-01

    Distillation is a commonly used separation technique in the petroleum refining and chemical processing industries. However, there are a number of potential separations involving azetropic and close-boiling organic mixtures that cannot be separated efficiently by distillation. Pervaporation is a membrane-based process that uses selective permeation through membranes to separate liquid mixtures. Because the separation process is not affected by the relative volatility of the mixture components being separated, pervaporation can be used to separate azetropes and close-boiling mixtures. Our results showed that pervaporation membranes can be used to separate azeotropic mixtures efficiently, a result that is not achievable with simple distillation. The membranes were 5--10 times more permeable to one of the components of the mixture, concentrating it in the permeate stream. For example, the membrane was 10 times more permeable to ethanol than methyl ethyl ketone, producing 60% ethanol permeate from an azeotropic mixture of ethanol and methyl ethyl ketone containing 18% ethanol. For the ethyl acetate/water mixture, the membranes showed a very high selectivity to water (> 300) and the permeate was 50--100 times enriched in water relative to the feed. The membranes had permeate fluxes on the order of 0.1--1 kg/m{sup 2}{center_dot}h in the operating range of 55--70{degrees}C. Higher fluxes were obtained by increasing the operating temperature.

  8. Thermophysical Properties of Hydrocarbon Mixtures

    Science.gov (United States)

    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.

  9. Easy and flexible mixture distributions

    DEFF Research Database (Denmark)

    Fosgerau, Mogens; Mabit, Stefan L.

    2013-01-01

    We propose a method to generate flexible mixture distributions that are useful for estimating models such as the mixed logit model using simulation. The method is easy to implement, yet it can approximate essentially any mixture distribution. We test it with good results in a simulation study...

  10. Nonlinearity of bituminous mixtures

    Science.gov (United States)

    Mangiafico, S.; Babadopulos, L. F. A. L.; Sauzéat, C.; Di Benedetto, H.

    2018-02-01

    This paper presents an experimental characterization of the strain dependency of the complex modulus of bituminous mixtures for strain amplitude levels lower than about 110 μm/m. A series of strain amplitude sweep tests are performed at different temperatures (8, 10, 12 and 14°C) and frequencies (0.3, 1, 3 and 10 Hz), during which complex modulus is monitored. For each combination of temperature and frequency, four maximum strain amplitudes are targeted (50, 75, 100 and 110 μm/m). For each of them, two series of 50 loading cycles are applied, respectively at decreasing and increasing strain amplitudes. Before each decreasing strain sweep and after each increasing strain sweep, 5 cycles are performed at constant maximum targeted strain amplitude. Experimental results show that the behavior of the studied material is strain dependent. The norm of the complex modulus decreases and phase angle increases with strain amplitude. Results are presented in Black and Cole-Cole plots, where characteristic directions of nonlinearity can be identified. Both the effects of nonlinearity in terms of the complex modulus variation and of the direction of nonlinearity in Black space seem to validate the time-temperature superposition principle with the same shift factors as for linear viscoelasticity. The comparison between results obtained during increasing and decreasing strain sweeps suggests the existence of another phenomenon occurring during cyclic loading, which appears to systematically induce a decrease of the norm of the complex modulus and an increase of the phase angle, regardless of the type of the strain sweep (increasing or decreasing).

  11. The Crystal-T algorithm: a new approach to calculate the SLE of lipidic mixtures presenting solid solutions.

    Science.gov (United States)

    Maximo, Guilherme J; Costa, Mariana C; Meirelles, Antonio J A

    2014-08-21

    Lipidic mixtures present a particular phase change profile highly affected by their unique crystalline structure. However, classical solid-liquid equilibrium (SLE) thermodynamic modeling approaches, which assume the solid phase to be a pure component, sometimes fail in the correct description of the phase behavior. In addition, their inability increases with the complexity of the system. To overcome some of these problems, this study describes a new procedure to depict the SLE of fatty binary mixtures presenting solid solutions, namely the "Crystal-T algorithm". Considering the non-ideality of both liquid and solid phases, this algorithm is aimed at the determination of the temperature in which the first and last crystal of the mixture melts. The evaluation is focused on experimental data measured and reported in this work for systems composed of triacylglycerols and fatty alcohols. The liquidus and solidus lines of the SLE phase diagrams were described by using excess Gibbs energy based equations, and the group contribution UNIFAC model for the calculation of the activity coefficients of both liquid and solid phases. Very low deviations of theoretical and experimental data evidenced the strength of the algorithm, contributing to the enlargement of the scope of the SLE modeling.

  12. Magnetogasdynamics shock waves in a rotational axisymmetric non-ideal gas with increasing energy and conductive and radiative heat-fluxes

    Science.gov (United States)

    Nath, Gorakh

    2016-07-01

    Self-similar solutions are obtained for one-dimensional adiabatic flow behind a magnetogasdynamics cylindrical shock wave propagating in a rotational axisymmetric non ideal gas with increasing energy and conductive and radiative heat fluxes in presence of an azimuthal magnetic field. The fluid velocities and the azimuthal magnetic field in the ambient medium are assume to be varying and obeying power laws. In order to find the similarity solutions the angular velocity of the ambient medium is taken to be decreasing as the distance from the axis increases. The heat conduction is expressed in terms of Fourier's law and the radiation is considered to be the diffusion type for an optically thick grey gas model. The thermal conductivity and the absorption coefficient are assumed to vary with temperature and density. The effects of the presence of radiation and conduction, the non-idealness of the gas and the magnetic field on the shock propagation and the flow behind the shock are investigated.

  13. Evaluation of superpave mixtures containing hydrated lime.

    Science.gov (United States)

    2013-07-01

    The use of hydrated lime in Hot-Mix Asphalt (HMA) mixtures can reduce permanent deformation, long-term aging, and moisture : susceptibility of mixtures. In addition, hydrated lime increases the stiffness and fatigue resistance of mixtures. This study...

  14. Performance evaluation of Louisiana superpave mixtures.

    Science.gov (United States)

    2008-12-01

    This report documents the performance of Louisiana Superpave mixtures through laboratory mechanistic tests, mixture : volumetric properties, gradation analysis, and early field performance. Thirty Superpave mixtures were evaluated in this : study. Fo...

  15. A dangerous mixture

    Directory of Open Access Journals (Sweden)

    Anna Piva

    2014-03-01

    Full Text Available A 59-year old woman was admitted for fatigue and arm paresthesias with Trousseau sign. Her medical history included thyroidectomy and hypercholesterolemia recently treated with simvastatin. Laboratory tests showed severe hypokalemia and hypocalcemia, severe increase in muscle enzymes, metabolic alkalosis; low plasma renin activity, increased thyroid-stimulating hormone, normal free thyroxine, increased parathyroid hormone, decreased vitamin D3; alterations in electrolyte urinary excretion, cortisol and aldosterone were excluded. Hypothesizing a statin-related myopathy, simvastatin was suspended; the patient reported use of laxatives containing licorice. Electrolytes normalized with intravenous supplementation. Among many biochemical alterations, none stands out as a major cause for muscular and electrolyte disorders. All co-factors are inter-connected, starting with statin-induced myopathy, worsened by hypothyroidism, secondary hyperaldosteronism and vitamin D deficiency, leading to hypocalcemia and hypokalemia, perpetrating muscular and electrolyte disorders. The importance of considering clinical conditions as a whole emerges with multiple co-factors involved. Another issue concerns herbal products and their potential dangerous effects.

  16. Nonparametric e-Mixture Estimation.

    Science.gov (United States)

    Takano, Ken; Hino, Hideitsu; Akaho, Shotaro; Murata, Noboru

    2016-12-01

    This study considers the common situation in data analysis when there are few observations of the distribution of interest or the target distribution, while abundant observations are available from auxiliary distributions. In this situation, it is natural to compensate for the lack of data from the target distribution by using data sets from these auxiliary distributions-in other words, approximating the target distribution in a subspace spanned by a set of auxiliary distributions. Mixture modeling is one of the simplest ways to integrate information from the target and auxiliary distributions in order to express the target distribution as accurately as possible. There are two typical mixtures in the context of information geometry: the [Formula: see text]- and [Formula: see text]-mixtures. The [Formula: see text]-mixture is applied in a variety of research fields because of the presence of the well-known expectation-maximazation algorithm for parameter estimation, whereas the [Formula: see text]-mixture is rarely used because of its difficulty of estimation, particularly for nonparametric models. The [Formula: see text]-mixture, however, is a well-tempered distribution that satisfies the principle of maximum entropy. To model a target distribution with scarce observations accurately, this letter proposes a novel framework for a nonparametric modeling of the [Formula: see text]-mixture and a geometrically inspired estimation algorithm. As numerical examples of the proposed framework, a transfer learning setup is considered. The experimental results show that this framework works well for three types of synthetic data sets, as well as an EEG real-world data set.

  17. Modeling and analysis of personal exposures to VOC mixtures using copulas

    Science.gov (United States)

    Su, Feng-Chiao; Mukherjee, Bhramar; Batterman, Stuart

    2014-01-01

    Environmental exposures typically involve mixtures of pollutants, which must be understood to evaluate cumulative risks, that is, the likelihood of adverse health effects arising from two or more chemicals. This study uses several powerful techniques to characterize dependency structures of mixture components in personal exposure measurements of volatile organic compounds (VOCs) with aims of advancing the understanding of environmental mixtures, improving the ability to model mixture components in a statistically valid manner, and demonstrating broadly applicable techniques. We first describe characteristics of mixtures and introduce several terms, including the mixture fraction which represents a mixture component's share of the total concentration of the mixture. Next, using VOC exposure data collected in the Relationship of Indoor Outdoor and Personal Air (RIOPA) study, mixtures are identified using positive matrix factorization (PMF) and by toxicological mode of action. Dependency structures of mixture components are examined using mixture fractions and modeled using copulas, which address dependencies of multiple variables across the entire distribution. Five candidate copulas (Gaussian, t, Gumbel, Clayton, and Frank) are evaluated, and the performance of fitted models was evaluated using simulation and mixture fractions. Cumulative cancer risks are calculated for mixtures, and results from copulas and multivariate lognormal models are compared to risks calculated using the observed data. Results obtained using the RIOPA dataset showed four VOC mixtures, representing gasoline vapor, vehicle exhaust, chlorinated solvents and disinfection by-products, and cleaning products and odorants. Often, a single compound dominated the mixture, however, mixture fractions were generally heterogeneous in that the VOC composition of the mixture changed with concentration. Three mixtures were identified by mode of action, representing VOCs associated with hematopoietic, liver

  18. Ambiguous involvement

    DEFF Research Database (Denmark)

    Dannesboe, Karen Ida

    2016-01-01

    This edited collection shows that good parenthood is neither fixed nor stable. The contributors show how parenthood is equally done by men, women and children, in and through practices involving different normative guidelines. The book explores how normative layers of parenthood are constituted...... by notions such as good childhood, family ideals, national public health and educational strategies. The authors illustrate how different versions of parenthood coexist and how complex sets of actions are demanded to fulfil today’s expectations of parenthood in Western societies. This interdisciplinary book...

  19. Mixtures of skewed Kalman filters

    KAUST Repository

    Kim, Hyoungmoon

    2014-01-01

    Normal state-space models are prevalent, but to increase the applicability of the Kalman filter, we propose mixtures of skewed, and extended skewed, Kalman filters. To do so, the closed skew-normal distribution is extended to a scale mixture class of closed skew-normal distributions. Some basic properties are derived and a class of closed skew. t distributions is obtained. Our suggested family of distributions is skewed and has heavy tails too, so it is appropriate for robust analysis. Our proposed special sequential Monte Carlo methods use a random mixture of the closed skew-normal distributions to approximate a target distribution. Hence it is possible to handle skewed and heavy tailed data simultaneously. These methods are illustrated with numerical experiments. © 2013 Elsevier Inc.

  20. Bayesian Kernel Mixtures for Counts.

    Science.gov (United States)

    Canale, Antonio; Dunson, David B

    2011-12-01

    Although Bayesian nonparametric mixture models for continuous data are well developed, there is a limited literature on related approaches for count data. A common strategy is to use a mixture of Poissons, which unfortunately is quite restrictive in not accounting for distributions having variance less than the mean. Other approaches include mixing multinomials, which requires finite support, and using a Dirichlet process prior with a Poisson base measure, which does not allow smooth deviations from the Poisson. As a broad class of alternative models, we propose to use nonparametric mixtures of rounded continuous kernels. An efficient Gibbs sampler is developed for posterior computation, and a simulation study is performed to assess performance. Focusing on the rounded Gaussian case, we generalize the modeling framework to account for multivariate count data, joint modeling with continuous and categorical variables, and other complications. The methods are illustrated through applications to a developmental toxicity study and marketing data. This article has supplementary material online.

  1. Preparation of conducting solid mixtures

    International Nuclear Information System (INIS)

    Spokas, J.J.

    1978-01-01

    The application of conducting plastic mixtures to the fundamental problem of radiation dosimetry is briefly reviewed. A particular approach to achieving formulations with the necessary characteristics is described. A number of successful mixtures are defined for a number of different specific dosimetry situations. To obtain high quality stable materials requires intense blending and working of the materials at elevated temperatures. One machine that succeeds in this task is the Shonka plastics mixer-extruder. The Shonka mixer is described in complete detail. The procedures used in preparing representative formulations with this device are presented. A number of properties of successful conducting mixtures so prepared are summarized. The conditions required for molding such material are given. Several special welding methods for specific application with these formulations have been devised and are described

  2. 16 CFR 1500.5 - Hazardous mixtures.

    Science.gov (United States)

    2010-01-01

    ... 16 Commercial Practices 2 2010-01-01 2010-01-01 false Hazardous mixtures. 1500.5 Section 1500.5... HAZARDOUS SUBSTANCES AND ARTICLES; ADMINISTRATION AND ENFORCEMENT REGULATIONS § 1500.5 Hazardous mixtures. For a mixture of substances, the determination of whether the mixture is a “hazardous substance” as...

  3. D- and I-optimal design of mixture experiments in the presence of ingredient availability constraints

    OpenAIRE

    SYAFITRI, Utami; SARTONO, Bagus; GOOS, Peter

    2015-01-01

    Mixture experiments usually involve various constraints on the proportions of the ingredients of the mixture under study. In this paper, inspired by the fact that the available stock of certain ingredients is often limited, we focus on a new type of constraint, which we refer to as an ingredient availability constraint. This type of constraint substantially complicates the search for optimal designs for mixture experiments. One difficulty, for instance, is that the optimal number of experimen...

  4. Xe-containing fast gas mixtures for gas-filled detectors

    International Nuclear Information System (INIS)

    Christophorou, L.G.; McCorkle, D.L.; Oak Ridge National Lab., TN; Maxey, D.V.; Carter, J.G.

    1980-01-01

    Electron drift velocities are reported for Xe-CF 4 , Xe-C 2 H 2 and Xe-CF 4 -C 2 H 2 mixtures. For a number of these mixtures the drift velocities are large (4 to 10 x 10 6 cm s -1 ) over a range of E/P values below 3.5 V cm -1 Torr -1 . Such mixtures may find application in gas-filled detectors, especially those involving electromagnetic ionizing radiation. (orig.)

  5. Computational fluid dynamic simulation of axial and radial flow membrane chromatography: mechanisms of non-ideality and validation of the zonal rate model.

    Science.gov (United States)

    Ghosh, Pranay; Vahedipour, Kaveh; Lin, Min; Vogel, Jens H; Haynes, Charles; von Lieres, Eric

    2013-08-30

    Membrane chromatography (MC) is increasingly being used as a purification platform for large biomolecules due to higher operational flow rates. The zonal rate model (ZRM) has previously been applied to accurately characterize the hydrodynamic behavior in commercial MC capsules at different configurations and scales. Explorations of capsule size, geometry and operating conditions using the model and experiment were used to identify possible causes of inhomogeneous flow and their contributions to band broadening. In the present study, the hydrodynamics within membrane chromatography capsules are more rigorously investigated by computational fluid dynamics (CFD). The CFD models are defined according to precisely measured capsule geometries in order to avoid the estimation of geometry related model parameters. In addition to validating the assumptions and hypotheses regarding non-ideal flow mechanisms encoded in the ZRM, we show that CFD simulations can be used to mechanistically understand and predict non-binding breakthrough curves without need for estimation of any parameters. When applied to a small-scale axial flow MC capsules, CFD simulations identify non-ideal flows in the distribution (hold-up) volumes upstream and downstream of the membrane stack as the major source of band broadening. For the large-scale radial flow capsule, the CFD model quantitatively predicts breakthrough data using binding parameters independently determined using the small-scale axial flow capsule, identifying structural irregularities within the membrane pleats as an important source of band broadening. The modeling and parameter determination scheme described here therefore facilitates a holistic mechanistic-based method for model based scale-up, obviating the need of performing expensive large-scale experiments under binding conditions. As the CFD model described provides a rich mechanistic analysis of membrane chromatography systems and the ability to explore operational space, but

  6. Ecological Assembly of Chemical Mixtures

    Science.gov (United States)

    Human-environment interactions have a significant role in the formation of chemical mixtures in the environment and by extension in human tissues and fluids. These interactions, which include decisions to purchase and use products containing chemicals as well as behaviors and act...

  7. Characterization of bioactive mixtures oligogalacturonidos

    International Nuclear Information System (INIS)

    Mederos Torres, Yuliem; Hormaza Montenegro, Josefa; Reynaldo Escobar, Ines; Montesino Sequi, Raquel

    2011-01-01

    Oligogalacturonides are pectic oligosaccharides composed of lineal chains of D-galacturonic acid, linked by α (1-4) glycosidic linkage. Oligogalacturonides' mixtures are obtained by enzymatic hydrolysis of pectins of diverse vegetal species. These oligosaccharides unchain a diverse biological activity in plants, which depends mainly on their polymerization degrees. The National Institute of Agricultural Science has a patent technology at national scale that lets to obtain a mixture of oligogalacturonides with different polymerization degree. In this work is presented the characterization of oligogalacturonides by spectrophotometric analysis attending to their uronic acids, reductor sugars, and neutral sugars content. Also the chromatographic profile of samples in study is obtained, using the derivatization with 2-aminobenzamide label and the separation by high pH anion exchange chromatography. It is achieved the separation of at least eight galacturonic acid oligomers with a variable degree of polymerization. On the other hand, the analysis by Fourier transform-infrared spectroscopy (FT-IR) showed that mixtures were composed by galacturonic acid salts. Results indicated that starting from two pectic acids with different characteristics, mixtures of oligogalacturonides of similar chemical composition could be obtained, but they differ in the proportion that they are presented

  8. hydrocarbon mixtures: Phase strength analysis

    Indian Academy of Sciences (India)

    Unknown

    In case of each type of binary mixture, there were five samples with different molar ratio (MR) ... Philips X-ray diffractometer, type PW1710. The operating conditions were: 25 mA current at 40 kV potential; Co- ..... ned only as a dream of the authors. The authors are since- rely thankful to Dr D Banerjee, Director, Defence.

  9. Afrikaner spirituality: A complex mixture

    African Journals Online (AJOL)

    UPuser

    Afrikaner spirituality: A complex mixture. Erna Oliver. Department of Christian Spirituality. Church History and Missiology. University of South Africa. Abstract. The article argues that the perception that Afrikaner spirituality is and has always been founded mainly or only upon the Calvinistic tradition is a misconception.

  10. Topological skeleton of the 2-D slightly non-ideal MHD system close to X-type magnetic null points – an analysis of the general solution for the generic case

    Directory of Open Access Journals (Sweden)

    D. H. Nickeler

    2012-06-01

    Full Text Available The appearance of eruptive space plasma processes, e.g. in eruptive flares as observed in the solar atmosphere, is usually assumed to be caused by magnetic reconnection, often connected with singular points of the magnetic field. We are interested in the general relation between the eigenvalues of the Jacobians of the plasma velocity and the magnetic field and their relation to the shape of a spatially varying, localized non-idealness or resistivity, i.e. we are searching for the general solution. We perform a local analysis of almost all regular, generic, structurally stable non-ideal or resistive MHD solutions. Therefore we use Taylor expansions of the magnetic field, the velocity field and all other physical quantities, including the non-idealness, and with the method of comparison of coefficients, the non-linear resistive MHD system is solved analytically, locally in a close vicinity of the null point. We get a parameterised general solution that provides us with the topological and geometrical skeleton of the resistive MHD fields. These local solutions provide us with the "roots" of field and streamlines around the null points of basically all possible 2-D reconnection solutions. We prove mathematically that necessarily, the flow close to the magnetic X-point must also be of X-point type to guarantee positive dissipation of energy and annihilation of magnetic flux. We also prove that, if the non-idealness has only a one-dimensional, sheet-like structure, only one separatrix line can be crossed by the plasma flow, similar to known reconnective annihilation solutions.

  11. UV-Vis spectroscopic study and DFT calculation on the solvent effect of trimethoprim in neat solvents and aqueous mixtures.

    Science.gov (United States)

    Almandoz, M C; Sancho, M I; Duchowicz, P R; Blanco, S E

    2014-08-14

    The solvatochromic behavior of trimethoprim (TMP) was analyzed using UV-Vis spectroscopy and DFT methods in neat and binary aqueous solvent mixtures. The effects of solvent dipolarity/polarizability and solvent-solute hydrogen bonding interactions on the absorption maxima were evaluated by means of the linear solvation energy relationship concept of Kamlet and Taft. This analysis indicated that both interactions play an important role in the position of the absorption maxima in neat solvents. The simulated absorption spectra of TMP and TMP:(solvent)n complexes in ACN and H2O using TD-DFT methods were in agreement with the experimental ones. Binary aqueous mixtures containing as co-solvents DMSO, ACN and EtOH were studied. Preferential solvation was detected as a nonideal behavior of the wavenumber curve respective to the analytical mole fraction of co-solvent in all binary systems. TMP molecules were preferentially solvated by the organic solvent over the whole composition range. Index of preferential solvation, as well as the influence of solvent parameters were calculated as a function of solvent composition. Copyright © 2014 Elsevier B.V. All rights reserved.

  12. Effect of gasoline diesel fuel mixture on the germination and the ...

    African Journals Online (AJOL)

    The effects of gasoline fuel/diesel mixture on the germination of seeds of Vigna unguiculata, the survival of the seedlings and the growth of the plant were evaluated in this study. It involved adding 10, 20, 30, 40 and 50 ml of mixture of equal proportions of the two petroleum products to 5000 g of soil and sowing seeds of the ...

  13. An NCME Instructional Module on Latent DIF Analysis Using Mixture Item Response Models

    Science.gov (United States)

    Cho, Sun-Joo; Suh, Youngsuk; Lee, Woo-yeol

    2016-01-01

    The purpose of this ITEMS module is to provide an introduction to differential item functioning (DIF) analysis using mixture item response models. The mixture item response models for DIF analysis involve comparing item profiles across latent groups, instead of manifest groups. First, an overview of DIF analysis based on latent groups, called…

  14. Toxicity of Flare and Crude Hydrocarbon Mixtures

    Directory of Open Access Journals (Sweden)

    Sonja V. Cook

    2002-01-01

    Full Text Available The toxicity of whole, saturate, and aromatic hydrocarbon mixtures from flare pit and crude oil sources were evaluated using Lumbricus terrestris. Body burden analysis was used to analyze the intrinsic toxicity of the six hydrocarbon mixtures. The major fractions of the whole mixtures, the saturate, and aromatic fractions had different intrinsic toxicities; the aromatics were more toxic than the saturates. The toxicity of the saturate and aromatic fractions also differed between the mixtures. The flare saturate mixture was more toxic than the crude saturate mixture, while the crude aromatic mixture was more toxic than the flare aromatic mixture. The most dramatic difference in toxicity of the two sources was between the flare whole and crude whole mixtures. The crude whole mixture was very toxic; the toxicity of this mixture reflected the toxicity of the crude aromatic fraction. However, the flare whole mixture was not toxic, due to a lack of partitioning from the whole mixture into the lipid membrane of the exposed worms. This lack of partitioning appears to be related to the relatively high concentrations of asphaltenes and polar compounds in the flare pit whole mixture.

  15. Balancing the Power-to-Load Ratio for a Novel Variable Geometry Wave Energy Converter with Nonideal Power Take-Off in Regular Waves: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Tom, Nathan M [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Yu, Yi-Hsiang [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Wright, Alan D [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2017-09-28

    This work attempts to balance power absorption against structural loading for a novel variable geometry wave energy converter. The variable geometry consists of four identical flaps that will be opened in ascending order starting with the flap closest to the seafloor and moving to the free surface. The influence of a pitch motion constraint on power absorption when utilizing a nonideal power take-off (PTO) is examined and found to reduce the losses associated with bidirectional energy flow. The power-to-load ratio is evaluated using pseudo-spectral control to determine the optimum PTO torque based on a multiterm objective function. The pseudo-spectral optimal control problem is extended to include load metrics in the objective function, which may now consist of competing terms. Separate penalty weights are attached to the surge-foundation force and PTO control torque to tune the optimizer performance to emphasize either power absorption or load shedding. PTO efficiency is not included in the objective function, but the penalty weights are utilized to limit the force and torque amplitudes, thereby reducing losses associated with bidirectional energy flow. Results from pseudo-spectral control demonstrate that shedding a portion of the available wave energy can provide greater reductions in structural loads and reactive power.

  16. Capture rate and efficiency of an oscillating non-ideal trap interacting with a sea of random diffusing particles. A non-equilibrium Fokker–Planck picture

    Energy Technology Data Exchange (ETDEWEB)

    Grassi, A., E-mail: agrassi@unict.it [Dipartimento di Scienze del Farmaco, v.le A. Doria 6, Università di Catania, 95125 Catania (Italy); Lombardo, G.M. [Dipartimento di Scienze del Farmaco, v.le A. Doria 6, Università di Catania, 95125 Catania (Italy); Pannuzzo, M., E-mail: martina.pannuzzo@gmail.com [Department of Computational Biology, University of Erlangen-Nuremberg, Staudtstrasse 5, 91058 Erlangen (Germany); Raudino, A., E-mail: araudino@dipchi.unict.it [Dipartimento di Scienze Chimiche, v.le A. Doria 6, Università di Catania, 95125 Catania (Italy)

    2015-02-06

    Highlights: • We analyzed the particles dynamics subject to an oscillating “trap”. • Numerical solution to FPE with various trap's oscillating frequencies and amplitudes. • Out-of-equilibrium calculations describe the evolution toward a “pseudo” equilibrium state. • At pseudo-equilibrium state trapped particles density depends on frequency and amplitude. - Abstract: We investigated the time evolution of a distribution of random diffusing particles around an oscillating non-ideal trap. The problem has been addressed by numerically solving a mono-dimensional Fokker–Planck equation (FPE) for a confined distribution of particles in the presence of an oscillating potential well (trap) of finite depth. Accurate numerical solutions of the FPE have been obtained and expressed as a function of the trap oscillation amplitudes and frequencies. Results show a marked influence of the oscillations both on the capture kinetics and trap efficiency in equilibrium conditions. All the calculated properties exhibit a saturation behavior both at high and low frequencies.

  17. A new decomposition-based computer-aided molecular/mixture design methodology for the design of optimal solvents and solvent mixtures

    DEFF Research Database (Denmark)

    Karunanithi, A.T.; Achenie, L.E.K.; Gani, Rafiqul

    2005-01-01

    This paper presents a novel computer-aided molecular/mixture design (CAMD) methodology for the design of optimal solvents and solvent mixtures. The molecular/mixture design problem is formulated as a mixed integer nonlinear programming (MINLP) model in which a performance objective is to be optim......This paper presents a novel computer-aided molecular/mixture design (CAMD) methodology for the design of optimal solvents and solvent mixtures. The molecular/mixture design problem is formulated as a mixed integer nonlinear programming (MINLP) model in which a performance objective...... is to be optimized subject to structural, property, and process constraints. The general molecular/mixture design problem is divided into two parts. For optimal single-compound design, the first part is solved. For mixture design, the single-compound design is first carried out to identify candidates...... and then the second part is solved to determine the optimal mixture. The decomposition of the CAMD MINLP model into relatively easy to solve subproblems is essentially a partitioning of the constraints from the original set. This approach is illustrated through two case studies. The first case study involves...

  18. Mixtures in nonstable Levy processes

    International Nuclear Information System (INIS)

    Petroni, N Cufaro

    2007-01-01

    We analyse the Levy processes produced by means of two interconnected classes of nonstable, infinitely divisible distribution: the variance gamma and the Student laws. While the variance gamma family is closed under convolution, the Student one is not: this makes its time evolution more complicated. We prove that-at least for one particular type of Student processes suggested by recent empirical results, and for integral times-the distribution of the process is a mixture of other types of Student distributions, randomized by means of a new probability distribution. The mixture is such that along the time the asymptotic behaviour of the probability density functions always coincide with that of the generating Student law. We put forward the conjecture that this can be a general feature of the Student processes. We finally analyse the Ornstein-Uhlenbeck process driven by our Levy noises and show a few simulations of it

  19. Malabsorption of fructose-sorbitol mixtures. Interactions causing abdominal distress

    DEFF Research Database (Denmark)

    Rumessen, J J; Gudmand-Høyer, E

    1987-01-01

    Hydrogen breath tests were performed on 10 healthy adults after they had ingested a mixture of sorbitol and fructose, in which these substances were present in amounts corresponding to the individual absorption capacities. A significant malabsorption of this mixture was evident in 7 of 10 subjects......, but given as sucrose, and a similar amount of sorbitol was further given to four of the seven subjects showing malabsorption of the fructose-sorbitol mixture. Malabsorption now failed to appear, and symptoms were absent. These findings are of potential importance for the understanding of the physiologic...... processes involved in fructose absorption and suggest that in healthy adults the presence of sorbitol interferes with fructose absorption and/or vice versa. An interaction between small amounts of fructose and sorbitol causing malabsorption and abdominal distress has not been demonstrated previously...

  20. Effects of laboratory heating, cyclic pore pressure, and cyclic loading on fracture properties of asphalt mixture.

    Science.gov (United States)

    2012-04-01

    This study involved the identification and evaluation of laboratory conditioning methods and testing protocols considering heat oxidation, moisture, and load that more effectively simulate asphalt mixture aging in the field, and thereby help to prope...

  1. Dietary fiber mixture in pediatric patients with controlled chronic constipation.

    Science.gov (United States)

    Weber, Thabata K; Toporovski, Mauro S; Tahan, Soraia; Neufeld, Clarice B; de Morais, Mauro B

    2014-03-01

    The aim of the study was to test the clinical efficacy and effect on colonic transit time (CTT) of a dietary fiber mixture given to children with controlled chronic constipation (CC) after the withdrawal of stool softeners and enemas. This randomized, placebo-controlled, double-blind clinical trial involved 54 patients aged 4 to 12 years and had CC that was controlled by the use of low-dose stool softeners. The use of these softeners was discontinued when the patients were admitted to the clinical trial. The patients were randomized into 2 groups for the 4-week study period. One group received a dietary fiber mixture and the other group received a placebo (maltodextrin). The primary outcome was therapeutic failure (oral stool softeners or enemas was required to prescribe during the trial). Secondary outcomes included defecation frequency, stool consistency (measured using the Bristol Stool Form Scale), and CTT. Therapeutic failure was observed in 34.6% (9/26) of the patients in the dietary fiber mixture group and in 35.7% (10/28) in the control group (P = 0.933). The mean increase in daily bowel movements was 0.53 in the dietary fiber mixture group and 0.23 in the control group (P = 0.014). The patients in the dietary fiber mixture group (60.0%) passed nonhardened stools more frequently than did those in the control group (16.7%, P = 0.003). The CTT was similar for both groups. The fiber mixture did not prevent the suspension of stool softeners or lead to reduced CTT; however, the mixture promoted an increased frequency of defecation and an improvement in the stool consistency.

  2. On theoretical aspects of mixture problems

    Directory of Open Access Journals (Sweden)

    François Dubeau

    2017-11-01

    Full Text Available Mixture problems are basic but important problems in Operations Research. In this paper we consider variants of the basic linear mixture problem and indicate mathematical links between them.

  3. Properties of asphalt mixtures containing RAP.

    Science.gov (United States)

    2009-12-01

    A typical NHDOT Hot Mix Asphalt (HMA) concrete mixture contains at least 15% Reclaimed Asphalt Pavement (RAP). The increasing cost of virgin asphalt and aggregate has increased the interest in using higher percentages of RAP in HMA mixtures. The purp...

  4. Evaluation of HMA mixtures containing Sasobit.

    Science.gov (United States)

    2009-07-01

    This limited study provided a laboratory and field comparative evaluation of PG 76-22 HMA : hot mix asphalt (HMA) mixture and a mixture containing the additive Sasobit. The : fundamental material characterization testing (asphalt cement binde...

  5. A Statistical Approach to Optimizing Concrete Mixture Design

    Science.gov (United States)

    Alghamdi, Saeid A.

    2014-01-01

    A step-by-step statistical approach is proposed to obtain optimum proportioning of concrete mixtures using the data obtained through a statistically planned experimental program. The utility of the proposed approach for optimizing the design of concrete mixture is illustrated considering a typical case in which trial mixtures were considered according to a full factorial experiment design involving three factors and their three levels (33). A total of 27 concrete mixtures with three replicates (81 specimens) were considered by varying the levels of key factors affecting compressive strength of concrete, namely, water/cementitious materials ratio (0.38, 0.43, and 0.48), cementitious materials content (350, 375, and 400 kg/m3), and fine/total aggregate ratio (0.35, 0.40, and 0.45). The experimental data were utilized to carry out analysis of variance (ANOVA) and to develop a polynomial regression model for compressive strength in terms of the three design factors considered in this study. The developed statistical model was used to show how optimization of concrete mixtures can be carried out with different possible options. PMID:24688405

  6. Consistency of the MLE under mixture models

    OpenAIRE

    Chen, Jiahua

    2016-01-01

    The large-sample properties of likelihood-based statistical inference under mixture models have received much attention from statisticians. Although the consistency of the nonparametric MLE is regarded as a standard conclusion, many researchers ignore the precise conditions required on the mixture model. An incorrect claim of consistency can lead to false conclusions even if the mixture model under investigation seems well behaved. Under a finite normal mixture model, for instance, the consis...

  7. Dirichlet Process Parsimonious Mixtures for clustering

    OpenAIRE

    Chamroukhi, Faicel; Bartcus, Marius; Glotin, Hervé

    2015-01-01

    The parsimonious Gaussian mixture models, which exploit an eigenvalue decomposition of the group covariance matrices of the Gaussian mixture, have shown their success in particular in cluster analysis. Their estimation is in general performed by maximum likelihood estimation and has also been considered from a parametric Bayesian prospective. We propose new Dirichlet Process Parsimonious mixtures (DPPM) which represent a Bayesian nonparametric formulation of these parsimonious Gaussian mixtur...

  8. Psychophysical studies of mixtures of tastants

    NARCIS (Netherlands)

    Graaf, de C.

    1988-01-01

    The human perception of mixtures of tastante was studied with reference to three central issues, i.e., 1) the paradigma of equiratio taste substance mixtures. as an instrument to manipulate the physical composition of tastant mixtures. This paradiama also enables the construction of psychophysical

  9. 21 CFR 82.6 - Certifiable mixtures.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Certifiable mixtures. 82.6 Section 82.6 Food and... PROVISIONALLY LISTED COLORS AND SPECIFICATIONS General Provisions § 82.6 Certifiable mixtures. (a) A batch of a mixture which contains no straight color listed in subpart C or D may be certified for use in food, drugs...

  10. Some properties of explosive mixtures containing peroxides

    International Nuclear Information System (INIS)

    Zeman, Svatopluk; Trzcinski, Waldemar A.; Matyas, Robert

    2008-01-01

    This study concerns mixtures of triacetone triperoxide (3,3,6,6,9,9-hexamethyl-1,2,4,5,7,8-hexoxonane, TATP) and ammonium nitrate (AN) with added water (W), as the case may be, and dry mixtures of TATP with urea nitrate (UN). Relative performances (RP) of the mixtures and their individual components, relative to TNT, were determined by means of ballistic mortar. The detonation energies, E 0 , and detonation velocities, D, were calculated for the mixtures studied by means of the thermodynamic code CHEETAH. Relationships have been found and are discussed between the RP and the E 0 values related to unit volume of gaseous products of detonation of these mixtures. These relationships together with those between RP and oxygen balance values of the mixtures studied indicate different types of participation of AN and UN in the explosive decomposition of the respective mixtures. Dry TATP/UN mixtures exhibit lower RP than analogous mixtures TATP/AN containing up to 25% of water. Depending on the water content, the TATP/AN mixtures possess higher detonability values than the ANFO explosives. A semi-logarithmic relationship between the D values and oxygen coefficients has been derived for all the mixtures studied at the charge density of 1000 kg m -3 . Among the mixtures studied, this relationship distinguishes several samples of the type of 'tertiary explosives' as well as samples that approach 'high explosives' in their performances and detonation velocities

  11. Complex mixtures: Hazard identification and risk assessment

    NARCIS (Netherlands)

    Fay, R.M.; Feron, V.J.

    1996-01-01

    Regarding risk evaluation of complex mixtures, the Working Group discussed the following topics: evaluation of the mixture as a whole, fractionation of the mixture, identification of the 'top ten' chemicals, and composite standards. It was concluded that no standard methodology for hazard

  12. Nonparametric Mixture of Regression Models.

    Science.gov (United States)

    Huang, Mian; Li, Runze; Wang, Shaoli

    2013-07-01

    Motivated by an analysis of US house price index data, we propose nonparametric finite mixture of regression models. We study the identifiability issue of the proposed models, and develop an estimation procedure by employing kernel regression. We further systematically study the sampling properties of the proposed estimators, and establish their asymptotic normality. A modified EM algorithm is proposed to carry out the estimation procedure. We show that our algorithm preserves the ascent property of the EM algorithm in an asymptotic sense. Monte Carlo simulations are conducted to examine the finite sample performance of the proposed estimation procedure. An empirical analysis of the US house price index data is illustrated for the proposed methodology.

  13. TRANSPORT PROPERTIES FOR REFRIGERANT MIXTURES

    Directory of Open Access Journals (Sweden)

    V. Geller

    2014-06-01

    Full Text Available A set of models to predict viscosity and thermal conductivity of refrigerant mixtures is developed. A general model for viscosity and thermal conductivity use the three contributions sum form (the dilute-gas terms, the residual terms, and the liquid terms. The corresponding states model is recommended to predict the dense gas transport properties over a range of reduced density from 0 to 2. It is shown that the RHS model provides the most reliable results for the saturated-liquid and the compressed-liquid transport properties over a range of given temperatures from 0,5 to 0,95.

  14. Apatite-Melt Partitioning at 1 Bar: An Assessment of Apatite-Melt Exchange Equilibria Resulting from Non-Ideal Mixing of F and Cl in Apatite

    Science.gov (United States)

    McCubbin, F. M.; Ustunisik, G.; Vander Kaaden, K. E.

    2016-01-01

    The mineral apatite [Ca5(PO4)3(F,Cl,OH)] is present in a wide range of planetary materials. Due to the presence of volatiles within its crystal structure (X-site), many recent studies have attempted to use apatite to constrain the volatile contents of planetary magmas and mantle sources. In order to use the volatile contents of apatite to precisely determine the abundances of volatiles in coexisting silicate melt or fluids, thermodynamic models for the apatite solid solution and for the apatite components in multi-component silicate melts and fluids are required. Although some thermodynamic models for apatite have been developed, they are incomplete. Furthermore, no mixing model is available for all of the apatite components in silicate melts or fluids, especially for F and Cl components. Several experimental studies have investigated the apatite-melt and apatite-fluid partitioning behavior of F, Cl, and OH in terrestrial and planetary systems, which have determined that apatite-melt partitioning of volatiles are best described as exchange equilibria similar to Fe-Mg partitioning between olivine and silicate melt. However, McCubbin et al. recently reported that the exchange coefficients may vary in portions of apatite compositional space where F, Cl, and OH do not mix ideally in apatite. In particular, solution calorimetry data of apatite compositions along the F-Cl join exhibit substantial excess enthalpies of mixing. In the present study, we conducted apatite-melt partitioning experiments in evacuated, sealed silica-glass tubes at approximately 1 bar and 950-1050 degrees Centigrade on a synthetic Martian basalt composition equivalent to the basaltic shergottite Queen Alexandria Range (QUE) 94201. These experiments were conducted dry, at low pressure, to assess the effects of temperature and apatite composition on the partitioning behavior of F and Cl between apatite and basaltic melt along the F-Cl apatite binary join, where there is non-ideal mixing of F and Cl

  15. Supercritical Water Mixture (SCWM) Experiment

    Science.gov (United States)

    Hicks, Michael C.; Hegde, Uday G.

    2012-01-01

    The subject presentation, entitled, Supercritical Water Mixture (SCWM) Experiment, was presented at the International Space Station (ISS) Increment 33/34 Science Symposium. This presentation provides an overview of an international collaboration between NASA and CNES to study the behavior of a dilute aqueous solution of Na2SO4 (5% w) at near-critical conditions. The Supercritical Water Mixture (SCWM) investigation, serves as important precursor work for subsequent Supercritical Water Oxidation (SCWO) experiments. The SCWM investigation will be performed in DECLICs High Temperature Insert (HTI) for the purpose of studying critical fluid phenomena at high temperatures and pressures. The HTI includes a completely sealed and integrated test cell (i.e., Sample Cell Unit SCU) that will contain approximately 0.3 ml of the aqueous test solution. During the sequence of tests, scheduled to be performed in FY13, temperatures and pressures will be elevated to critical conditions (i.e., Tc = 374C and Pc = 22 MPa) in order to observe salt precipitation, precipitate agglomeration and precipitate transport in the presence of a temperature gradient without the influences of gravitational forces. This presentation provides an overview of the motivation for this work, a description of the DECLIC HTI hardware, the proposed test sequences, and a brief discussion of the scientific research objectives.

  16. Exploring the Fate of Nitrogen Heterocycles in Complex Prebiotic Mixtures

    Science.gov (United States)

    Smith, Karen E.; Callahan, Michael P.; Cleaves, Henderson J.; Dworkin, Jason P.; House, Christopher H.

    2011-01-01

    A long standing question in the field of prebiotic chemistry is the origin of the genetic macromolecules DNA and RNA. DNA and RNA have very complex structures with repeating subunits of nucleotides, which are composed of nucleobases (nitrogen heterocycles) connected to sugar-phosphate. Due to the instability of some nucleobases (e.g. cytosine), difficulty of synthesis and instability of D-ribose, and the likely scarcity of polyphosphates necessary for the modern nucleotides, alternative nucleotides have been proposed for constructing the first genetic material. Thus, we have begun to investigate the chemistry of nitrogen heterocycles in plausible, complex prebiotic mixtures in an effort to identify robust reactions and potential alternative nucleotides. We have taken a complex prebiotic mixture produced by a spark discharge acting on a gas mixture of N2, CO2, CH4, and H2, and reacted it with four nitrogen heterocycles: uracil, 5-hydroxymethyluracil, guanine, and isoxanthopterin (2-amino-4,7-dihydroxypteridine). The products of the reaction between the spark mixture and each nitrogen heterocycle were characterized by liquid chromatography coupled to UV spectroscopy and Orbitrap mass spectrometry. We found that the reaction between the spark mixtUl'e and isoxanthopterin formed one major product, which was a cyanide adduct. 5-hydroxymethyluracil also reacted with the spark mixture to form a cyanide adduct, uracil-5-acetonitrile, which has been synthesized previously by reacting HCN with S-hydroxymethyluracil. Unlike isoxanthopterin, the chromatogram of the 5-hydroxymethyluracil reaction was much more complex with multiple products including spark-modified dimers. Additionally, we observed that HMU readily self-polymerizes in solution to a variety of oligomers consistent with those suggested by Cleaves. Guanine and uracil, the biological nucleobases, did not react with the spark mixture, even at high temperature (100 C). This suggests that there are alternative

  17. Perceptual blending in odor mixtures depends on the nature of odorants and human olfactory expertise.

    Science.gov (United States)

    Barkat, S; Le Berre, E; Coureaud, G; Sicard, G; Thomas-Danguin, T

    2012-02-01

    Our olfactory system is confronted with complex mixtures of odorants, often recognized as single entities due to odor blending (e.g., coffee). In contrast, we are also able to discriminate odors from complex mixtures (e.g., off-odors). Therefore, the olfactory system is able to engage either configural or elemental processes when confronted with mixtures. However, the rules that govern the involvement of these processes during odor perception remain poorly understood. In our first experiment, we examined whether simple odorant mixtures (binary/ternary) could elicit configural perception. Twenty untrained subjects were asked to evaluate the odor typicality of mixtures and their constituents. The results revealed a significant increase in odor typicality in some but not all mixtures as compared with the single components, which suggest that perceptual odor blending can occur only in specific mixtures (configural processing). In our second experiment, we tested the hypothesis that general olfactory expertise can improve elemental perception of mixtures. Thirty-two trained subjects evaluated the odor typicality of the stimuli presented during the first experiment, and their responses were compared with those obtained from the untrained panelists. The results support the idea that general training with odors increases the elemental perception of binary and ternary blending mixtures.

  18. Mixtures Research at NIEHS: An Evolving Program

    Science.gov (United States)

    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

  19. Non-ideality of methanol solution's of artificial serum in the mole fraction range from 5 x 10(-4) to 5 x 10(-3) at 25 degrees C

    DEFF Research Database (Denmark)

    Ralloff, K.P.G.; Westh, Peter; Purssell, R.A.

    2003-01-01

    Vapour pressure and excess partial molar enthalpy were measured at 25 degreesC for solutions of methanol in H2O and artificial serum solutions. The mole fraction range studied was from 5 x 10(-4) to 5 x 10(-3). From the vapour pressure data, the partial pressures were determined by the Barker......), on the other hand, produced the osmotic coefficient significantly larger than unity in serum solutions studied. This is consistent with the findings by the earlier freezing point depression study on ethanol in human blood serum solutions. The partial molar enthalpy data indicated highly non-ideal behaviours...

  20. A novel method dependent only on the mixture information (MIM) for evaluating the toxicity of mixture

    International Nuclear Information System (INIS)

    Zhang Jin; Liu Shushen; Liu Hailing; Zhu Xiangwei; Mi Xiaojuan

    2011-01-01

    Compound contamination and toxicity interaction necessitate the development of models that have an insight into the combined toxicity of chemicals. In this paper, a novel and simple model dependent only on the mixture information (MIM), was developed. Firstly, the concentration-response data of seven groups of binary and multi-component (pseudo-binary) mixtures with different mixture ratios to Vibrio qinghaiensis sp.-Q67 were determined using the microplate toxicity analysis. Then, a desirable non-linear function was selected to fit the data. It was found that there are good linear correlations between the location parameter (α) and mixture ratio (p) of a component and between the steepness (β) and p. Based on the correlations, a mixture toxicity model independent of pure component toxicity profiles was built. The model can be used to accurately estimate the toxicities of the seven groups of mixtures, which greatly simplified the predictive procedure of the combined toxicity. - Highlights: → We develop a mixture toxicity model only on the mixture toxicity profiles. → We regard all multi-component mixtures as pseudo-binary mixtures. → The model is built by using a set of uniform design mixtures. → The model is validated by using a set of fixed concentration ratio mixtures. → The model can also predict the toxicity of external mixtures. - A novel method depends only on mixture information but not on pure component toxicity profiles for evaluating the combined toxicity.

  1. Use of waste plastic in concrete mixture as aggregate replacement.

    Science.gov (United States)

    Ismail, Zainab Z; Al-Hashmi, Enas A

    2008-11-01

    Industrial activities in Iraq are associated with significant amounts of non-biodegradable solid waste, waste plastic being among the most prominent. This study involved 86 experiments and 254 tests to determine the efficiency of reusing waste plastic in the production of concrete. Thirty kilograms of waste plastic of fabriform shapes was used as a partial replacement for sand by 0%, 10%, 15%, and 20% with 800 kg of concrete mixtures. All of the concrete mixtures were tested at room temperature. These tests include performing slump, fresh density, dry density, compressive strength, flexural strength, and toughness indices. Seventy cubes were molded for compressive strength and dry density tests, and 54 prisms were cast for flexural strength and toughness indices tests. Curing ages of 3, 7, 14, and 28 days for the concrete mixtures were applied in this work. The results proved the arrest of the propagation of micro cracks by introducing waste plastic of fabriform shapes to concrete mixtures. This study insures that reusing waste plastic as a sand-substitution aggregate in concrete gives a good approach to reduce the cost of materials and solve some of the solid waste problems posed by plastics.

  2. Model structure selection in convolutive mixtures

    DEFF Research Database (Denmark)

    Dyrholm, Mads; Makeig, Scott; Hansen, Lars Kai

    2006-01-01

    The CICAAR algorithm (convolutive independent component analysis with an auto-regressive inverse model) allows separation of white (i.i.d) source signals from convolutive mixtures. We introduce a source color model as a simple extension to the CICAAR which allows for a more parsimoneous...... representation in many practical mixtures. The new filter-CICAAR allows Bayesian model selection and can help answer questions like: 'Are we actually dealing with a convolutive mixture?'. We try to answer this question for EEG data....

  3. Some properties of explosive mixtures containing peroxides

    Energy Technology Data Exchange (ETDEWEB)

    Zeman, Svatopluk [Institute of Energetic Materials, Faculty of Chemical Technology, University of Pardubice, CZ-532 10 Pardubice (Czech Republic)], E-mail: svatopluk.zeman@upce.cz; Trzcinski, Waldemar A. [Institute of Chemistry, Military University of Technology, PL-00-908 Warsaw 49 (Poland); Matyas, Robert [Institute of Energetic Materials, Faculty of Chemical Technology, University of Pardubice, CZ-532 10 Pardubice (Czech Republic)

    2008-06-15

    This study concerns mixtures of triacetone triperoxide (3,3,6,6,9,9-hexamethyl-1,2,4,5,7,8-hexoxonane, TATP) and ammonium nitrate (AN) with added water (W), as the case may be, and dry mixtures of TATP with urea nitrate (UN). Relative performances (RP) of the mixtures and their individual components, relative to TNT, were determined by means of ballistic mortar. The detonation energies, E{sub 0}, and detonation velocities, D, were calculated for the mixtures studied by means of the thermodynamic code CHEETAH. Relationships have been found and are discussed between the RP and the E{sub 0} values related to unit volume of gaseous products of detonation of these mixtures. These relationships together with those between RP and oxygen balance values of the mixtures studied indicate different types of participation of AN and UN in the explosive decomposition of the respective mixtures. Dry TATP/UN mixtures exhibit lower RP than analogous mixtures TATP/AN containing up to 25% of water. Depending on the water content, the TATP/AN mixtures possess higher detonability values than the ANFO explosives. A semi-logarithmic relationship between the D values and oxygen coefficients has been derived for all the mixtures studied at the charge density of 1000 kg m{sup -3}. Among the mixtures studied, this relationship distinguishes several samples of the type of 'tertiary explosives' as well as samples that approach 'high explosives' in their performances and detonation velocities.

  4. Real surface (non-ideal) effects on nuclear explosion airblast from priscilla-type events, part 1: Comparison and evaluation of ideal and non-ideal airblast from priscilla computations; and part 2: Sharc hydrocode calculations of the priscilla event (phase 1). Final report, 12 March 1992-30 May 1995

    Energy Technology Data Exchange (ETDEWEB)

    Ethridge, N.H.; Keefer, J.H.; Crepeau, J.E.; Ekler, R.G.; Kennedy, L.W.

    1995-10-01

    An extensive analysis of the 24 June 1957 PRISCILLA 36.6 KT nuclear event at a 700 ft height of burst over a desert surface at the Nevada Test Site is presented, along with early time results from three hydrocode computations simulating that event. The computations included simulations of ideal, actual desert, and grassland surface. The desert computation produced reasonable agreement with most of the data from PRISCILiA. However, the precursor was not as advanced as that observed. The grassland computation produced a strong and persistent precursor. There was a mismatch between arrival times used for developing the thermal layers and those actually computed, indicating the need for coupling of the SHARC hydrocode and the THRML thermal layer codes. Both desert and grassland cases produced enhanced dynamic pressure impulses that attained a maximum of a factor of 8 above ideal in the range of concern to Army equipment Overturning computations for comhat vehicles showed ranges for overturning were extended by factors as large as 1.8 over ideal ground ranges. These effects have implications for Army tactics and doctrine and show the need for continuing non-ideal computations for other surfaces, yields, and heights of burst. Recommendations for further studies are included.

  5. Shear viscosity of liquid mixtures Mass dependence

    CERN Document Server

    Kaushal, R

    2002-01-01

    Expressions for zeroth, second, and fourth sum rules of transverse stress autocorrelation function of two component fluid have been derived. These sum rules and Mori's memory function formalism have been used to study shear viscosity of Ar-Kr and isotopic mixtures. It has been found that theoretical result is in good agreement with the computer simulation result for the Ar-Kr mixture. The mass dependence of shear viscosity for different mole fraction shows that deviation from ideal linear model comes even from mass difference in two species of fluid mixture. At higher mass ratio shear viscosity of mixture is not explained by any of the emperical model.

  6. Thermodynamic modeling of non-ideal mineral-fluid equilibria in the system Si-Al-Fe-Mg-Ca-Na-K-H-O-Cl at elevated temperatures and pressures: Implications for hydrothermal mass transfer in granitic rocks

    Science.gov (United States)

    Dolejš, David; Wagner, Thomas

    2008-01-01

    We present the results of thermodynamic modeling of fluid-rock interaction in the system Si-Al-Fe-Mg-Ca-Na-H-O-Cl using the GEM-Selektor Gibbs free energy minimization code. Combination of non-ideal mixing properties in solids with multicomponent aqueous fluids represents a substantial improvement and it provides increased accuracy over existing modeling strategies. Application to the 10-component system allows us to link fluid composition and speciation with whole-rock mineralogy, mass and volume changes. We have simulated granite-fluid interaction over a wide range of conditions (200-600 °C, 100 MPa, 0-5 m Cl and fluid/rock ratios of 10-2-104) in order to explore composition of magmatic fluids of variable salinity, temperature effects on fluid composition and speciation and to simulate several paths of alteration zoning. At low fluid/rock ratios (f/r) the fluid composition is buffered by the silicate-oxide assemblage and remains close to invariant. This behavior extends to a f/r of 0.1 which exceeds the amount of exsolved magmatic fluids controlled by water solubility in silicate melts. With increasing peraluminosity of the parental granite, the Na-, K- and Fe-bearing fluids become more acidic and the oxidation state increases as a consequence of hydrogen and ferrous iron transfer to the fluid. With decreasing temperature, saline fluids become more Ca- and Na-rich, change from weakly acidic to alkaline, and become significantly more oxidizing. Large variations in Ca/Fe and Ca/Mg ratios in the fluid are a potential geothermometer. The mineral assemblage changes from cordierite-biotite granites through two-mica granites to chlorite-, epidote- and zeolite-bearing rocks. We have carried out three rock-titration simulations: (1) reaction with the 2 m NaCl fluid leads to albitization, chloritization and desilication, reproducing essential features observed in episyenites, (2) infiltration of a high-temperature fluid into the granite at 400 °C leads to hydrolytic

  7. Simulation of mixture microstructures via particle packing models and their direct comparison with real mixtures

    Science.gov (United States)

    Gulliver, Eric A.

    The objective of this thesis to identify and develop techniques providing direct comparison between simulated and real packed particle mixture microstructures containing submicron-sized particles. This entailed devising techniques for simulating powder mixtures, producing real mixtures with known powder characteristics, sectioning real mixtures, interrogating mixture cross-sections, evaluating and quantifying the mixture interrogation process and for comparing interrogation results between mixtures. A drop and roll-type particle-packing model was used to generate simulations of random mixtures. The simulated mixtures were then evaluated to establish that they were not segregated and free from gross defects. A powder processing protocol was established to provide real mixtures for direct comparison and for use in evaluating the simulation. The powder processing protocol was designed to minimize differences between measured particle size distributions and the particle size distributions in the mixture. A sectioning technique was developed that was capable of producing distortion free cross-sections of fine scale particulate mixtures. Tessellation analysis was used to interrogate mixture cross sections and statistical quality control charts were used to evaluate different types of tessellation analysis and to establish the importance of differences between simulated and real mixtures. The particle-packing program generated crescent shaped pores below large particles but realistic looking mixture microstructures otherwise. Focused ion beam milling was the only technique capable of sectioning particle compacts in a manner suitable for stereological analysis. Johnson-Mehl and Voronoi tessellation of the same cross-sections produced tessellation tiles with different the-area populations. Control charts analysis showed Johnson-Mehl tessellation measurements are superior to Voronoi tessellation measurements for detecting variations in mixture microstructure, such as altered

  8. Thermodynamics of mixtures containing amines

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez, Juan Antonio [G.E.T.E.F. Dpto Termodinamica y Fisica Aplicada, Facultad de Ciencias, Universidad de Valladolid, Valladolid 47071 (Spain)], E-mail: jagl@termo.uva.es; Mozo, Ismael; Garcia de la Fuente, Isaias; Cobos, Jose Carlos [G.E.T.E.F. Dpto Termodinamica y Fisica Aplicada, Facultad de Ciencias, Universidad de Valladolid, Valladolid 47071 (Spain); Riesco, Nicolas [Department of Chemical Engineering, Loughborough University, Loughborough, LE113TU Leicestershire (United Kingdom)

    2008-01-30

    Mixtures with dimethyl or trimethylpyridines and alkane, aromatic compound or 1-alkanol have been examined using different theories: DISQUAC, Flory, the concentration-concentration structure factor, S{sub CC}(0), or the Kirkwood-Buff formalism. DISQUAC represents fairly well the available experimental data, and improves theoretical calculations from Dortmund UNIFAC. Two important effects have been investigated: (i) the effect of increasing the number of methyl groups attached to the aromatic ring of the amine; (ii) the effect of modifying the position of the methyl groups in this ring. The molar excess enthalpy, H{sup E}, and the molar excess volume, V{sup E}, decrease in systems with alkane or methanol as follows: pyridine > 3-methylpyridine > 3,5-dimethylpyridine and pyridine > 2-methylpyridine > 2,4-dimethylpyridine > 2,4,6-trimethylpyridine, which has been attributed to a weakening of the amine-amine interactions in the same sequences. This is in agreement with the relative variation of the effective dipole moment, {mu}-bar, and of the differences between the boiling temperature of a pyridine base and that of the homomorphic alkane. For heptane solutions, the observed H{sup E} variation, H{sup E} (3,5-dimethylpyridine) > H{sup E} (2,4-dimethylpyridine) > H{sup E} (2,6-dimethylpyridine), is explained similarly. Calculations on the basis of the Flory model confirm that orientational effects become weaker in systems with alkane in the order: pyridine > methylpyridine > dimethylpyridine > trimethylpyridine. S{sub CC}(0) calculations show that steric effects increase with the number of CH{sub 3}- groups in the pyridine base, and that the steric effects exerted by methyl groups in positions 2 and 6 are higher than when they are placed in positions 3 and 5. The hydrogen bond energy in methanol mixtures is independent of the pyridine base, and it is estimated to be -35.2 kJ mol{sup -1}. Heterocoordination in these solutions is due in part to size effects. Their

  9. Hydrodynamic 'memory' of binary fluid mixtures

    International Nuclear Information System (INIS)

    Kalashnik, M. V.; Ingel, L. Kh.

    2006-01-01

    A theoretical analysis is presented of hydrostatic adjustment in a two-component fluid system, such as seawater stratified with respect to temperature and salinity. Both linear approximation and nonlinear problem are investigated. It is shown that scenarios of relaxation to a hydrostatically balanced state in binary fluid mixtures may substantially differ from hydrostatic adjustment in fluids that can be stratified only with respect to temperature. In particular, inviscid two-component fluids have 'memory': a horizontally nonuniform disturbance in the initial temperature or salinity distribution does not vanish even at the final stage, transforming into a persistent thermohaline 'trace.' Despite stability of density stratification and convective stability of the fluid system by all known criteria, an initial temperature disturbance may not decay and may even increase in amplitude. Moreover, its sign may change (depending on the relative contributions of temperature and salinity to stable background density stratification). Hydrostatic adjustment may involve development of discontinuous distributions from smooth initial temperature or concentration distributions. These properties of two-component fluids explain, in particular, the occurrence of persistent horizontally or vertically nonuniform temperature and salinity distributions in the ocean, including discontinuous ones

  10. Optimizing laboratory mixture design as it relates to field compaction to improve asphalt mixture durability.

    Science.gov (United States)

    2015-11-01

    Most departments of transportation, including Indiana, currently use the Superpave mixture design method to design asphalt mixtures. : This method specifies that the optimum asphalt content for a given gradation be selected at 4 percent air voids. Du...

  11. STAR-POLYMER -- COLLOID MIXTURES

    Directory of Open Access Journals (Sweden)

    J.Dzubiella

    2002-01-01

    Full Text Available Recent results in theory and simulation of star-polymer--colloid mixtures are reviewed. We present the effective interaction between hard, colloidal particles and star polymers in a good solvent derived by monomer-resolved Molecular Dynamics simulations and theoretical arguments. The relevant parameters are the size ratio q between the stars and the colloids, as well as the number of polymeric arms f (functionality attached to the common center of the star. By covering a wide range of q's ranging from zero (star against a flat wall up to about 0.5, we establish analytical forms for the star-colloid interaction which are in excellent agreement with simulation results. By employing this cross interaction and the effective interactions between stars and colloids themselves, a demixing transition in the fluid phase is observed and systematically investigated for different arm numbers and size ratios. The demixing binodals are compared with experimental observations and found to be consistent. Furthermore, we map the full two-component system on an effective one-component description for the colloids, by inverting the two-component Ornstein-Zernike equations. Some recent results for the depletion interaction and freezing transitions are shown.

  12. Vapor pressures and activity coefficients of binary mixtures of 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide with acetonitrile and tetrahydrofuran

    International Nuclear Information System (INIS)

    Safarov, Javid; Geppert-Rybczyńska, Monika; Hassel, Egon; Heintz, Andreas

    2012-01-01

    Highlights: ► A new apparatus for the determination of VLE is presented. ► The first vapor pressures for binary mixtures containing aprotic solvents in IL are reported. ► Calculated activity coefficients and osmotic coefficients reveal a strong non-ideal behavior. ► A more detailed study of the highly diluted IL concentration range is necessary to test the Debye–Hückel law. - Abstract: A new apparatus for the determination of VLE has been constructed which works for absolute pressure measurements as well as for measuring differential pressures. The first results obtained are (vapor + liquid) equilibria (VLE) of binary mixtures containing acetonitrile or tetrahydrofuran and the ionic liquid (IL) 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide [EMIm][NTf2] by using the absolute pressures method. VLE measurements were carried out over the whole concentration range at four different temperatures between 293.15 K and 313.15 K. Activity coefficients (γ 1 ) of the solvents in [EMIm][NTf2] and their osmotic coefficients (φ 1 ) have been determined from the VLE data.

  13. Modeling the phase equilibria of a H2O-CO2 mixture with PC-SAFT and tPC-PSAFT equations of state

    Science.gov (United States)

    Diamantonis, Nikolaos I.; Economou, Ioannis G.

    2012-06-01

    Water-carbon dioxide binary mixtures are important for a number of industrial and environmental applications. Accurate modeling of the thermodynamic properties is a challenging task due to the highly non-ideal intermolecular interactions. In this work, two models based on the Statistical Associating Fluid Theory (SAFT) are used to correlate reliable experimental vapor-liquid equilibria (VLE) and liquid-liquid equilibria (LLE) data in the temperature range 298-533 K. CO2 is modeled as a non-associating or associating component within the Perturbed Chain-SAFT (PC-SAFT) and as a quadrupolar component within the truncated PC-Polar SAFT (tPC-PSAFT). It is shown that PC-SAFT with explicit account of H2O-CO2 cross-association and tPC-PSAFT with explicit account of CO2 quadrupolar interactions are the most accurate of the models examined. Saturated liquid mixture density data are accurately predicted by the two models.

  14. Least median of squares and iteratively re-weighted least squares as robust linear regression methods for fluorimetric determination of α-lipoic acid in capsules in ideal and non-ideal cases of linearity.

    Science.gov (United States)

    Korany, Mohamed A; Gazy, Azza A; Khamis, Essam F; Ragab, Marwa A A; Kamal, Miranda F

    2018-03-26

    This study outlines two robust regression approaches, namely least median of squares (LMS) and iteratively re-weighted least squares (IRLS) to investigate their application in instrument analysis of nutraceuticals (that is, fluorescence quenching of merbromin reagent upon lipoic acid addition). These robust regression methods were used to calculate calibration data from the fluorescence quenching reaction (∆F and F-ratio) under ideal or non-ideal linearity conditions. For each condition, data were treated using three regression fittings: Ordinary Least Squares (OLS), LMS and IRLS. Assessment of linearity, limits of detection (LOD) and quantitation (LOQ), accuracy and precision were carefully studied for each condition. LMS and IRLS regression line fittings showed significant improvement in correlation coefficients and all regression parameters for both methods and both conditions. In the ideal linearity condition, the intercept and slope changed insignificantly, but a dramatic change was observed for the non-ideal condition and linearity intercept. Under both linearity conditions, LOD and LOQ values after the robust regression line fitting of data were lower than those obtained before data treatment. The results obtained after statistical treatment indicated that the linearity ranges for drug determination could be expanded to lower limits of quantitation by enhancing the regression equation parameters after data treatment. Analysis results for lipoic acid in capsules, using both fluorimetric methods, treated by parametric OLS and after treatment by robust LMS and IRLS were compared for both linearity conditions. Copyright © 2018 John Wiley & Sons, Ltd.

  15. Catalytic Gasification of Coal using Eutectic Salt Mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Atul Sheth; Pradeep Agrawal; Yaw D. Yeboah

    1998-12-04

    The objectives of this study are to: identify appropriate eutectic salt mixture catalysts for coal gasification; assess agglomeration tendency of catalyzed coal; evaluate various catalyst impregnation techniques to improve initial catalyst dispersion; evaluate effects of major process variables (such as temperature, system pressure, etc.) on coal gasification; evaluate the recovery, regeneration and recycle of the spent catalysts; and conduct an analysis and modeling of the gasification process to provide better understanding of the fundamental mechanisms and kinetics of the process. A review of the collected literature was carried out. The catalysts which have been used for gasification can be roughly classified under the following five groups: alkali metal salts; alkaline earth metal oxides and salts; mineral substances or ash in coal; transition metals and their oxides and salts; and eutectic salt mixtures. Studies involving the use of gasification catalysts have been conducted. However, most of the studies focused on the application of individual catalysts. Only two publications have reported the study of gasification of coal char in CO2 and steam catalyzed by eutectic salt mixture catalysts. By using the eutectic mixtures of salts that show good activity as individual compounds, the gasification temperature can be reduced possibly with still better activity and gasification rates due to improved dispersion of the molten catalyst on the coal particles. For similar metal/carbon atomic ratios, eutectic catalysts were found to be consistently more active than their respective single salts. But the exact roles that the eutectic salt mixtures play in these are not well understood and details of the mechanisms remain unclear. The effects of the surface property of coals and the application methods of eutectic salt mixture catalysts with coal chars on the reactivity of gasification will be studied. Based on our preliminary evaluation of the literature, a ternary

  16. Assessment of mixture toxicity of copper, cadmium, and phenanthrenequinone to the marine bacterium Vibrio fischeri.

    Science.gov (United States)

    Wang, Wenxi; Lampi, Mark A; Huang, Xiao-Dong; Gerhardt, Karen; Dixon, D George; Greenberg, Bruce M

    2009-04-01

    Transition metals and polycyclic aromatic hydrocarbons (PAHs) are cocontaminants at many sites. Contaminants in mixtures are known to interact with biological systems in ways that can greatly alter the toxicity of individual compounds. The toxicities (individually and as mixtures) of copper (Cu), a redox-active metal; cadmium (Cd), a nonredox active metal; and phenanthrenequinone (PHQ), a redox-active oxygenated PAH, were examined using the bioluminescent bacterium Vibrio fischeri. We found that the cotoxicity of Cu/PHQ was dependent on the ratio of concentrations of each chemical in the mixture. Different interaction types (synergism, antagonism, and additivity) were observed with different combinations of these toxicants. The interaction types changed from antagonism at a low Cu to PHQ ratio (1:4), to additive at an intermediate Cu to PHQ ratio (2:3), to synergistic at higher Cu to PHQ ratios (3:2 and 4:1). In contrast to Cu/PHQ mixtures, the cotoxicity of Cd/PHQ did not change at different mixture ratios and was found for the most part to be additive. For the individual chemicals and their mixtures, reactive oxygen species (ROS) production was observed in V. fischeri, suggesting that individual and mixture toxicity of Cu, Cd, and PHQ to V. fischeri involves ROS-related mechanisms. This study shows that mixture ratios can alter individual chemical toxicity, and should be taken into account in risk assessment. Copyright 2008 Wiley Periodicals, Inc.

  17. Fibril assembly in whey protein mixtures

    NARCIS (Netherlands)

    Bolder, S.G.

    2007-01-01

    The objective of this thesis was to study fibril assembly in mixtures of whey proteins. The effect of the composition of the protein mixture on the structures and the resulting phase behaviour was investigated. The current work has shown that beta-lactoglobulin is responsible for the fibril assembly

  18. Robust classification using mixtures of dependency networks

    DEFF Research Database (Denmark)

    Gámez, José A.; Mateo, Juan L.; Nielsen, Thomas Dyhre

    2008-01-01

    -ups are often obtained at the expense of accuracy. In this paper we try to address this issue through the use of mixtures of dependency networks. To reduce learning time and improve robustness when dealing with data sparse classes, we outline methods for reusing calculations across mixture components. Finally...

  19. Mixture Modeling: Applications in Educational Psychology

    Science.gov (United States)

    Harring, Jeffrey R.; Hodis, Flaviu A.

    2016-01-01

    Model-based clustering methods, commonly referred to as finite mixture modeling, have been applied to a wide variety of cross-sectional and longitudinal data to account for heterogeneity in population characteristics. In this article, we elucidate 2 such approaches: growth mixture modeling and latent profile analysis. Both techniques are…

  20. Buffer gas cooling and mixture analysis

    Science.gov (United States)

    Patterson, David S.; Doyle, John M.

    2018-03-06

    An apparatus for spectroscopy of a gas mixture is described. Such an apparatus includes a gas mixing system configured to mix a hot analyte gas that includes at least one analyte species in a gas phase into a cold buffer gas, thereby forming a supersaturated mixture to be provided for spectroscopic analysis.

  1. Two-microphone Separation of Speech Mixtures

    DEFF Research Database (Denmark)

    2006-01-01

    Matlab source code for underdetermined separation of instaneous speech mixtures. The algorithm is described in [1] Michael Syskind Pedersen, DeLiang Wang, Jan Larsen and Ulrik Kjems: ''Two-microphone Separation of Speech Mixtures,'' 2006, submitted for journal publoication. See also, [2] Michael...

  2. The Modified Enskog Equation for Mixtures

    NARCIS (Netherlands)

    Beijeren, H. van; Ernst, M.H.

    1973-01-01

    In a previous paper it was shown that a modified form of the Enskog equation, applied to mixtures of hard spheres, should be considered as the correct extension of the usual Enskog equation to the case of mixtures. The main argument was that the modified Enskog equation leads to linear transport

  3. Spectrometric mixture analysis: An unexpected wrinkle

    Indian Academy of Sciences (India)

    Administrator

    Dedicated to the memory of the late Professor S K Rangarajan. Spectrometric mixture analysis: An unexpected wrinkle. †. ROBERT DE LEVIE. Chemistry Department ..... For a quick visual check of the mixture spectra, we plotted the absorbances of those solutions that have a constant value of c + t, such as (0, 180), (90,.

  4. Separation of gas mixtures by centrifugation

    Science.gov (United States)

    Park, C.; Love, W. L.

    1972-01-01

    Magnetohydrodynamic (MHD) centrifuge utilizing electric currents and magnetic fields produces a magnetic force which develops supersonic rotational velocities in gas mixtures. Device is superior to ordinary centrifuges because rotation of gas mixture is produced by MHD force rather than mechanical means.

  5. Intelligent gas-mixture flow sensor

    NARCIS (Netherlands)

    Lammerink, Theodorus S.J.; Dijkstra, Fred; Houkes, Z.; van Kuijk, J.C.C.; van Kuijk, Joost

    A simple way to realize a gas-mixture flow sensor is presented. The sensor is capable of measuring two parameters from a gas flow. Both the flow rate and the helium content of a helium-nitrogen gas mixture are measured. The sensor exploits two measurement principles in combination with (local)

  6. Thermodynamics of organic mixtures containing amines. VIII. Systems with quinoline

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez, Juan Antonio [G.E.T.E.F., Grupo Especializado en Termodinamica de Equilibrio entre Fases, Departamento de Fisica Aplicada, Facultad de Ciencias, Universidad de Valladolid, E-47071 Valladolid (Spain)], E-mail: jagl@termo.uva.es; Domanska, Urszula; Zawadzki, Maciej [Physical Chemistry Division, Faculty of Chemistry, Warsaw University of Technology, 00-664 Warsaw (Poland)

    2008-08-15

    (Solid + liquid) equilibrium temperatures for mixtures containing quinoline and 1-dodecanol, 1-hexadecanol, or 1-octadecanol have been measured using a dynamic method. (Quinoline + benzene, +alkane, or +1-alkanol) systems were investigated using DISQUAC. The corresponding interaction parameters are reported. The model yields a good representation of molar excess Gibbs free energies, G{sup E}, molar excess enthalpies, H{sup E}, and of the (solid + liquid) equilibria, SLE. Interactional and structural effects were analysed comparing H{sup E} and the molar excess internal energy at constant volume, U{sub V}{sup E}. It was encountered that structural effects are very important in systems involving alkanes or 1-alkanols. Interactions between amine molecules are stronger in mixtures with quinoline than in those containing pyridine, which was ascribed to the higher polarizability of quinoline.

  7. Who and What Does Involvement Involve?

    DEFF Research Database (Denmark)

    Hansen, Jeppe Oute; Petersen, A.; Huniche, L.

    2015-01-01

    , and on what grounds, involvement of relatives is perceived in Danish psychiatry. Paradoxically, the current understanding of involvement of relatives fails to take into consideration the perspectives of the relatives per se and families that were being studied. By analyzing involvement from a discourse...... the responsibility toward the mental health of the ill individual as well as toward the psychological milieu of the family....

  8. Supercritical separation process for complex organic mixtures

    Science.gov (United States)

    Chum, H.L.; Filardo, G.

    1990-10-23

    A process is disclosed for separating low molecular weight components from complex aqueous organic mixtures. The process includes preparing a separation solution of supercritical carbon dioxide with an effective amount of an entrainer to modify the solvation power of the supercritical carbon dioxide and extract preselected low molecular weight components. The separation solution is maintained at a temperature of at least about 70 C and a pressure of at least about 1,500 psi. The separation solution is then contacted with the organic mixtures while maintaining the temperature and pressure as above until the mixtures and solution reach equilibrium to extract the preselected low molecular weight components from the organic mixtures. Finally, the entrainer/extracted components portion of the equilibrium mixture is isolated from the separation solution. 1 fig.

  9. Deformation Properties and Fatigue of Bituminous Mixtures

    Directory of Open Access Journals (Sweden)

    Frantisek Schlosser

    2013-01-01

    Full Text Available Deformation properties and fatigue performance are important characteristics of asphalt bound materials which are used for construction of pavement layers. Viscoelastic asphalt mixtures are better characterized via dynamic tests. This type of tests allows us to collate materials with regard to axle vibrations which lie usually in the range of 6 Hz–25 Hz for standard conditions. Asphalt modified for heat sensitivity in the range from −20°C to +60°C has significant impact on the overall characteristics of the mixture. Deformation properties are used as inputs for empirical mixture design, and fatigue performance of asphalt mixtures reflects the parameters of functional tests. Master curves convey properties of asphalt mixtures for various conditions and allow us to evaluate them without the need of time expensive testing.

  10. Radiolytic decomposition of water-ethanol mixtures

    International Nuclear Information System (INIS)

    Baquey, Charles

    1968-07-01

    This research thesis addresses the study of the behaviour of binary mixtures submitted to ionizing radiations, and notably aims, by studying the case of water-ethanol mixtures, at verifying solutions proposed by previously published works on the origin of hydrogen atoms and of molecular hydrogen, on the intervention of excited atoms, and on the origin of products appearing under radiolysis. The experimental part of this work consists in the dosing of products formed in water-ethanol mixtures irradiated in presence or absence of nitrate, hydrogen, hydrocarbon, acetaldehyde, 2-3 butanediol and nitrite. Results are discussed and interpreted in terms of acetaldehyde efficiency, 2-3 butanediol efficiencies, and hydrocarbon efficiencies in pure ethanol, and in water-ethanol mixtures. The influence of the presence of nitrate ions in mixtures is also discussed

  11. New theoretical framework for designing nonionic surfactant mixtures that exhibit a desired adsorption kinetics behavior.

    Science.gov (United States)

    Moorkanikkara, Srinivas Nageswaran; Blankschtein, Daniel

    2010-12-21

    How does one design a surfactant mixture using a set of available surfactants such that it exhibits a desired adsorption kinetics behavior? The traditional approach used to address this design problem involves conducting trial-and-error experiments with specific surfactant mixtures. This approach is typically time-consuming and resource-intensive and becomes increasingly challenging when the number of surfactants that can be mixed increases. In this article, we propose a new theoretical framework to identify a surfactant mixture that most closely meets a desired adsorption kinetics behavior. Specifically, the new theoretical framework involves (a) formulating the surfactant mixture design problem as an optimization problem using an adsorption kinetics model and (b) solving the optimization problem using a commercial optimization package. The proposed framework aims to identify the surfactant mixture that most closely satisfies the desired adsorption kinetics behavior subject to the predictive capabilities of the chosen adsorption kinetics model. Experiments can then be conducted at the identified surfactant mixture condition to validate the predictions. We demonstrate the reliability and effectiveness of the proposed theoretical framework through a realistic case study by identifying a nonionic surfactant mixture consisting of up to four alkyl poly(ethylene oxide) surfactants (C(10)E(4), C(12)E(5), C(12)E(6), and C(10)E(8)) such that it most closely exhibits a desired dynamic surface tension (DST) profile. Specifically, we use the Mulqueen-Stebe-Blankschtein (MSB) adsorption kinetics model (Mulqueen, M.; Stebe, K. J.; Blankschtein, D. Langmuir 2001, 17, 5196-5207) to formulate the optimization problem as well as the SNOPT commercial optimization solver to identify a surfactant mixture consisting of these four surfactants that most closely exhibits the desired DST profile. Finally, we compare the experimental DST profile measured at the surfactant mixture condition

  12. Microheterogeneity in binary mixtures of water with CH3OH and CD3OH: ATR-IR spectroscopic, chemometric and DFT studies.

    Science.gov (United States)

    Tomza, Paweł; Wrzeszcz, Władysław; Mazurek, Sylwester; Szostak, Roman; Czarnecki, Mirosław Antoni

    2018-01-30

    Here we report ATR-IR spectroscopic study on the separation at a molecular level (microheterogeneity) and the degree of deviation of H 2 O/CH 3 OH and H 2 O/CD 3 OH mixtures from the ideal mixture. Of particular interest is the effect of isotopic substitution in methyl group on molecular structure and interactions in both mixtures. To obtain comprehensive information from the multivariate data we applied the excess molar absorptivity spectra together with two-dimensional correlation analysis (2DCOS) and chemometric methods. In addition, the experimental results were compared and discussed with the structures of various model clusters obtained from theoretical (DFT) calculations. Our results evidence the presence of separation at a molecular level and deviation from the ideal mixture for both mixtures. The experimental and theoretical results show that the maximum of these deviations appears at equimolar mixture. Both mixtures consist of three kinds of species: homoclusters of water and methanol and mixed clusters (heteroclusters). The heteroclusters exist in the whole range of mole fractions with the maximum close to the equimolar mixture. At this mixture composition near 55-60% of molecules are involved in heteroclusters. In contrast, the homoclusters of water occur in a limited range of mole fractions (X ME  mixture are involved in stronger hydrogen bonding than those in bulk water. All these results indicate that both mixtures have similar degree of deviation from the ideal mixture. Copyright © 2018 Elsevier B.V. All rights reserved.

  13. Non-equilibrium theory employing enthalpy-based equation of state for binary solid and porous mixtures

    Science.gov (United States)

    Nayak, B.; Menon, S. V. G.

    2018-03-01

    A generalized enthalpy-based equation of state, which includes thermal electron excitations and non-equilibrium thermal energies, is formulated for binary solid and porous mixtures. Our approach gives rise to an extra contribution to mixture volume, in addition to those corresponding to average mixture parameters. This excess term involves the difference of thermal enthalpies of the two components, which depend on their individual temperatures. We propose to use the Hugoniot of the components to compute non-equilibrium temperatures in the mixture. These are then compared with the average temperature obtained from the mixture Hugoniot, thereby giving an estimate of non-equilibrium effects. The Birch-Murnaghan model for the zero-temperature isotherm and a linear thermal model are then used for applying the method to several mixtures, including one porous case. Comparison with experimental data on the pressure-volume Hugoniot and shock speed versus particle speed shows good agreement.

  14. Coking technology using packed coal mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Kuznichenko, V.M.; Shteinberg, Eh.A.; Tolstoi, A.P. (Khar' kovskii Nauchno-Issledovatel' skii Uglekhimicheskii Institut, Kharkov (Ukrainian SSR))

    1991-08-01

    Discusses coking of packed coal charges in the FRG, USSR, France, India, Poland and Czechoslovakia. The following aspects are evaluated: types of weakly caking coals that are used as components of packed mixtures, energy consumption of packing, effects of coal mixture packing on coke oven design, number of coke ovens in a battery, heating temperature, coking time, coke properties, investment and operating cost. Statistical data that characterize the Saarberg packing process used in the FRG are analyzed. Packing coal mixtures for coking improves coke quality and reduces environmental pollution. 4 refs.

  15. APPARATUS FOR HANDLING MIXTURES OF SOLID MATERIALS

    Science.gov (United States)

    Hubbell, J.P.

    1959-08-25

    An apparatus is described for handling either a mixture of finely subdivided materials or a single material requiring a compacting action thereon preparatory to a chemical reducing process carried out in a crucible container. The apparatus is designed to deposit a mixture of dust-forming solid materials in a container while confining the materials against escape into the surrounding atmosphere. A movable filling tube, having a compacting member, is connected to the container and to a covered hopper receiving the mixture of materials. The filling tube is capable of reciprocating in the container and their relative positions are dependent upon the pressure established upon the material by the compacting member.

  16. Probabilistic mixture-based image modelling

    Czech Academy of Sciences Publication Activity Database

    Haindl, Michal; Havlíček, Vojtěch; Grim, Jiří

    2011-01-01

    Roč. 47, č. 3 (2011), s. 482-500 ISSN 0023-5954 R&D Projects: GA MŠk 1M0572; GA ČR GA102/08/0593 Grant - others:CESNET(CZ) 387/2010; GA MŠk(CZ) 2C06019; GA ČR(CZ) GA103/11/0335 Institutional research plan: CEZ:AV0Z10750506 Keywords : BTF texture modelling * discrete distribution mixtures * Bernoulli mixture * Gaussian mixture * multi-spectral texture modelling Subject RIV: BD - Theory of Information Impact factor: 0.454, year: 2011 http://library.utia.cas.cz/separaty/2011/RO/haindl-0360244.pdf

  17. Principles and practice of mixtures toxicology

    National Research Council Canada - National Science Library

    Mumtaz, Moiz

    2010-01-01

    ... accurate predictions for the adverse effects of mixtures has been limited by the difficulty of acquiring data for all the possible combinations of dose and time that exist even in simple mixtures. Such predictions are also compromised by our use of single-agent toxicity studies since most "realworld" exposures are to mixtures. This has resulted in a variety of approaches (models, protocols, techniques, etc.) to address these issues. These are described in detail in the two dozen chapters of this book along with ca...

  18. Adsorption on mixtures of ion exchangers

    International Nuclear Information System (INIS)

    Triolo, R.; Lietzke, M.H.

    1979-01-01

    A theoretical study has been made of adsorption on mixtures of ion exchangers. The effect of variables such as the concentration of the ion being adsorbed, the concentration of the supporting electrolyte, loading, the values of the capacities and equilibrium constants for the various exchange processes, and the fraction of each adsorber in the mixture on the observed distribution coefficient has been investigated. A computer program has been written to facilitate the calculation of distribution coefficients for the adsorption of an ion on a given mixture of ion exchangers under a specified set of conditions

  19. IGNITION IMPROVEMENT OF LEAN NATURAL GAS MIXTURES

    Energy Technology Data Exchange (ETDEWEB)

    Jason M. Keith

    2005-02-01

    This report describes work performed during a thirty month project which involves the production of dimethyl ether (DME) on-site for use as an ignition-improving additive in a compression-ignition natural gas engine. A single cylinder spark ignition engine was converted to compression ignition operation. The engine was then fully instrumented with a cylinder pressure transducer, crank shaft position sensor, airflow meter, natural gas mass flow sensor, and an exhaust temperature sensor. Finally, the engine was interfaced with a control system for pilot injection of DME. The engine testing is currently in progress. In addition, a one-pass process to form DME from natural gas was simulated with chemical processing software. Natural gas is reformed to synthesis gas (a mixture of hydrogen and carbon monoxide), converted into methanol, and finally to DME in three steps. Of additional benefit to the internal combustion engine, the offgas from the pilot process can be mixed with the main natural gas charge and is expected to improve engine performance. Furthermore, a one-pass pilot facility was constructed to produce 3.7 liters/hour (0.98 gallons/hour) DME from methanol in order to characterize the effluent DME solution and determine suitability for engine use. Successful production of DME led to an economic estimate of completing a full natural gas-to-DME pilot process. Additional experimental work in constructing a synthesis gas to methanol reactor is in progress. The overall recommendation from this work is that natural gas to DME is not a suitable pathway to improved natural gas engine performance. The major reasons are difficulties in handling DME for pilot injection and the large capital costs associated with DME production from natural gas.

  20. Structural investigation of aroylhydrazones in dimethylsulphoxide/water mixtures

    Science.gov (United States)

    Galić, Nives; Dijanošić, Adriana; Kontrec, Darko; Miljanić, Snežana

    Molecular structures of aroylhydrazones derived from salicylaldehyde, o-vanilin and nicotinic acid hydrazide in DMSO and DMSO/H2O mixtures have been studied by NMR, UV-Vis, ATR and Raman spectroscopy. The addition of water to the system did not induce the tautomeric conversion of the existing form constituted of the ketoamino hydrazide part and the enolimino aldehyde part, but it was involved in the formation of hydrated molecules. Vibrational spectra (ATR and Raman) clearly indicated hydrogen bonding of the studied hydrazones through the carbonyl, amino and hydroxyl groups with water molecules. Increasing the water content conversion from E to Z isomer was not observed.

  1. Detonation of hydrogen-air mixtures. [PWR; BWR

    Energy Technology Data Exchange (ETDEWEB)

    Lee, J.H.S.; Knystautas, R.; Benedick, W.B.

    1983-01-01

    The detonation of a hydrogen-air cloud subsequent to an accidental release of hydrogen into ambient surroundings cannot be totally ruled out in view of the relative sensitivity of the hydrogen-air system. The present paper investigates the key parameters involved in hydrogen-air detonations and attempts to establish quantitative correlations between those that have important practical implications. Thus, for example, the characteristic length scale lambda describing the cellular structure of a detonation front is measured for a broad range of hydrogen-air mixtures and is quantitatively correlated with the key dynamic detonation properties such as detonability, transmission and initiation.

  2. Eye Involvement in TSC

    Science.gov (United States)

    ... Privacy Policy Sitemap Learn Engage Donate About TSC Eyes Campbell (1905) first described the eye involvement in ... some form of eye involvement. Nonretinal and Retinal Eye Findings Facial angiofibromas may involve the eyelids of ...

  3. Quantitative characterization of microstructure of asphalt mixtures

    Science.gov (United States)

    2010-10-01

    The microstructure of the fine aggregate matrix has a significant influence on the : mechanical properties and evolution of damage in an asphalt mixture. However, very little : work has been done to define and quantitatively characterize the microstr...

  4. Structural design parameters of current WSDOT mixtures.

    Science.gov (United States)

    2013-06-01

    The AASHTO LRFD, as well as other design manuals, has specifications that estimate the structural performance of a concrete mixture with regard to compressive strength, tensile strength, and deformation-related properties such as the modulus of elast...

  5. Model structure selection in convolutive mixtures

    DEFF Research Database (Denmark)

    Dyrholm, Mads; Makeig, S.; Hansen, Lars Kai

    2006-01-01

    The CICAAR algorithm (convolutive independent component analysis with an auto-regressive inverse model) allows separation of white (i.i.d) source signals from convolutive mixtures. We introduce a source color model as a simple extension to the CICAAR which allows for a more parsimonious represent......The CICAAR algorithm (convolutive independent component analysis with an auto-regressive inverse model) allows separation of white (i.i.d) source signals from convolutive mixtures. We introduce a source color model as a simple extension to the CICAAR which allows for a more parsimonious...... representation in many practical mixtures. The new filter-CICAAR allows Bayesian model selection and can help answer questions like: ’Are we actually dealing with a convolutive mixture?’. We try to answer this question for EEG data....

  6. Modelling of an homogeneous equilibrium mixture model

    International Nuclear Information System (INIS)

    Bernard-Champmartin, A.; Poujade, O.; Mathiaud, J.; Mathiaud, J.; Ghidaglia, J.M.

    2014-01-01

    We present here a model for two phase flows which is simpler than the 6-equations models (with two densities, two velocities, two temperatures) but more accurate than the standard mixture models with 4 equations (with two densities, one velocity and one temperature). We are interested in the case when the two-phases have been interacting long enough for the drag force to be small but still not negligible. The so-called Homogeneous Equilibrium Mixture Model (HEM) that we present is dealing with both mixture and relative quantities, allowing in particular to follow both a mixture velocity and a relative velocity. This relative velocity is not tracked by a conservation law but by a closure law (drift relation), whose expression is related to the drag force terms of the two-phase flow. After the derivation of the model, a stability analysis and numerical experiments are presented. (authors)

  7. Adaptive estimation of Raman chemical mixture spectra

    Science.gov (United States)

    Burr, David J.; Chen, Carl G.; Sedlacek, Arthur J., III

    1996-11-01

    We introduce an adaptive mixing algorithm for estimating the relative ratios of chemicals in a mixture spectrum. This procedure is particularly well suited to mixtures with a large dynamic range of mixture weights. It has the advantage of being able to be used in conjunction with a band-pass (difference-to-Gaussian or DOG) filter, and a correction of baseline off-set and tilting of the spectrum. Output of these filtering techniques is a cleaner signal retaining most of the relevant Raman spectral signature while minimizing artifacts due primarily to Rayleigh, dust, and atmospheric aerosols. We will describe the results of applying these algorithm to mixture spectra with both real and simulated additive noise.

  8. Quantiles for Finite Mixtures of Normal Distributions

    Science.gov (United States)

    Rahman, Mezbahur; Rahman, Rumanur; Pearson, Larry M.

    2006-01-01

    Quantiles for finite mixtures of normal distributions are computed. The difference between a linear combination of independent normal random variables and a linear combination of independent normal densities is emphasized. (Contains 3 tables and 1 figure.)

  9. Mixture design procedure for flexible base.

    Science.gov (United States)

    2013-04-01

    This document provides information on mixture design requirements for a flexible base course. Sections : design requirements, job mix formula, contractor's responsibility, and engineer's responsibility. Tables : material requirements; requirements fo...

  10. Composition of nonflowing impregnating cable mixture

    Energy Technology Data Exchange (ETDEWEB)

    Dimitrov, D.M.; Andreyev, V.G.; Koralski, G.I.; Petkova, N.; Velikova, D.G.

    1979-08-10

    A composition of a nonflowing electrical insulation cable mixture is patented which is based on petroleum oil, colophony, polyolefinic wax, polyethylene and ceresine containing 1-20 percent per mixture of butadiene-styrol latex. Example (parts by weight). Cable impregnating oil has the following composition: colophony 5, petroleum oil 7.7, butadiene-styrol latex 5.0, polyolefin wax 10, low pressure polyethylene 3. In order to obtain a mixture latex is added to petroleum oil heated to 80 degrees, the mixture is heated to 110 degrees, and then to 130 degrees and the other components are added as it is vigorously mixed. The oil obtained features the following properties: drop point 110 degrees, penetration at 25 degrees 142, specific volumetric resistance at 80 degrees 1.485 x 10 13, angle of dielectric losses 0.0049, dielectric strength at 20 degrees 240 kW/cm.

  11. Predicting skin permeability from complex chemical mixtures.

    Science.gov (United States)

    Riviere, Jim E; Brooks, James D

    2005-10-15

    Occupational and environmental exposure to topical chemicals is usually in the form of complex chemical mixtures, yet risk assessment is based on experimentally derived data from individual chemical exposures from a single, usually aqueous vehicle, or from computed physiochemical properties. We present an approach using hybrid quantitative structure permeation relationships (QSPeR) models where absorption through porcine skin flow-through diffusion cells is well predicted using a QSPeR model describing the individual penetrants, coupled with a mixture factor (MF) that accounts for physicochemical properties of the vehicle/mixture components. The baseline equation is log k(p) = c + mMF + a sigma alpha2(H) + b sigma beta2(H) + s pi2(H) + rR2 + vV(x) where sigma alpha2(H) is the hydrogen-bond donor acidity, sigma beta2(H) is the hydrogen-bond acceptor basicity, pi2(H) is the dipolarity/polarizability, R2 represents the excess molar refractivity, and V(x) is the McGowan volume of the penetrants of interest; c, m, a, b, s, r, and v are strength coefficients coupling these descriptors to skin permeability (k(p)) of 12 penetrants (atrazine, chlorpyrifos, ethylparathion, fenthion, methylparathion, nonylphenol, rho-nitrophenol, pentachlorophenol, phenol, propazine, simazine, and triazine) in 24 mixtures. Mixtures consisted of full factorial combinations of vehicles (water, ethanol, propylene glycol) and additives (sodium lauryl sulfate, methyl nicotinate). An additional set of 4 penetrants (DEET, SDS, permethrin, ricinoleic acid) in different mixtures were included to assess applicability of this approach. This resulted in a dataset of 16 compounds administered in 344 treatment combinations. Across all exposures with no MF, R2 for absorption was 0.62. With the MF, correlations increased up to 0.78. Parameters correlated to the MF include refractive index, polarizability and log (1/Henry's Law Constant) of the mixture components. These factors should not be considered final

  12. Flash evaporation of liquid monomer particle mixture

    Science.gov (United States)

    Affinito, John D.; Darab, John G.; Gross, Mark E.

    1999-01-01

    The present invention is a method of making a first solid composite polymer layer. The method has the steps of (a) mixing a liquid monomer with particles substantially insoluble in the liquid monomer forming a monomer particle mixture; (b) flash evaporating the particle mixture and forming a composite vapor; and (c) continuously cryocondensing said composite vapor on a cool substrate and cross-linking the cryocondensed film thereby forming the polymer layer.

  13. Isotope mixtures of hydrogen in vanadium

    International Nuclear Information System (INIS)

    Mecking-Schloetensack, P.

    1982-03-01

    The properties of isotope-mixtures of Protium and Deuterium stored in Vanadium have been studied. Protium and Deuterium are existing as interstitial-atoms on tetrahedral sites as well as on octahedral sites in this system. This feature leads to large isotopic-effects between the two isotopes. The dependence of the thermodynamic functions like heat of solution, nonconfigurational entropy, specific heat and ordering temperatures from the composition of the isotope-mixture has been determined. (orig.)

  14. Using Big Data Analytics to Address Mixtures Exposure

    Science.gov (United States)

    The assessment of chemical mixtures is a complex issue for regulators and health scientists. We propose that assessing chemical co-occurrence patterns and prevalence rates is a relatively simple yet powerful approach in characterizing environmental mixtures and mixtures exposure...

  15. A Dirichlet process mixture of generalized Dirichlet distributions for proportional data modeling.

    Science.gov (United States)

    Bouguila, Nizar; Ziou, Djemel

    2010-01-01

    In this paper, we propose a clustering algorithm based on both Dirichlet processes and generalized Dirichlet distribution which has been shown to be very flexible for proportional data modeling. Our approach can be viewed as an extension of the finite generalized Dirichlet mixture model to the infinite case. The extension is based on nonparametric Bayesian analysis. This clustering algorithm does not require the specification of the number of mixture components to be given in advance and estimates it in a principled manner. Our approach is Bayesian and relies on the estimation of the posterior distribution of clusterings using Gibbs sampler. Through some applications involving real-data classification and image databases categorization using visual words, we show that clustering via infinite mixture models offers a more powerful and robust performance than classic finite mixtures.

  16. Toxic effects of pesticide mixtures at a molecular level: Their relevance to human health

    International Nuclear Information System (INIS)

    Hernández, Antonio F.; Parrón, Tesifón; Tsatsakis, Aristidis M.; Requena, Mar; Alarcón, Raquel; López-Guarnido, Olga

    2013-01-01

    Highlights: ► Toxic effects of pesticide mixtures can be independent, dose addition or interaction. ► Metabolic interactions involve inhibition or induction of detoxifying enzymes. ► Organophosphates can potentiate pyrethroid, carbaryl and triazine toxicity. ► Synergism occurs when two active pesticides elicit greater than additive toxicity. ► Endocrine disruptors have the potential for additivity rather than synergism. - Abstract: Pesticides almost always occur in mixtures with other ones. The toxicological effects of low-dose pesticide mixtures on the human health are largely unknown, although there are growing concerns about their safety. The combined toxicological effects of two or more components of a pesticide mixture can take one of three forms: independent, dose addition or interaction. Not all mixtures of pesticides with similar chemical structures produce additive effects; thus, if they act on multiple sites their mixtures may produce different toxic effects. The additive approach also fails when evaluating mixtures that involve a secondary chemical that changes the toxicokinetics of the pesticide as a result of its increased activation or decreased detoxification, which is followed by an enhanced or reduced toxicity, respectively. This review addresses a number of toxicological interactions of pesticide mixtures at a molecular level. Examples of such interactions include the postulated mechanisms for the potentiation of pyrethroid, carbaryl and triazine herbicides toxicity by organophosphates; how the toxicity of some organophosphates can be potentiated by other organophosphates or by previous exposure to organochlorines; the synergism between pyrethroid and carbamate compounds and the antagonism between triazine herbicides and prochloraz. Particular interactions are also addressed, such as those of pesticides acting as endocrine disruptors, the cumulative toxicity of organophosphates and organochlorines resulting in estrogenic effects and the

  17. Existence of the dielectric constant in dipolar fluid mixtures

    International Nuclear Information System (INIS)

    Ramshaw, J.D.; Hamer, N.D.

    1981-01-01

    The existence of the dielectric constant epsilon is investigated for fluid mixtures of rigid polar molecules. The investigation is performed using the functional-derivative formalism for mixtures, and is closely analogous to that previously carried out for pure dipolar fluids [J. Chem. Phys. 68, 5199 (1978)]. Sufficient conditions for the existence of epsilon are obtained in terms of the direct correlation function matrix c/sub alphabeta/(12). It is found that epsilon exists if c/sub alphabeta/(12) depends only on relative positions and orientations, and becomes asymptotic to -theta/sub alphabeta/(12)/kT at long range, where theta/sub alphabeta/(12) is the dipole--dipole potential between a molecule of species α and one of species β. An expression for epsilon in terms of the short-range total correlation function matrix emerges automatically from the development. This expression is equivalent to an earlier result obtained by a different method. Expressions for epsilon in terms of c/sub alphabeta/(12) are derived for axially symmetric molecules and for molecules of arbitrary symmetry. In the former case, the expression involves the inverse of an N/sub c/ x N/sub c/ matrix, where N/sub c/ is the number of components in the mixture. This expression facilitates the evaluation of epsilon in the mean spherical approximation. For molecules of arbitrary symmetry, the expression for epsilon in terms of c/sub alphabeta/(12) involves the inverse of an N/sub c/ x N/sub c/ supermatrix, each element of which is a 3 x 3 matrix

  18. Microsiemens or Milligrams: Measures of Ionic Mixtures ...

    Science.gov (United States)

    In December of 2016, EPA released the Draft Field-Based Methods for Developing Aquatic Life Criteria for Specific Conductivity for public comment. Once final, states and authorized tribes may use these methods to derive field-based ecoregional ambient Aquatic Life Ambient Water Quality Criteria (AWQC) for specific conductivity (SC) in flowing waters. The methods provide flexible approaches for developing science-based SC criteria that reflect ecoregional or state specific factors. The concentration of a dissolved salt mixture can be measured in a number of ways including measurement of total dissolved solids, freezing point depression, refractive index, density, or the sum of the concentrations of individually measured ions. For the draft method, SC was selected as the measure because SC is a measure of all ions in the mixture; the measurement technology is fast, inexpensive, and accurate, and it measures only dissolved ions. When developing water quality criteria for major ions, some stakeholders may prefer to identify the ionic constituents as a measure of exposure instead of SC. A field-based method was used to derive example chronic and acute water quality criteria for SC and two anions a common mixture of ions (bicarbonate plus sulfate, [HCO3−] + [SO42−] in mg/L) that represent common mixtures in streams. These two anions are sufficient to model the ion mixture and SC (R2 = 0.94). Using [HCO3−] + [SO42−] does not imply that these two anions are the

  19. Coal-water mixture fuel burner

    Science.gov (United States)

    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.

  20. A constitutive theory of reacting electrolyte mixtures

    Science.gov (United States)

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

    2013-11-01

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

  1. Pattern formation in phase separating binary mixtures.

    Science.gov (United States)

    Sam, Ebie M; Hayase, Yumino; Auernhammer, Günter K; Vollmer, Doris

    2011-08-07

    We experimentally investigate the interplay of thermodynamics with hydrodynamics during phase separation of (quasi-) binary mixtures. Well defined patterns emerge while slowly crossing the cloud point curve. Depending on the material parameters of the experimental system, two distinct scenarios are observed. In quasi-binary mixtures of methanol-hexane patterns appear before macroscopic phase separation sets in. In course of time the patterns turn faint while the overall turbidity of the sample increases until the mixtures become completely turbid. We attribute this pattern formation to a latent heat induced instability resembling a Rayleigh-Bénard instability. This is confirmed by calorimetric data and an estimate of its Rayleigh number. Mixtures of C(4)E(1)-water doped with decane phase separate under heating. After passing the cloud point curve these mixtures first become homogenously turbid. While clearing up, pattern formation is observed. We attribute this type of pattern formation to an interfacial tension induced Bénard-Marangoni instability. The occurrence of the two scenarios is supported by the relevant dimensionless numbers. This journal is © the Owner Societies 2011

  2. GLIMMIX : Software for estimating mixtures and mixtures of generalized linear models

    NARCIS (Netherlands)

    Wedel, M

    2001-01-01

    GLIMMIX is a commercial WINDOWS-based computer program that implements the EM algorithm (Dempster, Laird and Rubin 1977) for the estimation of finite mixtures and mixtures of generalized linear models. The program allows for the specification of a number of distributions in the exponential family,

  3. Chemical Mixtures Health Risk Assessment: Overview of Exposure Assessment, Whole Mixtures Assessments; Basic Concepts

    Science.gov (United States)

    This problems-based, half-day, introductory workshop focuses on methods to assess health risks posed by exposures to chemical mixtures in the environment. Chemical mixtures health risk assessment methods continue to be developed and evolve to address concerns over health risks f...

  4. The Viscosity of Organic Liquid Mixtures

    Science.gov (United States)

    Len, C. W.; Trusler, J. P. M.; Vesovic, V.; Wakeham, W. A.

    2006-01-01

    The paper reports measurements of the viscosity and density of two heavy hydrocarbon mixtures, Dutrex and Arab Light Flashed Distillate (ALFD), and of their mixtures with hydrogen. The measurements have been carried out with a vibrating-wire device over a range of temperatures from 399 to 547 K and at pressures up to 20 MPa. Measurements have also been carried out on systems in which hydrogen at different concentrations has been dissolved in the liquids. The measurements have an estimated uncertainty of ±5% for viscosity and ±2% for density and represent the first results on these prototypical heavy hydrocarbons. The results reveal that the addition of hydrogen reduces both the density and viscosity of the original hydrocarbon mixture at a particular temperature and pressure.

  5. MICROBIAL QUALITY OF HONEY MIXTURE WITH POLLEN

    Directory of Open Access Journals (Sweden)

    Ján Mareček

    2011-02-01

    Full Text Available Normal 0 21 MicrosoftInternetExplorer4 The aim of this study was evaluation of microbial quality in raw materials (honey, pollen and evaluation of microbial quality in honey mixture with pollen (2.91 % and 3.85 % and also dynamics of microbial groups in honey mixtures with pollen after 14 days storage at the room temperature (approximately 25 °C and in cold store (8 °C. We used dilution plating method for testing of samples. Detections of total plate microbial count (aerobic and anaerobic microorganisms, sporulating bacteria, coliform bacteria, Bifidobacterium sp., Lactobacillus sp. and microscopic fungi were performed. In general, counts of microorganisms decreased in honey mixture with pollen compared to raw pollen and these counts increased compared to natural honey. Total plate count was 5.37 log KTJ.g-1 in pollen; 1.36 log KTJ.g-1 in honey; 2.97 log KTJ.g-1 in honey mixture with 2.91 % pollen and 2.04 log KTJ.g-1 in honey mixture with 3.85 % pollen. Coliform bacteria were detected in pollen (1.77 log KTJ.g-1. Then, we found coliform bacteria in one sample of honey mixtures with pollen (2.91 % - 1.00 log KTJ.g-1.Bifidobacterium species were detected only in raw pollen. We did not findLactobacillus sp. in any of the samples. Microscopic fungi were detected on two cultivating media. Yeasts were present in pollen sample (average 5.39 log KTJ.g-1, honey mixture with 2.91 % pollen (average 2.51 log KTJ.g-1 and honey mixture with 3.85 % pollen (average 1.58 log KTJ.g-1. Filamentous microscopic fungi were detectable in pollen (average 3.38 log KTJ.g-1, in honey (only on one medium: 1.00 log KTJ.g-1, in honey mixture with 2.91 % pollen (average 1.15 log KTJ.g-1 and in honey mixture with 3.85 % pollen (1.71 %. Raw pollen contained microscopic fungi as Absidiasp., Mucor sp., Alternaria sp. andEmericella nidulans. Honey mixture with 2.91 % pollen after storage (14 days contained lower microbial counts when compared with the sample

  6. Two-Microphone Separation of Speech Mixtures

    DEFF Research Database (Denmark)

    Pedersen, Michael Syskind; Wang, DeLiang; Larsen, Jan

    2008-01-01

    Separation of speech mixtures, often referred to as the cocktail party problem, has been studied for decades. In many source separation tasks, the separation method is limited by the assumption of at least as many sensors as sources. Further, many methods require that the number of signals within...... combined, independent component analysis (ICA) and binary time–frequency (T–F) masking. By estimating binary masks from the outputs of an ICA algorithm, it is possible in an iterative way to extract basis speech signals from a convolutive mixture. The basis signals are afterwards improved by grouping...... similar signals. Using two microphones, we can separate, in principle, an arbitrary number of mixed speech signals. We show separation results for mixtures with as many as seven speech signals under instantaneous conditions. We also show that the proposed method is applicable to segregate speech signals...

  7. Detonation velocity in poorly mixed gas mixtures

    Science.gov (United States)

    Prokhorov, E. S.

    2017-10-01

    The technique for computation of the average velocity of plane detonation wave front in poorly mixed mixture of gaseous hydrocarbon fuel and oxygen is proposed. Here it is assumed that along the direction of detonation propagation the chemical composition of the mixture has periodic fluctuations caused, for example, by layered stratification of gas charge. The technique is based on the analysis of functional dependence of ideal (Chapman-Jouget) detonation velocity on mole fraction (with respect to molar concentration) of the fuel. It is shown that the average velocity of detonation can be significantly (by more than 10%) less than the velocity of ideal detonation. The dependence that permits to estimate the degree of mixing of gas mixture basing on the measurements of average detonation velocity is established.

  8. PREPARATION OF CONDUCTING SOLID MIXTURES, Technical Report

    Energy Technology Data Exchange (ETDEWEB)

    Spokas, J. J.

    1978-07-31

    The application of conducting plastic mixtures to the fundamental problem of radiation Dosimetry is briefly reviewed. A particular approach to achieveing formulations with the necessary characteristics is decribed. A number of successful mixtures are defined for a number of different specific dosimetry situations. To obtain high quality stable materials requires intense blending·and working of the materials at elevated temperatures. One machine that succeeds in this task is the Shonka plastics mixer-extruder. The Shonka mixer is described in complete detail. The procedures used in preparing represeptative formulations with this device are presented. A number of properties of successful conducting mixtures so prepared are summarized. The conditions required for molding such material are given. Several special welding methods for specific application with these formulations have been devised and are described.

  9. Joint Bayesian analysis of forensic mixtures.

    Science.gov (United States)

    Pascali, Vince L; Merigioli, Sara

    2012-12-01

    Evaluation of series of PCR experiments referring to the same evidence is not infrequent in a forensic casework. This situation is met when 'series of results in mixture' (EPGs produced by reiterating PCR experiments over the same DNA mixture extract) have to be interpreted or when 'potentially related traces' (mixtures that can have contributors in common) require a combined interpretation. In these cases, there can be uncertainty on the genotype assignment, since: (a) more than one genotype combination fall under the same peak profile; (b) PCR preferential amplification alters pre-PCR allelic proportions; (c) other, more unpredictable technical problems (dropouts/dropins, etc.) take place. The uncertainty in the genotype assignment is in most cases addressed by empirical methods (selection of just one particular profile; extraction of consensual or composite profiles) that disregard part of the evidence. Genotype assignment should conversely take advantage from a joint Bayesian analysis (JBA) of all STRs peak areas generated at each experiment. This is the typical case of Bayesian analysis in which adoption of object-oriented Bayesian networks (OOBNs) could be highly helpful. Starting from experimentally designed mixtures, we created typical examples of 'series of results in mixture' of 'potentially related traces'. JBA was some administered to the whole peak area evidence, by specifically tailored OOBNs models, which enabled genotype assignment reflecting all the available evidence. Examples of a residual ambiguity in the genotype assignment came to light at assumed genotypes with partially overlapping alleles (for example: AB+AC→ABC). In the 'series of results in mixture', this uncertainty was in part refractory to the joint evaluation. Ambiguity was conversely dissipated at the 'potentially related' trace example, where the ABC allelic scheme at the first trace was interpreted together with other unambiguous combinations (ABCD; AB) at the related trace. We

  10. Organizing Patient Involvement

    DEFF Research Database (Denmark)

    Brehm Johansen, Mette

    Patient involvement has become a part of the political agenda in Danish healthcare. Patients are to be involved not only in questions and decisions relating to their own treatment and care – to involve patients in quality improvement has also become a political expectation of quality work in Danish...... hospitals. During the last 25 years, patient involvement and quality improvement have become connected in Danish healthcare policy. However, the ideal of involving patients in quality improvement is described in very general terms and with only few specific expectations of how it is to be carried out...... in practice, as I show in the thesis. In the patient involvement literature, the difficulties of getting patient involvement in quality improvement to have in an impact on the planning and development of healthcare services is, for example, ascribed to conceptual vagueness of patient involvement, differences...

  11. Separation of alcohols from organic liquid mixtures by pervaporation

    NARCIS (Netherlands)

    Park, Hyun-Chae

    1993-01-01

    In the chemical industry, distillation is generally the preferred technique to separate a liquid mixture. However some liquid mixtures such as azeotropic mixtures, close-boiling hydrocarbons, and various isomers are difficult to separate by simple distillation. For the separation of these mixtures

  12. 21 CFR 1310.12 - Exempt chemical mixtures.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 9 2010-04-01 2010-04-01 false Exempt chemical mixtures. 1310.12 Section 1310.12... CHEMICALS AND CERTAIN MACHINES § 1310.12 Exempt chemical mixtures. (a) The chemical mixtures meeting the... importation of listed chemicals contained in the exempt chemical mixture or the civil liability for unlawful...

  13. Productivity, botanical composition, and nutritive value of commercial pasture mixtures

    Science.gov (United States)

    Pastures in the northeastern USA often are planted to mixtures of grasses and legumes. There is limited public sector information on the performance of commercial forage mixtures. We evaluated a range of commercial pasture mixtures to determine if the number of species in a mixture affected yield an...

  14. Isotope mixture enrichment and equipment therefor

    International Nuclear Information System (INIS)

    Inchauspe, N.; Bearn, A. de.

    1973-01-01

    A mixture of isotopes of an element belonging to the third group-first subgroup, or the fourth group-first subgroup, or the sixth group-second subgroup, or the rare gases group of the periodic system in the gaseous phase is introduced into a chamber filled with a sorption medium showing fixation properties and with a damping gas, inert to the isotope mixture as well as to the sorption medium. The fraction enriched by the least adsorbed isotope may be trapped at the chamber output. (B.S.)

  15. Unfolding the potential of wheat cultivar mixtures

    DEFF Research Database (Denmark)

    Borg, J.; Kiær, Lars Pødenphant; Lecarpentier, C.

    2018-01-01

    Increasing the biodiversity of cropped plants is a key leverage for agroecology, aiming to replace chemical inputs by ecological processes and regulations. Cultivar mixtures are a straightforward way to increase within-crop diversity, but they have so far been poorly used by farmers and they are ......Increasing the biodiversity of cropped plants is a key leverage for agroecology, aiming to replace chemical inputs by ecological processes and regulations. Cultivar mixtures are a straightforward way to increase within-crop diversity, but they have so far been poorly used by farmers...

  16. in Binary Liquid Mixtures of Ethyl benzoate

    Directory of Open Access Journals (Sweden)

    Shaik Babu

    2012-01-01

    Full Text Available Ultrasonic velocity is measured at 2MHz frequency in the binary mixtures of Ethyl Benzoate with 1-Propanol, 1-Butanol, 1-Pentanol and theoretical values of ultrasonic velocity have been evaluated at 303K using Nomoto's relation, Impedance relation, Ideal mixture relation, Junjie's method and free length theory. Theoretical values are compared with the experimental values and the validity of the theories is checked by applying the chi-square test for goodness of fit and by calculating the average percentage error (APE. A good agreement has been found between experimental and Nomoto’s ultrasonic velocity.

  17. Thermophysical Properties of Fluids and Fluid Mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Sengers, Jan V.; Anisimov, Mikhail A.

    2004-05-03

    The major goal of the project was to study the effect of critical fluctuations on the thermophysical properties and phase behavior of fluids and fluid mixtures. Long-range fluctuations appear because of the presence of critical phase transitions. A global theory of critical fluctuations was developed and applied to represent thermodynamic properties and transport properties of molecular fluids and fluid mixtures. In the second phase of the project, the theory was extended to deal with critical fluctuations in complex fluids such as polymer solutions and electrolyte solutions. The theoretical predictions have been confirmed by computer simulations and by light-scattering experiments. Fluctuations in fluids in nonequilibrium states have also been investigated.

  18. Plasma assisted combustion of parafin mixture

    International Nuclear Information System (INIS)

    Nedybaliuk, O.A.; Chernyak, V.Ya.; Martysh, E.V.; Lisitchenko, T.E.; Vergun, O.Yu.; Orlovska, S.G.

    2013-01-01

    In this work the results of solid paraffin combustion with the aid of the plasma of transverse and rotational gliding arc studies are represented. The question of the additional activation of paraffin based solid fuels is examined. The mixture of n-paraffin and stearin in the solid state as the model of the solid paraffin based fuel is used. The plasma assisted combustion of this model is experimentally investigated. The voltage-current characteristics of discharge at the different regimes are measured. The population temperatures of excited rotational levels are determined. The flame temperature during the combustion of solid paraffin containing mixture is calculated

  19. Flows and chemical reactions in homogeneous mixtures

    CERN Document Server

    Prud'homme, Roger

    2013-01-01

    Flows with chemical reactions can occur in various fields such as combustion, process engineering, aeronautics, the atmospheric environment and aquatics. The examples of application chosen in this book mainly concern homogeneous reactive mixtures that can occur in propellers within the fields of process engineering and combustion: - propagation of sound and monodimensional flows in nozzles, which may include disequilibria of the internal modes of the energy of molecules; - ideal chemical reactors, stabilization of their steady operation points in the homogeneous case of a perfect mixture and c

  20. Synthesis of Magnetic Ultrafine Particles from a Ternary Gaseous Mixture Involving Cobalt Tricarbonyl Nitrosyl

    Czech Academy of Sciences Publication Activity Database

    Morita, H.; Sakano, H.; Murafa, Nataliya; Šubrt, Jan

    2014-01-01

    Roč. 27, č. 46 (2014), s. 477-483 ISSN 0914-9244 Institutional support: RVO:61388980 Keywords : gas phase photochemical reaction * magnetic ultrafine particle * cobalt tricarbonyl nitrosyl * tetraethylgermane * propenyltrimethylsilane Subject RIV: CA - Inorganic Chemistry Impact factor: 1.055, year: 2014

  1. Impact of Chemical Proportions on the Acute Neurotoxicity of a Mixture of Seven Carbamates in Rats

    Science.gov (United States)

    Environmental exposures generally involve multiple chemicals and pathways, and statistical methodologies now exist to evaluate interactions among any number of chemicals in defined mixtures. N-methyl carbamate pesticides are presumed to act through a common mode of action, that i...

  2. Development of a 4.75-mm (No. 4) NMS mixture : research project capsule.

    Science.gov (United States)

    2017-08-01

    The objective of this project is to develop a 4.75-mm NMAS asphalt mixture for Louisiana roads, which will involve establishing target criteria for aggregate gradations, volumetric properties (e.g., air voids, VMA, VFA, and dust-to-binder ratio) and ...

  3. Addition Table of Colours: Additive and Subtractive Mixtures Described Using a Single Reasoning Model

    Science.gov (United States)

    Mota, A. R.; Lopes dos Santos, J. M. B.

    2014-01-01

    Students' misconceptions concerning colour phenomena and the apparent complexity of the underlying concepts--due to the different domains of knowledge involved--make its teaching very difficult. We have developed and tested a teaching device, the addition table of colours (ATC), that encompasses additive and subtractive mixtures in a single…

  4. Substitution value of a mixture of rice milling by-products for maize in ...

    African Journals Online (AJOL)

    A 12 - week feeding trial involving 64 weaner rabbits in a completely randomized design was carried out to determine the substitution value of a mixture of rice milling by-products (in the ratio of 1:1:1:2 respectively for straw, husk, hull, and bran) for maize in the diets of New Zealand white type weaner rabbits at four ...

  5. Online learning of a Dirichlet process mixture of Beta-Liouville distributions via variational inference.

    Science.gov (United States)

    Fan, Wentao; Bouguila, Nizar

    2013-11-01

    A large class of problems can be formulated in terms of the clustering process. Mixture models are an increasingly important tool in statistical pattern recognition and for analyzing and clustering complex data. Two challenging aspects that should be addressed when considering mixture models are how to choose between a set of plausible models and how to estimate the model's parameters. In this paper, we address both problems simultaneously within a unified online nonparametric Bayesian framework that we develop to learn a Dirichlet process mixture of Beta-Liouville distributions (i.e., an infinite Beta-Liouville mixture model). The proposed infinite model is used for the online modeling and clustering of proportional data for which the Beta-Liouville mixture has been shown to be effective. We propose a principled approach for approximating the intractable model's posterior distribution by a tractable one-which we develop-such that all the involved mixture's parameters can be estimated simultaneously and effectively in a closed form. This is done through variational inference that enjoys important advantages, such as handling of unobserved attributes and preventing under or overfitting; we explain that in detail. The effectiveness of the proposed work is evaluated on three challenging real applications, namely facial expression recognition, behavior modeling and recognition, and dynamic textures clustering.

  6. The influence of water mixtures on the dermal absorption of glycol ethers

    International Nuclear Information System (INIS)

    Traynor, Matthew J.; Wilkinson, Simon C.; Williams, Faith M.

    2007-01-01

    Glycol ethers are solvents widely used alone and as mixtures in industrial and household products. Some glycol ethers have been shown to have a range of toxic effects in humans following absorption and metabolism to their aldehyde and acid metabolites. This study assessed the influence of water mixtures on the dermal absorption of butoxyethanol and ethoxyethanol in vitro through human skin. Butoxyethanol penetrated human skin up to sixfold more rapidly from aqueous solution (50%, 450 mg/ml) than from the neat solvent. Similarly penetration of ethoxyethanol was increased threefold in the presence of water (50%, 697 mg/ml). There was a corresponding increase in apparent permeability coefficient as the glycol ether concentration in water decreased. The maximum penetration rate of water also increased in the presence of both glycol ethers. Absorption through a synthetic membrane obeyed Fick's Law and absorption through rat skin showed a similar profile to human skin but with a lesser effect. The mechanisms for this phenomenon involves disruption of the stratum corneum lipid bilayer by desiccation by neat glycol ether micelles, hydration with water mixtures and the physicochemical properties of the glycol ether-water mixtures. Full elucidation of the profile of absorption of glycol ethers from mixtures is required for risk assessment of dermal exposure. This work supports the view that risk assessments for dermal contact scenarios should ideally be based on absorption data obtained for the relevant formulation or mixture and exposure scenario and that absorption derived from permeability coefficients may be inappropriate for water-miscible solvents

  7. Structure-reactivity modeling using mixture-based representation of chemical reactions.

    Science.gov (United States)

    Polishchuk, Pavel; Madzhidov, Timur; Gimadiev, Timur; Bodrov, Andrey; Nugmanov, Ramil; Varnek, Alexandre

    2017-09-01

    We describe a novel approach of reaction representation as a combination of two mixtures: a mixture of reactants and a mixture of products. In turn, each mixture can be encoded using an earlier reported approach involving simplex descriptors (SiRMS). The feature vector representing these two mixtures results from either concatenated product and reactant descriptors or the difference between descriptors of products and reactants. This reaction representation doesn't need an explicit labeling of a reaction center. The rigorous "product-out" cross-validation (CV) strategy has been suggested. Unlike the naïve "reaction-out" CV approach based on a random selection of items, the proposed one provides with more realistic estimation of prediction accuracy for reactions resulting in novel products. The new methodology has been applied to model rate constants of E2 reactions. It has been demonstrated that the use of the fragment control domain applicability approach significantly increases prediction accuracy of the models. The models obtained with new "mixture" approach performed better than those required either explicit (Condensed Graph of Reaction) or implicit (reaction fingerprints) reaction center labeling.

  8. Equivalence of internal and external mixture schemes of single scattering properties in vector radiative transfer.

    Science.gov (United States)

    Mukherjee, Lipi; Zhai, Peng-Wang; Hu, Yongxiang; Winker, David M

    2017-05-10

    Polarized radiation fields in a turbid medium are influenced by single-scattering properties of scatterers. It is common that media contain two or more types of scatterers, which makes it essential to properly mix single-scattering properties of different types of scatterers in the vector radiative transfer theory. The vector radiative transfer solvers can be divided into two basic categories: the stochastic and deterministic methods. The stochastic method is basically the Monte Carlo method, which can handle scatterers with different scattering properties explicitly. This mixture scheme is called the external mixture scheme in this paper. The deterministic methods, however, can only deal with a single set of scattering properties in the smallest discretized spatial volume. The single-scattering properties of different types of scatterers have to be averaged before they are input to deterministic solvers. This second scheme is called the internal mixture scheme. The equivalence of these two different mixture schemes of scattering properties has not been demonstrated so far. In this paper, polarized radiation fields for several scattering media are solved using the Monte Carlo and successive order of scattering (SOS) methods and scattering media contain two types of scatterers: Rayleigh scatterers (molecules) and Mie scatterers (aerosols). The Monte Carlo and SOS methods employ external and internal mixture schemes of scatterers, respectively. It is found that the percentage differences between radiances solved by these two methods with different mixture schemes are of the order of 0.1%. The differences of Q/I, U/I, and V/I are of the order of 10 -5 ∼10 -4 , where I, Q, U, and V are the Stokes parameters. Therefore, the equivalence between these two mixture schemes is confirmed to the accuracy level of the radiative transfer numerical benchmarks. This result provides important guidelines for many radiative transfer applications that involve the mixture of

  9. MixtureTree annotator: a program for automatic colorization and visual annotation of MixtureTree.

    Directory of Open Access Journals (Sweden)

    Shu-Chuan Chen

    Full Text Available The MixtureTree Annotator, written in JAVA, allows the user to automatically color any phylogenetic tree in Newick format generated from any phylogeny reconstruction program and output the Nexus file. By providing the ability to automatically color the tree by sequence name, the MixtureTree Annotator provides a unique advantage over any other programs which perform a similar function. In addition, the MixtureTree Annotator is the only package that can efficiently annotate the output produced by MixtureTree with mutation information and coalescent time information. In order to visualize the resulting output file, a modified version of FigTree is used. Certain popular methods, which lack good built-in visualization tools, for example, MEGA, Mesquite, PHY-FI, TreeView, treeGraph and Geneious, may give results with human errors due to either manually adding colors to each node or with other limitations, for example only using color based on a number, such as branch length, or by taxonomy. In addition to allowing the user to automatically color any given Newick tree by sequence name, the MixtureTree Annotator is the only method that allows the user to automatically annotate the resulting tree created by the MixtureTree program. The MixtureTree Annotator is fast and easy-to-use, while still allowing the user full control over the coloring and annotating process.

  10. Spinodal decomposition of chemically reactive binary mixtures

    Science.gov (United States)

    Lamorgese, A.; Mauri, R.

    2016-08-01

    We simulate the influence of a reversible isomerization reaction on the phase segregation process occurring after spinodal decomposition of a deeply quenched regular binary mixture, restricting attention to systems wherein material transport occurs solely by diffusion. Our theoretical approach follows a diffuse-interface model of partially miscible binary mixtures wherein the coupling between reaction and diffusion is addressed within the frame of nonequilibrium thermodynamics, leading to a linear dependence of the reaction rate on the chemical affinity. Ultimately, the rate for an elementary reaction depends on the local part of the chemical potential difference since reaction is an inherently local phenomenon. Based on two-dimensional simulation results, we express the competition between segregation and reaction as a function of the Damköhler number. For a phase-separating mixture with components having different physical properties, a skewed phase diagram leads, at large times, to a system converging to a single-phase equilibrium state, corresponding to the absolute minimum of the Gibbs free energy. This conclusion continues to hold for the critical phase separation of an ideally perfectly symmetric binary mixture, where the choice of final equilibrium state at large times depends on the initial mean concentration being slightly larger or less than the critical concentration.

  11. Semiparametric mixtures in case-controlstudies

    NARCIS (Netherlands)

    Murphy, S.A.; van der Vaart, A.W.

    2001-01-01

    We consider likelihood based inference in a class of logistic models for case-control studies with a partially observed covariate. The likelihood is a combination of a nonparametric mixture, a parametric likelihood, and an empirical likelihood. We prove the asymptotic normality of the maximum

  12. Quantification of complex mixtures by NMR

    NARCIS (Netherlands)

    Duynhoven, van J.P.M.; Velzen, van E.; Jacobs, D.M.

    2013-01-01

    NMR has firmly established itself as an analytical tool that can quantify analyte concentrations in complex mixtures in a rapid, cost-effective, accurate and precise manner. Here, the technological advances with respect to instrumentation, sample preparation, data acquisition and data processing

  13. Spectrometric mixture analysis: An unexpected wrinkle

    Indian Academy of Sciences (India)

    Administrator

    The resulting calculation is simple, and typically yields a determinant ratio which, at least for a small number of mixture components, .... nes, both caffeine and theobromine have acid–base equilibria that make their ultraviolet spectra poten- tially pH-dependent. For a quantitative application of Beer's law we must therefore ...

  14. Concrete mixture characterization. Cementitious barriers partnership

    Energy Technology Data Exchange (ETDEWEB)

    Langton, C. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Protiere, Yannick [SIMCO Technologies, Inc., Quebec (Canada)

    2014-12-01

    This report summarizes the characterization study performed on two concrete mixtures used for radioactive waste storage. Both mixtures were prepared with approximately 425 kg of binder. The testing protocol mostly focused on determining the transport properties of the mixtures; volume of permeable voids (porosity), diffusion coefficients, and water permeability were evaluated. Tests were performed after different curing durations. In order to obtain data on the statistical distribution of transport properties, the measurements after 2 years of curing were performed on 10+ samples. Overall, both mixtures exhibited very low tortuosities and permeabilities, a direct consequence of their low water-to-binder ratio and the use of supplementary cementitious materials. The data generated on 2-year old samples showed that porosity, tortuosity and permeability follow a normal distribution. Chloride ponding tests were also performed on test samples. They showed limited chloride ingress, in line with measured transport properties. These test results also showed that both materials react differently with chloride, a consequence of the differences in the binder chemical compositions.

  15. Bayesian mixture models for partially verified data

    DEFF Research Database (Denmark)

    Kostoulas, Polychronis; Browne, William J.; Nielsen, Søren Saxmose

    2013-01-01

    Bayesian mixture models can be used to discriminate between the distributions of continuous test responses for different infection stages. These models are particularly useful in case of chronic infections with a long latent period, like Mycobacterium avium subsp. paratuberculosis (MAP) infection...

  16. A Skew-Normal Mixture Regression Model

    Science.gov (United States)

    Liu, Min; Lin, Tsung-I

    2014-01-01

    A challenge associated with traditional mixture regression models (MRMs), which rest on the assumption of normally distributed errors, is determining the number of unobserved groups. Specifically, even slight deviations from normality can lead to the detection of spurious classes. The current work aims to (a) examine how sensitive the commonly…

  17. Toxicology of chemical mixtures: International perspective

    NARCIS (Netherlands)

    Feron, V.J.; Cassee, F.R.; Groten, J.P.

    1998-01-01

    This paper reviews major activities outside the United States on human health issues related to chemical mixtures. In Europe an international study group on combination effects has been formed and has started by defining synergism and antagonism. Successful research programs in Europe include the

  18. Methods and systems for deacidizing gaseous mixtures

    Science.gov (United States)

    Hu, Liang

    2010-05-18

    An improved process for deacidizing a gaseous mixture using phase enhanced gas-liquid absorption is described. The process utilizes a multiphasic absorbent that absorbs an acid gas at increased rate and leads to reduced overall energy costs for the deacidizing operation.

  19. The use of ternary mixtures in concrete.

    Science.gov (United States)

    2014-05-01

    This manual is a summary of the findings of a comprehensive study. Its purpose is to provide engineers with the information they need to make educated decisions on the use of ternary mixtures for constructing concrete structures. It discusses the eff...

  20. Advances in Chemical Mixtures Risk Methods

    Science.gov (United States)

    This presentation is an overview of emerging issues for dose addition in chemical mixtures risk assessment. It is intended to give the participants a perspective of recent developments in methods for dose addition. The workshop abstract is as follows:This problems-based, half-day...

  1. New developments in mixture toxicity parameters

    Energy Technology Data Exchange (ETDEWEB)

    Hermens, J.; Loon, W. van; Verhaar, H.; Leeuwen, K. van [Utrecht Univ. (Netherlands). Research Inst. of Toxicology

    1995-12-31

    The potential toxicological effects of complex organic mixtures in water are usually evaluated based on standard bioassays, chemical analyses or chemical assays such as Extractable Organic Halogen (EOX) content. There is a need for additional chemical and biochemical techniques which supply information on concentrations of chemicals and which can directly be translated into toxicological information. A major class of chemical pollutants in the environment consist out of baseline toxicity chemicals which act by narcosis. The major characteristic of effects (survival or growth inhibition) of mixtures of chemicals with baseline toxicity is that they are completely additive and occur at a fixed body burden. A parameter was recently developed which simulates bioaccumulation and which measures the total baseline toxicity of organic mixtures in water. The parameter is based on a simulation of bioconcentration and measurement of total molar concentrations via vapor pressure osmometry on a hydrophobic phase. In this presentation the results of the application of this procedure to effluents and surface water are presented. Moreover, the use of GC-MS as a technique for measuring total molar concentrations is presented. The results for total molar concentrations measured via vapor pressure osmometry and GS-MS are compared and both techniques essentially give the same answer. The application of the new approach in evaluating the effects of complex mixtures is discussed in the light of future developments.

  2. Mixture toxicity of PBT-like chemicals

    DEFF Research Database (Denmark)

    Syberg, Kristian; Dai, Lina; Ramskov, Tina

    beyond that of the individual components. Firstly, the effects of three chemicals with PBT-like properties (acetyl cedrene, pyrene and triclosan) was examined on the freshwater snail, Potamopyrgus antipodarum. Secondly, mixture bioaccumulation of the same three chemicals were assessed experimentally...

  3. The Coffee-Milk Mixture Problem Revisited

    Science.gov (United States)

    Marion, Charles F.

    2015-01-01

    This analysis of a problem that is frequently posed at professional development workshops, in print, and on the Web--the coffee-milk mixture riddle--illustrates the timeless advice of George Pólya's masterpiece on problem solving in mathematics, "How to Solve It." In his book, Pólya recommends that problems previously solved and put…

  4. Pool Boiling of Hydrocarbon Mixtures on Water

    Energy Technology Data Exchange (ETDEWEB)

    Boee, R.

    1996-09-01

    In maritime transport of liquefied natural gas (LNG) there is a risk of spilling cryogenic liquid onto water. The present doctoral thesis discusses transient boiling experiments in which liquid hydrocarbons were poured onto water and left to boil off. Composition changes during boiling are believed to be connected with the initiation of rapid phase transition in LNG spilled on water. 64 experimental runs were carried out, 14 using pure liquid methane, 36 using methane-ethane, and 14 using methane-propane binary mixtures of different composition. The water surface was open to the atmosphere and covered an area of 200 cm{sup 2} at 25 - 40{sup o}C. The heat flux was obtained by monitoring the change of mass vs time. The void fraction in the boiling layer was measured with a gamma densitometer, and a method for adapting this measurement concept to the case of a boiling cryogenic liquid mixture is suggested. Significant differences in the boil-off characteristics between pure methane and binary mixtures revealed by previous studies are confirmed. Pure methane is in film boiling, whereas the mixtures appear to enter the transitional boiling regime with only small amounts of the second component added. The results indicate that the common assumption that LNG will be in film boiling on water because of the high temperature difference, may be questioned. Comparison with previous work shows that at this small scale the results are influenced by the experimental apparatus and procedures. 66 refs., 76 figs., 28 tabs.

  5. Immunomodulatory Activity Of Saponin Mixture Isolated From ...

    African Journals Online (AJOL)

    An attempt has been made to assess the immunomodulatory activity of purified saponin mixture (PSM) isolated from the fruits of Lagenaria siceraria at three dose levels ranging from 50-150 mg/kg body weight in mice using haemagglutination antibody (HA) titre, delayed type hypersensitivity (DTH) and carbon clearance ...

  6. Mixture model analysis of complex samples

    NARCIS (Netherlands)

    Wedel, M; ter Hofstede, F; Steenkamp, JBEM

    1998-01-01

    We investigate the effects of a complex sampling design on the estimation of mixture models. An approximate or pseudo likelihood approach is proposed to obtain consistent estimates of class-specific parameters when the sample arises from such a complex design. The effects of ignoring the sample

  7. Spectrometric mixture analysis: An unexpected wrinkle

    Indian Academy of Sciences (India)

    The spectrometric analysis of a mixture of two chemically and spectroscopically similar compounds is illustrated for the simultaneous spectrometric determination of caffeine and theobromine, the primary stimulants in coffee and tea, based on their ultraviolet absorbances. Their analysis indicates that such measurements ...

  8. The development of a lower heat concrete mixture for mass concrete placement conditions

    Science.gov (United States)

    Crowley, Aaron Martin

    The hydration process of portland cement (PC) is exothermic; therefore, the thermal behavior of concrete has to be taken into consideration when placed in a large mass. The research presented involves a Tennessee Department of Transportation (TDOT) Class S (seal) portland cement concrete (PCC) which is used as a foundation seal during construction of bridge abutments and piers. A Class S PCC mixture meeting the 2006 TDOT specifications has the potential to generate excessive amounts of heat and induce thermal cracking in structural elements. The purpose of the study is to reduce the heat generation of a Class S PCC while maintaining adequate values of other engineering properties. Due to the possibility of underwater placement of a Class S PCC, reduction in the total cementing materials content were not considered in this study. Five candidate mixtures were used to compare against a typical TDOT Class S mixture. The five candidate Class S-LH (lower heat) mixtures were 45, 60, 70% Grade 120 slag substitutions for PC as well as two ternary mixtures containing Grade 120 slag and Class F fly ash. Ten batches of each mixture were produced. All plastic and hardened properties met TDOT 604.03 Class S requirements for analytical comparison. The 70% Grade 120 slag Class S-LH mixture was analytically superior for all hardened properties and at reducing heat generation. Since the 70% Grade 120 slag Class S-LH mixture proved to be superior in laboratory conditions; it was selected for further evaluation in the field testing portion of the research. The 70% Grade 120 slag mixture produced a significantly lower maximum temperature as well as a significantly lower maximum differential temperature than a TDOT Class S mixture with 20% Class C fly ash in side-by-side 18 cubic yard cube field placements. Research results and literature recommend that engineers should decide when mass concrete conditions are appropriate during construction practices. When mass concrete conditions are

  9. Estimation of Fuzzy Measures Using Covariance Matrices in Gaussian Mixtures

    Directory of Open Access Journals (Sweden)

    Nishchal K. Verma

    2012-01-01

    Full Text Available This paper presents a novel computational approach for estimating fuzzy measures directly from Gaussian mixtures model (GMM. The mixture components of GMM provide the membership functions for the input-output fuzzy sets. By treating consequent part as a function of fuzzy measures, we derived its coefficients from the covariance matrices found directly from GMM and the defuzzified output constructed from both the premise and consequent parts of the nonadditive fuzzy rules that takes the form of Choquet integral. The computational burden involved with the solution of λ-measure is minimized using Q-measure. The fuzzy model whose fuzzy measures were computed using covariance matrices found in GMM has been successfully applied on two benchmark problems and one real-time electric load data of Indian utility. The performance of the resulting model for many experimental studies including the above-mentioned application is found to be better and comparable to recent available fuzzy models. The main contribution of this paper is the estimation of fuzzy measures efficiently and directly from covariance matrices found in GMM, avoiding the computational burden greatly while learning them iteratively and solving polynomial equations of order of the number of input-output variables.

  10. Properties of Direct Coal Liquefaction Residue Modified Asphalt Mixture

    Directory of Open Access Journals (Sweden)

    Jie Ji

    2017-01-01

    Full Text Available The objectives of this paper are to use Direct Coal Liquefaction Residue (DLCR to modify the asphalt binders and mixtures and to evaluate the performance of modified asphalt mixtures. The dynamic modulus and phase angle of DCLR and DCLR-composite modified asphalt mixture were analyzed, and the viscoelastic properties of these modified asphalt mixtures were compared to the base asphalt binder SK-90 and Styrene-Butadiene-Styrene (SBS modified asphalt mixtures. The master curves of the asphalt mixtures were shown, and dynamic and viscoelastic behaviors of asphalt mixtures were described using the Christensen-Anderson-Marasteanu (CAM model. The test results show that the dynamic moduli of DCLR and DCLR-composite asphalt mixtures are higher than those of the SK-90 and SBS modified asphalt mixtures. Based on the viscoelastic parameters of CAM models of the asphalt mixtures, the high- and low-temperature performance of DLCR and DCLR-composite modified asphalt mixtures are obviously better than the SK-90 and SBS modified asphalt mixtures. In addition, the DCLR and DCLR-composite modified asphalt mixtures are more insensitive to the frequency compared to SK-90 and SBS modified asphalt mixtures.

  11. Generation of sub-part-per-billion gaseous volatile organic compounds at ambient temperature by headspace diffusion of aqueous standards through decoupling between ideal and nonideal Henry's law behavior.

    Science.gov (United States)

    Kim, Yong-Hyun; Kim, Ki-Hyun

    2013-05-21

    In the analysis of volatile organic compounds in air, the preparation of their gaseous standards at low (sub-ppb) concentration levels with high reliability is quite difficult. In this study, a simple dynamic headspace-based approach was evaluated as a means of generating vapor-phase volatile organic compounds from a liquid standard in an impinger at ambient temperature (25 °C). For a given sampling time, volatile organic compound vapor formed in the headspace was swept by bypassing the sweep gas through the impinger and collected four times in quick succession in separate sorbent tubes. In each experiment, a fresh liquid sample was used for each of the four sampling times (5, 10, 20, and 30 min) at a steady flow rate of 50 mL min(-1). The air-water partitioning at the most dynamic (earliest) sweeping stage was established initially in accord with ideal Henry's law, which was then followed by considerably reduced partitioning in a steady-state equilibrium (non-ideal Henry's law). The concentrations of gaseous volatile organic compounds, collected after the steady-state equilibrium, reached fairly constant values: for instance, the mole fraction of toluene measured at a sweeping interval of 10 and 30 min averaged 1.10 and 0.99 nmol mol(-1), respectively (after the initial 10 min sampling). In the second stage of our experiment, the effect of increasing the concentrations of liquid spiking standard was also examined by collecting sweep gas samples from two consecutive 10 min runs. The volatile organic compounds, collected in the first and second 10 min sweep gas samples, exhibited ideal and nonideal Henry's law behavior, respectively. From this observation, we established numerical relationships to predict the mole fraction (or mixing ratio) of each volatile organic compound in steady-state equilibrium in relation to the concentration of standard spiked into the system. This experimental approach can thus be used to produce sub-ppb levels of gaseous volatile organic

  12. Equivalence of truncated count mixture distributions and mixtures of truncated count distributions.

    Science.gov (United States)

    Böhning, Dankmar; Kuhnert, Ronny

    2006-12-01

    This article is about modeling count data with zero truncation. A parametric count density family is considered. The truncated mixture of densities from this family is different from the mixture of truncated densities from the same family. Whereas the former model is more natural to formulate and to interpret, the latter model is theoretically easier to treat. It is shown that for any mixing distribution leading to a truncated mixture, a (usually different) mixing distribution can be found so that the associated mixture of truncated densities equals the truncated mixture, and vice versa. This implies that the likelihood surfaces for both situations agree, and in this sense both models are equivalent. Zero-truncated count data models are used frequently in the capture-recapture setting to estimate population size, and it can be shown that the two Horvitz-Thompson estimators, associated with the two models, agree. In particular, it is possible to achieve strong results for mixtures of truncated Poisson densities, including reliable, global construction of the unique NPMLE (nonparametric maximum likelihood estimator) of the mixing distribution, implying a unique estimator for the population size. The benefit of these results lies in the fact that it is valid to work with the mixture of truncated count densities, which is less appealing for the practitioner but theoretically easier. Mixtures of truncated count densities form a convex linear model, for which a developed theory exists, including global maximum likelihood theory as well as algorithmic approaches. Once the problem has been solved in this class, it might readily be transformed back to the original problem by means of an explicitly given mapping. Applications of these ideas are given, particularly in the case of the truncated Poisson family.

  13. Efficient speaker verification using Gaussian mixture model component clustering.

    Energy Technology Data Exchange (ETDEWEB)

    De Leon, Phillip L. (New Mexico State University, Las Cruces, NM); McClanahan, Richard D.

    2012-04-01

    In speaker verification (SV) systems that employ a support vector machine (SVM) classifier to make decisions on a supervector derived from Gaussian mixture model (GMM) component mean vectors, a significant portion of the computational load is involved in the calculation of the a posteriori probability of the feature vectors of the speaker under test with respect to the individual component densities of the universal background model (UBM). Further, the calculation of the sufficient statistics for the weight, mean, and covariance parameters derived from these same feature vectors also contribute a substantial amount of processing load to the SV system. In this paper, we propose a method that utilizes clusters of GMM-UBM mixture component densities in order to reduce the computational load required. In the adaptation step we score the feature vectors against the clusters and calculate the a posteriori probabilities and update the statistics exclusively for mixture components belonging to appropriate clusters. Each cluster is a grouping of multivariate normal distributions and is modeled by a single multivariate distribution. As such, the set of multivariate normal distributions representing the different clusters also form a GMM. This GMM is referred to as a hash GMM which can be considered to a lower resolution representation of the GMM-UBM. The mapping that associates the components of the hash GMM with components of the original GMM-UBM is referred to as a shortlist. This research investigates various methods of clustering the components of the GMM-UBM and forming hash GMMs. Of five different methods that are presented one method, Gaussian mixture reduction as proposed by Runnall's, easily outperformed the other methods. This method of Gaussian reduction iteratively reduces the size of a GMM by successively merging pairs of component densities. Pairs are selected for merger by using a Kullback-Leibler based metric. Using Runnal's method of reduction, we

  14. Commericial Involvement in Intramurals.

    Science.gov (United States)

    Maas, Gerry

    Sport in general has long had ties with commercial interests, the most popular and widespread involving publicity. Intramural sports programs, however, have not cultivated many commercial involvements in publicity. The approach in intramural sports advertising is simple. A commercial interest pays for space or time in a given communication media…

  15. Conversational Involvement and Loneliness.

    Science.gov (United States)

    Bell, Robert A.

    1985-01-01

    Assessed the relationship of conversational involvement and loneliness among college students. Found that lonely participants in this study had lower rates of talkativeness, interruptions, and attention than the nonlonely; they were also perceived as less involved and less interpersonally attractive. (PD)

  16. Sequential biodegradation of TNT, RDX and HMX in a mixture.

    Science.gov (United States)

    Sagi-Ben Moshe, S; Ronen, Z; Dahan, O; Weisbrod, N; Groisman, L; Adar, E; Nativ, R

    2009-01-01

    We describe TNT's inhibition of RDX and HMX anaerobic degradation in contaminated soil containing indigenous microbial populations. Biodegradation of RDX or HMX alone was markedly faster than their degradation in a mixture with TNT, implying biodegradation inhibition by the latter. The delay caused by the presence of TNT continued even after its disappearance and was linked to the presence of its intermediate, tetranitroazoxytoluene. PCR-DGGE analysis of cultures derived from the soil indicated a clear reduction in microbial biomass and diversity with increasing TNT concentration. At high-TNT concentrations (30 and 90 mg/L), only a single band, related to Clostridium nitrophenolicum, was observed after 3 days of incubation. We propose that the mechanism of TNT inhibition involves a cytotoxic effect on the RDX- and HMX-degrading microbial population. TNT inhibition in the top active soil can therefore initiate rapid transport of RDX and HMX to the less active subsurface and groundwater.

  17. Crystallization of Carbon-Oxygen Mixtures in White Dwarf Stars

    International Nuclear Information System (INIS)

    Horowitz, C. J.; Schneider, A. S.; Berry, D. K.

    2010-01-01

    We determine the phase diagram for dense carbon-oxygen mixtures in white dwarf (WD) star interiors using molecular dynamics simulations involving liquid and solid phases. Our phase diagram agrees well with predictions from Ogata et al. and from Medin and Cumming and gives lower melting temperatures than Segretain et al. Observations of WD crystallization in the globular cluster NGC 6397 by Winget et al. suggest that the melting temperature of WD cores is close to that for pure carbon. If this is true, our phase diagram implies that the central oxygen abundance in these stars is less than about 60%. This constraint, along with assumptions about convection in stellar evolution models, limits the effective S factor for the 12 C(α,γ) 16 O reaction to S 300 ≤170 keV b.

  18. Conditional Density Approximations with Mixtures of Polynomials

    DEFF Research Database (Denmark)

    Varando, Gherardo; López-Cruz, Pedro L.; Nielsen, Thomas Dyhre

    2015-01-01

    Mixtures of polynomials (MoPs) are a non-parametric density estimation technique especially designed for hybrid Bayesian networks with continuous and discrete variables. Algorithms to learn one- and multi-dimensional (marginal) MoPs from data have recently been proposed. In this paper we introduce...... is found. We illustrate and study the methods using data sampled from known parametric distributions, and we demonstrate their applicability by learning models based on real neuroscience data. Finally, we compare the performance of the proposed methods with an approach for learning mixtures of truncated...... basis functions (MoTBFs). The empirical results show that the proposed methods generally yield models that are comparable to or significantly better than those found using the MoTBF-based method....

  19. Probabilistic Discrete Mixtures Colour Texture Models

    Czech Academy of Sciences Publication Activity Database

    Haindl, Michal; Havlíček, Vojtěch; Grim, Jiří

    2008-01-01

    Roč. 2008, č. 5197 (2008), s. 675-682 ISSN 0302-9743. [Iberoamerican Congress on Pattern Recognition /13./. Havana, 09.092008-12.09.2008] R&D Projects: GA AV ČR 1ET400750407; GA MŠk 1M0572; GA ČR GA102/07/1594; GA ČR GA102/08/0593 Grant - others:GA MŠk(CZ) 2C06019 Institutional research plan: CEZ:AV0Z10750506 Keywords : Discrete distribution mixtures * EM algorithm * texture modeling Subject RIV: BD - Theory of Information http://library.utia.cas.cz/separaty/2008/RO/haindl-havlicek-grim-probabilistic%20discrete%20mixtures%20colour%20texture%20models.pdf

  20. Sum of Bernoulli Mixtures: Beyond Conditional Independence

    Directory of Open Access Journals (Sweden)

    Taehan Bae

    2014-01-01

    Full Text Available We consider the distribution of the sum of Bernoulli mixtures under a general dependence structure. The level of dependence is measured in terms of a limiting conditional correlation between two of the Bernoulli random variables. The conditioning event is that the mixing random variable is larger than a threshold and the limit is with respect to the threshold tending to one. The large-sample distribution of the empirical frequency and its use in approximating the risk measures, value at risk and conditional tail expectation, are presented for a new class of models which we call double mixtures. Several illustrative examples with a Beta mixing distribution, are given. As well, some data from the area of credit risk are fit with the models, and comparisons are made between the new models and also the classical Beta-binomial model.

  1. NMRI Measurements of Flow of Granular Mixtures

    Science.gov (United States)

    Nakagawa, Masami; Waggoner, R. Allen; Fukushima, Eiichi

    1996-01-01

    We investigate complex 3D behavior of granular mixtures in shaking and shearing devices. NMRI can non-invasively measure concentration, velocity, and velocity fluctuations of flows of suitable particles. We investigate origins of wall-shear induced convection flow of single component particles by measuring the flow and fluctuating motion of particles near rough boundaries. We also investigate if a mixture of different size particles segregate into their own species under the influence of external shaking and shearing disturbances. These non-invasive measurements will reveal true nature of convecting flow properties and wall disturbance. For experiments in a reduced gravity environment, we will design a light weight NMR imager. The proof of principle development will prepare for the construction of a complete spaceborne system to perform experiments in space.

  2. Thermodynamic modeling of CO2 mixtures

    DEFF Research Database (Denmark)

    Bjørner, Martin Gamel

    Knowledge of the thermodynamic properties and phase equilibria of mixtures containing carbon dioxide (CO2) is important in several industrial processes such as enhanced oil recovery, carbon capture and storage, and supercritical extractions, where CO2 is used as a solvent. Despite this importance......, accurate predictions of the thermodynamic properties and phase equilibria of mixtures containing CO2 are challenging with classical models such as the Soave-Redlich-Kwong (SRK) equation of state (EoS). This is believed to be due to the fact, that CO2 has a large quadrupole moment which the classical models...... and with or without introducing an additional pure compound parameter. In the absence of quadrupolar compounds qCPA reduces to CPA, which itself reduces toSRK in the absence of association. As the number of adjustable parameters in thermodynamic models increase, the parameter estimation problem becomes increasingly...

  3. Construction of a 21-Component Layered Mixture Experiment Design

    Energy Technology Data Exchange (ETDEWEB)

    Piepel, Gregory F.; Cooley, Scott K.; Jones, Bradley

    2004-09-22

    This paper describes the solution to a unique and challenging mixture experiment design problem involving: (1) 19 and 21 components for two different parts of the design, (2) many single-component and multi-component constraints, (3) augmentation of existing data, (4) a layered design developed in stages, and (5) a no-candidate-point optimal design approach. The problem involved studying the liquidus temperature of spinel crystals as a function of nuclear waste glass composition. The statistical objective was to develop an experimental design by augmenting existing glasses with new nonradioactive and radioactive glasses chosen to cover the designated nonradioactive and radioactive experimental regions. The existing 144 glasses were expressed as 19-component nonradioactive compositions and then augmented with 40 new nonradioactive glasses. These included 8 glasses on the outer layer of the region, 27 glasses on an inner layer, 2 replicate glasses at the centroid, and one replicate each of three existing glasses. Then, the 144 + 40 = 184 glasses were expressed as 21-component radioactive compositions and augmented with 5 radioactive glasses. A D-optimal design algorithm was used to select the new outer layer, inner layer, and radioactive glasses. Several statistical software packages can generate D-optimal experimental designs, but nearly all require a set of candidate points (e.g., vertices) from which to select design points. The large number of components (19 or 21) and many constraints made it impossible to generate the huge number of vertices and other typical candidate points. JMP(R) was used to select design points without candidate points. JMP uses a coordinate-exchange algorithm modified for mixture experiments, which is discussed in the paper.

  4. Binary Gas Mixtures of Light Helium to Intensify Laminar Forced Convection in Round Tubes

    Science.gov (United States)

    Campo, Antonio; Chikh, Salah; Papari, Mohammad; Mobinipouya, Mahammad

    2007-11-01

    This paper addresses potential heat transfer enhancement of laminar gaseous flows inside tubes with constant wall temperatures. The goal is to investigate the capabilities of certain binary gas mixtures of light helium as the primary gas with nitrogen, oxygen, carbon dioxide, methane, sulfur hexafluoride and tetrafluoromethane as the secondary heavier gases. The velocity of the binary gas mixtures is fully established and the temperature develops from a uniform value. The thermophysical properties of the binary gas mixtures depend on the molar gas composition in the w-domain [0, 1]. The two case studies involve a low mean bulk temperature of 300 K and the other a high mean bulk temperature of 600 K, both sharing 1 atm. The two target parameters for analysis and design are the maximum heat transfer rate and the pressure drop at the optimal molar gas composition.

  5. Sequential Estimation of Mixtures in Diffusion Networks

    Czech Academy of Sciences Publication Activity Database

    Dedecius, Kamil; Reichl, Jan; Djurić, P. M.

    2015-01-01

    Roč. 22, č. 2 (2015), s. 197-201 ISSN 1070-9908 R&D Projects: GA ČR(CZ) GP14-06678P Institutional support: RVO:67985556 Keywords : distributed estimation * mixture models * bayesian inference Subject RIV: BB - Applied Statistics, Operational Research Impact factor: 1.661, year: 2015 http://library.utia.cas.cz/separaty/2014/AS/dedecius-0431479.pdf

  6. Texture modelling by discrete distribution mixtures

    Czech Academy of Sciences Publication Activity Database

    Grim, Jiří; Haindl, Michal

    2003-01-01

    Roč. 41, 3-4 (2003), s. 603-615 ISSN 0167-9473 R&D Projects: GA ČR GA102/00/0030; GA AV ČR KSK1019101 Institutional research plan: CEZ:AV0Z1075907 Keywords : discrete distribution mixtures * EM algorithm * texture modelling Subject RIV: JC - Computer Hardware ; Software Impact factor: 0.711, year: 2003

  7. Text document classification based on mixture models

    Czech Academy of Sciences Publication Activity Database

    Novovičová, Jana; Malík, Antonín

    2004-01-01

    Roč. 40, č. 3 (2004), s. 293-304 ISSN 0023-5954 R&D Projects: GA AV ČR IAA2075302; GA ČR GA102/03/0049; GA AV ČR KSK1019101 Institutional research plan: CEZ:AV0Z1075907 Keywords : text classification * text categorization * multinomial mixture model Subject RIV: BB - Applied Statistics, Operational Research Impact factor: 0.224, year: 2004

  8. Bioavailability and variability of biphasic insulin mixtures

    DEFF Research Database (Denmark)

    Søeborg, Tue; Rasmussen, Christian Hove; Mosekilde, Erik

    2012-01-01

    Absorption of subcutaneously administered insulin is associated with considerable variability. Some of this variability was quantitatively explained for both soluble insulin and insulin suspensions in a recent contribution to this journal (Søeborg et al., 2009). In the present article, the absorp...... mixtures. The results can be used in both the development of novel insulin products and in the planning of the treatment of insulin dependent diabetic patients....

  9. Nitrocarburising in ammonia-hydrocarbon gas mixtures

    DEFF Research Database (Denmark)

    Pedersen, Hanne; Christiansen, Thomas; Somers, Marcel A. J.

    2010-01-01

    The present work investigates the possibility of nitrocarburising in ammonia-acetylene-hydrogen and ammoniapropene- hydrogen gas mixtures, where unsaturated hydrocarbon gas is the carbon source during nitrocarburising. Consequently, nitrocarburising is carried out in a reducing atmosphere...... microscopy and X-ray diffraction analysis. It is shown that the use of unsaturated hydrocarbon gas in nitrocarburising processes is a viable alternative to traditional nitrocarburising methods....

  10. Nitrocarburizing in ammonia-hydrocarbon gas mixtures

    DEFF Research Database (Denmark)

    Pedersen, Hanne; Christiansen, Thomas; Somers, Marcel A. J.

    2011-01-01

    The present work investigates the possibility of nitrocarburising in ammonia-acetylene-hydrogen and ammonia-propene-hydrogen gas mixtures, where unsaturated hydrocarbon gas is the carbon source during nitrocarburising. Consequently, nitrocarburising is carried out in a reducing atmosphere...... microscopy and X-ray diffraction analysis. It is shown that the use of unsaturated hydrocarbon gas in nitrocarburising processes is a viable alternative to traditional nitrocarburising methods....

  11. Structure of cholesterol/ceramide monolayer mixtures

    DEFF Research Database (Denmark)

    Scheffer, L.; Solomonov, I.; Weygand, M.J.

    2005-01-01

    The structure of monolayers of cholesterol/ ceramide mixtures was investigated using grazing incidence x-ray diffraction, immunofluorescence, and atomic force microscopy techniques. Grazing incidence x-ray diffraction measurements showed the existence of a crystalline mixed phase of the two....... As ceramide incorporates the lipid backbone common to all sphingolipids, this arrangement may be relevant to the understanding of the molecular organization of lipid rafts....

  12. Modeling text with generalizable Gaussian mixtures

    DEFF Research Database (Denmark)

    Hansen, Lars Kai; Sigurdsson, Sigurdur; Kolenda, Thomas

    2000-01-01

    We apply and discuss generalizable Gaussian mixture (GGM) models for text mining. The model automatically adapts model complexity for a given text representation. We show that the generalizability of these models depends on the dimensionality of the representation and the sample size. We discuss ...... the relation between supervised and unsupervised learning in the test data. Finally, we implement a novelty detector based on the density model....

  13. Manufacturing cycle for pure neon-helium mixture production

    International Nuclear Information System (INIS)

    Batrakov, B.P.; Kravchenko, V.A.

    1980-01-01

    The manufacturing cycle for pure neon-helium mixture production with JA-300 nitrogen air distributing device has been developed. Gas mixture containing 2-3% of neon-helium mixture (the rest is mainly nitrogen 96-97%) is selected out of the cover of the JA-300 column condensator and enters the deflegmator under the 2.3-2.5 atm. pressure. The diflegmator presents a heat exchange apparatus in which at 78 K liquid nitrogen the condensation of nitrogen from the mixture of gases entering from the JA-300 column takes place. The enriched gas mixture containing 65-70% of neon-helium mixture and 30-35% of nitrogen goes out from the deflegmator. This enriched neon-helium mixture enters the gasgoeder for impure (65-70%) neon-helium mixture. Full cleaning of-neon helium mixture of nitrogen is performed by means of an adsorber. As adsorbent an activated coal has been used. Adsorption occurs at the 78 K temperature of liquid nitrogen and pressure P=0.1 atm. As activated coal cooled down to nitrogen temperature adsorbs nitrogen better than neon and helium, the nitrogen from the mixture is completely adsorbed. Pure neon-helium mixture from the adsorber comes into a separate gasgolder. In one campaign the cycle allows obtaining 2 m 3 of the mixture. The mixture contains 0.14% of nitrogen, 0.01% of oxygen and 0.06% of hydrogen

  14. Dye mixtures for ultrafast wavelength shifters

    International Nuclear Information System (INIS)

    Gangopadhyay, S.; Liu, L.; Palsule, C.; Borst, W.; Wigmans, R.

    1994-01-01

    Particle detectors based on scintillation processes have been used since the discovery of radium about 100 years ago. The fast signals that can be obtained with these detectors, although often considered a nice asset, were rarely essential for the success of experiments. However, the new generation of high energy particle accelerators require particle detectors with fast response time. The authors have produced fast wavelength shifters using mixtures of various Coumarin dyes with DCM in epoxy-polymers (DGEBA+HHPA) and measured the properties of these wavelength shifters. The particular mixtures were chosen because there is a substantial overlap between the emission spectrum of Coumarin and the absorption spectrum of DCM. The continuous wave and time-resolved fluorescence spectra have been studied as a function of component concentration to optimize the decay times, emission peaks and quantum yields. The mean decay times of these mixtures are in the range of 2.5--4.5 ns. The mean decay time increases with an increase in Coumarin concentration at a fixed DCM concentration or with a decrease in DCM concentration at a fixed Coumarin concentration. This indicates that the energy transfer is radiative at lower relative DCM concentrations and becomes non-radiative at higher DCM concentrations

  15. Non-Genomic Effects of Xenoestrogen Mixtures

    Science.gov (United States)

    Viñas, René; Jeng, Yow-Jiun; Watson, Cheryl S.

    2012-01-01

    Xenoestrogens (XEs) are chemicals derived from a variety of natural and anthropogenic sources that can interfere with endogenous estrogens by either mimicking or blocking their responses via non-genomic and/or genomic signaling mechanisms. Disruption of estrogens’ actions through the less-studied non-genomic pathway can alter such functional end points as cell proliferation, peptide hormone release, catecholamine transport, and apoptosis, among others. Studies of potentially adverse effects due to mixtures and to low doses of endocrine-disrupting chemicals have recently become more feasible, though few so far have included actions via the non-genomic pathway. Physiologic estrogens and XEs evoke non-monotonic dose responses, with different compounds having different patterns of actions dependent on concentration and time, making mixture assessments all the more challenging. In order to understand the spectrum of toxicities and their mechanisms, future work should focus on carefully studying individual and mixture components across a range of concentrations and cellular pathways in a variety of tissue types. PMID:23066391

  16. Non-Genomic Effects of Xenoestrogen Mixtures

    Directory of Open Access Journals (Sweden)

    Yow-Jiun Jeng

    2012-07-01

    Full Text Available Xenoestrogens (XEs are chemicals derived from a variety of natural and anthropogenic sources that can interfere with endogenous estrogens by either mimicking or blocking their responses via non-genomic and/or genomic signaling mechanisms. Disruption of estrogens’ actions through the less-studied non-genomic pathway can alter such functional end points as cell proliferation, peptide hormone release, catecholamine transport, and apoptosis, among others. Studies of potentially adverse effects due to mixtures and to low doses of endocrine-disrupting chemicals have recently become more feasible, though few so far have included actions via the non-genomic pathway. Physiologic estrogens and XEs evoke non-monotonic dose responses, with different compounds having different patterns of actions dependent on concentration and time, making mixture assessments all the more challenging. In order to understand the spectrum of toxicities and their mechanisms, future work should focus on carefully studying individual and mixture components across a range of concentrations and cellular pathways in a variety of tissue types.

  17. Gaussian Process-Mixture Conditional Heteroscedasticity.

    Science.gov (United States)

    Platanios, Emmanouil A; Chatzis, Sotirios P

    2014-05-01

    Generalized autoregressive conditional heteroscedasticity (GARCH) models have long been considered as one of the most successful families of approaches for volatility modeling in financial return series. In this paper, we propose an alternative approach based on methodologies widely used in the field of statistical machine learning. Specifically, we propose a novel nonparametric Bayesian mixture of Gaussian process regression models, each component of which models the noise variance process that contaminates the observed data as a separate latent Gaussian process driven by the observed data. This way, we essentially obtain a Gaussian process-mixture conditional heteroscedasticity (GPMCH) model for volatility modeling in financial return series. We impose a nonparametric prior with power-law nature over the distribution of the model mixture components, namely the Pitman-Yor process prior, to allow for better capturing modeled data distributions with heavy tails and skewness. Finally, we provide a copula-based approach for obtaining a predictive posterior for the covariances over the asset returns modeled by means of a postulated GPMCH model. We evaluate the efficacy of our approach in a number of benchmark scenarios, and compare its performance to state-of-the-art methodologies.

  18. Robustifying Bayesian nonparametric mixtures for count data.

    Science.gov (United States)

    Canale, Antonio; Prünster, Igor

    2017-03-01

    Our motivating application stems from surveys of natural populations and is characterized by large spatial heterogeneity in the counts, which makes parametric approaches to modeling local animal abundance too restrictive. We adopt a Bayesian nonparametric approach based on mixture models and innovate with respect to popular Dirichlet process mixture of Poisson kernels by increasing the model flexibility at the level both of the kernel and the nonparametric mixing measure. This allows to derive accurate and robust estimates of the distribution of local animal abundance and of the corresponding clusters. The application and a simulation study for different scenarios yield also some general methodological implications. Adding flexibility solely at the level of the mixing measure does not improve inferences, since its impact is severely limited by the rigidity of the Poisson kernel with considerable consequences in terms of bias. However, once a kernel more flexible than the Poisson is chosen, inferences can be robustified by choosing a prior more general than the Dirichlet process. Therefore, to improve the performance of Bayesian nonparametric mixtures for count data one has to enrich the model simultaneously at both levels, the kernel and the mixing measure. © 2016, The International Biometric Society.

  19. Computational aspects of N-mixture models.

    Science.gov (United States)

    Dennis, Emily B; Morgan, Byron J T; Ridout, Martin S

    2015-03-01

    The N-mixture model is widely used to estimate the abundance of a population in the presence of unknown detection probability from only a set of counts subject to spatial and temporal replication (Royle, 2004, Biometrics 60, 105-115). We explain and exploit the equivalence of N-mixture and multivariate Poisson and negative-binomial models, which provides powerful new approaches for fitting these models. We show that particularly when detection probability and the number of sampling occasions are small, infinite estimates of abundance can arise. We propose a sample covariance as a diagnostic for this event, and demonstrate its good performance in the Poisson case. Infinite estimates may be missed in practice, due to numerical optimization procedures terminating at arbitrarily large values. It is shown that the use of a bound, K, for an infinite summation in the N-mixture likelihood can result in underestimation of abundance, so that default values of K in computer packages should be avoided. Instead we propose a simple automatic way to choose K. The methods are illustrated by analysis of data on Hermann's tortoise Testudo hermanni. © 2014 The Authors Biometrics published by Wiley Periodicals, Inc. on behalf of International Biometric Society.

  20. Statistical mechanical theory of fluid mixtures

    Science.gov (United States)

    Zhao, Yueqiang; Wu, Zhengming; Liu, Weiwei

    2014-01-01

    A general statistical mechanical theory of fluid mixtures (liquid mixtures and gas mixtures) is developed based on the statistical mechanical expression of chemical potential of components in the grand canonical ensemble, which gives some new relationships between thermodynamic quantities (equilibrium ratio Ki, separation factor α and activity coefficient γi) and ensemble average potential energy u for one molecule. The statistical mechanical expressions of separation factor α and activity coefficient γi derived in this work make the fluid phase equilibrium calculations can be performed by molecular simulation simply and efficiently, or by the statistical thermodynamic approach (based on the saturated-vapor pressure of pure substance) that does not need microscopic intermolecular pair potential functions. The physical meaning of activity coefficient γi in the liquid phase is discussed in detail from a viewpoint of molecular thermodynamics. The calculated Vapor-Liquid Equilibrium (VLE) properties of argon-methane, methanol-water and n-hexane-benzene systems by this model fit well with experimental data in references, which indicates that this model is accurate and reliable in the prediction of VLE properties for small, large and strongly associating molecules; furthermore the statistical mechanical expressions of separation factor α and activity coefficient γi have good compatibility with classical thermodynamic equations and quantum mechanical COSMO-SAC approach.

  1. Ethane-xenon mixtures under shock conditions

    Science.gov (United States)

    Flicker, Dawn; Magyar, Rudolph; Root, Seth; Cochrane, Kyle; Mattsson, Thomas

    2015-06-01

    Mixtures of light and heavy elements arise in inertial confinement fusion and planetary science. We present results on the physics of molecular scale mixing through a validation study of equation of state (EOS) properties. Density functional theory molecular dynamics (DFT/QMD) at elevated-temperature and pressure is used to obtain the properties of pure xenon, ethane, and various compressed mixture compositions along their principal Hugoniots. To validate the QMD simulations, we performed high-precision shock compression experiments using Sandia's Z-Machine. A bond tracking analysis of the simulations correlates the sharp rise in the Hugoniot curve with completion of dissociation in ethane. DFT-based simulation results compare well with experimental data and are used to provide insight into the dissociation as a function of mixture composition. Interestingly, we find that the compression ratio for complete dissociation is similar for ethane, Xe-ethane, polymethyl-pentene, and polystyrene, suggesting that a limiting compression exists for C-C bonded systems. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Company, Security Administration under contract DE-AC04-94AL85000.

  2. Catalytic Pyrolysis of Waste Plastic Mixture

    Science.gov (United States)

    Sembiring, Ferdianta; Wahyu Purnomo, Chandra; Purwono, Suryo

    2018-03-01

    Inorganic waste especially plastics still become a major problem in many places. Low biodegradability of this materials causes the effort in recycling become very difficult. Most of the municipal solid waste (MSW) recycling facilities in developing country only use composting method to recover the organic fraction of the waste, while the inorganic fraction is still untreated. By pyrolysis, plastic waste can be treated to produce liquid fuels, flammable gas and chars. Reduction in volume and utilization of the liquid and gas as fuel are the major benefits of the process. By heat integration actually this process can become a self-sufficient system in terms of energy demand. However, the drawback of this process is usually due to the diverse type of plastic in the MSW creating low grade of liquid fuel and harmful gases. In this study, the mixture of plastics i.e. polypropylene (PP) and polyethylene terephthalate (PET) is treated using pyrolysis with catalyst in several operating temperature. PET is problematic to be treated using pyrolysis due to wax-like byproduct in liquid which may cause pipe clogging. The catalyst is the mixture of natural zeolite and bentonite which is able to handle PP and PET mixture feed to produce high grade liquid fuels in terms of calorific value and other fuel properties.

  3. Doctors' involvement in torture.

    Science.gov (United States)

    Jesper, Sonntag

    2008-01-01

    Doctors from both non-democratic and democratic countries are involved in torture. The majority of doctors involved in torture are doctors at risk. Doctors at risk might compromise their ethical duty towards patients for the following possible reasons: individual factors (such as career, economic or ideological reasons), threats, orders from a higher ranking officer, political initiatives, working in atrocity-producing situations or dual loyalty. In dual loyalty conflicts, factors that might compromise doctors' ethical obligations towards detainees/patients are: ideological totalitarianism, moral disengagement, victim blame, patriotism, individual factors or threats. Another important reason why doctors are involved in torture is that not all doctors are trained in addressing human rights issues of detainees. Torture survivors report that they have experienced doctors' involvement in torture and doctors themselves report that they have been involved in torture. Testimonies from both torture survivors and doctors demonstrate that the most common way doctors are involved is in the diagnosis/medical examination of torture survivors/prisoners. And it is common before, during and after torture. Both torture survivors and doctors state that doctors are involved during torture by treatment and direct participation. Doctors also falsify journals, certificates and reports. When doctors are involved in torture it has devastating consequences for both torture survivors and doctors. The consequences for the survivors can be mistrust of doctors, avoidance of seeking doctors' help and nightmares involving doctors. Mistrust and avoidance of doctors could be especially fatal to the survivor, as it could mean a survivor who is ill may not seek medical attention. When the unambiguous role of the doctor as the protector and helper of people is questioned, it affects the medical profession all over the world.

  4. IDEA and Family Involvement

    Directory of Open Access Journals (Sweden)

    Mehmet Emin Öztürk

    2017-01-01

    Full Text Available Individuals with Disabilities Education Act (IDEA gives many rights to parents with special needs in terms of involvement and participation. Given the importance of family involvement in the special education process, and federal legislation that increasingly mandated and supported such involvement over time, considerable research has focused on the multiple ways that relationships between schools and families in the special education decision making process have played out. Educational professionals should create a positive climate for CLD families so that they feel more comfortable and therefore are able to participate more authentically and meaningfully.

  5. Roles of biomarkers in evaluating interactions among mixtures of lead, cadmium and arsenic

    International Nuclear Information System (INIS)

    Wang Gensheng; Fowler, Bruce A.

    2008-01-01

    Human exposure to environmental chemicals is most correctly characterized as exposure to mixtures of these agents. The metals/metalloids, lead (Pb), cadmium (Cd), and arsenic (As), are among the leading toxic agents detected in the environment. Exposure to these elements, particularly at chronic low dose levels, is still a major public health concern. Concurrent exposure to Pb, Cd, or As may produce additive or synergistic interactions or even new effects that are not seen in single component exposures. Evaluating these interactions on a mechanistic basis is essential for risk assessment and management of metal/metalloid mixtures. This paper will review a number of individual studies that addressed interactions of these metals/metalloids in both experimental and human exposure studies with particular emphasis on biomarkers. In general, co-exposure to metal/metalloid mixtures produced more severe effects at both relatively high dose and low dose levels in a biomarker-specific manner. These effects were found to be mediated by dose, duration of exposure and genetic factors. While traditional endpoints, such as morphological changes and biochemical parameters for target organ toxicity, were effective measures for evaluating the toxicity of high dose metal/metalloid mixtures, biomarkers for oxidative stress, altered heme biosynthesis parameters, and stress proteins showed clear responses in evaluating toxicity of low dose metal/metalloid mixtures. Metallothionein, heat shock proteins, and glutathione are involved in regulating interactive effects of metal/metalloid mixtures at low dose levels. These findings suggest that further studies on interactions of these metal/metalloid mixtures utilizing biomarker endpoints are highly warranted

  6. Feasibility of soil-EFB mixtures as a filled barrier material for waste disposal site

    International Nuclear Information System (INIS)

    Kamarudin Samuding; Ismail Abustan; Mohd Tadza Abdul Rahman; Mohamed Hasnain Isa

    2010-01-01

    This paper present the results of laboratory experiment that is involved the characterization and removal efficiency test of soil-EFB (Empty Fruit Bunch) of oil palm mixture. In this study, soil samples were mixed with EFB at 10 % (EFB10), 30 % (EFB30), and 50 % (EFB50). The characterization included the physical and chemical properties of the soil-EFB mixture such as compaction behaviour, cation exchange capacity, permeability and its surface physical morphology. Batch Equilibrium Test was performed in order to determine the adsorption capability of the soil-EFB mixture with the heavy metals solution. Five solutions with different concentrations (2.5 mg/l, 5.0 mg/l, 7.5 mg/l, 10.0 mg/l and 12.5 mg/l) were used in this experiment. Base on the compaction test, the value of optimum water content was influence by the EFB introduced into the soil. This is due to the presence of hydroxyl group, which was probably attributed to absorb water. The permeability of the soil-EFB mixtures ranges from 2.4 x 10 -7 to 6.5 x 10 -7 cm/s meanwhile the Cation Exchange Capacity (CEC) result ranges from 11.6 to 31.9 meq/ 100 g. The study has revealed that different percentages of soil-EFB mixture possess different capabilities to remove heavy metals. From the removal efficiency test, it is shown that the removal percentages of heavy metals for soil-EFB mixtures were relatively high as compared to soil alone. Based on the characterization and removal data, the soil-EFB mixture has a good potential to be used as filled barrier material. (author)

  7. Ion swarm data for electrical discharge modeling in air and flue gas mixtures

    International Nuclear Information System (INIS)

    Nelson, D.; Benhenni, M.; Eichwald, O.; Yousfi, M.

    2003-01-01

    The first step of this work is the determination of the elastic and inelastic ion-molecule collision cross sections for the main ions (N 2 + , O 2 + , CO 2 + , H 2 O + and O - ) usually present either in the air or flue gas discharges. The obtained cross section sets, given for ion kinetic energies not exceeding 100 eV, correspond to the interactions of each ion with its parent molecule (symmetric case) or nonparent molecule (asymmetric case). Then by using these different cross section sets, it is possible to obtain the ion swarm data for the different gas mixtures involving N 2 , CO 2 , H 2 O and O 2 molecules whatever their relative proportions. These ion swarm data are obtained from an optimized Monte Carlo method well adapted for the ion transport in gas mixtures. This also allows us to clearly show that the classical linear approximations usually applied for the ion swarm data in mixtures such as Blanc's law are far to be valid. Then, the ion swarm data are given in three cases of gas mixtures: a dry air (80% N 2 , 20% O 2 ), a ternary gas mixture (82% N 2 , 12% CO 2 , 6% O 2 ) and a typical flue gas (76% N 2 , 12% CO 2 , 6% O 2 , 6% H 2 O). From these reliable ion swarm data, electrical discharge modeling for a wire to plane electrode configuration has been carried out in these three mixtures at the atmospheric pressure for different applied voltages. Under the same discharge conditions, large discrepancies in the streamer formation and propagation have been observed in these three mixture cases. They are due to the deviations existing not only between the different effective electron-molecule ionization rates but also between the ion transport properties mainly because of the presence of a highly polar molecule such as H 2 O. This emphasizes the necessity to properly consider the ion transport in the discharge modeling

  8. Presence of Trifolium repens Promotes Complementarity of Water Use and N Facilitation in Diverse Grass Mixtures.

    Science.gov (United States)

    Hernandez, Pauline; Picon-Cochard, Catherine

    2016-01-01

    Legume species promote productivity and increase the digestibility of herbage in grasslands. Considerable experimental data also indicate that communities with legumes produce more above-ground biomass than is expected from monocultures. While it has been attributed to N facilitation, evidence to identify the mechanisms involved is still lacking and the role of complementarity in soil water acquisition by vertical root differentiation remains unclear. We used a 20-months mesocosm experiment to investigate the effects of species richness (single species, two- and five-species mixtures) and functional diversity (presence of the legume Trifolium repens) on a set of traits related to light, N and water use and measured at community level. We found a positive effect of Trifolium presence and abundance on biomass production and complementarity effects in the two-species mixtures from the second year. In addition the community traits related to water and N acquisition and use (leaf area, N, water-use efficiency, and deep root growth) were higher in the presence of Trifolium. With a multiple regression approach, we showed that the traits related to water acquisition and use were with N the main determinants of biomass production and complementarity effects in diverse mixtures. At shallow soil layers, lower root mass of Trifolium and higher soil moisture should increase soil water availability for the associated grass species. Conversely at deep soil layer, higher root growth and lower soil moisture mirror soil resource use increase of mixtures. Altogether, these results highlight N facilitation but almost soil vertical differentiation and thus complementarity for water acquisition and use in mixtures with Trifolium. Contrary to grass-Trifolium mixtures, no significant over-yielding was measured for grass mixtures even those having complementary traits (short and shallow vs. tall and deep). Thus, vertical complementarity for soil resources uptake in mixtures was not only

  9. Presence of Trifolium repens promotes complementarity of water use and N facilitation in diverse grass mixtures

    Directory of Open Access Journals (Sweden)

    Pauline eHernandez

    2016-04-01

    Full Text Available Legume species promote productivity and increase the digestibility of herbage in grasslands. Considerable experimental data also indicate that communities with legumes produce more above-ground biomass than is expected from monocultures. While it has been attributed to N facilitation, evidence to identify the mechanisms involved is still lacking and the role of complementarity in soil water acquisition by vertical root differentiation remains unclear. We used a 20-month mesocosm experiment to investigate the effects of species richness (single species, two- and five-species mixtures and functional diversity (presence of the legume Trifolium repens on a set of traits related to light, N and water use and measured at community level. We found a positive effect of Trifolium presence and abundance on biomass production and complementarity effects in the two-species mixtures from the second year. In addition the community traits related to water and N acquisition and use (leaf area, N, water-use efficiency and deep root growth were higher in the presence of Trifolium. With a multiple regression approach, we showed that the traits related to water acquisition and use were with N the main determinants of biomass production and complementarity effects in diverse mixtures. At shallow soil layers, lower root mass of Trifolium and higher soil moisture should increase soil water availability for the associated grass species. Conversely at deep soil layer, higher root growth and lower soil moisture mirror soil resource use increase of mixtures. Altogether, these results highlight N facilitation but almost soil vertical differentiation and thus complementarity for water acquisition and use in mixtures with Trifolium. Contrary to grass-Trifolium mixtures, no significant over-yielding was measured for grass mixtures even those having complementary traits (short and shallow vs tall and deep. Thus, vertical complementarity for soil resources uptake in mixtures

  10. Separation of gas mixtures by supported complexes

    Energy Technology Data Exchange (ETDEWEB)

    Nelson, D.A.; Lilga, M.A.; Hallen, R.T.; Lyke, S.E.

    1986-08-01

    The goal of this program is to determine the feasibility of solvent-dissolved coordination complexes for the separation of gas mixtures under bench-scale conditions. In particular, mixtures such as low-Btu gas are examined for CO and H/sub 2/ separation. Two complexes, Pd/sub 2/(dpm)/sub 2/Br/sub 2/ and Ru(CO)/sub 2/(PPh/sub 3/)/sub 3/, were examined in a bench-scale apparatus for the separation of binary (CO-N/sub 2/ or H/sub 2/-N/sub 2/) and quinary (H/sub 2/, CO, CO/sub 2/, CH/sub 4/, and N/sub 2/) mixtures. The separation of CO-N/sub 2/ was enhanced by the presence of the palladium complex in the 1,1,2-trichloroethane (TCE) solvent, especially at high gas and low liquid rates. The five-component gas mixture separation with the palladium complex in TCE provided quite unexpected results based on physical solubility and chemical coordination. The complex retained CO, while the solvent retained CO/sub 2/, CH/sub 4/, and N/sub 2/ to varying degrees. This allowed the hydrogen content to be enhanced due to its low solubility in TCE and inertness to the complex. Thus, a one-step, hydrogen separation can be achieved from gas mixtures with compositions similar to that of oxygen-blown coal gas. A preliminary economic evaluation of hydrogen separation was made for a system based on the palladium complex. The palladium system has a separation cost of 50 to 60 cents/MSCF with an assumed capital investment of $1.60/MSCF of annual capacity charged at 30% per year. This assumes a 3 to 4 year life for the complex. Starting with a 90% hydrogen feed, PSA separation costs are in the range of 30 to 50 cents/MSCF. The ruthenium complex was not as successful for hydrogen or carbon monoxide separation due to unfavorable kinetics. The palladium complex was found to strip hydrogen gas from H/sub 2/S. The complex could be regenerated with mild oxidants which removed the sulfur as SO/sub 2/. 24 refs., 26 figs., 10 tabs.

  11. Chemical Mixture Risk Assessment Additivity-Based Approaches

    Science.gov (United States)

    Powerpoint presentation includes additivity-based chemical mixture risk assessment methods. Basic concepts, theory and example calculations are included. Several slides discuss the use of "common adverse outcomes" in analyzing phthalate mixtures.

  12. Implementation of warm-mix asphalt mixtures in Nebraska pavements.

    Science.gov (United States)

    2012-07-01

    The primary objective of this research is to evaluate the feasibility of several WMA mixtures as potential asphalt paving : mixtures for Nebraska pavements. To that end, three well-known WMA additives (i.e., Sasobit, Evotherm, and Advera : synthetic ...

  13. REFLEAK: NIST Leak/Recharge Simulation Program for Refrigerant Mixtures

    Science.gov (United States)

    SRD 73 NIST REFLEAK: NIST Leak/Recharge Simulation Program for Refrigerant Mixtures (PC database for purchase)   REFLEAK estimates composition changes of zeotropic mixtures in leak and recharge processes.

  14. Characterization of Alaskan HMA mixtures with the simple performance tester.

    Science.gov (United States)

    2014-05-01

    Material characterization provides basic and essential information for pavement design and the evaluation of hot mix asphalt (HMA). : This study focused on the accurate characterization of an Alaskan HMA mixture using an asphalt mixture performance t...

  15. Multivariate mixtures of Erlangs for density estimation under censoring

    NARCIS (Netherlands)

    Verbelen, R.; Antonio, K.; Claeskens, G.

    2016-01-01

    Multivariate mixtures of Erlang distributions form a versatile, yet analytically tractable, class of distributions making them suitable for multivariate density estimation. We present a flexible and effective fitting procedure for multivariate mixtures of Erlangs, which iteratively uses the EM

  16. Mixture Density Mercer Kernels: A Method to Learn Kernels

    Data.gov (United States)

    National Aeronautics and Space Administration — This paper presents a method of generating Mercer Kernels from an ensemble of probabilistic mixture models, where each mixture model is generated from a Bayesian...

  17. Performance evaluation of Louisiana superpave mixtures : tech summary.

    Science.gov (United States)

    2008-12-01

    The primary objective of this research was to evaluate the fundamental engineering : properties and mixture performance of Superpave hot mix asphalt (HMA) mixtures : in Louisiana through laboratory mechanistic tests, aggregate gradation analysis, and...

  18. Transesterification of waste vegetable oil under pulse sonication using ethanol, methanol and ethanol–methanol mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Martinez-Guerra, Edith; Gude, Veera Gnaneswar, E-mail: gude@cee.msstate.edu

    2014-12-15

    Highlights: • Pulse sonication effect on transesterification of waste vegetable oil was studied. • Effects of ethanol, methanol, and alcohol mixtures on FAMEs yield were evaluated. • Effect of ultrasonic intensity, power density, and its output rates were evaluated. • Alcohol mixtures resulted in higher biodiesel yields due to better solubility. - Abstract: This study reports on the effects of direct pulse sonication and the type of alcohol (methanol and ethanol) on the transesterification reaction of waste vegetable oil without any external heating or mechanical mixing. Biodiesel yields and optimum process conditions for the transesterification reaction involving ethanol, methanol, and ethanol–methanol mixtures were evaluated. The effects of ultrasonic power densities (by varying sample volumes), power output rates (in W), and ultrasonic intensities (by varying the reactor size) were studied for transesterification reaction with ethanol, methanol and ethanol–methanol (50%-50%) mixtures. The optimum process conditions for ethanol or methanol based transesterification reaction of waste vegetable oil were determined as: 9:1 alcohol to oil ratio, 1% wt. catalyst amount, 1–2 min reaction time at a power output rate between 75 and 150 W. It was shown that the transesterification reactions using ethanol–methanol mixtures resulted in biodiesel yields as high as >99% at lower power density and ultrasound intensity when compared to ethanol or methanol based transesterification reactions.

  19. Minimum Hellinger distance estimation for k-component poisson mixture with random effects.

    Science.gov (United States)

    Xiang, Liming; Yau, Kelvin K W; Van Hui, Yer; Lee, Andy H

    2008-06-01

    The k-component Poisson regression mixture with random effects is an effective model in describing the heterogeneity for clustered count data arising from several latent subpopulations. However, the residual maximum likelihood estimation (REML) of regression coefficients and variance component parameters tend to be unstable and may result in misleading inferences in the presence of outliers or extreme contamination. In the literature, the minimum Hellinger distance (MHD) estimation has been investigated to obtain robust estimation for finite Poisson mixtures. This article aims to develop a robust MHD estimation approach for k-component Poisson mixtures with normally distributed random effects. By applying the Gaussian quadrature technique to approximate the integrals involved in the marginal distribution, the marginal probability function of the k-component Poisson mixture with random effects can be approximated by the summation of a set of finite Poisson mixtures. Simulation study shows that the MHD estimates perform satisfactorily for data without outlying observation(s), and outperform the REML estimates when data are contaminated. Application to a data set of recurrent urinary tract infections (UTI) with random institution effects demonstrates the practical use of the robust MHD estimation method.

  20. Transesterification of waste vegetable oil under pulse sonication using ethanol, methanol and ethanol–methanol mixtures

    International Nuclear Information System (INIS)

    Martinez-Guerra, Edith; Gude, Veera Gnaneswar

    2014-01-01

    Highlights: • Pulse sonication effect on transesterification of waste vegetable oil was studied. • Effects of ethanol, methanol, and alcohol mixtures on FAMEs yield were evaluated. • Effect of ultrasonic intensity, power density, and its output rates were evaluated. • Alcohol mixtures resulted in higher biodiesel yields due to better solubility. - Abstract: This study reports on the effects of direct pulse sonication and the type of alcohol (methanol and ethanol) on the transesterification reaction of waste vegetable oil without any external heating or mechanical mixing. Biodiesel yields and optimum process conditions for the transesterification reaction involving ethanol, methanol, and ethanol–methanol mixtures were evaluated. The effects of ultrasonic power densities (by varying sample volumes), power output rates (in W), and ultrasonic intensities (by varying the reactor size) were studied for transesterification reaction with ethanol, methanol and ethanol–methanol (50%-50%) mixtures. The optimum process conditions for ethanol or methanol based transesterification reaction of waste vegetable oil were determined as: 9:1 alcohol to oil ratio, 1% wt. catalyst amount, 1–2 min reaction time at a power output rate between 75 and 150 W. It was shown that the transesterification reactions using ethanol–methanol mixtures resulted in biodiesel yields as high as >99% at lower power density and ultrasound intensity when compared to ethanol or methanol based transesterification reactions

  1. Mixtures of Chemical Pollutants at European Legislation Safety Concentrations: How Safe Are They?

    Science.gov (United States)

    Carvalho, Raquel N.; Arukwe, Augustine; Ait-Aissa, Selim; Bado-Nilles, Anne; Balzamo, Stefania; Baun, Anders; Belkin, Shimshon; Blaha, Ludek; Brion, François; Conti, Daniela; Creusot, Nicolas; Essig, Yona; Ferrero, Valentina E. V.; Flander-Putrle, Vesna; Fürhacker, Maria; Grillari-Voglauer, Regina; Hogstrand, Christer; Jonáš, Adam; Kharlyngdoh, Joubert B.; Loos, Robert; Lundebye, Anne-Katrine; Modig, Carina; Olsson, Per-Erik; Pillai, Smitha; Polak, Natasa; Potalivo, Monica; Sanchez, Wilfried; Schifferli, Andrea; Schirmer, Kristin; Sforzini, Susanna; Stürzenbaum, Stephen R.; Søfteland, Liv; Turk, Valentina; Viarengo, Aldo; Werner, Inge; Yagur-Kroll, Sharon; Zounková, Radka; Lettieri, Teresa

    2014-01-01

    The risk posed by complex chemical mixtures in the environment to wildlife and humans is increasingly debated, but has been rarely tested under environmentally relevant scenarios. To address this issue, two mixtures of 14 or 19 substances of concern (pesticides, pharmaceuticals, heavy metals, polyaromatic hydrocarbons, a surfactant, and a plasticizer), each present at its safety limit concentration imposed by the European legislation, were prepared and tested for their toxic effects. The effects of the mixtures were assessed in 35 bioassays, based on 11 organisms representing different trophic levels. A consortium of 16 laboratories was involved in performing the bioassays. The mixtures elicited quantifiable toxic effects on some of the test systems employed, including i) changes in marine microbial composition, ii) microalgae toxicity, iii) immobilization in the crustacean Daphnia magna, iv) fish embryo toxicity, v) impaired frog embryo development, and vi) increased expression on oxidative stress-linked reporter genes. Estrogenic activity close to regulatory safety limit concentrations was uncovered by receptor-binding assays. The results highlight the need of precautionary actions on the assessment of chemical mixtures even in cases where individual toxicants are present at seemingly harmless concentrations. PMID:24958932

  2. Response Mixture Modeling: Accounting for Heterogeneity in Item Characteristics across Response Times.

    Science.gov (United States)

    Molenaar, Dylan; de Boeck, Paul

    2018-02-01

    In item response theory modeling of responses and response times, it is commonly assumed that the item responses have the same characteristics across the response times. However, heterogeneity might arise in the data if subjects resort to different response processes when solving the test items. These differences may be within-subject effects, that is, a subject might use a certain process on some of the items and a different process with different item characteristics on the other items. If the probability of using one process over the other process depends on the subject's response time, within-subject heterogeneity of the item characteristics across the response times arises. In this paper, the method of response mixture modeling is presented to account for such heterogeneity. Contrary to traditional mixture modeling where the full response vectors are classified, response mixture modeling involves classification of the individual elements in the response vector. In a simulation study, the response mixture model is shown to be viable in terms of parameter recovery. In addition, the response mixture model is applied to a real dataset to illustrate its use in investigating within-subject heterogeneity in the item characteristics across response times.

  3. Mutagenic hazards of complex polycyclic aromatic hydrocarbon mixtures in contaminated soil

    Energy Technology Data Exchange (ETDEWEB)

    Lemieux, C.L.; Lambert, A.B.; Lundstedt, S.; Tysklind, M.; White, P.A. [Health Canada, Ottawa, ON (Canada). Safe Environment Program

    2008-04-15

    The objective of the present study was to evaluate hazard/risk assessment methods for complex environmental mixtures that involve a targeted, priority chemical approach based on the cumulative hazard/risk of known mixture components or analyses of sufficiently similar mixtures. Ten polycyclic aromatic hydrocarbon (PAH)-contaminated soils were separated into nonpolar and semipolar fractions, and both fractions elicited positive responses on the Salmonella reverse mutation assay. Targeted and nontargeted methods of hazard prediction routinely overestimated mutagenic activities for the nonpolar soil fractions, suggesting nonadditive interactions of PAHs in complex mixtures. This suggests that current risk assessment methods for complex mixtures may provide conservative estimates regarding soils contaminated with priority PAHs alone. Significant underestimations of total risk, however, will be obtained if the soils also contain unidentified PAHs as well as polycyclic aromatic compounds and related compounds that contribute to the total mutagenic activity. Furthermore, estimates of excess lifetime cancer risk associated with the nondietary ingestion of the PAH-contaminated soils studied here indicate that a traditional risk assessment model based on identified priority PAHs and an assumption of additivity generally underestimates the risk associated with the nonpolar soil fractions (in comparison to bioassay-derived risk estimates). Additional cancer risk may be associated with the more polar compounds that also are found at these contaminated sites and that rarely are included in the standard risk assessment methodology.

  4. Construction of a 21-Component Layered Mixture Experiment Design Using a New Mixture Coordinate-Exchange Algorithm

    Energy Technology Data Exchange (ETDEWEB)

    Piepel, Gregory F.; Cooley, Scott K.; Jones, Bradley

    2005-11-01

    This paper describes the solution to a unique and challenging mixture experiment design problem involving: 1) 19 and 21 components for two different parts of the design, 2) many single-component and multi-component constraints, 3) augmentation of existing data, 4) a layered design developed in stages, and 5) a no-candidate-point optimal design approach. The problem involved studying the liquidus temperature of spinel crystals as a function of nuclear waste glass composition. The statistical objective was to develop an experimental design by augmenting existing glasses with new nonradioactive and radioactive glasses chosen to cover the designated nonradioactive and radioactive experimental regions. The existing 144 glasses were expressed as 19-component nonradioactive compositions and then augmented with 40 new nonradioactive glasses. These included 8 glasses on the outer layer of the region, 27 glasses on an inner layer, 2 replicate glasses at the centroid, and one replicate each of three existing glasses. Then, the 144 + 40 = 184 glasses were expressed as 21-component radioactive compositions, and augmented with 5 radioactive glasses. A D-optimal design algorithm was used to select the new outer layer, inner layer, and radioactive glasses. Several statistical software packages can generate D-optimal experimental designs, but nearly all of them require a set of candidate points (e.g., vertices) from which to select design points. The large number of components (19 or 21) and many constraints made it impossible to generate the huge number of vertices and other typical candidate points. JMP was used to select design points without candidate points. JMP uses a coordinate-exchange algorithm modified for mixture experiments, which is discussed and illustrated in the paper.

  5. Perfect posterior simulation for mixture and hidden Marko models

    DEFF Research Database (Denmark)

    Berthelsen, Kasper Klitgaard; Breyer, Laird A.; Roberts, Gareth O.

    2010-01-01

    In this paper we present an application of the read-once coupling from the past algorithm to problems in Bayesian inference for latent statistical models. We describe a method for perfect simulation from the posterior distribution of the unknown mixture weights in a mixture model. Our method...... is extended to a more general mixture problem, where unknown parameters exist for the mixture components, and to a hidden Markov model....

  6. Investigation of a Gamma model for mixture STR samples

    DEFF Research Database (Denmark)

    Christensen, Susanne; Bøttcher, Susanne Gammelgaard; Lauritzen, Steffen L.

    The behaviour of PCR Amplification Kit, when used for mixture STR samples, is investigated. A model based on the Gamma distribution is fitted to the amplifier output for constructed mixtures, and the assumptions of the model is evaluated via residual analysis.......The behaviour of PCR Amplification Kit, when used for mixture STR samples, is investigated. A model based on the Gamma distribution is fitted to the amplifier output for constructed mixtures, and the assumptions of the model is evaluated via residual analysis....

  7. A Convex Hull Formulation for the Design of Optimal Mixtures

    OpenAIRE

    Jonuzaj, S; Adjiman, CS

    2016-01-01

    The design of mixtures plays an important role in improving process and product performance but is challenging because it requires finding the optimal number, identities and compositions of mixture components and using nonlinear property models. To address this, a general modeling framework for mixture design problems is presented. It integrates Generalized Disjunctive Programming (GDP) into Computer-Aided Mixture/blend Design via Hull Reformulation (HR). The design methodology is applied suc...

  8. Liquid class predictor for liquid handling of complex mixtures

    Science.gov (United States)

    Seglke, Brent W [San Ramon, CA; Lekin, Timothy P [Livermore, CA

    2008-12-09

    A method of establishing liquid classes of complex mixtures for liquid handling equipment. The mixtures are composed of components and the equipment has equipment parameters. The first step comprises preparing a response curve for the components. The next step comprises using the response curve to prepare a response indicator for the mixtures. The next step comprises deriving a model that relates the components and the mixtures to establish the liquid classes.

  9. Stability Studies of a Mixture of Paracetamol and Ascorbic Acid ...

    African Journals Online (AJOL)

    Purpose: To determine the effect of the temperature of water used for the preparation of paracetamol and ascorbic acid mixture on its stability, as well as to assess the influence of humidity on the stability of single components and their mixtures. Methods: The stability of the mixtures in aqueous medium was evaluated with ...

  10. Plant relations in mixtures of Trifolium subterraneum cv. Midmar: II ...

    African Journals Online (AJOL)

    Land Equivalent Ratios (LER) were calculated for mixtures of Trifolium subterraneum and Lolium multiflorum in terms of dry matter production and crude protein production. This ratio denotes the yield advantage, if any, of a specific mixture against the pure stands of the different components. The mixture receiving 240 kg N ...

  11. Energy utitlzation by broilers fed different micro-nutrient mixtures ...

    African Journals Online (AJOL)

    Feeding micro-nutrient mixture B improved energy efficiency. It was concluded that the poor performance and the poor energy efficiency of C-fed broilers was as a result of the micronutrient imbalance of the mixture since the mixture is deficient in Zinc and four B-vitamins that affect energy utilization. It also contains ...

  12. Peptide de novo sequencing of mixture tandem mass spectra

    DEFF Research Database (Denmark)

    Gorshkov, Vladimir; Hotta, Stéphanie Yuki Kolbeck; Braga, Thiago Verano

    2016-01-01

    The impact of mixture spectra deconvolution on the performance of four popular de novo sequencing programs was tested using artificially constructed mixture spectra as well as experimental proteomics data. Mixture fragmentation spectra are recognized as a limitation in proteomics because they dec...

  13. Bayesian D-Optimal Choice Designs for Mixtures

    NARCIS (Netherlands)

    A. Ruseckaite (Aiste); P.P. Goos (Peter); D. Fok (Dennis)

    2014-01-01

    markdownabstract__Abstract__ Consumer products and services can often be described as mixtures of ingredients. Examples are the mixture of ingredients in a cocktail and the mixture of different components of waiting time (e.g., in-vehicle and out-of-vehicle travel time) in a transportation

  14. 40 CFR 792.113 - Mixtures of substances with carriers.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 31 2010-07-01 2010-07-01 true Mixtures of substances with carriers... § 792.113 Mixtures of substances with carriers. (a) For each test, control, or reference substance that... the uniformity of the mixture and to determine, periodically, the concentration of the test, control...

  15. 40 CFR 160.113 - Mixtures of substances with carriers.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 23 2010-07-01 2010-07-01 false Mixtures of substances with carriers... Mixtures of substances with carriers. (a) For each test, control, or reference substance that is mixed with... uniformity of the mixture and to determine, periodically, the concentration of the test, control, or...

  16. 21 CFR 58.113 - Mixtures of articles with carriers.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Mixtures of articles with carriers. 58.113 Section... GOOD LABORATORY PRACTICE FOR NONCLINICAL LABORATORY STUDIES Test and Control Articles § 58.113 Mixtures... by appropriate analytical methods shall be conducted: (1) To determine the uniformity of the mixture...

  17. TEMPERATURE INFLUENCE ON PHASE STABILITY OF ETHANOL-GASOLINE MIXTURES

    Directory of Open Access Journals (Sweden)

    Valerian Cerempei

    2011-06-01

    Full Text Available The article investigates phase stability of ethanol-gasoline mixtures depending on their composition, water concentration in ethanol and ethanol-gasoline mixture and temperature. There have been determined the perfect functioning conditions of spark ignition engines fueled with ethanol-gasoline mixtures.

  18. Lessons learned in managing alfalfa-grass mixtures

    Science.gov (United States)

    Grass-alfalfa mixtures have a number of benefits that make them attractive to producers. However, they can be problematic to establish and maintain. Research programs have made progress in understanding the benefits and challenges of alfalfa-grass mixtures. Mixtures may have greater winter survival ...

  19. Low temperature irradiation of vitrifiable mixtures of unsaturated monomers

    International Nuclear Information System (INIS)

    Kaetsu, I.; Ito, A.; Hayashi, K.

    1975-01-01

    A specific mixture containing at least one polymerizable unsaturated monomer which is not vitrifiable by itself can advantageously be polymerized by irradiating the mixture at a temperature not higher than 100 0 C above glass transition temperature of the mixture with an ionizing radiation and/or a light. 12 claims, 6 drawings, figures

  20. Recycling Solvent Mixtures of Ethyl Acetate and Hexanes

    Science.gov (United States)

    Wilkinson, Timothy J.

    1998-12-01

    A method to recycle ethyl acetate-hexanes mixtures from thin-layer or column chromatography experiments is described. The procedure consists of co-distillation of the mixture followed by estimation of the composition by reference to an Rf vs percent composite graph. The mixture is then diluted with the appropriate solvent to achieve the desired composition.

  1. [Pulmonary involvements of sarcoidosis].

    Science.gov (United States)

    Ohmichi, M; Hiraga, Y; Hirasawa, M

    1990-01-01

    We reported about intrathoracic changes and prognosis of 686 patients with sarcoidosis diagnosed in our hospital between 1963 and 1988. We evaluated CT findings in 135 patients with sarcoidosis and found pulmonary involvements in 81. We analyzed CT findings according to the classification by Tuengerthal which classified radiographic findings combining ILO classification of pneumoconiosis and characteristic findings of bronchovascular sheath with sarcoidosis. The CT findings were as follows: small opacities (44 out of 81 cases, 54.3%), large opacities (37 cases, 46.7%). Additional findings were as follows: peribronchial marking (42 cases, 51.9%), contraction (17 cases, 21.0%), pleural involvement (9 cases, 11.1%), bulla (5 cases, 6.2%). The characteristic CT findings of serious sarcoidosis were extasis of bronchus, thickening of the bronchial wall, unclearness of vascular shadow, atelectasis and thickening of pleura. Concerning the prognosis of pulmonary involvement, according to age, patients younger than 30 years old at initial diagnosis were better than those of 30 years and over in terms of disappearance of pulmonary involvements. According to stage, patients of stage I and stage II were better than those of stage III. Among the patients we were able to observe chest X-ray findings during five years according to the character of shadow, ill-defined shadow of small opacities and rounded shadows of large opacities had a higher disappearance rate of pulmonary involvements than irregular shadows of large opacities, atelectasis and contraction.

  2. Modeling phase equilibria for acid gas mixtures using the CPA equation of state. Part II: Binary mixtures with CO2

    DEFF Research Database (Denmark)

    Tsivintzelis, Ioannis; Kontogeorgis, Georgios; Michelsen, Michael Locht

    2011-01-01

    In Part I of this series of articles, the study of H2S mixtures has been presented with CPA. In this study the phase behavior of CO2 containing mixtures is modeled. Binary mixtures with water, alcohols, glycols and hydrocarbons are investigated. Both phase equilibria (vapor–liquid and liquid–liqu...

  3. Some properties of explosive mixtures containing peroxides Part I. Relative performance and detonation of mixtures with triacetone triperoxide.

    Science.gov (United States)

    Zeman, Svatopluk; Trzciński, Waldemar A; Matyás, Robert

    2008-06-15

    This study concerns mixtures of triacetone triperoxide (3,3,6,6,9,9-hexamethyl-1,2,4,5,7,8-hexoxonane, TATP) and ammonium nitrate (AN) with added water (W), as the case may be, and dry mixtures of TATP with urea nitrate (UN). Relative performances (RP) of the mixtures and their individual components, relative to TNT, were determined by means of ballistic mortar. The detonation energies, E0, and detonation velocities, D, were calculated for the mixtures studied by means of the thermodynamic code CHEETAH. Relationships have been found and are discussed between the RP and the E0 values related to unit volume of gaseous products of detonation of these mixtures. These relationships together with those between RP and oxygen balance values of the mixtures studied indicate different types of participation of AN and UN in the explosive decomposition of the respective mixtures. Dry TATP/UN mixtures exhibit lower RP than analogous mixtures TATP/AN containing up to 25% of water. Depending on the water content, the TATP/AN mixtures possess higher detonability values than the ANFO explosives. A semi-logarithmic relationship between the D values and oxygen coefficients has been derived for all the mixtures studied at the charge density of 1000 kg m(-3). Among the mixtures studied, this relationship distinguishes several samples of the type of "tertiary explosives" as well as samples that approach "high explosives" in their performances and detonation velocities.

  4. An equiratio mixture model for non-additive components : a case study for aspartame/acesulfame-K mixtures

    NARCIS (Netherlands)

    Schifferstein, H.N.J.

    1996-01-01

    The Equiratio Mixture Model predicts the psychophysical function for an equiratio mixture type on the basis of the psychophysical functions for the unmixed components. The model reliably estimates the sweetness of mixtures of sugars and sugar-alchohols, but is unable to predict intensity for

  5. Flows and chemical reactions in heterogeneous mixtures

    CERN Document Server

    Prud'homme, Roger

    2014-01-01

    This book - a sequel of previous publications 'Flows and Chemical Reactions' and 'Chemical Reactions in Flows and Homogeneous Mixtures' - is devoted to flows with chemical reactions in heterogeneous environments.  Heterogeneous media in this volume include interfaces and lines. They may be the site of radiation. Each type of flow is the subject of a chapter in this volume. We consider first, in Chapter 1, the question of the generation of environments biphasic individuals: dusty gas, mist, bubble flow.  Chapter 2 is devoted to the study at the mesoscopic scale: particle-fluid exchange of mom

  6. Diffusive flux of energy in binary mixtures

    International Nuclear Information System (INIS)

    Sampaio, R.S.

    1976-04-01

    The diffusive flux of energy j tilde is studied through the reduced diffusive flux of energy K tilde, which obeys equations of the form: sim(delta K tilde/delta grad rho sub(α))= sim(delta K tilde/delta grad theta)=0. By a representation theorem, herein proved, is obtained a general representation for K tilde which is simplified, for the case of binary mixtures, using the principle of objectivity. Some consequences of this representation are discussed such as the symmetry of the partial stresses T 1 tilde and T 2 tilde and the difference between the normal stresses [pt

  7. Thermodynamic properties of mixtures of liquids

    International Nuclear Information System (INIS)

    Benedetti, A.V.; Cilense, M.; Vollet, D.

    1982-01-01

    The molar excess enthalpy (H sup(-E)) of water-ethanol has been measured at 298.15, 306.85, 313.95 and 319.75 K. The mixtures are exothermics at studied temperatures with minimum values of -785, -655, -555 and -490 J. mol -1 respectively, at value of X 2 about 0.16. The other thermodynamics properties have been obtained from experimental data and data from literature. The results are interpreted qualitatively by considering molecular interactions in solution. (Author) [pt

  8. Computing Properties Of Chemical Mixtures At Equilibrium

    Science.gov (United States)

    Mcbride, B. J.; Gordon, S.

    1995-01-01

    Scientists and engineers need data on chemical equilibrium compositions to calculate theoretical thermodynamic properties of chemical systems. Information essential in design and analysis of such equipment as compressors, turbines, nozzles, engines, shock tubes, heat exchangers, and chemical-processing equipment. CET93 is general program that calculates chemical equilibrium compositions and properties of mixtures for any chemical system for which thermodynamic data are available. Includes thermodynamic data for more than 1,300 gaseous and condensed species and thermal-transport data for 151 gases. Written in FORTRAN 77.

  9. Gaussian mixture model of heart rate variability.

    Directory of Open Access Journals (Sweden)

    Tommaso Costa

    Full Text Available Heart rate variability (HRV is an important measure of sympathetic and parasympathetic functions of the autonomic nervous system and a key indicator of cardiovascular condition. This paper proposes a novel method to investigate HRV, namely by modelling it as a linear combination of Gaussians. Results show that three Gaussians are enough to describe the stationary statistics of heart variability and to provide a straightforward interpretation of the HRV power spectrum. Comparisons have been made also with synthetic data generated from different physiologically based models showing the plausibility of the Gaussian mixture parameters.

  10. Pycnonuclear reaction rates for binary ionic mixtures

    Science.gov (United States)

    Ichimaru, S.; Ogata, S.; Van Horn, H. M.

    1992-01-01

    Through a combination of compositional scaling arguments and examinations of Monte Carlo simulation results for the interparticle separations in binary-ionic mixture (BIM) solids, we have derived parameterized expressions for the BIM pycnonuclear rates as generalizations of those in one-component solids obtained previously by Salpeter and Van Horn and by Ogata et al. We have thereby discovered a catalyzing effect of the heavier elements, which enhances the rates of reactions among the lighter elements when the charge ratio exceeds a critical value of approximately 2.3.

  11. Two-microphone Separation of Speech Mixtures

    DEFF Research Database (Denmark)

    2006-01-01

    In this demonstration we show the separation of 3-7 mixed speech sources based on information from two microphones. Separation with background noise is demonstrated too. The algorithms are described in 1] Michael Syskind Pedersen, DeLiang Wang, Jan Larsen and Ulrik Kjems: "Two-microphone Separation...... of Speech Mixtures," 2006, submited for journal publication. See also, [2] Michael Syskind Pedersen, DeLiang Wang, Jan Larsen and Ulrik Kjems: "Overcomplete Blind Source Separation by Combining ICA and Binary Time-Frequency Masking," in proceedings of IEEE International workshop on Machine Learning...

  12. Cardiovascular involvement in myositis

    DEFF Research Database (Denmark)

    Diederichsen, Louise P

    2017-01-01

    PURPOSE OF REVIEW: The purpose of this review is to provide an update on cardiovascular involvement in idiopathic inflammatory myopathy (IIM). Studies from the past 18 months are identified and reviewed. Finally, the clinical impact of these findings is discussed. RECENT FINDINGS: Epidemiological...... on cardiac magnetic resonance (CMR) imaging suggests that CMR should be considered as a potentially viable diagnostic tool to evaluate the possibility of silent myocardial inflammation in IIM with normal routine noninvasive evaluation. SUMMARY: Updated literature on cardiovascular involvement in IIM has...... identified an increased risk for subclinical and clinical cardiovascular disease in these rare inflammatory muscle diseases....

  13. Mixture densities, maximum likelihood, and the EM algorithm

    Science.gov (United States)

    Redner, R. A.; Walker, H. F.

    1982-01-01

    The problem of estimating the parameters which determine a mixture density is reviewed as well as maximum likelihood estimation for it. A particular iterative procedure for numerically approximating maximum likelihood estimates for mixture density problems is considered. This EM algorithm, is a specialization to the mixture density context of a general algorithm of the same name used to approximate maximum likelihood estimates for incomplete data problems. The formulation and theoretical and practical properties of the EM algorithm for mixture densities are discussed focussing in particular on mixtures of densities from exponential families.

  14. Toxicity of combined mixtures of nanoparticles to plants.

    Science.gov (United States)

    Jośko, Izabela; Oleszczuk, Patryk; Skwarek, Ewa

    2017-06-05

    An increasing production and using of nanoproducts results in releasing and dispersing nanoparticles (NPs) in the environment. Being released into various environment components, NPs may interact with numerous pollutants, including other NPs. This research aimed at assessing toxicity of combined binary mixtures of NPs. The study focused on assessing mixtures of NPs believed to be toxic (nano-ZnO+nano-CuO) and nano-ZnO/nano-CuO with the ones that are insignificantly toxic or non-toxic NPs (nano-TiO 2 /nano-Cr 2 O 3 /nano-Fe 2 O 3 ). Toxicity of combined mixtures proved comparable to toxicity of individual mixtures of NPs (the sum of effects triggered by individual types of NPs comprising respective mixtures). Toxicity evaluation was based on two parameters: seed germination and inhibition of root growth with respect to four plant species: Lepidium sativum, Linum utisassimmum, Cucumis sativus and Triticum aestivum. The findings showed combined mixtures of NPs to be significantly less toxic in comparison to individual mixtures, irrespective of their components. Within the scope of concentrations used, greatest differences between the toxicity of mixtures were reported at the 100mgL -1 concentration. Toxicity levels of combined and individual mixtures might have been determined by a lower total concentration of Zn and Cu metals and a greater aggregation of particles in combined mixtures than in individual mixtures. Copyright © 2017 Elsevier B.V. All rights reserved.

  15. Bayesian nonparametric meta-analysis using Polya tree mixture models.

    Science.gov (United States)

    Branscum, Adam J; Hanson, Timothy E

    2008-09-01

    Summary. A common goal in meta-analysis is estimation of a single effect measure using data from several studies that are each designed to address the same scientific inquiry. Because studies are typically conducted in geographically disperse locations, recent developments in the statistical analysis of meta-analytic data involve the use of random effects models that account for study-to-study variability attributable to differences in environments, demographics, genetics, and other sources that lead to heterogeneity in populations. Stemming from asymptotic theory, study-specific summary statistics are modeled according to normal distributions with means representing latent true effect measures. A parametric approach subsequently models these latent measures using a normal distribution, which is strictly a convenient modeling assumption absent of theoretical justification. To eliminate the influence of overly restrictive parametric models on inferences, we consider a broader class of random effects distributions. We develop a novel hierarchical Bayesian nonparametric Polya tree mixture (PTM) model. We present methodology for testing the PTM versus a normal random effects model. These methods provide researchers a straightforward approach for conducting a sensitivity analysis of the normality assumption for random effects. An application involving meta-analysis of epidemiologic studies designed to characterize the association between alcohol consumption and breast cancer is presented, which together with results from simulated data highlight the performance of PTMs in the presence of nonnormality of effect measures in the source population.

  16. mixtools: An R Package for Analyzing Mixture Models

    Directory of Open Access Journals (Sweden)

    Tatiana Benaglia

    2009-10-01

    Full Text Available The mixtools package for R provides a set of functions for analyzing a variety of finite mixture models. These functions include both traditional methods, such as EM algorithms for univariate and multivariate normal mixtures, and newer methods that reflect some recent research in finite mixture models. In the latter category, mixtools provides algorithms for estimating parameters in a wide range of different mixture-of-regression contexts, in multinomial mixtures such as those arising from discretizing continuous multivariate data, in nonparametric situations where the multivariate component densities are completely unspecified, and in semiparametric situations such as a univariate location mixture of symmetric but otherwise unspecified densities. Many of the algorithms of the mixtools package are EM algorithms or are based on EM-like ideas, so this article includes an overview of EM algorithms for finite mixture models.

  17. Health and environmental effects of complex chemical mixtures: proceedings

    Energy Technology Data Exchange (ETDEWEB)

    1985-01-01

    The Office of Health and Environmental Research (OHER) of the Department of Energy supports a broad long-term research program on human health and environmental effects from potential exposure to energy-related complex chemical mixtures. The program seeks basic mechanistic data on the effects of complex mixtures at the cellular, molecular, and whole animal levels to aid in predicting human health effects and seeks ecological data on biological and physical transformations in the mixtures, concentrations of the mixtures in various compartments of the environment, and potential routes for human exposure to these mixtures (e.g., food chain). On June 17-18, 1985, OHER held its First Annual Technical Meeting on the Complex Chemical Mixtures Program in Chicago, IL. The primary purpose of the meeting was to enable principal investigators to report the research status and accomplishments of ongoing complex chemical mixture studies supported by OHER. To help focus future research directions round table discussions were conducted.

  18. Public and patient involvement.

    Science.gov (United States)

    2003-09-01

    Public and patient involvement in the NHS is one of the new Department of Health mantras, and one source of useful information you can pass on to service users is the Consumers in NHS Research website at www.conres.co.uk/dat.htm.

  19. Job Involvement of Teachers.

    Science.gov (United States)

    Knoop, Robert

    This study investigated the relationship between job involvement and three sets of variables: nine personal (age, sex, marital status, education, overall experience, nonteaching experience, present school experience, income, and locus of control), three structural (size of school, location of school, and hierarchical position), and eight job…

  20. Who Involves Whom?

    Science.gov (United States)

    Ward, Clifford

    1979-01-01

    The author reviews the development of a parents' group at the Bradford Grange School (Manchester, United Kingdom) for ESN (educationally subnormal) children. Problems with the initial parents' group are pointed out, successful approaches are considered, and the importance of parent involvement is stressed. (SBH)

  1. Involving Divorced Parents.

    Science.gov (United States)

    Tarriff, Harold M.; Levine, Valerie

    1993-01-01

    In divorced families, the noncustodial parent is usually as important to the child as the residential parent. Schools should avoid actions that cause parental conflict, place one parent in a sole decision-making role, or deny a parent's access to information or involvement. School responsibilities governing routine correspondence, cyclical and…

  2. PATTERNS AND FACTORS INVOLVED

    African Journals Online (AJOL)

    Between 1*' of July 1996 and 30'h of June 2000 a total of 3583 patients were registered at the accident and emergency unit of Nnamdi. Azikiwe ... The case files of these were reviewed with a view to ascertaining the causes and factors involved in the deaths of these patients. The .... H.I.V/AIDS related complications 23 6.8.

  3. DDT in methane-air mixtures

    Science.gov (United States)

    Kuznetsov, M.; Ciccarelli, G.; Dorofeev, S.; Alekseev, V.; Yankin, Yu.; Kim, T. H.

    Experimental results from a study on the critical condition for deflagration-to-detonation transition (DDT) in methane-air mixtures are presented. Experiments were carried out at 293 K and 1 atm using methane-air mixtures with methane concentrations ranging from 5.5 to 17% vol. The tests were performed in detonation tubes with inner-diameters of 174 mm and 520 mm. Detonation cell widths λ were determined in the tests for a range of methane concentrations. The results of DDT tests indicate that for a tube cross-sectional area blockage ratio (BR) of 0.3 the critical condition for DDT can be characterized by the d/λ = 1 criterion. However, for a BR = 0.6 the critical value d/λ was significantly higher. The data also show that the critical condition for DDT can be described by L/λ = 7, where L is the characteristic length-scale of the channel volume between orifice plates. This length-scale is defined by a grouping of the orifice plate dimensions (inner and outer-diameter) and plate spacing.

  4. Developmental Exposure to an Environmental PCB Mixture ...

    Science.gov (United States)

    Developmental PCB exposure impairs hearing and induces brainstem audiogenic seizures in adult offspring. The degree to which this enhanced susceptibility to seizure is manifest in other brain regions has not been examined. Thus, electrical kindling of the amygdala was used to evaluate the effect of developmental exposure to an environmentally relevant PCB mixture on seizure susceptibility in the rat. Female Long-Evans rats were dosed orally with 0 or 6 mg/kg/day of the PCB mixture dissolved in corn oil vehicle during the perinatal period. On postnatal day (PND) 21, pups were weaned, and two males from each litter were randomly selected for the kindling study. As adults, the male rats were implanted bilaterally with electrodes in the basolateral amygdala. For each animal, afterdischarge (AD) thresholds in the amygdala were determined on the first day of testing followed by once daily stimulation at a standard 200 µA stimulus intensity until three stage 5 generalized seizures (GS) ensued. Developmental PCB exposure did not affect the AD threshold or total cumulative AD duration, but PCB exposure did increase the latency to behavioral manifestations of seizure propagation. PCB exposed animals required significantly more stimulations to reach stage 2 seizures compared to control animals, indicating an attenuated focal (amygdala) excitability. A delay in kindling progression from a focally stimulated limbic site stands in contrast to our previous finding of increase

  5. Rutting performance of cold bituminous emulsion mixtures

    Science.gov (United States)

    Arshad, Ahmad Kamil; Ali, Noor Azilatom; Shaffie, Ekarizan; Hashim, Wardati; Rahman, Zanariah Abd

    2017-10-01

    Cold Bituminous Emulsion Mixture (CBEM) is an environmentally friendly alternative to hot mix asphalt (HMA) for road surfacing, due to its low energy requirements. However, CBEM has generally been perceived to be less superior in performance, compared to HMA. This paper details a laboratory study on the rutting performance of CBEM. The main objective of this study is to determine the Marshall properties of CBEM and to evaluate the rutting performance. The effect of cement in CBEM was also evaluated in this study. The specimens were prepared using Marshall Mix Design Method and rutting performance was evaluated using the Asphalt Pavement Analyzer (APA). Marshall Properties were analysed to confirm compliance with the PWD Malaysia's specification requirements. The rutting performance for specimens with cement was also found to perform better than specimens without cement. It can be concluded that Cold Bituminous Emulsion Mixtures (CBEM) with cement is a viable alternative to Hot Mix Asphalt (HMA) as their Marshall Properties and performance obtained from this study meets the requirements of the specifications. It is recommended that further study be conducted on CBEM for other performance criteria such as moisture susceptibility and fatigue.

  6. Thermodynamics of organic mixtures containing amines

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez, Juan Antonio [G.E.T.E.F. Dpto Termodinamica y Fisica Aplicada, Facultad de Ciencias, Universidad de Valladolid, Valladolid 47071 (Spain)]. E-mail: jagl@termo.uva.es; Mozo, Ismael [G.E.T.E.F. Dpto Termodinamica y Fisica Aplicada, Facultad de Ciencias, Universidad de Valladolid, Valladolid 47071 (Spain); Fuente, Isaias Garcia de la [G.E.T.E.F. Dpto Termodinamica y Fisica Aplicada, Facultad de Ciencias, Universidad de Valladolid, Valladolid 47071 (Spain); Cobos, Jose Carlos [G.E.T.E.F. Dpto Termodinamica y Fisica Aplicada, Facultad de Ciencias, Universidad de Valladolid, Valladolid 47071 (Spain)

    2006-02-01

    Binary mixtures containing pyridine (PY), or 2-methylpyridine (2MPY) or 3-methylpyridine (3MPY) or 4-methylpyridine (4MPY) and an organic solvent as benzene, toluene, alkane, or 1-alkanol are investigated in the framework of DISQUAC. The corresponding interaction parameters are reported. The model describes accurately a whole set of thermodynamic properties: vapor-liquid equilibria (VLE), liquid-liquid equilibria (LLE), solid-liquid equilibria (SLE), molar excess Gibbs energies (G{sup E}), molar excess enthalpies (H{sup E}), molar excess heat capacities at constant pressure (C{sub P}{sup E}) and the concentration-concentration structure factor (S{sub CC}(0)). It is remarkable that DISQUAC correctly predicts the W-shaped curve of the C{sub P}{sup E} of the pyridine + n-hexadecane system. The model can be applied successfully to mixtures with strong positive or negative deviations from the Raoult's law. DISQUAC improves the theoretical results from UNIFAC (Dortmund version). The replacement of pyridine by a methylpyridine leads to a weakening of the amine-amine interactions, ascribed to the steric effect caused by the methyl group attached to the aromatic ring. This explains that for a given solvent (alkane, 1-alkanol) H{sup E}(pyridine)>H{sup E}(methylpyridine)

  7. Acid resistance of sewer pipe concrete mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Alexander, M. G.; Fourie, C. [Cape Town Univ., Dept. of Civil Engineering (South Africa)

    2000-07-01

    Using hydrochloric acid in a test method developed at the University of Cape Town, six different sets of concrete materials were measured for acid resistance. One of the six mixtures was a standard mix used for the preparation of sewer pipes by the roller suspension method; the other five were variations of the standard mix, modified by the partial replacement of the standard cement with slag, fly ash, condensed silica fume or metakaolin. In one test mixture, normal portland cement was replaced by a calcium aluminate cement. At 28 days the physical properties of concrete with admixtures of silica fume and metakaolin were superior to the other concretes, although the acid resistance of metakaolin concrete showed no improvement despite otherwise superior quality. The concrete containing condensed silica fume showed marked improvement in acid resistance It showed a lower percentage of mass loss and hydrogen ion consumption than other concretes. This concrete also compacted well, indicating its high suitability for the production of sewer pipes with the roller suspension method. Slag and fly ash concretes did not gain strength rapidly enough and calcium aluminate also showed limited capacity to protect the sewer pipes from bacterial attack, despite its reputed toxicity to the Thiobacillus bacteria, which is the principal agent of acid attack in sewer pipes. 8 refs., 5 tabs., 3 figs.

  8. Thermodynamics of organic mixtures containing amines

    International Nuclear Information System (INIS)

    Gonzalez, Juan Antonio; Mozo, Ismael; Fuente, Isaias Garcia de la; Cobos, Jose Carlos

    2006-01-01

    Binary mixtures containing pyridine (PY), or 2-methylpyridine (2MPY) or 3-methylpyridine (3MPY) or 4-methylpyridine (4MPY) and an organic solvent as benzene, toluene, alkane, or 1-alkanol are investigated in the framework of DISQUAC. The corresponding interaction parameters are reported. The model describes accurately a whole set of thermodynamic properties: vapor-liquid equilibria (VLE), liquid-liquid equilibria (LLE), solid-liquid equilibria (SLE), molar excess Gibbs energies (G E ), molar excess enthalpies (H E ), molar excess heat capacities at constant pressure (C P E ) and the concentration-concentration structure factor (S CC (0)). It is remarkable that DISQUAC correctly predicts the W-shaped curve of the C P E of the pyridine + n-hexadecane system. The model can be applied successfully to mixtures with strong positive or negative deviations from the Raoult's law. DISQUAC improves the theoretical results from UNIFAC (Dortmund version). The replacement of pyridine by a methylpyridine leads to a weakening of the amine-amine interactions, ascribed to the steric effect caused by the methyl group attached to the aromatic ring. This explains that for a given solvent (alkane, 1-alkanol) H E (pyridine)>H E (methylpyridine)

  9. Equilibrium study for ternary mixtures of biodiesel

    Science.gov (United States)

    Doungsri, S.; Sookkumnerd, T.; Wongkoblap, A.; Nuchitprasittichai, A.

    2017-11-01

    The liquid-liquid equilibrium (LLE) data for the ternary mixtures of methanol + fatty acid methyl ester (FAME) + palm oil and FAME + palm oil + glycerol at various temperatures from 35 to 55°C, the tie lines and binodial curves were also investigated and plotted in the equilibrium curve. The experimental results showed that the binodial curves of methanol + FAME + palm oil depended significantly with temperature while the binodial curves of FAME + palm oil + glycerol illustrated insignificant change with temperatures. The interaction parameters between liquid pair obtained for NRTL (Nonrandom Two-Liquid) and UNIQUAC (Universal Quasi-Chemical Theory) models from the experimental data were also investigated. It was found that the correlated parameters of UNIQUAC model for system of FAME + palm oil + glycerol, denoted as a13 and a31, were 580.42K and -123.69K, respectively, while those for system of methanol + FAME + palm oil, denoted as a42 and a24, were 71.48 K and 965.57K, respectively. The ternary LLE data reported here would be beneficial for engineers and scientists to use for prediction of yield and purity of biodiesel for the production. The UNIQUAC model agreed well with the experimental data of ternary mixtures of biodiesel.

  10. Thermal neutron diffusion parameters in homogeneous mixtures

    International Nuclear Information System (INIS)

    Drozdowicz, K.; Krynicka, E.

    1995-01-01

    A physical background is presented for a computer program which calculates the thermal neutron diffusion parameters for homogeneous mixtures of any compounds. The macroscopic absorption, scattering and transport cross section of the mixture are defined which are generally function of the incident neutron energy. The energy-averaged neutron parameters are available when these energy dependences and the thermal neutron energy distribution are assumed. Then the averaged diffusion coefficient and the pulsed thermal neutron parameters (the absorption rare and the diffusion constant) are also defined. The absorption cross section is described by the 1/v law and deviations from this behaviour are considered. The scattering cross section can be assumed as being almost constant in the thermal neutron region (which results from the free gas model). Serious deviations are observed for hydrogen atoms bound in molecules and a special study in the paper is devoted to this problem. A certain effective scattering cross section is found in this case on a base of individual exact data for a few hydrogenous media. Approximations assumed for the average cosine of the scattering angle are also discussed. The macroscopic parameters calculated are averaged over the Maxwellian energy distribution for the thermal neutron flux. An information on the input data for the computer program is included. (author). 10 refs, 4 figs, 5 tabs

  11. Use of Adhesion Promoters in Asphalt Mixtures

    Directory of Open Access Journals (Sweden)

    Cihlářová Denisa

    2018-03-01

    Full Text Available The purpose of asphalt binder as a significant binder in road constructions is to permanently bind aggregates of different compositions and grain sizes. The asphalt binder itself does not have suitable adhesiveness, so after a period of time, bare grains can appear. This results in a gradual separation of the grains from an asphalt layer and the presence of potholes in a pavement. Adhesion promoters or adhesive agents are important and proven promoters in practice. They are substances mainly based on the fatty acids of polyamides which should increase the reliability of the asphalt’s binder adhesion to the aggregates, thus increasing the lifetime period of the asphalt mixture as well as its resistance to mechanical strain. The amount of a promoter or agent added to the asphalt mixture is negligible and constitutes about 0.3% of the asphalt’s binder weight. Nevertheless, even this quantity significantly increases the adhesive qualities of an asphalt binder. The article was created in cooperatation with the Slovak University of Technology, in Bratislava, Slovakia, and focuses on proving the new AD2 adhesive additive and comparing it with the Addibit and Wetfix BE promoters used on aggregates from the Skuteč - Litická and Bystřec quarries.

  12. Honeybees learn odour mixtures via a selection of key odorants.

    Directory of Open Access Journals (Sweden)

    Judith Reinhard

    2010-02-01

    Full Text Available The honeybee has to detect, process and learn numerous complex odours from her natural environment on a daily basis. Most of these odours are floral scents, which are mixtures of dozens of different odorants. To date, it is still unclear how the bee brain unravels the complex information contained in scent mixtures.This study investigates learning of complex odour mixtures in honeybees using a simple olfactory conditioning procedure, the Proboscis-Extension-Reflex (PER paradigm. Restrained honeybees were trained to three scent mixtures composed of 14 floral odorants each, and then tested with the individual odorants of each mixture. Bees did not respond to all odorants of a mixture equally: They responded well to a selection of key odorants, which were unique for each of the three scent mixtures. Bees showed less or very little response to the other odorants of the mixtures. The bees' response to mixtures composed of only the key odorants was as good as to the original mixtures of 14 odorants. A mixture composed of the other, non-key-odorants elicited a significantly lower response. Neither an odorant's volatility or molecular structure, nor learning efficiencies for individual odorants affected whether an odorant became a key odorant for a particular mixture. Odorant concentration had a positive effect, with odorants at high concentration likely to become key odorants.Our study suggests that the brain processes complex scent mixtures by predominantly learning information from selected key odorants. Our observations on key odorant learning lend significant support to previous work on olfactory learning and mixture processing in honeybees.

  13. Honeybees Learn Odour Mixtures via a Selection of Key Odorants

    Science.gov (United States)

    Reinhard, Judith; Sinclair, Michael; Srinivasan, Mandyam V.; Claudianos, Charles

    2010-01-01

    Background The honeybee has to detect, process and learn numerous complex odours from her natural environment on a daily basis. Most of these odours are floral scents, which are mixtures of dozens of different odorants. To date, it is still unclear how the bee brain unravels the complex information contained in scent mixtures. Methodology/Principal Findings This study investigates learning of complex odour mixtures in honeybees using a simple olfactory conditioning procedure, the Proboscis-Extension-Reflex (PER) paradigm. Restrained honeybees were trained to three scent mixtures composed of 14 floral odorants each, and then tested with the individual odorants of each mixture. Bees did not respond to all odorants of a mixture equally: They responded well to a selection of key odorants, which were unique for each of the three scent mixtures. Bees showed less or very little response to the other odorants of the mixtures. The bees' response to mixtures composed of only the key odorants was as good as to the original mixtures of 14 odorants. A mixture composed of the other, non-key-odorants elicited a significantly lower response. Neither an odorant's volatility or molecular structure, nor learning efficiencies for individual odorants affected whether an odorant became a key odorant for a particular mixture. Odorant concentration had a positive effect, with odorants at high concentration likely to become key odorants. Conclusions/Significance Our study suggests that the brain processes complex scent mixtures by predominantly learning information from selected key odorants. Our observations on key odorant learning lend significant support to previous work on olfactory learning and mixture processing in honeybees. PMID:20161714

  14. A numerical study of laminar flames propagating in stratified mixtures

    Science.gov (United States)

    Zhang, Jiacheng

    Numerical simulations are carried out to study the structure and speed of laminar flames propagating in compositionally and thermally stratified fuel-air mixtures. The study is motivated by the need to understand the physics of flame propagation in stratified-charge engines and model it. The specific question of interest in this work is: how does the structure and speed of the flame in the stratified mixture differ from that of the flame in a corresponding homogeneous mixture at the same equivalence ratio, temperature, and pressure? The studies are carried out in hydrogen-air, methane-air, and n-heptane-air mixtures. A 30-species 184-step skeletal mechanism is employed for methane oxidation, a 9-species 21-step mechanism for hydrogen oxidation, and a 37-species 56-step skeletal mechanism for n-heptane oxidation. Flame speed and structure are compared with corresponding values for homogeneous mixtures. For compositionally stratified mixtures, as shown in prior experimental work, the numerical results suggest that when the flame propagates from a richer mixture to a leaner mixture, the flame speed is faster than the corresponding speed in the homogeneous mixture. This is caused by enhanced diffusion of heat and species from the richer mixture to the leaner mixture. In fact, the effects become more pronounced in leaner mixtures. Not surprisingly, the stratification gradient influences the results with shallower gradients showing less effect. The controlling role that diffusion plays is further assessed and confirmed by studying the effect of a unity Lewis number assumption in the hydrogen/air mixtures. Furthermore, the effect of stratification becomes less important when using methane or n-heptane as fuel. The laminar flame speed in a thermally stratified mixture is similar to the laminar flame speed in homogeneous mixture at corresponding unburned temperature. Theoretical analysis is performed and the ratio of extra thermal diffusion rate to flame heat release rate

  15. Gas-particle partitioning of semivolatile organic compounds (SOCs) on mixtures of aerosols in a smog chamber.

    Science.gov (United States)

    Chandramouli, Bharadwaj; Jang, Myoseon; Kamens, Richard M

    2003-09-15

    The partitioning behavior of a set of diverse SOCs on two and three component mixtures of aerosols from different sources was studied using smog chamber experimental data. A set of SOCs of different compound types was introduced into a system containing a mixture of aerosols from two or more sources. Gas and particle samples were taken using a filter-filter-denuder sampling system, and a partitioning coefficient Kp was estimated using Kp = Cp/(CgTSP). Particle size distributions were measured using a differential mobility analyzer and a light scattering detector. Gas and particle samples were analyzed using GCMS. The aerosol composition in the chamber was tracked chemically using a combination of signature compounds and the organic matter mass fraction (f(om)) of the individual aerosol sources. The physical nature of the aerosol mixture in the chamber was determined using particle size distributions, and an aggregate Kp was estimated from theoretically calculated Kp on the individual sources. Model fits for Kp showed that when the mixture involved primary sources of aerosol, the aggregate Kp of the mixture could be successfully modeled as an external mixture of the Kp on the individual aerosols. There were significant differences observed for some SOCs between modeling the system as an external and as an internal mixture. However, when one of the aerosol sources was secondary, the aggregate model Kp required incorporation of the secondary aerosol products on the preexisting aerosol for adequate model fits. Modeling such a system as an external mixture grossly overpredicted the Kp of alkanes in the mixture. Indirect evidence of heterogeneous, acid-catalyzed reactions in the particle phase was also seen, leading to a significant increase in the polarity of the resulting aerosol mix and a resulting decrease in the observed Kp of alkanes in the chamber. The model was partly consistent with this decrease but could not completely explain the reduction in Kp because of

  16. Efficacy of fungal decolorization of a mixture of dyes belonging to different classes.

    Science.gov (United States)

    Przystas, Wioletta; Zablocka-Godlewska, Ewa; Grabinska-Sota, Elzbieta

    2015-06-01

    Dyes are the most difficult constituents to remove by conventional biological wastewater treatment. Colored wastewater is mainly eliminated by physical and chemical procedures, which are very expensive and have drawbacks. Therefore, the advantage of using biological processes, such as the biotransformation of dyes, is that they may lead to complete mineralization or formation of less toxic products. To prove the possibility of using fungal processes for decolorization and other applications, the analysis of the toxicity of the processes' products is required. The decolorization of the mixture of two dyes from different classes - triphenylmethane brilliant green and azo Evans blue (GB - total concentration 0.08 g/L, proportion 1:1 w/w) - by Pleurotus ostreatus (BWPH and MB), Gloeophyllum odoratum (DCa), RWP17 (Polyporus picipes) and Fusarium oxysporum (G1) was studied. Zootoxicity (Daphnia magna) and phytotoxicity (Lemna minor) changes were estimated at the end of the experiment. The mixture of dyes was significantly removed by all the strains that were tested with 96 h of experimental time. However, differences among strains from the same species (P. ostreatus) were noted. Shaking improved the efficacy and rate of the dye removal. In static samples, the removal of the mixture reached more than 51.9% and in shaken samples, more than 79.2%. Tests using the dead biomass of the fungi only adsorbed up to 37% of the dye mixture (strain BWPH), which suggests that the process with the living biomass involves the biotransformation of the dyes. The best results were reached for the MB strain, which removed 90% of the tested mixture under shaking conditions. Regardless of the efficacy of the dye removal, toxicity decreased from class V to class III in tests with D. magna. Tests with L. minor control samples were classified as class IV, and samples with certain strains were non-toxic. The highest phytotoxicity decrease was noted in shaken samples where the elimination of dye

  17. Efficacy of fungal decolorization of a mixture of dyes belonging to different classes

    Directory of Open Access Journals (Sweden)

    Wioletta Przystas

    2015-06-01

    Full Text Available Dyes are the most difficult constituents to remove by conventional biological wastewater treatment. Colored wastewater is mainly eliminated by physical and chemical procedures, which are very expensive and have drawbacks. Therefore, the advantage of using biological processes, such as the biotransformation of dyes, is that they may lead to complete mineralization or formation of less toxic products. To prove the possibility of using fungal processes for decolorization and other applications, the analysis of the toxicity of the processes' products is required. The decolorization of the mixture of two dyes from different classes - triphenylmethane brilliant green and azo Evans blue (GB - total concentration 0.08 g/L, proportion 1:1 w/w - by Pleurotus ostreatus (BWPH and MB, Gloeophyllum odoratum (DCa, RWP17 (Polyporus picipes and Fusarium oxysporum (G1 was studied. Zootoxicity (Daphnia magna and phytotoxicity (Lemna minor changes were estimated at the end of the experiment. The mixture of dyes was significantly removed by all the strains that were tested with 96 h of experimental time. However, differences among strains from the same species (P. ostreatus were noted. Shaking improved the efficacy and rate of the dye removal. In static samples, the removal of the mixture reached more than 51.9% and in shaken samples, more than 79.2%. Tests using the dead biomass of the fungi only adsorbed up to 37% of the dye mixture (strain BWPH, which suggests that the process with the living biomass involves the biotransformation of the dyes. The best results were reached for the MB strain, which removed 90% of the tested mixture under shaking conditions. Regardless of the efficacy of the dye removal, toxicity decreased from class V to class III in tests with D. magna. Tests with L. minor control samples were classified as class IV, and samples with certain strains were non-toxic. The highest phytotoxicity decrease was noted in shaken samples where the

  18. Concrete pavement mixture design and analysis (MDA) : effect of aggregate systems on concrete mixture properties.

    Science.gov (United States)

    2012-07-01

    For years, specifications have focused on the water to cement ratio (w/cm) and strength of concrete, despite the majority of the volume : of a concrete mixture consisting of aggregate. An aggregate distribution of roughly 60% coarse aggregate and 40%...

  19. Differential gene expression pattern in human mammary epithelial cells induced by realistic organochlorine mixtures described in healthy women and in women diagnosed with breast cancer.

    Science.gov (United States)

    Rivero, Javier; Henríquez-Hernández, Luis Alberto; Luzardo, Octavio P; Pestano, José; Zumbado, Manuel; Boada, Luis D; Valerón, Pilar F

    2016-03-30

    Organochlorine pesticides (OCs) have been associated with breast cancer development and progression, but the mechanisms underlying this phenomenon are not well known. In this work, we evaluated the effects exerted on normal human mammary epithelial cells (HMEC) by the OC mixtures most frequently detected in healthy women (H-mixture) and in women diagnosed with breast cancer (BC-mixture), as identified in a previous case-control study developed in Spain. Cytotoxicity and gene expression profile of human kinases (n=68) and non-kinases (n=26) were tested at concentrations similar to those described in the serum of those cases and controls. Although both mixtures caused a down-regulation of genes involved in the ATP binding process, our results clearly indicate that both mixtures may exert a very different effect on the gene expression profile of HMEC. Thus, while BC-mixture up-regulated the expression of oncogenes associated to breast cancer (GFRA1 and BHLHB8), the H-mixture down-regulated the expression of tumor suppressor genes (EPHA4 and EPHB2). Our results indicate that the composition of the OC mixture could play a role in the initiation processes of breast cancer. In addition, the present results suggest that subtle changes in the composition and levels of pollutants involved in environmentally relevant mixtures might induce very different biological effects, which explain, at least partially, why some mixtures seem to be more carcinogenic than others. Nonetheless, our findings confirm that environmentally relevant pollutants may modulate the expression of genes closely related to carcinogenic processes in the breast, reinforcing the role exerted by environment in the regulation of genes involved in breast carcinogenesis. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  20. Microorganisms involved in MIC

    Energy Technology Data Exchange (ETDEWEB)

    Sorensen, K. [Danish Technological Institute (Denmark)

    2011-07-01

    Microbiologically influenced corrosion (MIC) is a widespread problem that is difficult to detect and assess because of its complex mechanism. This paper presents the involvement of microorganisms in MIC. Some of the mechanisms that cause MIC include hydrogen consumption, production of acids, anode-cathode formation and electron shuttling. A classic bio-corrosive microorganism in the oil and gas industry is sulphate-reducing prokaryotes (SRP). Methanogens also increase corrosion rates in metals. Some of the phylogenetic orders detected while studying SRP and methanogens are archaeoglobales, clostridiales, methanosarcinales and methanothermococcus. There were some implications, such as growth of SRP not being correlated with growth of methanogens; methanogens were included in MIC risk assessment. A few examples are used to display how microorganisms are involved in topside corrosion and microbial community in producing wells. From the study, it can be concluded that, MIC risk assessment includes system data and empirical knowledge of the distribution and number of microorganisms in the system.

  1. Involved Node Radiation Therapy

    DEFF Research Database (Denmark)

    Maraldo, Maja V; Aznar, Marianne C; Vogelius, Ivan R

    2012-01-01

    PURPOSE: The involved node radiation therapy (INRT) strategy was introduced for patients with Hodgkin lymphoma (HL) to reduce the risk of late effects. With INRT, only the originally involved lymph nodes are irradiated. We present treatment outcome in a retrospective analysis using this strategy...... to 36 Gy). Patients attended regular follow-up visits until 5 years after therapy. RESULTS: The 4-year freedom from disease progression was 96.4% (95% confidence interval: 92.4%-100.4%), median follow-up of 50 months (range: 4-71 months). Three relapses occurred: 2 within the previous radiation field......, and 1 in a previously uninvolved region. The 4-year overall survival was 94% (95% confidence interval: 88.8%-99.1%), median follow-up of 58 months (range: 4-91 months). Early radiation therapy toxicity was limited to grade 1 (23.4%) and grade 2 (13.8%). During follow-up, 8 patients died, none from HL, 7...

  2. Involvement through photography.

    Science.gov (United States)

    Takai, J

    2016-12-01

    As a photographer living in Tokyo, I have been visiting Suetsugi village regularly to take photographs and show the printed photographs to the residents. What is the role of photography? What does it mean to be involved in the life of Suetsugi through photography? This article discusses some of the answers to these questions 5 years after the accident at Fukushima Daiichi nuclear power plant.

  3. Colonic infusions of short-chain fatty acid mixtures promote energy metabolism in overweight/obese men

    DEFF Research Database (Denmark)

    Canfora, Emanuel E; van der Beek, Christina M; Jocken, Johan W E

    2017-01-01

    Short-chain fatty acids (SCFA), formed by microbial fermentation, are believed to be involved in the aetiology of obesity and diabetes. This study investigated the effects of colonic administration of physiologically relevant SCFA mixtures on human substrate and energy metabolism. In this randomi......Short-chain fatty acids (SCFA), formed by microbial fermentation, are believed to be involved in the aetiology of obesity and diabetes. This study investigated the effects of colonic administration of physiologically relevant SCFA mixtures on human substrate and energy metabolism....... In this randomized, double-blind, crossover study, twelve normoglycaemic men (BMI 25-35 kg/m(2)) underwent four investigational days, during which SCFA mixtures (200 mmol/L) high in either acetate (HA), propionate (HP), butyrate (HB) or placebo (PLA) were rectally administered during fasting and postprandial...

  4. Mechanical and economical impacts of adding polymers into asphalt mixtures

    Directory of Open Access Journals (Sweden)

    Souliman Mena

    2017-01-01

    Full Text Available Load associated fatigue cracking is one of the major distress types occurring in flexible pavements. Flexural bending beam fatigue laboratory test has been used for several decades and is considered an integral part of the Superpave advanced characterization procedure. One of the most significant solutions to sustain the fatigue life for an asphaltic mixture is to add sustainable materials such as polymers to the asphalt mixture. A laboratory testing program was performed on two gap-graded mixtures: unmodified and polymer-modified asphalt mixtures. Strain controlled fatigue tests were conducted according to the AASHTO T321 procedure. The results from the beam fatigue tests indicated that the polymer-modified gap graded mixture would have much longer fatigue life compared to the reference (unmodified mixture. In addition, a mechanistic analysis using 3D-Move software coupled with a cost-effectiveness analysis study based on the fatigue performance on the three mixtures were performed. Overall, the analysis showed that the polymer-modified asphalt mixture exhibited significantly higher cost-effectiveness compared to unmodified HMA mixture. Although polymer-modification increases the cost of the material, the analysis showed that it is more cost effective than the unmodified mixture.

  5. A mechanistic model for rational design of optimal cellulase mixtures.

    Science.gov (United States)

    Levine, Seth E; Fox, Jerome M; Clark, Douglas S; Blanch, Harvey W

    2011-11-01

    A model-based framework is described that permits the optimal composition of cellulase enzyme mixtures to be found for lignocellulose hydrolysis. The rates of hydrolysis are shown to be dependent on the nature of the substrate. For bacterial microcrystalline cellulose (BMCC) hydrolyzed by a ternary cellulase mixture of EG2, CBHI, and CBHII, the optimal predicted mixture was 1:0:1 EG2:CBHI:CBHII at 24 h and 1:1:0 at 72 h, at loadings of 10 mg enzyme per g substrate. The model was validated with measurements of soluble cello-oligosaccharide production from BMCC during both single enzyme and mixed enzyme hydrolysis. Three-dimensional diagrams illustrating cellulose conversion were developed for mixtures of EG2, CBHI, CBHII acting on BMCC and predicted for other substrates with a range of substrate properties. Model predictions agreed well with experimental values of conversion after 24 h for a variety of enzyme mixtures. The predicted mixture performances for substrates with varying properties demonstrated the effects of initial degree of polymerization (DP) and surface area on the performance of cellulase mixtures. For substrates with a higher initial DP, endoglucanase enzymes accounted for a larger fraction of the optimal mixture. Substrates with low surface areas showed significantly reduced hydrolysis rates regardless of mixture composition. These insights, along with the quantitative predictions, demonstrate the utility of this model-based framework for optimizing cellulase mixtures. Copyright © 2011 Wiley Periodicals, Inc.

  6. Estimation of Effect Size from a Series of Experiments Involving Paired Comparisons.

    Science.gov (United States)

    Gibbons, Robert D.; And Others

    1993-01-01

    A distribution theory is derived for a G. V. Glass-type (1976) estimator of effect size from studies involving paired comparisons. The possibility of combining effect sizes from studies involving a mixture of related and unrelated samples is also explored. Resulting estimates are illustrated using data from previous psychiatric research. (SLD)

  7. Urea and deuterium mixtures at high pressures

    Energy Technology Data Exchange (ETDEWEB)

    Donnelly, M., E-mail: m.donnelly-2@sms.ed.ac.uk; Husband, R. J.; Frantzana, A. D.; Loveday, J. S. [Centre for Science at Extreme Conditions and School of Physics and Astronomy, The University of Edinburgh, Erskine Williamson Building, Peter Guthrie Tait Road, The King’s Buildings, Edinburgh EH9 3FD (United Kingdom); Bull, C. L. [ISIS, Rutherford Appleton Laboratory, Oxford Harwell, Didcot OX11 0QX (United Kingdom); Klotz, S. [IMPMC, CNRS UMR 7590, Université P and M Curie, 4 Place Jussieu, 75252 Paris (France)

    2015-03-28

    Urea, like many network forming compounds, has long been known to form inclusion (guest-host) compounds. Unlike other network formers like water, urea is not known to form such inclusion compounds with simple molecules like hydrogen. Such compounds if they existed would be of interest both for the fundamental insight they provide into molecular bonding and as potential gas storage systems. Urea has been proposed as a potential hydrogen storage material [T. A. Strobel et al., Chem. Phys. Lett. 478, 97 (2009)]. Here, we report the results of high-pressure neutron diffraction studies of urea and D{sub 2} mixtures that indicate no inclusion compound forms up to 3.7 GPa.

  8. Deconvolution estimation of mixture distributions with boundaries

    Science.gov (United States)

    Lee, Mihee; Hall, Peter; Shen, Haipeng; Marron, J. S.; Tolle, Jon; Burch, Christina

    2013-01-01

    In this paper, motivated by an important problem in evolutionary biology, we develop two sieve type estimators for distributions that are mixtures of a finite number of discrete atoms and continuous distributions under the framework of measurement error models. While there is a large literature on deconvolution problems, only two articles have previously addressed the problem taken up in our article, and they use relatively standard Fourier deconvolution. As a result the estimators suggested in those two articles are degraded seriously by boundary effects and negativity. A major contribution of our article is correct handling of boundary effects; our method is asymptotically unbiased at the boundaries, and also is guaranteed to be nonnegative. We use roughness penalization to improve the smoothness of the resulting estimator and reduce the estimation variance. We illustrate the performance of the proposed estimators via our real driving application in evolutionary biology and two simulation studies. Furthermore, we establish asymptotic properties of the proposed estimators. PMID:24009793

  9. Wetting and evaporation of binary mixture drops.

    Science.gov (United States)

    Sefiane, Khellil; David, Samuel; Shanahan, Martin E R

    2008-09-11

    Experimental results on the wetting behavior of water, methanol, and binary mixture sessile drops on a smooth, polymer-coated substrate are reported. The wetting behavior of evaporating water/methanol drops was also studied in a water-saturated environment. Drop parameters (contact angle, shape, and volume) were monitored in time. The effects of the initial relative concentrations on subsequent evaporation and wetting dynamics were investigated. Physical mechanisms responsible for the various types of wetting behavior during different stages are proposed and discussed. Competition between evaporation and hydrodynamic flow are evoked. Using an environment saturated with water vapor allowed further exploration of the controlling mechanisms and underlying processes. Wetting stages attributed to differential evaporation of methanol were identified. Methanol, the more volatile component, evaporates predominantly in the initial stage. The data, however, suggest that a small proportion of methanol remained in the drop after the first stage of evaporation. This residual methanol within the drop seems to influence subsequent wetting behavior strongly.

  10. Dynamics of Polymer Thin Film Mixtures

    Science.gov (United States)

    Besancon, Brian M.; Green, Peter F.; Soles, Christopher L.

    2006-03-01

    We examined the influence of film thickness and composition on the glass transition temperature (Tg) and mean square atomic displacements (MSD) of thin film mixtures of deuterated polystyrene (dPS) and tetramethyl bisphenol-A polycarbonate (TMPC) on Si/SiOx substrates using incoherent elastic neutron scattering (ICNS). The onset of dissipative motions, such as those associated with the glass transition and sub-Tg relaxations, are manifested as ``kinks'' in the curve of elastic intensity (or MSD) versus temperature. From the relevant kinks, the Tg was determined as a function of composition and of film thickness. The dependence of the Tg on film thickness exhibited qualitatively similar trends, at a given composition, as determined by the ICNS and ellipsometry measurements. However, with increasing PS content, the values of Tg measured by INS were consistently larger then those measured by ellipsometry. These results are examined in light of existing models on the thin film glass transition and component blend dynamics.

  11. Performance of asphalt mixture incorporating recycled waste

    Science.gov (United States)

    Hamid, Nor Baizura; Abdullah, Mohd Ezree; Sanik, Mohd Erwan; Mokhtar, Mardiha; Kaamin, Masiri; Raduan, Rasyidah; Ramli, Mohd Zakwan

    2017-12-01

    Nowadays, the amount of premix waste was increased every year, especially at the batching plants. Normally, the waste materials will be discarded without doing any innovative and effective research about those materials. This situation has become one of the global concerns due to the increasing number of premix waste produced every year. Therefore, the aim of this study is to evaluate the performance of hot mix asphalt (HMA) using premix waste on improving asphalt mixture fatigue behaviour. The method used in this study was Superpave mix design method. The sample conducted in this study were 0%, 10%, 20%, 30%, and 100% of premix waste respectively. For a binder test, the laboratory test conducted were penetration test, softening test and thin film oven test while for the performance test were resilient modulus test and indirect tensile fatigue test. From the laboratory test, the resilient modulus test was conducted with two different temperature which was 25°C and 40°C. The result from that test was 20% of premix waste had higher resilient modulus at that two different temperatures compared to another samples. From that test also shown that the sample at the lower temperature which was 25°C has higher resilient modulus compared to the temperature of 40°C. Indirect tensile fatigue test showed that the 30% of premix waste sample was suitable for the modified asphalt mixture with referring to the maximum deformation and strain for comparison control, 10%,20%, and 100% of premix waste samples. So, it can be concluded that premix waste inhibits great potential as road construction material and suitable for repeated traffic loading.

  12. Final report: Properties of mixtures near a phase transition. February 1, 1992 - January 31, 1996

    International Nuclear Information System (INIS)

    Hanley, H.J.M.; Friend, D.G.

    1999-01-01

    This project emphasized the study of systems near phase transitions, and included scattering experiments, computer simulation, and theory of phase transitions. The scattering involved the use of neutrons as well as optical techniques, involved both equilibrium and sheared samples, and included conventional fluids as well as gels, micelles, colloids, and dispersions. Computer simulations and theoretical studies were completed to complement and interpret the microscopic information learned from scattering, and many successes were achieved in furthering our understanding of complex mixtures near the critical locus. The research has led to a number of technical publications and a refinement of our knowledge of phase transition phenomena which has led to improvements in available property databases

  13. The Impact of Organic Aerosol Mixtures on Hygroscopicity: Comparison between Measurements and UNIFAC Model

    Science.gov (United States)

    Lee, J.; Hildemann, L.

    2011-12-01

    The presence of anthropogenic organic compounds in aerosols has the potential to contribute to global climate change by altering the hygroscopic behavior of cloud condensation nuclei. Dicarboxylic acids, including malonic, glutaric, and succinic acids, are among the more frequently measured water-soluble organic compounds in atmospheric aerosols. For solutions containing single or mixed inorganic species, aerosol water uptake has been most commonly modeled using the ZSR method. This approach has also been utilized for solutions containing mixtures of inorganics and organics. For solutions containing a single organic species, the UNIFAC or a modified UNIFAC model has been used, and the features it includes also allow it potentially to be utilized for mixtures. However, there is a dearth of experimental data involving the hygroscopic behavior of organic solution mixtures. In this study, water vapor pressure was measured at 12 C over aqueous bulk solutions containing dicarboxylic acids, using both a quadrupole mass spectrometer and a Baratron pressure transducer. The water uptake of malonic and glutaric acids showed good agreement with limited previous measurements reported in the literature that used an electrodynamic balance (EDB) or bulk solution method. Our experimental measurements of water uptake for malonic and glutaric acids also agreed to within 1% of the predictions using Peng's modified UNIFAC model (Environ. Sci. Technol, 35, 4495-4501, 2001). However, water vapor pressure measurements for solutions containing 50:50 molar mixtures of malonic and glutaric acids were not consistent with predictions using Peng's modified UNIFAC model for mixtures. In the modified UNIFAC model, this mixture of malonic/glutaric acids was predicted to fall roughly midway between the hygroscopicity of the two individual organics. In our measurements, malonic acid exerted the dominant influence in determining the overall water vapor pressure, so that the water uptake of the mixed

  14. Low concentrations of metal mixture exposures have adverse effects on selected biomarkers of Xenopus laevis tadpoles

    Energy Technology Data Exchange (ETDEWEB)

    Yologlu, Ertan, E-mail: ertanyologlu82@gmail.com [Adiyaman University, Faculty of Education, Department of Science Education, 02040 Adiyaman (Turkey); Ozmen, Murat [Inonu University, Laboratory of Environmental Toxicology, Department of Biology, Faculty of Arts & Science, 44280 Malatya (Turkey)

    2015-11-15

    Highlights: • Selected metal mixtures were evaluated for toxicity of safety limit concentrations. • Xenopus laevis tadpoles were used as model test organism. • Combinations of LC{sub 50} and LC{sub 50}/2 caused 100% lethality for some metals. • Metals did not change metallothionein levels in low concentrations. • Selected enzyme activities showed induction after low concentration exposures. - Abstract: Polluted ecosystems may contain mixtures of metals, such that the combinations of metals, even in low concentrations, may cause adverse effects. In the present study, we focused on toxic effects of mixtures of selected metals, the LC{sub 50} values, and also their safety limit in aquatic systems imposed by the European legislation using a model organism. Xenopus laevis tadpoles were used as test organisms. They were exposed to metals or their combinations due to 96-h LC{sub 50} values. Glutathione S-transferase (GST), glutathione reductase (GR), acetylcholinesterase (AChE), carboxylesterase (CaE), glutathione peroxidase (GPx), and catalase (CAT) levels were evaluated. Metallothionein concentrations were also determined. The LC{sub 50}s for Cd, Pb, and Cu were calculated as 5.81 mg AI/L, 123.05 mg AI/L, and 0.85 mg AI/L, respectively. Low lethality ratios were observed with unary exposure of each metal in lower concentrations. Double or triple combinations of LC{sub 50} and LC{sub 50}/2 concentrations caused 100% lethality with Cd + Cu and Pb + Cd + Cu mixtures, while the Pb + Cu mixture also caused high lethal ratios. The selected enzyme activities were significantly affected by metals or mixtures, and dose-related effects were determined. The metallothionein levels generally increased as related to concentration in unary metals and mixtures. Acceptable limit values of unary metals and mixtures did not significantly change metallothionein levels. The results suggest that oxidative stress-related mechanisms are involved in the toxicity induced by selected

  15. The Involved Ostrich

    DEFF Research Database (Denmark)

    Davies, Andrea; Dobscha, Susan; Geiger, Susi

    2008-01-01

    and technical items. This research also revealed that men partook in highly masculinized forms of “nesting,” and in general shunned pregnancy book reading; although some did engage in “research” activities such as searching the internet for product safety information. We conclude from this study...... that the transition into parenthood can be difficult for men due to their lack of a physical connection to the pregnancy, a perception that the baby industry is not designed for them, the continuance of male stereotypes in the media, and also the time available to men to become involved in consumption activities...

  16. Thermal analysis of pyrotechnic mixture-fireworks, atom-bomb

    International Nuclear Information System (INIS)

    Rajendran, Jeya; Thanulingam, T.L.

    2008-01-01

    Sound level produced from two varieties of sound producing fireworks of atom-bomb, cake bomb and thunder bomb were measured. The pyrotechnic mixture, KNO 3 /S/Al(H 3 BO 3 ) of compositions 57.5/19.9/22.1(0.5)% very much similar to commercial atom-bomb were taken and five cake bomb and seven thunder bomb with different net weight of chemicals were manufactured specifically for analysis. Cake bomb with 1g pyrotechnic mixture and thunder bomb with 2g pyrotechnic mixture produce -3 . Ignition temperature of the mixture is above the melting point of the metallic fuel, Al (660 deg C) and self propagating decomposition occurred at high temperature. The pyrotechnic mixture, KNO 3 /S/Al(H 3 BO 3 ) is a safe mixture from accidental factor, static electricity. DSC studies indicate slight formation of potassium nitrite with evolution of NO above 400 deg C. (author)

  17. Odor mixture alters neural resources during symbolic problem solving.

    Science.gov (United States)

    Lorig, Tyler S; Malin, Emily L; Horwitz, Julie E

    2005-05-01

    The smell of a cup of coffee is produced by many different odor chemicals combined in a mixture, yet the perception of that odor is of a single unified whole. Recent evidence has demonstrated that mixtures of odors share some of the same spatiotemporal features of speech sounds and may use similar brain resources in associating those features with the symbols they represent. This experiment investigated the hypothesis that an odor mixture would interfere with a math task that requires symbolic but not spatial processing. Results indicated the pattern of brain electrical activity was similar for the single odors and the mixture during spatial processing. During solution of the task requiring symbolic processing, the odor mixture produced a pattern of brain electrical activity different from the single odorants. These data suggest that the perception of odor mixtures may use some of the same resources associated with symbolic processing.

  18. Residual-based model diagnosis methods for mixture cure models.

    Science.gov (United States)

    Peng, Yingwei; Taylor, Jeremy M G

    2017-06-01

    Model diagnosis, an important issue in statistical modeling, has not yet been addressed adequately for cure models. We focus on mixture cure models in this work and propose some residual-based methods to examine the fit of the mixture cure model, particularly the fit of the latency part of the mixture cure model. The new methods extend the classical residual-based methods to the mixture cure model. Numerical work shows that the proposed methods are capable of detecting lack-of-fit of a mixture cure model, particularly in the latency part, such as outliers, improper covariate functional form, or nonproportionality in hazards if the proportional hazards assumption is employed in the latency part. The methods are illustrated with two real data sets that were previously analyzed with mixture cure models. © 2016, The International Biometric Society.

  19. Semiparametric accelerated failure time cure rate mixture models with competing risks.

    Science.gov (United States)

    Choi, Sangbum; Zhu, Liang; Huang, Xuelin

    2018-01-15

    Modern medical treatments have substantially improved survival rates for many chronic diseases and have generated considerable interest in developing cure fraction models for survival data with a non-ignorable cured proportion. Statistical analysis of such data may be further complicated by competing risks that involve multiple types of endpoints. Regression analysis of competing risks is typically undertaken via a proportional hazards model adapted on cause-specific hazard or subdistribution hazard. In this article, we propose an alternative approach that treats competing events as distinct outcomes in a mixture. We consider semiparametric accelerated failure time models for the cause-conditional survival function that are combined through a multinomial logistic model within the cure-mixture modeling framework. The cure-mixture approach to competing risks provides a means to determine the overall effect of a treatment and insights into how this treatment modifies the components of the mixture in the presence of a cure fraction. The regression and nonparametric parameters are estimated by a nonparametric kernel-based maximum likelihood estimation method. Variance estimation is achieved through resampling methods for the kernel-smoothed likelihood function. Simulation studies show that the procedures work well in practical settings. Application to a sarcoma study demonstrates the use of the proposed method for competing risk data with a cure fraction. Copyright © 2017 John Wiley & Sons, Ltd.

  20. Problems in assessing the risks of mixtures of contaminants in drinking water

    International Nuclear Information System (INIS)

    Vanderslice, R.R.; Orme, J.; Ohanian, E.V.; Sonich-Mullin, C.

    1989-01-01

    In conducting risk assessments on drinking water contaminants, the U.S. Environmental Protection Agency (EPA) attempts to evaluate all available toxicity data to develop Health Advisory (HA) and Maximum Contaminant Level Goal (MCLG) values. The EPA often has grappled with the issues surrounding the toxicity of chemical mixtures, including radioactive contaminants, nitrate/nitrite, and trihalomethanes (THMs). In evaluating the toxicity of chemical mixtures, the EPA's immediate concern is whether the individual HA values and MCLGs are protecting public health when multiple contaminants are present in drinking water. Potential toxic interactions between drinking water contaminants are difficult to predict because experimental studies are generally performed only at high doses relative to environmental levels. Although the contamination of drinking water involves mixtures of contaminants, drinking water regulations are generally based on an assessment of the risks of individual contaminants. This paper discusses three issues of major concern to the EPA: the synergistic effects of solvent mixtures, vehicle effects in laboratory studies, and setting standards for essential trace nutrients where the absorption and/or toxicity are affected by an individual's nutritional status or other dietary components. 12 references

  1. Binary mixtures of ionic liquids: a joint approach to investigate their properties and catalytic ability.

    Science.gov (United States)

    D'Anna, Francesca; Marullo, Salvatore; Vitale, Paola; Noto, Renato

    2012-05-14

    The growing interest in the properties and applications of ionic liquids has recently led to research into the possibility of using their binary mixtures. This work reports on the effects of binary mixtures of ionic liquids on the outcome of organic reactions such as the mononuclear rearrangement of heterocycles and the solvatochromic behavior of Nile Red. Binary mixtures formed by ionic liquids differing in the structure of the cation and the anion are taken into account. In particular, ionic liquids such as 1-benzyl-3-butylimidazolium bis(trifluoromethanesulfonyl)imide, 1-(2,3,4,5,6-pentafluorobenzyl)-3-butylimidazolium bis(trifluoromethanesulfonyl)imide, and 1-benzyl-3-butylimidazolium tetrafluoroborate, are studied. To achieve a deep understanding of the properties of ionic-liquid binary mixtures, their three-dimensional organization was analyzed by a combination of resonance light scattering, UV/Vis spectroscopy, and (1)H and (19)F NMR spectroscopy. Data collected herein evidence that the most significant changes in the ionic lattice structure, and consequently the most pronounced effects exerted as solvent media, occur when the studied system involves a blend of different anions. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Dual-Mode Measurement and Theoretical Analysis of Evaporation Kinetics of Binary Mixtures

    Science.gov (United States)

    Song, Hanyu; He, Chi-Ruei; Basdeo, Carl; Li, Ji-Qin; Ye, Dezhuang; Kalonia, Devendra; Li, Si-Yu; Fan, Tai-Hsi

    Theoretical and experimental investigations are presented for the precision measurement of evaporation kinetics of binary mixtures using a quartz crystal resonator. A thin layer of light alcohol mixture including a volatile (methanol) and a much less volatile (1-butanol) components is deployed on top of the resonator. The normal or acoustic mode is to detect the moving liquid-vapor interface due to evaporation with a great spatial precision on the order of microns, and simultaneously the shear mode is used for in-situ detection of point viscosity or concentration of the mixture near the resonator. A one-dimensional theoretical model is developed to describe the underlying mass transfer and interfacial transport phenomena. Along with the modeling results, the transient evaporation kinetics, moving interface, and the stratification of viscosity of the liquid mixture during evaporation are simultaneously measured by the impedance response of the shear and longitudinal waves emitted from the resonator. The system can be used to characterize complicated evaporation kinetics involving multi-component fuels. American Chemical Society Petroleum Research Fund, NSF CMMI-0952646.

  3. Hydrogen separation from multicomponent gas mixtures containing CO, N2 and CO2 using Matrimid asymmetric hollow fiber membranes

    NARCIS (Netherlands)

    David, Oana C.; Gorri, Daniel; Nijmeijer, Dorothea C.; Ortiz, Inmaculada; Urtiaga, Ane

    2012-01-01

    The application of hollow fiber membranes for the separation of industrial gas mixtures relies on the correct characterization of the permeation of the involved gaseous components through the hollow fiber membranes. Thus, this study is focused on the characterization of the permeation through

  4. Global phase equilibrium calculations: Critical lines, critical end points and liquid-liquid-vapour equilibrium in binary mixtures

    DEFF Research Database (Denmark)

    Cismondi, Martin; Michelsen, Michael Locht

    2007-01-01

    A general strategy for global phase equilibrium calculations (GPEC) in binary mixtures is presented in this work along with specific methods for calculation of the different parts involved. A Newton procedure using composition, temperature and Volume as independent variables is used for calculati...

  5. Mixture of Regression Models with Single-Index

    OpenAIRE

    Xiang, Sijia; Yao, Weixin

    2016-01-01

    In this article, we propose a class of semiparametric mixture regression models with single-index. We argue that many recently proposed semiparametric/nonparametric mixture regression models can be considered special cases of the proposed model. However, unlike existing semiparametric mixture regression models, the new pro- posed model can easily incorporate multivariate predictors into the nonparametric components. Backfitting estimates and the corresponding algorithms have been proposed for...

  6. Statistical Description of Segregation in a Powder Mixture

    DEFF Research Database (Denmark)

    Chapiro, Alexander; Stenby, Erling Halfdan

    1996-01-01

    In this paper we apply the statistical mechanics of powders to describe a segregated state in a mixture of grains of different sizes. Variation of the density of a packing with depth arising due to changes of particle configurations is studied. The statistical mechanics of powders is generalized...... in such a way as to consider not only binary mixtures (as its first formulation by A. Mehta and S.F. Edwards), but also polydisperse mixtures of particles....

  7. Bayesian D-Optimal Choice Designs for Mixtures

    OpenAIRE

    Aiste Ruseckaite; Peter Goos; Dennis Fok

    2014-01-01

    markdownabstract__Abstract__ Consumer products and services can often be described as mixtures of ingredients. Examples are the mixture of ingredients in a cocktail and the mixture of different components of waiting time (e.g., in-vehicle and out-of-vehicle travel time) in a transportation setting. Choice experiments may help to determine how the respondents' choice of a product or service is affected by the combination of ingredients. In such studies, individuals are confronted with sets of ...

  8. Antiandrogenic activity of phthalate mixtures: Validity of concentration addition

    Energy Technology Data Exchange (ETDEWEB)

    Christen, Verena [University of Applied Sciences Northwestern Switzerland, School of Life Sciences, Gründenstrasse 40, CH-4132 Muttenz (Switzerland); Crettaz, Pierre; Oberli-Schrämmli, Aurelia [Swiss Federal Office of Public Health, Division Chemical Products, 3003 Bern (Switzerland); Fent, Karl, E-mail: karl.fent@bluewin.ch [University of Applied Sciences Northwestern Switzerland, School of Life Sciences, Gründenstrasse 40, CH-4132 Muttenz (Switzerland); Swiss Federal Institute of Technology Zürich (ETH Zürich), Department of Environmental Sciences, 8092 Zürich (Switzerland)

    2012-03-01

    Phthalates and bisphenol A have very widespread use leading to significant exposure of humans. They are suspected to interfere with the endocrine system, including the androgen, estrogen and the thyroid hormone system. Here we analyzed the antiandrogenic activity of six binary, and one ternary mixture of phthalates exhibiting complete antiandrogenic dose–response curves, and binary mixtures of phthalates and bisphenol A at equi-effective concentrations of EC{sub 10}, EC{sub 25} and EC{sub 50} in MDA-kb2 cells. Mixture activity followed the concentration addition (CA) model with a tendency to synergism at high and antagonism at low concentrations. Isoboles and the toxic unit approach (TUA) confirmed the additive to synergistic activity of the binary mixtures BBP + DBP, DBP + DEP and DEP + BPA at high concentrations. Both methods indicate a tendency to antagonism for the EC{sub 10} mixtures BBP + DBP, BBP + DEP and DBP + DEP, and the EC{sub 25} mixture of DBP + BPA. A ternary mixture revealed synergism at the EC{sub 50}, and weak antagonistic activity at the EC{sub 25} level by the TUA. A mixture of five phthalates representing a human urine composition and reflecting exposure to corresponding parent compounds showed no antiandrogenic activity. Our study demonstrates that CA is an appropriate concept to account for mixture effects of antiandrogenic phthalates and bisphenol A. The interaction indicates a departure from additivity to antagonism at low concentrations, probably due to interaction with the androgen receptor and/or cofactors. This study emphasizes that a risk assessment of phthalates should account for mixture effects by applying the CA concept. -- Highlights: ► Antiandrogenic activity of mixtures of 2 and 3 phthalates are assessed in MDA-kb2 cells. ► Mixture activities followed the concentration addition model. ► A tendency to synergism at high and antagonism at low levels occurred.

  9. Genetic Evidence for Recent Population Mixture in India

    OpenAIRE

    Moorjani, Priya; Thangaraj, Kumarasamy; Patterson, Nick; Lipson, Mark; Loh, Po-Ru; Govindaraj, Periyasamy; Berger, Bonnie; Reich, David; Singh, Lalji

    2013-01-01

    Most Indian groups descend from a mixture of two genetically divergent populations: Ancestral North Indians (ANI) related to Central Asians, Middle Easterners, Caucasians, and Europeans; and Ancestral South Indians (ASI) not closely related to groups outside the subcontinent. The date of mixture is unknown but has implications for understanding Indian history. We report genome-wide data from 73 groups from the Indian subcontinent and analyze linkage disequilibrium to estimate ANI-ASI mixture ...

  10. Mixture Experiments and their Application in Agricultural Research

    OpenAIRE

    Raza, Irum; Masood, M. Asif; Mahmood, Rashid

    2013-01-01

    The present study was designed to show the applicability of Mixture designs in Agricultural Research System and to fit an appropriate mixture regression model making response variables as functions of the proportions of the mixture components. Data on four components namely neem oil, garlic oil, clove oil and tobacco extract (ml) were collected from field experiment conducted by Honeybee Research Institute, NARC. The main goal of the experiment was to check whether blending two components hav...

  11. Determination of thermal conductivity in foundry mould mixtures

    Directory of Open Access Journals (Sweden)

    G. Solenički

    2010-01-01

    Full Text Available For a thorough understanding of the behaviour of foundry mould mixtures, a good knowledge of thermal properties of mould materials is needed. Laboratory determination of thermal conductivity of mould mixtures enables a better control over scabbing defects which are a major problem in green sand mould mixtures. A special instrument has been designed for that purpose and it is described in this work.

  12. DURABILITY OF ASPHALT CONCRETE MIXTURES USING DOLOMITE AGGREGATES

    Directory of Open Access Journals (Sweden)

    Imad Al-Shalout

    2015-12-01

    Full Text Available This study deals with the durability of asphalt concrete, including the effects of different gradations, compaction temperatures and immersion time on the durability potential of mixtures. The specific objectives of this study are: to investigate the effect of compaction temperature on the mechanical properties of asphalt concrete mixtures; investigate the effect of bitumen content and different aggregate gradations on the durability potential of bituminous mixtures.

  13. Public interest group involvement

    International Nuclear Information System (INIS)

    Shelley, P.

    1986-01-01

    Including public interest groups in the siting process for nuclear waste disposal facilities is of great importance. Controversial sitings often result in litigation, but involving public interest groups early in the process will lessen the change of this. They act as surrogates for the general public and should be considered as members of the team. It is important to remember though, that all public interest groups are different. In choosing public panels such as public advisory committees, members should not be chosen on the basis of some quota. Opposition groups should not be excluded. Also, it is important to put the right person in charge of the committee. The goal of public involvement is to identify the conflicts. This must be done during the decision process, because conflicts must be known before they can be eliminated. Regarding litigation, it is important to ease through and around legal battles. If the siting process has integrity and a good faith effort has been shown, the court should uphold the effort. In addition, it is important to be negotiable and to eliminate shortcuts

  14. Mathematical Model for Multicomponent Adsorption Equilibria Using Only Pure Component Data

    DEFF Research Database (Denmark)

    Marcussen, Lis

    2000-01-01

    A mathematical model for nonideal adsorption equilibria in multicomponent mixtures is developed. It is applied with good results for pure substances and for prediction of strongly nonideal multicomponent equilibria using only pure component data. The model accounts for adsorbent-adsorbate and ads......A mathematical model for nonideal adsorption equilibria in multicomponent mixtures is developed. It is applied with good results for pure substances and for prediction of strongly nonideal multicomponent equilibria using only pure component data. The model accounts for adsorbent...

  15. Tutorial for mixture-process experiments with an industrial application

    Directory of Open Access Journals (Sweden)

    Luiz Henrique Abreu Dal Bello

    2011-12-01

    Full Text Available This article presents a tutorial on mixture-process experiments and a case study of a chemical compound used in the delay mechanism for starting a rocket engine. The compound consists in a three-component mixture. Besides the mixture components, two process variables are considered. For the model selection, the use of an information criterion showed to be efficient in the case under study. A linear regression model was fitted. Through the developed model, the optimal proportions of the mixture components and the levels of the process variables were determined.

  16. Designing optimal mixtures using generalized disjunctive programming: Hull relaxations

    OpenAIRE

    Jonuzaj, S; Adjiman, CSJ

    2016-01-01

    A general modeling framework for mixture design problems, which integrates Generalized Disjunctive Programming (GDP) into the Computer-Aided Mixture/blend Design (CAMbD) framework, was recently proposed (S. Jonuzaj, P.T. Akula, P.-M. Kleniati, C.S. Adjiman, 2016. AIChE Journal 62, 1616???1633). In this paper we derive Hull Relaxations (HR) of GDP mixture design problems as an alternative to the big-M (BM) approach presented in this earlier work. We show that in restricted mixture design probl...

  17. [Construction of Three-Dimensional Isobologram for Ternary Pollutant Mixtures].

    Science.gov (United States)

    2015-12-01

    Tongji University, Shanghai 200092, China) Isobolographic analysis was widely used in the interaction assessment of binary mixtures. However, how to construct a three-dimensional (3D) isobologram for the assessment of toxicity interaction within ternary mixtures is still not reported up to date. The main purpose of this paper is to develop a 3D isobologram where the relative concentrations of three components are acted as three coordinate axes in 3D space to examine the toxicity interaction within ternary mixtures. Taking six commonly used pesticides in China, including three herbicides (2, 4-D, desmetryne and simetryn) and three insecticides ( dimethoate, imidacloprid and propoxur) as the mixture components, the uniform design ray procedure (UD-Ray) was used to rationally design the concentration composition of various components in the ternary mixtures so that effectively and comprehensively reflected the variety of actual environmental concentrations. The luminescent inhibition toxicities of single pesticides and their ternary mixtures to Vibrio fischeri at various concentration levels were determined by the microplate toxicity analysis. Selecting concentration addition (CA) as the addition reference, 3D isobolograms were constructed to study the toxicity interactions of various ternary mixtures. The results showed that the 3D isobologram could clearly and directly exhibit the toxicity interactions of ternary mixtures, and extend the use of isobolographic analysis into the ternary mixtures.

  18. Communication: Modeling electrolyte mixtures with concentration dependent dielectric permittivity

    Science.gov (United States)

    Chen, Hsieh; Panagiotopoulos, Athanassios Z.

    2018-01-01

    We report a new implicit-solvent simulation model for electrolyte mixtures based on the concept of concentration dependent dielectric permittivity. A combining rule is found to predict the dielectric permittivity of electrolyte mixtures based on the experimentally measured dielectric permittivity for pure electrolytes as well as the mole fractions of the electrolytes in mixtures. Using grand canonical Monte Carlo simulations, we demonstrate that this approach allows us to accurately reproduce the mean ionic activity coefficients of NaCl in NaCl-CaCl2 mixtures at ionic strengths up to I = 3M. These results are important for thermodynamic studies of geologically relevant brines and physiological fluids.

  19. Initiation of explosive mixtures having multi-sized structures

    Science.gov (United States)

    Vasil'ev, A. A.; Vasiliev, V. A.; Trotsyuk, A. V.

    2016-10-01

    Theory of strong blast was used as the basis for the experimental method of determining of the energy of source which provides the initiation of combustible mixture. For mono-fuel mixtures the following parameters were experimentally determined at testing: the critical initiation energy of a cylindrical detonation wave in mixtures 2H2+O2 and C2H2+2.5O2 (exploding wire); the critical initiation energy of a spherical detonation in a mixture of C2H2+2.5O2 (electrical discharge). Similarly, for the double-fuel mixtures of acetylene - nitrous oxide - oxygen (having bifurcation cellular structures) the critical initiation energy of spherical wave was determined also. It was found that for the stoichiometric mixture on both fuel components the critical energy of mixture with the bifurcation structure was undervalued by several times in comparison with the value of the critical energy for the mono-fuel mixture, in which the cell size at a given pressure is determined by the large scale of bifurcation cells. This result shows the decrease of the critical energy with an increase of the number of "hot spots", which are the numerous areas of collision of the transverse waves of large and small scales in a mixture with bifurcation properties.

  20. Effect of Mixture Pressure and Equivalence Ratio on Detonation Cell Size for Hydrogen-Air Mixtures

    Science.gov (United States)

    2015-06-01

    mixture pressure detonation cell sizes are important for scaling the combustion chambers, and before this research no data existed for hydrogen and air...Introduction General Issue Pressure gain combustors have the potential to replace traditional combustions systems in gas turbine engines (Tellefsen et al... combustion has not been fully incorporated into turbine engines. In order to fully integrate RDEs into turbine engines, RDEs must be able to function