WorldWideScience

Sample records for chemical mixtures proceedings

  1. 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.

  2. Toxicological evaluation of chemical mixtures

    NARCIS (Netherlands)

    Feron, V.J.; Groten, J.P.

    2002-01-01

    This paper addresses major developments in the safety evaluation of chemical mixtures during the past 15 years, reviews today's state of the art of mixture toxicology, and discusses challenges ahead. Well-thought-out tailor-made mechanistic and empirical designs for studying the toxicity of mixtures

  3. Toxicological evaluation of chemical mixtures.

    Science.gov (United States)

    Feron, V J; Groten, J P

    2002-06-01

    This paper addresses major developments in the safety evaluation of chemical mixtures during the past 15 years, reviews today's state of the art of mixture toxicology, and discusses challenges ahead. Well-thought-out tailor-made mechanistic and empirical designs for studying the toxicity of mixtures have gradually substituted trial-and-error approaches, improving the insight into the testability of joint action and interaction of constituents of mixtures. The acquired knowledge has successfully been used to evaluate the safety of combined exposures and complex mixtures such as, for example, the atmosphere at hazardous waste sites, drinking water disinfection by-products, natural flavouring complexes, and the combined intake of food additives. To consolidate the scientific foundation of mixture toxicology, studies are in progress to revisit the biological concepts and mathematics underlying formulas for low-dose extrapolation and risk assessment of chemical mixtures. Conspicuous developments include the production of new computer programs applicable to mixture research (CombiTool, BioMol, Reaction Network Modelling), the application of functional genomics and proteomics to mixture studies, the use of nano-optochemical sensors for in vivo imaging of physiological processes in cells, and the application of optical sensor micro- and nano-arrays for complex sample analysis. Clearly, the input of theoretical biologists, biomathematicians and bioengineers in mixture toxicology is essential for the development of this challenging branch of toxicology into a scientific subdiscipline of full value. PMID:11983277

  4. Mixture toxicity of PBT-like chemicals

    DEFF Research Database (Denmark)

    Syberg, Kristian; Dai, Lina; Ramskov, Tina;

    Even though most chemicals regulation is still conducted on a chemical by chemical basis, mixture toxicity is achieving increasing attention. The scientific understanding has increased substantially in the last decades, and a general consensus now seems to have been acieved that concentration...... addition is a suitable model for default estimations of mixture effects. One of the major challenges is therefore how to select specific chemicals for actual mixture toxicity assessments. Persistant chemicals are likely to be present in the environment for an extended period of time, thus increasing the...... likelihood of them being present in environmentally found mixtures. Persistant, bioaccumulative and toxic (PBT) chemicals are therefore a highly relevant group of chemicals to consider for mixture toxicity regulation. The present study evaluates to what extent a number of PBT-like chemicals posess concern...

  5. Predicting skin permeability from complex chemical mixtures

    International Nuclear Information System (INIS)

    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 + aΣα 2H + bΣβ 2H + sπ 2H + rR 2 + vV x where Σα 2H is the hydrogen-bond donor acidity, Σβ 2H is the hydrogen-bond acceptor basicity, π 2H is the dipolarity/polarizability, R 2 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, ρ-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 as the focus of these studies was

  6. 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 de

  7. 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

  8. Quasi-chemical approximation for polyatomic mixtures

    CERN Document Server

    Dávila, M V; Matoz-Fernandez, D A; Ramirez-Pastor, A J

    2016-01-01

    The statistical thermodynamics of binary mixtures of polyatomic species was developed on a generalization in the spirit of the lattice-gas model and the quasi-chemical approximation (QCA). The new theoretical framework is obtained by combining: (i) the exact analytical expression for the partition function of non-interacting mixtures of linear $k$-mers and $l$-mers (species occupying $k$ sites and $l$ sites, respectively) adsorbed in one dimension, and its extension to higher dimensions; and (ii) a generalization of the classical QCA for multicomponent adsorbates and multisite-occupancy adsorption. The process is analyzed through the partial adsorption isotherms corresponding to both species of the mixture. Comparisons with analytical data from Bragg-Williams approximation (BWA) and Monte Carlo simulations are performed in order to test the validity of the theoretical model. Even though a good fitting is obtained from BWA, it is found that QCA provides a more accurate description of the phenomenon of adsorpti...

  9. 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.

  10. 21 CFR 1310.13 - Exemption of chemical mixtures; application.

    Science.gov (United States)

    2010-04-01

    ... REPORTS OF LISTED CHEMICALS AND CERTAIN MACHINES § 1310.13 Exemption of chemical mixtures; application. (a... complete qualitative and quantitative composition of the chemical mixture (including all listed and all non... mixture shall notify DEA in writing, of any change in the quantitative or qualitative composition of...

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

    International Nuclear Information System (INIS)

    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

  12. 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.

  13. Interval-Passing Algorithm for Chemical Mixture Estimation

    OpenAIRE

    Danjean, Ludovic; Vasic, Bane; Marcellin, Michael; Declercq, David

    2013-01-01

    International audience In this letter we propose a compressive sensing scheme for the mixture estimation problem in spectroscopy. We show that by applying an appropriate measurement matrix on the chemical mixture spectrum, we obtain an overall measurement matrix which is sparse. This enables the use of a low-complexity iterative reconstruction algorithm, called the interval-passing algorithm, to estimate the concentration of each chemical present in the mixture. Simulation results for the ...

  14. Dynamics of transient metastable states in mixtures under coupled phase ordering and chemical demixing

    OpenAIRE

    Soulé, Ezequiel R.; Rey, Alejandro D.

    2013-01-01

    We present theory and simulation of simultaneous chemical demixing and phase ordering in a polymer-liquid crystal mixture in conditions where isotropic-isotropic phase separation is metastable with respect to isotropic-nematic phase transition. In the case the mechanism is nucleation and growth, it is found that mesophase growth proceeds by a transient metastable phase that surround the ordered phase, and whose lifetime is a function of the ratio of diffusional to orientational mobilities. In...

  15. Safety evaluation of chemical mixtures and combinations of chemical and non-chemical stressors.

    Science.gov (United States)

    Jonker, D; Freidig, A P; Groten, J P; de Hollander, A E M; Stierum, R H; Woutersen, R A; Feron, V J

    2004-01-01

    Recent developments in hazard identification and risk assessment of chemical mixtures are reviewed. Empirical, descriptive approaches to study and characterize the toxicity of mixtures have dominated during the past two decades, but an increasing number of mechanistic approaches have made their entry into mixture toxicology. A series of empirical studies with simple chemical mixtures in rats is described in some detail because of the important lessons from this work. The development of regulatory guidelines for the toxicological evaluation of chemical mixtures is discussed briefly. Current issues in mixture toxicology include the adverse health effects of ambient air pollution; the application of such modern, sophisticated methodologies as genomics, bioinformatics, and physiologically based pharmacokinetic modeling; and databases for mixture toxicity. Finally, the state of the art of our knowledge on the potential adverse health effects of combined exposures to chemicals and non-chemical stressors (noise, heat/cold, microorganisms, immobilization, restraint, or transportation), research initiatives in these fields, and the development of an indicator for the cumulative health impact of multiple environmental exposures are discussed. PMID:15329008

  16. Identification and Prioritization of Chemical Mixtures from Environmental Residue Data

    Science.gov (United States)

    High throughput toxicity testing has greatly improved the speed at which single chemicals can be screened using in vitro methods. However, people are not exposed to a single chemical at a time, rather to a mixture of chemicals. Even with the increased speed of these methods, te...

  17. Toxicological evaluation and risk assessment of chemical mixtures

    NARCIS (Netherlands)

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

    1998-01-01

    A major objective of combination toxicology is to establish whether a mixture of chemicals will result in an effect similar to that expected on the basis of additivity. This requires understanding of the basic concepts of the combined toxicological action of the compounds of the mixture: simple simi

  18. 21 CFR 1310.12 - Exempt chemical mixtures.

    Science.gov (United States)

    2010-04-01

    .... Ergotamine and its salts 8676 Not exempt at any concentration Chemical mixtures containing amount of any ergotamine, including its salts, are not exempt. Ethylamine and its salts 8678 20% by Weight or...

  19. Tools and perspectives for assessing chemical mixtures and multiple stressors

    DEFF Research Database (Denmark)

    Løkke, Hans; Ragas, Ad M. J.; Holmstrup, Martin

    2013-01-01

    integration of methods for human and ecological risk assessment. A mechanistically based model, considering uptake and toxicity as a processes in time, has demonstrated considerable potential for predicting mixture effects in ecotoxicology, but requires the measurement of toxicity endpoints at different...... moments in time. Within a novel framework for risk assessment of chemical mixtures, the importance of environmental factors on toxicokinetic processes is highlighted. A new paradigm for applying personal characteristics that determine individual exposure and sensitivity in human risk assessment is...

  20. Toxicology of chemical mixtures: a challenging quest along empirical sciences.

    Science.gov (United States)

    Groten, John P; Heijne, Wilbert H M; Stierum, Rob H; Freidig, Andreas P; Feron, Victor J

    2004-12-01

    This paper describes the "quest" of our institute trying to assess the toxicology of chemical mixtures. In this overview, we will discuss some critical developments in hazard identification and risk assessment of chemical mixtures during these past 15 years. We will stand still at empirical and mechanistic modeling. "Empirical" means that only information on doses or concentrations and effects is available in addition to an often empirically selected quantitative dose-response relationship. Empirical models have played a dominant role in the last decade to identify health and safety characteristics of chemical mixtures. Many of these models are based on the work of pioneers in mixture toxicology who defined three basic types of action for combinations of chemicals: simple similar action, simple dissimilar action and interaction. Nowadays, empirical models are mainly based on response-surface analysis and make use of advanced statistical designs. However, possible interactions between components in a mixture can also be given in terms of mechanistic models. In terms of "mechanistic" (or biological) understanding, interactions between compounds may occur in the kinetic phase (processes of uptake, distribution, metabolism and excretion) or in the dynamic phase (effects of chemicals on the receptor, cellular target or organ). A biological phenomenon such as competitive agonism as described for mixtures of drugs (biotransformation enzymes) or sensory irritants (nerve receptors) can accurately predict the effect of any of these mixtures. Thus, far mechanistic and empirical analyses of interactions are usually unrelated. It is one of the future challenges for mixtures research to combine information from both approaches. Also, our current biology-based models have their limitations, since they cannot integrate every relevant biological mechanism. In this respect, mechanistic modeling of mixtures may benefit from the developments coming from the arena of molecular biology

  1. Statistically designed experiments to screen chemical mixtures for possible interactions

    NARCIS (Netherlands)

    Groten, J.P.; Tajima, O.; Feron, V.J.; Schoen, E.D.

    1998-01-01

    For the accurate analysis of possible interactive effects of chemicals in a defined mixture, statistical designs are necessary to develop clear and manageable experiments. For instance, factorial designs have been successfully used to detect two-factor interactions. Particularly useful for this purp

  2. Chemometrics as a tool to analyse complex chemical mixtures

    DEFF Research Database (Denmark)

    Christensen, J. H.

    describes the development of such methods for assessing the identity (chemical fingerprinting) and fate (e.g. biodegradation) of petroleum hydrocarbon mixtures. The methods comply with the general concept that suitable methods must be rapid and inexpensive, objective with limited human in- tervention and at...

  3. Approximate modeling of chemically reacting gas mixtures of detonation products

    International Nuclear Information System (INIS)

    Based on the assumption of the existence of the partial chemical equilibrium in the detonation products, an approximate method for calculating composition of the detonation products has been developed. The method uses the assumption of the existence of extremum of Helmholtz free energy for a given density, temperature, and molecular weight of the detonation products mixture

  4. Radiation induced chemical reaction of carbon monoxide and hydrogen mixture

    International Nuclear Information System (INIS)

    Previous studies of radiation induced chemical reactions of CO-H2 mixture have revealed that the yields of oxygen containing products were larger than those of hydrocarbons. In the present study, methane was added to CO-H2 mixture in order to increase further the yields of the oxygen containing products. The yields of most products except a few products such as formaldehyde increased with the addition of small amount of methane. Especially, the yields of trioxane and tetraoxane gave the maximum values when CO-H2 mixture containing 1 mol% methane was irradiated. When large amounts of methane were added to the mixture, the yields of aldehydes and carboxylic acids having more than two carbon atoms increased, whereas those of trioxane and tetraoxane decreased. From the study at reaction temperature over the range of 200 to 473 K, it was found that the yields of aldehydes and carboxylic acids showed maxima at 323 K. The studies on the effects of addition of cationic scavenger (NH3) and radical scavenger (O2) on the products yields were also carried out on the CO-H2-CH4 mixture. (author)

  5. Compendium of shock wave data. Section C. Organic compounds excluding hydrocarbons. Section D. Mixtures. Section E. Mixtures and solutions without chemical characterization. Compendium index

    International Nuclear Information System (INIS)

    This volume lists thermodynamic data for organic compounds excluding hydrocarbons, mixtures, and mixtures and solutions without chemical characterization. Alloys and some minerals are included among the mixtures. This volume also contains the index for the three-volume compendium

  6. Sensing a Changing Chemical Mixture Using an Electronic Nose

    Science.gov (United States)

    Duong, Tuan; Ryan, Margaret

    2008-01-01

    A method of using an electronic nose to detect an airborne mixture of known chemical compounds and measure the temporally varying concentrations of the individual compounds is undergoing development. In a typical intended application, the method would be used to monitor the air in an inhabited space (e.g., the interior of a building) for the release of solvents, toxic fumes, and other compounds that are regarded as contaminants. At the present state of development, the method affords a capability for identifying and quantitating one or two compounds that are members of a set of some number (typically of the order of a dozen) known compounds. In principle, the method could be extended to enable monitoring of more than two compounds. An electronic nose consists of an array of sensors, typically made from polymer carbon composites, the electrical resistances of which change upon exposure to a variety of chemicals. By design, each sensor is unique in its responses to these chemicals: some or all of the sensitivities of a given sensor to the various vapors differ from the corresponding sensitivities of other sensors. In general, the responses of the sensors are nonlinear functions of the concentrations of the chemicals. Hence, mathematically, the monitoring problem is to solve the set of time-dependent nonlinear equations for the sensor responses to obtain the time dependent concentrations of individual compounds. In the present developmental method, successive approximations of the solution are generated by a learning algorithm based on independent-component analysis (ICA) an established information theoretic approach for transforming a vector of observed interdependent signals into a set of signals that are as nearly statistically independent as possible.

  7. Chemometrics as a tool to analyse complex chemical mixtures: environmental forensics and fate of oil spills

    OpenAIRE

    Christensen, Jan H.

    2005-01-01

    Chemical characterisation of contaminant mixtures is important for environmental forensics and risk assessment. The great challenge in future research lies in developing suitable, rapid, reliable and objective methods for analysis of the composition of complex chemical mixtures. This thesis describes the development of such methods for assessing the identity (chemical fingerprinting) and fate (e.g. biodegradation) of petroleum hydrocarbon mixtures. The methods comply with the g...

  8. A low dose chemical mixture modulates the effect of PFNA in male rats

    DEFF Research Database (Denmark)

    Hadrup, Niels; Skov, Kasper; Taxvig, Camilla;

    2013-01-01

    Purpose: When mathematical models are applied for assessment of chemical mixture effects, assumptions of lack of synergy or potentiation have to be made; Thus joint effects of chemicals are anticipated not to be unexpectedly high. The present investigation was designed to test whether a chemical...... mixture at human relevant doses interacts with perfluorononanoic acid (PFNA) by synergy or potentiation. Methods: Male rats were given PFNA at 0.0125, 0.25 or 5 mg/kg bw/day for 14 days with or without a mixture containing 12 endocrine disrupters (total dose 2.5 mg/kg bw/day), bergamottin from grapefruit...... on testes enzyme mRNA levels. These effects were similar both with and without mixture. In contrast, co-treatment with mixture increased both relative and absolute liver weights of the 5 mg/kg/day PFNA, suggesting that liver toxicity was exacerbated by the mixture. These data suggest that a chemical...

  9. International issues on human health effects of exposure to chemical mixtures.

    OpenAIRE

    Feron, Victor J; Cassee, Flemming R; Groten, John P.; van Vliet, Petronella W; van Zorge, Job A

    2002-01-01

    In this article, we highlight new developments and recent studies concerning adverse human health effects related to chemical mixtures. One group of activities comprises the development of a new computer program for analyzing mixture studies and a mathematical model as a basis for combination rules that predict the toxicity of mixtures. Other new activities in the area of experimental studies are the application of gene expression technologies in mixture research, and pattern recognition as a...

  10. 76 FR 41365 - Impact of Reducing the Mixture Concentration Threshold for Commercial Schedule 2A Chemical...

    Science.gov (United States)

    2011-07-13

    ... Regulations (CWCR) to reduce the concentration level below which the CWCR exempt certain mixtures containing a... threshold. Legislative amendment of the Chemical Weapons Convention Implementation Act (CWCIA) is required... Impact of Reducing the Mixture Concentration Threshold for Commercial Schedule 2A Chemical...

  11. Physiological modeling and extrapolation of pharmacokinetic interactions from binary to more complex chemical mixtures.

    Science.gov (United States)

    Krishnan, Kannan; Haddad, Sami; Béliveau, Martin; Tardif, Robert

    2002-12-01

    The available data on binary interactions are yet to be considered within the context of mixture risk assessment because of our inability to predict the effect of a third or a fourth chemical in the mixture on the interacting binary pairs. Physiologically based pharmacokinetic (PBPK) models represent a potentially useful framework for predicting the consequences of interactions in mixtures of increasing complexity. This article highlights the conceptual basis and validity of PBPK models for extrapolating the occurrence and magnitude of interactions from binary to more complex chemical mixtures. The methodology involves the development of PBPK models for all mixture components and interconnecting them at the level of the tissue where the interaction is occurring. Once all component models are interconnected at the binary level, the PBPK framework simulates the kinetics of all mixture components, accounting for the interactions occurring at various levels in more complex mixtures. This aspect was validated by comparing the simulations of a binary interaction-based PBPK model with experimental data on the inhalation kinetics of m-xylene, toluene, ethyl benzene, dichloromethane, and benzene in mixtures of varying composition and complexity. The ability to predict the kinetics of chemicals in complex mixtures by accounting for binary interactions alone within a PBPK model is a significant step toward the development of interaction-based risk assessment for chemical mixtures. PMID:12634130

  12. Performance Characteristic of Cold Recycled Mixture with Asphalt Emulsion and Chemical Additives

    Directory of Open Access Journals (Sweden)

    Shaowen Du

    2015-01-01

    Full Text Available Three types of chemical additives were used to modify asphalt emulsion recycled mixture. These chemical additives include composite Portland cement (CPC, hydrated lime (HL, and a combination of hydrated lime and ground-granulated blast-furnace slag (GGBF. The influence of different additives on the recycled mixture performance was investigated by volumetric and strength tests, moisture susceptibility test, rutting resistance test, and low temperature bending test. To better understand its performance characteristic, the microstructure images of the recycled mixture were observed by environmental scanning electron microscope (ESEM. Test results demonstrate that the performance improvement of the emulsion recycled mixture depends on the types and content of chemical additives. Several recommendations are presented for the selection of chemical materials. Based on ESEM image analysis, the interface bonding mechanism is proposed to explain the performance characteristic of the recycled mixture with asphalt emulsion and cementitious materials.

  13. 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.

  14. A Chemical Properties Simulator to Support Integrated Environmental Modeling (proceeding)

    Science.gov (United States)

    Users of Integrated Environmental Modeling (IEM) systems are responsible for defining individual chemicals and their properties, a process that is time-consuming at best and overwhelming at worst, especially for new chemicals with new structures. A software tool is needed to allo...

  15. Proceedings of national symposium on innovative strategies for cost competitiveness in Indian chemical industry

    International Nuclear Information System (INIS)

    The proceedings are structured in such a manner to cover all the facets of the chemical industry and the cost competitiveness. The topics covered also include membrane technology, nuclear desalination, heavy water production and other topics connected with nuclear industry. Papers relevant to INIS are indexed separately

  16. Measurement and chemical kinetic model predictions of detonation cell size in methanol-oxygen mixtures

    Science.gov (United States)

    Eaton, R.; Zhang, B.; Bergthorson, J. M.; Ng, H. D.

    2012-03-01

    In this study, detonation cell sizes of methanol-oxygen mixtures are experimentally measured at different initial pressures and compositions. Good agreement is found between the experiment data and predictions based on the chemical length scales obtained from a detailed chemical kinetic model. To assess the detonation sensitivity in methanol-oxygen mixtures, the results are compared with those of hydrogen-oxygen and methane-oxygen mixtures. Based on the cell size comparison, it is shown that methanol-oxygen is more detonation sensitive than methane-oxygen but less sensitive than hydrogen-oxygen.

  17. 75 FR 37301 - Exempt Chemical Mixtures Containing Gamma-Butyrolactone

    Science.gov (United States)

    2010-06-29

    ...-Rape Drug Prohibition Act of 2000, on February 18, 2000. GBL and GHB induce a sense of euphoria and... intended for human consumption (21 U.S.C. 813). The analogue provision of the CSA has been applied to prosecute individuals who have diverted GBL for human consumption. Although a chemical commodity when...

  18. Extrudates of starch-xanthan gum mixtures as affected by chemical agents and irradiation

    International Nuclear Information System (INIS)

    Mixtures of starch, xanthan gum and either polyvinyl alcohol, epichlorohydrin, valeric acid or adipoyl chloride were extruded. Properties of extrudates including apparent viscosity, water solubility, water absorption indices and extrudate expansion were measured for different proportions of xanthan gum, 70% amylose starch (with or without irradiation) and chemical agents. Extrusion with chemical agents and irradiation changed physical properties of both starch and xanthan gum. Expansions of extrudates were higher than that of starch. Viscosity of extrudates increased with xanthan gum concentration. The addition of 1% (w/w) polyvinyl alcohol had the greatest effect of the chemical agents. Irradiation increased the apparent viscosity of starch-xanthan gum mixtures

  19. Proceedings

    International Nuclear Information System (INIS)

    These 1974 Proceedings of the European Society of Nuclear Methods in Agriculture contain reports in the form of minutes of the meetings of various working groups of the Society, the programme and official addresses of the fifth annual meeting including annual reports of the chairman and the secretary of the Society, and the reports of each of the eleven working groups as well as the four following surveys entitled: 1) some aspects of research in plant breeding, conservation of genetic resources in connection with irradiation processes (by A. Jacques from FAO), 2) our responsibility for the environment (by D. Zeeuw from ITAL), 3) pilot plant for the irradiation of sewage sludge (by A. Suesz from Bayerische Landesanstalt fuer Bodenkultur und Pflanzenbau, Munich), 4) nuclear agronomy in France (by P. Guerin de Montgareuil from CEN, Cadarache). Summaries and provisional papers on presented topics will be published in ''ESNA Newsletter''

  20. The underlying toxicological mechanism of chemical mixtures: A case study on mixture toxicity of cyanogenic toxicants and aldehydes to Photobacterium phosphoreum

    Energy Technology Data Exchange (ETDEWEB)

    Tian, Dayong [State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092 (China); Department of Chemical and Environmental Engineering, Anyang Institute of Technology, Anyang 455000 (China); Lin, Zhifen, E-mail: lzhifen@tongji.edu.cn [State Key Laboratory of Pollution Control and Resource Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092 (China); Zhou, Xianghong [Department of Public Management, Tongji University, Shanghai 200092 (China); Yin, Daqiang [Key Laboratory of Yangtze River Water Environment, Ministry of Education, College of Environmental Science and Engineering, Tongji University, Shanghai 200092 (China)

    2013-10-15

    Intracellular chemical reaction of chemical mixtures is one of the main reasons that cause synergistic or antagonistic effects. However, it still remains unclear what the influencing factors on the intracellular chemical reaction are, and how they influence on the toxicological mechanism of chemical mixtures. To reveal this underlying toxicological mechanism of chemical mixtures, a case study on mixture toxicity of cyanogenic toxicants and aldehydes to Photobacterium phosphoreum was employed, and both their joint effects and mixture toxicity were observed. Then series of two-step linear regressions were performed to describe the relationships between joint effects, the expected additive toxicities and descriptors of individual chemicals (including concentrations, binding affinity to receptors, octanol/water partition coefficients). Based on the quantitative relationships, the underlying joint toxicological mechanisms were revealed. The result shows that, for mixtures with their joint effects resulting from intracellular chemical reaction, their underlying toxicological mechanism depends on not only their interaction with target proteins, but also their transmembrane actions and their concentrations. In addition, two generic points of toxicological mechanism were proposed including the influencing factors on intracellular chemical reaction and the difference of the toxicological mechanism between single reactive chemicals and their mixtures. This study provided an insight into the understanding of the underlying toxicological mechanism for chemical mixtures with intracellular chemical reaction. - Highlights: • Joint effects of nitriles and aldehydes at non-equitoxic ratios were determined. • A novel descriptor, ligand–receptor interaction energy (E{sub binding}), was employed. • Quantitative relationships for mixtures were developed based on a novel descriptor. • The underlying toxic mechanism was revealed based on quantitative relationships. • Two

  1. Chemical mixtures: Evaluation of risk for child-specific exposures in a multi-stressor environment

    International Nuclear Information System (INIS)

    Evaluating the health impact from exposure to chemical mixtures is multifaceted. One component is exposure. Exposure, and consequently risk assessment for mixtures and chemicals in general, are often viewed in terms of a given exposure to a given population at a given location over a given time period. However, environmental exposures are present throughout human lifetime. As a result, an evaluation of risk must include the distinctive characteristics related to chemical exposures which will impact risk depending upon the particular life stage where exposure occurs. Risks to offspring may be associated with unique exposures in utero, during infancy, childhood, or adolescent periods. For example, exposure of infants to anthropogenic chemicals via breast milk may be of concern. The Agency for Toxic Substances and Disease Registry's (ATSDR's) approach to evaluating risks associated with exposure to mixtures of chemicals is presented. In addition to the breast milk issues, indoor exposure to combined air pollutants, drinking water contaminants, and soil and dust contaminants are discussed. The difference between a mixture's risk evaluation for children and adults is in the distinct exposure scenarios resulting from variations in behavior, physiology, and/or pharmacokinetics between adults and children rather than in the method for the specific mixtures evaluation per se

  2. Modelling of associating mixtures for applications in the oil & gas and chemical industries

    DEFF Research Database (Denmark)

    Kontogeorgis, Georgios; Folas, Georgios; Muro Sunè, Nuria;

    2007-01-01

    Thermodynamic properties and phase equilibria of associating mixtures cannot often be satisfactorily modelled using conventional models such as cubic equations of state. CPA (cubic-plus-association) is an equation of state (EoS), which combines the SRK EoS with the association term of SAFT. For non......-polar (non self-associating) compounds it reduces to SRK. The model was first published in 1996 and since then it has been developed and applied with success to binary systems containing water-alkanes and alcohol/glycol/acid-alkanes (both VLE and LLE) as well as ternary and multicomponent (V)LLE for water...... of the model of relevance to the petroleum and chemical industries: high pressure vapor-liquid and liquid-liquid equilibrium in alcohol-containing mixtures, mixtures with gas hydrate inhibitors and mixtures with polar and hydrogen bonding chemicals including organic acids. Some comparisons with conventional...

  3. Perinatal exposure to mixtures of anti-androgenic chemicals causes proliferative lesions in rat prostate

    DEFF Research Database (Denmark)

    Boberg, Julie; Johansson, Hanna Katarina Lilith; Hadrup, Niels;

    2015-01-01

    BACKGROUND: Elevated levels of endogenous or exogenous estrogens during fetal life can induce permanent disturbances in prostate growth and predispose to precancerous lesions. Recent studies have indicated that also early anti-androgen exposure may affect prostate cancer risk. METHODS: We examined...... the influence of perinatal exposure to mixtures of anti-androgenic and estrogenic chemicals on prostate development. Wistar rats were exposed from gestation day 7 to postnatal day 22 to a mixture of 8 anti-androgenic compounds (AAMix), a mixture of four estrogenic compounds (EMix), or paracetamol or a...

  4. Chemical contaminants on DOE lands and selection of contaminant mixtures for subsurface science research

    Energy Technology Data Exchange (ETDEWEB)

    Riley, R.G.; Zachara, J.M. [Pacific Northwest Lab., Richland, WA (United States)

    1992-04-01

    This report identifies individual contaminants and contaminant mixtures that have been measured in the ground at 91 waste sites at 18 US Department of Energy (DOE) facilities within the weapons complex. The inventory of chemicals and mixtures was used to identify generic chemical mixtures to be used by DOE`s Subsurface Science Program in basic research on the subsurface geochemical and microbiological behavior of mixed contaminants (DOE 1990a and b). The generic mixtures contain specific radionuclides, metals, organic ligands, organic solvents, fuel hydrocarbons, and polychlorinated biphenyls (PCBs) in various binary and ternary combinations. The mixtures are representative of in-ground contaminant associations at DOE facilities that are likely to exhibit complex geochemical behavior as a result of intercontaminant reactions and/or microbiologic activity stimulated by organic substances. Use of the generic mixtures will focus research on important mixed contaminants that are likely to be long-term problems at DOE sites and that will require cleanup or remediation. The report provides information on the frequency of associations among different chemicals and compound classes at DOE waste sites that require remediation.

  5. Chemical contaminants on DOE lands and selection of contaminant mixtures for subsurface science research

    Energy Technology Data Exchange (ETDEWEB)

    Riley, R.G.; Zachara, J.M. (Pacific Northwest Lab., Richland, WA (United States))

    1992-04-01

    This report identifies individual contaminants and contaminant mixtures that have been measured in the ground at 91 waste sites at 18 US Department of Energy (DOE) facilities within the weapons complex. The inventory of chemicals and mixtures was used to identify generic chemical mixtures to be used by DOE's Subsurface Science Program in basic research on the subsurface geochemical and microbiological behavior of mixed contaminants (DOE 1990a and b). The generic mixtures contain specific radionuclides, metals, organic ligands, organic solvents, fuel hydrocarbons, and polychlorinated biphenyls (PCBs) in various binary and ternary combinations. The mixtures are representative of in-ground contaminant associations at DOE facilities that are likely to exhibit complex geochemical behavior as a result of intercontaminant reactions and/or microbiologic activity stimulated by organic substances. Use of the generic mixtures will focus research on important mixed contaminants that are likely to be long-term problems at DOE sites and that will require cleanup or remediation. The report provides information on the frequency of associations among different chemicals and compound classes at DOE waste sites that require remediation.

  6. Should the scope of human mixture risk assessment span legislative/regulatory silos for chemicals?

    Science.gov (United States)

    Evans, Richard M; Martin, Olwenn V; Faust, Michael; Kortenkamp, Andreas

    2016-02-01

    Current chemicals regulation operates almost exclusively on a chemical-by-chemical basis, however there is concern that this approach may not be sufficiently protective if two or more chemicals have the same toxic effect. Humans are indisputably exposed to more than one chemical at a time, for example to the multiple chemicals found in food, air and drinking water, and in household and consumer products, and in cosmetics. Assessment of cumulative risk to human health and/or the environment from multiple chemicals and routes can be done in a mixture risk assessment (MRA). Whilst there is a broad consensus on the basic science of mixture toxicology, the path to regulatory implementation of MRA within chemical risk assessment is less clear. In this discussion piece we pose an open question: should the scope of human MRA cross legislative remits or 'silos'? We define silos as, for instance, legislation that defines risk assessment practice for a subset of chemicals, usually on the basis of substance/product, media or process orientation. Currently any form of legal mandate for human MRA in the EU is limited to only a few pieces of legislation. We describe two lines of evidence, illustrated with selected examples, that are particularly pertinent to this question: 1) evidence that mixture effects have been shown for chemicals regulated in different silos and 2) evidence that humans are co-exposed to chemicals from different silos. We substantiate the position that, because there is no reason why chemicals allocated to specific regulatory silos would have non-overlapping risk profiles, then there is also no reason to expect that MRA limited only to chemicals within one silo can fully capture the risk that may be present to human consumers. Finally, we discuss possible options for implementation of MRA and we hope to prompt wider discussion of this issue. PMID:26573369

  7. Initial analyses of the relationship between 'Thresholds' of toxicity for individual chemicals and 'Interaction Thresholds' for chemical mixtures

    International Nuclear Information System (INIS)

    The inter-relationship of 'Thresholds' between chemical mixtures and their respective component single chemicals was studied using three sets of data and two types of analyses. Two in vitro data sets involve cytotoxicity in human keratinocytes from treatment of metals and a metal mixture [Bae, D.S., Gennings, C., Carter, Jr., W.H., Yang, R.S.H., Campain, J.A., 2001. Toxicological interactions among arsenic, cadmium, chromium, and lead in human keratinocytes. Toxicol. Sci. 63, 132-142; Gennings, C., Carter, Jr., W.H., Campain, J.A., Bae, D.S., Yang, R.S.H., 2002. Statistical analysis of interactive cytotoxicity in human epidermal keratinocytes following exposure to a mixture of four metals. J. Agric. Biol. Environ. Stat. 7, 58-73], and induction of estrogen receptor alpha (ER-α) reporter gene in MCF-7 human breast cancer cells by estrogenic xenobiotics [Gennings, C., Carter, Jr., W.H., Carney, E.W., Charles, G.D., Gollapudi, B.B., Carchman, R.A., 2004. A novel flexible approach for evaluating fixed ratio mixtures of full and partial agonists. Toxicol. Sci. 80, 134-150]. The third data set came from PBPK modeling of gasoline and its components in the human. For in vitro cellular responses, we employed Benchmark Dose Software (BMDS) to obtain BMD01, BMD05, and BMD10. We then plotted these BMDs against exposure concentrations for the chemical mixture and its components to assess the ranges and slopes of these BMD-concentration lines. In doing so, we consider certain BMDs to be 'Interaction Thresholds' or 'Thresholds' for mixtures and their component single chemicals and the slope of the line must be a reflection of the potency of the biological effects. For in vivo PBPK modeling, we used 0.1x TLVs, TLVs, and 10x TLVs for gasoline and six component markers as input dosing for PBPK modeling. In this case, the venous blood levels under the hypothetical exposure conditions become our designated 'Interaction Thresholds' or 'Thresholds' for gasoline and its component single

  8. Disentangling the developmental and neurobehavioural effects of perinatal exposure to a chemical mixture found in blood of Arctic populations: differential toxicity of mixture components

    Energy Technology Data Exchange (ETDEWEB)

    Bowers, W.; Nakai, J.; Yagminas, A.; Chu, I.; Moir, D. [Health Canada (Canada)

    2004-09-15

    The current study was designed to evaluate the neurobehavioral effects of perinatal exposure to a chemical mixture that is based on relative concentrations of persistent organic pollutants found in the blood of Canadian Arctic populations and contains 14 PCB congeners, 12 organochlorine pesticides and methyl mercury. This study compared the effects of the complete mixture with the effects of three major components of the mixture (the PCB component, the organochlorine pesticide component, and the methyl mercury component). By examining a range of neurobehavioural functions over development we also determine if specific neurobehavioural disturbances produced by the mixture can be attributed to components of the mixture and if neurobehavioural effects produced by components of the mixture are altered by concurrent exposure to other components in the mixture. Ninety-two nulliparious female Sprague-Dawley rats served as subjects.

  9. Data set from chemical sensor array exposed to turbulent gas mixtures

    OpenAIRE

    Jordi Fonollosa; Irene Rodríguez-Luján; Marco Trincavelli; Ramón Huerta

    2015-01-01

    A chemical detection platform composed of 8 chemo-resistive gas sensors was exposed to turbulent gas mixtures generated naturally in a wind tunnel. The acquired time series of the sensors are provided. The experimental setup was designed to test gas sensors in realistic environments. Traditionally, chemical detection systems based on chemo-resistive sensors include a gas chamber to control the sample air flow and minimize turbulence. Instead, we utilized a wind tunnel with two independent gas...

  10. Surface enhanced Raman spectroscopy detection of trace chemicals in inhomogeneous fluid mixtures

    OpenAIRE

    Tiainen, Laura

    2015-01-01

    Detecting trace chemicals in heterogeneous fluid mixtures has a variety of possible applications for example in food industry. The drivers of this development have not only been build on consumer awareness but have also been emphasized by decision makers at the EU level. The current laboratory methods are laborious, expensive and slow, which challenges their application in milk quality control especially in terms of qualitatively detecting such chemical residues an melamine. More studied are ...

  11. Mixtures of environmentally relevant endocrine disrupting chemicals affect mammary gland development in female and male rats

    DEFF Research Database (Denmark)

    Mandrup, Karen Riiber; Johansson, Hanna Katarina Lilith; Boberg, Julie; Pedersen, Anne S.; Mortensen, Mette Sidsel; Jørgensen, Jennifer Solgaard; Vinggaard, Anne Marie; Hass, Ulla

    2015-01-01

    Estrogenic chemicals are able to alter mammary gland development in female rodents, but little is known on the effects of anti-androgens and mixtures of endocrine disrupting chemicals (EDCs) with dissimilar modes of action. Pregnant rat dams were exposed during gestation and lactation to mixtures...... of environmentally relevant EDCs with estrogenic, anti-androgenic or dissimilar modes of action (TotalMix) of 100-, 200- or 450-fold high end human intake estimates. Mammary glands of prepubertal and adult female and male offspring were examined. Oestrogens increased mammary outgrowth in prepubertal...... females and the mRNA level of matrix metalloproteinase-3, which may be a potential biomarker for increased outgrowth. Mixtures of EDCs gave rise to ductal hyperplasia in adult males. Adult female mammary glands of the TotalMix group showed morphological changes possibly reflecting increased prolactin...

  12. Sedimentation stacking diagram of binary colloidal mixtures and bulk phases in the plane of chemical potentials

    Science.gov (United States)

    de las Heras, Daniel; Schmidt, Matthias

    2015-05-01

    We give a full account of a recently proposed theory that explicitly relates the bulk phase diagram of a binary colloidal mixture to its phase stacking phenomenology under gravity (de las Heras and Schmidt 2013 Soft Matter 9 8636). As we demonstrate, the full set of possible phase stacking sequences in sedimentation-diffusion equilibrium originates from straight lines (sedimentation paths) in the chemical potential representation of the bulk phase diagram. From the analysis of various standard topologies of bulk phase diagrams, we conclude that the corresponding sedimentation stacking diagrams can be very rich, even more so when finite sample height is taken into account. We apply the theory to obtain the stacking diagram of a mixture of nonadsorbing polymers and colloids. We also present a catalog of generic phase diagrams in the plane of chemical potentials in order to facilitate the practical application of our concept, which also generalizes to multi-component mixtures.

  13. Combined physical and chemical absorption of carbon dioxide in a mixture of ionic liquids

    International Nuclear Information System (INIS)

    Highlights: • Carbon dioxide can be absorbed in mixtures of two ionic liquids: [C2mim][EtSO4] and [C2mim][OAc]. • A combination of physical and chemical absorption mechanisms is observed. • The CO2 absorption capacity of the mixture of ionic liquids decreases with increasing temperature. • [C2mim][EtSO4] in the mixture prevents solidification of the product resulting from reaction of [C2mim][OAc] and CO2. • Density and viscosity studies of the mixture of ionic liquids also lead to synergies, in particular at low temperatures. - Abstract: Ionic liquids have attracted great interest recently as the basis of a potential alternative technology for the capture of carbon dioxide. Beyond the inherent tunability of properties of individual ionic liquids, a further strategy in optimising the ionic liquid sorbent for this application is the use of mixtures of ‘pure’ ionic liquids. Some ionic liquids absorb CO2 physically, whereas others do so chemically. Both mechanisms of absorption present advantages and disadvantages for a CO2 capture process operating in a continuous regime. In this work, a mixture of 1-ethyl-3-methylimidazolium acetate (an ionic liquid that reacts chemically with CO2) and 1-ethyl-3-methylimidazolium ethylsulfate (an ionic liquid that absorbs CO2 only through a physical mechanism) was investigated for the absorption of CO2 as a function of temperature and at pressures up to 17 bar. The absorption/desorption studies were complemented by the characterisation of thermal and physical properties of the mixture of ionic liquids, which provide extra information on the interactions at a molecular level, and are also critical for the assessment of its suitability for a proposed process and for the subsequent process design

  14. AGONISTIC SENSORY EFFECTS OF AIRBORNE CHEMICALS IN MIXTURES: ODOR, NASAL PUNGENCY, AND EYE IRRITATION

    Science.gov (United States)

    Threshold responses of odor, nasal pungency (irritation), and eye irritation were measured for single chemicals (1-propanol, 1-hexanol, ethyl acetate, heptyl acetate, 2-pentanone, 2-heptanone, toluene, ethyl benzene, and propyl benzene) and mixtures of them (two three-component m...

  15. Data set from chemical sensor array exposed to turbulent gas mixtures.

    Science.gov (United States)

    Fonollosa, Jordi; Rodríguez-Luján, Irene; Trincavelli, Marco; Huerta, Ramón

    2015-06-01

    A chemical detection platform composed of 8 chemo-resistive gas sensors was exposed to turbulent gas mixtures generated naturally in a wind tunnel. The acquired time series of the sensors are provided. The experimental setup was designed to test gas sensors in realistic environments. Traditionally, chemical detection systems based on chemo-resistive sensors include a gas chamber to control the sample air flow and minimize turbulence. Instead, we utilized a wind tunnel with two independent gas sources that generate two gas plumes. The plumes get naturally mixed along a turbulent flow and reproduce the gas concentration fluctuations observed in natural environments. Hence, the gas sensors can capture the spatio-temporal information contained in the gas plumes. The sensor array was exposed to binary mixtures of ethylene with either methane or carbon monoxide. Volatiles were released at four different rates to induce different concentration levels in the vicinity of the sensor array. Each configuration was repeated 6 times, for a total of 180 measurements. The data is related to "Chemical Discrimination in Turbulent Gas Mixtures with MOX Sensors Validated by Gas Chromatography-Mass Spectrometry", by Fonollosa et al. [1]. The dataset can be accessed publicly at the UCI repository upon citation of [1]: http://archive.ics.uci.edu/ml/datasets/Gas+senso+rarray+exposed+to+turbulent+gas+mixtures. PMID:26217747

  16. Physical-chemical characteristics of an eco-friendly binder using ternary mixture of industrial wastes

    OpenAIRE

    Nguyen, Hoang-Anh; Chang, Ta-Peng; Chen, Chun-Tao; Yang, Tzong-Ruey; Nguyen, Tien-Dung

    2015-01-01

    This study explores the physical-chemical characteristics of paste and mortar with an eco-friendly binder named as SFC cement, produced by a ternary mixture of industrial waste materials of ground granulated blast furnace slag (S), Class F fly ash (FFA), and circulating fluidized bed combustion fly ash (CFA). To trigger the hydration, the CFA, which acted as an alkaline-sulfate activator, was added to the blended mixture of slag and FFA. The water to binder ratio (W/B), curing regime, and FFA...

  17. Enhancing the Benefit of the Chemical Mixture Methodology: A Report on Methodology Testing and Potential Approaches for Improving Performance

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Xiao-Ying; Yao, Juan; He, Hua; Glantz, Clifford S.; Booth, Alexander E.

    2012-01-01

    Extensive testing shows that the current version of the Chemical Mixture Methodology (CMM) is meeting its intended mission to provide conservative estimates of the health effects from exposure to airborne chemical mixtures. However, the current version of the CMM could benefit from several enhancements that are designed to improve its application of Health Code Numbers (HCNs) and employ weighting factors to reduce over conservatism.

  18. Characterization of Dimethylsulfoxide / Glycerol Mixtures: A Binary Solvent System for the Study of "Friction-Dependent" Chemical Reactivity

    OpenAIRE

    Angulo Nunez, Gonzalo Manuel; Brucka, Marta; Gerecke, Mario; Grampp, Günter; Jeannerat, Damien; Milkiewicz, Jadwiga; Mitrev, Yavor; Radzewicz, Czesław; Rosspeintner, Arnulf; Vauthey, Eric; Wnuk, Paweł

    2016-01-01

    The properties of binary mixtures of dimethylsulfoxide and glycerol, measured by several techniques, are reported. Special attention is given to those properties contributing or affecting chemical reactions. In this respect the investigated mixture behaves as a relatively simple solvent and it is especially well suited for studies on the influence of viscosity in chemical reactivity. This is due to the relative invariance of the dielectric properties of the mixture. However, special caution m...

  19. Solid State and Chemical Radiation Dosimetry in Medicine and Biology. Proceedings of a Symposium

    International Nuclear Information System (INIS)

    Proceedings of a Symposium organized by the IAEA and held in Vienna, 3-7 October 1966. The meeting was attended by 104 participants from 21 countries and three international organizations. Contents: Solid state dosimetry (17 papers); Chemical dosimetry (10 papers); Invited lectures (2 papers); General aspects and other methods of dosimetry (6 papers); Panel discussion on research and development needed in dosimetry. Each paper is in its original language (32 English, 2 French and 1 Spanish) and is preceded by an abstract in English and one in the original language, if this is not English. Discussions are in English. (author)

  20. The Effect of Perfluorooctane Sulfonate, Exposure Time, and Chemical Mixtures on Methanogenic Community Structure and Function.

    Science.gov (United States)

    McNamara, Patrick J; LaPara, Timothy M; Novak, Paige J

    2015-01-01

    A plethora of organic micropollutant mixtures are found in untreated municipal wastewater. Anaerobic digesters receive large loadings of hydrophobic micropollutants that sorb to wastewater biosolids. Despite micropollutants being pervasive as mixtures, little research is available to explain the impact that mixtures of compounds, as well as exposure time, have on microbial communities in anaerobic digesters. Perfluorooctane sulfonate (PFOS) was added to anaerobic enrichment cultures in both short-term (14 days) and long-term (140 days) studies to determine the impact of exposure time. Additionally, triclosan was added during the experiments to investigate the impact of mixtures on community structure and function. PFOS did not alter methane production in short-term studies, but in long-term studies, methane production increased, consistent with our hypothesis that PFOS may act as a metabolic uncoupler. The impact of triclosan on methane production was exacerbated when PFOS was already present in the anaerobic enrichment cultures. Triclosan also had greater impacts on microbial community structures in the bottles that had been exposed to PFOS long-term. These results demonstrate that both chemical mixtures and exposure time are important parameters to address when trying to define the impacts of micropollutants on anaerobic microbial communities. PMID:26462249

  1. The Effect of Perfluorooctane Sulfonate, Exposure Time, and Chemical Mixtures on Methanogenic Community Structure and Function

    Science.gov (United States)

    McNamara, Patrick J; LaPara, Timothy M; Novak, Paige J

    2015-01-01

    A plethora of organic micropollutant mixtures are found in untreated municipal wastewater. Anaerobic digesters receive large loadings of hydrophobic micropollutants that sorb to wastewater biosolids. Despite micropollutants being pervasive as mixtures, little research is available to explain the impact that mixtures of compounds, as well as exposure time, have on microbial communities in anaerobic digesters. Perfluorooctane sulfonate (PFOS) was added to anaerobic enrichment cultures in both short-term (14 days) and long-term (140 days) studies to determine the impact of exposure time. Additionally, triclosan was added during the experiments to investigate the impact of mixtures on community structure and function. PFOS did not alter methane production in short-term studies, but in long-term studies, methane production increased, consistent with our hypothesis that PFOS may act as a metabolic uncoupler. The impact of triclosan on methane production was exacerbated when PFOS was already present in the anaerobic enrichment cultures. Triclosan also had greater impacts on microbial community structures in the bottles that had been exposed to PFOS long-term. These results demonstrate that both chemical mixtures and exposure time are important parameters to address when trying to define the impacts of micropollutants on anaerobic microbial communities. PMID:26462249

  2. Human toxicology of chemical mixtures toxic consequences beyond the impact of one-component product and environmental exposures

    CERN Document Server

    Zeliger, Harold I

    2011-01-01

    In this important reference work, Zeliger catalogs the known effects of chemical mixtures on the human body and also proposes a framework for understanding and predicting their actions in terms of lipophile (fat soluble)/hydrophile (water soluble) interactions. The author's focus is on illnesses that ensue following exposures to mixtures of chemicals that cannot be attributed to any one component of the mixture. In the first part the mechanisms of chemical absorption at a molecular and macromolecular level are explained, as well as the body's methods of defending itself against xenobiotic intrusion. Part II examines the sources of the chemicals discussed, looking at air and water pollution, food additives, pharmaceuticals, etc. Part III, which includes numerous case studies, examines specific effects of particular mixtures on particular body systems and organs and presents a theoretical framework for predicting what the effects of uncharacterized mixtures might be. Part IV covers regulatory requirements and t...

  3. Electron behaviour in CH4/H2 gas mixture in electron-assisted chemical vapour deposition

    Institute of Scientific and Technical Information of China (English)

    Dong Li-Fang; Ma Bo-Qin; Wang Zhi-Jun

    2004-01-01

    The behaviour of electrons in CH4/H2 gas mixture in electron-assisted chemical vapour deposition of diamond is investigated using Monte Carlo simulation. The electron drift velocity in gas mixture is obtained over a wide range of E/P (the ratio of the electric field to gas pressure) from 1500 to 300000 (V/m kPa-1). The electron energy distribution and average energy under different gas pressure (0.1-20kPa) and CH4 concentration (0.5%-10.0%) are calculated. Their effects on the diamond growth are also discussed. It is believed that these results will be helpful to the selection of optimum experimental conditions for high quality diamond film deposition.

  4. Joint effects of a mixture of 14 chemicals on mortality and inhibition of reproduction of Daphnia magna

    NARCIS (Netherlands)

    Hermens, J.L.M.; Canton, H.; Steyger, N.; Wegman, R.

    1984-01-01

    The toxicity to Daphnia magna of a mixture of 14 aquatic pollutants with several chemical structures and probable modes of action was determined. The joint effect of this mixture on acute mortality was compared with the effects on inhibition of reproduction. The joint toxicity in the reproduction te

  5. Summer 2012 Testing and Analysis of the Chemical Mixture Methodology -- Part I

    Energy Technology Data Exchange (ETDEWEB)

    Glantz, Clifford S.; Yu, Xiao-Ying; Coggin, Rebekah L.; Ponder, Lashaundra A.; Booth, Alexander E.; Petrocchi, Achille J.; Horn, Sarah M.; Yao, Juan

    2012-07-01

    This report presents the key findings made by the Chemical Mixture Methodology (CMM) project team during the first stage of their summer 2012 testing and analysis of the CMM. The study focused on answering the following questions: o What is the percentage of the chemicals in the CMM Rev 27 database associated with each Health Code Number (HCN)? How does this result influence the relative importance of acute HCNs and chronic HCNs in the CMM data set? o What is the benefit of using the HCN-based approach? Which Modes of Action and Target Organ Effects tend to be important in determining the HCN-based Hazard Index (HI) for a chemical mixture? o What are some of the potential issues associated with the current HCN-based approach? What are the opportunities for improving the performance and/or technical defensibility of the HCN-based approach? How would those improvements increase the benefit of using the HCN-based approach? o What is the Target Organ System Effect approach and how can it be used to improve upon the current HCN-based approach? How does the benefits users would derive from using the Target Organ System Approach compare to the benefits available from the current HCN-based approach?

  6. Electrochemical study of chemical properties in ethanolamine and its mixtures with water

    International Nuclear Information System (INIS)

    This work is concerned with the study of acid-base reactions and of complex formation in ethanolamine and its mixtures with water. The ionic product of the solvent has been determined by an electro-chemical study of the H+/H2 system. The reduction curves for ethanolamine-water mixtures, for different acidities, have made it possible to follow the variations in the size of the pH domain as a function of the composition of the solvent. The form of this variation has been explained on the basis of the dielectric constant and the solvation of the proton by the ethanolamine. In the second part, the electrochemical systems of mercury have been studied by anodic polarography. In order to establish a parallel between the acid-base reactions and complex formation reactions, we have studied the stability of Hg (CN)2 in water-ethanolamine mixtures. It has been possible to deduce the law for the variation of pKc with solvent composition. The representative graph of this function passes through a minimum for a proportion of about 50 per cent of ethanolamine as in the case of acids. This variation has been explained by the predominating influence of ε for ethanolamine propositions of over 50 per cent and by that of the solvation of Hg2+ for proportions of under 50 per cent. (author)

  7. Phase transition and chemical decomposition of liquid carbon dioxide and nitrogen mixture under extreme conditions

    Science.gov (United States)

    Xiao-Xu, Jiang; Guan-Yu, Chen; Yu-Tong, Li; Xin-Lu, Cheng; Cui-Ming, Tang

    2016-02-01

    Thermodynamic and chemical properties of liquid carbon dioxide and nitrogen (CO2-N2) mixture under the conditions of extremely high densities and temperatures are studied by using quantum molecular dynamic (QMD) simulations based on density functional theory including dispersion corrections (DFT-D). We present equilibrium properties of liquid mixture for 112 separate density and temperature points, by selecting densities ranging from ρ = 1.80 g/cm3 to 3.40 g/cm3 and temperatures from T = 500 K to 8000 K. In the range of our study, the liquid CO2-N2 mixture undergoes a continuous transition from molecular to atomic fluid state and liquid polymerization inferred from pair correlation functions (PCFs) and the distribution of various molecular components. The insulator-metal transition is demonstrated by means of the electronic density of states (DOS). Project supported by the National Natural Science Foundation of China (Grant Nos. 11374217, 11135012, and 11375262) and the Joint Fund of the National Natural Science Foundation of China and the China Academy of Engineering Physics (Grant No. 11176020).

  8. Characterization of Dimethylsulfoxide / Glycerol Mixtures: A Binary Solvent System for the Study of "Friction-Dependent" Chemical Reactivity

    CERN Document Server

    Angulo, Gonzalo; Gerecke, Mario; Grampp, Günter; Jeannerat, Damien; Milkiewicz, Jadwiga; Mitrev, Yavor; Radzewicz, Czesław; Rosspeintner, Arnulf; Vauthey, Eric; Wnuk, Paweł

    2016-01-01

    The properties of binary mixtures of dimethylsulfoxide and glycerol, measured by several techniques, are reported. Special attention is given to those properties contributing or affecting chemical reactions. In this respect the investigated mixture behaves as a relatively simple solvent and it is especially well suited for studies on the influence of viscosity in chemical reactivity. This is due to the relative invariance of the dielectric properties of the mixture. However, special caution must be taken with specific solvation, as the hydrogen-bonding properties of the solvent changes with the molar fraction of glycerol.

  9. Characterization of dimethylsulfoxide/glycerol mixtures: a binary solvent system for the study of "friction-dependent" chemical reactivity.

    Science.gov (United States)

    Angulo, Gonzalo; Brucka, Marta; Gerecke, Mario; Grampp, Günter; Jeannerat, Damien; Milkiewicz, Jadwiga; Mitrev, Yavor; Radzewicz, Czesław; Rosspeintner, Arnulf; Vauthey, Eric; Wnuk, Paweł

    2016-07-21

    The properties of binary mixtures of dimethylsulfoxide and glycerol, measured using several techniques, are reported. Special attention is given to those properties contributing or affecting chemical reactions. In this respect the investigated mixture behaves as a relatively simple solvent and it is especially well suited for studies on the influence of viscosity on chemical reactivity. This is due to the relative invariance of the dielectric properties of the mixture. However, special caution must be taken with specific solvation, as the hydrogen-bonding properties of the solvent change with the molar fraction of glycerol. PMID:27339434

  10. Proceedings of the frst joint american chemical society agricultural and food chemistry division – american chemical society international chemical sciences chapter in Thailand symposium on agricultural and food chemistry

    Science.gov (United States)

    This Proceedings is a compilation of papers from contributed oral and poster presentations presented at the first joint symposium organized by the American Chemical Society Agricultural and Food Chemistry Division and the American Chemical Society International Chemical Sciences Chapter in Thailand ...

  11. Diagnostics of microwave activated novel gas mixtures for diamond chemical vapour deposition

    International Nuclear Information System (INIS)

    Microwave plasma enhanced Chemical Vapour Deposition (CVD) has been used to grow diamond films at substrate temperatures as low as 435 deg C using CO2/CH4 gas mixtures. Molecular beam mass spectrometry (MBMS) has been used to measure simultaneously the concentrations of the dominant gas phase species present during growth, for a wide range of plasma gas mixtures (0 - 80% CH4, balance CO2). The CHEMKIN computer package has also been used to simulate the experimental results in order to gain insight into the major reactions occurring within the microwave plasma. The calculated trends for all species agree well with the experimental observations. Using these data, the model for the gas phase chemistry can be reduced to just four overall reactions. Our findings suggest that CH3 radicals are likely to be the key growth species when using CO2/CH4 plasmas and provide a qualitative explanation for the observation that diamond growth occurs within a very narrow concentration window. Diamond films have also been deposited; using both 1% CH4/H2 and 51%CH4/49%CO2 gas mixtures with various levels of H2S addition (100-5000 ppm). The former gas mixture was investigated using both microwave (MW) and hot filament (HF) activation and it was found that these two deposition techniques yield very different results. For both 1% CH4/H2 and 51%CH4/49%CO2 MW activated gas mixtures, scanning electron microscopy (SEM) observations show that the crystal quality of these films reduces with increasing H2S addition. Laser Raman and four point probe measurements showed a corresponding fall in the quality and resistivity of deposited diamond films, respectively. MBMS measurements for these S containing gas mixtures revealed significant concentrations of CS2 and CS in all of the MW plasmas that yield S-doped diamond films, whereas CS was not detected in the gas phase during HF growth. This suggests that CS may be an important intermediary facilitating S incorporation into diamond. All of these

  12. 78 FR 41768 - Chemical Substances and Mixtures Used in Oil and Gas Exploration or Production; TSCA Section 21...

    Science.gov (United States)

    2013-07-11

    ... AGENCY 40 CFR Chapter I Chemical Substances and Mixtures Used in Oil and Gas Exploration or Production...(a) to require manufacturers and processors of oil and gas exploration and production (E&P) chemical... Oil and Gas Exploration or Production.'' August 4, 2011. 3. EPA, ORD. EPA's Study of...

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

    DEFF Research Database (Denmark)

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

    2013-01-01

    treatments, containing the polycyclic aromatic hydrocarbons (PAHs) naphthalene, phenanthrene, and pyrene. Springtail lethality was then linked to sum chemical activities (∑a), sum equilibrium lipid concentrations (∑Clipid eq.), and sum toxic units (∑TU). In each case, the effects of all 12 mixture treatments...... could be fitted to one sigmoidal exposure-response relationship. The effective lethal chemical activity (La50) of 0.027 was well within the expected range for baseline toxicity of 0.01-0.1. Linking the effects to the lipid-based exposure parameter yielded an effective lethal concentration (LClipid eq....... 50) of 133 mmol kg-1 lipid in good correspondence with the lethal membrane burden for baseline toxicity (40-160 mmol kg-1 lipid). Finally, the effective lethal toxic unit (LTU50) of 1.20 was rather close to the expected value of 1. Altogether, passive dosing provided tightly controlled mixture...

  14. Probabilistic Human Health Risk Assessment of Chemical Mixtures: Hydro-Toxicological Interactions and Controlling Factors

    Science.gov (United States)

    Henri, C.; Fernandez-Garcia, D.; de Barros, F.

    2014-12-01

    Improper disposals of hazardous wastes in most industrial countries give rise to severe groundwater contamination problems that can lead to adverse health effects in humans. Therefore risk assessment methods play an important role in population protection by (1) quantifying the impact on human health of an aquifer contamination and (2) aiding the decision making process of to better manage our groundwater resources. Many reactive components such as chlorinated solvent or nitrate potentially experience attenuation processes under common geochemical conditions. Based on this, monitored natural attenuation has become nowadays an attractive remediation solution. However, in some cases, intermediate degradation products can constitute noxious chemical compounds before reaching a harmless chemical form. In these cases, the joint effect of advection-dispersion transport and the species-dependent kinetic reactions and toxicity will dictate the relative importance of the degradation byproducts to the total risk. This renders the interpretation of risk a non-trivial task. In this presentation, we quantify, through a probabilistic framework, the human health risk posed by a chemical mixture in a heterogeneous aquifer. This work focuses on a Perchloroethylene contamination problem followed by the first-order production/biodegradation of its daughter species Trichloroethylene, Dichloroethylene and Vinyl Chlorine that is known to be highly toxic. Uncertainty on the hydraulic conductivity field is considered through a Monte Carlo scheme. A comparative description of human health risk metrics as a function of aquifer heterogeneity and contaminant injection mode is provided by means of a spatial characterization of the lower-order statistical moments and empirical probability density functions of both individual and total risks. Interestingly, we show that the human health risk of a chemical mixture is mainly controlled by a modified Damköhler number that express the joint effect

  15. 2D NMR barcoding and differential analysis of complex mixtures for chemical identification: the Actaea triterpenes.

    Science.gov (United States)

    Qiu, Feng; McAlpine, James B; Lankin, David C; Burton, Ian; Karakach, Tobias; Chen, Shao-Nong; Pauli, Guido F

    2014-04-15

    The interpretation of NMR spectroscopic information for structure elucidation involves decoding of complex resonance patterns that contain valuable molecular information (δ and J), which is not readily accessible otherwise. We introduce a new concept of 2D-NMR barcoding that uses clusters of fingerprint signals and their spatial relationships in the δ-δ coordinate space to facilitate the chemical identification of complex mixtures. Similar to widely used general barcoding technology, the structural information of individual compounds is encoded as a specifics pattern of their C,H correlation signals. Software-based recognition of these patterns enables the structural identification of the compounds and their discrimination in mixtures. Using the triterpenes from various Actaea (syn. Cimicifuga) species as a test case, heteronuclear multiple-bond correlation (HMBC) barcodes were generated on the basis of their structural subtypes from a statistical investigation of their δH and δC data in the literature. These reference barcodes allowed in silico identification of known triterpenes in enriched fractions obtained from an extract of A. racemosa (black cohosh). After dereplication, a differential analysis of heteronuclear single-quantum correlation (HSQC) spectra even allowed for the discovery of a new triterpene. The 2D barcoding concept has potential application in a natural product discovery project, allowing for the rapid dereplication of known compounds and as a tool in the search for structural novelty within compound classes with established barcodes. PMID:24673652

  16. Chemical synthesis and characterization of highly soluble conducting polyaniline in the mixtures of common solvents

    Directory of Open Access Journals (Sweden)

    Zeghioud Hichem

    2015-01-01

    Full Text Available This work presents the synthesis and characterization of soluble and conducting polyaniline PANI-PIA according to chemical polymerization route. This polymerization pathway leads to the formation of poly(itaconic acid doped polyaniline salts, which are highly soluble in a number of mixtures between organic common polar solvents and water, the solubility reaches 4 mg mL-1. The effect of synthesis parameters such as doping level on the conductivity and the study of solubility and other properties of the resulting PANI salts were also undertaken. The maximum of conductivity was found equal to 2.48×10-4 S cm-1 for fully protonated PANI-EB. In addition, various characterizations of the synthesized materials were also done with the help of viscosity measurements, UV-vis spectroscopy, XRD, FTIR and finally TGA for the thermal properties behaviour.

  17. Conversion of Hazardous Motor Vehicle Used Tire and Polystyrene Waste Plastic Mixture into useful Chemical Products

    Directory of Open Access Journals (Sweden)

    Moinuddin Sarker

    2014-02-01

    Full Text Available Motor vehicle used tire and polystyrene waste plastic mixture into fuel recovery using thermal degradation process in laboratory batch process. Motor vehicle used tire and polystyrene waste plastic was use 75 gm by weight. Motor vehicle tire was 25 gm and polystyrene waste plastic was 50 gm. In presence of oxygen experiment was performed under laboratory fume hood. Thermal degradation temperature range was 100 - 420 oC and experiment run time was 5 hours. Product fuel density is 0.84 gm/ml and liquid fuel conversion rate was 54.93 %. Fuel was analysis by GC/MS and compounds are present aliphatic group, aromatic group, alcoholic group, oxygen content and nitrogen content.Fuel can use refinery process as a refinery feed.Keywords: Tire, polystyrene, conversion, chemical product, vehicle, hydrocarbon

  18. A simple procedure for estimating pseudo risk ratios from exposure to non-carcinogenic chemical mixtures.

    Science.gov (United States)

    Scinicariello, Franco; Portier, Christopher

    2016-03-01

    Non-cancer risk assessment traditionally assumes a threshold of effect, below which there is a negligible risk of an adverse effect. The Agency for Toxic Substances and Disease Registry derives health-based guidance values known as Minimal Risk Levels (MRLs) as estimates of the toxicity threshold for non-carcinogens. Although the definition of an MRL, as well as EPA reference dose values (RfD and RfC), is a level that corresponds to "negligible risk," they represent daily exposure doses or concentrations, not risks. We present a new approach to calculate the risk at exposure to specific doses for chemical mixtures, the assumption in this approach is to assign de minimis risk at the MRL. The assigned risk enables the estimation of parameters in an exponential model, providing a complete dose-response curve for each compound from the chosen point of departure to zero. We estimated parameters for 27 chemicals. The value of k, which determines the shape of the dose-response curve, was moderately insensitive to the choice of the risk at the MRL. The approach presented here allows for the calculation of a risk from a single substance or the combined risk from multiple chemical exposures in a community. The methodology is applicable from point of departure data derived from quantal data, such as data from benchmark dose analyses or from data that can be transformed into probabilities, such as lowest-observed-adverse-effect level. The individual risks are used to calculate risk ratios that can facilitate comparison and cost-benefit analyses of environmental contamination control strategies. PMID:25667015

  19. Chemical transformations of complex mixtures relevant to atmospheric processes: Laboratory and ambient studies

    Science.gov (United States)

    Samy, Shahryar (Shar)

    The study of atmospheric chemistry and chemical transformations, which are relevant to conditions in the ambient atmosphere require the investigation of complex mixtures. In the atmosphere, complex mixtures (e.g. diesel emissions) are continually evolving as a result of physical and chemical transformations. This dissertation examines the transformations of modern diesel emissions (DE) in a series of experiments conducted at the European Outdoor Simulation Chamber (EUPHORE) in Valencia, Spain. Experimental design challenges are addressed, and the development of a NOx removal technology (denuder) is described with results from the application of the newly developed NOx denuder in the most recent EUPHORE campaign (2006). In addition, the data from an ambient aerosol study that examines atmospheric transformation products is presented and discussed. Atmospheric transformations of DE and associated secondary organic aerosol (SOA) production, along with chemical characterization of polar organic compounds (POC) in the EUPHORE experiments, provides a valuable insight on the tranformations of modern DE in environmentally relevant atmospheres. The greatest SOA production occurred in DE with toluene addition experiments (>40%), followed by DE with HCHO (for OH radical generation) experiments. A small amount of SOA (3%) was observed for DE in dark with N2O5 (for NO3 radical production) experiments. Distinct POC formation in light versus dark experiments suggests the role of OH initiated reactions in these chamber atmospheres. A trend of increasing concentrations of dicarboxylic acids in light versus dark experiments was observed when evaluated on a compound group basis. The production of diacids (as a compound group) demonstrates a consistent indicator for photochemical transformation in relation to studies in the ambient atmosphere. The four toluene addition experiments in this study were performed at different [tol]o/[NOx]o ratios and displayed an average SOA %yield (in

  20. Subtleties of human exposure and response to chemical mixtures from spills.

    Science.gov (United States)

    Phetxumphou, Katherine; Dietrich, Andrea M; Shanaiah, Narasimhamurthy; Smiley, Elizabeth; Gallagher, Daniel L

    2016-07-01

    Worldwide, chemical spills degrade drinking water quality and threaten human health through ingestion and inhalation. Spills are often mixtures of chemicals; thus, understanding the interaction of chemical and biological properties of the major and minor components is critical to assessing human exposure. The crude (4-methylcyclohexyl)methanol (MCHM) spill provides an opportunity to assess such subtleties. This research determined the relative amounts, volatilization, and biological odor properties of minor components cis- and trans-methyl-4-methylcyclohexanecarboxylate (MMCHC) isomers and major components cis- and trans-4-MCHM, then compared properties and human exposure differences among them. (1)H nuclear magnetic resonance and chromatography revealed that the minor MMCHC isomers were about 1% of the major MCHM isomers. At typical showering temperature of 40 °C, Henry's law constants were 1.50 × 10(-2) and 2.23 × 10(-2) for cis- and trans-MMCHC, respectively, which is 20-50 fold higher than for 4-MCHM isomers. The odor thresholds were 1.83 and 0.02 ppb-v air for cis- and trans-MMCHC, which were both described as predominantly sweet. These data are compared to the higher 120 ppb-v air and 0.06 ppb-v odor thresholds for cis- and trans-4-MCHM, for which the trans-isomer had a dominant licorice descriptor. Application of a shower model demonstrated that while MMCHC isomers are only about 1% of the MCHM isomers, during showering, the MMCHC isomers are 13.8% by volume (16.3% by mass) because of their higher volatility. Trans-4-MCHM contributed about 82% of the odor because of higher volatility and lower odor threshold, trans-MMCHC, which represents 0.3% of the mass, contributed 18% of the odor. This study, with its unique human sensory component to assess exposure, reaffirmed that hazard assessment must not be based solely on relative concentration, but also consider the chemical fate, transport, and biological properties to determine the actual levels of

  1. Toxicology studies of a chemical mixture of 25 groundwater contaminants. II. Immunosuppression in B6C3F1 mice

    Energy Technology Data Exchange (ETDEWEB)

    Germolec, D.R.; Yang, R.S.; Ackermann, M.F.; Rosenthal, G.J.; Boorman, G.A.; Blair, P.; Luster, M.I. (National Institutes of Environmental Health Sciences, Research Triangle Park, NC (USA))

    1989-10-01

    Concern over the potential adverse health effects of chemically contaminated groundwater has existed for many years. In general, these studies have focused on retrospective epidemiological studies for cancer risk. In the present studies, immune function was monitored in female B6C3F1 mice exposed to a chemical mixture in drinking water for either 14 or 90 days. The mixture consisted of 25 common groundwater contaminants frequently found near toxic waste dumps, as determined by EPA surveys. None of the animals developed overt signs of toxicity such as body or liver weight changes. Mice exposed to the highest dose of this mixture for 14 or 90 days showed immune function changes which could be related to rapidly proliferating cells, including suppression of hematopoietic stem cells and of antigen-induced antibody-forming cells. Some of these responses, e.g., granulocyte-macrophage colony formation, were also suppressed at lower concentrations of the chemical mixture. There were no effects on T cell function or T and B cell numbers in any of the treatment groups. Altered resistance to challenge with an infectious agent also occurred in mice given the highest concentration, which correlated with the immune function changes. Paired-water studies indicated that the immune effects were related to chemical exposure and not to decreased water intake. These results suggest that long-term exposure to contaminated groundwater may represent a risk to the immune system in humans.

  2. Probabilistic Health Risk Assessment of Chemical Mixtures: Importance of Travel Times and Connectivity

    Science.gov (United States)

    Henri, Christopher V.; Fernàndez-Garcia, Daniel; de Barros, Felipe P. J.

    2014-05-01

    Subsurface contamination cases giving rise to groundwater pollutions are extensively found in all industrialized countries. Under this pressure, risk assessment methods play an important role in population protection by (1) quantifying the potential impact on human health of an aquifer contamination and (2) helping and driving decisions of groundwater-resource managers. Many reactive components such as chlorinated solvents or nitrates potentially experience attenuation processes under common geochemical conditions. This represents an attractive and extensively used remediation solution but leads often to the production of by-products before to reach a harmless chemical form. This renders mixtures of contaminants a common issue for groundwater resources managers. In this case, the threat posed by these contaminants to human health at a given sensitive location greatly depends on the competition between reactive and advective-dispersive characteristic times. However, hydraulic properties of the aquifer are known to be spatially variable, which can lead to the formation of preferential flow channels and fast contamination pathways. Therefore, the uncertainty on the spatial distribution of the aquifer properties controlling the plume travel time may then play a particular role in the human health risk assessment of chemical mixtures. We investigate here the risk related to a multispecies system in response to different degrees of heterogeneity of the hydraulic conductivity (K or Y =ln(K)). This work focuses on a Perchloroethylene (PCE) contamination problem followed by the sequential first-order production/biodegradation of its daughter species Trichloroethylene (TCE), Dichloroethylene (DCE) and Vinyl Chlorine (VC). For this specific case, VC is known to be a highly toxic contaminant. By performing numerical experiments, we evaluate transport through three-dimensional mildly (σY 2=1.0) and highly (σY 2=4.0) heterogeneous aquifers. Uncertainty on the hydraulic

  3. Atmospheric pressure chemical ionization Fourier transform ion cyclotron resonance mass spectrometry for complex thiophenic mixture analysis

    KAUST Repository

    Hourani, Nadim

    2013-10-01

    Rationale Polycyclic aromatic sulfur heterocycles (PASHs) are detrimental species for refining processes in petroleum industry. Current mass spectrometric Methods that determine their composition are often preceded by derivatization and dopant addition approaches. Different ionization Methods have different impact on the molecular assignment of complex PASHs. The analysis of such species under atmospheric pressure chemical ionization (APCI) is still considered limited due to uncontrolled ion generation with low- and high-mass PASHs. Methods The ionization behavior of a model mixture of five selected PASH standards was investigated using an APCI source with nitrogen as the reagent gas. A complex thiophenic fraction was separated from a vacuum gas oil (VGO) and injected using the same method. The samples were analyzed using Fourier transform ion cyclotron resonance mass spectrometry (FTICR MS). RESULTS PASH model analytes were successfully ionized and mainly [M + H]+ ions were produced. The same ionization pattern was observed for the real thiophenic sample. It was found that S1 class species were the major sulfur-containing species found in the VGO sample. These species indicated the presence of alkylated benzothiophenic (BT), dibenzothiophenic (DBT) and benzonaphthothiophenic (BNT) series that were detected by APCI-FTICR MS. CONCLUSIONS This study provides an established APCI-FTICR MS method for the analysis of complex PASHs. PASHs were detected without using any derivatization and without fragmentation. The method can be used for the analysis of S-containing crude oil samples. © 2013 John Wiley & Sons, Ltd.

  4. The Effect of Perfluorooctane Sulfonate, Exposure Time, and Chemical Mixtures on Methanogenic Community Structure and Function

    OpenAIRE

    McNamara, Patrick J.; LaPara, Timothy M.; Novak, Paige J

    2015-01-01

    A plethora of organic micropollutant mixtures are found in untreated municipal wastewater. Anaerobic digesters receive large loadings of hydrophobic micropollutants that sorb to wastewater biosolids. Despite micropollutants being pervasive as mixtures, little research is available to explain the impact that mixtures of compounds, as well as exposure time, have on microbial communities in anaerobic digesters. Perfluorooctane sulfonate (PFOS) was added to anaerobic enrichment cultures in both s...

  5. Physical-chemical characteristics of an eco-friendly binder using ternary mixture of industrial wastes

    Directory of Open Access Journals (Sweden)

    Nguyen, Hoang-Anh

    2015-09-01

    Full Text Available This study explores the physical-chemical characteristics of paste and mortar with an eco-friendly binder named as SFC cement, produced by a ternary mixture of industrial waste materials of ground granulated blast furnace slag (S, Class F fly ash (FFA, and circulating fluidized bed combustion fly ash (CFA. To trigger the hydration, the CFA, which acted as an alkaline-sulfate activator, was added to the blended mixture of slag and FFA. The water to binder ratio (W/B, curing regime, and FFA addition significantly affected the engineering performances and shrinkage/expansion of the SFC pastes and mortars. The SFC mortars had higher workability than that of ordinary Portland cement (OPC. With similar workability, the SFC mortars had compressive strengths and expansions comparable to OPC mortars. The main hydration products of the hardened SFC cement were ettringite (AFt and C-S-H/C-A-S-H. The transformation of the AFt to the monosulfates was observed as the hydration time increased.Este trabajo estudia las características fisicoquímicas de pastas y morteros con un ligante eco-amigable llamado cemento SFC, producido por una mezcla ternaria de materiales a partir de residuos industriales tales como escorias granuladas de alto horno (S, ceniza volante clase F (FFA, y cenizas volantes de combustión en lecho fluidizado circulante (CFA. Para desencadenar la hidratación, el CFA que actuó como un activador alcalino-sulfato se añadió a la mezcla combinada de escoria y FFA. La relación de agua/ligante (W/B, el tipo de curado, y la adición de FFA afectaron significativamente a las prestaciones mecánicas así como a la retracción/expansión de pastas y morteros de SFC. Los morteros SFC presentaron una trabajabilidad mayor que los correspondientes de cemento de Portland (OPC. Con una trabajabilidad similar, los morteros SFC presentaron resistencias mecánicas y expansión comparables a los morteros de OPC. Los principales productos de hidratación del

  6. The chemical kinetics of the reactions of lithium with steam-air mixtures

    International Nuclear Information System (INIS)

    This work involved the experimental and analytical determination of the consequences of lithium fires in the presence of steam. Experiments were performed to characterize the chemical reactions of lithium with steam-nitrogen and steam-air mixtures. Models were introduced in the LITFIRE code to describe lithium fires in the presence of steam inside the containment building and plasma chamber of a hypothetical fusion reactor. The code was also equipped with the capability to determine the effects of decay heat and lithium fire on the temperature response of the reactor first wall in the event of a coolant disturbance. Forty-two kinetics experiments were performed in which a stream of steam-nitrogen or steam-air was passed over and reacted with approximately three grams of lithium heated to a predetermined temperature. The lithium reaction rates with the constituent gases were measured and characterized for a wide range of lithium temperatures and gas compositions. Experiments were performed with steam molar concentrations of 5, 15 and 30% and lithium temperatures ranging from 400 to 1100 degree C, inclusive. The LITFIRE code was modified to enable it to model the interactions of lithium with steam-air atmospheres. Results of the reaction kinetics experiments were used in the reaction model, and the heat transfer model was expanded to allow it to handle condensible atmospheres. Three groups of accidents were investigated: a spill on the containment building floor, a spill inside the reactor plasma chamber, and a spill inside the plasma chamber with steam injection to the containment building simulating a steam line break. The results were compared to dry air cases under the same conditions. 23 refs., 66 figs., 18 tabs

  7. Perinatal exposure to mixtures of endocrine disrupting chemicals reduces female rat follicle reserves and accelerates reproductive aging.

    Science.gov (United States)

    Johansson, Hanna Katarina Lilith; Jacobsen, Pernille Rosenskjold; Hass, Ulla; Svingen, Terje; Vinggaard, Anne Marie; Isling, Louise Krag; Axelstad, Marta; Christiansen, Sofie; Boberg, Julie

    2016-06-01

    Exposure to endocrine disrupting chemicals (EDCs) during development can have negative consequences later in life. In this study we investigated the effect of perinatal exposure to mixtures of human relevant EDCs on the female reproductive system. Rat dams were exposed to a mixture of phthalates, pesticides, UV-filters, bisphenol A, butylparaben, as well as paracetamol. The compounds were tested together (Totalmix) or in subgroups with anti-androgenic (AAmix) or estrogenic (Emix) potentials. Paracetamol was tested separately. In pre-pubertal rats, a significant reduction in primordial follicle numbers was seen in AAmix and PM groups, and reduced plasma levels of prolactin was seen in AAmix. In one-year-old animals, the incidence of irregular estrous cycles was higher after Totalmix-exposure and reduced ovary weights were seen in Totalmix, AAmix, and PM groups. These findings resemble premature ovarian insufficiency in humans, and raises concern regarding potential effects of mixtures of EDCs on female reproductive function. PMID:27049580

  8. Transport of heavy metals and chemical compatibility of hydraulic conductivity of a compacted sand-bentonite mixture

    Directory of Open Access Journals (Sweden)

    Nanthanit Charoenthaisong

    2008-03-01

    Full Text Available Clayey soils are usually used as barrier material in landfill liners because of its low hydraulic conductivity and high sorption capacity. Bentonite, which consists mainly of montmorillonite, has a high cation exchange capacity resulting in a high retention capacity of heavy metals. Sand is a permeable material but its hydraulic conductivity decreases significantly when mixed with bentonite. However, using a sand-bentonite mixture as landfill liners is questionable, because the hydraulic conductivity of the sand-bentonite mixture may increase when permeated with heavy metal solutions, which are normally found in landfill leachates. In this paper, transport of heavy metals through a compacted sand-bentonite mixture and its chemical compatibility were studied through the batch adsorption test, the column test, and the hydraulic conductivity test.Experimental results indicate that the sorption capacity of the bentonite, ranked in descending order, was Cr3+, Pb2+, Cd2+, Zn2+, and Ni2+, respectively. The diffusion coefficients of the sand-bentonite mixture were in the order of 10-5 cm2/s and the retardation factors were 130, 115, 111, and 90 for Pb2+, Ni2+, Zn2+, and Cd2+, respectively. The hydraulic conductivity of thesand-bentonite mixture was only compatible with a chromium solution having a concentration not greater than 0.001 M.

  9. Application of TCF bleaching in mixtures of chemical and mechanics fibers recycled: alternative for the paper industry

    International Nuclear Information System (INIS)

    In this paper we study the technical feasibility of using mixtures composed by mechanical and chemical fibers recycled in the production of tissue paper, using TCF bleaching sequences that improve the optical properties of this raw material. At present, chemical fibers recycled are used, but their limited availability and high cost,stimulate the search for raw materials which replace them partially. Bleaching stages were carried out at atmospheric pressure, with the oxidative process made with hydrogen peroxide at 80 celsius degrade in 1.5 hours and the reductive stage with FAS, VBrite, Thiourea Dioxide in situ or Chromaclear at 60 celsius degrade for 1 hour. The obtained results allow to deduce that the addition of mechanical recycled fiber significantly affects the optical properties of mixtures. However, some of the bleaching sequences applied manage to compensate, at least partly, the effect of adding this raw material of lower quality and cost.

  10. Transport of a liquid water and methanol mixture through carbon nanotubes under a chemical potential gradient

    Science.gov (United States)

    Zheng, Jie; Lennon, Erin M.; Tsao, Heng-Kwong; Sheng, Yu-Jane; Jiang, Shaoyi

    2005-06-01

    In this work, we report a dual-control-volume grand canonical molecular dynamics simulation study of the transport of a water and methanol mixture under a fixed concentration gradient through nanotubes of various diameters and surface chemistries. Methanol and water are selected as fluid molecules since water represents a strongly polar molecule while methanol is intermediate between nonpolar and strongly polar molecules. Carboxyl acid (-COOH) groups are anchored onto the inner wall of a carbon nanotube to alter the hydrophobic surface into a hydrophilic one. Results show that the transport of the mixture through hydrophilic tubes is faster than through hydrophobic nanotubes although the diffusion of the mixture is slower inside hydrophilic than hydrophobic pores due to a hydrogen network. Thus, the transport of the liquid mixture through the nanotubes is controlled by the pore entrance effect for which hydrogen bonding plays an important role.

  11. Chemical speciation and association of plutonium with bacteria, kaolinite clay, and their mixture.

    Science.gov (United States)

    Ohnuki, Toshihiko; Yoshida, Takahiro; Ozaki, Takuo; Kozai, Naofumi; Sakamoto, Fuminori; Nankawa, Takuya; Suzuki, Yoshinori; Francis, Arokiasamy J

    2007-05-01

    We investigated the interactions of Pu(VI) with Bacillus subtilis, kaolinite clay, and a mixture of the two to determine and delineate the role of the microbes in regulating the environmental mobility of Pu. The bacteria, the kaolinite, and their mixture were exposed to a 4 x 10(-4) M Pu(VI) solution at pH 5.0. The amount of Pu sorbed by B. subtilis increased with time, but had not reached equilibrium in 48 h, whereas equilibrium was attained in kaolinite within 8 h. After 48 h, the oxidation state of Pu in the solutions exposed to B. subtilis and the mixture had changed to Pu-(V), whereas the oxidation state of Pu associated with B. subtilis and the mixture was Pu(IV). Exudates released from B. subtilis reduced Pu(VI) to Pu(V). In contrast, there was no change in the oxidation state of Pu in the solution or on kaolinite after exposure to Pu(VI). Scanning electron microscopy-energy dispersive spectrometry analysis indicated that most of the Pu in the mixture was associated with B. subtilis. These results suggest that Pu-(IV) is preferably sorbed to bacterial cells in the mixture and that Pu(VI) is reduced to Pu(V) and Pu(IV). PMID:17539516

  12. Optimization of ammonia-peroxide water mixture (APM) for high volume manufacturing through surface chemical investigations

    Science.gov (United States)

    Siddiqui, Shariq

    Ammonia-peroxide mixture (APM) is a widely used wet chemical system for particle removal from silicon surfaces. The conventional APM solution in a volume ratio of 1:1:5 (NH4OH:H2O2:H 2O) is employed at elevated temperatures of 70--80 °C. At these temperatures, APM solution etch es silicon at a rate of ˜3 A/min, which is unacceptable for current technology node. Additionally, APM solutions are unstable due to the decomposition of hydrogen peroxide and evaporative loss of ammonium hydroxide resulting in the change in APM solution composition. This has generated interest in the use of dilute APM solutions. However, dilution ratios are chosen without any established fundamental relationship between particle-wafer interactions and APM solutions. Atomic force microscopy has been used to measure interaction forces between H-terminated Si surface and Si tip in APM solutions of different compositions. The approach force curves results show attractive forces in DI-water, NH 4OH:H2O (1:100) and H2O2:H2O (1:100) solutions at separation distances of less than 10 nm for all immersion times (2, 10 and 60 min) investigated. In the case of dilute APM solutions, the forces are purely repulsive within 2 min of immersion time. During retraction, the adhesion force between Si surface and Si tip was in the range of 0.8 nN to 10.0 nN. In dilute APM solutions, no adhesion force is measured between Si surfaces and repulsive forces dominated at all distances. These results show that even in very dilute APM solutions, repulsive forces exist between Si surface and particle re-deposition can be prevented. The stability of APM solutions has been investigated as a function of temperature (24--65 °C), dilution ratio (1:1:5--1:2:100), solution pH (8.0--9.7) and Fe2+ concentration (0--10 ppb) using an optical concentration monitor. The results show that the rate of H2O2 decomposition increased with an increase in temperature, solution pH and Fe2+ concentration. The kinetic analysis showed that

  13. Determinants of Exposure to Fragranced Product Chemical Mixtures in a Sample of Twins

    Directory of Open Access Journals (Sweden)

    Matthew O. Gribble

    2015-01-01

    Full Text Available Fragranced product chemical mixtures may be relevant for environmental health, but little is known about exposure. We analyzed results from an olfactory challenge with the synthetic musk fragrance 1,3,4,6,7,8-hexahydro-4,6,6,7,8,8-hexamethyl-cyclopento-γ-2-benzopyran (HHCB, and a questionnaire about attitudes toward chemical safety and use of fragranced products, in a sample of 140 white and 17 black twin pairs attending a festival in Ohio. Data for each product were analyzed using robust ordered logistic regressions with random intercepts for “twin pair” and “sharing address with twin”, and fixed effects for sex, age, education, and “ever being bothered by fragrances”. Due to the small number of black participants, models were restricted to white participants except when examining racial differences. Overall patterns of association were summarized across product-types through random-effects meta-analysis. Principal components analysis was used to summarize clustering of product use. The dominant axis of variability in fragranced product use was “more vs. less”, followed by a distinction between household cleaning products and personal care products. Overall, males used fragranced products less frequently than females (adjusted proportionate odds ratio 0.55, 95% confidence interval 0.33, 0.93. This disparity was driven by personal care products (0.42, 95% CI: 0.19, 0.96, rather than household cleaning products (0.79, 95% CI: 0.49, 1.25 and was particularly evident for body lotion (0.12, 95% CI: 0.05, 0.27. Overall usage differed by age (0.64, 95% CI: 0.43, 0.95 but only hand soap and shampoo products differed significantly. “Ever being bothered by fragrance” had no overall association (0.92, 95% CI: 0.65, 1.30 but was associated with laundry detergent use (0.46, 95% CI: 0.23, 0.93. Similarly, black vs. white differences on average were not significant (1.34, 95% CI: 0.55, 3.28 but there were apparent differences in use of

  14. Proceedings of the 1. Arabic conference on chemical applications (Chemia 2). Vol. 2

    International Nuclear Information System (INIS)

    The conference of chemical application was held on 1-5 Nov 1997 in Cairo, This vol.2 contains of chemical application on nuclear materials. Studies on these vol.This second volume covers papers presented on the subjects

  15. Evaluation of an extraction method for a mixture of endocrine disrupters in sediment using chemical and in vitro biological analyses.

    Science.gov (United States)

    Creusot, Nicolas; Dévier, Marie-Hélène; Budzinski, Hélène; Aït-Aïssa, Selim

    2016-06-01

    Aquatic sediments are contaminated by a wide diversity of organic pollutants such as endocrine-disrupting chemicals (EDCs) which encompass a broad range of chemical classes having natural and anthropogenic origins. The use of in vitro bioassays is now widely accepted as an alternative method for their detection in complex samples. However, based on the diversity of EDC chemical properties, their common extraction is difficult and comprehensive validation of extraction methods for a bioanalysis purpose is still weakly documented. In this study, we compared the performance of several organic solvents, i.e., acetone, methanol, dichloromethane, heptane, dichloromethane/acetone (50:50, v/v), dichloromethane/methanol (50:50, v/v), heptane/acetone (50:50, v/v), and heptane/methanol (50:50, v/v), to extract a diversity of active chemicals from a spiked sediment matrix using pressurized liquid extraction. For this purpose, we defined a mixture of 12 EDCs with a wide range of polarity (2 PCB-126, 2,3,7,8 TCDD, benzo[k]fluoranthene, and dibenzo[a,h]anthracene). Working concentrations of each individual compound in the mixture were determined as equipotent concentrations on the basis of the concentration-addition (CA) model applied to in vitro estrogenic, dioxin-like, and pregnane X receptor (PXR)-like activities. Extraction efficiencies based on both chemical and biological analyses were assessed in triplicate in artificial blank sediment spiked with this mixture and in natural sediment contaminated by native EDCs. In both spiked and natural sediment, MeOH/DCM yields the best recovery while heptane was the least efficient solvent. Our study provided the validation of a sediment extraction methodology for EDC bioanalysis purposes, which can be used for comprehensive environmental contamination characterization. PMID:26832862

  16. Susceptibility of Microsporum canis arthrospores to a mixture of chemically defined essential oils: a perspective for environmental decontamination.

    Science.gov (United States)

    Nardoni, Simona; Tortorano, Annamaria; Mugnaini, Linda; Profili, Greta; Pistelli, Luisa; Giovanelli, Silvia; Pisseri, Francesca; Papini, Roberto; Mancianti, Francesca

    2015-01-01

    The zoophilic dermatophyte Microsporum canis has cats as natural reservoir, but it is able to infect a wide range of hosts, including humans, where different clinical features of the so-called ringworm dermatophytosis have been described. Human infections are increasingly been reported in Mediterranean countries. A reliable control program against M. canis infection in cats should include an antifungal treatment of both the infected animals and their living environment. In this article, a herbal mixture composed of chemically defined essential oils (EOs) of Litsea cubeba (1%), Illicium verum, Foeniculum vulgare, and Pelargonium graveolens (0.5% each) was formulated and its antifungal activity assessed against M. canis arthrospores which represent the infective environmental stage of M. canis. Single compounds present in higher amounts in the mixture were also separately tested in vitro. Litsea cubeba and P. graveolens EOs were most effective (minimum inhibitory concentration (MIC) 0.5%), followed by EOs of I. verum (MIC 2%) and F. vulgare (MIC 2.5%). Minimum fungicidal concentrations (MFC) values were 0.75% (L. cubeba), 1.5% (P. graveolens), 2.5% (I. verum) and 3% (F. vulgare). MIC and MFC values of the mixture were 0.25% and 0.5%, respectively. The daily spray of the mixture (200 μL) directly onto infected hairs inhibited fungal growth from the fourth day onwards. The compounds present in higher amounts exhibited variable antimycotic activity, with MIC values ranging from >10% (limonene) to 0.1% (geranial and neral). Thus, the mixture showed a good antifungal activity against arthrospores present in infected hairs. These results are promising for a further application of the mixture as an alternative tool or as an adjuvant in the environmental control of feline microsporosis. PMID:25854840

  17. Assessing the carcinogenic potential of low-dose exposures to chemical mixtures in the environment: the challenge ahead

    Science.gov (United States)

    Goodson, William H.; Lowe, Leroy; Carpenter, David O.; Gilbertson, Michael; Manaf Ali, Abdul; Lopez de Cerain Salsamendi, Adela; Lasfar, Ahmed; Carnero, Amancio; Azqueta, Amaya; Amedei, Amedeo; Charles, Amelia K.; Collins, Andrew R.; Ward, Andrew; Salzberg, Anna C.; Colacci, Anna Maria; Olsen, Ann-Karin; Berg, Arthur; Barclay, Barry J.; Zhou, Binhua P.; Blanco-Aparicio, Carmen; Baglole, Carolyn J.; Dong, Chenfang; Mondello, Chiara; Hsu, Chia-Wen; Naus, Christian C.; Yedjou, Clement; Curran, Colleen S.; Laird, Dale W.; Koch, Daniel C.; Carlin, Danielle J.; Felsher, Dean W.; Roy, Debasish; Brown, Dustin G.; Ratovitski, Edward; Ryan, Elizabeth P.; Corsini, Emanuela; Rojas, Emilio; Moon, Eun-Yi; Laconi, Ezio; Marongiu, Fabio; Al-Mulla, Fahd; Chiaradonna, Ferdinando; Darroudi, Firouz; Martin, Francis L.; Van Schooten, Frederik J.; Goldberg, Gary S.; Wagemaker, Gerard; Nangami, Gladys N.; Calaf, Gloria M.; Williams, Graeme P.; Wolf, Gregory T.; Koppen, Gudrun; Brunborg, Gunnar; Lyerly, H. Kim; Krishnan, Harini; Ab Hamid, Hasiah; Yasaei, Hemad; Sone, Hideko; Kondoh, Hiroshi; Salem, Hosni K.; Hsu, Hsue-Yin; Park, Hyun Ho; Koturbash, Igor; Miousse, Isabelle R.; Scovassi, A.Ivana; Klaunig, James E.; Vondráček, Jan; Raju, Jayadev; Roman, Jesse; Wise, John Pierce; Whitfield, Jonathan R.; Woodrick, Jordan; Christopher, Joseph A.; Ochieng, Josiah; Martinez-Leal, Juan Fernando; Weisz, Judith; Kravchenko, Julia; Sun, Jun; Prudhomme, Kalan R.; Narayanan, Kannan Badri; Cohen-Solal, Karine A.; Moorwood, Kim; Gonzalez, Laetitia; Soucek, Laura; Jian, Le; D’Abronzo, Leandro S.; Lin, Liang-Tzung; Li, Lin; Gulliver, Linda; McCawley, Lisa J.; Memeo, Lorenzo; Vermeulen, Louis; Leyns, Luc; Zhang, Luoping; Valverde, Mahara; Khatami, Mahin; Romano, Maria Fiammetta; Chapellier, Marion; Williams, Marc A.; Wade, Mark; Manjili, Masoud H.; Lleonart, Matilde E.; Xia, Menghang; Gonzalez Guzman, Michael J.; Karamouzis, Michalis V.; Kirsch-Volders, Micheline; Vaccari, Monica; Kuemmerle, Nancy B.; Singh, Neetu; Cruickshanks, Nichola; Kleinstreuer, Nicole; van Larebeke, Nik; Ahmed, Nuzhat; Ogunkua, Olugbemiga; Krishnakumar, P.K.; Vadgama, Pankaj; Marignani, Paola A.; Ghosh, Paramita M.; Ostrosky-Wegman, Patricia; Thompson, Patricia A.; Dent, Paul; Heneberg, Petr; Darbre, Philippa; Leung, Po Sing; Nangia-Makker, Pratima; Cheng, Qiang (Shawn); Robey, R.Brooks; Al-Temaimi, Rabeah; Roy, Rabindra; Andrade-Vieira, Rafaela; Sinha, Ranjeet K.; Mehta, Rekha; Vento, Renza; Di Fiore, Riccardo; Ponce-Cusi, Richard; Dornetshuber-Fleiss, Rita; Nahta, Rita; Castellino, Robert C.; Palorini, Roberta; Hamid, Roslida A.; Langie, Sabine A.S.; Eltom, Sakina E.; Brooks, Samira A.; Ryeom, Sandra; Wise, Sandra S.; Bay, Sarah N.; Harris, Shelley A.; Papagerakis, Silvana; Romano, Simona; Pavanello, Sofia; Eriksson, Staffan; Forte, Stefano; Casey, Stephanie C.; Luanpitpong, Sudjit; Lee, Tae-Jin; Otsuki, Takemi; Chen, Tao; Massfelder, Thierry; Sanderson, Thomas; Guarnieri, Tiziana; Hultman, Tove; Dormoy, Valérian; Odero-Marah, Valerie; Sabbisetti, Venkata; Maguer-Satta, Veronique; Rathmell, W.Kimryn; Engström, Wilhelm; Decker, William K.; Bisson, William H.; Rojanasakul, Yon; Luqmani, Yunus; Chen, Zhenbang; Hu, Zhiwei

    2015-01-01

    Lifestyle factors are responsible for a considerable portion of cancer incidence worldwide, but credible estimates from the World Health Organization and the International Agency for Research on Cancer (IARC) suggest that the fraction of cancers attributable to toxic environmental exposures is between 7% and 19%. To explore the hypothesis that low-dose exposures to mixtures of chemicals in the environment may be combining to contribute to environmental carcinogenesis, we reviewed 11 hallmark phenotypes of cancer, multiple priority target sites for disruption in each area and prototypical chemical disruptors for all targets, this included dose-response characterizations, evidence of low-dose effects and cross-hallmark effects for all targets and chemicals. In total, 85 examples of chemicals were reviewed for actions on key pathways/mechanisms related to carcinogenesis. Only 15% (13/85) were found to have evidence of a dose-response threshold, whereas 59% (50/85) exerted low-dose effects. No dose-response information was found for the remaining 26% (22/85). Our analysis suggests that the cumulative effects of individual (non-carcinogenic) chemicals acting on different pathways, and a variety of related systems, organs, tissues and cells could plausibly conspire to produce carcinogenic synergies. Additional basic research on carcinogenesis and research focused on low-dose effects of chemical mixtures needs to be rigorously pursued before the merits of this hypothesis can be further advanced. However, the structure of the World Health Organization International Programme on Chemical Safety ‘Mode of Action’ framework should be revisited as it has inherent weaknesses that are not fully aligned with our current understanding of cancer biology. PMID:26106142

  18. Influence of Wetting and Mass Transfer Properties of Organic Chemical Mixtures in Vadose Zone Materials on Groundwater Contamination by Nonaqueous Phase Liquids

    Energy Technology Data Exchange (ETDEWEB)

    Charles J Werth; Albert J Valocchi, Hongkyu Yoon

    2011-05-21

    Previous studies have found that organic acids, organic bases, and detergent-like chemicals change surface wettability. The wastewater and NAPL mixtures discharged at the Hanford site contain such chemicals, and their proportions likely change over time due to reaction-facilitated aging. The specific objectives of this work were to (1) determine the effect of organic chemical mixtures on surface wettability, (2) determine the effect of organic chemical mixtures on CCl4 volatilization rates from NAPL, and (3) accurately determine the migration, entrapment, and volatilization of organic chemical mixtures. Five tasks were proposed to achieve the project objectives. These are to (1) prepare representative batches of fresh and aged NAPL-wastewater mixtures, (2) to measure interfacial tension, contact angle, and capillary pressure-saturation profiles for the same mixtures, (3) to measure interphase mass transfer rates for the same mixtures using micromodels, (4) to measure multiphase flow and interphase mass transfer in large flow cell experiments, all using the same mixtures, and (5) to modify the multiphase flow simulator STOMP in order to account for updated P-S and interphase mass transfer relationships, and to simulate the impact of CCl4 in the vadose zone on groundwater contamination. Results and findings from these tasks and summarized in the attached final report.

  19. MODELING A MIXTURE: PBPK/PD APPROACHES FOR PREDICTING CHEMICAL INTERACTIONS.

    Science.gov (United States)

    Since environmental chemical exposures generally involve multiple chemicals, there are both regulatory and scientific drivers to develop methods to predict outcomes of these exposures. Even using efficient statistical and experimental designs, it is not possible to test in vivo a...

  20. Low dose mixture effects of endocrine disrupters and their implications for regulatory thresholds in chemical risk assessment.

    Science.gov (United States)

    Kortenkamp, Andreas

    2014-12-01

    Today's chemical exposures are characterised by a widely spread blanket of contamination composed of myriads of chemicals, many of them endocrine disrupters, all at rather low levels. With their focus on considering single chemicals one by one, the approaches used by regulatory bodies worldwide for safety assessments of chemicals cannot keep up with these pollution patterns. A substantial challenge lies in the assessment of combination effects from large numbers of endocrine disrupters and other chemicals, all at low doses. We retrace the development of experimental and conceptual approaches required for assessing low dose mixtures, with an emphasis on work with endocrine disrupting chemicals. We find that nearly 20 years of research has produced good evidence for combination effects at levels around experimental thresholds. One obstacle in deciding on the relevance of this evidence is incomplete information about the range of endocrine-disrupting chemicals that make up combined exposures. These knowledge gaps need to be closed urgently, as is currently discussed under the heading of exposome research. PMID:25244397

  1. Combining polar organic chemical integrative samplers (POCIS) with toxicity testing to evaluate pesticide mixture effects on natural phototrophic biofilms

    International Nuclear Information System (INIS)

    Polar organic chemical integrative samplers (POCIS) are valuable tools in passive sampling methods for monitoring polar organic pesticides in freshwaters. Pesticides extracted from the environment using such methods can be used to toxicity tests. This study evaluated the acute effects of POCIS extracts on natural phototrophic biofilm communities. Our results demonstrate an effect of POCIS pesticide mixtures on chlorophyll a fluorescence, photosynthetic efficiency and community structure. Nevertheless, the range of biofilm responses differs according to origin of the biofilms tested, revealing spatial variations in the sensitivity of natural communities in the studied stream. Combining passive sampler extracts with community-level toxicity tests offers promising perspectives for ecological risk assessment. - Research highlights: → Polar organic chemical integrative samplers (POCIS) were used for monitoring polar organic pesticides in a contaminated river. → The acute effects of POCIS extracts were tested on natural phototrophic biofilm communities. → POCIS pesticide mixtures affected chlorophyll a fluorescence, photosynthetic efficiency and community structure. → Biofilm responses differed according to origin of the biofilms tested, revealing variations in the sensitivity of natural communities. → Combining passive sampler extracts with community-level toxicity tests offers promising perspectives for ecological risk assessment. - Pesticide mixtures extracted from POCIS can affect chl a fluorescence, photosynthetic efficiency and community structure of natural biofilms.

  2. A preliminary investigation into the physical and chemical properties of biomass ashes used as aggregate fillers for bituminous mixtures.

    Science.gov (United States)

    Melotti, Roberto; Santagata, Ezio; Bassani, Marco; Salvo, Milena; Rizzo, Stefano

    2013-09-01

    Fly and bottom ashes are the main by-products arising from the combustion of solid biomass. Since the production of energy from this source is increasing, the processing and disposal of the resulting ashes has become an environmental and economic issue. Such ashes are of interest as a construction material because they are composed of very fine particles similar to fillers normally employed in bituminous and cementitious mixtures. This research investigates the potential use of ash from biomass as filler in bituminous mixtures. The morphological, physical and chemical characteristics of 21 different ashes and two traditional fillers (calcium carbonate and "recovered" plant filler) were evaluated and discussed. Leaching tests, performed in order to quantify the release of pollutants, revealed that five ashes do not comply with the Italian environmental re-use limits. Experimental results show a wide range of values for almost all the investigated properties and a low correlation with biomass type in terms of origin and chemical composition. Furthermore, sieving and milling processes were found to improve the properties of the raw material in terms of grading and sample porosity. The effectiveness of these treatments and the low content of organic matter and harmful fines suggest that most of the biomass ashes investigated may be regarded as potential replacements for natural filler in bituminous mixtures. PMID:23790672

  3. Demonstration of a rapidly-swept external cavity quantum cascade laser for rapid and sensitive quantification of chemical mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Brumfield, Brian E.; Taubman, Matthew S.; Phillips, Mark C.

    2016-02-13

    A rapidly-swept external cavity quantum cascade laser (ECQCL) system for fast open-path quantification of multiple chemicals and mixtures is presented. The ECQCL system is swept over its entire tuning range (>100 cm-1) at frequencies up to 200 Hz. At 200 Hz the wavelength tuning rate and spectral resolution are 2x104 cm-1/sec and < 0.2 cm-1, respectively. The capability of the current system to quantify changes in chemical concentrations on millesecond timescales is demonstrated at atmospheric pressure using an open-path multi-pass cell. The detection limits for chemicals ranged from ppb to ppm levels depending on the absorption cross-section.

  4. Identifying changes in chemical, interfacial and foam properties of ß-lactoglobulin–sodium dodecyl sulphate mixtures

    NARCIS (Netherlands)

    Lech, F.J.; Steltenpool, P.; Meinders, M.B.J.; Sforza, S.; Gruppen, H.; Wierenga, P.A.

    2014-01-01

    Techno-functional properties of proteins, such as foam stability, can be affected by the presence of low-molecular-weight surfactants. In order to understand and control the foam properties of such protein–surfactant mixtures, a thorough characterization of foam and interfacial properties needs to b

  5. Conversion of the chemical concentration of odorous mixtures into odour concentration and odour intensity: a comparison of methods

    CERN Document Server

    Wu, C; Zhao, P; Piringer, M; Schauberger, G

    2015-01-01

    Continuous odour measurements both of emissions as well as ambient concentrations are seldom realised, mainly because of their high costs. They are therefore often substituted by concentration measurements of odorous substances. Then a conversion of the chemical concentrations C (mg m-3) into odour concentrations COD (ouE m-3) and odour intensities OI is necessary. Four methods to convert the concentrations of single substances to the odour concentrations and odour intensities of an odorous mixture are investigated: (1) direct use of measured concentrations, (2) the sum of the odour activity value SOAV, (3) the sum of the odour intensities SOI, and (4) the equivalent odour concentration EOC, as a new method. The methods are evaluated with olfactometric measurements of seven substances as well as their mixtures. The results indicate that the SOI and EOC conversion methods deliver reliable values. These methods use not only the odour threshold concentration but also the slope of the Weber-Fechner law to include...

  6. Proceedings of the DOE chemical energy storage and hydrogen energy systems contracts review

    Energy Technology Data Exchange (ETDEWEB)

    1980-02-01

    Sessions were held on electrolysis-based hydrogen storage systems, hydrogen production, hydrogen storage systems, hydrogen storage materials, end-use applications and system studies, chemical heat pump/chemical energy storage systems, systems studies and assessment, thermochemical hydrogen production cycles, advanced production concepts, and containment materials. (LHK)

  7. Proceedings of the 1. Arabic conference on chemical applications (Chemia 2). Vol. 1

    International Nuclear Information System (INIS)

    The 1. Arabic conference on chemical applications was held on 1-5 Nov 1997 in Cairo. The specialists discussed the chemical applications for environmental service. This first volume covers papers presented on the subjects environmental protection of pollution, nuclear materials and environment, nuclear materials and industry

  8. Mixtures of chemical pollutants at European legislation safety concentrations: how safe are they?

    DEFF Research Database (Denmark)

    Carvalho, Raquel N.; Arukwe, Augustine; Ait-Aissa, Selim;

    2014-01-01

    , 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...

  9. Evaluating exposures to complex mixtures of chemicals during a new production process in the plastics industry

    NARCIS (Netherlands)

    Meijster, T.; Burstyn, I.; Wendel de Joode, B. van; Posthumus, M.A.; Kromhout, H.

    2004-01-01

    The goal of this study was to monitor emission of chemicals at a factory where plastics products were fabricated by a new robotic (impregnated tape winding) production process. Stationary and personal air measurements were taken to determine which chemicals were released and at what concentrations.

  10. Chemical Effects of Nuclear Transformations Vol. I. Proceedings of the Symposium on Chemical Effects Associated with Nuclear Reactions and Radioactive Transformations

    International Nuclear Information System (INIS)

    The study of the chemical changes consequent upon the nuclear transformation of an atom that is linked with other atoms in a molecule and surrounded by other similar or dissimilar molecules has intrigued chemists for a number of years. This interest is certainly not static but if anything is increasing. The main theme of this meeting was a discussion of the suggestions and theories that have been advanced to explain the wealth of experimental observations on the behaviour of atoms at energies and in situations not normally accessible in the laboratory. Though the subject has some practical implications in the preparation of radioisotopes, this was not an important consideration at this Symposium. The first Symposium on hot-atom chemistry organized by the Agency was held in Prague in October 1960. Comparison of the past and the present state of the subject shows that a greater variety and sophistication of techniques are now being applied as the simpler approaches used in the past have been shown to be inadequate. Progress has been made in the understanding of the simpler gas system, but in liquids and solids there is still much to clarify. It is also of interest that for the majority of the work reported in these Proceedings a reactor was the radiation source, and in this field much experimental work still remains to be done. The Symposium on Chemical Effects Associated with Nuclear Reactions and Radioactive Transformations was held from 7 to 11 December 1964 in Vienna, and was attended by 136 participants from 29 countries and 4 international organizations. It was organized by the International Atomic Energy Agency in co-operation with the Joint Commission on Applied Radioactivity. The publication of these Proceedings makes the content of the papers and discussion available to a wider audience than was possible at the meeting in Vienna

  11. Chemical Effects of Nuclear Transformations. Vol. II. Proceedings of the Symposium on Chemical Effects Associated with Nuclear Reactions and Radioactive Transformations

    International Nuclear Information System (INIS)

    The study of the chemical changes consequent upon the nuclear transformation of an atom that is linked with other atoms in a molecule and surrounded by other similar or dissimilar molecules has intrigued chemists for a number of years. This interest is certainly not static but if anything is increasing. The main theme of this meeting was a discussion of the suggestions and theories that have been advanced to explain the wealth of experimental observations on the behaviour of atoms at energies and in situations not normally accessible in the laboratory. Though the subject has some practical implications in the preparation of radioisotopes, this was not an important consideration at this Symposium. The first Symposium on hot-atom chemistry organized by the Agency was held in Prague in October 1960. Comparison of the past and the present state of the subject shows that a greater variety and sophistication of techniques are now being applied as the simpler approaches used in the past have been shown to be inadequate. Progress has been made in the understanding of the simpler gas system, but in liquids and solids there is still much to clarify. It is also of interest that for the majority of the work reported in these Proceedings a reactor was the radiation source, and in this field much experimental work still remains to be done. The Symposium on Chemical Effects Associated with Nuclear Reactions and Radioactive Transformations was held from 7 to 11 December 1964 in Vienna, and was attended by 136 participants from 29 countries and 4 international organizations. It was organized by the International Atomic Energy Agency in co-operation with the Joint Commission on Applied Radioactivity. The publication of these Proceedings makes the content of the papers and discussion available to a wider audience than was possible at the meeting in Vienna

  12. Chemical and microbiological assessments of the multi mixture treated by gamma radiation

    International Nuclear Information System (INIS)

    In Brazil, the multi mixture have being used since the eighties as an alternative against severe infantile malnutrition of the poorest population. However, its use is still reason of controversies mainly due to: the presence of anti nutritional factors, the microbiological quality and the nutritional value. Considering the routine use of multi mixture in the region, this work aimed to evaluate samples of multi mixture were collected in the metropolitan area of the City of Belo Horizonte/MG for determining the anti nutritional factors (phytic and oxalic acids), the microbiological quality, the centesimal and mineral composition, and still the induced effect in these factors of the gamma radiation. For the analyses, the samples passed by the process of gamma irradiation at doses of: 2, 4, 6, 8 and 10 kGy and then were evaluated anti nutritional factors (phytic acid and oxalic), the microbiological quality (yeasts and molds, Salmonella, Coagulase positive Staphylococcus, Bacillus cereus, coliform to 45 deg C) to full percentage (moisture, ash, proteins, carbohydrates and lipids) and the efficiency of the method of Paramagnetic Electronic Resonance (EPR) in the detection of irradiated samples. The mineral composition of the samples was carried out by the irradiation by Neutronic Activation. The methods used were searched in literature. The obtained results suggest that the concentration of the phytic and oxalic acids can not be appropriated for the children with severe nutritional deficit and that it would be necessary additional control in their daily ingestion due to the absorption of essential minerals. In general the samples had presented acceptable microbiological quality for consumption, except by one of it. The data of the centesimal and mineral composition, in the usually recommended portions, showed lower concentration than recommended for children. Any significant alteration in phytic and oxalic acids as well as in the centesimal composition were detected

  13. A Study on Physical and Chemical Properties of Cellulose Paper Immersed in Various Solvent Mixtures

    OpenAIRE

    Mustafa Burak Arslan; Halil Turgut Sahin

    2008-01-01

    The cellulose paper treated in proportional mixture systems showed higher liquid absorption compare to only EtOH and MeOH treatments. It was approximately 40-70% and 50-91% higher for EtOH-NaOH and MeOH-NaOH treated papers, respectively. All conditions apparently bring about an effect of decreased strength for papers. The lowest tensile strength of 13.0 N/mm was found with EtOH and NaOH treated samples after 5th repeating wetting-drying stage. But, some conditions gave approximately 21-59.5% ...

  14. Purification of hydrogen under a free or combined form in a gaseous mixture, by chemical reactions with uranium

    International Nuclear Information System (INIS)

    Within the framework of the european fusion program, we are dealing with the purification of hydrogen (tritium) under a free or combined form, from a H2, N2, NH3, CH4, O2, gaseous mixture. The process consists in cracking the hydrogenated molecules and absorbing the impurities by chemical reactions with uranium, without holding back hydrogen. In the temperature range: 950 K < T < 1200 K hydrides are indeed fully decomposed for hydrogen partial pressures lower than ten atmospheres while uranium oxides, nitrides and carbides formation reactions are promoted. The experiments are carried out with massive uranium heated at 973 K in a closed reactor. They confirm that such a process may satisfy our goals, but they point out the importance of interactions occurring between the gaseous and solids systems and interfere with the conversion rates. Gaseous pressure decreases with time according to two successive phases: the first one is governed by a surface kinetic law, while after a short transition time, gas diffusion in the solid products arises and becomes the limiting step of the reactions. Experimental results with pure gases and mixtures, prove that solid products have different structures. An illustrative example is given by nitrogen and methane reactions with uranium: the solid layers are compactely formed with each pure gas and they slow down the chemical kinetic rates; on the contrary the chemical kinetic rates of the mixed gases reactions are clearly increased and the diffusional rates are postponed. Then, the compacity of the solid products merely depends on the operating conditions and the influence of the reactional surface state on the chemical kinetic rates is here pointed out

  15. Using biological and physico-chemical test methods to assess the role of concrete mixture design in resistance to microbially induced corrosion

    Science.gov (United States)

    House, Mitchell Wayne

    Concrete is the most widely used material for construction of wastewater collection, storage, and treatment infrastructure. The chemical and physical characteristics of hydrated portland cement make it susceptible to degradation under highly acidic conditions. As a result, some concrete wastewater infrastructure may be susceptible to a multi-stage degradation process known as microbially induced corrosion, or MIC. MIC begins with the production of aqueous hydrogen sulfide (H2S(aq)) by anaerobic sulfate reducing bacteria present below the waterline. H2S(aq) partitions to the gas phase where it is oxidized to sulfuric acid by the aerobic sulfur oxidizing bacteria Thiobacillus that resides on concrete surfaces above the waterline. Sulfuric acid then attacks the cement paste portion of the concrete matrix through decalcification of calcium hydroxide and calcium silica hydrate coupled with the formation of expansive corrosion products. The attack proceeds inward resulting in reduced service life and potential failure of the concrete structure. There are several challenges associated with assessing a concrete's susceptibility to MIC. First, no standard laboratory tests exist to assess concrete resistance to MIC. Straightforward reproduction of MIC in the laboratory is complicated by the use of microorganisms and hydrogen sulfide gas. Physico-chemical tests simulating MIC by immersing concrete specimens in sulfuric acid offer a convenient alternative, but do not accurately capture the damage mechanisms associated with biological corrosion. Comparison of results between research studies is difficult due to discrepancies that can arise in experimental methods even if current ASTM standards are followed. This thesis presents two experimental methods to evaluate concrete resistance to MIC: one biological and one physico-chemical. Efforts are made to address the critical aspects of each testing method currently absent in the literature. The first method presented is a new test

  16. Comparison of diamond growth with different gas mixtures in microwave plasma asssited chemical vapor deposition (MWCVD

    Directory of Open Access Journals (Sweden)

    Evaldo J. Corat

    2003-01-01

    Full Text Available In this work we study the influence of oxygen addition to several halocarbon-hydrogen gas systems. Diamond growth have been performed in a high power density MWCVD reactor built in our laboratory. The growth experiments are monitored by argon actinometry as a reference to plasma temperature and atomic hydrogen production, and by mass spectrometry to compare the exhaust gas composition. Atomic hydrogen actinometry revealed that the halogen presence in the gas phase is responsible for a considerable increase of atomic hydrogen concentration in the gas phase. Mass spectrometry shows similar results for all gas mixtures tested. Growth studies with oxygen addition to CF4/H2, CCl4/H2, CCl2F2/H2 and CH3Cl/H2 reveals that oxygen increases the carbon solubility in the gas phase but no better diamond growth conditions were found. Halogens are not, per se, eligible for diamond growth. All the possible advantages, as the higher production of atomic hydrogen, have been suppressed by the low carbon solubility in the gas phase, even when oxygen is added. The diamond growth with small amount of CF4 added to CH4/H2 mixture is not aggressive to the apparatus but brings several advantages to the process.

  17. 49. Meeting of the Chemical Societies: Proceedings of the contributions. Vol. 2

    International Nuclear Information System (INIS)

    The publication has been set up as a abstracts of the meeting dealing with chemical problems. The book (Vol. 2) consists of the sections: (C) Physical chemistry; (D) History of the chemistry; (E) Food chemistry and technology; (D) Environmental chemistry; (E) Nuclear chemistry and radioecology; (H) Synthetic polymers

  18. Access and use of information resources in assessing health risks from chemical exposure: Proceedings

    International Nuclear Information System (INIS)

    Health risk assessment is based on access to comprehensive information about potentially hazardous agents in question. Relevant information is scattered throughout the literature, and often is not readily accessible. To be useful in assessment efforts, emerging scientific findings, risk assess parameters, and associated data must be compiled and evaluated systemically. The US Environmental Protection Agency (EPA) and Oak Ridge National Laboratory (ORNL) are among the federal agencies heavily involved in this effort. This symposium was a direct response by EPA and ORNL to the expressed needs of individuals involved in assessing risks from chemical exposure. In an effort to examine the state of the risk assessment process, the availability of toxicological information, and the future development and transfer of this information, the symposium provided an excellent cadre of speakers and participants from state and federal agencies, academia and research laboratories to address these topics. This stimulating and productive gathering discussed concerns associated with (1) environmental contamination by chemicals; (2) laws regulating chemicals; (3) information needs and resources; (4) applications; (5) challenges and priorities; and (6)future issues. Individual reports are processed separately for the data bases

  19. Access and use of information resources in assessing health risks from chemical exposure: Proceedings

    Energy Technology Data Exchange (ETDEWEB)

    1990-12-31

    Health risk assessment is based on access to comprehensive information about potentially hazardous agents in question. Relevant information is scattered throughout the literature, and often is not readily accessible. To be useful in assessment efforts, emerging scientific findings, risk assess parameters, and associated data must be compiled and evaluated systemically. The US Environmental Protection Agency (EPA) and Oak Ridge National Laboratory (ORNL) are among the federal agencies heavily involved in this effort. This symposium was a direct response by EPA and ORNL to the expressed needs of individuals involved in assessing risks from chemical exposure. In an effort to examine the state of the risk assessment process, the availability of toxicological information, and the future development and transfer of this information, the symposium provided an excellent cadre of speakers and participants from state and federal agencies, academia and research laboratories to address these topics. This stimulating and productive gathering discussed concerns associated with (1) environmental contamination by chemicals; (2) laws regulating chemicals; (3) information needs and resources; (4) applications; (5) challenges and priorities; and (6)future issues. Individual reports are processed separately for the data bases.

  20. 76 FR 41371 - Impact of Reducing the Mixture Concentration Threshold for Commercial Schedule 3 Chemical...

    Science.gov (United States)

    2011-07-13

    ... comments on the impact of amending the Chemical Weapons Convention Regulations (CWCR) to reduce the... Implementation Act (CWCIA). Accordingly, publication and implementation of regulatory changes affecting this low... Act of 1995 (44 U.S.C. 3501 et seq.) (PRA). Notwithstanding any other provision of law, no person...

  1. Supramolecular chemical shift reagents inducing conformational transitions: NMR analysis of carbohydrate homooligomer mixtures

    DEFF Research Database (Denmark)

    Beeren, Sophie; Meier, Sebastian

    2015-01-01

    We introduce the concept of supramolecular chemical shift reagents as a tool to improve signal resolution for the NMR analysis of homooligomers. Non-covalent interactions with the shift reagent can constrain otherwise flexible analytes inducing a conformational transition that results in signal...

  2. Application of four bacterial screening procedures to assess changes in the toxicity of chemicals in mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Dutka, B.J.; Kwan, K.K.

    1982-10-01

    Four microbiological acute toxicity screening test methods with Microtox, Spirillum volutans, Pseudomonas fluorescens and Aeromonas hydrophila were compared using solutions of mixed toxic chemicals. Each toxicity screening test appeared to have its own sensitivity pattern and it would appear unwise to try to assess the presence of toxicants in waters or effluents by a single species test. The battery approach, encompassing two or three genera and involving two to four species, is recommended to assess the potential presence of toxicants more thoroughly.

  3. Structural Consequences of Duplicitous Chemical Relation of Cobalt and Fullerene in Mixture

    Czech Academy of Sciences Publication Activity Database

    Lavrentiev, Vasyl; Vacík, Jiří; Naramoto, H.

    2012-01-01

    Roč. 20, 4-7 (2012), s. 328-335. ISSN 1536-383X R&D Projects: GA AV ČR(CZ) KAN400480701; GA ČR GA106/09/1264; GA ČR GAP107/11/1856 Institutional support: RVO:61389005 Keywords : fullerene * cobalt * chemical bonding * nanostructure * self- organization Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 0.764, year: 2012

  4. Proceedings of the sixty third annual session of Indian Institute of Chemical Engineers: souvenir

    International Nuclear Information System (INIS)

    Biotechnology is on a wide range of industrial agenda covering fine chemicals, bulk chemicals, pharmaceuticals food, textiles, pulps, paper, mineral and energy areas paving the way of an industrial revolution in the 21st century. Broadly, industrial applications face different economic pressures as 'green', 'red' and 'white'. While 'green' biotechnology's agricultural applications emerge from millennia of human selective breeding of animals and plants, 'red' applications draw their lineage back to the healing arts 'white' include new and emerging non-medical and non-agricultural applications. Fuels produced using bio-technology such as bioethanol and bio-diesel are all potential oil replacement. Thus bio-technology is proving its worth as a technology that can contribute to sustainable industrial development. Many bio-catalytic tools are rapidly becoming available for industrial applications because of the recent advances in this technique. The present conference will enable the researchers and industrialists to exchange their ideas and rejuvenate their bio-technological skills aiming towards industrial sustainability. Papers relevant to INIS are indexed separately

  5. A Study on Physical and Chemical Properties of Cellulose Paper Immersed in Various Solvent Mixtures

    Directory of Open Access Journals (Sweden)

    Mustafa Burak Arslan

    2008-01-01

    Full Text Available The cellulose paper treated in proportional mixture systems showed higher liquid absorption compare to only EtOH and MeOH treatments. It was approximately 40-70% and 50-91% higher for EtOH-NaOH and MeOH-NaOH treated papers, respectively. All conditions apparently bring about an effect of decreased strength for papers. The lowest tensile strength of 13.0 N/mm was found with EtOH and NaOH treated samples after 5th repeating wetting-drying stage. But, some conditions gave approximately 21-59.5% higher stretch than untreated samples. The pore size distributions of papers were evaluated with Simons stain procedure and experimental results usually consisted with sorption data. The less intense CH2-CH2- vibrations (1450-1700 cm-1 and C-C and C-O-C peak areas in FTIR spectra indicates lowering H-bonds in solvent treated and dried paper network structure.

  6. Application of the Maximum Entropy Principle in the Analysis of a Non-Equilibrium Chemically Reacting Mixture

    Directory of Open Access Journals (Sweden)

    Hameed Metghalchi

    2005-03-01

    Full Text Available The Maximum Entropy Principle has been used to model complex chemical reaction processes. The maximum entropy principle has been employed by the Rate-Controlled Constrained-Equilibrium (RCCE method to determine concentration of different species during non-equilibrium combustion process. In this model, it is assumed that the system evolves through constrained equilibrium states where entropy of the mixture is maximized subject to constraints. Mixture composition is determined by integrating set of differential equations of constraints rather than integration of differential equations for species as is done with detailed kinetics techniques. Since the number of constraints is much smaller than the number of species present, the number of rate equations required to describe the time evolution of the system is considerably reduced. This method has been used to model the stoichiometric mixture of the formaldehyde-oxygen combustion process. In this study 29 species and 139 reactions has been used, while keeping the energy and volume of the system constant. Calculations have been done at different sets of pressures and temperatures, ranging from 1 atm to 100 atm, and from 900 K to 1500 K respectively. Three fixed elemental constraints: conservation of elemental carbon, elemental oxygen and elemental hydrogen and from one to six variable constraints were used. The four to nine rate equations for the constraint potentials (Lagrange multipliers conjugate to the constraints were integrated and as expected, RCCE calculations gave correct equilibrium values in all cases. Only 8 constraints were required to give very good agreement with detailed calculations. Ignition delay times and major species concentrations were within 0.5% to 5% of the values predicted by detailed chemistry calculations. Adding more constraints improved the accuracy of the mole fractions of minor species at early times, but had only a little effect on the ignition delay times. Rate

  7. Conversion of the chemical concentration of odorous mixtures into odour concentration and odour intensity: A comparison of methods

    Science.gov (United States)

    Wu, Chuandong; Liu, Jiemin; Zhao, Peng; Piringer, Martin; Schauberger, Günther

    2016-02-01

    Continuous odour measurements both of emissions as well as ambient concentrations are seldom realised, mainly because of their high costs. They are therefore often substituted by concentration measurements of odorous substances. Then a conversion of the chemical concentrations C (mg m-3) into odour concentrations COD (ouE m-3) and odour intensities OI is necessary. Four methods to convert the concentrations of single substances to the odour concentrations and odour intensities of an odorous mixture are investigated: (1) direct use of measured concentrations, (2) the sum of the odour activity value SOAV, (3) the sum of the odour intensities SOI, and (4) the equivalent odour concentration EOC, as a new method. The methods are evaluated with olfactometric measurements of seven substances as well as their mixtures. The results indicate that the SOI and EOC conversion methods deliver reliable values. These methods use not only the odour threshold concentration but also the slope of the Weber-Fechner law to include the sensitivity of the odour perception of the individual substances. They fulfil the criteria of an objective conversion without the need of a further calibration by additional olfactometric measurements.

  8. The capric and lauric acid mixture with chemical additives as latent heat storage materials for cooling application

    Energy Technology Data Exchange (ETDEWEB)

    Roxas-Dimaano, M.N. [University of Santo Tomas, Manila (Philippines). Research Center for the Natural Sciences; Watanabe, T. [Tokyo Institute of Technology (Japan). Research Laboratory for Nuclear Reactors

    2002-09-01

    The mixture of capric acid and lauric acid (C-L acid), with the respective mole composition of 65% and 35%, is a potential phase change material (PCM). Its melting point of 18.0{sup o}C, however, is considered high for cooling application of thermal energy storage. The thermophysical and heat transfer characteristics of the C-L acid with some organic additives are investigated. Compatibility of C-L acid combinations with additives in different proportions and their melting characteristics are analyzed using the differential scanning calorimeter (DSC). Among the chemical additives, methyl salicylate, eugenol, and cineole presented the relevant melting characteristics. The individual heat transfer behavior and thermal storage performance of 0.1 mole fraction of these additives in the C-L acid mixture are evaluated. The radial and axial temperature distribution during charging and discharging at different concentrations of selected PCM combinations are experimentally determined employing a vertical cylindrical shell and tube heat exchanger. The methyl salicylate in the C-L acid provided the most effective additive in the C-L acid. It demonstrated the least melting band width aimed at lowering the melting point of the C-L acid with the highest heat of fusion value with relatively comparable rate of heat transfer. Furthermore, the thermal performance based on the total amount of transferred energy and their rates, established the PCM's latent heat storage capability. (author)

  9. Parameters, limits, attenuation, and suppression of detonation in mixtures of an explosive gas with chemically inert microparticles

    Science.gov (United States)

    Fedorov, A. V.; Fomin, P. A.; Tropin, D. A.; Chen, Z.-R.

    2012-03-01

    Chapman-Jouguet parameters and the cell size of a detonation wave in mixtures of an explosive gas with chemically inert particles have been calculated. The algorithm of calculation of the minimum mass and characteristic dimension of a particle cloud ensuring successful suppression of detonation in the gas has been proposed. The calculation results are in good agreement with the available experimental data. The influence of the initial composition of the gas on the efficiency of suppression of the detonation wave has been analyzed. The issue of the dependence of the concentration limits of detonation on the mass fraction of particles has been investigated. It has been established that the increase in the concentration of the condensed phase leads to a narrowing of the existence domain of detonation and that the propagation of the detonation wave becomes impossible when the concentration of the particles is fairly high.

  10. Novel process and catalytic materials for converting CO2 and H2 containing mixtures to liquid fuels and chemicals.

    Science.gov (United States)

    Meiri, Nora; Dinburg, Yakov; Amoyal, Meital; Koukouliev, Viatcheslav; Nehemya, Roxana Vidruk; Landau, Miron V; Herskowitz, Moti

    2015-01-01

    Carbon dioxide and water are renewable and the most abundant feedstocks for the production of chemicals and fungible fuels. However, the current technologies for production of hydrogen from water are not competitive. Therefore, reacting carbon dioxide with hydrogen is not economically viable in the near future. Other alternatives include natural gas, biogas or biomass for the production of carbon dioxide, hydrogen and carbon monoxide mixtures that react to yield chemicals and fungible fuels. The latter process requires a high performance catalyst that enhances the reverse water-gas-shift (RWGS) reaction and Fischer-Tropsch synthesis (FTS) to higher hydrocarbons combined with an optimal reactor system. Important aspects of a novel catalyst, based on a Fe spinel and three-reactor system developed for this purpose published in our recent paper and patent, were investigated in this study. Potassium was found to be a key promoter that improves the reaction rates of the RWGS and FTS and increases the selectivity of higher hydrocarbons while producing mostly olefins. It changed the texture of the catalyst, stabilized the Fe-Al-O spinel, thus preventing decomposition into Fe3O4 and Al2O3. Potassium also increased the content of Fe5C2 while shifting Fe in the oxide and carbide phases to a more reduced state. In addition, it increased the relative exposure of carbide iron on the catalysts surface, the CO2 adsorption and the adsorption strength. A detailed kinetic model of the RWGS, FTS and methanation reactions was developed for the Fe spinel catalyst based on extensive experimental data measured over a range of operating conditions. Significant oligomerization activity of the catalyst was found. Testing the pelletized catalyst with CO2, CO and H2 mixtures over a range of operating conditions demonstrated its high productivity to higher hydrocarbons. The composition of the liquid (C5+) was found to be a function of the potassium content and the composition of the feedstock

  11. Numerical modelling of shock-induced chemical reactions (SICR) in reactive powder mixtures using smoothed particle hydrodynamics (SPH)

    Science.gov (United States)

    S, Siva Prasad A. V.; Basu, Sumit

    2015-10-01

    Shock compaction of reactive powder mixtures to synthesize new materials is one of the oldest material processing techniques and has been studied extensively by several researchers over the past few decades. The quantitative connection between the shock energy imparted and the extent of reaction that can be completed in the small time window associated with the passage of the shock wave is complicated and depends on a large variety of parameters. In particular, our understanding of the complex interplay between the thermo-elasto-viscoplastic behaviour of the granular constituents and their temperature dependent, diffusion-limited reaction mechanism may be enriched through careful numerical simulations. A robust numerical model should be able to handle extremely large deformations coupled with diffusion mediated fast reaction kinetics. In this work, a meshfree discrete particle numerical method based on smoothed particle hydrodynamics (SPH) to simulate shock-induced chemical reactions (SICR) in reactive powder mixtures is proposed. We present a numerical strategy to carry out reactions between reactant powder particles and partition the obtained products between the particles in a manner that accounts for the requirement that the total mass of the entire system remains constant as the reactions occur. Instead of solving the reaction-diffusion problem, we propose a ‘pseudo-diffusion’ model in which a distance dependent reaction rate constant is defined to carry out chemical reaction kinetics. This approach mimics the actual reaction-diffusion process at short times. Our numerical model is demonstrated for the well-studied reaction system Nb  +  2Si \\rightleftharpoons NbSi 2 . The predicted mass fractions of the product obtained from the simulations are in agreement with experimental observations. Finally, the effects of impact speed, particle arrangement and mixing ratio on the predicted product mass fractions are discussed.

  12. Contaminant mixtures and repoductive health: Developmental toxicity effects in rats after mixed exposure to environmentally relevant endocrine disrupting chemicals, with focus on effects in females

    DEFF Research Database (Denmark)

    Jacobsen, Pernille Rosenskjold; Christiansen, Sofie; Hass, Ulla

    effects in females both early and later in life. Methods: The results, presented in this thesis, were obtained in five developmental toxicology studies. Two studies investigated mixtures of endocrine disrupting pesticides (Pestimix), two investigated mixtures of endocrine disrupting chemicals based...... on human exposures (Contamed), and one study tested a positive control for estrogenic effects, ethinyl estradiol (EE2). The project with the mixture of the five pesticides included two range-finding studies (collectively called Pestimix RF) and a dose response study (Pestimix DR). In the Contamed project...... chemicals included phthalates, pesticides, UV-filters, bisphenol A, parabens and the drug paracetamol. Together the chemicals represented several modes of action with regard to endocrine disrupting mode of action. Finally, results from a dose response study on the estrogenic drug EE2 were included. In all...

  13. Specific interactions of functionalised gold surfaces with ammonium perchlorate or starch; towards a chemical cartography of their mixture

    Science.gov (United States)

    Mercier, D.; Mercader, C.; Quere, S.; Hairault, L.; Méthivier, C.; Pradier, C. M.

    2012-10-01

    By functionalising gold samples, planar wafers or AFM tips, with an acid- or an amino acid-terminated thiols, mercaptoundecanoic acid (MUA) and homocystein (H-Cyst) respectively, we were able to differentiate the interactions with ammonium perchlorate (AP) and starch (S), two components of a nanocomposition mixture. To do so, the interaction between gold functionalized surfaces and the two targeted compounds have been characterized and quantified by several complementary techniques. Polarisation modulation-infrared spectroscopy (PM-IRRAS), and X-ray photoelectron spectroscopy (XPS), providing chemical analyses of gold surfaces after contacting S or AP, proved that both compounds were retained on MUA or H-Cyst-modified surfaces, but to various extents. Quartz crystal microbalance on-line measurements enabled to monitor the kinetics of interaction and showed distinct differences in the behaviour of MUA and H-Cyst-surfaces towards the two compounds. Having observed that only H-Cyst-modified surfaces enables to get a contrast on the chemical force microscopy (CFM) images, this new result could be well explained by examining the data obtained by combining the above-mentioned surface characterisation techniques.

  14. Specific interactions of functionalised gold surfaces with ammonium perchlorate or starch; towards a chemical cartography of their mixture

    Energy Technology Data Exchange (ETDEWEB)

    Mercier, D. [CNRS, UMR CNRS 7609, Laboratoire de Reactivite de Surface, Paris (France); Universite Pierre et Marie Curie - UPMC Paris VI, Laboratoire de Reactivite de Surface, 4 place Jussieu, 75252 Paris Cedex 05 (France); Laboratoire de recherche conventionne CEA/UPMC n Degree-Sign 1, Paris (France); Mercader, C.; Quere, S.; Hairault, L. [CEA, DAM, Le Ripault, F-37260 Monts (France); Laboratoire de recherche conventionne CEA/UPMC n Degree-Sign 1, Paris (France); Methivier, C. [CNRS, UMR CNRS 7609, Laboratoire de Reactivite de Surface, Paris (France); Universite Pierre et Marie Curie - UPMC Paris VI, Laboratoire de Reactivite de Surface, 4 place Jussieu, 75252 Paris Cedex 05 (France); Laboratoire de recherche conventionne CEA/UPMC n Degree-Sign 1, Paris (France); Pradier, C.M., E-mail: claire-Marie.pradier@upmc.fr [CNRS, UMR CNRS 7609, Laboratoire de Reactivite de Surface, Paris (France); Universite Pierre et Marie Curie - UPMC Paris VI, Laboratoire de Reactivite de Surface, 4 place Jussieu, 75252 Paris Cedex 05 (France); Laboratoire de recherche conventionne CEA/UPMC n Degree-Sign 1, Paris (France)

    2012-10-01

    Highlights: Black-Right-Pointing-Pointer Measurements of interactions by Quartz Crystal Microbalance. Black-Right-Pointing-Pointer AFM and CFM measurements, tip functionalisation. Black-Right-Pointing-Pointer Surface nano-imaging. - Abstract: By functionalising gold samples, planar wafers or AFM tips, with an acid- or an amino acid-terminated thiols, mercaptoundecanoic acid (MUA) and homocystein (H-Cyst) respectively, we were able to differentiate the interactions with ammonium perchlorate (AP) and starch (S), two components of a nanocomposition mixture. To do so, the interaction between gold functionalized surfaces and the two targeted compounds have been characterized and quantified by several complementary techniques. Polarisation modulation-infrared spectroscopy (PM-IRRAS), and X-ray photoelectron spectroscopy (XPS), providing chemical analyses of gold surfaces after contacting S or AP, proved that both compounds were retained on MUA or H-Cyst-modified surfaces, but to various extents. Quartz crystal microbalance on-line measurements enabled to monitor the kinetics of interaction and showed distinct differences in the behaviour of MUA and H-Cyst-surfaces towards the two compounds. Having observed that only H-Cyst-modified surfaces enables to get a contrast on the chemical force microscopy (CFM) images, this new result could be well explained by examining the data obtained by combining the above-mentioned surface characterisation techniques.

  15. BEHAVIOR OF SURFACTANT MIXTURES AT SOLID/LIQUID AND OIL/LIQUID INTERFACES IN CHEMICAL FLOODING SYSTEMS

    Energy Technology Data Exchange (ETDEWEB)

    P. Somasundaran

    2004-11-20

    The aim of the project is to develop a knowledge base to help the design of enhanced processes for mobilizing and extracting untrapped oil. We emphasize evaluation of novel surfactant mixtures and obtaining optimum combinations of the surfactants for efficient chemical flooding EOR processes. In this regard, an understanding of the aggregate shape, size and structure is crucial since these properties govern the crude oil removal efficiency. During the three-year period, the adsorption and aggregation behavior of sugar-based surfactants and their mixtures with other types of surfactants have been studied. Sugar-based surfactants are made from renewable resources, nontoxic and biodegradable. They are miscible with water and oil. These environmentally benign surfactants feature high surface activity, good salinity, calcium and temperature tolerance, and unique adsorption behavior. They possess the characteristics required for oil flooding surfactants and have the potential for replacing currently used surfactants in oil recovery. A novel analytical ultracentrifugation technique has been successfully employed for the first time, to characterize the aggregate species present in mixed micellar solution due to its powerful ability to separate particles based on their size and shape and monitor them simultaneously. Analytical ultracentrifugation offers an unprecedented opportunity to obtain important information on mixed micelles, structure-performance relationship for different surfactant aggregates in solution and their role in interfacial processes. Initial sedimentation velocity investigations were conducted using nonyl phenol ethoxylated decyl ether (NP-10) to choose the best analytical protocol, calculate the partial specific volume and obtain information on sedimentation coefficient, aggregation mass of micelles. Four softwares: OptimaTM XL-A/XL-I data analysis software, DCDT+, Svedberg and SEDFIT, were compared for the analysis of sedimentation velocity

  16. BEHAVIOR OF SURFACTANT MIXTURE AT SOLID/LIQUID AND OIL/LIQUID INTERFACE IN CHEMICAL FLOODING SYSTEMS

    Energy Technology Data Exchange (ETDEWEB)

    Prof. P. Somasundaran

    2002-03-01

    The aim of the project is to develop and evaluate efficient novel surfactant mixtures for enhanced oil recovery. Preliminary ultra-filtration tests suggest that two kinds of micelles may exist in binary surfactant mixtures at different concentrations. Due to the important role played in interfacial processes by micelles as determined by their structures, focus of the current work is on the delineation of the relationship between such aggregate structures and chemical compositions of the surfactants. A novel analytical centrifuge application is explored to generate information on structures of different surfactants aggregates. In this report, optical systems, typical output of the analytical ultracentrifuge results and four basic experiments are discussed. Initial sedimentation velocity investigations were conducted using nonyl phenol ethoxylated decyl ether (NP-10) to choose the best analytical protocol, calculate the partial specific volume and obtain information on sedimentation coefficient, aggregation mass of micelles. The partial specific volume was calculated to be 0.920. Four softwares: Optima{trademark} XL-A/XL-I data analysis software, DCDT+, Svedberg and SEDFIT, were compared for the analysis of sedimentation velocity experimental data. The sedimentation coefficient and aggregation number of NP-10 micelles obtained using the first three softwares at 25 C are 209, 127, and 111, respectively. The last one is closest to the result from Light Scattering. The reason for the differences in numbers obtained using the three softwares is discussed. Based on these tests, Svedberg and SEDFIT analysis are chosen for further studies. This approach using the analytical ultracentrifugation offers an unprecedented opportunity now to obtain important information on mixed micelles and their role in interfacial processes.

  17. Design Concepts for Co-Production of Power, Fuels & Chemicals Via Coal/Biomass Mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Rao, A. D.; Chen, Q.; Samuelsen, G. S.

    2012-09-30

    The overall goal of the program is to develop design concepts, incorporating advanced technologies in areas such as oxygen production, feed systems, gas cleanup, component separations and gas turbines, for integrated and economically viable coal and biomass fed gasification facilities equipped with carbon capture and storage for the following scenarios: (i) coproduction of power along with hydrogen, (ii) coproduction of power along with fuels, (iii) coproduction of power along with petrochemicals, and (iv) coproduction of power along with agricultural chemicals. To achieve this goal, specifically the following objectives are met in this proposed project: (i) identify advanced technology options and innovative preliminary design concepts that synergistically integrate plant subsections, (ii) develop steady state system simulations to predict plant efficiency and environmental signature, (iii) develop plant cost estimates by capacity factoring major subsystems or by major equipment items where required, and then capital, operating and maintenance cost estimates, and (iv) perform techno- economic analyses for the above described coproduction facilities. Thermal efficiencies for the electricity only cases with 90% carbon capture are 38.26% and 36.76% (HHV basis) with the bituminous and the lignite feedstocks respectively. For the coproduction cases (where 50% of the energy exported is in the form of electricity), the electrical efficiency, as expected, is highest for the hydrogen coproduction cases while lowest for the higher alcohols (ethanol) coproduction cases. The electrical efficiencies for Fischer-Tropsch coproduction cases are slightly higher than those for the methanol coproduction cases but it should be noted that the methanol (as well as the higher alcohol) coproduction cases produce the finished coproduct while the Fischer-Tropsch coproduction cases produce a coproduct that requires further processing in a refinery. The cross comparison of the thermal

  18. Proceedings of the 8th workshop on plant mutation breeding. Effective use of physical/chemical mutagens

    Energy Technology Data Exchange (ETDEWEB)

    Kume, Tamikazu; Watanabe, Kazuo; Tano, Shigemitsu (eds.) [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment

    2001-03-01

    The Workshop on Plant Mutation Breeding of FNCA (Forum for Nuclear Cooperation in Asia), was held on 9-13 October 2000 in Hanoi, Vietnam. The Workshop was co-sponsored by the Science and Technology Agency (STA), the Ministry of Science, Technology and Environment (MOSTE of Vietnam) and the Ministry of Agriculture and Rural Development (MARD of Vietnam) in cooperation with the Ministry of Agriculture, Forestry and Fisheries (MAFF), National Institute of Agrobiological Resources (NIAR of Vietnam), the Japan Atomic Industrial Forum (JAIF) and Japan Atomic Energy Research Institute (JAERI). Two Scientists, a Project Leader and an expert on methodology for plant/crop mutation breeding, participated from each of the member countries, i.e. China, Indonesia, Malaysia, the Philippines, Thailand, Vietnam and Japan. Also attending the Workshop were, one participant from Korea, seven participants from both Japan and Vietnam. The number of the participants in the Workshop totalled about sixty people including guests and observers. Sixteen papers including eight invited papers on the current status of methodology for plant/crop mutation breeding in the participating countries were presented. Discussions were focused on the subject concerning 'Effective Use of Physical/Chemical Mutagens', as well as a detailed report on the current status of research in each participating country. In addition, the topics of developing a mutant breeding database, an information exchange for plant/crop mutation breeding, and more tightly bound international co-operative research in the near future were also high on the agenda. This proceeding compiles the invited and contributed papers that were submitted from the speakers. (author)

  19. Proceedings of the 8th workshop on plant mutation breeding. Effective use of physical/chemical mutagens

    International Nuclear Information System (INIS)

    The Workshop on Plant Mutation Breeding of FNCA (Forum for Nuclear Cooperation in Asia), was held on 9-13 October 2000 in Hanoi, Vietnam. The Workshop was co-sponsored by the Science and Technology Agency (STA), the Ministry of Science, Technology and Environment (MOSTE of Vietnam) and the Ministry of Agriculture and Rural Development (MARD of Vietnam) in cooperation with the Ministry of Agriculture, Forestry and Fisheries (MAFF), National Institute of Agrobiological Resources (NIAR of Vietnam), the Japan Atomic Industrial Forum (JAIF) and Japan Atomic Energy Research Institute (JAERI). Two Scientists, a Project Leader and an expert on methodology for plant/crop mutation breeding, participated from each of the member countries, i.e. China, Indonesia, Malaysia, the Philippines, Thailand, Vietnam and Japan. Also attending the Workshop were, one participant from Korea, seven participants from both Japan and Vietnam. The number of the participants in the Workshop totalled about sixty people including guests and observers. Sixteen papers including eight invited papers on the current status of methodology for plant/crop mutation breeding in the participating countries were presented. Discussions were focused on the subject concerning 'Effective Use of Physical/Chemical Mutagens', as well as a detailed report on the current status of research in each participating country. In addition, the topics of developing a mutant breeding database, an information exchange for plant/crop mutation breeding, and more tightly bound international co-operative research in the near future were also high on the agenda. This proceeding compiles the invited and contributed papers that were submitted from the speakers. (author)

  20. PACKAGE (Plasma Analysis, Chemical Kinetics and Generator Efficiency): a computer program for the calculation of partial chemical equilibrium/partial chemical rate controlled composition of multiphased mixtures under one dimensional steady flow

    Energy Technology Data Exchange (ETDEWEB)

    Yousefian, V.; Weinberg, M.H.; Haimes, R.

    1980-02-01

    The NASA CEC Code was the starting point for PACKAGE, whose function is to evaluate the composition of a multiphase combustion product mixture under the following chemical conditions: (1) total equilibrium with pure condensed species; (2) total equilibrium with ideal liquid solution; (3) partial equilibrium/partial finite rate chemistry; and (4) fully finite rate chemistry. The last three conditions were developed to treat the evolution of complex mixtures such as coal combustion products. The thermodynamic variable pairs considered are either pressure (P) and enthalpy, P and entropy, at P and temperature. Minimization of Gibbs free energy is used. This report gives detailed discussions of formulation and input/output information used in the code. Sample problems are given. The code development, description, and current programming constraints are discussed. (DLC)

  1. Mixture effects at very low doses with combinations of anti-androgenic pesticides, antioxidants, industrial pollutant and chemicals used in personal care products

    International Nuclear Information System (INIS)

    Many xenobiotics have been identified as in vitro androgen receptor (AR) antagonists, but information about their ability to produce combined effects at low concentrations is missing. Such data can reveal whether joint effects at the receptor are induced at low levels and may support the prioritisation of in vivo evaluations and provide orientations for the grouping of anti-androgens in cumulative risk assessment. Combinations of 30 AR antagonists from a wide range of sources and exposure routes (pesticides, antioxidants, parabens, UV-filters, synthetic musks, bisphenol-A, benzo(a)pyrene, perfluorooctane sulfonate and pentabromodiphenyl ether) were tested using a reporter gene assay (MDA-kb2). Chemicals were combined at three mixture ratios, equivalent to single components' effect concentrations that inhibit the action of dihydrotesterone by 1%, 10% or 20%. Concentration addition (CA) and independent action were used to calculate additivity expectations. We observed complete suppression of dihydrotestosterone effects when chemicals were combined at individual concentrations eliciting 1%, 10% or 20% AR antagonistic effect. Due to the large number of mixture components, the combined AR antagonistic effects occurred at very low concentrations of individual mixture components. CA slightly underestimated the combined effects at all mixture ratios. In conclusion, large numbers of AR antagonists from a wide variety of sources and exposure routes have the ability of acting together at the receptor to produce joint effects at very low concentrations. Significant mixture effects are observed when chemicals are combined at concentrations that individually do not induce observable AR antagonistic effects. Cumulative risk assessment for AR antagonists should apply grouping criteria based on effects where data are available, rather than on criteria of chemical similarity. - Highlights: • Mixtures of AR antagonists at low individual concentrations cause complete inhibition

  2. Mixture effects at very low doses with combinations of anti-androgenic pesticides, antioxidants, industrial pollutant and chemicals used in personal care products

    Energy Technology Data Exchange (ETDEWEB)

    Orton, Frances; Ermler, Sibylle; Kugathas, Subramaniam [Institute for the Environment, Brunel University, Kingston Lane, Uxbridge UB8 3PH (United Kingdom); Rosivatz, Erika [Institute of Chemical Biology, Imperial College London, Exhibition Road, London SW7 2AZ (United Kingdom); Scholze, Martin [Institute for the Environment, Brunel University, Kingston Lane, Uxbridge UB8 3PH (United Kingdom); Kortenkamp, Andreas, E-mail: andreas.kortenkamp@brunel.ac.uk [Institute for the Environment, Brunel University, Kingston Lane, Uxbridge UB8 3PH (United Kingdom)

    2014-08-01

    Many xenobiotics have been identified as in vitro androgen receptor (AR) antagonists, but information about their ability to produce combined effects at low concentrations is missing. Such data can reveal whether joint effects at the receptor are induced at low levels and may support the prioritisation of in vivo evaluations and provide orientations for the grouping of anti-androgens in cumulative risk assessment. Combinations of 30 AR antagonists from a wide range of sources and exposure routes (pesticides, antioxidants, parabens, UV-filters, synthetic musks, bisphenol-A, benzo(a)pyrene, perfluorooctane sulfonate and pentabromodiphenyl ether) were tested using a reporter gene assay (MDA-kb2). Chemicals were combined at three mixture ratios, equivalent to single components' effect concentrations that inhibit the action of dihydrotesterone by 1%, 10% or 20%. Concentration addition (CA) and independent action were used to calculate additivity expectations. We observed complete suppression of dihydrotestosterone effects when chemicals were combined at individual concentrations eliciting 1%, 10% or 20% AR antagonistic effect. Due to the large number of mixture components, the combined AR antagonistic effects occurred at very low concentrations of individual mixture components. CA slightly underestimated the combined effects at all mixture ratios. In conclusion, large numbers of AR antagonists from a wide variety of sources and exposure routes have the ability of acting together at the receptor to produce joint effects at very low concentrations. Significant mixture effects are observed when chemicals are combined at concentrations that individually do not induce observable AR antagonistic effects. Cumulative risk assessment for AR antagonists should apply grouping criteria based on effects where data are available, rather than on criteria of chemical similarity. - Highlights: • Mixtures of AR antagonists at low individual concentrations cause complete inhibition

  3. Prediction of mixture toxicity from the hormesis of a single chemical: A case study of combinations of antibiotics and quorum-sensing inhibitors with gram-negative bacteria.

    Science.gov (United States)

    Wang, Ting; Wang, Dali; Lin, Zhifen; An, Qingqing; Yin, Chunsheng; Huang, Qinghui

    2016-05-01

    The 50% effect level of a single chemical in the real environment is almost impossible to determine at the low exposure concentration, and the prediction of the concentration of a mixture at the 50% effect level from the concentration of a single chemical at the low effect level is even more difficult. The current literature does not address this problem. Thus, to determine solutions for this question, single/mixture chronic toxicities of sulfonamides (SAs) and quorum-sensing inhibitors (QSIs) were determined using Gram-negative bacteria (Vibrio fischeri and E. coli.) and Gram-positive bacteria (B. subtilis) as the target organisms. The results showed that the joint effects of SAs and QSIs were primarily antagonistic responses. In addition, the toxicity mechanisms of mixtures of SAs and QSIs were investigated further, and the results revealed that the chronic joint effects were primarily an antagonistic response due to the QSI competing against acyl-homoserine lactones (AHL) for luxR in V. fischeri and SdiA in E. coli generated by the SAs, leading to negative effects exerted by the QSI-luxR or QSI-SdiA complexes on luxI in V. fischeri or FtsZ in E. coli. This phenomenon eventually weakened the stimulatory effect caused by the SAs. Based on the mixture toxicity mechanism, the relationship between the mixture toxicity and the simulation effect was formulated. PMID:26901472

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

    International Nuclear Information System (INIS)

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-10-01

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

  6. Proceedings of the Frontis Workshop on Chemical Ecology: from Gene to Ecosystem Wageningen, The Netherlands 19-23 March 2005

    NARCIS (Netherlands)

    Dicke, M.; Takken, W.

    2006-01-01

    Chemical ecology is the ecology of body odour. Every organism uses chemical information in intra- and interspecific interactions. Animals emit chemicals to attract a mate or to prevent a competitor from mating with the partner they just mated with. Plants emit chemicals to recruit other organisms to

  7. CEA contribution to the study of the long-term behaviour of cement mixtures: review of the different physico-chemical mechanisms of water alteration

    International Nuclear Information System (INIS)

    This work tries to give a synthetic overview of the physico-chemical alteration processes of a cement mixture by pure water. It is shown that the alteration kinetics is mainly controlled by two phenomena: the liquid phase diffusion of chemical species from the porous network towards the aggressive solution, and the dissolution of the material in contact with the aggressive solution. This work allows to evaluate the parameters involved in both phenomena and tries to evaluate the respective influence of diffusion and of surface dissolution on the damaging kinetics. (J.S.)

  8. Adverse Reproductive and Developmental Health Outcomes Following Prenatal Exposure to a Hydraulic Fracturing Chemical Mixture in Female C57Bl/6 Mice.

    Science.gov (United States)

    Kassotis, Christopher D; Bromfield, John J; Klemp, Kara C; Meng, Chun-Xia; Wolfe, Andrew; Zoeller, R Thomas; Balise, Victoria D; Isiguzo, Chiamaka J; Tillitt, Donald E; Nagel, Susan C

    2016-09-01

    Unconventional oil and gas operations using hydraulic fracturing can contaminate surface and groundwater with endocrine-disrupting chemicals. We have previously shown that 23 of 24 commonly used hydraulic fracturing chemicals can activate or inhibit the estrogen, androgen, glucocorticoid, progesterone, and/or thyroid receptors in a human endometrial cancer cell reporter gene assay and that mixtures can behave synergistically, additively, or antagonistically on these receptors. In the current study, pregnant female C57Bl/6 dams were exposed to a mixture of 23 commonly used unconventional oil and gas chemicals at approximately 3, 30, 300, and 3000 μg/kg·d, flutamide at 50 mg/kg·d, or a 0.2% ethanol control vehicle via their drinking water from gestational day 11 through birth. This prenatal exposure to oil and gas operation chemicals suppressed pituitary hormone concentrations across experimental groups (prolactin, LH, FSH, and others), increased body weights, altered uterine and ovary weights, increased heart weights and collagen deposition, disrupted folliculogenesis, and other adverse health effects. This work suggests potential adverse developmental and reproductive health outcomes in humans and animals exposed to these oil and gas operation chemicals, with adverse outcomes observed even in the lowest dose group tested, equivalent to concentrations reported in drinking water sources. These endpoints suggest potential impacts on fertility, as previously observed in the male siblings, which require careful assessment in future studies. PMID:27560547

  9. The influence of the "cage" effect on the mechanism of reversible bimolecular multistage chemical reactions proceeding from different sites in solutions.

    Science.gov (United States)

    Doktorov, Alexander B

    2016-08-28

    Manifestations of the "cage" effect at the encounters of reactants have been theoretically treated on the example of multistage reactions (including bimolecular exchange reactions as elementary stages) proceeding from different active sites in liquid solutions. It is shown that for reactions occurring near the contact of reactants, consistent consideration of quasi-stationary kinetics of such multistage reactions (possible in the framework of the encounter theory only) can be made on the basis of chemical concepts of the "cage complex," just as in the case of one-site model described in the literature. Exactly as in the one-site model, the presence of the "cage" effect gives rise to new channels of reactant transformation that cannot result from elementary event of chemical conversion for the given reaction mechanism. Besides, the multisite model demonstrates new (as compared to one-site model) features of multistage reaction course. PMID:27586911

  10. Steady detonation waves via the Boltzmann equation for a reacting mixture

    International Nuclear Information System (INIS)

    Based on the Boltzmann equation, the detonation problem is dealt with on a mesoscopic level. The model is based on the assumption that ahead of a shock an explosive gas mixture is in meta stable equilibrium. Starting from the Von Neumann point the chemical reaction, initiated by the pressure jump, proceeds until the chemical equilibrium is reached. Numerical solutions of the derived macroscopic equations as well as the corresponding Hugoniot diagrams which reveal the physical relevance of the mathematical model are provided

  11. Steady detonation waves via the Boltzmann equation for a reacting mixture

    CERN Document Server

    Conforto, F; Schürrer, F; Ziegler, I

    2003-01-01

    Based on the Boltzmann equation, the detonation problem is dealt with on a mesoscopic level. The model is based on the assumption that ahead of a shock an explosive gas mixture is in meta stable equilibrium. Starting from the Von Neumann point the chemical reaction, initiated by the pressure jump, proceeds until the chemical equilibrium is reached. Numerical solutions of the derived macroscopic equations as well as the corresponding Hugoniot diagrams which reveal the physical relevance of the mathematical model are provided.

  12. APTox: Assessment and Prediction on Toxicity of Chemical Mixtures%APTox:化学混合物毒性评估与预测

    Institute of Scientific and Technical Information of China (English)

    刘树深; 张瑾; 张亚辉; 覃礼堂

    2012-01-01

    真实环境中化学混合物的存在是普遍规律.化学混合物联合效应具有与单个组分不同的变化规律,目前缺少有效方法学与可靠基础数据.近年来,我们试图探索建立化学混合物毒性评估与预测(APTox)的方法体系.发展了微板毒性分析法(MTA)以提高测试数据精密度,创建了直接均分射线(EquRay)与均匀设计射线(UD-Ray)法来有效表征混合物浓度组成,建立了支持向量回归(SVR)技术拟合不同形状浓度-效应曲线,提出了将实验混合物整体剂量-效应曲线(CRC)与加和参考模型预测CRC比较以评价混合物毒性相互作用的方法,集成多种技术设计开发了化学混合物毒性评估与预测的应用程序.%In real environment, various chemicals are always existing as mixtures. The joint effect of a chemical mixture has different features from the components alone and it is not always predicted by the concentration-response information of pure components in the mixture. At present, there is no general approach and procedure for the estimation on the joint effect of a chemical mixture and neither credible fundamental data to develop novel methodology. In recent years, we developed the microplate toxicity analysis to improve the precision in the determination of toxicity data, created the direct equipartition ray to characterize the concentration composition of various binary mixtures and the uniform design ray to represent the concen- tration diversity in the real mixtures, built the support vector regression technique to model various shapes of different con- centration-response curves such as sigmoid curve and hormetic J-shaped curve, proposed the comparison of the whole con- centration-response curve of the mixture observed with that predicted by the additive reference model to analyze the toxicity interaction such as synergism or antagonism taken place in a mixture, and designed a computer program named as the as

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

    Science.gov (United States)

    Hervás, C; Toledo, R; Silva, M

    2001-01-01

    The suitability of pruned computational neural networks (CNNs) for resolving nonlinear multicomponent systems involving synergistic effects by use of oscillating chemical reaction-based methods implemented using the analyte pulse perturbation technique is demonstrated. The CNN input data used for this purpose are estimates provided by the Levenberg-Marquardt method in the form of a three-parameter Gaussian curve associated with the singular profile obtained when the oscillating system is perturbed by an analyte mixture. The performance of the proposed method was assessed by applying it to the resolution of mixtures of pyrogallol and gallic acid based on their perturbating effect on a classical oscillating chemical system, viz. the Belousov-Zhabotinskyi reaction. A straightforward network topology (3:3:2, with 18 connections after pruning) allowed the resolution of mixtures of the two analytes in concentration ratios from 1:7 to 6:2 with a standard error of prediction for the testing set of 4.01 and 8.98% for pyrogallol and gallic acid, respectively. The reduced dimensions of the selected CNN architecture allowed a mathematical transformation of the input vector into the output one that can be easily implemented via software. Finally, the suitability of response surface analysis as an alternative to CNNs was also tested. The results were poor (relative errors were high), which confirms that properly selected pruned CNNs are effective tools for solving the analytical problem addressed in this work. PMID:11500128

  14. Modeling of the gas-phase chemistry in C-H-O gas mixtures for diamond chemical vapor deposition

    Science.gov (United States)

    Petherbridge, James R.; May, Paul W.; Ashfold, Michael N. R.

    2001-05-01

    The boundaries of the diamond deposition region in the C-H-O (Bachmann) atomic phase composition diagram have been reproduced successfully for 38 different C, H, and O containing gas mixtures using the CHEMKIN computer package, together with just two criteria—a minimum mole fraction of methyl radicals [CH3] and a limiting value of the [H]/[C2H2] ratio. The diamond growth/no-growth boundary coincides with the line along which the input mole fractions of C and O are equal. For every gas mixture studied, no-growth regions are found to coincide with a negligible (<10-10) mole fraction of CH3 radicals, while for gas mixtures lying within the diamond growth region the CH3 mole fraction is ˜10-7. Each no-growth→diamond growth boundary is seen to be accompanied by a 2-3 order of magnitude step in CH3 mole fraction. The boundary between diamond and nondiamond growth is less clearly defined, but can be reproduced by assuming a critical, temperature dependent [H]/[C2H2] ratio (0.2, in the case that Tgas=2000 K) that reflects the crucial role of H atoms in the etching of nondiamond phases. The analysis allows prediction of the composition process window for good quality diamond growth for all stable input gas mixtures considered in this study.

  15. Application of the cubic-plus-association equation of state to mixtures with polar chemicals and high pressures

    DEFF Research Database (Denmark)

    Folas, Georgios; Kontogeorgis, Georgios; Michelsen, Michael Locht; Stenby, Erling Halfdan

    2006-01-01

    The cubic-plus-association (CPA) equation of state has been previously applied to vapor-liquid, liquid-liquid, and solid-liquid equilibria of mixtures containing associating compounds (water, alcohols, glycols, acids, amines). Although some high-pressure applications have been presented, emphasis...

  16. Probabilistic human health risk assessment of degradation-related chemical mixtures in heterogeneous aquifers: Risk statistics, hot spots, and preferential channels

    Science.gov (United States)

    Henri, Christopher V.; Fernández-Garcia, Daniel; Barros, Felipe P. J.

    2015-06-01

    The increasing presence of toxic chemicals released in the subsurface has led to a rapid growth of social concerns and the need to develop and employ models that can predict the impact of groundwater contamination on human health risk under uncertainty. Monitored natural attenuation is a common remediation action in many contamination cases. However, natural attenuation can lead to the production of daughter species of distinct toxicity that may pose challenges in pollution management strategies. The actual threat that these contaminants pose to human health depends on the interplay between the complex structure of the geological media and the toxicity of each pollutant byproduct. This work addresses human health risk for chemical mixtures resulting from the sequential degradation of a contaminant (such as a chlorinated solvent) under uncertainty through high-resolution three-dimensional numerical simulations. We systematically investigate the interaction between aquifer heterogeneity, flow connectivity, contaminant injection model, and chemical toxicity in the probabilistic characterization of health risk. We illustrate how chemical-specific travel times control the regime of the expected risk and its corresponding uncertainties. Results indicate conditions where preferential flow paths can favor the reduction of the overall risk of the chemical mixture. The overall human risk response to aquifer connectivity is shown to be nontrivial for multispecies transport. This nontriviality is a result of the interaction between aquifer heterogeneity and chemical toxicity. To quantify the joint effect of connectivity and toxicity in health risk, we propose a toxicity-based Damköhler number. Furthermore, we provide a statistical characterization in terms of low-order moments and the probability density function of the individual and total risks.

  17. An in vivo animal study assessing long-term changes in hypothalamic cytokines following perinatal exposure to a chemical mixture based on Arctic maternal body burden

    Directory of Open Access Journals (Sweden)

    Li Nanqin

    2011-07-01

    Full Text Available Abstract Background The geographic distribution of environmental toxins is generally not uniform, with certain northern regions showing a particularly high concentration of pesticides, heavy metals and persistent organic pollutants. For instance, Northern Canadians are exposed to high levels of persistent organic pollutants like polychlorinated biphenyls (PCB, organochlorine pesticides (OCs and methylmercury (MeHg, primarily through country foods. Previous studies have reported associations between neuronal pathology and exposure to such toxins. The present investigation assessed whether perinatal exposure (gestation and lactation of rats to a chemical mixture (27 constituents comprised of PCBs, OCs and MeHg based on Arctic maternal exposure profiles at concentrations near human exposure levels, would affect brain levels of several inflammatory cytokines Methods Rats were dosed during gestation and lactation and cytokine levels were measured in the brains of offspring at five months of age. Hypothalamic cytokine protein levels were measured with a suspension-based array system and differences were determined using ANOVA and post hoc statistical tests. Results The early life PCB treatment alone significantly elevated hypothalamic interleukin-6 (IL-6 levels in rats at five months of age to a degree comparable to that of the entire chemical mixture. Similarly, the full mixture (and to a lesser degree PCBs alone elevated levels of the pro-inflammatory cytokine, IL-1b, as well as the anti-inflammatory cytokine, IL-10. The full mixture of chemicals also moderately increased (in an additive fashion hypothalamic levels of the pro-inflammatory cytokines, IL-12 and tumor necrosis factor (TNF-α. Challenge with bacterial endotoxin at adulthood generally increased hypothalamic levels to such a degree that differences between the perinatally treated chemical groups were no longer detectable. Conclusions These data suggest that exposure at critical

  18. Testing the effects of opacity and the chemical mixture on the excitation of pulsations in B stars of the Magellanic Clouds

    Science.gov (United States)

    Salmon, S.; Montalbán, J.; Morel, T.; Miglio, A.; Dupret, M.-A.; Noels, A.

    2012-06-01

    The B-type pulsators known as β Cephei and slowly pulsating B (SPB) stars present pulsations driven by the κ mechanism, which operates thanks to an opacity bump due to the iron-group elements. In low-metallicity environments such as the Magellanic Clouds, β Cep and SPB pulsations are not expected. Nevertheless, recent observations show evidence for the presence of B-type pulsator candidates in both galaxies. We seek an explanation for the excitation of β Cep and SPB modes in those galaxies by examining basic input physics in stellar modelling: (i) the specific metal mixture of B-type stars in the Magellanic Clouds and (ii) the role of a potential underestimation of stellar opacities. We first derive the present-day chemical mixtures of B-type stars in the Magellanic Clouds. Then, we compute stellar models for that metal mixture and perform a non-adiabatic analysis of these models. In the second approach, we simulate parametric enhancements of stellar opacities due to different iron-group elements. We then study their effects in models of B stars and their stability. We find that adopting a representative chemical mixture of B stars in the Small Magellanic Cloud cannot explain the presence of B-type pulsators there. An increase of the opacity in the region of the iron-group bump could drive B-type pulsations, but only if this increase occurs at the temperature corresponding to the maximum contribution of Ni to this opacity bump. We recommend an accurate computation of the Ni opacity to understand B-type pulsators in the Small Magellanic Cloud, as well as the frequency domain observed in some Galactic hybrid β Cep-SPB stars.

  19. Probing structural patterns of ion association and solvation in mixtures of imidazolium ionic liquids with acetonitrile by means of relative (1)H and (13)C NMR chemical shifts.

    Science.gov (United States)

    Marekha, Bogdan A; Kalugin, Oleg N; Bria, Marc; Idrissi, Abdenacer

    2015-09-21

    Mixtures of ionic liquids (ILs) with polar aprotic solvents in different combinations and under different conditions (concentration, temperature etc.) are used widely in electrochemistry. However, little is known about the key intermolecular interactions in such mixtures depending on the nature of the constituents and mixture composition. In order to systematically address the intermolecular interactions, the chemical shift variation of (1)H and (13)C nuclei has been followed in mixtures of imidazolium ILs 1-n-butyl-3-methylimidazolium tetrafluoroborate (BmimBF4), 1-n-butyl-3-methylimidazolium hexafluorophosphate (BmimPF6), 1-n-butyl-3-methylimidazolium trifluoromethanesulfonate (BmimTfO) and 1-n-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (BmimTFSI) with molecular solvent acetonitrile (AN) over the entire composition range at 300 K. The concept of relative chemical shift variation is proposed to assess the observed effects on a unified and unbiased scale. We have found that hydrogen bonds between the imidazolium ring hydrogen atoms and electronegative atoms of anions are stronger in BmimBF4 and BmimTfO ILs than those in BmimTFSI and BmimPF6. Hydrogen atom at position 2 of the imidazolium ring is substantially more sensitive to interionic hydrogen bonding than those at positions 4-5 in the case of BmimTfO and BmimTFSI ILs. These hydrogen bonds are disrupted upon dilution in AN due to ion dissociation which is more pronounced at high dilutions. Specific solvation interactions between AN molecules and IL cations are poorly manifested. PMID:26278514

  20. The Effect of Molecular Conformation on the Accuracy of Theoretical (1)H and (13)C Chemical Shifts Calculated by Ab Initio Methods for Metabolic Mixture Analysis.

    Science.gov (United States)

    Chikayama, Eisuke; Shimbo, Yudai; Komatsu, Keiko; Kikuchi, Jun

    2016-04-14

    NMR spectroscopy is a powerful method for analyzing metabolic mixtures. The information obtained from an NMR spectrum is in the form of physical parameters, such as chemical shifts, and construction of databases for many metabolites will be useful for data interpretation. To increase the accuracy of theoretical chemical shifts for development of a database for a variety of metabolites, the effects of sets of conformations (structural ensembles) and the levels of theory on computations of theoretical chemical shifts were systematically investigated for a set of 29 small molecules in the present study. For each of the 29 compounds, 101 structures were generated by classical molecular dynamics at 298.15 K, and then theoretical chemical shifts for 164 (1)H and 123 (13)C atoms were calculated by ab initio quantum chemical methods. Six levels of theory were used by pairing Hartree-Fock, B3LYP (density functional theory), or second order Møller-Plesset perturbation with 6-31G or aug-cc-pVDZ basis set. The six average fluctuations in the (1)H chemical shift were ±0.63, ± 0.59, ± 0.70, ± 0.62, ± 0.75, and ±0.66 ppm for the structural ensembles, and the six average errors were ±0.34, ± 0.27, ± 0.32, ± 0.25, ± 0.32, and ±0.25 ppm. The results showed that chemical shift fluctuations with changes in the conformation because of molecular motion were larger than the differences between computed and experimental chemical shifts for all six levels of theory. In conclusion, selection of an appropriate structural ensemble should be performed before theoretical chemical shift calculations for development of an accurate database for a variety of metabolites. PMID:26963288

  1. Development of a research strategy for integrated technology-based toxicological and chemical evaluation of complex mixtures of drinking water disinfection byproducts.

    Science.gov (United States)

    Simmons, Jane Ellen; Richardson, Susan D; Speth, Thomas F; Miltner, Richard J; Rice, Glenn; Schenck, Kathleen M; Hunter, E Sidney; Teuschler, Linda K

    2002-12-01

    Chemical disinfection of water is a major public health triumph of the 20th century. Dramatic decreases in both morbidity and mortality of waterborne diseases are a direct result of water disinfection. With these important public health benefits comes low-level, chronic exposure to a very large number of disinfection byproducts (DBPs), chemicals formed through reaction of the chemical disinfectant with naturally occurring inorganic and organic material in the source water. This article provides an overview of joint research planning by scientists residing within the various organizations of the U.S. Environmental Protection Agency Office of Research and Development. The purpose is to address concerns related to potential health effects from exposure to DBPs that cannot be addressed directly from toxicological studies of individual DBPs or simple DBP mixtures. Two factors motivate the need for such an investigation of complex mixtures of DBPs: a) a significant amount of the material that makes up the total organic halide and total organic carbon portions of the DBPs has not been identified; and b) epidemiologic data, although not conclusive, are suggestive of potential developmental, reproductive, or carcinogenic health effects in humans exposed to DBPs. The plan is being developed and the experiments necessary to determine the feasibility of its implementation are being conducted by scientists from the National Health and Environmental Effects Research Laboratory, the National Risk Management Research Laboratory, the National Exposure Research Laboratory, and the National Center for Environmental Assessment. PMID:12634133

  2. Differentiation of Chemical Components in a Binary Solvent Vapor Mixture Using Carbon/Polymer Composite-Based Chemiresistors

    Energy Technology Data Exchange (ETDEWEB)

    Patel, Sanjay V.; Jenkins, Mark W.; Hughes, Robert C.; Yelton, W. Graham; Ricco, Antonio J.

    1999-07-19

    We demonstrate a ''universal solvent sensor'' constructed from a small array of carbon/polymer composite chemiresistors that respond to solvents spanning a wide range of Hildebrand volubility parameters. Conductive carbon particles provide electrical continuity in these composite films. When the polymer matrix absorbs solvent vapors, the composite film swells, the average separation between carbon particles increases, and an increase in film resistance results, as some of the conduction pathways are broken. The adverse effects of contact resistance at high solvent concentrations are reported. Solvent vapors including isooctane, ethanol, dlisopropyhnethylphosphonate (DIMP), and water are correctly identified (''classified'') using three chemiresistors, their composite coatings chosen to span the full range of volubility parameters. With the same three sensors, binary mixtures of solvent vapor and water vapor are correctly classified, following classification, two sensors suffice to determine the concentrations of both vapor components. Polyethylene vinylacetate and polyvinyl alcohol (PVA) are two such polymers that are used to classify binary mixtures of DIMP with water vapor; the PVA/carbon-particle-composite films are sensitive to less than 0.25{degree}A relative humidity. The Sandia-developed VERI (Visual-Empirical Region of Influence) technique is used as a method of pattern recognition to classify the solvents and mixtures and to distinguish them from water vapor. In many cases, the response of a given composite sensing film to a binary mixture deviates significantly from the sum of the responses to the isolated vapor components at the same concentrations. While these nonlinearities pose significant difficulty for (primarily) linear methods such as principal components analysis, VERI handles both linear and nonlinear data with equal ease. In the present study the maximum speciation accuracy is achieved by an array

  3. Chemical-physical characterization of a binary mixture made of a photosensitive azobenzene derivative and a smectogen

    Czech Academy of Sciences Publication Activity Database

    Borello, E.; Cifelli, M.; Duce, C.; Galli, G.; Tine, M.R.; Hamplová, Věra; Ambrozic, G.; Domenici, V.

    2015-01-01

    Roč. 614, č. 1 (2015), s. 54-61. ISSN 1542-1406 R&D Projects: GA ČR GA13-14133S; GA MŠk(CZ) 7AMB14PL035 Grant ostatní: AVČR(CZ) M100101204; AVČR(CZ) M100101211 Institutional support: RVO:68378271 Keywords : liquid crystalline mixture * nematic * smectic A * photosensitive molecules * DSC * 2HNMR Subject RIV: CC - Organic Chemistry Impact factor: 0.493, year: 2014

  4. The Effect of Pressure on the Dissociation of H2/CH4 Gas Mixture during Diamond Films Growth via Chemical Vapor Deposition

    Institute of Scientific and Technical Information of China (English)

    赵庆勋; 辛红丽; 韩佳宁; 文钦若; 杨景发

    2002-01-01

    Monte Carlo simulations are adopted to study the electron motion in the mixture of H2 and CH4 during diamond synthesis via Glow Plasma-assisted Chemical Vapor Deposition (GPCVD). The non-uniform electric field is used and the avalanche of electrons is taken into account in this simulation. The average energy distribution of electrons and the space distribution of effective species such as CH3, CH3+, CH+ and H at various gas pressures are given in this paper,and optimum experimental conditions are inferred from these results,

  5. Testing the effects of opacity and the chemical mixture on the excitation of pulsations in B stars of the Magellanic Clouds

    CERN Document Server

    Salmon, S; Morel, T; Miglio, A; Dupret, M-A; Noels, A

    2012-01-01

    The B-type pulsators known as \\beta Cephei and Slowly Pulsating B (SPB) stars present pulsations driven by the \\kappa mechanism, which operates thanks to an opacity bump due to the iron group elements. In low-metallicity environments such as the Magellanic Clouds, \\beta Cep and SPB pulsations are not expected. Nevertheless, recent observations show evidence for the presence of B-type pulsator candidates in both galaxies. We seek an explanation for the excitation of \\beta Cep and SPB modes in those galaxies by examining basic input physics in stellar modelling: i) the specific metal mixture of B-type stars in the Magellanic Clouds; ii) the role of a potential underestimation of stellar opacities. We first derive the present-day chemical mixtures of B-type stars in the Magellanic Clouds. Then, we compute stellar models for that metal mixture and perform a non-adiabatic analysis of these models. In a second approach, we simulate parametric enhancements of stellar opacities due to different iron group elements. W...

  6. Time-dependent hormesis of chemical mixtures: A case study on sulfa antibiotics and a quorum-sensing inhibitor of Vibrio fischeri.

    Science.gov (United States)

    You, Ruirong; Sun, Haoyu; Yu, Yan; Lin, Zhifen; Qin, Mengnan; Liu, Ying

    2016-01-01

    Sulfa antibiotics (SAs) and quorum-sensing inhibitor (QSI) may pose potential ecological risks because mixed using of them has been proposed to inhibit bacteria from generating antibiotic resistance. This study investigated the time-dependent hormesis of single and binary mixtures of QSI and SAs of Vibrio fischeri (V. fischeri) for 0-24 h. Although the low-dose SAs stimulated the expression of LuxR protein, the high-dose SAs could inhibit bacteria growth by competitively binding to dihydropteroate synthase. Moreover, AinR protein was bound to Benzofuran-3(2H)-one (B3O) with low concentration, thus the N-octanoyl homoserine lactone signal molecules (C8) has chance to bind to LuxR protein to promote light emission. The hormesis effect induced by the mixtures could be deduced that SAs promoted the expression of LuxR protein and B3O increases the chance of C8 binding to LuxR. Our findings facilitate new insight into the mechanistic study of hormesis and ecological risks of the chemical mixtures. PMID:26645135

  7. XV International conference on chemical thermodynamics in Russia. RCCT-2005. Summary of reports. Volume II

    International Nuclear Information System (INIS)

    Proceedings of the XV International conference on chemical thermodynamics are performed. The release covers wide frame on physical chemistry and chemical thermodynamics, and present-day conception on properties as individual substances, so their mixtures on phase and chemical equilibriums, surface effects in different systems is demonstrated. Solutions and melts, complex fluid systems (polymer solutions, liquid crystals, micellar solutions), new materials are part of concerned problems. Theoretical and experimental methods of chemical thermodynamics, automated experimental databases are among discussed problems

  8. XV International conference on chemical thermodynamics in Russia. RCCT-2005. Summary of reports. Volume I

    International Nuclear Information System (INIS)

    Proceedings of the XV International conference on chemical thermodynamics are performed. The release covers wide frame on physical chemistry and chemical thermodynamics, and present-day conception on properties as individual substances, so their mixtures on phase and chemical equilibriums, surface effects in different systems is demonstrated. Solutions and melts, complex fluid systems (polymer solutions, liquid crystals, micellar solutions), new materials are part of concerned problems. Theoretical and experimental methods of chemical thermodynamics, automated experimental databases are among discussed problems

  9. Chemical imaging techniques for the analysis of complex mixtures: New application to the characterization of ritual matters on African wooden statuettes

    International Nuclear Information System (INIS)

    Chemical imaging techniques, based on the combination of microscopy and spectroscopy, are well suited to study both the composition and the spatial organization of heterogeneous complex mixtures of organic and mineral matter. Time-of-flight secondary ion mass spectrometry (ToF-SIMS), followed by scanning electron microscopy with energy dispersive X-ray analysis (SEM-EDX) and Fourier transform infrared microscopy (FTIR microscopy) have been applied to non-destructive analysis of micro-samplings of ritual matters deposited on the surface of African wooden statuettes. With a very careful preparation, using ultramicrotomy on embedded samples, it was possible to perform successively all the measurements on a single fragment. Comparison and superposition of the different chemical images, obtained on a sample from a significant actual artefact, have allowed us to identify minerals (clays, quartz and calcium carbonate), proteins, starch, urate salts and lipids and to map their spatial distribution

  10. Physico-chemical properties of binary mixtures of aliphatic and aromatic solvents at 313 K on acoustical data

    Science.gov (United States)

    Dahire, S. L.; Morey, Y. C.; Agrawal, P. S.

    2015-12-01

    Density (ρ), viscosity (η), and ultrasonic velocity ( U) of binary mixtures of aliphatic solvents like dimethylformamide (DMF) and dimethylsulfoxide (DMSO) with aromatic solvents viz. chlorobenzene (CB), bromobenzene (BB), and nitrobenzene (NB) have been determined at 313 K. These parameters were used to calculate the adiabatic compressibility (β), intermolecular free length ( L f), molar volume ( V m), and acoustic impedance ( Z). From the experimental data excess molar volume ( V m E ), excess intermolecular free length ( L f E )), excess adiabatic compressibility (βE), and excess acoustic impedance ( Z E) have been computed. The excess values were correlated using Redlich-Kister polynomial equation to obtain their coefficients and standard deviations (σ).

  11. Atomic-scale modeling of chemical vapor deposition processes from new complicated gas-phase mixtures for micro- and nanoelectronic applications

    Science.gov (United States)

    Makhviladze, T. M.; Sarychev, M. E.

    2009-01-01

    Low-pressure chemical vapor deposition (CVD) is one of the most important processes for obtaining thin films widely used in semiconductor and in IC technology. Because of the baffling complexity of deposition process the usually-used approaches in CVD modeling include a great number of empiric non-calculated parameters, and this drawback becomes a grave disadvantage if one needs to model the process with new reagents and materials which were not used before. So we place primary emphasis upon the development of non-empirical deposition models that rely on phenomenological theories and experimental data only to a minimal extent. We are presenting the atomistic-scale models and software package throughout the entire deposition process that are based mainly on the first principles and ab initio methods. The main modeling stages are studied and discussed in detail, namely: atomistic modeling of gas-phase and surface reactions, determination of the basic chemical and physical mechanisms for the considered gas mixtures, calculations of the reactions rates for elementary reactions and acts, Monte Carlo and/or molecular dynamics simulation of the thin film growth, and modeling of macrokinetic processes in realistic deposition flow-reactor chamber. The modeling results for thin films deposition from actual gas mixtures are given. The physical properties of films as well as their stoichiometric composition and structure in dependence of process conditions are discussed.

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

    International Nuclear Information System (INIS)

    Highlights: • State-to-state approach for coupled vibrational relaxation and chemical reactions. • Self-consistent model for rates of non-equilibrium reactions and energy transitions. • In viscous flows mass action law is violated. • Cross coupling between reaction rates and non-equilibrium pressure in viscous flow. • Results allow implementing the state-to-state approach for viscous flow simulations. - Abstract: Viscous gas flows with vibrational relaxation and chemical reactions in the state-to-state approach are analyzed. A modified Chapman–Enskog method is used for the determination of chemical reaction and vibrational transition rates and non-equilibrium pressure. Constitutive equations depend on the thermodynamic forces: velocity divergence and chemical reaction/transition affinity. As an application, N2 flow with vibrational relaxation across a shock wave is investigated. Two distinct processes occur behind the shock: for small values of the distance the affinity is large and vibrational relaxation is in its initial stage; for large distances the affinity is small and the chemical reaction is in its final stage. The affinity contributes more to the transition rate than the velocity divergence and the effect of these two contributions are more important for small distances from the shock front. For the non-equilibrium pressure, the term associated with the bulk viscosity increases by a small amount the hydrostatic pressure

  13. High sensitivity stand-off detection and quantification of chemical mixtures using an active coherent laser spectrometer (ACLaS)

    Science.gov (United States)

    MacLeod, Neil A.; Weidmann, Damien

    2016-05-01

    High sensitivity detection, identification and quantification of chemicals in a stand-off configuration is a highly sought after capability across the security and defense sector. Specific applications include assessing the presence of explosive related materials, poisonous or toxic chemical agents, and narcotics. Real world field deployment of an operational stand-off system is challenging due to stringent requirements: high detection sensitivity, stand-off ranges from centimeters to hundreds of meters, eye-safe invisible light, near real-time response and a wide chemical versatility encompassing both vapor and condensed phase chemicals. Additionally, field deployment requires a compact, rugged, power efficient, and cost-effective design. To address these demanding requirements, we have developed the concept of Active Coherent Laser Spectrometer (ACLaS), which can be also described as a middle infrared hyperspectral coherent lidar. Combined with robust spectral unmixing algorithms, inherited from retrievals of information from high-resolution spectral data generated by satellitebased spectrometers, ACLaS has been demonstrated to fulfil the above-mentioned needs. ACLaS prototypes have been so far developed using quantum cascade lasers (QCL) and interband cascade lasers (ICL) to exploit the fast frequency tuning capability of these solid state sources. Using distributed feedback (DFB) QCL, demonstration and performance analysis were carried out on narrow-band absorbing chemicals (N2O, H2O, H2O2, CH4, C2H2 and C2H6) at stand-off distances up to 50 m using realistic non cooperative targets such as wood, painted metal, and bricks. Using more widely tunable external cavity QCL, ACLaS has also been demonstrated on broadband absorbing chemicals (dichloroethane, HFC134a, ethylene glycol dinitrate and 4-nitroacetanilide solid) and on complex samples mixing narrow-band and broadband absorbers together in a realistic atmospheric background.

  14. The use of superoxide mixtures as air-revitalization chemicals in hyperbaric, self-contained, closed-circuit breathing apparatus

    Science.gov (United States)

    Wood, P. C.; Wydeven, T.

    1985-01-01

    In portable breathing apparatus applications at 1 atm, potassium superoxide (KO2) has exhibited low-utilization efficiency of the available oxygen (O2) and diminished carbon dioxide-(CO2) scrubbing capacity caused by the formation of a fused, hydrated-hydroxide/carbonate product coating on the superoxide granules. In earlier work, it was discovered that granules fabricated from an intimate mixture of KO2 and calcium superoxide, Ca(O2)2, did not exhibit formation of a fused product coating and the utilization efficiency with respect to both O2 release and CO2 absorption was superior to KO2 granules when both types of granules were reacted with humidified CO2 under identified conditions. In the work described here, single pellets of KO2, KO2/Ca(O2), mixtures and commercially available KO2 tables and granules were reacted with a flow of humidified CO2 in helium at 1- and 10-atm total pressure and at an initial temperature of 40 C. In the 1-atm flow tests, the reaction rates and utilization efficiency of the KO2/Ca(O2)2 pellets were markedly superior to the KO2 pellets, tablets, and granules when the samples were reacted under identical conditions. However, at 10 atm, the rates of O2 release and CO2 absorption, as well as the utilization efficiencies of all the superoxide samples, were one-third to one-eighth of the values observed at 1 atm. The decrease in reaction performance at 10 atm compared to that at 1 atm has been attributed principally to the lower bulk diffusivity of the CO2 and H2O reactants in helium at the higher pressure and secondarily to the moderation of the reaction temperature caused by the higher heat capacity of the 10-atm helium.

  15. Proceedings of the 3. International conference on waste management in the chemical and petrochemical industries. Volume 1 and 2.

    Energy Technology Data Exchange (ETDEWEB)

    Lima, Francisco F.; Pereira Filho, Francisco A.; Almeida, Sergio A.S. [eds.

    1993-12-31

    To produce without pollution is today a mandate for the preservation of our society. To produce cleaner means to conserve energy and natural resources, to reduce the use of toxic substances, to invest in the evolution of products and production processes towards a minimum of residues. The Third International Conference on Waste Minimization in the Chemical and Petrochemical Industries addresses these challenging questions regarding waste minimization

  16. Effect of glow DBD modulation on gas and thin film chemical composition: case of Ar/SiH4/NH3 mixture

    International Nuclear Information System (INIS)

    In recent years, atmospheric pressure plasma-enhanced chemical vapour deposition has been identified as a convenient way to deposit good quality thin films. With this type of process, where the gas mixture is injected on one side of the electrodes, the chemical composition of the gas evolves with the gas residence time in the plasma. The consequence is a possible gradient in the chemical composition over the thickness of in-line coatings. The present work shows that the modulation of the plasma with a square signal significantly reduces this gradient while the drawback of low growth rate is avoided by increasing the discharge power. This study deals with plane/plane glow dielectric barrier discharges (DBDs) in an Ar/NH3/SiH4 gas mixture to make thin films. The 50 kHz discharge power of the glow DBD was varied by increasing voltage and modulating excitation. The impact on (i) the plasma development was observed through emission spectroscopy and (ii) the thin film coating through Fourier transform infrared measurements. It is shown that the modulation significantly decreases the time and the energy needed to achieve stable chemistry, enhances secondary chemistry and limits disturbance induced by impurities because of a slower decrease of SiH4 concentration and thus a higher ratio of SiH4/impurities, all very important points for in-line AP-PECVD development. When the growth rate is limited by diffusion, coating growth continues when the discharge is off, so long as there is a precursor gradient between the surface and the gas bulk. A higher discharge power steepens this gradient, which enhances diffusion from the bulk and thus growth rate. (paper)

  17. NUMERICAL ALGORITHMS AT NON-ZERO CHEMICAL POTENTIAL. PROCEEDINGS OF RIKEN BNL RESEARCH CENTER WORKSHOP, VOLUME 19

    Energy Technology Data Exchange (ETDEWEB)

    BLUM,T.

    1999-09-14

    The RIKEN BNL Research Center hosted its 19th workshop April 27th through May 1, 1999. The topic was Numerical Algorithms at Non-Zero Chemical Potential. QCD at a non-zero chemical potential (non-zero density) poses a long-standing unsolved challenge for lattice gauge theory. Indeed, it is the primary unresolved issue in the fundamental formulation of lattice gauge theory. The chemical potential renders conventional lattice actions complex, practically excluding the usual Monte Carlo techniques which rely on a positive definite measure for the partition function. This ''sign'' problem appears in a wide range of physical systems, ranging from strongly coupled electronic systems to QCD. The lack of a viable numerical technique at non-zero density is particularly acute since new exotic ''color superconducting'' phases of quark matter have recently been predicted in model calculations. A first principles confirmation of the phase diagram is desirable since experimental verification is not expected soon. At the workshop several proposals for new algorithms were made: cluster algorithms, direct simulation of Grassman variables, and a bosonization of the fermion determinant. All generated considerable discussion and seem worthy of continued investigation. Several interesting results using conventional algorithms were also presented: condensates in four fermion models, SU(2) gauge theory in fundamental and adjoint representations, and lessons learned from strong; coupling, non-zero temperature and heavy quarks applied to non-zero density simulations.

  18. Topical Meeting on Laser Applications to Chemical Analysis III, Salt Lake City, UT, Jan. 27-31, 1992, Proceedings

    Science.gov (United States)

    Miziolek, Andrzej W.; Long, S. R.; Crosley, David R.

    1993-02-01

    Various papers on lasers, photonics, and environmental optics are presented. Individual topics addressed include: tunable diode laser ratio measurements of atmospheric constituents employing dual fitting analysis and jump scanning, ultrasensitive spectral trace detection of individual molecular components in an atmospheric binary mixture, applications of a tunable CO2 sideband lasers for high-resolution spectroscopic measurements of atmospheric gases, molecular analysis by ionization of laser-desorbed neutral species, spatially resolved multispecies and temperature analysis in hydrogen flames, intense backward Raman lasers in CH4 and H2, time-resolved emission studies of ArF-laser-produced microplasmas. Also discussed are: measurements of the refractive index of PbEuTe in the 3-10 micron region of the infrared, high-efficiency and compact blue source: intracavity frequency tripling by using LBO and BBO without the influence of birefringence, radiation and collisional energy transfer among the A 2Pi(i) and X 2Sigma(+) states of CN, wager-vapor absorption line measurements in the 940-nm band using a Raman-shifted dye laser, Gaussian-Schell model source in 1D first-order systems with loss or gain. (For individual items see A93-28552 to A93-28566)

  19. Growth and chemical composition of chicory and performance of lambs grazing chicory relative to grass–clover mixtures

    OpenAIRE

    Kidane, Alemayehu; Sørheim, Kristin; Eik, Lars Olav; Steinshamn, Håvard

    2014-01-01

    We report results from trials on chicory growth (experiment 1) and lamb growth on chicory (experiment 2). In experiment 1, we assessed yield and chemical composition on swards established under organic conditions as perennial ryegrass/red clover, perennial ryegrass/chicory, chicory/red clover (CHRC), pure perennial ryegrass (RG-alone) and pure chicory (CHalone) over two years. Chicory/red clover and CH-alone showed improved crude protein, Ca, Mg, P, Cu and net energy contents comp...

  20. Supersymmetry: proceedings

    International Nuclear Information System (INIS)

    Some lectures in these proceedings examine the theoretical basis for supersymmetry, recent developments in theories with compact dimensions, and experimental searches for supersymmetric signatures. Technologies are explored for obtaining very high energy electron-positron colliding beams. Separate abstracts were prepared for 35 papers in these conference proceedings

  1. Supersymmetry: proceedings

    Energy Technology Data Exchange (ETDEWEB)

    Brennan, E.C. (ed.)

    1985-07-01

    Some lectures in these proceedings examine the theoretical basis for supersymmetry, recent developments in theories with compact dimensions, and experimental searches for supersymmetric signatures. Technologies are explored for obtaining very high energy electron-positron colliding beams. Separate abstracts were prepared for 35 papers in these conference proceedings. (LEW)

  2. Spectral properties of mixtures of montmorillonite and dark grains - Implications for remote sensing minerals containing chemically and physically adsorbed water

    Science.gov (United States)

    Clark, R. N.

    1983-01-01

    The spectral properties from 0.4 to 3 microns of montmorillonite plus dark carbon grains (called opaques) of various sizes are studied as a function of the weight fraction of opaques present. The reflectance level and band depths of the 1.4-, 1.9-, 2.2-, and 2.8-micron water and/or OH absorption features are analyzed using derived empirical relationships and scattering theory. It is found that the absorption band depths and reflectance level are a very nonlinear function of the weight fraction of opaques present but can be predicted in many cases by simple scattering theory. The 2.8-micron bound water fundamental band is the most difficult absorption feature to suppress. The overtone absorptions are suppressed a greater amount than the fundamental but are still apparent even when 10-20 wt pct opaques are present. The relationships observed and the simple scattering theory presented show that quantitative compositional remote sensing studies are feasible for surfaces containing complex mineral mixtures.

  3. Spectroscopic study of chemical composition of high-frequency glow-discharge in halogen-containing gas mixtures

    International Nuclear Information System (INIS)

    This paper presents a spectroscopic study of high-frequency (HF) gas discharge in mixtures of fluorine- and chlorine-containing gases: trichlorotrifluoroethane (C2F3Cl3), sulfur hexafluoride (SF6), and tetrafluoromethane (CF4). The optical emission spectrum of the plasma was recorded in the range of 200-800 nm by the photoelectric method, using an MDR-23 monochromator, FEU-79 and FEU-39A radiation dectectors. A small amount of argon was added to the plasma-forming gas to determine the concentration of atoms and radicals and change in the plasma parameters when the discharge burning regimes are changed. The experiments showed that the most probable molecule emitting the 280-335-nm band with a maximum at lambdamax = 306 nm is si /SUB x/ S /SUB y/ Fz. It can be formed as a result of the interaction of sulfur-fluorine containing radicals with the silicon surface, or in the bulk of the material, due to the reaction of SiF /SUB m/ and SF /SUB n/ radicals

  4. Uncertainty in Mixtures and Cumulative Risk Assessment

    Science.gov (United States)

    Humans and environmental species are rarely exposed to single chemicals. These chemicals typically affect multiple tissues through multiple modes of action, which may depend on the dose. Mixtures risk assessment may employ dose response information from the mixture of interest,...

  5. An approximate method for solving the problem of the establishment of chemical equilibrium in the products of explosion of gas mixture

    Science.gov (United States)

    Shargatov, V. A.; Gubin, S. A.; Okunev, D. Yu

    2015-11-01

    Based on the assumption of the existence of the partial chemical equilibrium in the detonation products, an approximate method for calculating composition of the detonation products is developed. The method uses the assumption of the existence of extremum of Helmholtz free energy for a given density, temperature, and molecular weight of the detonation products mixture. Without significant loss of accuracy to the solution of stiff differential equations, detailed kinetic mechanism can be replaced by one differential equation and a system of algebraic equations. This method is always consistent with the detailed mechanism and can be used separately or in conjunction with the decision of a stiff system, replacing it when bimolecular reactions are near equilibrium.

  6. Mixtures and interactions

    NARCIS (Netherlands)

    Groten, J.P.

    2000-01-01

    Drinking water can be considered as a complex mixture that consists of tens, hundreds or thousands of chemicals of which the composition is qualitatively and quantitatively not fully known. From a public health point of view it is most relevant to answer the question of whether chemicals in drinking

  7. Chemical kinetic study of the oxidation of a biodiesel-bioethanol surrogate fuel: methyl octanoate-ethanol mixtures.

    Science.gov (United States)

    Togbé, C; May-Carle, J-B; Dayma, G; Dagaut, P

    2010-03-25

    There is a growing interest for using bioethanol-biodiesel fuel blends in diesel engines but no kinetic data and model for their combustion were available. Therefore, the kinetics of oxidation of a biodiesel-bioethanol surrogate fuel (methyl octanoate-ethanol) was studied experimentally in a jet-stirred reactor at 10 atm and constant residence time, over the temperature range 560-1160 K, and for several equivalence ratios (0.5-2). Concentration profiles of reactants, stable intermediates, and final products were obtained by probe sampling followed by online FTIR, and off-line gas chromatography analyses. The oxidation of this fuel in these conditions was modeled using a detailed chemical kinetic reaction mechanism consisting of 4592 reversible reactions and 1087 species. The proposed kinetic reaction mechanism yielded a good representation of the kinetics of oxidation of this biodiesel-bioethanol surrogate under the JSR conditions. The modeling was used to delineate the reactions triggering the low-temperature oxidation of ethanol important for diesel engine applications. PMID:20235606

  8. On Modeling the Response of Synovial Fluid: Unsteady Flow of a Shear-Thinning, Chemically-Reacting Fluid Mixture

    CERN Document Server

    Bridges, Craig; Rajagopal, K R

    2010-01-01

    We study the flow of a shear-thinning, chemically-reacting fluid that could be used to model the flow of the synovial fluid. The actual geometry where the flow of the synovial fluid takes place is very complicated, and therefore the governing equations are not amenable to simple mathematical analysis. In order to understand the response of the model, we choose to study the flow in a simple geometry. While the flow domain is not a geometry relevant to the flow of the synovial fluid in the human body it yet provides a flow which can be used to assess the efficacy of different models that have been proposed to describe synovial fluids. We study the flow in the annular region between two cylinders, one of which is undergoing unsteady oscillations about their common axis, in order to understand the quintessential behavioral characteristics of the synovial fluid. We use the three models suggested by Hron et al. [ J. Hron, J. M\\'{a}lek, P. Pust\\v{e}jovsk\\'{a}, K. R. Rajagopal, On concentration dependent shear-thinni...

  9. Proceedings of biodegradation

    International Nuclear Information System (INIS)

    This book contains the proceedings of Biodegradation. Topics include:biodegradation using the tools of biotechnology, basic science aspects of biodegradation, the physiological characteristics of microorganisms, the use of selective techniques that enhance the process of microbial evolution of biodegradative genes in nature, the genetic characteristics of microorganisms allowing them to biodegrade both natural and synthetic toxic chemicals, the molecular techniques that allow selective assembly of genetic segments form a variety of bacterial strains to a single strain, and methods needed to advance biodegradation research as well as the high-priority chemical problems important to the Department of Defense or to the chemical industry

  10. Symposium on Short-Term Genetic Bioassays in the Evaluation of Complex Environmental Mixtures

    CERN Document Server

    Sandhu, Shahbeg; Lewtas, Joellen; Claxton, Larry; Strauss, Gary; Nesnow, Stephen

    1985-01-01

    With this proceedings of the fourth symposium on complex mixtures, we continue to revise and extend our knowledge of genetic methods for the evaluation of chemical mixtures in the environment. The early chapters of this volume are devoted to new bioassay techniques that are directly applicable to the monitoring of environments contaminated with genotoxic chemicals. Microbiological methods have been further refined to meet the special needs of atmospheric monitoring so that very small samples may now be efficiently tested. New in situ methods utilizing green plants actually avoid many of the usual difficulties of sample collection and preparation and offer special advantages in monitoring wastewater, sludges, and hazardous wastes. Insects also are being employed very effectively in the evaluation of gaseous air pollutants in controlled laboratory investigations. Increased emphasis has been placed on a comprehensive assessment of the potential of complex mixtures t9 cause various kinds of genetic damage. New as...

  11. The mixture toxicity of environmental contaminants containing sulfonamides and other antibiotics in Escherichia coli: Differences in both the special target proteins of individual chemicals and their effective combined concentration.

    Science.gov (United States)

    Long, Xi; Wang, Dali; Lin, Zhifen; Qin, Mengnan; Song, Chunlei; Liu, Ying

    2016-09-01

    Organisms in the environment are exposed to mixtures of multiple contaminants, leading to serious environmental harm. These mixtures pose an ecological risk and have attracted an increasing amount of attention; however there has been little in-depth research the toxicity of mixtures, such as antibiotics. To determine how different mixtures of antibiotics affect organisms, the individual and mixture toxicity of sulfonamides and several antibiotics were determined using Escherichia coli as a target organism in our study. The results show that additive effects occur between sulfonamides and quinolones or with a portion of β-lactams, synergistic effects appear between sulfonamides and their potentiators or cefotaxime sodium, and antagonistic effects arise between sulfonamides and tetracyclines or penicillin V potassium salt. In addition, the toxicity mechanism of binary mixtures is further discussed and the results reveal that the joint effect differences depend not only the target proteins of individual chemicals but also on their effective combined concentration based on the approach of Quantitative Structure Activity Relationships (QSARs) and molecular docking. This study introduces the concept of the "effective concentration" to provide insight into understanding the mechanism of binary mixtures, which will be beneficial for evaluating the ecological risk of antibiotics. PMID:27269994

  12. A Methodological Approach to Assessing the Health Impact of Environmental Chemical Mixtures: PCBs and Hypertension in the National Health and Nutrition Examination Survey

    Directory of Open Access Journals (Sweden)

    Paul White

    2011-11-01

    Full Text Available We describe an approach to examine the association between exposure to chemical mixtures and a health outcome, using as our case study polychlorinated biphenyls (PCBs and hypertension. The association between serum PCB and hypertension among participants in the 1999–2004 National Health and Nutrition Examination Survey was examined. First, unconditional multivariate logistic regression was used to estimate odds ratios and associated 95% confidence intervals. Next, correlation and multicollinearity among PCB congeners was evaluated, and clustering analyses performed to determine groups of related congeners. Finally, a weighted sum was constructed to represent the relative importance of each congener in relation to hypertension risk. PCB serum concentrations varied by demographic characteristics, and were on average higher among those with hypertension. Logistic regression results showed mixed findings by congener and class. Further analyses identified groupings of correlated PCBs. Using a weighted sum approach to equalize different ranges and potencies, PCBs 66, 101, 118, 128 and 187 were significantly associated with increased risk of hypertension. Epidemiologic data were used to demonstrate an approach to evaluating the association between a complex environmental exposure and health outcome. The complexity of analyzing a large number of related exposures, where each may have different potency and range, are addressed in the context of the association between hypertension risk and exposure to PCBs.

  13. Thermal Modification of a-SiC:H Films Deposited by Plasma Enhanced Chemical Vapour Deposition from CH4+SiH4 Mixtures

    Institute of Scientific and Technical Information of China (English)

    刘玉学; 王宁会; 刘益春; 申德振; 范希武; 李灵燮

    2001-01-01

    The effects of thermal annealing on photoluminescence (PL) and structural properties of a-Si1-xCx :H films deposited by plasma enhanced chemical vapour deposition from CH4+SiH4 mixtures are studied by using infrared, PL and transmittance-reflectance spectra. In a-SiC:H network, high-temperature annealing gives rise to the effusion of hydrogen from strongly bonded hydrogen in SiH, SiH2, (SiH2)n, SiCHn and CHn configurations and the break of weak C-C, Si-Si and C-Si bonds. A structural rearrangement will occur, which causes a significant correlation of the position and intensity of the PL signal with the annealing temperature. The redshift of the PL peak is related to the destruction of the confining power of barriers. However, the PL intensity does not have a significant correlation with the annealing temperature for a C-rich a-SiC:H network, which refers to the formation of π-bond cluster as increasing carbon content. It is indicated that the thermal stability of C-rich a-Si1-xCx:H films is better than that of Si-like a-Si1-xCx :H films.

  14. Effect of deposition temperature on boron-doped carbon coatings deposited from a BCl3-C3H6-H2 mixture using low pressure chemical vapor deposition

    International Nuclear Information System (INIS)

    A mixture of propylene, hydrogen and boron trichloride was used to fabricate boron-doped carbon coatings by using low pressure chemical vapor deposition (LPCVD) technique. Effect of deposition temperature on deposition rate, morphologies, compositions and bonding states of boron-doped carbon coatings was investigated. Below 1273 K, the deposition rate is controlled by reaction dynamics. The deposition rate increases with increasing deposition temperature. The activation energy is 208.74 kJ/mol. Above 1273 K, the deposition rate decreases due to smaller critical radius rc and higher nuclei formation rate J with increasing temperature. Scanning electron microscopy shows that the structure changes from glass-like to nano-laminates with increasing deposition temperature. The boron concentration decreases with increasing deposition temperature, corresponding with increasing carbon concentration. The five types of bonding states are B-C, B-sub-C, BC2O, BCO2 and B-O. B-sub-C and BC2O are the main bonding states. The reactions are dominant at all temperatures, in which the B-sub-C and PyC are formed.

  15. Chemical and Physical Characteristics of Cocopeat-Based Media Mixtures and Their Effects on the Growth and Development of Celosia cristata

    Directory of Open Access Journals (Sweden)

    Yahya Awang

    2009-01-01

    Full Text Available Problem statement: Cocopeat is considered as a good growing media component with acceptable pH, electrical conductivity and other chemical attributes but it has been recognized to have high water holding capacity which causes poor air-water relationship, leading to low aeration within the medium, thus affecting the oxygen diffusion to the roots. Incorporation of coarser materials into cocopeat could improve the aeration status of the media. Approach: Selected chemical and physical characteristics of five types of growing media comprising of (v/v 100% cocopeat, 70% cocopeat: 30% burnt rice hull, 70% cocopeat: 30% perlite, 70% cocopeat: 30% kenaf core fiber and 40% cocopeat: 60% kenaf core fiber were determined and their suitability as growing media was tested using Celosia cristata. Data on pH, Electrical Conductivity (EC and various aspects of air-water relationships of the media, as well on growth and flowering of test plant and leaf nutrient contents were collected. Results: Initial pH for 100% cocopeat and 70% cocopeat: 30% kenaf core fiber was higher than the other media but the values were eventually similar by the end of the study. The bulk density and EC of media containing burnt rice hull was markedly higher than the other media (0.12 g cm3 and 0.48 mS cm-1, respectively. Media comprising of 70% cocopeat: 30% burnt rice hull and 70% cocopeat: 30% perlite contained higher air content. The former held the highest volume of available water. Incorporation of burnt rice hull and perlite into cocopeat increased water absorption ability of the media which reached saturation earlier than the other media. Addition of burnt rice hull (30%, perlite (30% and kenaf core fiber (30% to cocopeat elevated the Air-Filled Porosity (AFP of the media. The growth and flowering of Celosia cristata were the greatest when grown in a mixture of 70% cocopeat: 30% burnt rice hull and perhaps linked with a good balance

  16. CNA proceedings

    International Nuclear Information System (INIS)

    The proceedings comprise keynote addresses, biographies, and 22 papers organized under the following headings: international CANDU operations, challenges in the uranium industry, public acceptance - gaining support, strategies for success in the nuclear business, nuclear power and the environment, initiatives in nuclear regulation, other opportunities. Individual papers published which come within the scope of INIS have been abstracted separately

  17. On the predictive capabilities of CPA for applications in the chemical industry: Mulficomponent mixtures containing methyl-methacrylate, dimethyl-ether or acetic acid

    DEFF Research Database (Denmark)

    Tsivintzelis, Ioannis; Kontogeorgis, Georgios

    2014-01-01

    with acetic acid, esters, ethers and alcohols, and in this case for water-acetic acid the CPA-Huron Vidal (CPA-HV) version of the model is used. For the latter binary mixture, new CPA-HV binary parameter sets are estimated using, among others, data for activity coefficients at infinite dilutions. The...... recommended at the end for modeling ternary or multicomponent mixtures containing acetic acid and water....... mixtures exhibiting vapor-liquid (VLE) and/or liquid-liquid (LLE) equilibrium. The first two cases include mixtures of methyl-methacrylate with acetone or methanol and dimethyl-ether with ethanol, respectively. In these two cases, the classical form of CPA is used. The third case involves aqueous mixtures...

  18. Challenges in Regulating Pesticide Mixtures

    OpenAIRE

    Debra Denton; Bruce Hammock; Craig Wheelock; Jason Belden; Michael Lydy

    2004-01-01

    This paper introduces the field of mixture toxicity and the challenges in regulating pesticide mixtures. Even though pesticides are unique chemical stressors designed to have biological activity that can affect a number of nontarget species, they are intentionally placed into the environment in large quantities. Currently, methods and terminology for evaluating mixture toxicity are poorly established. The most common approach used is the assumption of additive concentration, with the concentr...

  19. CHEMICALS

    CERN Multimedia

    Medical Service

    2002-01-01

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

  20. The properties of the mixture of beef tallow and rapeseed oil with a high content of tallow after chemical and enzymatic interesterification

    Directory of Open Access Journals (Sweden)

    Gruczynska, Eliza

    2005-12-01

    Full Text Available A mixture of beef tallow with rapeseed oil (3:1 wt/wt was interesterified using sodium metoxide or immobilized lipases from Rhizomucor miehei (Lipozyme IM and Candida antarctica (Novozym 435 as catalysts. Chemical interesterifications were carried out at 60 and 90 ºC for 0.5 and 1.5 h using 0.4, 0.6 and 1.0 wt-% CH3ONa. Depending on the catalyst used enzymatic interesterifications were carried out at 60 ºC for 8 h (Lipozyme IM or at 80 ºC for 4 h (Novozym 435. The catalysts doses were kept constant (8 % but the water content in catalysts varied from 2 to 10 %. The starting mixture and the interesterified products were separated by column chromatography into a pure triacylglycerol fraction and a non-triacylglycerol fraction, which contained free fatty acids, mono- and diacylglycerols. It was found that the concentrations of free fatty acids and partial acylglycerols increased after interesterification. The slip melting points and solid fat contents of the triacylglycerol fractions isolated from interesterified fats were lower when compared with nonesterified blends. The sn-2 and sn-1,3 distributions of fatty acids in the triacylglycerol fractions before and after interesterification were determined.These distributions were random after chemical interesterification and near random when Novozym 435 was used. When Lipozyme IM was used, the fatty acid composition at the sn-2 position remained practically unchanged compared with the starting blend. The interesterified fats and isolated triacylglycerols had reduced oxidative stability, as assessed by Rancimat induction times. The addition of 0.02 % of BHA or BHT to the interesterified fats improved their stabilitie.Una mezcla de sebo con aceite de colza (3:1 p/p fue interesterificada usando metóxido de sodio y lipasas inmovilizadas de Rhizomucor miehei (Lipozyme IM and Candida antarctica (Novozym 435 como catalizadores. La interesterificación química se llevó a cabo a 60 ºC y 90

  1. Conference Proceedings

    International Nuclear Information System (INIS)

    This volume contains the unedited proceedings of the Second Annual Conference on Managing Electricity Price Volatility. There were a total of eleven papers presented, dealing with a variety of issues affecting price volatility. Subjects treated included: new power generation development in Alberta; an analysis of electricity supply and demand to predict future price volatility; the effect of government intervention in the Alberta electricity market; risk management in volatile energy markets; an analysis of Alberta's capacity to supply its own internal electric power needs; the impact of increased electricity import and export capacity on price fluctuation in Alberta; improving market liquidity in Alberta; using weather derivatives to offset price risk; the impact of natural gas prices on electricity price volatility; capitalizing on advancements in online trading; and strategies for businesses to keep operating through times of price volatility. In most cases only overhead viewgraphs are available

  2. Chemical networks*

    OpenAIRE

    Thi Wing-Fai

    2015-01-01

    This chapter discusses the fundamental ideas of how chemical networks are build, their strengths and limitations. The chemical reactions that occur in disks combine the cold phase reactions used to model cold molecular clouds with the hot chemistry applied to planetary atmosphere models. With a general understanding of the different types of reactions that can occur, one can proceed in building a network of chemical reactions and use it to explain the abundance of species seen in disks. One o...

  3. Conference Proceedings

    Energy Technology Data Exchange (ETDEWEB)

    Colman, B. [ed.

    1998-06-01

    Invited reviews and contributed papers comprise the Proceedings of the 3. International Symposium on Inorganic Carbon Acquisition by Aquatic Photosynthetic Organisms, held on the campus of the University of British Columbia from 28. July to 1. August 1998. The symposium was attended by 70 participants from Australia, Canada, Israel, Japan, the United States, and several western European countries, to discuss the unique problems of microorganisms in aquatic environments, particularly in the acquisition of inorganic carbon to support photosynthesis. It is known that aquatic microorganisms must obtain inorganic carbon from a medium where dissolved carbon dioxide is often present in limiting concentrations. Despite these limitations, evidence is widely available to show that aquatic plants can build up high intracellular concentrations of inorganic carbon under carbon-limited conditions that enable these plants to reduce or suppress photorespiration, a major source of carbon dioxide in C{sub 3} plants growing under carbon-limiting conditions. This active accumulation of carbon has been described as a carbon dioxide concentration mechanism (CCM). Papers at this symposium document advances in the physiology of inorganic carbon transport systems and their regulation in green algae, especially cyanobacteria, mechanisms of carbon acquisition, and ecological implications of CCMs and their role in the global carbon cycle.

  4. Investigation of structural and chemical transitions in copper oxide microstructures produced by combustion waves in a mixture of CuO-Cu2O-Cu and fuel

    Science.gov (United States)

    Hwang, Hayoung; Lee, Kang Yeol; Yeo, Taehan; Choi, Wonjoon

    2015-12-01

    The application of micro/nanostructured materials to combustion enables distinctive chemical reactions that can be used to modulate the reaction rates. Simultaneously, combustion is capable of changing the intrinsic properties of micro/nanostructured materials based on chemical interactions in high-temperature conditions. In this work, we investigate the structural-chemical transition of copper oxide microstructures exposed to interfacially driven combustion waves. The high thermal energy and exchange of chemical compounds resulting from the instant combustion waves cause direct transition without any further processes. The precise characterization of the structural and chemical transitions in the copper oxide microstructures and chemical fuels confirm that the self-propagating combustion waves in the layered composites of Cu/Cu2O/CuO microparticle-based films and the chemical fuel layers yield the direct synthesis of Cu(OH)2 flower-like structures and nanowires. The propagation of combustion waves at the interface induces an increase of the surface temperatures over 650 °C and the direct interaction between the copper oxide and chemical compounds of the fuel layers. Further application of these interfacially driven combustion waves will contribute to the development of one-step, fast, low-cost methods for the synthesis of micro/nanostructured materials.

  5. Proceedings of the geosciences workshop

    Energy Technology Data Exchange (ETDEWEB)

    None

    1991-01-01

    The manuscripts in these proceedings represent current understanding of geologic issues associated with the Weldon Spring Site Remedial Action Project (WSSRAP). The Weldon Spring site is in St. Charles County, Missouri. The proceedings are the record of the information presented during the WSSRAP Geosciences Workshop conducted on February 21, 1991. The objective of the workshop and proceedings is to provide the public and scientific community with technical information that will facilitate a common understanding of the geology of the Weldon Spring site, of the studies that have been and will be conducted, and of the issues associated with current and planned activities at the site. This coverage of geologic topics is part of the US Department of Energy overall program to keep the public fully informed of the status of the project and to address public concerns as we clean up the site and work toward the eventual release of the property for use by this and future generations. Papers in these proceedings detail the geology and hydrology of the site. The mission of the WSSRAP derives from the US Department of Energy's Surplus Facilities Management Program. The WSSRAP will eliminate potential hazards to the public and the environment and make surplus real property available for other uses to the extent possible. This will be accomplished by conducting remedial actions which will place the quarry, the raffinate pits, the chemical plant, and the vicinity properties in a radiologically and chemically safe condition. The individual papers have been catalogued separately.

  6. Solubility and physic-chemical properties of NaH2PO4 in phosphoric acid, sodium chloride and their mixture solutions at T = (298.15 and 313.15) K

    International Nuclear Information System (INIS)

    Highlights: • Solubility and physic-chemical properties of NaH2PO4 in H3PO4 solutions were obtained. • Solubility and physic-chemical properties of NaH2PO4 in NaCl solutions were obtained were obtained. • Solubility and physic-chemical properties of NaH2PO4 in mixed solutions of H3PO4 and NaCl were obtained. • The solubility diagrams and the physic-chemical property diagrams were plotted. - Abstract: In this study, solubility and physic-chemical properties of sodium dihydrogen phosphate in sodium chloride, phosphoric acid and their mixture solutions at T = (298.15 and 313.15) K have been investigated by using isothermal dissolution method. In the three systems, the solubility of NaH2PO4 always increases with the temperature increasing and decreases with molar concentration of phosphoric acid (sodium chloride) increasing because of the same ion effect. Solubility data of sodium dihydrogen phosphate in the mixed solution of sodium chloride and phosphoric acid is basically required for designing and optimizing the solvent extraction process in the industrial production

  7. Chemical and microbiological assessments of the multi mixture treated by gamma radiation; Avaliacao quimica e microbiologica da multimistura tratada por irradiacao gama

    Energy Technology Data Exchange (ETDEWEB)

    Goncalves, Cinthia Graciele

    2008-07-01

    In Brazil, the multi mixture have being used since the eighties as an alternative against severe infantile malnutrition of the poorest population. However, its use is still reason of controversies mainly due to: the presence of anti nutritional factors, the microbiological quality and the nutritional value. Considering the routine use of multi mixture in the region, this work aimed to evaluate samples of multi mixture were collected in the metropolitan area of the City of Belo Horizonte/MG for determining the anti nutritional factors (phytic and oxalic acids), the microbiological quality, the centesimal and mineral composition, and still the induced effect in these factors of the gamma radiation. For the analyses, the samples passed by the process of gamma irradiation at doses of: 2, 4, 6, 8 and 10 kGy and then were evaluated anti nutritional factors (phytic acid and oxalic), the microbiological quality (yeasts and molds, Salmonella, Coagulase positive Staphylococcus, Bacillus cereus, coliform to 45 deg C) to full percentage (moisture, ash, proteins, carbohydrates and lipids) and the efficiency of the method of Paramagnetic Electronic Resonance (EPR) in the detection of irradiated samples. The mineral composition of the samples was carried out by the irradiation by Neutronic Activation. The methods used were searched in literature. The obtained results suggest that the concentration of the phytic and oxalic acids can not be appropriated for the children with severe nutritional deficit and that it would be necessary additional control in their daily ingestion due to the absorption of essential minerals. In general the samples had presented acceptable microbiological quality for consumption, except by one of it. The data of the centesimal and mineral composition, in the usually recommended portions, showed lower concentration than recommended for children. Any significant alteration in phytic and oxalic acids as well as in the centesimal composition were detected

  8. Distributed estimation of mixture models

    Czech Academy of Sciences Publication Activity Database

    Dedecius, Kamil; Reichl, Jan

    Cham : Springer, 2015 - (Frühwirth-Schnatter, S.; Bitto, A.; Kastner, G.; Posekany, A.), s. 27-36 ISBN 978-3-319-16237-9. - (Springer proceedings in mathematics & statistics). [Bayesian Young Statisticians Meeting (BAYSM 2014) /2./. Vienna (AT), 18.09.2014-19.09.2014] R&D Projects: GA ČR(CZ) GP14-06678P Institutional support: RVO:67985556 Keywords : mixture estimation * distributed estimation * quasi-Bayesian estimation Subject RIV: BB - Applied Statistics, Operational Research http://library.utia.cas.cz/separaty/2015/AS/dedecius-0445781.pdf

  9. Optical pumping of chemical HF lasers on the basis of NF3-H2 and ClF5-H2 mixtures by an open surface discharge in the bleaching-wave mode

    International Nuclear Information System (INIS)

    Lasing on HF upon optical pumping by emission of an open discharge, using NF3 and ClF5 as donors of fluorine atoms, was obtained for the first time in a chemical laser and the bleaching-wave mode was realised in a chemical HF laser. An open surface discharge was used as a pump source. The velocity of the bleaching wave, which was formed under its action, reached ∼8 km s-1. The formation of this wave leads to a rapid (with an ultrasonic velocity) replacement of the working medium in the lasing region, which provides a quantum laser efficiency close to unity. The optimum compo-sition of the working mixture was found to be NF3:H2:Kr =6:10:125 Torr. For this composition, the output laser energy in a 3.2-μs pulse reached ∼0.4 J and the specific output energy was 3.5 J litre-1. Approximately the same output characteristics of laser emission (0.35 J in a 3.5-μs pulse in the ClF5:H2:Kr=3:20:50 Torr mixture) were obtained in the system using ClF5 as donors of fluorine atoms. (lasers, active media)

  10. Quantitative structure-activity relationships and toxicity studies of mixtures of chemicals with anaesthetic potency: Acute lethal and sublethal toxicity to Daphnia magna

    NARCIS (Netherlands)

    Hermens, J.L.M.; Canton, H.; Janssen, P.; Jong, R. de

    1984-01-01

    In this study quantitative structure-activity relationships (QSARs) were calculated between hydrophobicity of a group of organic chemicals with anaesthetic potency and toxicity (immobilization, mortality and inhibition of reproduction) to Daphnia magna. Differences in slopes of the high quality QSAR

  11. EFFECTS OF SIMPLIFIED CHEMICAL KINETIC MODEL ON THE MICRO-FLAME STRUCTURE AND TEMPERATURE OF THE LEAN PREMIXED METHANE-AIR MIXTURES

    Directory of Open Access Journals (Sweden)

    JUNJIE CHEN

    2015-07-01

    Full Text Available The effect of simplified chemical kinetic model on the micro-flame structure, central axis and wall temperatures were investigated with different one-step global chemical kinetic mechanisms following Mantel, Duterque and Fernández-Tarrazo models. Numerical investigations of the premixed methane-air flame in the micro-channel and lean conditions were carried out to compare and analyze the effect of the comprehensive chemical kinetic mechanisms. The results indicate that one-step global chemical kinetic mechanism affects both the micro-flame shape and the combustion temperature. Among three simulation models, Mantel model allows a stable micro-flame with a bamboo shoot form, which anchor at the inlet. Duterque model gives a stable elongated micro-flame with a considerable ignition delay, and a dead zone with fluid accumulation is observed at the entrance, which may explain the very high combustion temperature and the fast reaction rate obtained, despite the micro-flame development presents a very hot spot and causes a broadening of the combustion zone. Fernández-Tarrazo model results in a rapid extinction and doesn't seem to take all the kinetic behavior into account for the appropriate micro-combustion simulations.

  12. Toxicity of environmental chemicals and their mixtures to selected aquatic organisms. Behaviour, development and biochemistry; Toxizitaet von Umweltchemikalien und deren Mischungen auf ausgewaehlte aquatische Organismen. Verhalten, Entwicklung und Biochemie

    Energy Technology Data Exchange (ETDEWEB)

    Kienle, Cornelia

    2009-04-28

    , relevant and sensitive parameters for the different research topics/questions in the present work, and can also be recommended to be used to analyse interspecific interactions. To judge on the effects of pollutants on aquatic organisms in the environment, abiotic parameters as well as mixtures of pollutants should be included. Additionally, biochemical measurements as well as behavioural tests are important, to adequately assess the toxicity of pollutants. Therefore, for an integrated understanding of the effects of chemicals on aquatic organisms, a battery of different methods as well as more realistic exposure scenarios should be taken into account. (orig.)

  13. Effect of thiram and of a hydrocarbon mixture on freshwater macroinvertebrate communities in outdoor stream and pond mesocosms: I. Study design, chemicals fate and structural responses.

    Science.gov (United States)

    Bayona, Yannick; Roucaute, Marc; Cailleaud, Kevin; Lagadic, Laurent; Bassères, Anne; Caquet, Thierry

    2015-11-01

    Higher-tier ecological risk assessment (ERA) in mesocosms is commonly performed in lotic or lentic experimental systems. These systems differ in their physico-chemical and hydrological properties, leading to differences in chemical fate, community characteristics and potential recovery. This raises the issue of the relevance and sensitivity of community-level endpoints in different types of mesocosms. In this study, macroinvertebrate abundance and biomass estimates were used to assess the effects of a dithiocarbamate fungicide, thiram (35 and 170 µg l(-1)), and a petroleum middle distillate (PMD; 0.01, 0.4, 2 and 20 mg l(-1)) in outdoor stream and pond mesocosms. Streams were continuously treated during 3 weeks followed by a 2-month long post-treatment period. Ponds were treated weekly for 4 weeks, followed by a 10-month long post-treatment period. Taxonomic structure of macroinvertebrate communities was characterized using the α, β and γ components of taxa richness, Shannon and Gini-Simpson indices. Computations were based either on abundance or biomass data. Results clearly highlighted that the effects of chemicals depended on the exposure regime (for thiram) and type of system (for the PMD). Causes of the differences between streams and ponds in the magnitude and nature of effects include differential sensitivity of taxa dwelling in lentic and lotic systems and the influence of hydrology (e.g., drift from upstream) and mesocosm connectivity on recovery dynamics. This study also showed complementarities in the use of both types of mesocosms to improve the characterization of chemical effects on communities in ERA. PMID:26385344

  14. Probabilistic human health risk assessment of degradation-related chemical mixtures in heterogeneous aquifers: risk statistics, hot spots, and preferential channels

    OpenAIRE

    Henri, Christopher Vincent; Fernández García, Daniel; Barros, Felipe de

    2015-01-01

    The increasing presence of toxic chemicals released in the subsurface has led to a rapid growth of social concerns and the need to develop and employ models that can predict the impact of groundwater contamination on human health risk under uncertainty. Monitored natural attenuation is a common remediation action in many contamination cases. However, natural attenuation can lead to the production of daughter species of distinct toxicity that may pose challenges in pollution management strateg...

  15. Effect of water glass modification with nanoparticles of zinc oxide on selected physical and chemical properties of binder and mechanical properties of sand mixture

    Directory of Open Access Journals (Sweden)

    A. Kmita

    2012-12-01

    Full Text Available In this paper, an attempt was made to use the ZnO nanoparticles as a modifier of foundry binder - water glass. The modifier was a colloidal suspension of the ZnO zinc oxide nanoparticles in propanol. A thermal method to obtain metal oxide nanoparticles was adopted. The modifier was product of the thermal decomposition of the basic zinc carbonate ([ZnCO3]2•[Zn(OH2]3, and was introduced into the water glass in an amount of 1 and 3 wt%. To determine the interfacial reactions taking place in a quartz - modified water glass system, the binder wettability of the quartz grains was measured. The effect of water glass modification on the mechanical properties of moulding sands was verified by testing the tensile strength Rm u of moulding sands with the modified binders. Water glass modification with the colloidal solution of ZnO nanoparticles in propanol confirmed the effect of modifier on the water glass wettability of sand grains and on the mechanical properties of the sand mixtures with this additive.

  16. Chemical characterization of fatty acids, alkanes, n-diols and alkyl esters produced by a mixed culture of Trichoderma koningii and Penicillium janthinellum grown aerobically on undecanoic acid, potatoe dextrose and their mixture.

    Science.gov (United States)

    Monreal, Carlos M; Chahal, Amarpreet; Schnitzer, Morris; Rowland, Owen

    2016-05-01

    Little is known about the mixed fungal synthesis of high-value aliphatics derived from the metabolism of simple and complex carbon substrates. Trichoderma koningii and Penicillium janthinellum were fed with undecanoic acid (UDA), potatoe dextrose broth (PDB), and their mixture. Pyrolysis Field Ionization Mass Spectrometry (Py-FIMS) together with (1)H and (13)C Nuclear Magnetic Resonance (NMR) characterized CHCl3 soluble aliphatics in the fungal cell culture. Data from NMR and Py-FIMS analysis were complementary to each other. On average, the mixed fungal species produced mostly fatty acids (28% of total ion intensity, TII) > alkanes (2% of TII) > n-diols (2% of TII) > and alkyl esters (0.8% of TII) when fed with UDA, PDB or UDA+PDB. The cell culture accumulated aliphatics extracellularly, although most of the identified compounds accumulated intracellularly. The mixed fungal culture produced high-value chemicals from the metabolic conversion of simple and complex carbon substrates. PMID:26852878

  17. Uso de misturas químicas para a manutenção da firmeza de banana 'Prata' minimamente processada Use of chemical mixtures for firmness maintenance of fresh-cut 'Silver' banana

    Directory of Open Access Journals (Sweden)

    Eduardo Valério de Barros Vilas Boas

    2009-02-01

    Full Text Available A banana constitui interessante alternativa para compor saladas de frutas. No entanto, possui curta vida de prateleira após o processamento mínimo em razão da rápida perda da firmeza. Neste trabalho, objetivou-se avaliar o efeito da mistura química contendo cloreto de cálcio, ácido ascórbico e L-cisteína e/com o uso de atmosfera modificada ativa (10 kPa CO2 e 2 kPa O2, enfatizando a perda de firmeza sobre a qualidade e vida de prateleira de banana 'Prata' minimamente processada. O conteúdo de pectina solúvel e a % de solubilização aumentaram significativamente ao longo do período de conservação. A perda de firmeza e o aumento das atividades das enzimas poligalacturonase e pectinametilesterase apresentaram uma interação significativa entre os fatores estudados (Tratamento/Tempo. As fatias tratadas com misturas químicas permaneceram com boas características para o consumo por até 3 dias de conservação. Os tratamentos com injeção inicial de gases de forma isolada, ou junto ao tratamento com mistura química, não propiciaram maior retenção da firmeza de banana 'Prata' minimamente processada em relação ao tratamento contendo L-cisteína (1% p/v + ácido ascórbico (1% p/v + cloreto de cálcio (1% p/v na mistura química.Banana constitutes an interesting alternative to make fruit salad. Nevertheless, they have short shelf life after cutting due to the fast loss of firmness. The objective of this work was to evaluate the effect of chemical mixtures containing calcium chloride, ascorbic acid and L-cysteine with the use of active modified atmosphere (10 kPa CO2 and 2 kPa O2, emphasizing the lost of firmness on the quality and shelf life of fresh-cut 'Silver' banana. Soluble pectin content and the percentage of solubilization increased significantly throughout the conservation period. The lost of firmness and the increase of pectinmethylesterase and polygalacturonase activities presented a significant interaction among the

  18. Variational Theory of Mixtures in Continuum Mechanics

    OpenAIRE

    Gouin, Henri

    1990-01-01

    In continuum mechanics, the equations of motion for mixtures are derived through the use of Hamilton's extended principle which regards the mixture as a collection of distinct continua. The internal energy is assumed to be a function of densities, entropies and successive spatial gradients of each constituent. We first write the equations of motion for each constituent of an inviscid miscible mixture of fluids without chemical reactions or diffusion. Our work leads to the equations of motion ...

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

    Science.gov (United States)

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

    2015-07-01

    An analytical method using liquid chromatography coupled to mass spectrometry with atmospheric pressure chemical ionization for the determination of polycyclic aromatic hydrocarbons in asphalt fractions has been developed. The 14 compounds determined, characterized by having two or more condensed aromatic rings, are expected to be present in asphalt and are considered carcinogenic and mutagenic. The parameters of the atmospheric pressure chemical ionization interface were optimized to obtain the highest possible sensitivity for all of the compounds. The limits of detection ranged from 0.5 to 346.5 μg/L and the limits of quantification ranged from 1.7 to 1550 μg/L. The method was validated against a diesel particulate extract standard reference material (NIST SRM 1975), and the obtained concentrations agreed with the certified values. The method was applied to asphalt samples after its fractionation according to ASTM D4124 and the method of Green. The concentrations of the seven polycyclic aromatic hydrocarbons quantified in the sample ranged from 0.86 mg/kg for benzo[ghi]perylene to 98.32 mg/kg for fluorene. PMID:25885756

  20. 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...... 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 for Signal Processing, pp. 15-20, 2005. All files should be in the same directory. The...

  1. Mixture Density Mercer Kernels

    Data.gov (United States)

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

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

    Science.gov (United States)

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

    2015-12-01

    Liquid chromatography coupled to mass spectrometry with atmospheric pressure chemical ionization was used for the determination of polycyclic aromatic hydrocarbon derivatives, the oxygenated polycyclic aromatic hydrocarbons and nitrated polycyclic aromatic hydrocarbons, formed in asphalt fractions. Two different methods have been developed for the determination of five oxygenated and seven nitrated polycyclic aromatic hydrocarbons that are characterized by having two or more condensed aromatic rings and present mutagenic and carcinogenic properties. The parameters of the atmospheric pressure chemical ionization interface were optimized to obtain the highest possible sensitivity for all compounds. The detection limits of the methods ranged from 0.1 to 57.3 μg/L for nitrated and from 0.1 to 6.6 μg/L for oxygenated derivatives. The limits of quantification were in the range of 4.6-191 μg/L for nitrated and 0.3-8.9 μg/L for oxygenated derivatives. The methods were validated against a diesel particulate extract standard reference material (National Institute of Standards and Technology SRM 1975), and the obtained concentrations (two nitrated derivatives) agreed with the certified values. The methods were applied in the analysis of asphalt samples after their fractionation into asphaltenes and maltenes, according to American Society for Testing and Material D4124, where the maltenic fraction was further separated into its basic, acidic, and neutral parts following the method of Green. Only two nitrated derivatives were found in the asphalt sample, quinoline and 2-nitrofluorene, with concentrations of 9.26 and 2146 mg/kg, respectively, whereas no oxygenated derivatives were detected. PMID:26446274

  3. Chemical Sensors – from Molecules, Complex Mixtures to Cells – Supramolecular Imprinting Strategies

    Directory of Open Access Journals (Sweden)

    Christian Palfinger

    2003-09-01

    Full Text Available Methods of modern chemistry are a powerful tool in generating functional materials suitable as chemically sensitive layers to be combined with a variety of transducer principles. Molecular pits in polymers are formed by molecular imprinting, by suitable double-imprinting e.g. PAHs can be detected down to the sub-μg/l level. The resulting selectivity patterns depend both on the polymerization temperature and the template/mononomer composition. Organic contaminants in water can be either directly assessed in liquid phase or separated from the matrix by a porous Teflon membrane. Thus the detection limits can be reduced to the ppm-level due to the a much lower noise level in gaseous phase. Even complex processes such as engine oil degradation can be followed by suitably imprinted polymers. Pits on the nm- to μm scale are reached by surface templating polymers with microorganisms. The resulting layers show reversible, antibody-like interactions and thus are optimal sensor layers. The successful on-line detection of tobacco mosaic viruses (TMV can be achieved by these surface imprinted layers.

  4. Foaming of mixtures of pure hydrocarbons

    Science.gov (United States)

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

    1950-01-01

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

  5. Lipon thin films grown by plasma-enhanced metalorganic chemical vapor deposition in a N{sub 2}-H{sub 2}-Ar gas mixture

    Energy Technology Data Exchange (ETDEWEB)

    Meda, Lamartine, E-mail: LMeda@xula.edu [Department of Chemistry, Xavier University of Louisiana, 1 Drexel Drive, New Orleans, LA, 70125 (United States); Maxie, Eleston E. [Excellatron Solid State LLC, 263 Decatur Street, Atlanta, GA 30312 (United States)

    2012-01-01

    Lithium phosphorus oxynitride (Lipon) thin films have been deposited by a plasma-enhanced metalorganic chemical vapor deposition method. Lipon thin films were deposited on approximately 0.2 {mu}m thick Au-coated alumina substrates in a N{sub 2}-H{sub 2}-Ar plasma at 13.56 MHz, a power of 150 W, and at 180 Degree-Sign C using triethyl phosphate [(CH{sub 2}CH{sub 3}){sub 3}PO{sub 4}] and lithium tert-butoxide [(LiOC(CH{sub 3}){sub 3}] precursors. Lipon growth rates ranged from 10 to 42 nm/min and thicknesses varied from 1 to 2.5 {mu}m. X-ray powder diffraction showed that the films were amorphous, and X-ray photoelectron spectroscopy (XPS) revealed approximately 4 at.% N in the films. The ionic conductivity of Lipon was measured by electrochemical impedance spectroscopy to be approximately 1.02 {mu}S/cm, which is consistent with the ionic conductivity of Lipon deposited by radio frequency magnetron sputtering of Li{sub 3}PO{sub 4} targets in either mixed Ar-N{sub 2} or pure N{sub 2} atmosphere. Attempts to deposit Lipon in a N{sub 2}-O{sub 2}-Ar plasma resulted in the growth of Li{sub 3}PO{sub 4} thin films. The XPS analysis shows no C and N atom peaks. Due to the high impedance of these films, reliable conductivity measurements could not be obtained for films grown in N{sub 2}-O{sub 2}-Ar plasma.

  6. Lipon thin films grown by plasma-enhanced metalorganic chemical vapor deposition in a N2–H2–Ar gas mixture

    International Nuclear Information System (INIS)

    Lithium phosphorus oxynitride (Lipon) thin films have been deposited by a plasma-enhanced metalorganic chemical vapor deposition method. Lipon thin films were deposited on approximately 0.2 μm thick Au-coated alumina substrates in a N2–H2–Ar plasma at 13.56 MHz, a power of 150 W, and at 180 °C using triethyl phosphate [(CH2CH3)3PO4] and lithium tert-butoxide [(LiOC(CH3)3] precursors. Lipon growth rates ranged from 10 to 42 nm/min and thicknesses varied from 1 to 2.5 μm. X-ray powder diffraction showed that the films were amorphous, and X-ray photoelectron spectroscopy (XPS) revealed approximately 4 at.% N in the films. The ionic conductivity of Lipon was measured by electrochemical impedance spectroscopy to be approximately 1.02 μS/cm, which is consistent with the ionic conductivity of Lipon deposited by radio frequency magnetron sputtering of Li3PO4 targets in either mixed Ar–N2 or pure N2 atmosphere. Attempts to deposit Lipon in a N2–O2–Ar plasma resulted in the growth of Li3PO4 thin films. The XPS analysis shows no C and N atom peaks. Due to the high impedance of these films, reliable conductivity measurements could not be obtained for films grown in N2–O2–Ar plasma.

  7. Uranium hexafluoride handling. Proceedings

    Energy Technology Data Exchange (ETDEWEB)

    1991-12-31

    The United States Department of Energy, Oak Ridge Field Office, and Martin Marietta Energy Systems, Inc., are co-sponsoring this Second International Conference on Uranium Hexafluoride Handling. The conference is offered as a forum for the exchange of information and concepts regarding the technical and regulatory issues and the safety aspects which relate to the handling of uranium hexafluoride. Through the papers presented here, we attempt not only to share technological advances and lessons learned, but also to demonstrate that we are concerned about the health and safety of our workers and the public, and are good stewards of the environment in which we all work and live. These proceedings are a compilation of the work of many experts in that phase of world-wide industry which comprises the nuclear fuel cycle. Their experience spans the entire range over which uranium hexafluoride is involved in the fuel cycle, from the production of UF{sub 6} from the naturally-occurring oxide to its re-conversion to oxide for reactor fuels. The papers furnish insights into the chemical, physical, and nuclear properties of uranium hexafluoride as they influence its transport, storage, and the design and operation of plant-scale facilities for production, processing, and conversion to oxide. The papers demonstrate, in an industry often cited for its excellent safety record, continuing efforts to further improve safety in all areas of handling uranium hexafluoride. Selected papers were processed separately for inclusion in the Energy Science and Technology Database.

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

    International Nuclear Information System (INIS)

    CH4 and C2H2 molecules (and their interconversion) in hydrocarbon/rare gas/H2 gas mixtures in a microwave reactor used for plasma enhanced diamond chemical vapor deposition (CVD) have been investigated by line-of-sight infrared absorption spectroscopy in the wavenumber range of 1276.5-1273.1 cm-1 using a quantum cascade laser spectrometer. Parameters explored include process conditions [pressure, input power, source hydrocarbon, rare gas (Ar or Ne), input gas mixing ratio], height (z) above the substrate, and time (t) after addition of hydrocarbon to a pre-existing Ar/H2 plasma. The line integrated absorptions so obtained have been converted to species number densities by reference to the companion two-dimensional (r,z) modeling of the CVD reactor described in Mankelevich et al. [J. Appl. Phys. 104, 113304 (2008)]. The gas temperature distribution within the reactor ensures that the measured absorptions are dominated by CH4 and C2H2 molecules in the cool periphery of the reactor. Nonetheless, the measurements prove to be of enormous value in testing, tensioning, and confirming the model predictions. Under standard process conditions, the study confirms that all hydrocarbon source gases investigated (methane, acetylene, ethane, propyne, propane, and butane) are converted into a mixture dominated by CH4 and C2H2. The interconversion between these two species is highly dependent on the local gas temperature and the H atom number density, and thus on position within the reactor. CH4→C2H2 conversion occurs most efficiently in an annular shell around the central plasma (characterized by 1400gas2H2→CH4 is favored in the more distant regions where Tgas4→C2H2 conversion, whereas the reverse C2H2→CH4 process only requires H atoms to drive the reactions; H atoms are not consumed by the overall conversion.

  9. Proceedings of the Jorge Andre Swieca Summer School; 4. Experimental Nuclear Physics Session

    International Nuclear Information System (INIS)

    These proceedings present works on experimental nuclear physics, activation analysis, nuclear interactions, neutron physics, nuclear moments, inelastic scattering, lattices and chemical analysis. (L.C.J.A.)

  10. Effects of radio-frequency power on the properties of carbon thin films prepared by thermal chemical vapor deposition enhanced with remote inductively-coupled-plasma using acetylene/nitrogen mixtures

    International Nuclear Information System (INIS)

    The effects of radio-frequency (rf) power on the properties of carbon thin films prepared by thermal chemical vapor deposition (CVD) enhanced with remote inductively-coupled-plasma (ICP) are investigated. Acetylene and nitrogen were used as the precursor gases, and rf-powers of ICP were set as 0, 100, 200, 300, and 400 W. The deposition temperature, working pressure, and deposition time were set as 1248 K, 4 kPa, and 2 h, respectively. The residual gases, film thicknesses, microstructures, chemical characteristics, mechanical properties, and electrical properties of carbon thin films were investigated by residual gas analyzer (RGA), field emission scanning electron microscopy, X-ray diffractometer (and Raman scattering spectrometer), X-ray photoelectron spectrometer, nanoindenter, and four point probe, respectively. RGA results reveal that the main species in the gas phase contain H2, C2H, C2H2, HCN (or C2H3), and N2 (or C2H4). Moreover, C2H, C2H2, and C2H4 can be speculated as the main species for carbon thin film deposition. As the rf-power increases from 0 to 400 W, the deposition rate of carbon thin films decreases from 204 to 36.0 nm/h. The crystallinity and ordering degree of carbon thin films increase with increasing rf-power from 0 to 400 W, but the ratio of sp2 carbon sites in carbon thin films decreases from 95 to 75%. The Young's modulus, hardness, and electrical resistivity of carbon thin films increase with increasing rf-power. Furthermore, the effects of rf-power on the deposition rates of carbon thin films prepared by thermal CVD enhanced with remote ICP using C2H2/N2 and CH4/N2 mixtures are compared. - Highlights: • Carbon films are prepared by TCVD enhanced with remote ICP using C2H2/N2 mixtures. • The deposition rate of carbon thin films decreases with increasing the rf-power. • C2H, C2H2, and C2H4 are speculated as the main species for carbon film deposition. • The sp2 sites in carbon thin films decrease with increasing rf-power.

  11. 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...

  12. Simultaneous and selective decarboxylation of L-serine and deamination of L-phenylalanine in an amino acid mixture--a means of separating amino acids for synthesizing biobased chemicals.

    Science.gov (United States)

    Teng, Yinglai; Scott, Elinor L; Witte-van Dijk, Susan C M; Sanders, Johan P M

    2016-01-25

    Amino acids (AAs) obtained from the hydrolysis of biomass-derived proteins are interesting feedstocks for the chemical industry. They can be prepared from the byproduct of biofuel production and agricultural wastes. They are rich in functionalities needed in petrochemicals, providing the opportunity to save energy, reagents, and process steps. However, their separation is required before they can be applied for further applications. Electrodialysis (ED) is a promising separation method, but its efficiency needs to be improved when separating AAs with similar isoelectric points. Thus, specific conversions are required to form product with different charges. Here we studied the enzymatic conversions which can be used as a means to aid the ED separation of neutral AAs. A model mixture containing L-serine, L-phenylalanine and L-methionine was used. The reactions of L-serine decarboxylase and L-phenylalanine ammonia-lyase were employed to specifically convert serine and phenylalanine into ethanolamine and trans-cinnamic acid. At the isoelectric point of methionine (pH 5.74), the charge of ethanolamine and trans-cinnamic acid are +1 and -1, therefore facilitating potential separation into three different streams by electrodialysis. Here the enzyme kinetics, specificity, inhibition and the operational stabilities were studied, showing that both enzymes can be applied simultaneously to aid the ED separation of neutral AAs. PMID:25976628

  13. Low temperature asphalt mixtures

    OpenAIRE

    Modrijan, Damjan

    2006-01-01

    This thesis presents the problem of manufacturing and building in the asphalt mixtures produced by the classical hot procedure and the possibility of manufacturing low temperature asphalt mixtures.We will see the main advantages of low temperature asphalt mixtures prepared with bitumen with organic addition Sasobit and compare it to the classical asphalt mixtures. The advantages and disadvantages of that are valued in the practical example in the conclusion.

  14. Purging mixture for extruder

    OpenAIRE

    Okpala, Chukwubuike

    2015-01-01

    This thesis work focuses on compounding a mechanical purge mixture for extruders. The base resin for making the purge mixture is recycled High Density Polyethylene chosen for its high density and good processing temperature. The additives are mainly clay and sili-con dioxide added as filler and scrubbing materials respectively. The purge mixture was produced by mixing the base resin and additives in percentage ratios into five places la-beled A, B, C, D, and E. the mixtures were extruded and ...

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

    Science.gov (United States)

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

    2009-08-01

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

  16. Radiofrequency plasma heating: proceedings

    International Nuclear Information System (INIS)

    The conference proceedings include sessions on Alfven Wave Heating, ICRF Heating and Current Drive, Lower Hybrid Heating and Current Drive, and ECRF Heating. Questions of confinement, diagnostics, instabilities and technology are considered. Individual papers are cataloged separately

  17. IPHE Infrastructure Workshop Proceedings

    Energy Technology Data Exchange (ETDEWEB)

    None

    2010-02-01

    This proceedings contains information from the IPHE Infrastructure Workshop, a two-day interactive workshop held on February 25-26, 2010, to explore the market implementation needs for hydrogen fueling station development.

  18. A Novel Approach for Evaluating Carbamate Mixtures for Dose Additivity

    Science.gov (United States)

    Two mathematical approaches were used to test the hypothesis ofdose-addition for a binary and a seven-chemical mixture ofN-methyl carbamates, toxicologically similar chemicals that inhibit cholinesterase (ChE). In the more novel approach, mixture data were not included in the ana...

  19. 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

  20. Characterization of bioactive mixtures oligogalacturonidos

    International Nuclear Information System (INIS)

    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

  1. Thermodynamic scheme of inhomogeneous perfect fluid mixtures

    OpenAIRE

    Zarate, R D; Quevedo, Hernando

    2004-01-01

    We analyze the compatibility between the geometrodynamics and thermodynamics of a binary mixture of perfect fluids which describe inhomogeneous cosmological models. We generalize the thermodynamic scheme of general relativity to include the chemical potential of the fluid mixture with non-vanishing entropy production. This formalism is then applied to the case of Szekeres and Stephani families of cosmological models. The compatibility conditions turn out to impose symmetry conditions on the c...

  2. Effects of radio-frequency power on the properties of carbon thin films prepared by thermal chemical vapor deposition enhanced with remote inductively-coupled-plasma using acetylene/nitrogen mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Lai, Liang-Hsun; Wu, Kuan-Chang; Shiue, Sham-Tsong, E-mail: stshiue@dragon.nchu.edu.tw

    2014-11-03

    The effects of radio-frequency (rf) power on the properties of carbon thin films prepared by thermal chemical vapor deposition (CVD) enhanced with remote inductively-coupled-plasma (ICP) are investigated. Acetylene and nitrogen were used as the precursor gases, and rf-powers of ICP were set as 0, 100, 200, 300, and 400 W. The deposition temperature, working pressure, and deposition time were set as 1248 K, 4 kPa, and 2 h, respectively. The residual gases, film thicknesses, microstructures, chemical characteristics, mechanical properties, and electrical properties of carbon thin films were investigated by residual gas analyzer (RGA), field emission scanning electron microscopy, X-ray diffractometer (and Raman scattering spectrometer), X-ray photoelectron spectrometer, nanoindenter, and four point probe, respectively. RGA results reveal that the main species in the gas phase contain H{sub 2}, C{sub 2}H, C{sub 2}H{sub 2}, HCN (or C{sub 2}H{sub 3}), and N{sub 2} (or C{sub 2}H{sub 4}). Moreover, C{sub 2}H, C{sub 2}H{sub 2}, and C{sub 2}H{sub 4} can be speculated as the main species for carbon thin film deposition. As the rf-power increases from 0 to 400 W, the deposition rate of carbon thin films decreases from 204 to 36.0 nm/h. The crystallinity and ordering degree of carbon thin films increase with increasing rf-power from 0 to 400 W, but the ratio of sp{sup 2} carbon sites in carbon thin films decreases from 95 to 75%. The Young's modulus, hardness, and electrical resistivity of carbon thin films increase with increasing rf-power. Furthermore, the effects of rf-power on the deposition rates of carbon thin films prepared by thermal CVD enhanced with remote ICP using C{sub 2}H{sub 2}/N{sub 2} and CH{sub 4}/N{sub 2} mixtures are compared. - Highlights: • Carbon films are prepared by TCVD enhanced with remote ICP using C{sub 2}H{sub 2}/N{sub 2} mixtures. • The deposition rate of carbon thin films decreases with increasing the rf-power. • C{sub 2}H, C{sub 2}H

  3. 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.

  4. Systems and methods for removing components of a gas mixture

    Energy Technology Data Exchange (ETDEWEB)

    None

    2016-09-06

    A system for removing components of a gaseous mixture is provided comprising: a reactor fluid containing vessel having conduits extending therefrom, aqueous fluid within the reactor, the fluid containing a ligand and a metal, and at least one reactive surface within the vessel coupled to a power source. A method for removing a component from a gaseous mixture is provided comprising exposing the gaseous mixture to a fluid containing a ligand and a reactive metal, the exposing chemically binding the component of the gaseous mixture to the ligand. A method of capturing a component of a gaseous mixture is provided comprising: exposing the gaseous mixture to a fluid containing a ligand and a reactive metal, the exposing chemically binding the component of the gaseous mixture to the ligand, altering the oxidation state of the metal, the altering unbinding the component from the ligand, and capturing the component.

  5. Thermodiffusion in binary and ternary nonpolar hydrocarbon + alcohol mixtures

    Science.gov (United States)

    Eslamian, Morteza; Saghir, M. Ziad

    2012-12-01

    Thermodiffusion in complex mixtures, such as associating, molten metal, and polymer mixtures is difficult to model usually owing to the occurrence of a sign change in the thermodiffusion coefficient when the mixture concentration and temperature change. A mixture comprised of a nonpolar hydrocarbon and an alcohol is a complex and highly non-ideal mixture. In this paper an existing binary non-equilibrium thermodynamics model (Eslamian and Saghir, Physical Review E 80, 061201, 2009) developed for aqueous mixtures of alcohols is examined against the experimental data of binary nonpolar hydrocarbon and alcohol mixtures. For ternary mixtures, non-equilibrium thermodynamic expressions developed by the authors for aqueous mixtures of alcohols (Eslamian and Saghir, Canadian Journal of Chemical Engineering, DOI 10.1002/cjce.20581) is used to predict thermodiffusion coefficients of ternary nonpolar hydrocarbon and alcohol mixtures. The rationale behind the sign change is elucidated and attributed to an anomalous change in the molecular structure and therefore viscosity of such mixtures. Model predictions of thermodiffusion coefficients of binary mixtures predict a sign change consistent with the experimental data although the model is still too primitive to capture all structural complexities. For instance, in the methanol-benzene mixture where the model predictions are poorest, the viscosity data show that when concentration varies, the mixture's molecular structure experiences a severe change twice, the first major change leading to a maximum in the thermodiffusion coefficient, whereas the second change causes a sign change.

  6. Proceedings of the 41. Brazilian congress on ceramics. 2. Congress on ceramics and industrial minerals from MERCOSUL. v. 2

    International Nuclear Information System (INIS)

    These proceedings present theoretical and experimental papers on the following subjects: material characterization, structural analysis, structural chemical analysis, phase studies crystallography, sintering, and material processing

  7. Proceedings of the 41. Brazilian congress on ceramics. 2. Congress on ceramics and industrial minerals from MERCOSUL. v. 1

    International Nuclear Information System (INIS)

    These proceedings present theoretical and experimental papers on the following subjects: material characterization, structural analysis, structural chemical analysis, phase studies crystallography, sintering, and material processing

  8. Hormesis in mixtures -- can it be predicted?

    Science.gov (United States)

    Belz, Regina G; Cedergreen, Nina; Sørensen, Helle

    2008-10-01

    Binary mixture studies are well established for mixtures of pollutants, pesticides, or allelochemicals and sound statistical methods are available to evaluate the results in relation to reference models. The majority of mixture studies are conducted to investigate the effect of one compound on the inhibitory action of another. However, since stimulatory responses to low concentrations of chemicals are gaining increased attention and improved statistical models are available to describe this phenomenon of hormesis, scientists are challenged by the question of what will happen in the low concentration range when all or some of the chemicals in a mixture induce hormesis? Can the mixture effects still be predicted and can the size and concentration range of hormesis be predicted? The present study focused on binary mixtures with one or both compounds inducing hormesis and evaluated six data sets of root length of Lactuca sativa L. and areal growth of Lemna minor L., where substantial and reproducible hormetic responses to allelochemicals and herbicides have been found. Results showed that the concentration giving maximal growth stimulatory effects (M) and the concentration where the hormetic effect had vanished (LDS) could be predicted by the most-used reference model of concentration addition (CA), if the growth inhibitory concentrations (EC50) followed CA. In cases of deviations from CA at EC50, the maximum concentration M and the LDS concentration followed the same deviation patterns, which were described by curved isobole models. Thus, low concentration mixture effects as well as the concentration range of hormesis can be predicted applying available statistical models, if both mixture partners induce hormesis. Using monotonic concentration-response models instead of biphasic concentration-response models for the prediction of joint effects, thus ignoring hormesis, slightly overestimated the deviation from CA at EC20 and EC50, but did not alter the general

  9. I. Cognitive and instructional factors relating to students' development of personal models of chemical systems in the general chemistry laboratory II. Solvation in supercritical carbon dioxide/ethanol mixtures studied by molecular dynamics simulation

    Science.gov (United States)

    Anthony, Seth

    Part I. Students' participation in inquiry-based chemistry laboratory curricula, and, in particular, engagement with key thinking processes in conjunction with these experiences, is linked with success at the difficult task of "transfer"---applying their knowledge in new contexts to solve unfamiliar types of problems. We investigate factors related to classroom experiences, student metacognition, and instructor feedback that may affect students' engagement in key aspects of the Model-Observe-Reflect-Explain (MORE) laboratory curriculum - production of written molecular-level models of chemical systems, describing changes to those models, and supporting those changes with reference to experimental evidence---and related behaviors. Participation in introductory activities that emphasize reviewing and critiquing of sample models and peers' models are associated with improvement in several of these key aspects. When students' self-assessments of the quality of aspects of their models are solicited, students are generally overconfident in the quality of their models, but these self-ratings are also sensitive to the strictness of grades assigned by their instructor. Furthermore, students who produce higher-quality models are also more accurate in their self-assessments, suggesting the importance of self-evaluation as part of the model-writing process. While the written feedback delivered by instructors did not have significant impacts on student model quality or self-assessments, students' resubmissions of models were significantly improved when students received "reflective" feedback prompting them to self-evaluate the quality of their models. Analysis of several case studies indicates that the content and extent of molecular-level ideas expressed in students' models are linked with the depth of discussion and content of discussion that occurred during the laboratory period, with ideas developed or personally committed to by students during the laboratory period being

  10. Chemical networks

    Science.gov (United States)

    Thi, Wing-Fai

    2015-09-01

    This chapter discusses the fundamental ideas of how chemical networks are build, their strengths and limitations. The chemical reactions that occur in disks combine the cold phase reactions used to model cold molecular clouds with the hot chemistry applied to planetary atmosphere models. With a general understanding of the different types of reactions that can occur, one can proceed in building a network of chemical reactions and use it to explain the abundance of species seen in disks. One on-going research subject is finding new paths to synthesize species either in the gas-phase or on grain surfaces. Specific formation routes for water or carbon monoxide are discussed in more details. 13th Lecture of the Summer School "Protoplanetary Disks: Theory and Modelling Meet Observations"

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

    OpenAIRE

    Xiaoxi Yan

    2014-01-01

    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 funct...

  12. D-OPTIMAL EXPERIMENTAL DESIGNS TO TEST FOR DEPARTURE FROM ADDITIVITY IN A FIXED-RATIO RAY MIXTURE.

    Science.gov (United States)

    Risk assessors are becoming increasingly aware of the importance of assessing interactions between chemicals in a mixture. Most traditional designs for evaluating interactions are prohibitive when the number of chemicals in the mixture is large. However, evaluation of interacti...

  13. 40 CFR 721.4464 - Mixture of hydrofluoro alkanes and hydrofluoro alkene.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Mixture of hydrofluoro alkanes and... Specific Chemical Substances § 721.4464 Mixture of hydrofluoro alkanes and hydrofluoro alkene. (a) Chemical... as a mixture of hydrofluoro alkanes and hydrofluoro alkene (PMNs P-96-945/946/947/948) are subject...

  14. HUGS at CEBAF: Proceedings

    International Nuclear Information System (INIS)

    This is the proceedings of the 6th consecutive Hampton University Graduate Studies (HUGS) at the Continuous Electron Beam Accelerator Facility (CEBAF). These proceedings are composed of articles produced by graduate students. The participants were divided into smaller groups. Each group chose a lecturer's presentation to focus on and write up for these proceedings. There were some cross over students; that is there were students who participated in more am one group. In addition, there were participants who pursued topics considerably further than being confined to the scope of a given lecture; these participants contributed additional articles which can also be found here. All of the HUGS at CEBAF participants worked very hard and had a good time doing it. The students lived on the Hampton University campus and attended lecture sessions at CEBAF. The atmosphere of the river front campus of Hampton and the stimulation readily available at CEBAF made for a wonderful mix. These proceedings are divided into two sections: Section 1 contain articles that were generated by the HUGS participants from lecturers' notes and discussions among the student groups and lecturers, and Section 2 contains original work generated by the HUGS participants. Section 3 contains the contributions from the lecturers. Some of the articles were reviewed by the lecturer more closely connected to the particular subject matter. The appendices contain a list of the HUGS enrollment, lecturers, schedule, and lecture assignment

  15. FINPIE/97. Workshop proceedings

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-12-31

    This publication contains the proceedings of 1997 Finnish Workshop on Power and Industrial Electronics, held in Espoo, Finland, on 26 August, 1997. The programme consisted of technical sessions on Advanced AC Motor Control, Electric Machines and Drives, Advanced Control and Measurement, Power Electronics Systems, Modelling and Simulation, and Power Converters

  16. Conference proceedings ISES 2014

    DEFF Research Database (Denmark)

    Christensen, Janne Winther; Peerstrup Ahrendt, Line; Malmkvist, Jens

    The 10th Internatinal Equitation Science Conference is held i Denmark from August 6th - 9th 2014. This book of proceedings contaions abstracts of 35 oral and 57 poster presentations within the conference themes Equine Stress, Learning and Training as well as free papers....

  17. EMAC Proceedings, Academic Sessions

    DEFF Research Database (Denmark)

    The EMAC Proceedings contains many papers related to digital information processing and telecommunications, reflecting the importance of the telecommunications industry, but also many papers on sensor systems and control systems are included. The papers come from all over Europe, from within the...

  18. Variational Theory of Mixtures in Continuum Mechanics

    CERN Document Server

    Gouin, Henri

    2008-01-01

    In continuum mechanics, the equations of motion for mixtures are derived through the use of Hamilton's extended principle which regards the mixture as a collection of distinct continua. The internal energy is assumed to be a function of densities, entropies and successive spatial gradients of each constituent. We first write the equations of motion for each constituent of an inviscid miscible mixture of fluids without chemical reactions or diffusion. Our work leads to the equations of motion in an universal thermodynamic form in which interaction terms subject to constitutive laws, difficult to interpret physically, do not occur. For an internal energy function of densities, entropies and spatial gradients, an equation describing the barycentric motion of the constituents is obtained. The result is extended for dissipative mixtures and an equation of energy is obtained. A form of Clausius-Duhem's inequality which represents the second law of thermodynamics is deduced. In the particular case of compressible mi...

  19. Realistic environmental mixtures of micropollutants in surface, drinking, and recycled water: herbicides dominate the mixture toxicity toward algae.

    Science.gov (United States)

    Tang, Janet Y M; Escher, Beate I

    2014-06-01

    Mixture toxicity studies with herbicides have focused on a few priority components that are most likely to cause environmental impacts, and experimental mixtures were often designed as equipotent mixtures; however, real-world mixtures are made up of chemicals with different modes of toxic action at arbitrary concentration ratios. The toxicological significance of environmentally realistic mixtures has only been scarcely studied. Few studies have simultaneously compared the mixture effect of water samples with designed reference mixtures comprised of the ratios of analytically detected concentrations in toxicity tests. In the present study, the authors address the effect of herbicides and other chemicals on inhibition of photosynthesis and algal growth rate. The authors tested water samples including secondary treated wastewater effluent, recycled water, drinking water, and storm water in the combined algae assay. The detected chemicals were mixed in the concentration ratios detected, and the biological effects of the water samples were compared with the designed mixtures of individual detected chemicals to quantify the fraction of effect caused by unknown chemicals. The results showed that herbicides dominated the algal toxicity in these environmentally realistic mixtures, and the contribution by the non-herbicides was negligible. A 2-stage model, which used concentration addition within the groups of herbicides and non-herbicides followed by the model of independent action to predict the mixture effect of the two groups, could predict the experimental mixture toxicity effectively, but the concentration addition model for herbicides was robust and sufficient for complex mixtures. Therefore, the authors used the bioanalytical equivalency concept to derive effect-based trigger values for algal toxicity for monitoring water quality in recycled and surface water. All water samples tested would be compliant with the proposed trigger values associated with the

  20. Mechanics of mixtures

    CERN Document Server

    Rajagopal, KR

    1995-01-01

    This book presents a unified treatment of the mechanics of mixtures of several constituents within the context of continuum mechanics. After an introduction to the basic theory in the first few chapters, the book deals with a detailed exposition of the mechanics of a mixture of a fluid and an elastic solid, which is either isotropic or anisotropic and is capable of undergoing large deformations. Issues regarding the specification of boundary conditions for mixtures are discussed in detail and several boundary value and initial-boundary value problems are solved. The status of some special theo

  1. Concentration addition, independent action and generalized concentration addition models for mixture effect prediction of sex hormone synthesis in vitro

    DEFF Research Database (Denmark)

    Hadrup, Niels; Taxvig, Camilla; Pedersen, Mikael;

    2013-01-01

    of the concentration addition (CA), independent action (IA) and generalized concentration addition (GCA) models. First we measured effects of single chemicals and mixtures thereof on steroid synthesis in H295R cells. Then single chemical data were applied to the models; predictions of mixture effects were calculated...... and compared to the experimental mixture data. Mixture 1 contained environmental chemicals adjusted in ratio according to human exposure levels. Mixture 2 was a potency adjusted mixture containing five pesticides. Prediction of testosterone effects coincided with the experimental Mixture 1 data. In contrast...

  2. Proceedings of workshop on 'boron chemistry for neutron capture therapy'

    International Nuclear Information System (INIS)

    This volume contains the proceedings of the workshop on the chemistry of Boron Neutron Capture Therapy held on 1st of August in 1988 and on 22nd of January in 1990. In this workshop, our attention was mainly focused on the chemical reactions and chemical analyses of boron compounds used for the therapy. There is additionally shown the basic knowledge of immunology related with the neutron capture therapy. We do hope that this proceedings will contribute to the development of new boron carriers for the therapy. (J.P.N.)

  3. 2014 German refrigeration and air conditioning meeting. Proceedings

    International Nuclear Information System (INIS)

    The proceedings of the 2014 German refrigeration and air conditioning meeting contain contributions on the following topics: cryotechnology, fundamentals and materials for the refrigeration and heat pump technology, devices and components for the refrigeration and heat pump technology, applications of refrigeration technologies, air conditioning technology and heat pump applications, cryotechnology in biology and medicine, heat transfer and ventilation, guidelines and legal topics, refrigerant fluid - oil mixtures, control and surveillance, simulation and control, ambient air.

  4. Quantum interaction. Proceedings

    Energy Technology Data Exchange (ETDEWEB)

    Bruza, Peter [Queensland Univ. of Technology, Brisbane (Australia). Faculty of Science and Technology; Sofge, Donald [Navy Center for Applied Research in Artificial Intelligence, Washington, DC (United States). Naval Research Lab.; Lawless, William [Paine Coll., Augusta, GA (United States); Rijsbergen, Keith van [Glasgow Univ. (United Kingdom). Dept. of Computing Science; Klusch, Matthias (eds.) [German Research Center for Artificial Intelligence, Saarbruecken (Germany)

    2009-07-01

    This book constitutes the refereed proceedings of the Third International Symposium on Quantum Interaction, QI 2009, held in Saarbruecken, Germany, in March 2009. The 21 revised full papers presented together with the 3 position papers were carefully reviewed and selected from numerous submissions. The papers show the cross-disciplinary nature of quantum interaction covering topics such as computation, cognition, decision theory, information retrieval, information systems, social interaction, computational linguistics and finance. (orig.)

  5. Mixture for solidification of liquid radioactive wastes into stable forms

    International Nuclear Information System (INIS)

    A mixture is proposed for cementing liquid radioactive wastes into chemically stable, mechanically strong, transportable and storable forms. The mixture consists of 60-80 wt.% Portland cement, 5-15 wt.% flue silica dust and 15-25 wt.% zeolitic tuffite. (Z.S.)

  6. Chemical recognition software

    Energy Technology Data Exchange (ETDEWEB)

    Wagner, J.S.; Trahan, M.W.; Nelson, W.E.; Hargis, P.J. Jr.; Tisone, G.C.

    1994-12-01

    We have developed a capability to make real time concentration measurements of individual chemicals in a complex mixture using a multispectral laser remote sensing system. Our chemical recognition and analysis software consists of three parts: (1) a rigorous multivariate analysis package for quantitative concentration and uncertainty estimates, (2) a genetic optimizer which customizes and tailors the multivariate algorithm for a particular application, and (3) an intelligent neural net chemical filter which pre-selects from the chemical database to find the appropriate candidate chemicals for quantitative analyses by the multivariate algorithms, as well as providing a quick-look concentration estimate and consistency check. Detailed simulations using both laboratory fluorescence data and computer synthesized spectra indicate that our software can make accurate concentration estimates from complex multicomponent mixtures. even when the mixture is noisy and contaminated with unknowns.

  7. Chemical recognition software

    Energy Technology Data Exchange (ETDEWEB)

    Wagner, J.S.; Trahan, M.W.; Nelson, W.E.; Hargis, P.H. Jr.; Tisone, G.C.

    1994-06-01

    We have developed a capability to make real time concentration measurements of individual chemicals in a complex mixture using a multispectral laser remote sensing system. Our chemical recognition and analysis software consists of three parts: (1) a rigorous multivariate analysis package for quantitative concentration and uncertainty estimates, (2) a genetic optimizer which customizes and tailors the multivariate algorithm for a particular application, and (3) an intelligent neural net chemical filter which pre-selects from the chemical database to find the appropriate candidate chemicals for quantitative analyses by the multivariate algorithms, as well as providing a quick-look concentration estimate and consistency check. Detailed simulations using both laboratory fluorescence data and computer synthesized spectra indicate that our software can make accurate concentration estimates from complex multicomponent mixtures, even when the mixture is noisy and contaminated with unknowns.

  8. Possible preparation of wood-plastic materials based on unsaturated polyester resins and methyl metacrylate, by radiation and chemical methods in combination

    International Nuclear Information System (INIS)

    The preparation of wood-plastic combinations (WPC) using combined methods for curing intermediate products and final products is described. In the first step, impregnated wood was irradiated using doses of 1 to 10 kGy in the presence of chemical initiators of polymerization. Thereafter, curing of this partly cured impregnating mixture was accomplished in the wood at elevated temperatures with the aid of chemical initiators of polymerization. Impregnation mixtures based on unsaturated polyester resins and methyl methacrylate, and the wood species European Beech (Fagus silvatica) and Black Alder (Alnus glutinosa) were used. The results indicate that this method of preparing WPC allows substantially lower radiation doses to be used, i.e., doses in the range of 1 to 2.5 kGy. These doses gelatinate the impregnation mixture in the wood so that the subsequent curing by chemical polymerization initiators proceeds without the impregnation mixture flowing out of the wood, and without forming bosses and incrustations. Intermediate products and wood products needing no further finish may thus be prepared: in some cases regrinding or repolish is sufficient. The possibility of using impregnation mixtures based on various unsaturated polyester resins was investigated, and the influence on the curing process of temperature, polymerization initiator concentration, methyl methacrylate concentration, inhibitor concentration, and other factors affecting curing was evaluated. (author)

  9. Thermodynamic scheme of inhomogeneous perfect fluid mixtures

    CERN Document Server

    Zarate, R D; Zarate, Ruben D.; Quevedo, Hernando

    2004-01-01

    We analyze the compatibility between the geometrodynamics and thermodynamics of a binary mixture of perfect fluids which describe inhomogeneous cosmological models. We generalize the thermodynamic scheme of general relativity to include the chemical potential of the fluid mixture with non-vanishing entropy production. This formalism is then applied to the case of Szekeres and Stephani families of cosmological models. The compatibility conditions turn out to impose symmetry conditions on the cosmological models in such a way that only the limiting case of the Friedmann-Robertson-Walker model remains compatible. This result is an additional indication of the incompatibility between thermodynamics and relativity.

  10. Thermodynamic scheme of inhomogeneous perfect fluid mixtures

    International Nuclear Information System (INIS)

    We analyse the compatibility between the geometrodynamics and thermodynamics of a binary mixture of perfect fluids which describe inhomogeneous cosmological models. We generalize the thermodynamic scheme of general relativity to include the chemical potential of the fluid mixture with non-vanishing entropy production. This formalism is then applied to the case of Szekeres and Stephani families of cosmological models. The compatibility conditions turn out to impose symmetry conditions on the cosmological models in such a way that only the limiting case of the Friedmann-Robertson-Walker model remains compatible. This result is an additional indication of the incompatibility between thermodynamics and relativity

  11. Multilevel Mixture Kalman Filter

    Directory of Open Access Journals (Sweden)

    Xiaodong Wang

    2004-11-01

    Full Text Available The mixture Kalman filter is a general sequential Monte Carlo technique for conditional linear dynamic systems. It generates samples of some indicator variables recursively based on sequential importance sampling (SIS and integrates out the linear and Gaussian state variables conditioned on these indicators. Due to the marginalization process, the complexity of the mixture Kalman filter is quite high if the dimension of the indicator sampling space is high. In this paper, we address this difficulty by developing a new Monte Carlo sampling scheme, namely, the multilevel mixture Kalman filter. The basic idea is to make use of the multilevel or hierarchical structure of the space from which the indicator variables take values. That is, we draw samples in a multilevel fashion, beginning with sampling from the highest-level sampling space and then draw samples from the associate subspace of the newly drawn samples in a lower-level sampling space, until reaching the desired sampling space. Such a multilevel sampling scheme can be used in conjunction with the delayed estimation method, such as the delayed-sample method, resulting in delayed multilevel mixture Kalman filter. Examples in wireless communication, specifically the coherent and noncoherent 16-QAM over flat-fading channels, are provided to demonstrate the performance of the proposed multilevel mixture Kalman filter.

  12. Superionic water-ammonia mixtures

    Science.gov (United States)

    Bethkenhagen, M.; Cebulla, D.; Redmer, R.; Hamel, S.

    2014-12-01

    The interior of the Giant Planets Uranus and Neptune contains large amounts of water, ammonia and methane (referred to as planetary ices). Many observable properties of these planets, such as luminosity, gravitational moments and magnetic fields, are thought to be determined by the physical and chemical properties of matter within this ice layer. Hence, the phase diagrams, equations of state and structural properties of these materials and their respective mixtures are of great interest.Especially the phase diagrams of water and ammonia gained much attention since Cavazzoni et al. [1] proposed superionic phases for these materials, which are characterized by highly mobile hydrogen ions in a lattice of oxygen and nitrogen ions, respectively. For water, the influence of such a phase on the properties of the Giant Planets as well as on exoplanets has been discussed widely. [2,3] Nevertheless, it is an open question how the properties of such a water layer change when another compound, e.g., ammonia is introduced. Considering a 1:1 mixture, we have performed ab initio simulations based on density functional theory using the VASP code [4] heating up structures which we had found from evolutionary random structure search calculations with XtalOpt [5]. We propose possible superionic water-ammonia structures present up to several Mbar. Moreover, we investigate the equation of state and transport properties of this mixture such as diffusion coefficients in order to compare with the pure compounds. These results are essential to construct new interior models for Neptune-like planets.[1] C. Cavazzoni et al., Science 283, 44 (1999).[2] R. Redmer et al., Icarus 211, 798 (2011).[3] L. Zeng and D. Sasselov, ApJ 784, 96 (2014).[4] G. Kresse and J. Hafner, Phys. Rev. B 47, 558 (1993).[5] D. C. Lonie and E. Zurek, Comput. Phys. Commun. 182, 372 (2011).

  13. Infringement proceedings of administrative bodies

    OpenAIRE

    Šimek, Roman

    2013-01-01

    The subject of the thesis is the legal definition of the proceedings for minor offence which falls within the area of administrative punishment on the issue of pardon of the oral proceedings on the part of the accused and the tutoring of the administrative authorities. Proceedings for minor offences is governed by the administrative regulations and the law the on misdemeanors. The administrative authorities must follow the basic principles of its activities which does not stem only from these...

  14. 29 CFR 98.965 - Legal proceedings.

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 1 2010-07-01 2010-07-01 true Legal proceedings. 98.965 Section 98.965 Labor Office of the Secretary of Labor GOVERNMENTWIDE DEBARMENT AND SUSPENSION (NONPROCUREMENT) Definitions § 98.965 Legal proceedings. Legal proceedings means any criminal proceeding or any civil judicial proceeding, including...

  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. 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

  17. Proceedings of ICED'09

    DEFF Research Database (Denmark)

    The 17th International Conference on Engineering Design, ICED'09, was held August 24-27 2009 at Stanford University, California, USA. The Conference is the flagship event of the Design Society, a society dedicated to contributing to a broad and established understanding of development and design...... thinking, theory, and practice, with a premium placed on evidence-based research. The papers are published in a total of ten volumes of Proceedings, in addition to electronic publication. This volume contains 32 papers concerned with Design for X, Design to X, where X can represent a variety of attributes...

  18. Proceedings of ICI 2011

    International Nuclear Information System (INIS)

    This proceedings contains articles of ICI 2011 of the Joint conference, ISOFIC(International Symposium on Future I and C for Nuclear Power Plants), CSEPC(Cognitive Systems Engineering in Process Control), ISSNP(International Symposium on Symbiotic Nuclear Power Systems). It was held on August 21-25, 2011, Daejeon, Korea. The main topic titles of session are as follows: Advanced technologies, Modernization of control room, Software reliability of digital IEC systems, NPP control, Risk evaluation of real plants and components, Simulation methods for reactor accidents and others. (Yi, J. H.)

  19. ITER council proceedings: 1997

    International Nuclear Information System (INIS)

    This volume of the ITER EDA Documentation Series presents records of the 12th ITER Council Meeting, IC-12, which took place on 23-24 July, 1997 in Tampere, Finland. The Council received from the Parties (EU, Japan, Russia, US) positive responses on the Detailed Design Report. The Parties stated their willingness to contribute to fulfil their obligations in contributing to the ITER EDA. The summary discussions among the Parties led to the consensus that in July 1998 the ITER activities should proceed for additional three years with a general intent to enable an efficient start of possible, future ITER construction

  20. Chemical warfare in freshwater

    NARCIS (Netherlands)

    Mulderij, Gabi

    2006-01-01

    Aquatic macrophytes can excrete chemical substances into their enviroment and these compounds may inhibit the growth of phytoplankton. This process is defined as allelopathy: one organism has effects on another via the excretion of a (mixture of) chemical substance(s). With laboratory and field expe

  1. 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...

  2. Auroral Tomography Workshop, Proceedings

    International Nuclear Information System (INIS)

    In ionospheric and atmospheric physics the importance of multi-station imaging has grown as a consequence of the availability of scientific grade CCD cameras with digital output and affordable massive computing power. Tomographic inversion techniques are used in many different areas, e.g. medicine, plasma research and space physics. The tomography workshop was announced to gather a limited group of people interested in auroral tomography or tomographic inversion methods in general. ALIS (Auroral Large Imaging System) is a multi-station ground-based system developed primarily for three-dimensional auroral imaging, however other non-auroral objects can be studied with ALIS, e.g. stratospheric clouds. Several of the contributions in the workshop dealt with problems related to geometries similar to the ALIS-configuration. The Proceedings contain written contributions received either in abstract form or as full papers. The Proceedings also contain contributions intended for the Workshop but not presented due to the absence of the speaker. Separate abstracts have been prepared for 15 of the 17 papers

  3. Eighteenth symposium on biotechnology for fuels and chemicals: Program and abstracts

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-12-31

    This volume provides the proceedings for the Eighteenth Symposium on Biotechnology for Fuels and Chemicals held May 5-9, 1996 in Gatlinburg, Tennessee. The proceedings contains abstracts for oral and poster presentations.

  4. Thermal analysis of pyrotechnic mixture-fireworks, atom-bomb

    International Nuclear Information System (INIS)

    Sound level produced from two varieties of sound producing fireworks of atom-bomb, cake bomb and thunder bomb were measured. The pyrotechnic mixture, KNO3/S/Al(H3BO3) 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, KNO3/S/Al(H3BO3) 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)

  5. Interfacial tension and nucleation in mixtures of colloids and long ideal polymer coils

    OpenAIRE

    Sear, Richard P.

    2002-01-01

    Mixtures of ideal polymers with hard spheres whose diameters are smaller than the radius of gyration of the polymer, exhibit extensive immiscibility. The interfacial tension between demixed phases of these mixtures is estimated, as is the barrier to nucleation. The barrier is found to scale linearly with the radius of the polymer, causing it to become large for large polymers. Thus for large polymers nucleation is suppressed and phase separation proceeds via spinodal decomposition, as it does...

  6. Bioaccessibility assessment of patulin and ochratoxin A in cereal and fruit based baby foods using a harmonized in vitro digestion model: Contribution for the risk assessment of chemical mixtures

    OpenAIRE

    Assunção, R.; Martins, C.; Leclerc Duarte, E.; Alvito, P.

    2015-01-01

    People, animals and the environment can be exposed to multiple chemicals at once from a variety of sources, but current risk assessment is usually carried out on one chemical substance at a time. Mycotoxins are fungal natural contaminants commonly found in a variety of foods including baby foods and have been found in cereal and fruit based baby foods. In human health risk assessment, ingestion of food is considered a major route of exposure to many contaminants including mycotoxins, although...

  7. Study of atmospheric pressure chemical vapor deposition by using a double discharge system for SiOx thin-film deposition with a HMDS/Ar/He/O2 gas mixture

    International Nuclear Information System (INIS)

    SiOx thin films were deposited at atmospheric pressure by using a double discharge system composed of a remote-type dielectric barrier discharge (DBD) formed above the substrate and a direct-type DBD formed by applying an AC power to the substrate with a gas mixture of hexamethyldisilazane (HMDS)/O2/He/Ar. Instead of using a single DBD, the use of the double discharge system not only showed higher SiOx thin film deposition rates but also produced fewer impurities in the deposited SiOx thin film. The improvement was partially related to the increased gas dissociation near the substrate through the direct-type DBD and to the remote-type DBD. A 7-kV, 30-kHz AC voltage was applied to the remote-type DBD and a 5-kV, 20-kHz AC voltage was applied to the direct-type DBD, with a gas mixture of HMDS (400 sccm)/O2 (20 slm)/He (5 slm)/Ar (3 slm). As a result, a SiOx deposition rate of 58.29 nm/scan could be obtained while moving the substrate at a speed of 0.25 meter/min.

  8. Premature reproductive aging in female rats after developmental exposure to mixtures of endocrine disrupters

    DEFF Research Database (Denmark)

    Jacobsen, Pernille Rosenskjold; Petersen, Marta Axelstad; Christiansen, Sofie; Boberg, Julie; Hass, Ulla

    2013-01-01

    Long-lasting and delayed reproductive effects of developmental exposure to mixtures of environmental chemicals were investigated in female rats. Wistar rats were dosed during gestation and lactation to mixtures of endocrine disrupters, and effects in offspring were studied. The mixtures consisted...

  9. Mixed waste: Proceedings

    International Nuclear Information System (INIS)

    This volume contains the peer-reviewed and edited versions of papers submitted for presentation a the Second International Mixed Waste Symposium. Following the tradition of the First International Mixed Waste Symposium, these proceedings were prepared in advance of the meeting for distribution to participants. The symposium was organized by the Mixed Waste Committee of the American Society of Mechanical Engineers. The topics discussed at the symposium include: stabilization technologies, alternative treatment technologies, regulatory issues, vitrification technologies, characterization of wastes, thermal technologies, laboratory and analytical issues, waste storage and disposal, organic treatment technologies, waste minimization, packaging and transportation, treatment of mercury contaminated wastes and bioprocessing, and environmental restoration. Individual abstracts are catalogued separately for the data base

  10. Norddesign 2012 - Proceedings

    DEFF Research Database (Denmark)

    fate of the ideas behind the conferences. In that view the conferences have been thematically open and the organization has been tight with a limited number of participants that allows a good overview of all the papers and a lot of informal discussion between the participants. The present conference...... received more than 140 abstracts and through the review process this have resulted in approximately 70 accepted papers. One of the new research fields included in this conference is the area of Biomechanics – hence the cover graphics of the conference proceedings. With this short introduction we encourage...... you to study and reflect upon the topics and content of the accepted papers. And not at least to let this inspire you in fruitful discussions during the conference...

  11. Feedwater heater workshop proceedings

    International Nuclear Information System (INIS)

    The March 13-14, 1979 EPRI sponsored workshop on design, operation and maintenance problems with nuclear feedwater heaters identified a large number of significant technical areas of concern. The reported problems relate to nearly all facets of feedwater heater technology. In particular, hydrometallurgical problems such as stress corrosion of stainless tubing, erosion/corrosion wear of tube-tubesheet joints, and flashing related tube erosion at the entrance to the drain cooler region were reviewed in depth. Shortcomings in current design standards and design specifications were also discussed. Solutions to specific technical problems such as mechanics of flow induced vibration failures, improved synthesis of feedwater heater orientation with plant layout, and drain outlet piping design were presented. A list of important technical problems requiring additional research and development for improved design guidelines was developed. The proceedings contain all edited material of archival quality developed in this workshop

  12. Imaging Sciences Workshop Proceedings

    Energy Technology Data Exchange (ETDEWEB)

    Candy, J.V.

    1996-11-21

    This report contains the proceedings of the Imaging Sciences Workshop sponsored by C.A.S.LS., the Center for Advanced Signal & Image Sciences. The Center, established primarily to provide a forum where researchers can freely exchange ideas on the signal and image sciences in a comfortable intellectual environment, has grown over the last two years with the opening of a Reference Library (located in Building 272). The Technical Program for the 1996 Workshop include a variety of efforts in the Imaging Sciences including applications in the Microwave Imaging, highlighted by the Micro-Impulse Radar (MIR) system invented at LLNL, as well as other applications in this area. Special sessions organized by various individuals in Speech, Acoustic Ocean Imaging, Radar Ocean Imaging, Ultrasonic Imaging, and Optical Imaging discuss various applica- tions of real world problems. For the more theoretical, sessions on Imaging Algorithms and Computed Tomography were organized as well as for the more pragmatic featuring a session on Imaging Systems.

  13. Mixed waste: Proceedings

    Energy Technology Data Exchange (ETDEWEB)

    Moghissi, A.A.; Blauvelt, R.K.; Benda, G.A.; Rothermich, N.E. [eds.] [Temple Univ., Philadelphia, PA (United States). Dept. of Environmental Safety and Health

    1993-12-31

    This volume contains the peer-reviewed and edited versions of papers submitted for presentation a the Second International Mixed Waste Symposium. Following the tradition of the First International Mixed Waste Symposium, these proceedings were prepared in advance of the meeting for distribution to participants. The symposium was organized by the Mixed Waste Committee of the American Society of Mechanical Engineers. The topics discussed at the symposium include: stabilization technologies, alternative treatment technologies, regulatory issues, vitrification technologies, characterization of wastes, thermal technologies, laboratory and analytical issues, waste storage and disposal, organic treatment technologies, waste minimization, packaging and transportation, treatment of mercury contaminated wastes and bioprocessing, and environmental restoration. Individual abstracts are catalogued separately for the data base.

  14. Progress report on nuclear science and technology in China (Vol.2). Proceedings of academic annual meeting of China Nuclear Society in 2011, No.5--nuclear chemical engineering sub-volume

    International Nuclear Information System (INIS)

    Progress report on nuclear science and technology in China (Vol. 2) includes 698 articles which were presented on the second national academic annual meeting of China Nuclear Society. There are 10 books totally. This is the fifth one, the content is about nuclear chemical engineering.

  15. Análisis Químico de Mezclas Biodiesel de Aceite de Cocina Usado y Diesel por Espectroscopia Infrarroja Chemical Analysis of Mixtures of Biodiesel from Used Cooking Oil and Diesel by Infrared Spectroscopy

    Directory of Open Access Journals (Sweden)

    Jennifer J Lafont

    2011-01-01

    Full Text Available Se propone un método eficiente para determinar los porcentajes óptimos de mezclas biodiesel de aceite usado y diesel, para uso automotor. El procedimiento consiste en recolección del aceite usado, limpieza de residuos, y obtención del biodiesel mediante una reacción de transesterificación, con diferentes proporciones molares metanol/aceite . Las muestras fueron analizadas por espectroscopia infrarroja. Se encontró que una proporción metanol/aceite de 1:8 presentó mayor rendimiento en la obtención de biodiesel. Los espectros de infrarrojo mostraron el incremento del máximo de carbonilo de los esteres metílicos al aumentar las concentraciones de biodiesel en las mezcla biodiesel+diesel. Se concluye que la técnica usada cumple con la ley de Beer-Lambert y es adecuada para cuantificar este tipo de mezclas.An efficient method to determine the optimum percentages of blends biodiesel from used oil and diesel for automotive use, is proposed. The procedure consists of recollection of used frying oil, residue cleaning and synthesis of biodiesel by a transesterification reaction with different molar proportions of methanol/oil. The samples were analyzed by infrared spectroscopy. It was found that a ratio methanol/oil of 1:8 showed higher performance in the production of biodiesel. The infrared spectra showed an increase in the carbonyl peak of the methyl esters with the increase of the concentration of biodiesel in the mixtures biodiesel+diesel. It is concluded that proposed technique complies with the Beer-Lambert law and it is a good method to quantify these types of mixtures.

  16. SIMS applications workshop. Proceedings

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-04-01

    The first ANSTO/AINSE SIMS Workshop drew together a mixture of Surface Analysis experts and Surface Analysis users with the concept that SIMS analysis has to be enfolded within the spectrum of surface analysis techniques and that the user should select the technique most applicable to the problem. With this concept in mind the program was structured as sessions on SIMS Facilities; Applications to Mineral Surfaces; Applications to Biological Systems, Applications to Surfaces as Semi- conductors, Catalysts and Surface Coatings; and Applications to Ceramics

  17. SIMS applications workshop. Proceedings

    International Nuclear Information System (INIS)

    The first ANSTO/AINSE SIMS Workshop drew together a mixture of Surface Analysis experts and Surface Analysis users with the concept that SIMS analysis has to be enfolded within the spectrum of surface analysis techniques and that the user should select the technique most applicable to the problem. With this concept in mind the program was structured as sessions on SIMS Facilities; Applications to Mineral Surfaces; Applications to Biological Systems, Applications to Surfaces as Semi- conductors, Catalysts and Surface Coatings; and Applications to Ceramics

  18. Proceedings of the 24. Arctic and Marine Oilspill Program (AMOP) Technical Seminar, including the 18. Technical Seminar on Chemical Spills (TSOCS) and the 3. Phytoremediation/Biotechnology Solutions for Spills (PHYTO)

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2001-07-01

    The 59 papers presented at this conference discussed the latest technologies regarding marine oil spills. The conference was divided into 11 sessions entitled: (1) physical and chemical properties, (2) contingency planning and activity updates, (3) biological effects, biodegradation and PHYTO, (4) containment and recovery, (5) Louisiana special session, (6) detection, tracking and remote sensing, (7) oil spill treating agents, (8) spill modelling, (9) shoreline protection and cleanup, (10) in-situ burning, and (11) technical seminar on chemical spills. A poster session was also included. The major objective of this conference was to help emergency response personnel better understand the process of oil in water interactions. In addition, the conference was aimed at optimizing response functions such as oil spill notification, situation analysis, strategy development for marine oil spill response, site safety, equipment deployment, containment, recovery, shoreline assessment, cleanup, communications, and decontamination of polluted waters. All 59 papers were processed separately for inclusion in the database. refs., tabs., figs.

  19. Late-life effects on rat reproductive system after developmental exposure to mixtures of endocrine disrupters

    DEFF Research Database (Denmark)

    Isling, Louise Krag; Boberg, Julie; Jacobsen, Pernille Rosenskjold;

    2014-01-01

    This study examined late-life effects of perinatal exposure of rats to a mixture of endocrine-disrupting contaminants. Four groups of 14 time-mated Wistar rats were exposed by gavage from gestation day 7 to pup day 22 to a mixture of 13 anti-androgenic and estrogenic chemicals including phthalates......, pesticides, u.v.-filters, bisphenol A, parabens, and the drug paracetamol. The groups received vehicle (control), a mixture of all 13 chemicals at 150-times (TotalMix150) or 450-times (TotalMix450) high-end human exposure, or 450-times a mixture of nine predominantly anti-androgenic chemicals (AAMix450...

  20. Simulations of chemical catalysis

    Science.gov (United States)

    Smith, Gregory K.

    This dissertation contains simulations of chemical catalysis in both biological and heterogeneous contexts. A mixture of classical, quantum, and hybrid techniques are applied to explore the energy profiles and compare possible chemical mechanisms both within the context of human and bacterial enzymes, as well as exploring surface reactions on a metal catalyst. A brief summary of each project follows. Project 1 - Bacterial Enzyme SpvC The newly discovered SpvC effector protein from Salmonella typhimurium interferes with the host immune response by dephosphorylating mitogen-activated protein kinases (MAPKs) with a beta-elimination mechanism. The dynamics of the enzyme substrate complex of the SpvC effector is investigated with a 3.2 ns molecular dynamics simulation, which reveals that the phosphorylated peptide substrate is tightly held in the active site by a hydrogen bond network and the lysine general base is positioned for the abstraction of the alpha hydrogen. The catalysis is further modeled with density functional theory (DFT) in a truncated active-site model at the B3LYP/6-31 G(d,p) level of theory. The truncated model suggested the reaction proceeds via a single transition state. After including the enzyme environment in ab initio QM/MM studies, it was found to proceed via an E1cB-like pathway, in which the carbanion intermediate is stabilized by an enzyme oxyanion hole provided by Lys104 and Tyr158 of SpvC. Project 2 - Human Enzyme CDK2 Phosphorylation reactions catalyzed by kinases and phosphatases play an indispensable role in cellular signaling, and their malfunctioning is implicated in many diseases. Ab initio quantum mechanical/molecular mechanical studies are reported for the phosphoryl transfer reaction catalyzed by a cyclin-dependent kinase, CDK2. Our results suggest that an active-site Asp residue, rather than ATP as previously proposed, serves as the general base to activate the Ser nucleophile. The corresponding transition state features a

  1. 2 CFR 180.965 - Legal proceedings.

    Science.gov (United States)

    2010-01-01

    ... 2 Grants and Agreements 1 2010-01-01 2010-01-01 false Legal proceedings. 180.965 Section 180.965 Grants and Agreements OFFICE OF MANAGEMENT AND BUDGET GOVERNMENTWIDE GUIDANCE FOR GRANTS AND AGREEMENTS... § 180.965 Legal proceedings. Legal proceedings means any criminal proceeding or any civil...

  2. 7 CFR 3017.965 - Legal proceedings.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 15 2010-01-01 2010-01-01 false Legal proceedings. 3017.965 Section 3017.965 Agriculture Regulations of the Department of Agriculture (Continued) OFFICE OF THE CHIEF FINANCIAL OFFICER... Legal proceedings. Legal proceedings means any criminal proceeding or any civil judicial...

  3. 21 CFR 1404.965 - Legal proceedings.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 9 2010-04-01 2010-04-01 false Legal proceedings. 1404.965 Section 1404.965 Food and Drugs OFFICE OF NATIONAL DRUG CONTROL POLICY GOVERNMENTWIDE DEBARMENT AND SUSPENSION (NONPROCUREMENT) Definitions § 1404.965 Legal proceedings. Legal proceedings means any criminal proceeding or...

  4. 7 CFR 97.201 - Protest proceedings.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 3 2010-01-01 2010-01-01 false Protest proceedings. 97.201 Section 97.201 Agriculture... PLANT VARIETY AND PROTECTION Protest Proceedings § 97.201 Protest proceedings. (a) Opposition shall be made by submitting in writing a petition for protest proceedings, which petition shall be supported...

  5. Chemical reaction and separation method

    NARCIS (Netherlands)

    Jansen, J.C.; Kapteijn, F.; Strous, S.A.

    2005-01-01

    The invention is directed to process for performing a chemical reaction in a reaction mixture, which reaction produces water as by-product, wherein the reaction mixture is in contact with a hydroxy sodalite membrane, through which water produced during the reaction is removed from the reaction mixtu

  6. ECMDA Traceability Workshop Proceedings 2007

    OpenAIRE

    Oldevik, Jon; Olsen, Gøran Klepp; Neple, Tor

    2007-01-01

    This report contains the proceedings of the Third ECMDA Traceability Workshop, arrangedin Haifa, Israel 2007 together with ECMDA 2007 conference. The papers within targetvarious aspects of traceability in model-driven development.  Oppdragsgiver: ECMDA Traceability Workshop

  7. Theory of elementary particles. Proceedings

    International Nuclear Information System (INIS)

    These proceedings contain most of the invited talks ans short communications presented at the named symposium. These concern developments in field theory in connection with string models, grand unification, and quantum gravity. See hints under the relevant topics. (HSI)

  8. Bioavailability of genotoxic mixtures in soil

    Energy Technology Data Exchange (ETDEWEB)

    Bordelon, N.; Washburn, K.; He, L.Y.; Donnelly, K.C. [Texas A and M Univ., College Station, TX (United States). Dept. of Veterinary Anatomy and Public Health

    1996-12-31

    Contaminated media at Superfund sites typically consist of complex mixtures of organic and inorganic chemicals which are difficult to characterize, both analytically and toxicologically. The current EPA approach to risk assessment uses solvent extraction to remove chemicals from the soil as a basis for estimating risk to the human population. However, contaminants that can be recovered with a solvent extract may not represent the mixture of chemicals that are available for human exposure. A procedure using an aqueous extraction was investigated to provide a more realistic estimate of what chemicals are bioavailable. A study was conducted with two soil types: creosote-contaminated sandy soil and coal tar-contaminated clay soil spiked with benzo(a)pyrene [B(a)P], and trinitrotoluene (TNT). Samples were extracted with hexane:acetone and water titrated to pH2 and pH7. HPLC analysis demonstrated up to 35% and 29% recovery of contaminants using the aqueous extracts. The estimated cancer risk for the aqueous extract was one order of magnitude less than that for solvent extracts. Analysis using the Salmonella/microsome assay demonstrated that solvent extracts were genotoxic (133 revertants/mg) with metabolic activation while aqueous extracts of clay soil were not genotoxic. Sandy soil showed genotoxicity both with and without metabolic activation. These results suggest that solvent extraction techniques may overestimate the concentration of contaminants that are available for human exposure and, hence, the risk associated with the presence of the contaminants in soil.

  9. NIC symposium 2010. Proceedings

    International Nuclear Information System (INIS)

    The fifth NIC-Symposium gave an overview of the activities of the John von Neumann Institute for Computing (NIC) and of the results obtained in the last two years by research groups supported by the NIC. The large recent progress in supercomputing is highlighted by the fact that the newly installed Blue Gene/P system in Juelich - with a peak performance of 1 Petaflop/s - currently ranks number four in the TOP500 list. This development opens new dimensions in simulation science for researchers in Germany and Europe. NIC - a joint foundation of Forschungszentrum Juelich, Deutsches Elektronen-Synchrotron (DESY) and Gesellschaft fuer Schwerionenforschung (GSI) - supports with its members' supercomputer facilities about 130 research groups at universities and national labs working on computer simulations in various fields of science. Fifteen invited lectures covered selected topics in the following fields: Astrophysics Biophysics Chemistry Elementary Particle Physics Condensed Matter Materials Science Soft Matter Science Environmental Research Hydrodynamics and turbulence Plasma Physics Computer Science The talks are intended to inform a broad audience of scientists and the interested public about the research activities at NIC. The proceedings of the symposium cover projects that have been supported by the IBM supercomputers JUMP and IBM Blue Gene/P in Juelich and the APE topical computer at DESY-Zeuthen in an even wider range than the lectures.

  10. LHC Nobel Symposium Proceedings

    Science.gov (United States)

    Ekelöf, Tord

    2013-12-01

    puzzlement. The apparent absence of hints in the LHC experimental data of new phenomena that could relate to dark matter, dark energy, the dominance of matter over antimatter in the Universe, the unification of the strong and the electroweak interactions and their further unification with gravity left the Symposium with no guidance as to how to answer the question: what next? And in experimental fundamental science it is not the confirmation of already established theories that thrills the most; it is the appearance of the unexpected that creates the greatest excitement. However, the LHC is only at the beginning of its voyage into the uncharted territories of higher energies and smaller dimensions that it was built for, so the possibilities for unexpected discoveries are only starting to be explored. The LHC will start up again in 2015 with nearly twice its previous energy and with increased luminosity—new discoveries might then appear sooner than we even dare hope for! The LHC Nobel Symposium was attended by about 60 invited participants and lasted four days. The program was divided into seven sessions; QCD and Heavy Ion Physics, B Physics, Electroweak Physics, The Higgs Boson, Connections to Neutrino Physics and Astroparticle Physics, Beyond the Standard Model and Forward Look. There were 27 plenary invited talks given by participants, each followed by lively discussions. All but one of the speakers have submitted write-ups of their talks for these proceedings. We are hopeful that the remaining talk will be published in a forthcoming issue of Physica Scripta . I am gratified that Professor Roland Allen has agreed to write a paper on the essence of the Higgs boson discovery to be published in Physica Scripta , intended for undergraduate students and educated physicists, regardless of their field of research. I wish to express my deep gratitude to all Speakers and Participants in the Symposium, to the Members of the Local and International Organizing Committees, to the

  11. NIC symposium 2010. Proceedings

    Energy Technology Data Exchange (ETDEWEB)

    Muenster, Gernot [Muenster Univ. (Germany). Inst. fuer Theoretische Physik 1; Wolf, Dietrich [Duisburg-Essen Univ., Duisburg (Germany). Fakultaet fuer Physik; Kremer, Manfred (eds.) [Forschungszentrum Juelich GmbH (DE). Juelich Supercomputing Centre (JSC)

    2012-06-21

    The fifth NIC-Symposium gave an overview of the activities of the John von Neumann Institute for Computing (NIC) and of the results obtained in the last two years by research groups supported by the NIC. The large recent progress in supercomputing is highlighted by the fact that the newly installed Blue Gene/P system in Juelich - with a peak performance of 1 Petaflop/s - currently ranks number four in the TOP500 list. This development opens new dimensions in simulation science for researchers in Germany and Europe. NIC - a joint foundation of Forschungszentrum Juelich, Deutsches Elektronen-Synchrotron (DESY) and Gesellschaft fuer Schwerionenforschung (GSI) - supports with its members' supercomputer facilities about 130 research groups at universities and national labs working on computer simulations in various fields of science. Fifteen invited lectures covered selected topics in the following fields: Astrophysics Biophysics Chemistry Elementary Particle Physics Condensed Matter Materials Science Soft Matter Science Environmental Research Hydrodynamics and turbulence Plasma Physics Computer Science The talks are intended to inform a broad audience of scientists and the interested public about the research activities at NIC. The proceedings of the symposium cover projects that have been supported by the IBM supercomputers JUMP and IBM Blue Gene/P in Juelich and the APE topical computer at DESY-Zeuthen in an even wider range than the lectures.

  12. Combustion of soybean oil and diesel mixtures for heating purposes

    Energy Technology Data Exchange (ETDEWEB)

    Guimaraes, Adriana Correa; Sanz, Jose Francisco [European University Miguel de Cervantes, Valladolid (Spain)], E-mail: acorrea@uemc.es; Hernandez, Salvador; Navas, Luis Manuel; Rodriguez, Elena; Ruiz, Gonzalo [University of Valladolid (Spain). Dept. of Agricultural and Forest Engineering; San Jose, Julio [University of Valladolid (Spain). Dept. of Energetic Engineering; Gomez, Jaime [University of Valladolid (Spain). Dept. of Communications and Signal Theory and Telematics Engineering

    2008-07-01

    Using blends of vegetable oils with petroleum derivates for heating purposes has several advantages over other energy application for vegetable oils. This paper presents the results of an investigation by use of soybean oil and diesel mixture as fuel for producing heat in conventional diesel installation. The paper is set out as follows: properties characterization of soybean oil as fuel and of diesel oil, as well as the mixture of both; selection of the mixture according to their physical chemical properties and how they adapt to conventional combustion installation; experimentation with the selected mixture, allowing the main combustion parameters to be measured; processing the collected data, values of combustion, efficiency and reduction of emissions. Conclusions show that the use of soybean oil and diesel mixture for producing heat energy in conventional equipment is feasible and beneficial for reduction emissions. (author)

  13. A structural investigation of ionic liquid mixtures.

    Science.gov (United States)

    Matthews, Richard P; Villar-Garcia, Ignacio J; Weber, Cameron C; Griffith, Jeraime; Cameron, Fiona; Hallett, Jason P; Hunt, Patricia A; Welton, Tom

    2016-03-16

    The structures of mixtures of ionic liquids (ILs) featuring a common 1-butyl-3-methylimidazolium ([C4C1im](+)) cation but different anions have been investigated both experimentally and computationally. (1)H and (13)C NMR of the ILs and their mixtures has been performed both on the undiluted liquids and those diluted by CD2Cl2. These experiments have been complemented by quantum chemical density functional theory calculations and molecular dynamics simulations. These techniques have identified the formation of preferential interactions between H(2) of the imidazolium cation and the most strongly hydrogen bond (H-bond) accepting anion. In addition, a preference for the more weakly H-bond accepting anion to interact above the imidazolium ring through anion-π(+) interactions has been identified. The modelling of these data has identified that the magnitude of these preferences are small, of the order of only a few kJ mol(-1), for all IL mixtures. No clustering of the anions around a specific cation could be observed, indicating that these interactions arise from the reorientation of the cation within a randomly assigned network of anions. π(+)-π(+) stacking of the imidazolium cations was also studied and found to be promoted by ILs with a strong H-bond accepting anion. Stacking interactions are easily disrupted by the introduction of small proportions (accounting for why most IL mixtures exhibit ideal, or nearly ideal, behaviour. PMID:26947103

  14. Mixture Based Outlier Filtration

    Directory of Open Access Journals (Sweden)

    P. Pecherková

    2006-01-01

    Full Text Available Success/failure of adaptive control algorithms – especially those designed using the Linear Quadratic Gaussian criterion – depends on the quality of the process data used for model identification. One of the most harmful types of process data corruptions are outliers, i.e. ‘wrong data’ lying far away from the range of real data. The presence of outliers in the data negatively affects an estimation of the dynamics of the system. This effect is magnified when the outliers are grouped into blocks. In this paper, we propose an algorithm for outlier detection and removal. It is based on modelling the corrupted data by a two-component probabilistic mixture. The first component of the mixture models uncorrupted process data, while the second models outliers. When the outlier component is detected to be active, a prediction from the uncorrupted data component is computed and used as a reconstruction of the observed data. The resulting reconstruction filter is compared to standard methods on simulated and real data. The filter exhibits excellent properties, especially in the case of blocks of outliers. 

  15. Separation of gas mixtures

    International Nuclear Information System (INIS)

    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)

  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. Proceedings of transuranium elements

    International Nuclear Information System (INIS)

    The identification of the first synthetic elements was established by chemical evidence. Conclusive proof of the synthesis of the first artificial element, technetium, was published in 1937 by Perrier and Segre. An essential aspect of their achievement was the prediction of the chemical properties of element 43, which had been missing from the periodic table and which was expected to have properties similar to those of manganese and rhenium. The discovery of other artificial elements, astatine and francium, was facilitated in 1939-1940 by the prediction of their chemical properties. A little more than 50 years ago, in the spring of 1940, Edwin McMillan and Philip Abelson synthesized element 93, neptunium, and confirmed its uniqueness by chemical means. On August 30, 1940, Glenn Seaborg, Arthur Wahl, and the late Joseph Kennedy began their neutron irradiations of uranium nitrate hexahydrate. A few months later they synthesized element 94, later named plutonium, by observing the alpha particles emitted from uranium oxide targets that had been bombarded with deuterons. Shortly thereafter they proved that is was the second transuranium element by establishing its unique oxidation-reduction behavior. The symposium honored the scientists and engineers whose vision and dedication led to the discovery of the transuranium elements and to the understanding of the influence of 5f electrons on their electronic structure and bonding. This volume represents a record of papers presented at the symposium

  18. Village Power `97. Proceedings

    Energy Technology Data Exchange (ETDEWEB)

    Cardinal, J.; Flowers, L.; Taylor, R.; Weingart, J. [eds.

    1997-09-01

    It is estimated that two billion people live without electricity and its services. In addition, there is a sizable number of rural villages that have limited electrical service, with either part-day operation by diesel gen-sets or partial electrification (local school or community center and several nearby houses). For many villages connected to the grid, power is often sporadically available and of poor quality. The U.S. National Renewable Energy Laboratory (NREL) in Golden, Colorado, has initiated a program to address these potential electricity opportunities in rural villages through the application of renewable energy (RE) technologies. The objective of this program is to develop and implement applications that demonstrate the technical performance, economic competitiveness, operational viability, and environmental benefits of renewable rural electric solutions, compared to the conventional options of line extension and isolated diesel mini-grids. These four attributes foster sustainability; therefore, the program is entitled Renewables for Sustainable Village Power (RSVP). The RSVP program is a multi-disciplinary, multi-technology, multi-application program composed of six key activities, including village application development, computer model development, systems analysis, pilot project development, technical assistance, and an Internet-based village power project database. The current program emphasizes wind, photovoltaics (PV), and their hybrids with diesel gen-sets. NREL`s RSVP team is currently involved in rural electricity projects in thirteen countries, with U.S., foreign, and internationally based agencies and institutions. This document contains reports presented at the Proceedings of Village Power, 1997. Individual projects have been processed separately for the United States Department of Energy databases.

  19. Estudo químico e granulométrico das misturas de fosforita de olinda e apatita do araxá com superfosfato simples Chemical and mechanical study of fosforita de olinda and apatita do araxa mixtures (rock phosphates with ordinary superphosphate

    Directory of Open Access Journals (Sweden)

    Francisco da Costa Verdade

    1960-01-01

    Full Text Available Misturas de superfosfato simples, com apatita do Araxá e com fosforita de Olinda, foram estudadas em função do tempo de contato dos componentes e dos teores de P2O5, solúvel em água, ácido cítrico a 2% (Wagner e citrato de amônro. O efeito da moagem, na porcentagem de P2O5 solúvel na água e os índices de pH resultantes das misturas, foram também analisados, bem como a granulometria do material e as variações do seu teor de umidade. Verificou-se que a fosforita de Olinda causa uma insolubilizaçao do P2O5 solúvel em água do superfosfato, quando este adubo participa das misturas nas menores proporções, e que este fenômeno se estabiliza aos 135 dias de contato dos componentes. Aumentando a porcentagem de superfosfato nas misturas, em linhas gerais o fenômeno se desenvolveu de maneira idêntica, não obstante tenha sido verificado aumento de solu-bilidade nas dosagens iniciais. Em todas as misturas com apatita do Araxá, o teor de P(20(5 solúvel em água mostrou-se inicialmente igual ou superior ao teor teórico que deveriam apresentar as misturas, se não ocorresse interação entre seus componentes. Aumentando, porém, o tempo de contato, verificou-se retrogradação crescente desta fração solúvel, sem evidência de estabilização do processo dentro do período de controle da experiência. De um modo geral, o teor de fósforo extraído pelo ácido cítrico, menos a fração solúvel em água das misturas, com ambos os fosfatos naturais cresce com o tempo de contato, inversamente ao que acontece com o P20(5 solúvel em água. A solubilidade das misturas com fosforita em citrato de amônio também aumentou em função do tempo de contato dos componentes, parecendo atingir o ponto de equilíbrio aos 135 dias. Com as misturas de apatita os resultados se mostraram erráticos.Mixtures of ordinary superphosphate with fosforita tie Olinda (sedimentary origin and apatita do Araxá (apatite type were studied by chemical and

  20. On Theories for Reacting Immiscible Mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Drumheller, D.S.

    1998-11-05

    On some small scale each constituent of an immiscible mixture occupies a separate region of space. Given sufficient time and computing power, we could solve the continuum field equations and boundary conditions for this het erogenous system. This usually represents an enormously difficult task that is well beyond today's computational ca- pabilities. Mixture theories approximate this complex heterogeneous formulation with a set of field equations for an equivalent homoge- neous mat erial. In this work, we compare the theory for immiscible mixtures by Drumheller and Bedford with the theory of Passman, Nunziato, and Walsh. We describe the conditions under which these theories reduce to an equivalent formulation, and we also investigate the differences in their microinertial descriptions. Two variables play special roles in both theories. They are t he true material density and the volume fraction. Here we use a kinematical approach based on two new variables-t he true deformation gradient and the distention gradient. We show how the true deformation gra- dient is connected to the true material density and, in the absence of chemical reactions, the volume fraction is the inverse of the deter- minant of the distention gradient. However, when chemical reactions occur, the distention gradient and the volume fraction are not directly connected. We ako present a mixture model for a granuIar expIosive. This model is based upon the work of Baer and Nunziato, but our theory differs from their work in that we Present a three-dimension-al rnodd, `.. ` - - we cast the constitutive postulates in terms of the distention gradient rather than the volume fraction, and we incorporate elastic-plastic effects into the constitutive description of the solid granules.

  1. Incompressible ionized fluid mixtures

    Czech Academy of Sciences Publication Activity Database

    Roubíček, Tomáš

    2006-01-01

    Roč. 17, č. 7 (2006), s. 493-509. ISSN 0935-1175 Institutional research plan: CEZ:AV0Z10750506 Keywords : chemically reacting fluids * Navier - Stokes * Nernst-Planck * Possion equation s * heat equation s Subject RIV: BA - General Mathematics Impact factor: 0.954, year: 2006

  2. 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.

  3. Lunar Science Conference, 5th, Houston, Tex., March 18-22, 1974, Proceedings. Volume 1 - Mineralogy and petrology. Volume 2 Chemical and isotope analyses. Organic chemistry. Volume 3 - Physical properties

    Science.gov (United States)

    Gose, W. A.

    1974-01-01

    Numerous studies on the properties of the moon based on Apollo findings and samples are presented. Topics treated include ages of the lunar nearside light plains and maria, orange material in the Sulpicius Gallus formation at the southwestern edge of Mare Serenitatis, impact-induced fractionation in the lunar highlands, igneous rocks from Apollo 16 rake samples, experimental liquid line of descent and liquid immiscibility for basalt 70017, ion microprobe mass analysis of plagioclase from 'non-mare' lunar samples, grain size and the evolution of lunar soils, chemical composition of rocks and soils at Taurus-Littrow, the geochemical evolution of the moon, U-Th-Pb systematics of some Apollo 17 lunar samples and implications for a lunar basin excavation chronology, volatile-element systematics and green glass in Apollo 15 lunar soils, solar wind nitrogen and indigenous nitrogen in Apollo 17 lunar samples, lunar trapped xenon, solar flare and lunar surface process characterization at the Apollo 17 site, and the permanent and induced magnetic dipole moment of the moon. Individual items are announced in this issue.

  4. Chemical warfare in freshwater

    OpenAIRE

    Mulderij, Gabi

    2006-01-01

    Aquatic macrophytes can excrete chemical substances into their enviroment and these compounds may inhibit the growth of phytoplankton. This process is defined as allelopathy: one organism has effects on another via the excretion of a (mixture of) chemical substance(s). With laboratory and field experiments we studied the allelopathic effects of the aquatic macrophytes, Chara and Stratiotes. Laboratory experiments showed that the aquatic macrophytes had allelopathic effects. Phytoplankton grow...

  5. Caracterização químico-nutricional de um isolado protéico de soro de leite, um hidrolisado de colágeno bovino e misturas dos dois produtos Chemical-nutritional characterization of a whey protein isolate, a bovine collagen hydrolysate and mixtures of the two products

    Directory of Open Access Journals (Sweden)

    Fabiane La Flor Ziegler

    2009-02-01

    Full Text Available OBJETIVO:Estudar química e nutricionalmente um isolado protéico de soro de leite bovino, um hidrolisado de colágeno bovino e misturas dos dois produtos visando elevado valor nutritivo e funcional. MÉTODOS: Realizaram-se análises da composição centesimal e do perfil de aminoácidos dos dois materiais protéicos, para cálculo da melhor adequação dos aminoácidos essenciais, com base no perfil recomendado pela Organização Mundial de Saúde. Os índices de valor nutritivo para o isolado de soro de leite, o hidrolisado de colágeno e as misturas foram determinados em ratos, a partir de ensaios de crescimento e de balanço de nitrogênio. Os resultados dos parâmetros nutricionais foram submetidos à análise de variância e ao teste de Tukey para a verificação de diferenças entre médias (pOBJECTIVE:The objective was the chemical and nutritional study of a bovine whey protein isolate, a bovine collagen hydrolysate and mixtures of the two products aiming at high nutritional and functional value. METHODS: Centesimal composition and amino acid analyses were performed on both proteinaceous materials for the calculation of an adequate amino acid profile based on the Food and Agriculture Organization/World Health Organization recommendation. The nutritive value indexes for the whey protein isolate, the collagen hydrolysate and mixtures of both proteins were determined in rats through growth assay and nitrogen balance. The experimental parameters from nutritional assays were submitted to analysis of variance and the Tukey test applied for differences among means (p<0.05. RESULTS: The whey protein isolate met all the requirements of the Food and Agriculture Organization/World Health Organization reference for essential amino acids while the collagen hydrolysate showed deficiency in all essential amino acids and complete absence of tryptophan. The casein showed higher efficiency than the whey isolate and mixtures of both proteins in promoting

  6. Proceedings of the 11. conference of Czech and Slovak physicists

    International Nuclear Information System (INIS)

    Out of 146 papers presented at the conference, the proceedings contain full texts of 10 papers and 17 short communications. All these contributions have been inputted to INIS. The topics covered by the conference are subnuclear physics, nuclear physics, plasma physics, detectors, physics of metals, low-temperature physics, physics of superconductors and dielectrics, optics and quantum electronics, magnetism, thin layers, chemical physics and biophysics, acoustics and physics of molecular and macromolecular systems. (Z.S.)

  7. ISMB Conference Proceedings

    Energy Technology Data Exchange (ETDEWEB)

    Teresa, Gaasterand [UCSD; Martin, Vingron

    2011-07-01

    This special issue comprises the papers accepted for presentation at the 19th Annual International Conference on Intelligent Systems for Molecular Biology, joint with the 10th European Conference on Computational Biology, an official conference of the International Society for Computational Biology (ISCB; http://www.iscb.org). ISMB/ECCB 2011 (http://www.iscb.org/ismb2011/) will take place in Vienna, Austria, from July 17 through July 19, 2011; preceded during July 14–16 by eight 1- or 2- day Special Interest Group (SIG) meetings, three satellite meetings and nine half-day tutorials; and followed by two additional satellite meetings. The 48 papers in this volume were selected from 258 submitted papers. Submitted papers were assigned to 13 areas. Area Chairs led each topic area by selecting their area's program committee and overseeing the reviewing process. Many Area Chairs were new compared to 2010, and two completely new areas were added in 2011, ‘Data Visualization’ and ‘Mass Spectrometry and Proteomics’. Six papers for which Area Chairs were in conflict were reviewed under a ‘Conflicts Management’ section headed by the Proceedings Chairs; one such paper was accepted in ‘Bioimaging’. Areas, co-chairs and acceptance information are listed in Table 1. Compared to prior years, five mature topic areas had steady submissions, ‘Evolution and Comparative Genomics’, ‘Gene Regulation and Transcriptomics’, ‘Protein Structure and Function’, ‘Sequence Analysis’, ‘Text Mining’. Two areas newer to ISMB were underrepresented this year, ‘Bioimaging’ and ‘Disease Models and Epidemiology’. One area doubled, ‘Applied Bioinformatics’, renamed from last year's ‘Other Bioinformatics Applications’; and one tripled, ‘Protein Interactions and Molecular Networks’. Across the areas, 326 members of the bioinformatics community provided reviews. Most papers received three reviews and several received four or more. There was

  8. Spectrometric mixture analysis: An unexpected wrinkle

    Indian Academy of Sciences (India)

    Robert De Levie

    2009-09-01

    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 may need an unexpectedly high precision to yield accurate answers, because of an artifact of inverse cancellation, in which a small noise or drift signal is misinterpreted in terms of a concentration difference. The computed sum of the concentrations is not affected.

  9. Fundamental combustion characteristics of lean hydrogen mixtures; Suiso kihaku kongoki no kisoteki nensho tokusei

    Energy Technology Data Exchange (ETDEWEB)

    Barat, D.; Kido, H.; Nakahara, M.; Hashimoto, J. [Kyushu University, Fukuoka (Japan)

    1997-10-01

    One of the excellent combustion characteristics of hydrogen-air mixture is that its emission is free of CO2, but the problem of NOx remains, mainly caused by the high combustion temperature. Using leaner mixture and carrying out EGR are supposed to be effective methods to reduce NOx. In this study, to examine the effectiveness of the two methods, fundamental combustion characteristics of nitrogen added lean hydrogen mixtures were investigated by chemical equilibrium calculations and measurements of turbulent combustion characteristics. It is suggested that nitrogen added mixtures can achieve lower NOx combustion than lean mixtures, taking the combustion efficiency into consideration. 7 refs., 7 figs., 1 tab.

  10. Evaporating Drops of Alkane Mixtures

    CERN Document Server

    Gu'ena, G; Poulard, C; Cazabat, Anne-Marie; Gu\\'{e}na, Geoffroy; Poulard, Christophe

    2005-01-01

    Alkane mixtures are model systems where the influence of surface tension gradients during the spreading and the evaporation of wetting drops can be easily studied. The surface tension gradients are mainly induced by concentration gradients, mass diffusion being a stabilising process. Depending on the relative concentration of the mixture, a rich pattern of behaviours is obtained.

  11. 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 and...

  12. 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.

  13. 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.

  14. Determinação das composições físico-químicas de cachaças do sul de minas gerais e de suas misturas Determination of the physical-chemical composition of homemade cachaças produced in the South of Minas Gerais and their mixtures

    Directory of Open Access Journals (Sweden)

    Fernando José Vilela

    2007-08-01

    Full Text Available Este trabalho teve por objetivo a determinação da composição físico-química de cachaças artesanais produzidas no sul do Estado de Minas Gerais e suas misturas. Foram analisados os teores de etanol, acidez volátil, aldeídos, cobre, ésteres, álcoois superiores totais e metanol, além dos álcoois propanol-1, isobutanol e 3-metil-butanol-1. Os resultados apresentam o perfil peculiar desta bebida, que apresentou teores satisfatórios de álcoois superiores, ésteres e aldeídos. O teor de cobre apresenta-se como preocupante já que algumas amostras excederam o limite de 5 mg.L-1. A produção de misturas foi estudada e esta apresenta-se como uma alternativa viável ao produtor e cooperativas.The present study sought the physical-chemical composition of homemade cachaças produced in the south of the state Minas Gerais and of mixtures of the same cachaça samples. The ethanol, aldehyde, copper, higher alcohol, volatile acid and methanol concentrations were determined, in addition to the individual propanol, 2-methyl-1-propanol and 3-methyl-1-butanol concentrations. The results demonstrated the characteristic profile of this beverage, which presented satisfactory concentrations of higher alcohols, esters, and aldehydes. The copper concentrations of some samples exceeded the limit of 5 mg. L-1. The mixtures produced from some of the cachaça samples presented a viable alternative for the producers and cooperatives because the concentrations of the components were more adequate for exportation.

  15. Fine Particle Scrubbing: A Proceedings

    Science.gov (United States)

    Journal of the Air Pollution Control Association, 1974

    1974-01-01

    These articles deal with the proceedings of a 1974 symposium on the use of wet scrubbers for the control of fine particle air pollutants. Various wet scrubbers, their engineering, performance, efficiency, and future are discussed. Tables, formulas, and models are included. (TK)

  16. Workshop 97. Part IV. Proceedings

    International Nuclear Information System (INIS)

    This volume of the Proceedings cover the following branches of science and technology: preservation and creation of the environment, architecture, town planning and visual arts, reliability, production systems and technology, nuclear engineering, transport engineering, and economics and business activities. Out of the contributions, 19 have been input to INIS. (P.A.)

  17. Advanced materials and technologies. Proceedings

    Energy Technology Data Exchange (ETDEWEB)

    Lindroos, V.K.; Alander, T.K.R. [eds.] [Helsinki Univ. of Technology, Otaniemi (Finland). Lab. of Physical Metallurgy and Materials Science

    1995-12-31

    The contents of the proceedings consist of three chapters, of which, the first discusses common megatrends, both nationally and globally, in different fields of materials technology. The second chapter is dealing with novel production and processing of base metals and, finally, the third chapter is related with current achievements and future goals of electronic, magnetic, optical and coating materials and their processing

  18. Workshop 97. Part III. Proceedings

    International Nuclear Information System (INIS)

    This volume of the Proceedings covers the following branches of science and technology: power systems and electrical engineering, electronics and measuring and communication engineering, optics, quantum electronics and photonics, microelectronics, and biomedical engineering. Out of the contributions, 2 have been input to INIS. (P.A.)

  19. International Women's Leadership Conference Proceedings.

    Science.gov (United States)

    Journal of Dental Education, 1999

    1999-01-01

    Presents proceedings of the American Association of Dental Schools' International Women's Leadership Conference. Addresses, panel presentations, and general-sessions topics included leadership training and promotion for women in dental education, women's health issues and research, the glass ceiling, infrastructures for research and training,…

  20. 5 CFR 919.965 - Legal proceedings.

    Science.gov (United States)

    2010-01-01

    ... 5 Administrative Personnel 2 2010-01-01 2010-01-01 false Legal proceedings. 919.965 Section 919.965 Administrative Personnel OFFICE OF PERSONNEL MANAGEMENT (CONTINUED) CIVIL SERVICE REGULATIONS (CONTINUED) GOVERNMENTWIDE DEBARMENT AND SUSPENSION (NONPROCUREMENT) Definitions § 919.965 Legal proceedings. Legal proceedings means any...

  1. 31 CFR 19.965 - Legal proceedings.

    Science.gov (United States)

    2010-07-01

    ... 31 Money and Finance: Treasury 1 2010-07-01 2010-07-01 false Legal proceedings. 19.965 Section 19.965 Money and Finance: Treasury Office of the Secretary of the Treasury GOVERNMENTWIDE DEBARMENT AND SUSPENSION (NONPROCUREMENT) Definitions § 19.965 Legal proceedings. Legal proceedings means any...

  2. Singlet oxygen reactivity in water-rich solvent mixtures

    Directory of Open Access Journals (Sweden)

    Cristina Sousa

    2008-01-01

    Full Text Available The 3-methylindole (3MI oxygenation sensitized by psoralen (PSO has been investigated in 100%, 20% and 5% O2-saturated water/dioxane (H2O/Dx mixtures. The lowering of the ¹O2* chemical rate when water (k chem∆3MI = 1.4 × 109 M-1 s-1 is replaced by deuterated water (k chem∆3MI = 1.9 × 108 M-1 s-1 suggests that hydrogen abstraction is involved in the rate determining step. A high dependence of the chemical rate constant on water concentration in H2O/Dx mixtures was found showing that water molecules are absolutely essential for the success of the 3MI substrate oxidation by ¹O2* in water-rich solvent mixtures.

  3. 16 CFR 3.2 - Nature of adjudicative proceedings.

    Science.gov (United States)

    2010-01-01

    ... 16 Commercial Practices 1 2010-01-01 2010-01-01 false Nature of adjudicative proceedings. 3.2... RULES OF PRACTICE FOR ADJUDICATIVE PROCEEDINGS Scope of Rules; Nature of Adjudicative Proceedings § 3.2 Nature of adjudicative proceedings. Adjudicative proceedings are those formal proceedings conducted...

  4. Dynamic thermodiffusion model for binary liquid mixtures

    Science.gov (United States)

    Eslamian, Morteza; Saghir, M. Ziad

    2009-07-01

    Following the nonequilibrium thermodynamics approach, we develop a dynamic model to emulate thermo-diffusion process and propose expressions for estimating the thermal diffusion factor in binary nonassociating liquid mixtures. Here, we correlate the net heat of transport in thermodiffusion with parameters, such as the mixture temperature and pressure, the size and shape of the molecules, and mobility of the components, because the molecules have to become activated before they can move. Based on this interpretation, the net heat of transport of each component can be somehow related to the viscosity and the activation energy of viscous flow of the same component defined in Eyring’s reaction-rate theory [S. Glasstone, K. J. Laidler, and H. Eyring, The Theory of Rate Processes: The Kinetics of Chemical Reactions, Viscosity, Diffusion and Electrochemical Phenomena (McGraw-Hill, New York, 1941)]. This modeling approach is different from that of Haase and Kempers, in which thermodiffusion is considered as a function of the thermostatic properties of the mixture such as enthalpy. In simulating thermodiffusion, by correlating the net heat of transport with the activation energy of viscous flow, effects of the above mentioned parameters are accounted for, to some extent of course. The model developed here along with Haase-Kempers and Drickamer-Firoozabadi models linked with the Peng-Robinson equation of sate are evaluated against the experimental data for several recent nonassociating binary mixtures at various temperatures, pressures, and concentrations. Although the model prediction is still not perfect, the model is simple and easy to use, physically justified, and predicts the experimental data very good and much better than the existing models.

  5. Radiation-heterogeneous processes in water-hexane mixtures

    International Nuclear Information System (INIS)

    Full text : The results of the heterogeneous radiolysis of hexane and a mixture of water-hexane in the presence of gamma-Al2O3 at different ratios have been presented. It has been found that the radiation-chemical yield of molecular hydrogen G (H2) has been increased with increasing content of hexane

  6. Radiation-heterogeneous processes in water-hexane mixtures

    International Nuclear Information System (INIS)

    Full text : The results of the heterogeneous radiolysis of hexane and a mixture of water-hexane in the presence of γAl2O3 at different ratios have been presented. It has been found that the radiation-chemical yield of molecular hydrogen G (H2) has been increased with increasing content of hexane

  7. Phase equilibria in asymmetric mixtures

    International Nuclear Information System (INIS)

    The simplified version of the Perturbed Hard-Chain Theory (SPHCT) is used to compute the phase equilibria and Henry's constants for mixtures in which the molecules are highly asymmetric both in shape and in the intermolecular potential. These mixtures include binary systems such as CO2/hydrocarbons and hydrocarbons/hydrocarbons, which are of particular interest for the oil industry. For this type of mixtures a single parameter (which is calculated from available experimental data of liquid-vapor equilibrium) is introduced. The approach yields results which compare well with the experimental behavior reported in the literature (Author)

  8. Theoretical and experimental comparison of the Soret coefficient for water-methanol and water-ethanol binary mixtures

    DEFF Research Database (Denmark)

    Saghir, MZ; Jiang, CG; Derawi, Samer;

    2004-01-01

    methanol-water and ethanol-water mixtures at 310.6.5 K temperature and 1 bar pressure with 10% water mass fraction. The results were compared with experimental data (J.K. Platten. in Proceedings of the 5th, International Meeting on Thermodiffusion, (IMT5); Lyngby Aug. 2002 Philos. Mag. 83. Nos. 17-18 (2003...

  9. Characterization of nylon 6/poly(propylene oxide) polymeric mixture by combined NMR techniques

    International Nuclear Information System (INIS)

    Polymeric mixtures aim to improve physical or chemical properties of materials. This mixtures can be compatible or not. The compatibility between polymers determine changes of properties. This work has presented a detailed study where nylon 6 and poly(propylene oxide) mixture was analysed by 13 C NMR in the solid state, and NMR spectra were shown and explained. The molecular mobility as well as the compatibility have been observed and discussed

  10. Effect of Gas Mixture Composition on the Parameters of an Internal Combustion Engine

    OpenAIRE

    Andrej Chríbik; Marián Polóni; Ján Lach

    2012-01-01

    This paper deals with the use of the internal combustion piston engine, which is a drive unit for micro-cogeneration units. The introduction is a brief statement of the nature of gas mixture compositions that are useful for the purposes of combustion engines, together with the basic physical and chemical properties relevant to the burning of this gas mixture. Specifically, we will discuss low-energy gases (syngases) and mixtures of natural gas with hydrogen. The second section describes the c...

  11. Optimal Parameters Multicomponent Mixtures Extruding

    Directory of Open Access Journals (Sweden)

    Ramil F. Sagitov

    2013-01-01

    Full Text Available Experimental research of multicomponent mixtures extruding from production wastes are carried out, unit for production of composites from different types of waste is presented. Having analyzed dependence of multicomponent mixtures extruding energy requirements on die length and components content at three values of angular rate of screw rotation, we received the values of energy requirements at optimal length of the die, angular speed and percent of binding additives.

  12. Performance of asphalt rubber mixtures

    OpenAIRE

    Thives, Liseane Padilha; Trichês, Glicério; Pereira, Paulo A. A.; Pais, Jorge C.

    2010-01-01

    Asphalt rubber mixtures are one of the most promising techniques to extend the service life of asphalt pavement overlays. Asphalt rubber binder is composed of crumb rubber from reclaimed tires and conventional asphalt. The asphalt rubber binder can be obtained through wet process in two different systems: terminal blending (produced at industrial plants) and continuous blending (produced in asphalt plants). This study presents a laboratory evaluation of asphalt rubber mixtures produced with d...

  13. Bayesian Kernel Mixtures for Counts

    OpenAIRE

    Canale, Antonio; David B Dunson

    2011-01-01

    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 deviatio...

  14. Applying Upwind Godunov Methods to Calculate Two—Phase Mixture Conservation Laws

    Science.gov (United States)

    Zeidan, D.

    2010-09-01

    This paper continues a previous work (ICNAAM 2009; AIP Conference Proceedings, 1168, 601-604) on solving a hyperbolic conservative model for compressible gas—solid mixture flow using upwind Godunov methods. The numerical resolution of the model from Godunov first—order upwind and MUSCL—Hancock methods are reported. Both methods are based on the HLL Riemann solver in the framework of finite volume techniques. Calculation results are presented for a series of one—dimensional test problems. The results show that upwind Godunov methods are accurate and robust enough for two—phase mixture conservation laws.

  15. World Bioenergy 2012. Proceedings

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2012-11-01

    -stock use. Sustainability and economy are critical factors for market development, but also the adaptability to the current transport systems. The biofuels need efficient vehicles and motors, to be competitive with current transport solutions. How will the transport sector evolve within the coming years? E) World biorefinery 2012: Biorefineries with co-production of liquid, gaseous and solid biofuels with power, heat and chemicals for efficient and optimal use of biomass is the way forward. But strategies, business models, and technological choices are numerous - torrefaction, pyrolysis, enzymatic evolution, thermal gasification, biogas, syngas production, etc. All major biobased industries are today considering biorefinery concepts. The sessions aim to showcase the current state-of-the-art: the projects, and the technological developments. F) Sustainable bioenergy day: Can we achieve a sustainable market growth for modern bioenergy? This is a common theme for all actors in the bioenergy business sector. The last day of World Bioenergy is dedicated to sustainability. It includes the first ever public dialog forum regarding the coming ISO 13065 standard - Sustainability criteria for bioenergy. Asking all bioenergy stakeholders - how can we guarantee sustainable bioenergy and what could the role of a standard be? Sustainability Bioenergy day is arranged by the Swedish Energy Agency with the support of ISO, SIS and Svebio.

  16. National Hydrogen Roadmap Workshop Proceedings

    Energy Technology Data Exchange (ETDEWEB)

    None

    2002-04-01

    This document summarizes the presentations and suggestions put forth by officials, industry experts and policymakers in their efforts to come together to develop a roadmap for America''s clean energy future and outline the key barriers and needs to achieve the hydrogen vision. The National Hydrogen Roadmap Workshop was held April 2-3, 2002. These proceedings were compiled into a formal report, The National Hydrogen Energy Roadmap, which is also available online.

  17. 34. MPA seminar 2008. Proceedings

    International Nuclear Information System (INIS)

    The proceedings include two introductory lectures: The renaissance of nuclear power - causes and challenges; on the way to the coal fired power plant with 50% efficiency. The other contributions concern the following topics: MPA-IfW-NIMS-Workshop: microstructural evolution (7 contributions), advanced materials (6 contributions), material and damage behaviour (6 contributions), integrity of nuclear plants and components (13 contributions), monitoring and inspection (6 contributions), creep and lifetime analysis (4 contributions), applications to HT components (4 contributions), fracture mechanics (7 components)

  18. Workshop 97. Part I. Proceedings

    International Nuclear Information System (INIS)

    The complete Proceedings, in 4 volumes, contain contributions by staff members of the Czech Technical University in Prague, the Technical University in Brno, and the Technical University (former University of Mining) in Ostrava, covering all branches of science and technology dealt with by the 3 universities. Part I includes contributions in mathematics, physics, engineering informatics and cybernetics, and computers. Out of these, 13 have been input to INIS. (P.A.)

  19. Nuclear Inter Jura'87 Proceedings

    International Nuclear Information System (INIS)

    The Proceedings of the 8. Congress of the International Nuclear Law Association (INLA) contain the papers presented at the Congress and the ensuing discussions. The following topics were dealt with: new orientations of nuclear law - its convergence and discordance with other fields of law; impact of international treaties; comparison with legal provisions of other high-technology sectors and optimization of nuclear law. Finally, the last session examined the Chernobyl accident and the legal gaps it revealed. (NEA)

  20. Proceedings: International conference Reforestation Challenges

    OpenAIRE

    Vladan Ivetić; Dragica Stanković

    2015-01-01

    This book of Proceedings compiles 35 papers presented by researchers and scientists at The International Conference on Reforestation Challenges. Topics included various aspects of reforestation: 1) Planning and management of reforestation programs; 2) Stocktypes and seedlings quality; 3) Monitoring reforestation successes; 4) Planting and seedling-site interaction; 5) Species, intra-species and seed source selection and 6) Plant health in nurseries and plantations. In addition to country repo...

  1. An Eshelbian approach to the nonlinear mechanics of constrained solid-fluid mixtures

    CERN Document Server

    Quiligotti, S; dell'Isola, F

    2010-01-01

    Looking at rational mixture theories within the context of a new perspective, this work aims to put forward a proposal for an Eshelbian approach to the nonlinear mechanics of a constrained solid-fluid mixture, made up of an inhomogeneous poroelastic solid and an inviscid compressible fluid, which do not undergo any chemical reaction.

  2. Phenomenology of deflagration and detonation of hydrogen-air mixtures in water cooled nuclear power plants

    International Nuclear Information System (INIS)

    This paper summarizes fundamentals of the flammability of the hydrogen-air mixtures and hydrogen-air containing added steam or other inerting agent. The flammability behaviour of such gaseous mixtures is described with reference to physical and chemical conditions close enough to those expected in the containment of a nuclear reactor during a LOCA

  3. Model Misspecification: Finite Mixture or Homogeneous?

    OpenAIRE

    Tarpey, Thaddeus; Yun, Dong; Petkova, Eva

    2008-01-01

    A common problem in statistical modelling is to distinguish between finite mixture distribution and a homogeneous non-mixture distribution. Finite mixture models are widely used in practice and often mixtures of normal densities are indistinguishable from homogenous non-normal densities. This paper illustrates what happens when the EM algorithm for normal mixtures is applied to a distribution that is a homogeneous non-mixture distribution. In particular, a population-based EM algorithm for fi...

  4. Analysis of asphalt mixtures on town roads

    OpenAIRE

    Glavica, Primož

    2006-01-01

    Asphalt mixtures are most commonly used composite for construction of top layers of different drive ways. By definition asphalt mixtures are composed of crushed rock, fill, bitumen and additives. Percentage of individual components wary according to the purpose asphalt mixture is to be used for. Asphalt mixtures must be capable of enduring different types of load. According to the type of load asphalt mixtures are divided into asphalt mixtures used for supporting layers and asp...

  5. Bioassay-based risk assessment of complex mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Donnelly, K.C.; Huebner, H.J. [Texas A and M Univ., College Station, TX (United States). Dept. of Veterinary Anatomy and Public Health

    1996-12-31

    The baseline risk assessment often plays an integral role in various decision-making processes at Superfund sites. The present study reports on risk characterizations prepared for seven complex mixtures using biological and chemical analysis. Three of the samples (A, B, and C) were complex mixtures of polycyclic aromatic hydrocarbons (PAHs) extracted from coal tar; while four samples extracted from munitions-contaminated soil contained primarily nitroaromatic hydrocarbons. The chemical-based risk assessment ranked sample C as least toxic, while the risk associated with samples A and B was approximately equal. The microbial bioassay was in general agreement for the coal tar samples. The weighted activity of the coal tar extracts in Salmonella was 4,960 for sample C, and 162,000 and 206,000 for samples A and B, respectively. The bacterial mutagenicity of 2,4,6-trinitrotoluene contaminated soils exhibited an indirect correlation with chemical-based risk assessment. The aqueous extract of sample 004 induced 1,292 net revertants in Salmonella, while the estimated risk to ingestion and dermal adsorption was 2E-9. The data indicate that the chemical-based risk assessment accurately predicted the genotoxicity of the PAHs, while the accuracy of the risk assessment for munitions contaminated soils was limited due to the presence of metabolites of TNT degradation. The biological tests used in this research provide a valuable compliment to chemical analysis for characterizing the genotoxic risk of complex mixtures.

  6. Rabbit neonates and human adults perceive a blending 6-component odor mixture in a comparable manner.

    Directory of Open Access Journals (Sweden)

    Charlotte Sinding

    Full Text Available Young and adult mammals are constantly exposed to chemically complex stimuli. The olfactory system allows for a dual processing of relevant information from the environment either as single odorants in mixtures (elemental perception or as mixtures of odorants as a whole (configural perception. However, it seems that human adults have certain limits in elemental perception of odor mixtures, as suggested by their inability to identify each odorant in mixtures of more than 4 components. Here, we explored some of these limits by evaluating the perception of three 6-odorant mixtures in human adults and newborn rabbits. Using free-sorting tasks in humans, we investigated the configural or elemental perception of these mixtures, or of 5-component sub-mixtures, or of the 6-odorant mixtures with modified odorants' proportion. In rabbit pups, the perception of the same mixtures was evaluated by measuring the orocephalic sucking response to the mixtures or their components after conditioning to one of these stimuli. The results revealed that one mixture, previously shown to carry the specific odor of red cordial in humans, was indeed configurally processed in humans and in rabbits while the two other 6-component mixtures were not. Moreover, in both species, such configural perception was specific not only to the 6 odorants included in the mixture but also to their respective proportion. Interestingly, rabbit neonates also responded to each odorant after conditioning to the red cordial mixture, which demonstrates their ability to perceive elements in addition to configuration in this complex mixture. Taken together, the results provide new insights related to the processing of relatively complex odor mixtures in mammals and the inter-species conservation of certain perceptual mechanisms; the results also revealed some differences in the expression of these capacities between species putatively linked to developmental and ecological constraints.

  7. Simultaneous Spectrophotometric Determination of Mixtures of Food Colorants

    Directory of Open Access Journals (Sweden)

    mad Reza Oveisi

    2003-07-01

    Full Text Available Mixtures of food colorants, containing new coccine , ponceaue 6R and scarlet GN were simultaneously analyzed by spectrophotometry without previous chemical separation. Sixty mixtures of colorants with three-components were evaluated and the spectrograms were smoothed through the use of seven experimental points. The multivariate data consisted of normal, first- and second-derivative absorbance spectra (∆λ=5 nm registered from 300-650 nm . The data obtained from experiments were processed by PLS method and the proposed method was applied satisfactorily for determination of these colorants in two commercial food products.

  8. Incompressible Navier–Stokes equations from Boltzmann equations for reacting mixtures

    International Nuclear Information System (INIS)

    Incompressible Navier–Stokes equations for gas mixtures are derived from Boltzmann kinetic models in a suitable fluid dynamic limit. We consider polyatomic gases, each one endowed with a discrete set of internal energy levels. Specifically, we deal with a mixture of four polyatomic gases also undergoing chemical reactions. In the Maxwell molecule case, diffusion coefficients and contributions due to inelastic scattering and to chemical reactions may be explicitly computed. (paper)

  9. Interactions of a pesticide/heavy metal mixture in marine bivalves: a transcriptomic assessment

    OpenAIRE

    Boatti Lara; Negri Alessandro; Banni Mohamed; Dondero Francesco; Dagnino Alessandro; Viarengo Aldo

    2011-01-01

    Abstract Background Mixtures of chemicals present in aquatic environments may elicit toxicity due to additive or synergistic effects among the constituents or, vice versa, the adverse outcome may be reduced by antagonistic interactions. Deviations from additivity should be explained either by the perturbations of toxicokinetic parameters and/or chemical toxicodynamics. We addressed this important question in marine mussels exposed subchronically to a binary mixture made of two wide-spread pol...

  10. TOUGH2, Unsaturated Ground Water and Heat Transfer - T2VOC, H2O, Air, VOC Flow Simulation in Porous Multidimensional Media - iTOUGH2, Inverse Modeling for TOUGH2 Multiphase Flow Simulators - TOUGHREACT, Chemically reactive non-isothermal flows of multiphase fluids in porous and fractured media - TMVOCV1.0, Multicomponent, multiphase, nonisothermal flows of water, soil gas, volatile organic chemicals (VOCs) - ECO2N, a TOUGH2 fluid property module for mixtures of water-NaCl-CO2

    International Nuclear Information System (INIS)

    1 - Description of program or function: TOUGH2V2.0 is a new and improved version of TOUGH2 for simulating fluid flow and heat transfer in porous media. It is upwardly compatible with and includes all of the capabilities of the earlier version, including the flexibility to handle different fluid mixtures (water, water with tracer; water, CO2; water, air; water, air, with vapor pressure lowering; and water, hydrogen), facilities for processing of geometric data (computational grids), and an internal version control system to ensure referenceability of code applications. Improvements in TOUGH2V2.0 include (1) several new EOS modules for different fluid mixtures, including brines and water-soluble and volatile tracers, (2) enhanced capabilities for previously released fluid property modules, (3) description of diffusion and dispersion in multiphase systems, (4) strongly coupled flow and transport processes, (5) coupling between flow in geothermal reservoirs and well-bores in two-phase conditions, (6) tracer transport with sorption and radioactive decay, (7) flow in media with strong heterogeneity, and (8) a new package of preconditioned conjugate gradient routines for more robust solution of numerically difficult problems. In addition, numerous enhancements were made to facilitate applications to more diverse and demanding flow problems. The TZVOC code for three phase flow of water, air, and a non-aqueous phase liquid (NAPL) has been fully integrated into and is now part of the TOUGH2V2.0 program package. TOUGH2V2.0 comes with a new self-contained users guide that includes technical specifications, a complete reference of input data formats and a collection of sample problems. TOUGH2V2.0 is a multi-dimensional numerical model for simulating the coupled transport of water, vapor, air, and other fluids, and heat in porous and fractured media. iTOUGH2 (inverse TOUGH2) is a computer program that provides inverse modeling capabilities for the TOUGH2 code, a simulator for

  11. Mixtures of Product Components versus Mixtures of Dependence Trees

    Czech Academy of Sciences Publication Activity Database

    Grim, Jiří; Pudil, P.

    Cham: Springer, 2015, s. 365-382. (Studies in Computational Intelligence. 620). ISBN 978-3-319-26393-9. [IJCCI 2014 - International Joint Conference on Computational Intelligence (Rome/Italy). Rome (IT), 22.10.2014-24.10.2014] R&D Projects: GA ČR(CZ) GA14-02652S Grant ostatní: GA ČR(CZ) GAP403/12/1557 Institutional support: RVO:67985556 Keywords : Product mixtures * Mixtures of Dependence Trees * EM algorithm Subject RIV: BD - Theory of Information http://library.utia.cas.cz/separaty/2016/RO/grim-0452538.pdf

  12. Proceedings of the 2nd Annual Tank Integrity Workshop

    International Nuclear Information System (INIS)

    The production of nuclear weapons in the United States to help defeat the Axis Powers in World War II and to maintain national security during the Cold War required the construction of a vast nuclear facility complex in the 1940's and 1950's. These facilities housed nuclear reactors needed for the production of plutonium and chemical plants required to separate the plutonium from fission products and to convert plutonium compounds to pure plutonium metal needed for weapons. The chemical separation processes created ''high-level waste'' that was eventually stored in metal tanks at each site. These wastes and other nuclear wastes still reside at sites throughout the United States. At the Savannah River Site, a facility (the Defense Waste Processing Facility) has been constructed to vitrify stored high-level waste that will be transferred to the national high-level waste repository. The liquid wastes at the Idaho National Engineering and Environmental Laboratory have largely been stabilized as a mixture of oxide particles (calcines) but liquid wastes remain to be treated and the calcined waste will probably require further processing into a final, stable form. The Hanford Site is now in the initial stages of waste treatment facility design and has a large number of single-shell tanks, many of which are known to be leaking into the subsurface. The Oak Ridge Site, which did not produce ''high level waste'' as defined by DOE, continues to rely upon tank storage for nuclear wastes although most of its older liquid wastes have been successfully stabilized. The site at West Valley, near Buffalo, NY, marks the location of the nation's only commercial fuel reprocessing facility. As a result of an agreement with the state of New York, the DOE assumed a major role in the stabilization of the high-level waste stored at this site and its eventual closure. A feature common to many of these sites is that they must continue to rely upon large underground tanks to store dangerously

  13. Toxicity of a binary mixture on Daphnia magna: biological effects of uranium and selenium isolated and in mixture

    International Nuclear Information System (INIS)

    Among the multiple substances that affect freshwater ecosystems, uranium and selenium are two pollutants found worldwide in the environment, alone and in mixture. The aim of this thesis work was to investigate the effect of uranium and selenium mixture on daphnia (Daphnia magna). Studying effects of a mixture requires the assessment of the effect of single substances. Thus, the first experiments were performed on single substance. Acute toxicity data were obtained: EC50 48h = 0, 39±0, 04 mg.L-1 for uranium and EC50 48h 1, 86±0, 85 mg.L-1 for selenium. Chronic effects were also studied. Data on fecundity showed an EC10 reproduction of 14±7 μg. L-1 for uranium and of 215±25 μg. L-1 for selenium. Uranium-selenium mixture toxicity experiments were performed and revealed an antagonistic effect. This study further demonstrates the importance of taking into consideration different elements in binary mixture studies such as the choice of reference models (concentration addition or independent action), statistical method, time exposure and endpoints. Using integrated parameters like energy budget was shown to be an interesting way to better understand interactions. An approach including calculation of chemical speciation in the medium and bioaccumulation measurements in the organism permits assumptions to be made on the nature of possible interactions between mixture components (toxico-dynamic et toxico-kinetic interactions). (author)

  14. Procedural Justice in Dutch Administrative Court Proceedings

    OpenAIRE

    2014-01-01

    In this paper we discuss recent developments in administrative court proceedings in the Netherlands, called the New Approach. Along with developments leading to the New Approach, it became clear that the insights from research on procedural justice deserve particular attention. The goals of the judge's actions in this respect are both that the proceedings are fair and just and that parties perceive the way they are being treated during proceedings as fair and just.Within the New Approach we d...

  15. Procedural Justice in Dutch Administrative Law Proceedings

    OpenAIRE

    Verburg, André; Schueler, Ben

    2014-01-01

    In this paper we discuss recent developments in administrative court proceedings in the Netherlands, called the New Approach. Along with developments leading to the New Approach, it became clear that the insights from research on procedural justice deserve particular attention. The goals of the judge's actions in this respect are both that the proceedings are fair and just and that parties perceive the way they are being treated during proceedings as fair and just. Within the New Approach we ...

  16. 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.

  17. Separating Underdetermined Convolutive Speech Mixtures

    DEFF Research Database (Denmark)

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

    2006-01-01

    A limitation in many source separation tasks is that the number of source signals has to be known in advance. Further, in order to achieve good performance, the number of sources cannot exceed the number of sensors. In many real-world applications these limitations are too restrictive. We propose 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...... techniques with binary time-frequency masking. In the proposed method, the number of source signals is not assumed to be known in advance and the number of sources is not limited to the number of microphones. Our approach needs only two microphones and the separated sounds are maintained as stereo signals....

  18. Preparation of conducting solid mixtures

    International Nuclear Information System (INIS)

    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

  19. Polarized mixtures with ionic tracers

    Energy Technology Data Exchange (ETDEWEB)

    Magnarelli, Lorenzo [Dipartimento di Ingegneria Meccanica e Strutturale, Universita di Trento, Via Mesiano 77, 38050 Povo, Trento (Italy)], E-mail: lorenzo.magnarelli@ing.unitn.it

    2009-08-14

    A model of a polarized mixture is developed and the effects of migration of ions are also accounted for. The rate of the polarization power in some way furnishes power to the mixture. The electrical external power is calculated and by means of a requirement of invariance of the power, the standard balance laws are deduced. The ions dissolved in the mixture and subject to the electric field are considered like tracers and their migration is discussed. We show that their migration is ruled by the Nernst-Planck equation. In the final section, we adapt the description of the model to the setting of complex bodies and the microstructural evolution equations are derived.

  20. Polarized mixtures with ionic tracers

    International Nuclear Information System (INIS)

    A model of a polarized mixture is developed and the effects of migration of ions are also accounted for. The rate of the polarization power in some way furnishes power to the mixture. The electrical external power is calculated and by means of a requirement of invariance of the power, the standard balance laws are deduced. The ions dissolved in the mixture and subject to the electric field are considered like tracers and their migration is discussed. We show that their migration is ruled by the Nernst-Planck equation. In the final section, we adapt the description of the model to the setting of complex bodies and the microstructural evolution equations are derived.

  1. 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. PMID:22523437

  2. On the Use of Mixture Toxicity Assessment in REACH and the Water Framework Directive

    DEFF Research Database (Denmark)

    Syberg, Kristian; Jensen, Trine Susanne; Cedergreen, Nina;

    2009-01-01

    This review seeks to connect the scientific theory of mixture toxicity to its implementation within different regulatory frameworks. The aim is to demonstrate how mixture toxicity assessment can be more thoroughly integrated into the European chemical regulations, REACH, and the Water Framework...... of how the methods could be applied within REACH and the WFD. It is concluded that concentration addition should be applied as a default model for mixture toxicity assessment. Furthermore, it is concluded that REACH and the WFD only include mixture toxicity assessments in specific situations. However...

  3. Premature reproductive aging in female rats after developmental exposure to mixtures of endocrine disrupters

    DEFF Research Database (Denmark)

    Jacobsen, Pernille Rosenskjold; Petersen, Marta Axelstad; Christiansen, Sofie;

    2013-01-01

    Long-lasting and delayed reproductive effects of developmental exposure to mixtures of environmental chemicals were investigated in female rats. Wistar rats were dosed during gestation and lactation to mixtures of endocrine disrupters, and effects in offspring were studied. The mixtures consisted...... effects on ovary development may account for the observed effect. This study demonstrated that developmental exposure of rats to mixtures of endocrine disrupters can induce long-lasting adverse effects manifested as early reproductive senescence even though no effects on estrous cyclicity were observed in...

  4. Results of Section 4 Chemical Testing

    Data.gov (United States)

    U.S. Environmental Protection Agency — The Toxic Substances Control Act (TSCA) requires that data be developed on the effect of chemical substances and mixtures on health and the environment. This data...

  5. Molecular Thermodynamics for Chemical Process Design

    Science.gov (United States)

    Prausnitz, J. M.

    1976-01-01

    Discusses that aspect of thermodynamics which is particularly important in chemical process design: the calculation of the equilibrium properties of fluid mixtures, especially as required in phase-separation operations. (MLH)

  6. Accelerated Hazards Mixture Cure Model

    OpenAIRE

    Zhang, Jiajia; Peng, Yingwei

    2009-01-01

    We propose a new cure model for survival data with a surviving or cure fraction. The new model is a mixture cure model where the covariate effects on the proportion of cure and the distribution of the failure time of uncured patients are separately modeled. Unlike the existing mixture cure models, the new model allows covariate effects on the failure time distribution of uncured patients to be negligible at time zero and to increase as time goes by. Such a model is particularly useful in some...

  7. Genotoxicity of complex mixtures: CHO cell mutagenicity assay

    Energy Technology Data Exchange (ETDEWEB)

    Frazier, M.E.; Samuel, J.E.

    1985-02-01

    A Chinese hamster ovary (CHO) mammalian cell assay was used to evaluate the genotoxicity of complex mixtures (synthetic fuels). The genotoxicity (mutagenic potency) of the mixtures increased as the temperature of their boiling range increased. Most of the genotoxicity in the 750/sup 0/F+ boiling-range materials was associated with the neutral polycyclic aromatic hydrocarbon (PAH) fractions. Chemical analysis data indicate that the PAH fractions of high-boiling coal liquids contain a number of known chemical carcinogens, including five- and six-ring polyaromatics (e.g., benzo(a)pyrene) as well as four- and five-ring alkyl-substituted PAH (e.g., methylchrysene and dimethylbenzanthracenes); concentrations are a function of boiling point (bp). In vitro genotoxicity was also detected in fractions of nitrogen-containing polyaromatic compounds, as well as in those with aliphatics of hydroxy-containing PAH. Mutagenic activity of some fractions was detectable in the CHO assay in the absence of an exogenous metabolic activation system; in some instances, addition of exogenous enzymes and cofactors inhibited expression of the direct-acting mutagenic potential of the fraction. These data indicate that the organic matrix of the chemical fraction determines whether, and to what degree, various mutagens are expressed in the CHO assay. Therefore, the results of biological assays of these mixtures must be correlated with chemical analyses for proper interpretation of these data. 29 references, 16 figures, 4 tables.

  8. Toxicity of synthetic naphthenic acids and mixtures of these to fish liver cells.

    Science.gov (United States)

    Tollefsen, Knut Erik; Petersen, Karina; Rowland, Steven J

    2012-05-01

    Environmental concerns have been raised over the toxicity of crude naphthenic acids (NA) originating from oil exploration activities offshore, oil sands exploitation onshore, and use of refined NA as wood preservatives, tire additives, and in various other applications. The NA exist in highly complex mixtures, so the toxic effects of the individual acids are rarely known. The present study investigated the relationships between the chemical structures of a range of synthetic alicyclic and aromatic acids and their acute toxicities both as single chemicals and as complex mixtures in a primary culture of rainbow trout (Oncorhynchus mykiss) hepatocytes. The combined toxicity of multicomponent mixtures of these NA was assessed using the concept of concentration addition (CA) and independent action (IA) prediction. All of the acids tested were moderately toxic, with EC(50) values in the range 108-405 μM (24-89 mg L(-1)) and 188-656 μM (43-148 mg L(-1)) when assessed by effects on metabolic inhibition or loss of membrane integrity, respectively. Binary and 6-compound mixture of NA caused combined toxicity according to the concept of additivity, although slight deviations from additivity were observed at a few mixture concentrations. Single NA and mixtures of NA with similar structures to those tested herein probably contribute to the toxicity of complex natural mixtures of NA. Toxicity tests on three commercial NA mixtures showed that these exhibited highly variable toxicities themselves probably reflecting their chemical heterogeneity. PMID:22462822

  9. Future water quality monitoring - Adapting tools to deal with mixtures of pollutants in water resource management

    OpenAIRE

    Altenburger, R; Ait-Aissa, S; Antczak, P; Backhaus, T.; Barceló, D; Seiler, T-B; Brion, F.; W. Busch; Chipman, K; de Alda, ML; de Aragão Umbuzeiro, G; Escher, BI; Falciani, F; Faust, M; Focks, A

    2015-01-01

    Environmental quality monitoring of water resources is challenged with providing the basis for safeguarding the environment against adverse biological effects of anthropogenic chemical contamination from diffuse and point sources. While current regulatory efforts focus on monitoring and assessing a few legacy chemicals, many more anthropogenic chemicals can be detected simultaneously in our aquatic resources. However, exposure to chemical mixtures does not necessarily translate into adverse b...

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

    DEFF Research Database (Denmark)

    Medvedev, Oleg; Shapiro, Alexander

    2003-01-01

    coefficients for a three-component mixture consists of four Fickian diffusion coefficients, each being reported separately. However, the Onsager theory predicts the existence of only three independent coefficients, as one of them disappears due to the symmetry requirement. Re-calculation of the Fickian......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 into...

  11. Effects of different endocrine disruptor (EDC) mixtures on gene expression in neonatal rat brain regions

    DEFF Research Database (Denmark)

    Lichtensteiger, Walter; Bassetti-Gaille, Catherine; Faass, Oliver; Boberg, Julie; Christiansen, Sofie; Hass, Ulla; Kortenkamp, Andreas; Schlumpf, Margret

    EDC mixtures on gene expression in developing brain. Amix (8 anti-androgenic chemicals), Emix (4 estrogenic chemicals) and Tmix (Amix + Emix + paracetamol recently identified as anti-androgenic) were administered by oral gavage to rat dams from gestational day 7 until weaning, at doses corresponding...... time RT PCR of selected mRNA species in MPO and ventromedial hypothalamus (VMH) of all dose groups. Microarray analyses revealed mixture- and sex-specific effects on gene expression patterns. The majority of genes affected by an individual mixture was selective for that mixture. Real time RT PCR of...... individual mRNAs demonstrated treatment- and sex-dependent differences between MPO and VMH. Effects were dose-dependent. Prominent are effects on the expression of genes involved in excitatory glutamatergic synapse formation and function. These data indicate that effects of complex EDC mixtures on developing...

  12. Proceedings

    International Nuclear Information System (INIS)

    Twenty-four papers were presented at this conference attended by representatives from 16 countries. The papers discussed the design and implementation of control and instrumentation systems in nuclear power plants, the licensing of software by regulatory agencies, and life-cycle issues. (L.L.)

  13. Proceedings

    International Nuclear Information System (INIS)

    Invited talks presented at a two-week workshop on pion-nucleon interactions are briefly presented and a summary of the discussions that took place is added. Topics covered include quantum chromodynamics and the weak NNπ vertex, pionic effects in the weak decays of nuclei, the isobar-doorway approach to the pion-nucleus interaction, multiple scattering approaches, the phenomenology of non-elastic reactions within the isobar-doorway picture, a field theory of pion-nucleus interaction, and the quark structure of the nucleon in nuclei. (LL)

  14. Proceedings

    International Nuclear Information System (INIS)

    Text of the papers presented at the 1996 Canadian Conference on Dam Safety were provided. The Conference took place in Niagara Falls. It comprised seven sessions, and a poster session. Two sessions each were devoted to dam safety, the economics of dam safety, and a number of case histories, while one session dealt with tailings dams. There were a total of 24 papers, plus six presentations in the poster session

  15. Proceedings

    International Nuclear Information System (INIS)

    These fifteen papers were presented by students in nuclear engineering from the Universities of Toronto and Manitoba, the Royal Military College, Ecole Polytechnique, McMaster University, and Trent University. They cover the areas of CANDU, SLOWPOKE and MAPLE reactor systems and fuel, applied nucleonics, and simulation theory and thermalhydraulics. (L.L.)

  16. Proceedings of wide band gap semiconductors

    International Nuclear Information System (INIS)

    This book contains the proceedings of wide band gap semiconductors. Wide band gap semiconductors are under intense study because of their potential applications in photonic devices in the visible and ultraviolet part of the electromagnetic spectrum, and devices for high temperature, high frequency and high power electronics. Additionally, due to their unique mechanical, thermal, optical, chemical, and electronic properties many wide band gap semiconductors are anticipated to find applications in thermoelectric, electrooptic, piezoelectric and acoustooptic devices as well as protective coatings, hard coatings and heat sinks. Material systems covered in this symposium include diamond, II-VI compounds, III-V nitrides, silicon carbide, boron compounds, amorphous and microcrystalline semiconductors, chalcopyrites, oxides and halides. The various papers addressed recent experimental and theoretical developments. They covered issues related to crystal growth (bulk and thin films), structure and microstructure, defects, doping, optoelectronic properties and device applications. A theoretical session was dedicated to identifying common themes in the heteroepitaxy and the role of defects in doping, compensation and phase stability of this unique class of materials. Important experimental milestones included the demonstrations of bright blue injection luminescence at room temperatures from junctions based on III-V nitrides and a similar result from multiple quantum wells in a ZnSe double heterojunction at liquid nitrogen temperatures

  17. Quantum yield measurement in the chemical reactions of laser-excited Zn and Rb atoms with molecules

    International Nuclear Information System (INIS)

    Graphical abstract: A new method of determining the rate constants of chemical reactions proceeding with participant of Zn(4p 3P1) and Rb(11P3/2) atoms has been introduced. The method is based on the investigation of the spatial and temporary behavior of the atoms and their interaction with reagent-gas molecules in a carrier gas flow. For the excitation of the atom pulsed monochromatic resonance laser radiation was used. The interaction of electronically excited atoms with reagent-gas molecules causes a decrease in the concentration of atoms owing to chemical and physical quenching processes. Registering the change in the atom concentration at the end of the flow, one can evaluate the rate a constants of the reaction in which of stable chemical compounds forms. These investigations are necessary for the laser isotope separation. - Abstract: In the present paper, we introduce a method for measuring the apparent quantum yield θap and the rate-constant values of the physical kp and chemical kc quenching of electronically excited Zn and Rb atoms by gas molecules. The method is based on measuring the concentration of the atoms at the end of their flow in a mixture with a reagent-gas and a carrier gas, in the region where all quenching and secondary processes are already over. The concentration of the atoms was determined from measured absorbed energy of resonance laser radiation. The rate constants and the cross-sections of the chemical and physical quenching of Zn(3P10) and Rb(11P3/2) atoms with several molecules have been determined. For some collisions the quantum yield was found to be close to unity. The method may find applications in laser photochemical isotope separation and in measuring the rate constants of reactions proceeding with participation of ground state atoms.

  18. Uranium hexafluoride: Safe handling, processing, and transporting: Conference proceedings

    Energy Technology Data Exchange (ETDEWEB)

    Strunk, W.D.; Thornton, S.G. (eds.)

    1988-01-01

    This conference seeks to provide a forum for the exchange of information and ideas of the safety aspects and technical issue related to the handling of uranium hexafluoride. By allowing operators, engineers, scientists, managers, educators, and others to meet and share experiences of mutual concern, the conference is also intended to provide the participants with a more complete knowledge of technical and operational issues. The topics for the papers in the proceedings are widely varied and include the results of chemical, metallurgical, mechanical, thermal, and analytical investigations, as well as the developed philosophies of operational, managerial, and regulatory guidelines. Papers have been entered individually into EDB and ERA. (LTN)

  19. Proceedings of the workshop on elementary process in hydrogen recycling

    International Nuclear Information System (INIS)

    On September 7 and 8, 1981, a workshop was held at the Institute of Plasma Physics to review the state of the art of the study of elementary processes in hydrogen recycling in fusion reactors. The processes considered are reflection, adsorption, trapping, particle-induced emission, chemical sputtering, and diffusion in metals. The present report is the proceedings of the workshop and contains rather comprehensive reviews each on the processes considered. The workshop was held as part of the joint research program of data compilation at the Research Information Center, Institute of Plasma Physics. (author)

  20. Advances in surface engineering. V. 1. Fundamentals of coatings. Proceedings

    International Nuclear Information System (INIS)

    The scientific and technical research papers in these three volumes, on advances in surface engineering, cover the fundamentals of coatings, process technology and engineering applications, and are based on the proceedings of the May 1996 conference of the same name, held at the University of Northumbria. High temperature corrosion, aqueous corrosion, wear and fatigue are covered in Volume 1. Volume 2 includes papers on various surface engineering technologies including physical and chemical vapour deposition, thermal methods, plasmas and welds, lasers, peening and electrochemistry. Applications of surface engineering to the biomedical, aerospace, automotive, cutting tools and manufacturing, power generation and marine industries are discussed in Volume 3. (UK)

  1. Proceedings of Seminar on Emerging Environmental Issues in Pakistan

    International Nuclear Information System (INIS)

    The seminar on emerging environmental issues in Pakistan was held from December 5-7, 1998, in Islamabad, Pakistan. The nature and magnitude of environmental contamination, and who is exposed to it, depend not only on scientific and technological factors but also reflect economic, political, social and many other influences. In the process of creating social and economic benefits to society, industrial production generates hazardous waste and chemical contaminants that impact negatively on quality of life. The main emphases in this proceedings are on different type pollution and their impacts on humane life. (A.B.)

  2. Uranium hexafluoride: Safe handling, processing, and transporting: Conference proceedings

    International Nuclear Information System (INIS)

    This conference seeks to provide a forum for the exchange of information and ideas of the safety aspects and technical issue related to the handling of uranium hexafluoride. By allowing operators, engineers, scientists, managers, educators, and others to meet and share experiences of mutual concern, the conference is also intended to provide the participants with a more complete knowledge of technical and operational issues. The topics for the papers in the proceedings are widely varied and include the results of chemical, metallurgical, mechanical, thermal, and analytical investigations, as well as the developed philosophies of operational, managerial, and regulatory guidelines. Papers have been entered individually into EDB and ERA

  3. Proceedings of the 33rd annual meeting of the American Association of Cost Engineers

    International Nuclear Information System (INIS)

    This book contains the proceedings of the 33rd annual meeting of the AACE under the following groupings: Project management; Capital cost estimating; Computer applications; Planning and scheduling; Management systems; Capital cost control; Manufacturing costs; Utility cost management; Environmental costs; Power plant costs; and Chemical process industry costs

  4. Proceedings of the 38. Brazilian Congress on Ceramics; 2. Meeting of Miners and Consumers. v. 3

    International Nuclear Information System (INIS)

    These proceedings include the papers presented at the 38. Brazilian Congress on Ceramics and at the 2. Meeting of Miners and Consumers. The third volume is dedicated to the following topics: magnetic, optical and chemical ceramics; development of techniques and equipment for ceramic characterization; fabrication processes; glasses; cements and biomaterials. (C.G.C.)

  5. Chemical Emergencies

    Science.gov (United States)

    When a hazardous chemical has been released, it may harm people's health. Chemical releases can be unintentional, as in the case of an ... the case of a terrorist attack with a chemical weapon. Some hazardous chemicals have been developed by ...

  6. Thermodynamics of mixtures containing alkoxyethanols

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez, Juan Antonio [G.E.T.E.F., Departamento de Fisica Aplicada, Facultad de Ciencias, Universidad de Valladolid, 47071 Valladolid (Spain)], E-mail: jagl@termo.uva.es; Mozo, Ismael; Fuente, Isaias Garcia de la; Cobos, Jose Carlos [G.E.T.E.F., Departamento de Fisica Aplicada, Facultad de Ciencias, Universidad de Valladolid, 47071 Valladolid (Spain); Riesco, Nicolas [Department of Earth Science and Engineering, Imperial College London, Exhibition Road, London SW7 2AZ (United Kingdom)

    2008-09-30

    The Flory model is applied to predict the isobaric expansion coefficients, {alpha}{sub P}, isentropic, {kappa}{sub S}, and isothermal, {kappa}{sub T}, compressibilities and speeds of sound, u, of the highly complex mixtures: hydroxyether + alkane, + dibutylether, + 1-butanol or + 2-methoxyethanol, 1-alkanol + alkane, and 1-alkanol + dibutylether. Predictions were obtained using the energetic parameter, {chi}{sub 12}, determined from values of excess enthalpies, H{sup E}, and from values of the excess isochoric internal energies, U{sub V}{sup E}, at equimolar composition. No meaningful differences exist between such predictions. Deviations between experimental and calculated values are lower than 2% for mixtures containing alkoxyethanols. Poorer results are obtained for 1-alkanol + dibutylether mixtures with deviations up to 5%. It is shown that predictions on {alpha}{sub P}, {kappa}{sub S}, {kappa}{sub T}, and u essentially depend on structural effects and not on the orientational effects present in the studied mixtures. Results are improved using {chi}{sub 12} values fitted to molar excess volumes. In this case, deviations are similar to those obtained from semiempirical models as free length theory, collision factor theory, or Nomoto or Junjie equations.

  7. P-V-T property of a tetrafluoroethylene and propylene mixture

    International Nuclear Information System (INIS)

    The relation between pressure and temperature of a tetrafluoroethylene and propylene mixture was measured at constant volume to obtain chemical engineering data for design of the polymerization apparatus. From this measurement, P-V-T property of the mixtures of various compositions at different densities was determined. Critical points for the mixture compositions were determined from the pressure-temperature curves. The critical temperature vs. propylene concentration of the mixture is not proportional. The compressibility factors calculated with the critical points are in good agreement with the z-chart proposed by Weber. The critical points are thus reasonable, so thereby physical properties of the mixtures can be estimated. Saturated liquid densities of the mixtures of various compositions could thus be estimated. (auth.)

  8. A novel coarsening mechanism of droplets in immiscible fluid mixtures

    Science.gov (United States)

    Shimizu, Ryotaro; Tanaka, Hajime

    2015-06-01

    In our daily lives, after shaking a salad dressing, we see the coarsening of oil droplets suspended in vinegar. Such a demixing process is observed everywhere in nature and also of technological importance. For a case of high droplet density, domain coarsening proceeds with inter-droplet collisions and the resulting coalescence. This phenomenon has been explained primarily by the so-called Brownian-coagulation mechanism: stochastic thermal forces exerted by molecules induce random motion of individual droplets, causing accidental collisions and subsequent interface-tension-driven coalescence. Contrary to this, here we demonstrate that the droplet motion is not random, but hydrodynamically driven by the composition Marangoni force due to an interfacial tension gradient produced in each droplet as a consequence of composition correlation among droplets. This alters our physical understanding of droplet coarsening in immiscible liquid mixtures on a fundamental level.

  9. 14 CFR 302.13 - Consolidation of proceedings.

    Science.gov (United States)

    2010-01-01

    ... PROCEEDINGS) PROCEDURAL REGULATIONS RULES OF PRACTICE IN PROCEEDINGS Rules of General Applicability § 302.13... of its business and to the ends of justice and will not unduly delay the proceedings. Although...

  10. Proteomics based compositional analysis of complex cellulase-hemicellulase mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Chundawat, Shishir P.; Lipton, Mary S.; Purvine, Samuel O.; Uppugundla, Nirmal; Gao, Dahai; Balan, Venkatesh; Dale, Bruce E.

    2011-10-07

    Efficient deconstruction of cellulosic biomass to fermentable sugars for fuel and chemical production is accomplished by a complex mixture of cellulases, hemicellulases and accessory enzymes (e.g., >50 extracellular proteins). Cellulolytic enzyme mixtures, produced industrially mostly using fungi like Trichoderma reesei, are poorly characterized in terms of their protein composition and its correlation to hydrolytic activity on cellulosic biomass. The secretomes of commercial glycosyl hydrolase producing microbes was explored using a proteomics approach with high-throughput quantification using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Here, we show that proteomics based spectral counting approach is a reasonably accurate and rapid analytical technique that can be used to determine protein composition of complex glycosyl hydrolase mixtures that also correlates with the specific activity of individual enzymes present within the mixture. For example, a strong linear correlation was seen between Avicelase activity and total cellobiohydrolase content. Reliable, quantitative and cheaper analytical methods that provide insight into the cellulosic biomass degrading fungal and bacterial secretomes would lead to further improvements towards commercialization of plant biomass derived fuels and chemicals.

  11. Interactive Chemical Reactivity Exploration

    CERN Document Server

    Haag, Moritz P; Bosson, Mael; Redon, Stephane; Reiher, Markus

    2014-01-01

    Elucidating chemical reactivity in complex molecular assemblies of a few hundred atoms is, despite the remarkable progress in quantum chemistry, still a major challenge. Black-box search methods to find intermediates and transition-state structures might fail in such situations because of the high-dimensionality of the potential energy surface. Here, we propose the concept of interactive chemical reactivity exploration to effectively introduce the chemist's intuition into the search process. We employ a haptic pointer device with force-feedback to allow the operator the direct manipulation of structures in three dimensions along with simultaneous perception of the quantum mechanical response upon structure modification as forces. We elaborate on the details of how such an interactive exploration should proceed and which technical difficulties need to be overcome. All reactivity-exploration concepts developed for this purpose have been implemented in the Samson programming environment.

  12. XXVII. Days of Radiation Protection. Conference Proceedings

    International Nuclear Information System (INIS)

    The publication has been set up as a proceedings of the conference dealing with health protection during work with ionizing radiation for different activities which involve the handling of ionizing radiation sources. The main conference topics are focused on current problems in radiation protection and radioecology. In this proceedings totally 83 papers are published

  13. 37 CFR 255.7 - Future proceedings.

    Science.gov (United States)

    2010-07-01

    ... 37 Patents, Trademarks, and Copyrights 1 2010-07-01 2010-07-01 false Future proceedings. 255.7 Section 255.7 Patents, Trademarks, and Copyrights COPYRIGHT OFFICE, LIBRARY OF CONGRESS COPYRIGHT... MAKING AND DISTRIBUTING PHONORECORDS § 255.7 Future proceedings. The procedures specified in 17...

  14. 28 CFR 0.13 - Legal proceedings.

    Science.gov (United States)

    2010-07-01

    ... 28 Judicial Administration 1 2010-07-01 2010-07-01 false Legal proceedings. 0.13 Section 0.13 Judicial Administration DEPARTMENT OF JUSTICE ORGANIZATION OF THE DEPARTMENT OF JUSTICE Office of the Attorney General § 0.13 Legal proceedings. (a) Each Assistant Attorney General and Deputy...

  15. Proceedings of Asia congress on radiation protection

    International Nuclear Information System (INIS)

    203 articles were collected in the proceedings. The contents of the proceedings included the principle and practices of radiation protection, biological effects of radiation, radiation monitoring, protection in medical and other fields, radiation dosimetry, nuclear energy and the environment, natural radiation, radioactive waste management, and other radiation protection issues

  16. Dissipative particle dynamics simulation study on the binary mixture phase separation coupled with polymerization.

    Science.gov (United States)

    Liu, Hong; Qian, Hu-Jun; Zhao, Ying; Lu, Zhong-Yuan

    2007-10-14

    The influence of polymerization on the phase separation of binary immiscible mixtures has been investigated by the dissipative particle dynamics simulations in two dimensions. During polymerization, the bulk viscosity increases, which consequently slows down the spinodal decomposition process. The domain size growth is monitored in the simulations. The absence of 23 exponent for inertial hydrodynamic mechanism clearly reflects the suppressing effect of polymerization on the phase separation. Due to the increasing viscosity, the individual phase may be trapped in a metastable stage instead of the lamellar morphology identified for symmetric mixtures. Moreover, the polymerization induced phase separation in the binary miscible mixture has been studied. The domain growth is strongly dependent on the polymerization probability, which is naturally related to the activation energy for polymerization. The observed complex phase separation behavior is attributed to the interplay between the increasing thermodynamic driving force for phase separation and the increasing viscosity that suppresses phase separation as the polymerization proceeds. PMID:17935435

  17. Proceedings of the Second APEC Coal Flow Seminar Proceedings

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-12-05

    This proceedings includes papers presented at the Second APEC Coal Flow Seminar held at Shanghai in December, 1995. Three keynote speeches were presented, and two panel discussions were held. `Medium-term outlook for coal trade,` `Energy and the environment,` and `Progress with environmental control technology and technical exchanges between economies` were presented as keynote speeches. In the panel discussions, `Achieving low environmental impact from coal production and utilization` and `How to tackle environmental issues related to coal` were discussed. The Panel 1 was divided into Part 1 and Part 2. In the Part 1, overview of current environmental protection policy measures was discussed in relation to coal production and use in economies where coal consumption has been increasing significantly. In the Part 2, overview of current environmental protection policy measures was discussed in relation to coal production and use in major coal producing and consuming economies. 38 refs., 64 figs., 31 tabs.

  18. Evaluation of Hydrated Lime Filler in Asphalt Mixtures

    Directory of Open Access Journals (Sweden)

    Mohammed Abbas Hasan Al-Jumaily

    2008-01-01

    Full Text Available Mineral filler is one of important materials and affecting on properties and quality of asphalt mixtures .There are different types of mineral filler depended on cost and quality , the matter encourages us to achieve this study to evaluate hydrated lime filler effects on properties of asphalt mixes related with strength and durability. Conventional asphaltic concrete mixtures with Portland cement and soft sandstone fillers and mixtures modified with hydrated lime were evaluated for their fundamental engineering properties as defined by Marshall properties , index of retained strength , indirect tensile strength , permanent deformation characteristics , and fatigue resistance .A typical dense graded mixture employed in construction of surface course pavement in Iraq in accordance with SCRB specifications was used .The materials used in this study included mineral aggregate materials (coarse and fine sizes were originally obtained from Najaf Sea quarries and two grades of asphalt cements produced from Daurah refinery which are D47 and D66 . The physical properties , stiffness modulus and chemical composition are evaluated for the recovered asphalt cement from prepared asphalt mixes containing various filler types .The paper results indicated that the addition of hydrated lime as mineral filler improved the permanent deformation characteristics and fatigue life and the use of hydrated lime will decrease the moisture susceptibility of the asphalt mixtures.

  19. Fission product release from core-concrete mixtures

    International Nuclear Information System (INIS)

    The objective of this research is to measure the amount of strontium, barium, and lanthanum that is vaporized from core-concrete mixtures. The measurements are being done using a transpiration method. Mixtures of limestone-aggregated concrete, urania doped with a small amount of La, Sr, Ba, and Zr oxides, and stainless steel were vaporized at 2150 K from a zirconia crucible into flowing He-6% H2-0.06% H2O (a partial molar free energy of oxygen of -420 kJ). The amounts that were vaporized was determined by weight change and by chemical analyses on condensates. The major phases present in the mixture were inferred from electron probe microanalysis (EPM). They were: (1) urania containing calcia and zirconia, (2) calcium zirconate, (3) a calcium magnesium silicate, and (4) magnesia. About 10% of the zirconia crucible was dissolved by the concrete-urania mixture during the experiment, which accounts for the presence of zirconia-containing major phases. To circumvent the problem of zirconia dissolution, we repeated the experiments using mixtures of the limestone-aggregate concrete and the doped urania in molybdenum crucibles. These studies show that thermodynamic calculations of the release of refractory fission products will yield release fractions that are a factor of sixteen too high if the effects of zirconate formation are ignored

  20. Chemical Production using Fission Fragments

    International Nuclear Information System (INIS)

    Some reactor design considerations of the use of fission recoil fragment energy for the production of chemicals of industrial importance have been discussed previously in a paper given at the Second United Nations International Conference on the Peaceful Uses of Atomic Energy [A/Conf. 15/P.76]. The present paper summarizes more recent progress made on this topic at AERE, Harwell. The range-energy relationship for fission fragments is discussed in the context of the choice of fuel system for a chemical production reactor, and the experimental observation of a variation of chemical effect along the length of a fission fragment track is described for the irradiation of nitrogen-oxygen mixtures. Recent results are given on the effect of fission fragments on carbon monoxide-hydrogen gas mixtures and on water vapour. No system investigated to date shows any outstanding promise for large-scale chemical production. (author)

  1. Using high hydrodynamic fluctuations to obtain water-ethanol mixtures

    OpenAIRE

    Шурчкова, Юлія Олександрівна; Дубовкіна, Ірина Олександрівна

    2016-01-01

    The analysis of the processes that occur in binary systems of water-ethanol: hydration, association, formation of hydrogen bonds. The research of the properties of water systems, namely water-ethanol mixtures processed by discrete-pulsed input of energy are presented. The results of experimental research of the effect of high-frequency oscillations in the hydrodynamic physic-chemical parameters of water systems are obtained. The reductions in the amount of dissolved oxygen in the water-ethano...

  2. Analysis of Forest Foliage Using a Multivariate Mixture Model

    Science.gov (United States)

    Hlavka, C. A.; Peterson, David L.; Johnson, L. F.; Ganapol, B.

    1997-01-01

    Data with wet chemical measurements and near infrared spectra of ground leaf samples were analyzed to test a multivariate regression technique for estimating component spectra which is based on a linear mixture model for absorbance. The resulting unmixed spectra for carbohydrates, lignin, and protein resemble the spectra of extracted plant starches, cellulose, lignin, and protein. The unmixed protein spectrum has prominent absorption spectra at wavelengths which have been associated with nitrogen bonds.

  3. Analysis of complex mixtures--cigarette smoke.

    Science.gov (United States)

    Borgerding, Michael; Klus, Hubert

    2005-07-01

    Mainstream cigarette smoke is a complex mixture that is inhaled into the respiratory system. The physical characteristics and chemical composition of mainstream smoke are reviewed and briefly compared with that of sidestream smoke. Special attention is paid to ageing effects and artifact formation during the sampling and testing of cigarette smoke, with specific examples of artifact formation during sampling discussed (nitrogen dioxide, methyl nitrite, etc.). Historically, the generation of cigarette smoke for chemical and biological testing has been based on standard smoke generation procedures that are intended for product comparisons. More recently, emerging global regulations have called for alternative smoke generation methods, with emphasis on results relevant to conditions of product use, e.g., estimates of maximum smoke emissions. Strategies for establishing such alternative smoke generation methods are discussed and the potential effects of alternative smoking conditions on analytical accuracy and precision are addressed. Current regulatory requirements that include Hoffmann analyte analysis (i.e., constituents reported to be associated with the risks of cigarette smoking) are also summarized and the potential effect of alternative smoke generation methods on individual constituent yields considered. Finally, a limited critique of emerging regulation that relates to mainstream cigarette smoke measurements, including a discussion of recent WHO recommendations, is offered. PMID:16092717

  4. Improving the scientific foundation for mixtures joint toxicity and risk assessment: Contributions from the SOT mixtures project-Introduction

    International Nuclear Information System (INIS)

    Risk assessments are enhanced when policy and other decision-makers have access to experimental science designed to specifically inform key policy questions. Currently, our scientific understanding and science policy for environmental mixtures are based largely on extrapolating from and combining data in the observable range of single chemical toxicity to lower environmental concentrations and composition, i.e., using higher dose data to extrapolate and predict lower dose toxicity. There is a growing consensus that the default assumptions underlying those mixtures risk assessments that are conducted in the absence of actual mixtures data rest on an inadequate scientific database. Future scientific research should both build upon the current science and advance toxicology into largely uncharted territory. More precise approaches to better characterize toxicity of mixtures are needed. The Society of Toxicology (SOT) sponsored a series of panels, seminars, and workshops to help catalyze and improve the design and conduct of experimental toxicological research to better inform risk assessors and decision makers. This paper summarizes the activities of the SOT Mixtures Program and serves as the introductory paper to a series of articles in this issue, which hope to inspire innovative research and challenge the status quo

  5. Asphalt rubber mixtures in Portugal: fatigue resistance

    OpenAIRE

    Miranda, Henrique; Batista, Fátima; Neves, José; Antunes, Maria de Lurdes; Fonseca, Paulo

    2009-01-01

    This paper presents a study concerning the fatigue behaviour of asphalt mixtures with bitumen modified with high content of crumb rubber used in Portugal. For assessing the fatigue behaviour of this type of mixtures, four asphalt mixtures with high content of crumb rubber were used: two field bituminous mixtures – an open-graded and a gap-graded – both with granite aggregates; and two laboratory manufactured bituminous mixtures – an open-graded mixture with granite aggregates and a gap-graded...

  6. PCaPAC 2006 Proceedings

    Energy Technology Data Exchange (ETDEWEB)

    Pavel Chevtsov; Matthew Bickley (Eds.)

    2007-03-30

    The 6-th international PCaPAC (Personal Computers and Particle Accelerator Controls) workshop was held at Jefferson Lab, Newport News, Virginia, from October 24-27, 2006. The main objectives of the conference were to discuss the most important issues of the use of PCs and modern IT technologies for controls of accelerators and to give scientists, engineers, and technicians a forum to exchange the ideas on control problems and their solutions. The workshop consisted of plenary sessions and poster sessions. No parallel sessions were held.Totally, more than seventy oral and poster presentations as well as tutorials were made during the conference, on the basis of which about fifty papers were submitted by the authors and included in this publication. This printed version of the PCaPAC 2006 Proceedings is published at Jefferson Lab according to the decision of the PCaPAC International Program Committee of October 26, 2006.

  7. Mixtures in nonstable Levy processes

    International Nuclear Information System (INIS)

    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

  8. Binary mixtures of chiral gases

    CERN Document Server

    Presilla, Carlo

    2015-01-01

    A possible solution of the well known paradox of chiral molecules is based on the idea of spontaneous symmetry breaking. At low pressure the molecules are delocalized between the two minima of a given molecular potential while at higher pressure they become localized in one minimum due to the intermolecular dipole-dipole interactions. Evidence for such a phase transition is provided by measurements of the inversion spectrum of ammonia and deuterated ammonia at different pressures. In particular, at pressure greater than a critical value no inversion line is observed. These data are well accounted for by a model previously developed and recently extended to mixtures. In the present paper, we discuss the variation of the critical pressure in binary mixtures as a function of the fractions of the constituents.

  9. Proceedings of the second workshop on polarised target materials

    International Nuclear Information System (INIS)

    The proceedings are reported of a second international workshop which was convened to consider the use of polarised targets in nuclear research and in particular the experimental difficulties imposed by the limitations of target materials with respect to their relatively low hydrogen content and susceptibility to radiation damage. Papers presented were entitled: (1) Introduction and general review. (2) Theory of dynamic nuclear polarisation. (3) Radiation induced paramagnetic centres in organic and inorganic materials. (4) Dynamic nuclear polarisation with radiation induced free radicals. (5) Radiation damage of chemically doped materials. (6) Chemical doping. (7) Techniques and instrumentation. (8) The use of polarised nuclei in physics with neutrons. (9) The use of polarised targets in high energy physics. (U.K.)

  10. Proceedings of the joint Russian-American hydrogeology seminar

    Energy Technology Data Exchange (ETDEWEB)

    Tsang, C.F. [ed.] [Lawrence Berkeley National Lab., CA (United States); Mironenko, V. [ed.] [Russian Academy of Sciences, St. Petersburg (Russian Federation). Inst. of Environmental Geology; Pozdniakov, S. [ed.] [Moscow State Univ. (Russian Federation)

    1997-12-31

    Hydrogeology research has been very active in both Russia and the US because of the concerns for migration of radioactive and chemical contaminants in soils and geologic formations, as well as for water problems related to mining and other industrial operations. Russian hydrogeologists have developed various analysis and field testing techniques, sometimes in parallel with US counterparts. These Proceedings come out of a Seminar held to bring together a small group (about 15) of active Russian researchers in geologic flow and transport associated with the disposal of radioactive and chemical wastes either on the soils or through deep injection wells, with a corresponding group (about 25) of American hydrogeologists. The meeting was intentionally kept small to enable informal, detailed and in-depth discussions on hydrogeological issues of common interest. Out of this interaction, the authors hope that, firstly, they will have learned from each other and secondly, that research collaborations will be established where there is the opportunity. This proceedings presents the summaries and viewgraphs from the presentations. What cannot be conveyed here is the warm and cooperative atmosphere of these interactions, both inside and outside the formal sessions, which may well lead to future collaborations.

  11. Proceedings of the joint Russian-American hydrogeology seminar

    International Nuclear Information System (INIS)

    Hydrogeology research has been very active in both Russia and the US because of the concerns for migration of radioactive and chemical contaminants in soils and geologic formations, as well as for water problems related to mining and other industrial operations. Russian hydrogeologists have developed various analysis and field testing techniques, sometimes in parallel with US counterparts. These Proceedings come out of a Seminar held to bring together a small group (about 15) of active Russian researchers in geologic flow and transport associated with the disposal of radioactive and chemical wastes either on the soils or through deep injection wells, with a corresponding group (about 25) of American hydrogeologists. The meeting was intentionally kept small to enable informal, detailed and in-depth discussions on hydrogeological issues of common interest. Out of this interaction, the authors hope that, firstly, they will have learned from each other and secondly, that research collaborations will be established where there is the opportunity. This proceedings presents the summaries and viewgraphs from the presentations. What cannot be conveyed here is the warm and cooperative atmosphere of these interactions, both inside and outside the formal sessions, which may well lead to future collaborations

  12. Mixture component effects on the in vitro dermal absorption of pentachlorophenol

    Energy Technology Data Exchange (ETDEWEB)

    Riviere, J.E.; Qiao, G.; Baynes, R.E.; Brooks, J.D. [Coll. of Veterinary Medicine, North Carolina State Univ., Raleigh, NC (United States); Mumtaz, M. [Agency for Toxic Substances and Disease Registry (ATSDR), Atlanta, GA (United States)

    2001-08-01

    Interactions between chemicals in a mixture and interactions of mixture components with the skin can significantly alter the rate and extent of percutaneous absorption, as well as the cutaneous disposition of a topically applied chemical. The predictive ability of dermal absorption models, and consequently the dermal risk assessment process, would be greatly improved by the elucidation and characterization of these interactions. Pentachlorophenol (PCP), a compound known to penetrate the skin readily, was used as a marker compound to examine mixture component effects using in vitro porcine skin models. PCP was administered in ethanol or in a 40% ethanol/60% water mixture or a 40% ethanol/60% water mixture containing either the rubefacient methyl nicotinate (MNA) or the surfactant sodium lauryl sulfate (SLS), or both MNA and SLS. Experiments were also conducted with {sup 14}C-labelled 3,3',4,4'-tetrachlorobiphenyl (TCB) and 3,3',4,4',5-pentachlorobiphenyl (PCB). Maximal PCP absorption was 14.12% of the applied dose from the mixture containing SLS, MNA, ethanol and water. However, when PCP was administered in ethanol only, absorption was only 1.12% of the applied dose. There were also qualitative differences among the absorption profiles for the different PCP mixtures. In contrast with the PCP results, absorption of TCB or PCB was negligible in perfused porcine skin, with only 0.14% of the applied TCB dose and 0.05% of the applied PCB dose being maximally absorbed. The low absorption levels for the PCB congeners precluded the identification of mixture component effects. These results suggest that dermal absorption estimates from a single chemical exposure may not reflect absorption seen after exposure as a chemical mixture and that absorption of both TCB and PCB are minimal in this model system. (orig.)

  13. Procedural Justice in Dutch Administrative Court Proceedings

    Directory of Open Access Journals (Sweden)

    André Verburg

    2014-11-01

    Full Text Available In this paper we discuss recent developments in administrative court proceedings in the Netherlands, called the New Approach. Along with developments leading to the New Approach, it became clear that the insights from research on procedural justice deserve particular attention. The goals of the judge's actions in this respect are both that the proceedings are fair and just and that parties perceive the way they are being treated during proceedings as fair and just.Within the New Approach we discern five procedural justice elements: (1 respect, (2 voice and due consideration, (3 some influence on how proceedings will continue, (4 an explanation of how the proceedings will continue and (5 direct interpersonal contact.The introduction of the New Approach shows two important bottlenecks in Dutch administrative court proceedings, which are (i the possible or supposed collision between legally right outcomes and  procedural justice and (ii the lack of uniformity and predictability.Although what we describe and discuss in this paper focuses on the Dutch situation, many of these considerations apply to administrative court proceedings in other countries. The themes and difficulties that face the administrative law judge seem to be common to many countries.

  14. Applied chemical engineering thermodynamics

    CERN Document Server

    Tassios, Dimitrios P

    1993-01-01

    Applied Chemical Engineering Thermodynamics provides the undergraduate and graduate student of chemical engineering with the basic knowledge, the methodology and the references he needs to apply it in industrial practice. Thus, in addition to the classical topics of the laws of thermodynamics,pure component and mixture thermodynamic properties as well as phase and chemical equilibria the reader will find: - history of thermodynamics - energy conservation - internmolecular forces and molecular thermodynamics - cubic equations of state - statistical mechanics. A great number of calculated problems with solutions and an appendix with numerous tables of numbers of practical importance are extremely helpful for applied calculations. The computer programs on the included disk help the student to become familiar with the typical methods used in industry for volumetric and vapor-liquid equilibria calculations.

  15. Dysgenesis and histological changes of genitals and perturbations of gene expression in male rats after in utero exposure to antiandrogen mixtures

    DEFF Research Database (Denmark)

    Metzdorff, Stine Broeng; Dalgaard, Majken; Christiansen, Sofie;

    2007-01-01

    for these lesions, nor were there histopathological changes in the testes. Pronounced dysgenesis of external genitals was observed with all doses of the mixture, and severe dysgenesis was seen with a mixture for which the individual compounds caused no effects. A combination of doses of each chemical....... Exposure to antiandrogens, which appears to exert only small effects when judged on a chemical-by-chemical basis, may induce marked responses in concert with, possibly unrecognized, similarly acting chemicals....

  16. Potential Impacts of Spilled Hydraulic Fracturing Fluid Chemicals on Water Resources: Types, volumes, and physical-chemical properties of chemicals

    Science.gov (United States)

    Hydraulic fracturing (HF) fluid chemicals spilled on-site may impact drinking water resources. While chemicals generally make up <2% of the total injected fluid composition by mass, spills may have undiluted concentrations. HF fluids typically consist of a mixture of base flui...

  17. PARTICLE SEGREGATION IN FLUIDIZED BINARY-MIXTURES

    NARCIS (Netherlands)

    HOFFMANN, AC; JANSSEN, LPBM

    1993-01-01

    The particle segregation in fluidised beds consisting of different types of binary mixtures is shown to be governed by the same particle transport processes. The segregation behaviour of both ''different-density mixtures'' and ''equal-density mixtures'', two types of system which until now largely h

  18. 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 f

  19. Mycoflora of mixtures used for feeding horses

    Directory of Open Access Journals (Sweden)

    Ewa Rutkowska

    2014-11-01

    Full Text Available In the article the pathogenic role of fungi isolated from mixtures used for feeding horses is discussed. These mixtures were used instead of substantial fodder. In the period of several to a dozen weeks after the mixtures were given an increased percent of spontaneous abortions ous in pregnant mares was observed.

  20. Some properties of explosive mixtures containing peroxides

    International Nuclear Information System (INIS)

    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

  1. Solid state ionics 3. Materials Research Society Symposium Proceedings, volume 293

    Science.gov (United States)

    Nazri, Gholam A.; Tarascon, Jean M.; Armand, Michel

    This proceedings volume includes most of the invited and contributed papers presented as Symposium U, Solid State Ionics, at the 1992 MRS Fall meeting in Boston, Massachusetts, U.S.A. The Symposium covered material aspects of solid state ionics, theory of ion transfer in solids, ionically and electronically conductive polymers and their application in solid state devices, and various in-situ and ex-situ techniques for materials characterization. The first part of this proceedings volume deals with physics and chemistry of insertion compounds and application of these in advanced solid state batteries. The optical and electrochemical properties of insertion compounds are also presented. The second part of the proceedings deals with ionic and electronic conductive polymers. A new class of rubbery phase polymer electrolytes and their structure-conductivity relationship are presented. Physical and chemical properties of polymer electrolytes and electrodes and their application in solid state devices are presented.

  2. Investigations of reversible thermochromic mixtures

    Science.gov (United States)

    MacLaren, Douglas C.

    Three-component organic thermochromic systems have potential applications in reversible, rewritable thermal printing. In principle, such mixtures could maintain a coloured or non-coloured state at ambient temperature depending on their thermal treatment. These systems generally consist of a functional dye (1--3 mol%), a weakly acidic colour developer (5--25 mol%), and a high-melting organic solvent (75--90 mol%). Colour development occurs at the fusion temperature of the mixture, which triggers the interaction of the dye and developer. Slow cooling of the melt results in an equilibrium state with low colour density, whereas rapid cooling of the melt results in a metastable state with high colour density. The metastable state can be decoloured by heating to an intermediate decolourisation temperature at which the coloured state becomes unstable. Barriers to the widespread use of reversible, rewritable thermochromic materials include problems with colour contrast, colour stability, and decolourisation rates. Development is hindered by a lack of detailed knowledge of the interactions between components in these systems. In this study the developer-dye and developer-solvent interactions were examined for an archetypal dye/developer/solvent thermochromic system. Vibrational spectroscopy, NMR, and thermal analysis were used to examine compounds formed in developer/dye and developer/solvent binary mixtures. Rewritable thermochromic properties such as metastable colour density, equilibrium colour density, and decolourisation rates were examined and discussed in terms of the thermodynamics of the developer/dye and developer/solvent interactions. Observed thermochromic properties are shown to be strongly correlated to a competition between the dye and the solvent for interaction with the developer. Increasing the attractive interaction between the solvent and developer results in enhanced rewritable thermochromic properties.

  3. Proceedings of the seventieth annual convention

    International Nuclear Information System (INIS)

    This book contains the proceedings of the seventeenth annual convention of the Gas Processors Association. Topics covered include: the gas processing industry; regulatory impacts; marketing; environment; new projects and processes; and management

  4. Proceedings of the heavy ion fusion workshop

    Energy Technology Data Exchange (ETDEWEB)

    Arnold, R C [ed.

    1978-01-01

    These proceedings contain reviews of current laboratory programs dealing with inertial fusion driven by beams of heavy ions, as well as several individually abstracted invited talks, workshop reports and contributed papers.

  5. Computer vision for biomedical image applications. Proceedings

    International Nuclear Information System (INIS)

    This book constitutes the refereed proceedings of the First International Workshop on Computer Vision for Biomedical Image Applications: Current Techniques and Future Trends, CVBIA 2005, held in Beijing, China, in October 2005 within the scope of ICCV 20. (orig.)

  6. What is military psychology? Symposium Proceedings

    OpenAIRE

    Arima, James K.

    1980-01-01

    Symposium proceedings: papers presented in a symposium entitled "What is Military Psychology", held on 3 September 1979 at the 87th Annual Convention of the American Psychological Association in New York City

  7. Seventh international mining geology conference 2009. Proceedings

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2009-07-01

    Subjects covered include geological modelling, resource evaluation, underground and open pit grade control, project case studies, geometallurgy and new technologies. The proceedings are also available on CD-ROM (ISBN 978-1-921522-06-2).

  8. Fourth DOE environmental protection information meeting. Proceedings

    International Nuclear Information System (INIS)

    Separate abstracts were prepared for the 51 papers included in this proceedings volume for the Energy Data Base (EDB). All are included in Energy Research Abstracts (ERA); eight are included in Energy Abstracts for Policy Analysis (EAPA)

  9. The Olympia Proceedings. Appendix A: Networks.

    Science.gov (United States)

    School Psychology Review, 1982

    1982-01-01

    Networks in urban school psychology, computers in school psychology, social skills development, and innovative in-service are among 15 in educational psychology listed with purposes and participant names and addresses. The networks were formed at the Olympia Proceedings. (CM)

  10. Advanced fuel cycles. Proceedings of the workshop

    Energy Technology Data Exchange (ETDEWEB)

    Ospina, C.; Stanculescu, A. [eds.

    1995-12-31

    The proceedings enclose the papers presented at the workshop sessions on strategies concerning reactors and fuel cycles, on increased plutonium utilisation in LWRs, on advanced systems, complemented by the workshop summaries and recommendations. figs., tabs., refs.

  11. Advanced fuel cycles. Proceedings of the workshop

    International Nuclear Information System (INIS)

    The proceedings enclose the papers presented at the workshop sessions on strategies concerning reactors and fuel cycles, on increased plutonium utilisation in LWRs, on advanced systems, complemented by the workshop summaries and recommendations. figs., tabs., refs

  12. A modified UNIQUAC equation for mixtures containing self-associating compounds

    Directory of Open Access Journals (Sweden)

    P. A. Pessôa Filho

    2005-09-01

    Full Text Available The UNIQUAC model for the excess Gibbs energy is modified using chemical theory to account for chain-like association occurring in self-associating compounds such as alcohols. The equation considers the alcohol to be a mixture of clusters in chemical equilibrium. The UNIQUAC equation is used to model the behavior of the mixture of clusters, with size and surface parameters related to the number of alcohol molecules involved in their formation. The values of association enthalpy and entropy were obtained through fitting vapor pressure data. The model is used to correlate phase behavior of alcohol-hydrocarbon mixtures at low pressures, presenting excellent results in bubble point calculations. A further extension was made to allow for cross-association, the formation of a hydrogen bond between the molecules of an alcohol and an active solute. This extension was used to model alcohol-aromatic mixtures with equally good results.

  13. Strategies for Transferring Mixtures of Organic Contaminants from Aquatic Environments into Bioassays.

    Science.gov (United States)

    Jahnke, Annika; Mayer, Philipp; Schäfer, Sabine; Witt, Gesine; Haase, Nora; Escher, Beate I

    2016-06-01

    Mixtures of organic contaminants are ubiquitous in the environment. Depending on their persistence and physicochemical properties, individual chemicals that make up the mixture partition and distribute within the environment and might then jointly elicit toxicological effects. For the assessment and monitoring of such mixtures, a variety of cell-based in vitro and low-complexity in vivo bioassays based on algae, daphnids or fish embryos are available. A very important and sometimes unrecognized challenge is how to combine sampling, extraction and dosing to transfer the mixtures from the environment into bioassays, while conserving (or re-establishing) their chemical composition at adjustable levels for concentration-effect assessment. This article outlines various strategies for quantifiable transfer from environmental samples including water, sediment, and biota into bioassays using total extraction or polymer-based passive sampling combined with either solvent spiking or passive dosing. PMID:26804122

  14. Strategies for Transferring Mixtures of Organic Contaminants from Aquatic Environments into Bioassays

    DEFF Research Database (Denmark)

    Jahnke, Annika; Mayer, Philipp; Schäfer, Sabine;

    2016-01-01

    Mixtures of organic contaminants are ubiquitous in the environment. Depending on their persistence and physicochemical properties, individual chemicals that make up the mixture partition and distribute within the environment and might then jointly elicit toxicological effects. For the assessment...... and monitoring of such mixtures, a variety of cell-based in vitro and low-complexity in vivo bioassays based on algae, daphnids or fish embryos are available. A very important and sometimes unrecognized challenge is how to combine sampling, extraction and dosing to transfer the mixtures from the...... environment into bioassays, while conserving (or re-establishing) their chemical composition at adjustable levels for concentration-effect assessment. This article outlines various strategies for quantifiable transfer from environmental samples including water, sediment, and biota into bioassays using total...

  15. Fluctuating hydrodynamics of multi-species reactive mixtures.

    Science.gov (United States)

    Bhattacharjee, Amit Kumar; Balakrishnan, Kaushik; Garcia, Alejandro L; Bell, John B; Donev, Aleksandar

    2015-06-14

    We formulate and study computationally the fluctuating compressible Navier-Stokes equations for reactive multi-species fluid mixtures. We contrast two different expressions for the covariance of the stochastic chemical production rate in the Langevin formulation of stochastic chemistry, and compare both of them to predictions of the chemical master equation for homogeneous well-mixed systems close to and far from thermodynamic equilibrium. We develop a numerical scheme for inhomogeneous reactive flows, based on our previous methods for non-reactive mixtures [Balakrishnan , Phys. Rev. E 89, 013017 (2014)]. We study the suppression of non-equilibrium long-ranged correlations of concentration fluctuations by chemical reactions, as well as the enhancement of pattern formation by spontaneous fluctuations. Good agreement with available theory demonstrates that the formulation is robust and a useful tool in the study of fluctuations in reactive multi-species fluids. At the same time, several problems with Langevin formulations of stochastic chemistry are identified, suggesting that future work should examine combining Langevin and master equation descriptions of hydrodynamic and chemical fluctuations. PMID:26071701

  16. Fluctuating hydrodynamics of multi-species reactive mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Bhattacharjee, Amit Kumar; Donev, Aleksandar [Courant Institute of Mathematical Sciences, New York University, 251 Mercer Street, New York, New York 10012 (United States); Balakrishnan, Kaushik [Jet Propulsion Laboratory, 4800 Oak Grove Drive, Pasadena, California 91109 (United States); Garcia, Alejandro L. [Department of Physics and Astronomy, San Jose State University, 1 Washington Square, San Jose, California 95192 (United States); Bell, John B. [Computational Research Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720 (United States)

    2015-06-14

    We formulate and study computationally the fluctuating compressible Navier-Stokes equations for reactive multi-species fluid mixtures. We contrast two different expressions for the covariance of the stochastic chemical production rate in the Langevin formulation of stochastic chemistry, and compare both of them to predictions of the chemical master equation for homogeneous well-mixed systems close to and far from thermodynamic equilibrium. We develop a numerical scheme for inhomogeneous reactive flows, based on our previous methods for non-reactive mixtures [Balakrishnan , Phys. Rev. E 89, 013017 (2014)]. We study the suppression of non-equilibrium long-ranged correlations of concentration fluctuations by chemical reactions, as well as the enhancement of pattern formation by spontaneous fluctuations. Good agreement with available theory demonstrates that the formulation is robust and a useful tool in the study of fluctuations in reactive multi-species fluids. At the same time, several problems with Langevin formulations of stochastic chemistry are identified, suggesting that future work should examine combining Langevin and master equation descriptions of hydrodynamic and chemical fluctuations.

  17. 19th Radiation Hygiene Days. Conference Proceedings

    International Nuclear Information System (INIS)

    The publication has been set up as a proceedings of the conference dealing with health protection during work with ionizing radiation for different activities which involve the handling of ionizing radiation sources. The proceedings consists of a following chapters: (1) Invited presentation; (2) Nuclear accident: management and instrumentation; (3) Low activity in environmental; (4) Radon: sources, doses and effects; (5) Radiation protection in nuclear medicine; (6) Nuclear power plants: radiation safety. (J.K.)

  18. NRC regulatory information conference: Proceedings

    International Nuclear Information System (INIS)

    This volume of the report provides the proceedings from the Nuclear Regulatory Commission (NRC) Regulatory Information Conference that was held at the Mayflower Hotel, Washington, DC, on April 18, 19, and 20, 1989. This conference was held by the NRC and chaired by Dr. Thomas E. Mosley, Director, Office of Nuclear Reactor Regulations (NRR) and coordinated by S. Singh Bajwa, Chief, Technical Assistance Management Section, NRR. There were approximately 550 participants from nine countries at the conference. The countries represented were Canada, England, Italy, Japan, Mexico, Spain, Taiwan, Yugoslavia, and the United States. The NRC staff discussed with nuclear industry its regulatory philosophy and approach and the bases on which they have been established. Furthermore, the NRC staff discussed several initiatives that have been implemented recently and their bases as well as NRC's expectations for new initiatives to further improve safety. The figures contained in Appendix A to the volume correspond to the slides that were shown during the presentations. Volume 2 of this report contains the formal papers that were distributed at the beginning of the Regulatory Information Conference and other information about the conference

  19. HTS Wire Development Workshop: Proceedings

    Energy Technology Data Exchange (ETDEWEB)

    1994-07-01

    The 1994 High-Temperature Superconducting Wire Development Workshop was held on February 16--17 at the St. Petersburg Hilton and Towers in St. Petersburg, Florida. The meeting was hosted by Florida Power Corporation and sponsored by the US Department of Energy`s Superconductivity Program for Electric Power Systems. The meeting focused on recent high-temperature superconducting wire development activities in the Department of Energy`s Superconductivity Systems program. The meeting opened with a general discussion on the needs and benefits of superconductivity from a utility perspective, the US global competitiveness position, and an outlook on the overall prospects of wire development. The meeting then focused on four important technology areas: Wire characterization: issues and needs; technology for overcoming barriers: weak links and flux pinning; manufacturing issues for long wire lengths; and physical properties of HTS coils. Following in-depth presentations, working groups were formed in each technology area to discuss the most important current research and development issues. The working groups identified research areas that have the potential for greatly enhancing the wire development effort. These areas are discussed in the summary reports from each of the working groups. This document is a compilation of the workshop proceedings including all general session presentations and summary reports from the working groups.

  20. Workshop on confidence limits. Proceedings

    International Nuclear Information System (INIS)

    The First Workshop on Confidence Limits was held at CERN on 17-18 January 2000. It was devoted to the problem of setting confidence limits in difficult cases: number of observed events is small or zero, background is larger than signal, background not well known, and measurements near a physical boundary. Among the many examples in high-energy physics are searches for the Higgs, searches for neutrino oscillations, Bs mixing, SUSY, compositeness, neutrino masses, and dark matter. Several different methods are on the market: the CLs methods used by the LEP Higgs searches; Bayesian methods; Feldman-Cousins and modifications thereof; empirical and combined methods. The Workshop generated considerable interest, and attendance was finally limited by the seating capacity of the CERN Council Chamber where all the sessions took place. These proceedings contain all the papers presented, as well as the full text of the discussions after each paper and of course the last session which was a discussion session. The list of participants and the 'required reading', which was expected to be part of the prior knowledge of all participants, are also included. (orig.)

  1. Combined toxicity of pesticide mixtures on green algae and photobacteria.

    Science.gov (United States)

    Liu, Shu-Shen; Wang, Cheng-Lin; Zhang, Jin; Zhu, Xiang-Wei; Li, Wei-Ying

    2013-09-01

    Different organisms have diverse responses to the same chemicals or mixtures. In this paper, we selected the green algae Chlorella pyrenoidosa (C. pyrenoidosa) and photobacteria Vibrio qinghaiensis sp.-Q67 (V. qinghaiensis) as target organisms and determined the toxicities of six pesticides, including three herbicides (simetryn, bromacil and hexazinone), two fungicides (dodine and metalaxyl) and one insecticide (propoxur), and their mixtures by using the microplate toxicity analysis. The toxicities of three herbicides to C. pyrenoidosa are much higher than those to V. qinghaiensis, and the toxicities of metalaxyl and propoxur to V. qinghaiensis are higher than those to C. pyrenoidosa, while the toxicity of dodine to C. pyrenoidosa is similar to those to V. qinghaiensis. Using the concentration addition as an additive reference model, the binary pesticide mixtures exhibited different toxicity interactions, i.e., displayed antagonism to C. pyrenoidosa but synergism to V. qinghaiensis. However, the toxicities of the multi-component mixtures of more than two components are additive and can be predicted by the concentration addition model. PMID:23816361

  2. GRAVITY PIPELINE TRANSPORT FOR HARDENING FILLING MIXTURES

    Directory of Open Access Journals (Sweden)

    Leonid KROUPNIK

    2015-12-01

    Full Text Available In underground mining of solid minerals becoming increasingly common development system with stowing hardening mixtures. In this case the natural ore array after it is replaced by an artificial excavation of solidified filling mixture consisting of binder, aggregates and water. Such a mixture is prepared on the surface on special stowing complexes and transported underground at special stowing pipelines. However, it is transported to the horizons of a few kilometers, which requires a sustainable mode of motion of such a mixture in the pipeline. Hardening stowing mixture changes its rheological characteristics over time, which complicates the calculation of the parameters of pipeline transportation. The article suggests a method of determining the initial parameters of such mixtures: the status coefficient, indicator of transportability, coefficient of hydrodynamic resistance to motion of the mixture. These indicators characterize the mixture in terms of the possibility to transport it through pipes. On the basis of these indicators is proposed methodology for calculating the parameters of pipeline transport hardening filling mixtures in drift mode when traffic on the horizontal part of the mixture under pressure column of the mixture in the vertical part of the backfill of the pipeline. This technique allows stable operation is guaranteed to provide pipeline transportation.

  3. Modeling mixtures of thyroid gland function disruptors in a vertebrate alternative model, the zebrafish eleutheroembryo

    Energy Technology Data Exchange (ETDEWEB)

    Thienpont, Benedicte; Barata, Carlos [Department of Environmental Chemistry, Institute of Environmental Assessment and Water Research (IDAEA, CSIC), Jordi Girona, 18-26, 08034 Barcelona (Spain); Raldúa, Demetrio, E-mail: drpqam@cid.csic.es [Department of Environmental Chemistry, Institute of Environmental Assessment and Water Research (IDAEA, CSIC), Jordi Girona, 18-26, 08034 Barcelona (Spain); Maladies Rares: Génétique et Métabolisme (MRGM), University of Bordeaux, EA 4576, F-33400 Talence (France)

    2013-06-01

    Maternal thyroxine (T4) plays an essential role in fetal brain development, and even mild and transitory deficits in free-T4 in pregnant women can produce irreversible neurological effects in their offspring. Women of childbearing age are daily exposed to mixtures of chemicals disrupting the thyroid gland function (TGFDs) through the diet, drinking water, air and pharmaceuticals, which has raised the highest concern for the potential additive or synergic effects on the development of mild hypothyroxinemia during early pregnancy. Recently we demonstrated that zebrafish eleutheroembryos provide a suitable alternative model for screening chemicals impairing the thyroid hormone synthesis. The present study used the intrafollicular T4-content (IT4C) of zebrafish eleutheroembryos as integrative endpoint for testing the hypotheses that the effect of mixtures of TGFDs with a similar mode of action [inhibition of thyroid peroxidase (TPO)] was well predicted by a concentration addition concept (CA) model, whereas the response addition concept (RA) model predicted better the effect of dissimilarly acting binary mixtures of TGFDs [TPO-inhibitors and sodium-iodide symporter (NIS)-inhibitors]. However, CA model provided better prediction of joint effects than RA in five out of the six tested mixtures. The exception being the mixture MMI (TPO-inhibitor)-KClO{sub 4} (NIS-inhibitor) dosed at a fixed ratio of EC{sub 10} that provided similar CA and RA predictions and hence it was difficult to get any conclusive result. There results support the phenomenological similarity criterion stating that the concept of concentration addition could be extended to mixture constituents having common apical endpoints or common adverse outcomes. - Highlights: • Potential synergic or additive effect of mixtures of chemicals on thyroid function. • Zebrafish as alternative model for testing the effect of mixtures of goitrogens. • Concentration addition seems to predict better the effect of

  4. Modeling mixtures of thyroid gland function disruptors in a vertebrate alternative model, the zebrafish eleutheroembryo

    International Nuclear Information System (INIS)

    Maternal thyroxine (T4) plays an essential role in fetal brain development, and even mild and transitory deficits in free-T4 in pregnant women can produce irreversible neurological effects in their offspring. Women of childbearing age are daily exposed to mixtures of chemicals disrupting the thyroid gland function (TGFDs) through the diet, drinking water, air and pharmaceuticals, which has raised the highest concern for the potential additive or synergic effects on the development of mild hypothyroxinemia during early pregnancy. Recently we demonstrated that zebrafish eleutheroembryos provide a suitable alternative model for screening chemicals impairing the thyroid hormone synthesis. The present study used the intrafollicular T4-content (IT4C) of zebrafish eleutheroembryos as integrative endpoint for testing the hypotheses that the effect of mixtures of TGFDs with a similar mode of action [inhibition of thyroid peroxidase (TPO)] was well predicted by a concentration addition concept (CA) model, whereas the response addition concept (RA) model predicted better the effect of dissimilarly acting binary mixtures of TGFDs [TPO-inhibitors and sodium-iodide symporter (NIS)-inhibitors]. However, CA model provided better prediction of joint effects than RA in five out of the six tested mixtures. The exception being the mixture MMI (TPO-inhibitor)-KClO4 (NIS-inhibitor) dosed at a fixed ratio of EC10 that provided similar CA and RA predictions and hence it was difficult to get any conclusive result. There results support the phenomenological similarity criterion stating that the concept of concentration addition could be extended to mixture constituents having common apical endpoints or common adverse outcomes. - Highlights: • Potential synergic or additive effect of mixtures of chemicals on thyroid function. • Zebrafish as alternative model for testing the effect of mixtures of goitrogens. • Concentration addition seems to predict better the effect of mixtures of

  5. The Kinetics of Enzyme Mixtures

    Directory of Open Access Journals (Sweden)

    Simon Brown

    2014-03-01

    Full Text Available Even purified enzyme preparations are often heterogeneous. For example, preparations of aspartate aminotransferase or cytochrome oxidase can consist of several different forms of the enzyme. For this reason we consider how different the kinetics of the reactions catalysed by a mixture of forms of an enzyme must be to provide some indication of the characteristics of the species present. Based on the standard Michaelis-Menten model, we show that if the Michaelis constants (Km of two isoforms differ by a factor of at least 20 the steady-state kinetics can be used to characterise the mixture. However, even if heterogeneity is reflected in the kinetic data, the proportions of the different forms of the enzyme cannot be estimated from the kinetic data alone. Consequently, the heterogeneity of enzyme preparations is rarely reflected in measurements of their steady-state kinetics unless the species present have significantly different kinetic properties. This has two implications: (1 it is difficult, but not impossible, to detect molecular heterogeneity using kinetic data and (2 even when it is possible, a considerable quantity of high quality data is required.

  6. Interaction of indium and tin oxides mixture with chloride in the presence of sulfur dioxide

    International Nuclear Information System (INIS)

    Investigation into chemical sublimation of indium and tin chlorides from equimolar mixture of the respective oxides under the atmosphere of chloride and mixture of chlorine and sulfur dioxide at 550-700 deg C is carried out. Mutual effect of indium and tin oxides conducted via gas phase is shown to result in growth of the rate of chloridosublimation of both metals. 6 refs.; 4 figs.; 1 tab

  7. Applicability of linearized Dusty Gas Model for multicomponent diffusion of gas mixtures in porous solids

    OpenAIRE

    Marković Jelena; Omorjan Radovan

    2007-01-01

    The transport of gaseous components through porous media could be described according to the well-known Fick model and its modifications. It is also known that Fick’s law is not suitable for predicting the fluxes in multicomponent gas mixtures, excluding binary mixtures. This model is still frequently used in chemical engineering because of its simplicity. Unfortunately, besides the Fick’s model there is no generally accepted model for mass transport through porous media (membranes, catalysts...

  8. Quasi-Optical Terahertz Microfluidic Devices for Chemical Sensing and Imaging

    OpenAIRE

    Lei Liu; Zhenguo Jiang; Syed (Shawon) Rahman; Md. Itrat Bin Shams; Benxin Jing; Akash Kannegulla; Li-Jing Cheng

    2016-01-01

    We first review the development of a frequency domain quasi-optical terahertz (THz) chemical sensing and imaging platform consisting of a quartz-based microfluidic subsystem in our previous work. We then report the application of this platform to sensing and characterizing of several selected liquid chemical samples from 570–630 GHz. THz sensing of chemical mixtures including isopropylalcohol-water (IPA-H2O) mixtures and acetonitrile-water (ACN-H2O) mixtures have been successfully demonstrate...

  9. Quantitative analysis of the mixtures of illicit drugs using terahertz time-domain spectroscopy

    Science.gov (United States)

    Jiang, Dejun; Zhao, Shusen; Shen, Jingling

    2008-03-01

    A method was proposed to quantitatively inspect the mixtures of illicit drugs with terahertz time-domain spectroscopy technique. The mass percentages of all components in a mixture can be obtained by linear regression analysis, on the assumption that all components in the mixture and their absorption features be known. For illicit drugs were scarce and expensive, firstly we used common chemicals, Benzophenone, Anthraquinone, Pyridoxine hydrochloride and L-Ascorbic acid in the experiment. Then illicit drugs and a common adulterant, methamphetamine and flour, were selected for our experiment. Experimental results were in significant agreement with actual content, which suggested that it could be an effective method for quantitative identification of illicit drugs.

  10. Brain processing of a configural vs elemental odor mixture in the newborn rabbit.

    Science.gov (United States)

    Schneider, Nanette Y; Datiche, Frédérique; Wilson, Donald A; Gigot, Vincent; Thomas-Danguin, Thierry; Ferreira, Guillaume; Coureaud, Gérard

    2016-06-01

    Organisms are surrounded throughout life by chemically complex odors. How individuals process an odorant within a mixture or a mixture as a whole is a key question in neuroethology and chemical senses. This question is addressed here by using newborn rabbits, which can be rapidly conditioned to a new stimulus by single association with the mammary pheromone. After conditioning to ethyl maltol (odorant B), pups behaviorally respond to B and an A'B' mixture (68/32 ratio) but not to ethyl isobutyrate (odorant A) or an AB mixture (30/70 ratio). This suggests elemental and configural perception of A'B' and AB, respectively. We then explored the neural substrates underlying the processing of these mixtures with the hypothesis that processing varies according to perception. Pups were pseudoconditioned or conditioned to B on postnatal day 3 before exposure to B, A'B' or AB on day 4. Fos expression was not similar between groups (mainly in the olfactory bulb and posterior piriform cortex) suggesting a differential processing of the stimuli that might reflect either stimulus complexity or conditioning effect. Thus, the ratio of components in A'B' vs AB leads to differential activation of the olfactory system which may contribute to elemental and configural percepts of these mixtures. In addition, together with recent behavioral data, this highlights that configural perception occurs even in relatively immature animals, emphasizing the value of the newborn rabbit for exploration of odor mixture processing from molecules to brain and behavior. PMID:25982221

  11. Modelagem dos processos químicos em plasmas de misturas gasosas usadas na corrosão de silício. Parte 2: SF6 / O2 Modeling of the chemical processes in the plasma of gaseous mixtures used in the etching of silicon. Part 2: SF6 / O2

    Directory of Open Access Journals (Sweden)

    G. F. Bauerfeldt

    1998-02-01

    Full Text Available In this work, a numerical modeling analysis of the gas-phase decomposition of SF6 / O2 mixtures, in the presence of silicon, was performed. The relative importance of individual processes and the effect of the parameters' uncertainties were determined. The model was compared with experimental data for the plasma etching of silicon and with the calculated results for the CF4 / O2 system. In both systems the main etching agent is the fluorine atom and the concentration of the major species depends on the composition of the mixture. The etching rate is greater for SF6 / O2.

  12. Modelagem dos processos químicos em plasmas de misturas gasosas usadas na corrosão de silício. Parte 1: CF4 / O2 Modeling of the chemical processes in the plasma of gaseous mixtures used in the etching of silicon. Part 1: CF4/O2

    Directory of Open Access Journals (Sweden)

    G. F. Bauerfeldt

    1998-02-01

    Full Text Available The plasma etching of semiconductor surfaces with fluorine-containing compounds has technological interest. Presently, considerable effort is being devoted to understand the chemistry involved. In this work, a numerical modeling analysis of the gas-phase decomposition of CF4/O2 mixtures, in the presence of silicon, was performed. The relative importance of individual processes was determined as well as the effect of the parameters' uncertainties. The results were compared with experimental data. The main etching agent in the system is the fluorine atom. The concentration of the main species, SiF4, CO, CO2 and COF2 depend on the composition of the mixture.

  13. Toxicity of binary mixtures of metals and pyrethroid insecticides to Daphnia magna Straus. Implications for multi-substance risks assessment.

    Science.gov (United States)

    Barata, Carlos; Baird, D J; Nogueira, A J A; Soares, A M V M; Riva, M C

    2006-06-10

    Two different concepts, termed concentration addition (CA) and independent action (IA), describe general relationships between the effects of single substances and their corresponding mixtures allowing calculation of an expected mixture toxicity on the basis of known toxicities of the mixture components. Both concepts are limited to cases in which all substances in a mixture influence the same experimental endpoint, and are usually tested against a "fixed ratio design" where the mixture ratio is kept constant throughout the studies and the overall concentration of the mixture is systematically varied. With this design, interaction among toxic components across different mixture ratios and endpoints (i.e. lethal versus sublethal) is not assessed. In this study lethal and sublethal (feeding) responses of Daphnia magna individuals to single and binary combinations of similarly and dissimilarly acting chemicals including the metals (cadmium, copper) and the pyrethroid insecticides (lambda-cyhalothrin and deltamethrin) were assayed using a composite experimental design to test for interactions among toxic components across mixture effect levels, mixture ratios, lethal and sublethal toxic effects. To account for inter-experiment response variability, in each binary mixture toxicity assay the toxicity of the individual mixture constituents was also assessed. Model adequacy was then evaluated comparing the slopes and elevations of predicted versus observed mixture toxicity curves with those estimated for the individual components. Model predictive abilities changed across endpoints. The IA concept was able to predict accurately mixture toxicities of dissimilarly acting chemicals for lethal responses, whereas the CA concept did so in three out of four pairings for feeding response, irrespective of the chemical mode of action. Interaction effects across mixture effect levels, evidenced by crossing slopes, were only observed for the binary mixture Cd and Cu for lethal effects

  14. Toxicity of binary mixtures of metals and pyrethroid insecticides to Daphnia magna Straus. Implications for multi-substance risks assessment

    Energy Technology Data Exchange (ETDEWEB)

    Barata, Carlos [Laboratory of Environmental Toxicology, Universitat Poltiecnica de Catalunya, CN 150 Km 14.5, Terrassa 08220 (Spain)]. E-mail: barata@intexter.upc.edu; Baird, D.J. [National Water Research Institute (Environment Canada) at Canadian Rivers Institute, 10 Bailey Drive, PO Box 45111, University of New Brunswick, Fredericton E3B 6E1, New Brunswick (Canada); Nogueira, A.J.A. [Departamento de Biologia, Universidade de Aveiro, 3810-193 Aveiro (Portugal); Soares, A.M.V.M. [Departamento de Biologia, Universidade de Aveiro, 3810-193 Aveiro (Portugal); Riva, M.C. [Laboratory of Environmental Toxicology, Universitat Poltiecnica de Catalunya, CN 150 Km 14.5, Terrassa 08220 (Spain)

    2006-06-10

    Two different concepts, termed concentration addition (CA) and independent action (IA), describe general relationships between the effects of single substances and their corresponding mixtures allowing calculation of an expected mixture toxicity on the basis of known toxicities of the mixture components. Both concepts are limited to cases in which all substances in a mixture influence the same experimental endpoint, and are usually tested against a 'fixed ratio design' where the mixture ratio is kept constant throughout the studies and the overall concentration of the mixture is systematically varied. With this design, interaction among toxic components across different mixture ratios and endpoints (i.e. lethal versus sublethal) is not assessed. In this study lethal and sublethal (feeding) responses of Daphnia magna individuals to single and binary combinations of similarly and dissimilarly acting chemicals including the metals (cadmium, copper) and the pyrethroid insecticides ({lambda}-cyhalothrin and deltamethrin) were assayed using a composite experimental design to test for interactions among toxic components across mixture effect levels, mixture ratios, lethal and sublethal toxic effects. To account for inter-experiment response variability, in each binary mixture toxicity assay the toxicity of the individual mixture constituents was also assessed. Model adequacy was then evaluated comparing the slopes and elevations of predicted versus observed mixture toxicity curves with those estimated for the individual components. Model predictive abilities changed across endpoints. The IA concept was able to predict accurately mixture toxicities of dissimilarly acting chemicals for lethal responses, whereas the CA concept did so in three out of four pairings for feeding response, irrespective of the chemical mode of action. Interaction effects across mixture effect levels, evidenced by crossing slopes, were only observed for the binary mixture Cd and Cu for

  15. Toxicity of binary mixtures of metals and pyrethroid insecticides to Daphnia magna Straus. Implications for multi-substance risks assessment

    International Nuclear Information System (INIS)

    Two different concepts, termed concentration addition (CA) and independent action (IA), describe general relationships between the effects of single substances and their corresponding mixtures allowing calculation of an expected mixture toxicity on the basis of known toxicities of the mixture components. Both concepts are limited to cases in which all substances in a mixture influence the same experimental endpoint, and are usually tested against a 'fixed ratio design' where the mixture ratio is kept constant throughout the studies and the overall concentration of the mixture is systematically varied. With this design, interaction among toxic components across different mixture ratios and endpoints (i.e. lethal versus sublethal) is not assessed. In this study lethal and sublethal (feeding) responses of Daphnia magna individuals to single and binary combinations of similarly and dissimilarly acting chemicals including the metals (cadmium, copper) and the pyrethroid insecticides (λ-cyhalothrin and deltamethrin) were assayed using a composite experimental design to test for interactions among toxic components across mixture effect levels, mixture ratios, lethal and sublethal toxic effects. To account for inter-experiment response variability, in each binary mixture toxicity assay the toxicity of the individual mixture constituents was also assessed. Model adequacy was then evaluated comparing the slopes and elevations of predicted versus observed mixture toxicity curves with those estimated for the individual components. Model predictive abilities changed across endpoints. The IA concept was able to predict accurately mixture toxicities of dissimilarly acting chemicals for lethal responses, whereas the CA concept did so in three out of four pairings for feeding response, irrespective of the chemical mode of action. Interaction effects across mixture effect levels, evidenced by crossing slopes, were only observed for the binary mixture Cd and Cu for lethal effects

  16. Mixture distributions in human genetics research.

    Science.gov (United States)

    Schork, N J; Allison, D B; Thiel, B

    1996-06-01

    The use of mixture distributions in genetics research dates back to at least the late 1800s when Karl Pearson applied them in an analysis of crab morphometry. Pearson's use of normal mixture distributions to model the mixing of different species of crab (or 'families' of crab as he referred to them) within a defined geographic area motivated further use of mixture distributions in genetics research settings, and ultimately led to their development and recognition as intuitive modelling devices for the effects of underlying genes on quantitative phenotypic (i.e. trait) expression. In addition, mixture distributions are now used routinely to model or accommodate the genetic heterogeneity thought to underlie many human diseases. Specific applications of mixture distribution models in contemporary human genetics research are, in fact, too numerous to count. Despite this long, consistent and arguably illustrious history of use, little mention of mixture distributions in genetics research is made in many recent reviews on mixture models. This review attempts to rectify this by providing insight into the role that mixture distributions play in contemporary human genetics research. Tables providing examples from the literature that describe applications of mixture models in human genetics research are offered as a way of acquainting the interested reader with relevant studies. In addition, some of the more problematic aspects of the use of mixture models in genetics research are outlined and addressed. PMID:8817796

  17. An integral equation model for warm and hot dense mixtures

    CERN Document Server

    Starrett, C E; Daligault, J; Hamel, S

    2014-01-01

    In Starrett and Saumon [Phys. Rev. E 87, 013104 (2013)] a model for the calculation of electronic and ionic structures of warm and hot dense matter was described and validated. In that model the electronic structure of one "atom" in a plasma is determined using a density functional theory based average-atom (AA) model, and the ionic structure is determined by coupling the AA model to integral equations governing the fluid structure. That model was for plasmas with one nuclear species only. Here we extend it to treat plasmas with many nuclear species, i.e. mixtures, and apply it to a carbon-hydrogen mixture relevant to inertial confinement fusion experiments. Comparison of the predicted electronic and ionic structures with orbital-free and Kohn-Sham molecular dynamics simulations reveals excellent agreement wherever chemical bonding is not significant.

  18. Stability diagrams for complexes in molten mixtures of halide salts

    International Nuclear Information System (INIS)

    The stability of local fourfold coordination for divalent and trivalent metal ions in liquid mixtures of polyvalent metal halides and alkali halides is classified by means of structural coordinates obtained from properties of the elements. In parallel with earlier classifications of compound crystal structures and molecular shapes, the elemental properties are taken from first-principles calculations of valence electron orbitals in atoms, in the form of (i) the nodal radii of Andreoni, Baldereschi and Guizzetti or (ii) the pseudo-potential radii of Zunger and Cohen. As a third alternative we also consider a classification based on Pettifor's phenomenological chemical scale of the elements. The alternative structural classification schemes that are developed from these elemental properties are very successful in distinguishing molten mixtures in which the available experimental evidence indicates stability of ''complexes'', i.e. long-lived fourfold coordination of polyvalent metal ions. (author). 55 refs, 3 figs

  19. Plasma polymerization of an ethylene-nitrogen gas mixture

    Science.gov (United States)

    Hudis, M.; Wydeven, T.

    1975-01-01

    A procedure has been developed whereby nitrogen can be incorporated into an organic film from an ethylene-nitrogen gas mixture using an internal electrode capacitively coupled radio frequency reactor. The presence of nitrogen has been shown directly by infrared transmittance spectra and electron spectroscopic chemical analysis data, and further indirect evidence was provided by dielectric measurements and by the reverse osmosis properties of the film. Preparation of a nitrogen containing film did not require vapor from an organic nitrogen containing liquid monomer. Some control over the bonding and stoichiometry of the polymer film was provided by the added degree of freedom of the nitrogen partial pressure in the gas mixture. This new parameter strongly affected the dielectric properties of the plasma polymerized film and could affect the reverse osmosis behavior.

  20. PURIFICATION AND ENRICHMENT OF BIOGAS IN ASH-WATER MIXTURE

    Directory of Open Access Journals (Sweden)

    Andrzej Brudniak

    2014-10-01

    Full Text Available Biogas, produced in an aerobic digestion process, is a mixture of gases, and that is why its inexpensive and effective valorisation is essential. Research on this process is necessary in order to use biogas as a renewable energy source. The aim of this thesis is to present methods of biogas purification and enrichment in the fly ash - water mixture, that is generated on the base of fly ash produced during burning coal in power industry. Experience presented that the fly ash absorbs CO2 and H2S, even in conventional conditions. The absorption efficiency depends not only on the chemical composition of the ash but also on its physical properties. There was also a strong neutralization of alkaline waste combustion.

  1. The Separation Of Uranium And Molybdenum Mixture Using Zeolite

    International Nuclear Information System (INIS)

    The zeolite was preparated from the Gunung Kidul, Yogyakarta Indonesia natural zeolite, which was washed with 0.1 M HCI solution. Alkali or alkaline earth cations of natural zeolite was exchanged with NH4+ by using 0.5 M of NH4CI and was dried at 200oC. This zeolite product by Chemically activation was used for process separation of (U,Mo) mixture. The separation of (U,Mo) mixture was done by using zeolite of -200 +325 mesh for U = 31,000 ppm and Mo = 100 ppm in 0.05 M H2SO4 solution with time extraction of 1 hour. By using this method a separation factor of U,Mo gained was OA

  2. Synthesis of Copper Nanoparticles Using Mixture of Allylamine and Polyallylamine

    Directory of Open Access Journals (Sweden)

    Rubén Sierra-Ávila

    2015-01-01

    Full Text Available Copper nanoparticles (Cu-NPs with sizes lower than 31 nm were prepared by wet chemical reduction using copper sulfate solution, hydrazine, and mixture of allylamine (AAm and polyallylamine (PAAm as stabilizing agents. The use of AAm/PAAm mixture leads to the formation of Cu and CuO nanoparticles. The resulting nanostructures were characterized by XRD, TGA, and TEM. The average particle diameters were determined by the Debye-Scherrer equation. Analysis by TGA, TEM, GS-MS, and 1HNMR reveals that synthesized NPs with AAm presented a coating with similar characteristics to NPs with PAAm, suggesting that AAm underwent polymerization during the synthesis. The synthesis of NPs using AAm could be a good alternative to reduce production costs.

  3. Thermodynamic properties of fluid mixtures at high pressures and high temperatures. Application to high explosives and to phase diagrams of binary mixtures

    International Nuclear Information System (INIS)

    The free energy for mixtures of about ten species which are chemically reacting is calculated. In order to have accurate results near the freezing line, excess properties are deduced from a modern statistical mechanics theory. Intermolecular potentials for like molecules are fitted to give good agreement with shock experiments in pure liquid samples, and mixture properties come naturally from the theory. The stationary Chapman-Jouguet detonation wave is calculated with a chemical equilibrium computer code and results are in good agreement with experiment for a lot of various explosives. One then study gas-gas equilibria in a binary mixture and show the extreme sensitivity of theoretical phase diagrams to the hypothesis of the model (author)

  4. Semiparametric mixtures of symmetric distributions

    CERN Document Server

    Butucea, Cristina

    2011-01-01

    We consider in this paper the semiparametric mixture of two distributions equal up to a shift parameter. The model is said to be semiparametric in the sense that the mixed distribution is not supposed to belong to a parametric family. In order to insure the identifiability of the model it is assumed that the mixed distribution is symmetric, the model being then defined by the mixing proportion, two location parameters, and the probability density function of the mixed distribution. We propose a new class of M-estimators of these parameters based on a Fourier approach, and prove that they are square root consistent under mild regularity conditions. Their finite-sample properties are illustrated by a Monte Carlo study and a benchmark real dataset is also studied with our method.

  5. Differential effects of a complex organochlorine mixture on the proliferation of breast cancer cell lines

    Energy Technology Data Exchange (ETDEWEB)

    Aube, Michel, E-mail: 4aubem@videotron.ca [Axe de recherche en sante des populations et environnementale, Centre de recherche du Centre hospitalier universitaire de Quebec and Universite Laval, 2875 Boulevard Laurier, Edifice Delta 2, bureau 600, Quebec, QC, Canada G1V 2M2 (Canada); Larochelle, Christian, E-mail: christian.larochelle@inspq.qc.ca [Axe de recherche en sante des populations et environnementale, Centre de recherche du Centre hospitalier universitaire de Quebec and Universite Laval, 2875 Boulevard Laurier, Edifice Delta 2, bureau 600, Quebec, QC, Canada G1V 2M2 (Canada); Ayotte, Pierre, E-mail: pierre.ayotte@inspq.qc.ca [Axe de recherche en sante des populations et environnementale, Centre de recherche du Centre hospitalier universitaire de Quebec and Universite Laval, 2875 Boulevard Laurier, Edifice Delta 2, bureau 600, Quebec, QC, Canada G1V 2M2 (Canada); Laboratoire de Toxicologie, Institut national de sante publique du Quebec, 945 avenue Wolfe, Quebec, QC, Canada G1V 5B3 (Canada)

    2011-04-15

    Organochlorine compounds (OCs) are a group of persistent chemicals that accumulate in fatty tissues with age. Although OCs has been tested individually for their capacity to induce breast cancer cell proliferation, few studies examined the effect of complex mixtures that comprise compounds frequently detected in the serum of women. We constituted such an OC mixture containing 15 different components in environmentally relevant proportions and assessed its proliferative effects in four breast cancer cell lines (MCF-7, T47D, CAMA-1, MDAMB231) and in non-cancerous CV-1 cells. We also determined the capacity of the mixture to modulate cell cycle stage of breast cancer cells and to induce estrogenic and antiandrogenic effects using gene reporter assays. We observed that low concentrations of the mixture (100x10{sup 3} and 50x10{sup 3} dilutions) stimulated the proliferation of MCF-7 cells while higher concentrations (10x10{sup 3} and 5x10{sup 3} dilutions) had the opposite effect. In contrast, the mixture inhibited the proliferation of non-hormone-dependent cell lines. The mixture significantly increased the number of MCF-7 cells entering the S phase, an effect that was blocked by the antiestrogen ICI 182,780. Low concentrations of the mixture also caused an increase in CAMA-1 cell proliferation but only in the presence estradiol and dihydrotestosterone (p<0.05 at the 50x10{sup 3} dilution). DDT analogs and polychlorinated biphenyls all had the capacity to stimulate the proliferation of CAMA-1 cells in the presence of sex steroids. Reporter gene assays further revealed that the mixture and several of its constituents (DDT analogs, aldrin, dieldrin, {beta}-hexachlorocyclohexane, toxaphene) induced estrogenic effects, whereas the mixture and several components (DDT analogs, aldrin, dieldrin and PCBs) inhibited the androgen signaling pathway. Our results indicate that the complex OC mixture increases the proliferation of MCF-7 cells due to its estrogenic potential. The

  6. Differential effects of a complex organochlorine mixture on the proliferation of breast cancer cell lines

    International Nuclear Information System (INIS)

    Organochlorine compounds (OCs) are a group of persistent chemicals that accumulate in fatty tissues with age. Although OCs has been tested individually for their capacity to induce breast cancer cell proliferation, few studies examined the effect of complex mixtures that comprise compounds frequently detected in the serum of women. We constituted such an OC mixture containing 15 different components in environmentally relevant proportions and assessed its proliferative effects in four breast cancer cell lines (MCF-7, T47D, CAMA-1, MDAMB231) and in non-cancerous CV-1 cells. We also determined the capacity of the mixture to modulate cell cycle stage of breast cancer cells and to induce estrogenic and antiandrogenic effects using gene reporter assays. We observed that low concentrations of the mixture (100x103 and 50x103 dilutions) stimulated the proliferation of MCF-7 cells while higher concentrations (10x103 and 5x103 dilutions) had the opposite effect. In contrast, the mixture inhibited the proliferation of non-hormone-dependent cell lines. The mixture significantly increased the number of MCF-7 cells entering the S phase, an effect that was blocked by the antiestrogen ICI 182,780. Low concentrations of the mixture also caused an increase in CAMA-1 cell proliferation but only in the presence estradiol and dihydrotestosterone (p3 dilution). DDT analogs and polychlorinated biphenyls all had the capacity to stimulate the proliferation of CAMA-1 cells in the presence of sex steroids. Reporter gene assays further revealed that the mixture and several of its constituents (DDT analogs, aldrin, dieldrin, β-hexachlorocyclohexane, toxaphene) induced estrogenic effects, whereas the mixture and several components (DDT analogs, aldrin, dieldrin and PCBs) inhibited the androgen signaling pathway. Our results indicate that the complex OC mixture increases the proliferation of MCF-7 cells due to its estrogenic potential. The proliferative effect of the mixture on CAMA-1 cells in

  7. Miniature Chemical Sensor

    Energy Technology Data Exchange (ETDEWEB)

    Andrew C. R. Pipino

    2004-12-13

    A new chemical detection technology has been realized that addresses DOE environmental management needs. The new technology is based on a variant of the sensitive optical absorption technique, cavity ring-down spectroscopy (CRDS). Termed evanescent-wave cavity ring-down spectroscopy (EW-CRDS), the technology employs a miniature solid-state optical resonator having an extremely high Q-factor as the sensing element, where the high-Q is achieved by using ultra-low-attenuation optical materials, ultra-smooth surfaces, and ultra-high reflectivity coatings, as well as low-diffraction-loss designs. At least one total-internal reflection (TIR) mirror is integral to the resonator permitting the concomitant evanescent wave to probe the ambient environment. Several prototypes have been designed, fabricated, characterized, and applied to chemical detection. Moreover, extensions of the sensing concept have been explored to enhance selectivity, sensitivity, and range of application. Operating primarily in the visible and near IR regions, the technology inherently enables remote detection by optical fiber. Producing 11 archival publications, 5 patents, 19 invited talks, 4 conference proceedings, a CRADA, and a patent-license agreement, the project has realized a new chemical detection technology providing >100 times more sensitivity than comparable technologies, while also providing practical advantages.

  8. Predicting the environmental fate properties of petroleum hydrocarbon mixtures

    International Nuclear Information System (INIS)

    The environmental fate and transport of petroleum products for risk assessment can be evaluated based on the physico-chemical properties of an indicator chemical or a surrogate compound, or the whole mixture. A study was conducted to develop a simple representation of the hydrocarbon mixture as if it contained only few constituents, each of which represents a large number of compounds. The products considered are gasoline, diesel fuel, and jet fuel (JP4). Each petroleum hydrocarbon was characterized as a mixture of six constituents: short chain alkanes, long chain alkanes, short chain cycloalkanes and alkenes, long chain cycloalkanes and alkenes, BTEX, and other aromatics. The carbon number used as a cut-off between short and long chain alkanes, alkenes, and cycloalkanes varies with the type of product. Each mixture has different average molecular weight, water solubility, vapor pressure, organic carbon partition coefficient, and air diffusivity. The properties of each constituent of gasoline were derived from the weighted average of all compounds belonging to each constituent group. For diesel fuel and JP4, the properties of each constituent were generated from the properties of the component most representative of the group. Any property that is missing or not available from common literature sources was derived from regression equations developed from the data base for gasoline. These regression equations express the property as function of the number of carbon atoms. The R2 values of the regression equations range from 0.82--0.92. Some case studies involving petroleum product contamination in which the estimated properties were applied are presented

  9. Holographic Superfluidity in Imbalanced Mixtures

    CERN Document Server

    Erdmenger, Johanna; Kerner, Patrick; Ngo, Thanh Hai

    2011-01-01

    We construct superfluid black hole solutions with two chemical potentials. By analogy with QCD, the two chemical potentials correspond to the baryon and isospin symmetries, respectively. We consider two systems: the back-reacted U(2) Einstein-Yang-Mills theory in 4+1 dimensions and the 9+1-dimensional D3/D7 brane setup with two coincident D7-brane probes. In the D7-brane model, the identification of baryon and isospin chemical potential is explicit since the dual field theory is explicitly known. Studying the phase diagram, we find in both systems a quantum phase transition at a critical ratio of the two chemical potentials. However the quantum phase transition is different in the two systems: In the D3/D7 brane setup we always find a second order phase transition, while in the Einstein-Yang-Mills theory, depending on the strength of the back-reaction, we obtain a continuous or first order transition. We expect the continuous quantum phase transition to be BKT-like. We comment on the origin of this differing ...

  10. Proceedings of the Neural Network Workshop for the Hanford Community

    Energy Technology Data Exchange (ETDEWEB)

    Keller, P.E.

    1994-01-01

    These proceedings were generated from a series of presentations made at the Neural Network Workshop for the Hanford Community. The abstracts and viewgraphs of each presentation are reproduced in these proceedings. This workshop was sponsored by the Computing and Information Sciences Department in the Molecular Science Research Center (MSRC) at the Pacific Northwest Laboratory (PNL). Artificial neural networks constitute a new information processing technology that is destined within the next few years, to provide the world with a vast array of new products. A major reason for this is that artificial neural networks are able to provide solutions to a wide variety of complex problems in a much simpler fashion than is possible using existing techniques. In recognition of these capabilities, many scientists and engineers are exploring the potential application of this new technology to their fields of study. An artificial neural network (ANN) can be a software simulation, an electronic circuit, optical system, or even an electro-chemical system designed to emulate some of the brain`s rudimentary structure as well as some of the learning processes that are believed to take place in the brain. For a very wide range of applications in science, engineering, and information technology, ANNs offer a complementary and potentially superior approach to that provided by conventional computing and conventional artificial intelligence. This is because, unlike conventional computers, which have to be programmed, ANNs essentially learn from experience and can be trained in a straightforward fashion to carry out tasks ranging from the simple to the highly complex.

  11. Conference 'Chemistry of hydrides' Proceedings

    International Nuclear Information System (INIS)

    This collection of thesis of conference of Chemistry hydrides presents the results of investigations concerning of base questions of chemistry of nonorganic hydrides, including synthesis questions, studying of physical and chemical properties, thermodynamics, analytical chemistry, investigation of structure, equilibriums in the systems of metal-hydrogen, behaviour of nonorganic hydrides in non-water mediums and applying investigations in the chemistry area and technology of nonorganic hydrides

  12. Joint toxicity of alkoxyethanol mixtures: contribution of in silico applications.

    Science.gov (United States)

    Pohl, H R; Ruiz, P; Scinicariello, F; Mumtaz, M M

    2012-10-01

    Exposure to chemicals occurs often as mixtures. Presented in this paper is information on alkoxyethanols and the impact they might have on human health in combination with some commonly found aliphatic and aromatic compounds. Our studies to evaluate the joint toxicity of these chemicals among themselves and in combination with other chemicals reveal a variety of possible outcomes depending on the exposure scenario. The interactions are predominantly based on metabolic pathways and are common among several solvents and organic compounds. Quantitative structure activity relationship (QSAR) analysis can be used with high confidence to identify chemicals that will interact to influence overall joint toxicity. Potential human exposure to a combination of alkoxyethanol, toluene and substituted benzenes may increase reproductive and developmental disease conditions. Inheritable gene alterations result in changes in the enzyme function in different subpopulations causing variations in quantity and/or quality of particular isoenzymes. These changes are responsible for differential metabolism of chemicals in species, genders, and life stages and are often the basis of a population's susceptibility. Unique genotypes introduced as a function of migration can alter the genetic makeup of any given population. Hence special consideration should be given to susceptible populations while conducting chemical health risk assessments. PMID:22749914

  13. A numerical analysis of the effects of a stratified pre-mixture on homogeneous charge compression ignition combustion

    Energy Technology Data Exchange (ETDEWEB)

    Jamsran, Narankhuu; Lim, Ock Taeck [University of Ulsan, Ulsan (Korea, Republic of)

    2012-06-15

    We investigated the efficacy of fuel stratification in a pre-mixture of dimethyl ether (DME) and n-butane, which have different autoignition characteristics, for reducing the pressure rise rate (PRR) of homogeneous charge compression ignition engines. A new chemical reaction model was created by mixing DME and n-butane and compared with existing chemical reaction models to verify the effects observed. The maximum PRR depended on the mixture ratio. When DME was charged with stratification and n-butane was charged with homogeneity, the maximum PRR was the lowest among all the mixtures studied. Calculations were performed using CHEMKIN and modified using SENKIN software.

  14. A numerical analysis of the effects of a stratified pre-mixture on homogeneous charge compression ignition combustion

    International Nuclear Information System (INIS)

    We investigated the efficacy of fuel stratification in a pre-mixture of dimethyl ether (DME) and n-butane, which have different autoignition characteristics, for reducing the pressure rise rate (PRR) of homogeneous charge compression ignition engines. A new chemical reaction model was created by mixing DME and n-butane and compared with existing chemical reaction models to verify the effects observed. The maximum PRR depended on the mixture ratio. When DME was charged with stratification and n-butane was charged with homogeneity, the maximum PRR was the lowest among all the mixtures studied. Calculations were performed using CHEMKIN and modified using SENKIN software

  15. Numerical simulations of detonations in hydrogen-air and methane-air mixtures

    International Nuclear Information System (INIS)

    Detailed numerical simulations of supersonic reactive flow and gas phase detonation problems are very expensive due to their computer time and memory requirements. The bulk of this cost is in integrating the ordinary differential equations describing chemical reactions. A global induction parameter model has been developed which describes the chemical induction time of a mixture and allows for release of energy over a finite time period. The specific gases for which it has been calibrated are stoichiometric mixtures of hydrogen and methane in air. The relatively inexpensive induction parameter model is then used in time-dependent one- and two-dimensional simualtions of supersonic reactive flows. 29 refs

  16. Evaluating permanent deformation in asphalt rubber mixtures

    OpenAIRE

    Fontes, Liseane P. T. L.; Trichês, Glicério; Pais, Jorge C.; Pereira, Paulo A. A.

    2009-01-01

    Permanent deformation or rutting, one of the most important distresses inflexible pavements, has long been a problem in asphalt mixtures. Throughout the years, researchers have used different test methods lo estimate the performance of asphalt mixtures in relation to rutting. One of the alternatives to reduce permanent deformation in asphalt pavement layers is through the use of mixtures produced with asphalt rubber This work aims at comparing the performance of a conventional dense graded mi...

  17. Microstructural characterisation of rubber modified asphalt mixtures

    OpenAIRE

    Abdul Hassan, Norhidayah

    2013-01-01

    Research to improve the performance of asphalt mixtures through the addition of crumb rubber using the dry process has continued worldwide because of its potential as a recycling option for used tires. For decades, dry mixed rubberised asphalt mixtures have performed inconsistently in field trials and laboratory evaluations. However, current research has revealed that the performance of asphalt mixtures is highly dependent on the characteristics of its internal structure or phase constituents...

  18. Performance-based asphalt mixture design methodology

    Science.gov (United States)

    Ali, Al-Hosain Mansour

    Today, several State D.O.T.s are being investigating the use of tire rubber with local conventional materials. Several of the ongoing investigations identified potential benefits from the use of these materials, including improvements in material properties and performance. One of the major problems is being associated with the transferability of asphalt rubber technology without appropriately considering the effects of the variety of conventional materials on mixture behavior and performance. Typically, the design of these mixtures is being adapted to the physical properties of the conventional materials by using the empirical Marshall mixture design and without considering fundamental mixture behavior and performance. Use of design criteria related to the most common modes of failure for asphalt mixtures, such as rutting, fatigue cracking, and low temperature thermal cracking have to be developed and used for identifying the "best mixture," in term of performance, for the specific local materials and loading conditions. The main objective of this study was the development of a mixture design methodology that considers mixture behavior and performance. In order to achieve this objective a laboratory investigation able to evaluate mixture properties that can be related to mixture performance, (in terms of rutting, low temperature cracking, moisture damage and fatigue), and simulating the actual field loading conditions that the material is being exposed to, was conducted. The results proved that the inclusion of rubber into asphalt mixtures improved physical characteristics such as elasticity, flexibility, rebound, aging properties, increased fatigue resistance, and reduced rutting potential. The possibility of coupling the traditional Marshall mix design method with parameters related to mixture behavior and performance was investigated. Also, the SHRP SUPERPAVE mix design methodology was reviewed and considered in this study for the development of an integrated

  19. Compositional Adjustment of Dirichlet Mixture Priors

    OpenAIRE

    Ye, Xugang; Yu, Yi-Kuo; Altschul, Stephen F.

    2010-01-01

    Dirichlet mixture priors provide a Bayesian formalism for scoring alignments of protein profiles to individual sequences, which can be generalized to constructing scores for multiple-alignment columns. A Dirichlet mixture is a probability distribution over multinomial space, each of whose components can be thought of as modeling a type of protein position. Applied to the simplest case of pairwise sequence alignment, a Dirichlet mixture is equivalent to an implied symmetric substitution matrix...

  20. Radon thematic days - Conference proceedings

    International Nuclear Information System (INIS)

    - Experience feedback from a body authorized to proceed to radon bulk activity measurements (Sylvain Bernhard, Algade); 23 - Perspectives in the radon domain - Views from the French authorities (Emmanuel Briand, DGS); 24 - Perspectives in the radon domain - Views from the French institute of radiation protection and nuclear safety - IRSN (Francois Rollinger, IRSN); 25 - Perspectives in the radon domain - Views from the Swiss federal office of public health - OFSP (Christophe Murith, OFSP)