WorldWideScience

Sample records for chemical analyses conducted

  1. Precise Chemical Analyses of Planetary Surfaces

    Science.gov (United States)

    Kring, David; Schweitzer, Jeffrey; Meyer, Charles; Trombka, Jacob; Freund, Friedemann; Economou, Thanasis; Yen, Albert; Kim, Soon Sam; Treiman, Allan H.; Blake, David; hide

    1996-01-01

    We identify the chemical elements and element ratios that should be analyzed to address many of the issues identified by the Committee on Planetary and Lunar Exploration (COMPLEX). We determined that most of these issues require two sensitive instruments to analyze the necessary complement of elements. In addition, it is useful in many cases to use one instrument to analyze the outermost planetary surface (e.g. to determine weathering effects), while a second is used to analyze a subsurface volume of material (e.g., to determine the composition of unaltered planetary surface material). This dual approach to chemical analyses will also facilitate the calibration of orbital and/or Earth-based spectral observations of the planetary body. We determined that in many cases the scientific issues defined by COMPLEX can only be fully addressed with combined packages of instruments that would supplement the chemical data with mineralogic or visual information.

  2. Proton conduction based on intracrystalline chemical reaction

    International Nuclear Information System (INIS)

    Schuck, G.; Lechner, R.E.; Langer, K.

    2002-01-01

    Proton conductivity in M 3 H(SeO 4 ) 2 crystals (M=K, Rb, Cs) is shown to be due to a dynamic disorder in the form of an intracrystalline chemical equilibrium reaction: alternation between the association of the monomers [HSeO 4 ] 1- and [SeO 4 ] 2- resulting in the dimer [H(SeO 4 ) 2 ] 3- (H-bond formation) and the dissociation of the latter into the two monomers (H-bond breaking). By a combination of quasielastic neutron scattering and FTIR spectroscopy, reaction rates were obtained, as well as rates of proton exchange between selenate ions, leading to diffusion. The results demonstrate that this reaction plays a central role in the mechanism of proton transport in these solid-state protonic conductors. (orig.)

  3. Conducting qualitative research in mental health: Thematic and content analyses.

    Science.gov (United States)

    Crowe, Marie; Inder, Maree; Porter, Richard

    2015-07-01

    The objective of this paper is to describe two methods of qualitative analysis - thematic analysis and content analysis - and to examine their use in a mental health context. A description of the processes of thematic analysis and content analysis is provided. These processes are then illustrated by conducting two analyses of the same qualitative data. Transcripts of qualitative interviews are analysed using each method to illustrate these processes. The illustration of the processes highlights the different outcomes from the same set of data. Thematic and content analyses are qualitative methods that serve different research purposes. Thematic analysis provides an interpretation of participants' meanings, while content analysis is a direct representation of participants' responses. These methods provide two ways of understanding meanings and experiences and provide important knowledge in a mental health context. © The Royal Australian and New Zealand College of Psychiatrists 2015.

  4. Chemical and physical analyses of selected plants and soils from Puerto Rico (1981-1990)

    Science.gov (United States)

    M. J. Sanchez; E. Lopez; A. E. Lugo

    1997-01-01

    This report contains the result of many analyses conducted at the laboratory of the IITF of Puerto Rico between 1981 and 1990. our objective was to make available the chemical and physical data developed for tropical forest ecosystems.

  5. Chemical and physical analyses of selected plants and soils from Puerto Rico (1981-2000)

    Science.gov (United States)

    M.J. Sanchez; E. Lopez; A.E. Lugo

    2015-01-01

    This report contains the results of analyses conducted at the chemistry laboratory of the International Institute of Tropical Forestry in Puerto Rico from 1981 to 2000. The data set includes 109,177 plant analyses and 70,729 soil analyses. We report vegetation chemical data by plant part, species, life zone, soil order, geology, or parent material. Soil data are...

  6. Using Microsoft Office Excel 2007 to conduct generalized matching analyses.

    Science.gov (United States)

    Reed, Derek D

    2009-01-01

    The generalized matching equation is a robust and empirically supported means of analyzing relations between reinforcement and behavior. Unfortunately, no simple task analysis is available to behavior analysts interested in using the matching equation to evaluate data in clinical or applied settings. This technical article presents a task analysis for the use of Microsoft Excel to analyze and plot the generalized matching equation. Using a data-based case example and a step-by-step guide for completing the analysis, these instructions are intended to promote the use of quantitative analyses by researchers with little to no experience in quantitative analyses or the matching law.

  7. USING MICROSOFT OFFICE EXCEL® 2007 TO CONDUCT GENERALIZED MATCHING ANALYSES

    Science.gov (United States)

    Reed, Derek D

    2009-01-01

    The generalized matching equation is a robust and empirically supported means of analyzing relations between reinforcement and behavior. Unfortunately, no simple task analysis is available to behavior analysts interested in using the matching equation to evaluate data in clinical or applied settings. This technical article presents a task analysis for the use of Microsoft Excel to analyze and plot the generalized matching equation. Using a data-based case example and a step-by-step guide for completing the analysis, these instructions are intended to promote the use of quantitative analyses by researchers with little to no experience in quantitative analyses or the matching law. PMID:20514196

  8. Conducting Meta-Analyses Based on p Values

    Science.gov (United States)

    van Aert, Robbie C. M.; Wicherts, Jelte M.; van Assen, Marcel A. L. M.

    2016-01-01

    Because of overwhelming evidence of publication bias in psychology, techniques to correct meta-analytic estimates for such bias are greatly needed. The methodology on which the p-uniform and p-curve methods are based has great promise for providing accurate meta-analytic estimates in the presence of publication bias. However, in this article, we show that in some situations, p-curve behaves erratically, whereas p-uniform may yield implausible estimates of negative effect size. Moreover, we show that (and explain why) p-curve and p-uniform result in overestimation of effect size under moderate-to-large heterogeneity and may yield unpredictable bias when researchers employ p-hacking. We offer hands-on recommendations on applying and interpreting results of meta-analyses in general and p-uniform and p-curve in particular. Both methods as well as traditional methods are applied to a meta-analysis on the effect of weight on judgments of importance. We offer guidance for applying p-uniform or p-curve using R and a user-friendly web application for applying p-uniform. PMID:27694466

  9. Certification of a uranium dioxide reference material for chemical analyses

    International Nuclear Information System (INIS)

    Le Duigou, Y.

    1984-01-01

    This report, issued by the Central Bureau for Nuclear Measurements (CBNM), describes the characterization of a uranium dioxide reference material with accurately determined uranium mass fraction for chemical analyses. The preparation, conditioning, homogeneity tests and the analyses performed on this material are described in Annex 1. The evaluation of the individual impurity results, total of impurities and uranium mass fraction are given in Annex 2. Information on a direct determination of uranium by titration is given in Annex 3. The uranium mass fraction (881.34+-0.13) g.kg -1 calculated in Annex 2 is given on the certificate

  10. Electrical Conductivity of CUXS Thin Film Deposited by Chemical ...

    African Journals Online (AJOL)

    Thin films of CuxS have successfully been deposited on glass substrates using the Chemical Bath Deposition (CBD) technique. The films were then investigated for their electrical properties. The results showed that the electrical conductivities of the CuxS films with different molarities (n) of thiourea (Tu), determined using ...

  11. 3D printable conducting hydrogels containing chemically converted graphene.

    Science.gov (United States)

    Sayyar, Sepidar; Gambhir, Sanjeev; Chung, Johnson; Officer, David L; Wallace, Gordon G

    2017-02-02

    The development of conducting 3D structured biocompatible scaffolds for the growth of electroresponsive cells is critical in the field of tissue engineering. This work reports the synthesis and 3D processing of UV-crosslinkable conducting cytocompatible hydrogels that are prepared from methacrylated chitosan (ChiMA) containing graphenic nanosheets. The addition of chemically converted graphene resulted in mechanical and electrical properties of the composite that were significantly better than ChiMA itself, as well as improved adhesion, proliferation and spreading of L929 fibroblasts cells. The chemically converted graphene/ChiMA hydrogels were amenable to 3D printing and this was used to produce multilayer scaffolds with enhanced mechanical properties through UV-crosslinking.

  12. Toxicity and chemical analyses of airport runoff waters in Poland.

    Science.gov (United States)

    Sulej, Anna Maria; Polkowska, Zaneta; Wolska, Lidia; Cieszynska, Monika; Namieśnik, Jacek

    2014-05-01

    The aim of this study was to assess the ecotoxicological effects of various compounds in complex airport effluents using a chemical and ecotoxicological integrated strategy. The present work deals with the determination of sum of PCBs, PAHs, pesticides, cations, anions, phenols, anionic, cationic, non-ionic detergents, formaldehyde and metals--as well as TOC and conductivity--in runoff water samples collected from 2009 to 2011 at several locations on two Polish international airports. Two microbiotests (Vibrio fischeri bacteria and the crustacean Thamnocephalus platyurus) have been used to determine the ecotoxicity of airport runoff waters. The levels of many compounds exceeded several or even several tens of times the maximum permissible levels. Analysis of the obtained data shows that samples that displayed maximum toxicity towards the bioindicators Vibrio fischeri were not toxic towards Thamnocephalus platyurus. Levels of toxicity towards T. platyurus are strongly correlated with pollutants that originate from the technological operations related to the maintenance of airport infrastructure. The integrated (chemical-ecotoxicological) approach to environmental contamination assessment in and around airports yields extensive information on the quality of the environment. These methodologies can be then used as tools for tracking the environmental fate of these compounds and for assessing the environmental effect of airports. Subsequently, these data will provide a basis for airport infrastructure management.

  13. Chemical Passivation of Li(exp +)-Conducting Solid Electrolytes

    Science.gov (United States)

    West, William; Whitacre, Jay; Lim, James

    2008-01-01

    Plates of a solid electrolyte that exhibits high conductivity for positive lithium ions can now be passivated to prevent them from reacting with metallic lithium. Such passivation could enable the construction and operation of high-performance, long-life lithium-based rechargeable electrochemical cells containing metallic lithium anodes. The advantage of this approach, in comparison with a possible alternative approach utilizing lithium-ion graphitic anodes, is that metallic lithium anodes could afford significantly greater energy-storage densities. A major impediment to the development of such cells has been the fact that the available solid electrolytes having the requisite high Li(exp +)-ion conductivity are too highly chemically reactive with metallic lithium to be useful, while those solid electrolytes that do not react excessively with metallic lithium have conductivities too low to be useful. The present passivation method exploits the best features of both extremes of the solid-electrolyte spectrum. The basic idea is to coat a higher-conductivity, higher-reactivity solid electrolyte with a lower-conductivity, lower-reactivity solid electrolyte. One can then safely deposit metallic lithium in contact with the lower-reactivity solid electrolyte without incurring the undesired chemical reactions. The thickness of the lower-reactivity electrolyte must be great enough to afford the desired passivation but not so great as to contribute excessively to the electrical resistance of the cell. The feasibility of this method was demonstrated in experiments on plates of a commercial high-performance solid Li(exp +)- conducting electrolyte. Lithium phosphorous oxynitride (LiPON) was the solid electrolyte used for passivation. LiPON-coated solid-electrolyte plates were found to support electrochemical plating and stripping of Li metal. The electrical resistance contributed by the LiPON layers were found to be small relative to overall cell impedances.

  14. Procedures for field chemical analyses of water samples

    International Nuclear Information System (INIS)

    Korte, N.; Ealey, D.

    1983-12-01

    A successful water-quality monitoring program requires a clear understanding of appropriate measurement procedures in order to obtain reliable field data. It is imperative that the responsible personnel have a thorough knowledge of the limitations of the techniques being used. Unfortunately, there is a belief that field analyses are simple and straightforward. Yet, significant controversy as well as misuse of common measurement techniques abounds. This document describes procedures for field measurements of pH, carbonate and bicarbonate, specific conductance, dissolved oxygen, nitrate, Eh, and uranium. Each procedure section includes an extensive discussion regarding the limitations of the method as well as brief discussions of calibration procedures and available equipment. A key feature of these procedures is the consideration given to the ultimate use of the data. For example, if the data are to be used for geochemical modeling, more precautions are needed. In contrast, routine monitoring conducted merely to recognize gross changes can be accomplished with less effort. Finally, quality assurance documentation for each measurement is addressed in detail. Particular attention is given to recording sufficient information such that decisions concerning the quality of the data can be easily made. Application of the procedures and recommendations presented in this document should result in a uniform and credible water-quality monitoring program. 22 references, 4 figures, 3 tables

  15. Chemical analyses in the World Coal Quality Inventory

    Science.gov (United States)

    Tewalt, Susan J.; Belkin, Harvey E.; SanFilipo, John R.; Merrill, Matthew D.; Palmer, Curtis A.; Warwick, Peter D.; Karlsen, Alexander W.; Finkelman, Robert B.; Park, Andy J.

    2010-01-01

    The main objective of the World Coal Quality Inventory (WoCQI) was to collect and analyze a global set of samples of mined coal during a time period from about 1995 to 2006 (Finkelman and Lovern, 2001). Coal samples were collected by foreign collaborators and submitted to country specialists in the U.S. Geological Survey (USGS) Energy Program. However, samples from certain countries, such as Afghanistan, India, and Kyrgyzstan, were collected collaboratively in the field with USGS personnel. Samples were subsequently analyzed at two laboratories: the USGS Inorganic Geochemistry Laboratory located in Denver, CO and a commercial laboratory (Geochemical Testing, Inc.) located in Somerset, PA. Thus the dataset, which is in Excel (2003) format and includes 1,580 samples from 57 countries, does not have the inter-laboratory variability that is present in many compilations. Major-, minor-, and trace-element analyses from the USGS laboratory, calculated to a consistent analytical basis (dry, whole-coal) and presented with available sample identification information, are sorted alphabetically by country name. About 70 percent of the samples also have data from the commercial laboratory, which are presented on an as-received analytical basis. The USGS initiated a laboratory review of quality assurance in 2008, covering quality control and methodology used in inorganic chemical analyses of coal, coal power plant ash, water, and sediment samples. This quality control review found that data generated by the USGS Inorganic Geochemistry Laboratory from 1996 through 2006 were characterized by quality practices that did not meet USGS requirements commonly in use at the time. The most serious shortcomings were (1) the adjustment of raw sample data to standards when the instrument values for those standards exceeded acceptable limits or (2) the insufficient use of multiple standards to provide adequate quality assurance. In general, adjustment of raw data to account for instrument

  16. Physico-chemical analyses and corrosion effect of produced water ...

    African Journals Online (AJOL)

    Physico-chemical characteristics of the composite produced water sample used for the study has a higher concentration compared with DPR standard for discharge of produced formation water into surface environment. It was assumed that the corrosion of the coupons was due to presence of high chemical matters in the ...

  17. Chemometrics as a tool to analyse complex chemical mixtures

    DEFF Research Database (Denmark)

    Christensen, J. H.

    Chemical characterisation of contaminant mixtures is important for environmental forensics and risk assessment. The great challenge in future research lies in develop- ing 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 general concept that suitable methods must be rapid and inexpensive, objective with limited human in- tervention...... and at the same time must consider a substantial fraction of compounds in the complex mixture. A combination of a) limited sample preparation, b) rapid chemical screening analysis, c) fast and semi-automatic pre-processing, d) compre- hensive multivariate statistical data analysis and e) objective data evaluation...

  18. Analysing chemical equilibrium conditions when studying butyl acetate synthesis

    OpenAIRE

    Álvaro Orjuela Londoño; Fernando Leiva Lenis; Luis Alejandro Boyacá Mendivelso; Gerardo Rodríguez Niño; Luis María Carballo Suárez

    2010-01-01

    This work studied the liquid phase of acetic acid and butyl alcohol esterification reaction (P atm = 560 mmHg),using an ion exchange resin (Lewatit K-2431) as catalyst. A set of assays were carried out for determining the effect of catalyst load, temperature and molar ratio (acid/alcohol) on chemical equilibrium constant. Components’ selective sorption on the resin matrix was noticed; its effect on equilibrium conditions was verified, by using different acid/alcohol starting ratios. A non-ide...

  19. Physico-Chemical and Bacteriological Analyses of Water Used for ...

    African Journals Online (AJOL)

    Samuel Olaleye

    Physicochemical and bacteriological analyses were carried out on well water, stream water and river water used for drinking and swimming purposes in. Abeokuta, Nigeria. The results obtained were compared with WHO and EPA standards for drinking and recreational water. With the exception of Sokori stream and a well ...

  20. Preliminary analyses on hydrogen diffusion through small break of thermo-chemical IS process hydrogen plant

    International Nuclear Information System (INIS)

    Somolova, Marketa; Terada, Atsuhiko; Takegami, Hiroaki; Iwatsuki, Jin

    2008-12-01

    Japan Atomic Energy Agency has been conducting a conceptual design study of nuclear hydrogen demonstration plant, that is, a thermal-chemical IS process hydrogen plant coupled with the High temperature Engineering Test Reactor (HTTR-IS), which will be planed to produce a large amount of hydrogen up to 1000m 3 /h. As part of the conceptual design work of the HTTR-IS system, preliminary analyses on small break of a hydrogen pipeline in the IS process hydrogen plant was carried out as a first step of the safety analyses. This report presents analytical results of hydrogen diffusion behaviors predicted with a CFD code, in which a diffusion model focused on the turbulent Schmidt number was incorporated. By modifying diffusion model, especially a constant accompanying the turbulent Schmidt number in the diffusion term, analytical results was made agreed well with the experimental results. (author)

  1. Validation of chemical analyses of atmospheric deposition in forested European sites

    Directory of Open Access Journals (Sweden)

    Erwin ULRICH

    2005-08-01

    Full Text Available Within the activities of the Integrated Co-operative Programme on Assessment and Monitoring of Air Pollution Effects on Forests (ICP Forests and of the EU Regulation 2152/2003, a Working Group on Quality Assurance/Quality Control of analyses has been created to assist the participating laboratories in the analysis of atmospheric deposition, soil and soil solution, and leaves/needles. As part of the activity of the WG, this study is a statistical analysis in the field of water analysis of chemical concentrations and relationships between ions, and between conductivity and ions for different types of samples (bulk or wet-only samples, throughfall, stemflow considered in forest studies. About 5000 analyses from seven laboratories were used to establish relationships representative of different European geographic and climatic situations, from northern Finland to southern Italy. Statistically significant differences between the relationships obtained from different types of solutions, interacting with different types of vegetation (throughfall and stemflow samples, broad-leaved trees and conifers and with varying influence of marine salt were tested. The ultimate aim is to establish general relationships between ions, and between conductivity and ions, with relative confidence limits, which can be used as a comparison with those established in single laboratories. The use of such techniques is strongly encouraged in the ICPF laboratories to validate single chemical analyses, to be performed when it is still possible to replicate the analysis, and as a general overview of the whole set of analyses, to obtain an indication of the laboratory performance on a long-term basis.

  2. Lipids: From Chemical Structures, Biosynthesis, and Analyses to Industrial Applications.

    Science.gov (United States)

    Li-Beisson, Yonghua; Nakamura, Yuki; Harwood, John

    2016-01-01

    Lipids are one of the major subcellular components, and play numerous essential functions. As well as their physiological roles, oils stored in biomass are useful commodities for a variety of biotechnological applications including food, chemical feedstocks, and fuel. Due to their agronomic as well as economic and societal importance, lipids have historically been subjected to intensive studies. Major current efforts are to increase the energy density of cell biomass, and/or create designer oils suitable for specific applications. This chapter covers some basic aspects of what one needs to know about lipids: definition, structure, function, metabolism and focus is also given on the development of modern lipid analytical tools and major current engineering approaches for biotechnological applications. This introductory chapter is intended to serve as a primer for all subsequent chapters in this book outlining current development in specific areas of lipids and their metabolism.

  3. Computational Analyses of Complex Flows with Chemical Reactions

    Science.gov (United States)

    Bae, Kang-Sik

    The heat and mass transfer phenomena in micro-scale for the mass transfer phenomena on drug in cylindrical matrix system, the simulation of oxygen/drug diffusion in a three dimensional capillary network, and a reduced chemical kinetic modeling of gas turbine combustion for Jet propellant-10 have been studied numerically. For the numerical analysis of the mass transfer phenomena on drug in cylindrical matrix system, the governing equations are derived from the cylindrical matrix systems, Krogh cylinder model, which modeling system is comprised of a capillary to a surrounding cylinder tissue along with the arterial distance to veins. ADI (Alternative Direction Implicit) scheme and Thomas algorithm are applied to solve the nonlinear partial differential equations (PDEs). This study shows that the important factors which have an effect on the drug penetration depth to the tissue are the mass diffusivity and the consumption of relevant species during the time allowed for diffusion to the brain tissue. Also, a computational fluid dynamics (CFD) model has been developed to simulate the blood flow and oxygen/drug diffusion in a three dimensional capillary network, which are satisfied in the physiological range of a typical capillary. A three dimensional geometry has been constructed to replicate the one studied by Secomb et al. (2000), and the computational framework features a non-Newtonian viscosity model for blood, the oxygen transport model including in oxygen-hemoglobin dissociation and wall flux due to tissue absorption, as well as an ability to study the diffusion of drugs and other materials in the capillary streams. Finally, a chemical kinetic mechanism of JP-10 has been compiled and validated for a wide range of combustion regimes, covering pressures of 1atm to 40atm with temperature ranges of 1,200 K--1,700 K, which is being studied as a possible Jet propellant for the Pulse Detonation Engine (PDE) and other high-speed flight applications such as hypersonic

  4. A coupled theory for chemically active and deformable solids with mass diffusion and heat conduction

    Science.gov (United States)

    Zhang, Xiaolong; Zhong, Zheng

    2017-10-01

    To analyse the frequently encountered thermo-chemo-mechanical problems in chemically active material applications, we develop a thermodynamically-consistent continuum theory of coupled deformation, mass diffusion, heat conduction and chemical reaction. Basic balance equations of force, mass and energy are presented at first, and then fully coupled constitutive laws interpreting multi-field interactions and evolving equations governing irreversible fluxes are constructed according to the energy dissipation inequality and the chemical kinetics. To consider the essential distinction between mass diffusion and chemical reactions in affecting free energy and dissipations of a highly coupled system, we regard both the concentrations of diffusive species and the extent of reaction as independent state variables. This new formulation then distinguishes between the energy contribution from the diffusive species entering the solid and that from the subsequent chemical reactions occurring among these species and the host solid, which not only interact with stresses or strains in different manners and on different time scales, but also induce different variations of solid microstructures and material properties. Taking advantage of this new description, we further establish a specialized isothermal model to predict precisely the transient chemo-mechanical response of a swelling solid with a proposed volumetric constraint that accounts for material incompressibility. Coupled kinetics is incorporated to capture the volumetric swelling of the solid caused by imbibition of external species and the simultaneous dilation arised from chemical reactions between the diffusing species and the solid. The model is then exemplified with two numerical examples of transient swelling accompanied by chemical reaction. Various ratios of characteristic times of diffusion and chemical reaction are taken into account to shed light on the dependency on kinetic time scales of evolution patterns for

  5. Botanical discrimination of Greek unifloral honeys with physico-chemical and chemometric analyses.

    Science.gov (United States)

    Karabagias, Ioannis K; Badeka, Anastasia V; Kontakos, Stavros; Karabournioti, Sofia; Kontominas, Michael G

    2014-12-15

    The aim of the present study was to investigate the possibility of characterisation and classification of Greek unifloral honeys (pine, thyme, fir and orange blossom) according to botanical origin using volatile compounds, conventional physico-chemical parameters and chemometric analyses (MANOVA and Linear Discriminant Analysis). For this purpose, 119 honey samples were collected during the harvesting period 2011 from 14 different regions in Greece known to produce unifloral honey of good quality. Physico-chemical analysis included the identification and semi quantification of fifty five volatile compounds performed by Headspace Solid Phase Microextraction coupled to gas chromatography/mass spectroscopy and the determination of conventional quality parameters such as pH, free, lactonic, total acidity, electrical conductivity, moisture, ash, lactonic/free acidity ratio and colour parameters L, a, b. Results showed that using 40 diverse variables (30 volatile compounds of different classes and 10 physico-chemical parameters) the honey samples were satisfactorily classified according to botanical origin using volatile compounds (84.0% correct prediction), physicochemical parameters (97.5% correct prediction), and the combination of both (95.8% correct prediction) indicating that multi element analysis comprises a powerful tool for honey discrimination purposes. Copyright © 2014 Elsevier Ltd. All rights reserved.

  6. A Methodology for Conducting Integrative Mixed Methods Research and Data Analyses

    Science.gov (United States)

    Castro, Felipe González; Kellison, Joshua G.; Boyd, Stephen J.; Kopak, Albert

    2011-01-01

    Mixed methods research has gained visibility within the last few years, although limitations persist regarding the scientific caliber of certain mixed methods research designs and methods. The need exists for rigorous mixed methods designs that integrate various data analytic procedures for a seamless transfer of evidence across qualitative and quantitative modalities. Such designs can offer the strength of confirmatory results drawn from quantitative multivariate analyses, along with “deep structure” explanatory descriptions as drawn from qualitative analyses. This article presents evidence generated from over a decade of pilot research in developing an integrative mixed methods methodology. It presents a conceptual framework and methodological and data analytic procedures for conducting mixed methods research studies, and it also presents illustrative examples from the authors' ongoing integrative mixed methods research studies. PMID:22167325

  7. Morphological and chemical analyses of Eriocauli Flos sold in Taiwan markets

    Directory of Open Access Journals (Sweden)

    I-Jung Lee

    2017-10-01

    Full Text Available Eriocauli Flos (Gujingcao; EF, the dried capitulum with the peduncle of Eriocaulon buergerianum Koern. (Eriocaulaceae, is a Chinese herbal medicine for treating eye diseases and inflammation. However, several species of the Eriocaulon genus are used as substitutes in different areas. To examine the species of EF used in Taiwan and to establish the quality control platform, morphological and chemical analyses have been performed. Ten major compounds, including apigenin (7 and its 7-O-β-D-glucopyranoside (1 and 7-O-(6-O-E-coumaroyl-β-D-glucopyranoside (6, hispidulin (8 and its 7-O-β-D-glucopyranoside (2 and 7-O-(6-O-E-coumaroyl-β-D-glucopyranoside (5, jaceosidin (9 and its 7-O-β-D-glucopyranoside (3, and toralactone (10 and its 9-O-β-D-glucopyranosyl(1→6-β-D-glucopyranoside (4, were isolated and identified from commercially available EF. Morphological investigation showed that two kinds of EFs and most of the EFs sold in Taiwan herbal markets are capitulum without the peduncle. A simultaneous high performance liquid chromatography and ultra performance liquid chromatography analyses of multiple components (1–10 in commercially available EFs, collected from different areas of Taiwan, was conducted. Results showed wide variations in morphology and chemical profiles between capitulum with and without the peduncle. In comparison with an authentic E. buergerianum, we found not only the morphology but also the chemical profile was different from both collected samples. In terms of the morphological examination, the samples without peduncle are closer to the authentic one. To ensure the correct EF materia medica is used in Taiwan so as to guarantee their therapeutic efficacy in clinical practice, further monitoring is necessary.

  8. Development of the Exams Data Analysis Spreadsheet as a Tool to Help Instructors Conduct Customizable Analyses of Student ACS Exam Data

    Science.gov (United States)

    Brandriet, Alexandra; Holme, Thomas

    2015-01-01

    The American Chemical Society Examinations Institute (ACS-EI) has recently developed the Exams Data Analysis Spread (EDAS) as a tool to help instructors conduct customizable analyses of their student data from ACS exams. The EDAS calculations allow instructors to analyze their students' performances both at the total score and individual item…

  9. Conducting meta-analyses of HIV prevention literatures from a theory-testing perspective.

    Science.gov (United States)

    Marsh, K L; Johnson, B T; Carey, M P

    2001-09-01

    Using illustrations from HIV prevention research, the current article advocates approaching meta-analysis as a theory-testing scientific method rather than as merely a set of rules for quantitative analysis. Like other scientific methods, meta-analysis has central concerns with internal, external, and construct validity. The focus of a meta-analysis should only rarely be merely describing the effects of health promotion, but rather should be on understanding and explaining phenomena and the processes underlying them. The methodological decisions meta-analysts make in conducting reviews should be guided by a consideration of the underlying goals of the review (e.g., simply effect size estimation or, preferably theory testing). From the advocated perspective that a health behavior meta-analyst should test theory, the authors present a number of issues to be considered during the conduct of meta-analyses.

  10. Fully coupled heat conduction and deformation analyses of nonlinear viscoelastic composites

    KAUST Repository

    Khan, Kamran

    2012-05-01

    This study presents an integrated micromechanical model-finite element framework for analyzing coupled heat conduction and deformations of particle-reinforced composite structures. A simplified micromechanical model consisting of four sub-cells, i.e., one particle and three matrix sub-cells is formulated to obtain the effective thermomechanical properties and micro-macro field variables due to coupled heat conduction and nonlinear thermoviscoelastic deformation of a particulate composite that takes into account the dissipation of energy from the viscoelastic constituents. A time integration algorithm for simultaneously solving the equations that govern heat conduction and thermoviscoelastic deformations of isotropic homogeneous materials is developed. The algorithm is then integrated to the proposed micromechanical model. A significant temperature generation due to the dissipation effect in the viscoelastic matrix was observed when the composite body is subjected to cyclic mechanical loadings. Heat conduction due to the dissipation of the energy cannot be ignored in predicting the factual temperature and deformation fields within the composite structure, subjected to cyclic loading for a long period. A higher creep resistant matrix material or adding elastic particles can lower the temperature generation. Our analyses suggest that using particulate composites and functionally graded materials can reduce the heat generation due to energy dissipation. © 2012 Elsevier Ltd.

  11. PETROS - Worldwide Databank of Major Element Chemical Analyses of Igneous Rocks

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — PETROS is a worldwide data bank of major element chemical analyses of igneous rocks compiled for research and teaching purposes by Dr. Felix Mutschler and Staff at...

  12. Electrical conductivities and chemical stabilities of mixed conducting pyrochlores for SOFC applications

    DEFF Research Database (Denmark)

    Holtappels, P.; Poulsen, F.W.; Mogensen, Mogens Bjerg

    2000-01-01

    Pyrochlores with praseodymium as the A-site cation and zirconium, tin, cerium and manganese cations on the B-site were prepared in air and their electrical conductivities were investigated as a function of oxygen partial pressure and temperature. Pure Pr2Zr2O7+/-delta as well as samples modified...

  13. Chemical analyses of rocks, minerals, and detritus, Yucca Mountain--Preliminary report, special report No. 11

    International Nuclear Information System (INIS)

    Hill, C.A.; Livingston, D.E.

    1993-09-01

    This chemical analysis study is part of the research program of the Yucca Mountain Project intended to provide the State of Nevada with a detailed assessment of the geology and geochemistry of Yucca Mountain and adjacent regions. This report is preliminary in the sense that more chemical analyses may be needed in the future and also in the sense that these chemical analyses should be considered as a small part of a much larger geological data base. The interpretations discussed herein may be modified as that larger data base is examined and established. All of the chemical analyses performed to date are shown in Table 1. There are three parts to this table: (1) trace element analyses on rocks (limestone and tuff) and minerals (calcite/opal), (2) rare earth analyses on rocks (tuff) and minerals (calcite/opal), and (3) major element analyses + CO 2 on rocks (tuff) and detritus sand. In this report, for each of the three parts of the table, the data and its possible significance will be discussed first, then some overall conclusions will be made, and finally some recommendations for future work will be offered

  14. The Equipment of Czech Firefighters for the Detection and Field Analyses of Chemical Warfare Agents

    Directory of Open Access Journals (Sweden)

    Jana Krykorkova

    2014-05-01

    Full Text Available This paper describes the requirements for the devices of detection, chemical reconnaissance and field analyses of chemical warfare agents (CWA and divides them into simple devices of detection, universal detectors, selective analyzers, multi-component analyzers and mobile laboratories. It also describes the devices of detection available within the Fire and Rescue Service of the Czech Republic (FRS CR and compares them with some prospective trends of further development.

  15. Nanoscale fabrication and characterization of chemically modified silicon surfaces using conductive atomic force microscopy in liquids

    Science.gov (United States)

    Kinser, Christopher Reagan

    This dissertation examines the modification and characterization of hydrogen-terminated silicon surfaces in organic liquids. Conductive atomic force microscope (cAFM) lithography is used to fabricate structures with sub-100 nm line width on H:Si(111) in n-alkanes, 1-alkenes, and 1-alkanes. Nanopatterning is accomplished by applying a positive (n-alkanes and 1-alkenes) or a negative (1-alkanes) voltage pulse to the silicon substrate with the cAFM tip connected to ground. The chemical and kinetic behavior of the patterned features is characterized using AFM, lateral force microscopy, time-of-flight secondary ion mass spectroscopy (TOF SIMS), and chemical etching. Features patterned in hexadecane, 1-octadecene, and undecylenic acid methyl ester exhibited chemical and kinetic behavior consistent with AFM field induced oxidation. The oxide features are formed due to capillary condensation of a water meniscus at the AFM tip-sample junction. A space-charge limited growth model is proposed to explain the observed growth kinetics. Surface modifications produced in the presence of neat 1-dodecyne and 1-octadecyne exhibited a reduced lateral force compared to the background H:Si(111) substrate and were resistant to a hydrofluoric acid etch, characteristics which indicate that the patterned features are not due to field induced oxidation and which are consistent with the presence of the methyl-terminated 1-alkyne bound directly to the silicon surface through silicon-carbon bonds. In addition to the cAFM patterned surfaces, full monolayers of undecylenic acid methyl ester (SAM-1) and undec-10-enoic acid 2-bromoethyl ester (SAM-2) were grown on H:Si(111) substrates using ultraviolet light. The structure and chemistry of the monolayers were characterized using AFM, TOF SIMS, X-ray photoelectron spectroscopy (XPS), X-ray reflectivity (XRR), X-ray standing waves (XSW), and X-ray fluorescence (XRF). These combined analyses provide evidence that SAM-1 and SAM-2 form dense monolayers

  16. Evaluation of Pre- and Post- Redevelopment Groundwater Chemical Analyses from LM Monitoring Wells

    International Nuclear Information System (INIS)

    Kamp, Susan; Dayvault, Jalena

    2016-01-01

    This report documents the efforts and analyses conducted for the Applied Studies and Technology (AS&T) Ancillary Work Plan (AWP) project titled Evaluation of Pre- and Post- Redevelopment Groundwater Sample Laboratory Analyses from Selected LM Groundwater Monitoring Wells. This effort entailed compiling an inventory of nearly 500 previous well redevelopment events at 16 U.S. Department of Energy Office of Legacy Management (LM) sites, searching the literature for impacts of well redevelopment on groundwater sample quality, and-the focus of this report-evaluating the impacts of well redevelopment on field measurements and sample analytical results. Study Catalyst Monitoring well redevelopment, the surging or high-volume pumping of a well to loosen and remove accumulated sediment and biological build-up from a well, is considered an element of monitoring well maintenance that is implemented periodically during the lifetime of the well to mitigate its gradual deterioration. Well redevelopment has been conducted fairly routinely at a few LM sites in the western United States (e.g., the Grand Junction office site and the Gunnison processing site in Colorado), but at most other sites in this region it is not a routine practice. Also, until recently (2014-2015), there had been no specific criteria for implementing well redevelopment, and documentation of redevelopment events has been inconsistent. A catalyst for this evaluation was the self-identification of these inconsistencies by the Legacy Management Support contractor. As a result, in early 2015 Environmental Monitoring Operations (EMO) staff began collecting and documenting additional field measurements during well redevelopment events. In late 2015, AS&T staff undertook an independent internal evaluation of EMO's well redevelopment records and corresponding pre- and post-well-redevelopment groundwater analytical results. Study Findings Although literature discussions parallel the prevailing industry

  17. Evaluation of Pre- and Post- Redevelopment Groundwater Chemical Analyses from LM Monitoring Wells

    Energy Technology Data Exchange (ETDEWEB)

    Kamp, Susan [Navarro Reserch and Engineering, Oak Ridge, TN (United States); Dayvault, Jalena [US Department of Energy, Washington, DC (United States). Office of Legacy Management

    2016-05-01

    This report documents the efforts and analyses conducted for the Applied Studies and Technology (AS&T) Ancillary Work Plan (AWP) project titled Evaluation of Pre- and Post- Redevelopment Groundwater Sample Laboratory Analyses from Selected LM Groundwater Monitoring Wells. This effort entailed compiling an inventory of nearly 500 previous well redevelopment events at 16 U.S. Department of Energy Office of Legacy Management (LM) sites, searching the literature for impacts of well redevelopment on groundwater sample quality, and—the focus of this report—evaluating the impacts of well redevelopment on field measurements and sample analytical results. Study Catalyst Monitoring well redevelopment, the surging or high-volume pumping of a well to loosen and remove accumulated sediment and biological build-up from a well, is considered an element of monitoring well maintenance that is implemented periodically during the lifetime of the well to mitigate its gradual deterioration. Well redevelopment has been conducted fairly routinely at a few LM sites in the western United States (e.g., the Grand Junction office site and the Gunnison processing site in Colorado), but at most other sites in this region it is not a routine practice. Also, until recently (2014–2015), there had been no specific criteria for implementing well redevelopment, and documentation of redevelopment events has been inconsistent. A catalyst for this evaluation was the self-identification of these inconsistencies by the Legacy Management Support contractor. As a result, in early 2015 Environmental Monitoring Operations (EMO) staff began collecting and documenting additional field measurements during well redevelopment events. In late 2015, AS&T staff undertook an independent internal evaluation of EMO's well redevelopment records and corresponding pre- and post-well-redevelopment groundwater analytical results. Study Findings Although literature discussions parallel the prevailing industry

  18. New Zealand guidelines for the collection of groundwater samples for chemical and isotopic analyses

    International Nuclear Information System (INIS)

    Rosen, M.R.; Cameron, S.G.; Reeves, R.R.; Taylor, C.B.

    1999-01-01

    Chemical and isotopic analyses of groundwater are important tools for differentiating between the natural composition and human-induced contaminants of groundwater. A comprehensive suite of inorganic water chemical analyses is necessary to characterise waters. The geology of New Zealand is diverse, so it is impractical to characterise a ''typical'' groundwater chemical composition. Each aquifer system should be evaluated individually because the major dissolved species contain useful information about the pathways of water through the soil zone into the aquifer. Analyses of major ions such as chloride, nitrate, potassium and sulphate often give indication of septic systems and agricultural contamination. The minor ions, while most are not considered contaminants, are often indicators of human activity. Iron and manganese are good indicators of Eh potential, which is an important control on the mobility of many heavy metals. The inexpensive inorganic chemical analytical suite should be used as a guide to advisability of more expensive contaminant testing. The purpose of this manual is to provide consistent groundwater sampling guidelines for use throughout New Zealand. Sinton's (1998) guide to groundwater sampling techniques provided a sound basis for the accurate collection of groundwater samples. However Sinton did not address sampling materials and techniques for the collection of samples for ultra trace component analysis or the collection of environmental isotope samples. These important aspects of groundwater sampling have been included in this updated manual. (author). 30 refs., 12 figs., 5 tabs., 1 appendix

  19. Study of the conductivity of a metallic tube by analysing the damped fall of a magnet

    International Nuclear Information System (INIS)

    Iniguez, J; Raposo, V; Hernandez-Lopez, A; Flores, A G; Zazo, M

    2004-01-01

    The fall of a magnet through a hollow conducting tube is described. Although this experiment is well known, a detailed treatment by means of a circuit analysis allows us to relate the conductivity of the tube to the characteristic parameters of the experiment

  20. Chemical analysis of minerals in granitic rocks by electron probe micro analyser

    International Nuclear Information System (INIS)

    Hiraoka, Yoshihiro

    1994-01-01

    The chemical compositions of minerals in a few granitic rocks were determined by electron probe micro analyser (EPMA). The accurate analytical data for standard feldspar groups were obtained by correcting the low analytical values of sodium and potassium that were arised from the damage in EPMA analysis. Using this method, feldspar groups and biotites in three granitic rocks gathered from Hiei, Hira and Kurama areas respectively, were analyzed. As the results, the local characteristics were observed in the kinds of feldspar groups and the chemical compositions of biotites that were contained in granitic rocks. (author)

  1. Chemical analyses of wasp-associated streptomyces bacteria reveal a prolific potential for natural products discovery

    DEFF Research Database (Denmark)

    Poulsen, Michael; Oh, Dong-Chan; Clardy, Jon

    2011-01-01

    and solitary Hymenoptera. Here we test this possibility by examining two species of solitary mud dauber wasps, Sceliphron caementarium and Chalybion californicum. We performed enrichment isolations from 33 wasps and obtained more than 200 isolates of Streptomyces Actinobacteria. Chemical analyses of 15...... and antibacterial activity. The prevalence and anti-microbial properties of Actinobacteria associated with these two solitary wasp species suggest the potential role of these Streptomyces as antibiotic-producing symbionts, potentially helping defend their wasp hosts from pathogenic microbes. Finding...... phylogenetically diverse and chemically prolific Actinobacteria from solitary wasps suggests that insect-associated Actinobacteria can provide a valuable source of novel natural products of pharmaceutical interest....

  2. Analyses on the U-Mo/Al Chemical Interaction and the Effects of Diffusion Barrier Coatings

    Energy Technology Data Exchange (ETDEWEB)

    Ryu, Ho Jin; Kim, Woo Jeong; Cho, Woo Hyung; Jeong, Yong Jin; Lee, Yoon Sang; Park, Jong Man; Kim, Chang Kyu [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2012-05-15

    While many HEU-fueled research reactors have been converted by adopting LEU U{sub 3}Si{sub 2} fuel in harmony with the Reduced Enrichment for Research and Test Reactors (RERTR) program, some high performance research reactors still need the development of advanced fuels with higher uranium densities. Currently, gamma-phase U-Mo alloys are considered promising candidates to be used as high uranium density fuel for the high performance reactors. For the production of UMo alloy powder, the centrifugal atomization technology developed by KAERI has been considered the most promising way because of high yield production and excellent powder quality when compared with other possible methods such as grinding, machining or hydriding-dehydriding. However, severe pore formation associated with an extensive interaction between the U-Mo and Al matrix, although the irradiation performance of U-Mo itself showed most stable, delay the fuel qualification of UMo fuel for high performance research reactors. Because the reaction products, i.e. uranium aluminides (UAlx), is less dense than the mixed reactants, the volume of the fuel meat increases after formation of interaction layer(IL). In addition to the impact on the swelling performance, the reaction layers between the U-Mo and Al matrix induces a degradation of the thermal conductivities of the U-Mo/Al dispersion fuels. The chemical interaction between the U-Mo and Al matrix are analyzed in this study to find remedies to reduce the growth of the interaction layers during irradiation. In addition, various coating technologies for the formation of diffusion barriers on U-Mo particles are proposed as a result of the analyses

  3. Fully coupled heat conduction and deformation analyses of nonlinear viscoelastic composites

    KAUST Repository

    Khan, Kamran; Muliana, Anastasia Hanifah

    2012-01-01

    This study presents an integrated micromechanical model-finite element framework for analyzing coupled heat conduction and deformations of particle-reinforced composite structures. A simplified micromechanical model consisting of four sub-cells, i

  4. Quality control and conduct of genome-wide association meta-analyses

    DEFF Research Database (Denmark)

    Winkler, Thomas W; Day, Felix R; Croteau-Chonka, Damien C

    2014-01-01

    Rigorous organization and quality control (QC) are necessary to facilitate successful genome-wide association meta-analyses (GWAMAs) of statistics aggregated across multiple genome-wide association studies. This protocol provides guidelines for (i) organizational aspects of GWAMAs, and for (ii) QC...

  5. Thermal conductivity degradation analyses of LWR MOX fuel by the quasi-two phase material model

    International Nuclear Information System (INIS)

    Kosaka, Yuji; Kurematsu, Shigeru; Kitagawa, Takaaki; Suzuki, Akihiro; Terai, Takayuki

    2012-01-01

    The temperature measurements of mixed oxide (MOX) and UO 2 fuels during irradiation suggested that the thermal conductivity degradation rate of the MOX fuel with burnup should be slower than that of the UO 2 fuel. In order to explain the difference of the degradation rates, the quasi-two phase material model is proposed to assess the thermal conductivity degradation of the MIMAS MOX fuel, which takes into account the Pu agglomerate distributions in the MOX fuel matrix as fabricated. As a result, the quasi-two phase model calculation shows the gradual increase of the difference with burnup and may expect more than 10% higher thermal conductivity values around 75 GWd/t. While these results are not fully suitable for thermal conductivity degradation models implemented by some industrial fuel manufacturers, they are consistent with the results from the irradiation tests and indicate that the inhomogeneity of Pu content in the MOX fuel can be one of the major reasons for the moderation of the thermal conductivity degradation of the MOX fuel. (author)

  6. [Analyses of the clinical characteristics of unilateral conductive hearing loss with intact tympanic membrane].

    Science.gov (United States)

    Tang, Chaoying; Zhang, Jishuai; Han, Weiju; Shen, Weidong; Liu, Jun; Hou, Zhaohui; Dai, Pu; Yang, Shiming; Han, Dongyi

    2016-05-01

    To analyze the clinical characteristics of unilateral conductive hearing loss with intact tympanic membrane, and summarize the key diagnostic points, differential diagnosis and observe the effects of surgical treatment. We reviewed data from 82 patients with unilateral conductive hearing loss with intact tympanic membranes who accepted the exploratory tympanotomy from April 2011 to September 2013. There were 41 males and 41 females, aged from 7 to 66( averaged 26.5±13.7)years, with a history of one month to 50 years. The history, clinical symptoms, audiological evaluation, high resolution temporal bone CT, the results of surgical exploration and hearing reconstruction were analyzed. The exploratory tympanotomy revealed 43 cases of congenital middle ear malformations (52.4%), 22 cases of otosclerosis (26.8%), eight cases of congenital cholesteatoma (9.8%), six cases of trauma induced conductive hearing loss (7.3%), three cases of congenital ossicular malformations with congenital cholesteatoma (3.7%). Progressive hearing loss was common in patients with otosclerosis and congenital cholesteatoma, and patients with congenital middle ear malformations described their hearing loss since childhood. High resolution temporal bone CT of congenital middle ear malformation, trauma induced conductive hearing loss, congenital cholesteatoma diagnosis rate was 40.0%, 50.0%, and 83.3% respectively. The preoperative air-conductive threshold of patients with absence of the oval window were increased to (66.9±1.1)dBHL, the preoperative bone-conductive threshold achieved (28.3±10.4)dBHL at 2 000 Hz. While patients with stapes fixation and that with ossicular chain discontinuity were (27.2±9.7)dBHL and (17.8±8.8)dBHL(P=0.000)respectively. Through the tympanic exploration with endaural incision under the microscope, different hearing reconstruction were applied according to different lesions. After the operation, the hearing level of 52 patients with return visit were improved, the

  7. Estimation of effective block conductivities based on discrete network analyses using data from the Aespoe site

    International Nuclear Information System (INIS)

    La Pointe, P.R.; Wallmann, P.; Follin, S.

    1995-09-01

    Numerical continuum codes may be used for assessing the role of regional groundwater flow in far-field safety analyses of a nuclear waste repository at depth. The focus of this project is to develop and evaluate one method based on Discrete Fracture Network (DFN) models to estimate block-scale permeability values for continuum codes. Data from the Aespoe HRL and surrounding area are used. 57 refs, 76 figs, 15 tabs

  8. Effect of chemical composition on the electrical conductivity of gneiss at high temperatures and pressures

    Directory of Open Access Journals (Sweden)

    L. Dai

    2018-03-01

    Full Text Available The electrical conductivity of gneiss samples with different chemical compositions (WA = Na2O + K2O + CaO  =  7.12, 7.27 and 7.64 % weight percent was measured using a complex impedance spectroscopic technique at 623–1073 K and 1.5 GPa and a frequency range of 10−1 to 106 Hz. Simultaneously, a pressure effect on the electrical conductivity was also determined for the WA = 7.12 % gneiss. The results indicated that the gneiss conductivities markedly increase with total alkali and calcium ion content. The sample conductivity and temperature conform to an Arrhenius relationship within a certain temperature range. The influence of pressure on gneiss conductivity is weaker than temperature, although conductivity still increases with pressure. According to various ranges of activation enthalpy (0.35–0.52 and 0.76–0.87 eV at 1.5 GPa, two main conduction mechanisms are suggested that dominate the electrical conductivity of gneiss: impurity conduction in the lower-temperature region and ionic conduction (charge carriers are K+, Na+ and Ca2+ in the higher-temperature region. The electrical conductivity of gneiss with various chemical compositions cannot be used to interpret the high conductivity anomalies in the Dabie–Sulu ultrahigh-pressure metamorphic belt. However, the conductivity–depth profiles for gneiss may provide an important constraint on the interpretation of field magnetotelluric conductivity results in the regional metamorphic belt.

  9. Relativistic thermodynamics of irreversible processes I. Heat conduction, diffusion, viscous flow and chemical reactions; formal part

    NARCIS (Netherlands)

    Kluitenberg, G.A.; Groot, S.R. de; Mazur, P.

    1953-01-01

    The relativistic thermodynamics of irreversible processes is developed for an isotropic mixture in which heat conduction, diffusion, viscous flow, chemical reactions and their cross-phenomena may occur. The four-vectors, representing the relative flows of matter, are defined in such a way that, in

  10. Conducting Polymers in the Fields of Energy, Environmental Remediation, and Chemical-Chiral Sensors.

    Science.gov (United States)

    Ibanez, Jorge G; Rincón, Marina E; Gutierrez-Granados, Silvia; Chahma, M'hamed; Jaramillo-Quintero, Oscar A; Frontana-Uribe, Bernardo A

    2018-05-09

    Conducting polymers (CPs), thanks to their unique properties, structures made on-demand, new composite mixtures, and possibility of deposit on a surface by chemical, physical, or electrochemical methodologies, have shown in the last years a renaissance and have been widely used in important fields of chemistry and materials science. Due to the extent of the literature on CPs, this review, after a concise introduction about the interrelationship between electrochemistry and conducting polymers, is focused exclusively on the following applications: energy (energy storage devices and solar cells), use in environmental remediation (anion and cation trapping, electrocatalytic reduction/oxidation of pollutants on CP based electrodes, and adsorption of pollutants) and finally electroanalysis as chemical sensors in solution, gas phase, and chiral molecules. This review is expected to be comprehensive, authoritative, and useful to the chemical community interested in CPs and their applications.

  11. Influence of Electrical Conductivity, Days in Milk and Parity on Milk Production and Chemical Composition

    Directory of Open Access Journals (Sweden)

    Radu Ionel Neamț

    2016-10-01

    Full Text Available The aim of study was to assess milk production and chemical composition during the first 100 days of lactation, under the influence of electrical conductivity, parity and days in milk. Study was conducted at Research and Development Station for Bovine Arad, on 66 Romanian Spotted cows (20 primiparous, 46 multiparous. Significantly higher values (p≤0.017 of electrical conductivity were recorded for primiparous (10.15±0.09 mS/cm compared with multiparous (8.79±0.15 mS/cm. During the first 30 DIM electrical conductivity was higher (9.7±0.12 mS/cm than for 31 to 60 DIM (9.04±0.12 mS/cm; p≤0.001 and for 61 to 100 DIM (8.17±0.11 mS/cm, p≤0.001. Multifactorial regression model applied highlights significant influence of month of calving (p≤0.001 and DIM (p≤0.034 on the electrical conductivity, while parity had no influence (p>0.36. Medium and negative correlations were calculated between electrical conductivity and some chemical components (fat R=-0.15, protein R=-0.13, while to milk production correlation was positive (R=0.12. No significant correlations were obtained according to lactose content (R=-0.013. Dynamics of milk production and chemical composition have been significantly influenced by month of calving (p≤0.001, DIM (p≤0.001 and parity (p≤0.002. This study found no significant influence of milk electrical conductivity on milk production or chemical composition (p>0.59.

  12. Conducting requirements analyses for research using routinely collected health data: a model driven approach.

    Science.gov (United States)

    de Lusignan, Simon; Cashman, Josephine; Poh, Norman; Michalakidis, Georgios; Mason, Aaron; Desombre, Terry; Krause, Paul

    2012-01-01

    Medical research increasingly requires the linkage of data from different sources. Conducting a requirements analysis for a new application is an established part of software engineering, but rarely reported in the biomedical literature; and no generic approaches have been published as to how to link heterogeneous health data. Literature review, followed by a consensus process to define how requirements for research, using, multiple data sources might be modeled. We have developed a requirements analysis: i-ScheDULEs - The first components of the modeling process are indexing and create a rich picture of the research study. Secondly, we developed a series of reference models of progressive complexity: Data flow diagrams (DFD) to define data requirements; unified modeling language (UML) use case diagrams to capture study specific and governance requirements; and finally, business process models, using business process modeling notation (BPMN). These requirements and their associated models should become part of research study protocols.

  13. Carbon speciation in ash, residual waste and contaminated soil by thermal and chemical analyses.

    Science.gov (United States)

    Kumpiene, Jurate; Robinson, Ryan; Brännvall, Evelina; Nordmark, Désirée; Bjurström, Henrik; Andreas, Lale; Lagerkvist, Anders; Ecke, Holger

    2011-01-01

    Carbon in waste can occur as inorganic (IC), organic (OC) and elemental carbon (EC) each having distinct chemical properties and possible environmental effects. In this study, carbon speciation was performed using thermogravimetric analysis (TGA), chemical degradation tests and the standard total organic carbon (TOC) measurement procedures in three types of waste materials (bottom ash, residual waste and contaminated soil). Over 50% of the total carbon (TC) in all studied materials (72% in ash and residual waste, and 59% in soil) was biologically non-reactive or EC as determined by thermogravimetric analyses. The speciation of TOC by chemical degradation also showed a presence of a non-degradable C fraction in all materials (60% of TOC in ash, 30% in residual waste and 13% in soil), though in smaller amounts than those determined by TGA. In principle, chemical degradation method can give an indication of the presence of potentially inert C in various waste materials, while TGA is a more precise technique for C speciation, given that waste-specific method adjustments are made. The standard TOC measurement yields exaggerated estimates of organic carbon and may therefore overestimate the potential environmental impacts (e.g. landfill gas generation) of waste materials in a landfill environment. Copyright © 2010 Elsevier Ltd. All rights reserved.

  14. Fully coupled heat conduction and deformation analyses of visco-elastic solids

    KAUST Repository

    Khan, Kamran

    2012-04-21

    Visco-elastic materials are known for their capability of dissipating energy. This energy is converted into heat and thus changes the temperature of the materials. In addition to the dissipation effect, an external thermal stimulus can also alter the temperature in a viscoelastic body. The rate of stress relaxation (or the rate of creep) and the mechanical and physical properties of visco-elastic materials, such as polymers, vary with temperature. This study aims at understanding the effect of coupling between the thermal and mechanical response that is attributed to the dissipation of energy, heat conduction, and temperature-dependent material parameters on the overall response of visco-elastic solids. The non-linearly viscoelastic constitutive model proposed by Schapery (Further development of a thermodynamic constitutive theory: stress formulation, 1969,Mech. Time-Depend. Mater. 1:209-240, 1997) is used and modified to incorporate temperature- and stress-dependent material properties. This study also formulates a non-linear energy equation along with a dissipation function based on the Gibbs potential of Schapery (Mech. Time-Depend. Mater. 1:209-240, 1997). A numerical algorithm is formulated for analyzing a fully coupled thermo-visco-elastic response and implemented it in a general finite-element (FE) code. The non-linear stress- and temperature-dependent material parameters are found to have significant effects on the coupled thermo-visco-elastic response of polymers considered in this study. In order to obtain a realistic temperature field within the polymer visco-elastic bodies undergoing a non-uniform heat generation, the role of heat conduction cannot be ignored. © Springer Science+Business Media, B. V. 2012.

  15. General-purpose chemical analyzer for on-line analyses of radioactive solutions

    International Nuclear Information System (INIS)

    Spencer, W.A.; Kronberg, J.W.

    1983-01-01

    An automated analyzer is being developed to perform analytical measurements on radioactive solutions on-line in a hostile environment. This General Purpose Chemical Analyzer (GPCA) samples a process stream, adds reagents, measures solution absorbances or electrode potentials, and automatically calculates the results. The use of modular components, under microprocessor control, permits a single analyzer design to carry out many types of analyses. This paper discusses the more important design criteria for the GPCA, and describes the equipment being tested in a prototype unit

  16. Treatment of spices with ionizing radiation - chemical, organoleptical, microbiological and toxicological analyses. Pt. 2

    International Nuclear Information System (INIS)

    Schuettler, C.; Boegl, W.

    1984-09-01

    In the present second part of a study of the relevant literature the results of tests on 14 radiation treated spices and 2 radiation treated spice-mixtures were evaluated. The tests in this part contain mainly toxicological but also chemical and sensorial analyses. Most of the spices were treated with gamma radiation from cobalt-60 sources with doses between 80 Gy and 60 kGy. This part contains a cumulated subject index for part 1 and part 2. (orig./AJ) [de

  17. Citation Discovery Tools for Conducting Adaptive Meta-analyses to Update Systematic Reviews.

    Science.gov (United States)

    Bae, Jong-Myon; Kim, Eun Hee

    2016-03-01

    The systematic review (SR) is a research methodology that aims to synthesize related evidence. Updating previously conducted SRs is necessary when new evidence has been produced, but no consensus has yet emerged on the appropriate update methodology. The authors have developed a new SR update method called 'adaptive meta-analysis' (AMA) using the 'cited by', 'similar articles', and 'related articles' citation discovery tools in the PubMed and Scopus databases. This study evaluates the usefulness of these citation discovery tools for updating SRs. Lists were constructed by applying the citation discovery tools in the two databases to the articles analyzed by a published SR. The degree of overlap between the lists and distribution of excluded results were evaluated. The articles ultimately selected for the SR update meta-analysis were found in the lists obtained from the 'cited by' and 'similar' tools in PubMed. Most of the selected articles appeared in both the 'cited by' lists in Scopus and PubMed. The Scopus 'related' tool did not identify the appropriate articles. The AMA, which involves using both citation discovery tools in PubMed, and optionally, the 'related' tool in Scopus, was found to be useful for updating an SR.

  18. The French National Authority for Health (HAS) Guidelines for Conducting Budget Impact Analyses (BIA).

    Science.gov (United States)

    Ghabri, Salah; Autin, Erwan; Poullié, Anne-Isabelle; Josselin, Jean Michel

    2018-04-01

    Budget impact analysis (BIA) provides short- and medium-term estimates on changes in budgets and health outcomes resulting from the adoption of new health interventions. The purpose of this study is to present the newly developed French National Authority for Health (HAS) guidelines on budget impact analysis as follows: process, literature review, recommendations and comparisons with other guidelines. The development process of the HAS guidelines included a literature review (search dates: January 2000 to June 2016), a retrospective investigation of BIA previously submitted to HAS, a public consultation, international expert reviews and approval from the HAS Board and the Economic and Public Health Evaluation Committee of HAS. Documents identified in the literature review included 12 national guidelines, 5 recommendations for good practices developed by national and international society of health economics and 14 methodological publications including recommendations for conducting BIA. Based on its research findings, HAS developed its first BIA guidelines, which include recommendations on the following topics: BIA definition, perspective, populations, time horizon, compared scenarios, budget impact models, costing, discounting, choice of clinical data, reporting of results and uncertainty exploration. It is expected that the HAS BIA guidelines will enhance the usefulness, quality and transparency of BIA submitted by drug manufacturers to HAS. BIA is becoming an essential part of a comprehensive economic assessment of healthcare interventions in France, which also includes cost-effectiveness analysis and equity of access to healthcare.

  19. FMEA and FTA Analyses of the Adhesive Joining Process using Electrically Conductive Adhesives

    Directory of Open Access Journals (Sweden)

    E. Povolotskaya

    2012-01-01

    Full Text Available This paper introduces a formulation of appropriate risk estimation methods that can be used for improving of processes in the electronics area. Two risk assessment methods have been chosen with regard to the specifics of adhesive joining based on electrically conductive adhesives. The paper provides a combination of a failure mode and effect analysis (FMEA and fault tree analysis (FTA for optimizing of the joining process. Typical features and failures of the process are identified. Critical operations are found and actions for avoiding failures in these actions are proposed. A fault treehas been applied to the process in order to get more precise information about the steps and operations in the process, and the relations between these operations. The fault tree identifies potential failures of the process. Then the effects of the failures have been estimated by the failure mode and effect analysis method. All major differences between failure mode and effect analysis and fault tree analysis are defined and there is a discussion about how to use the two techniquescomplement each other and achieve more efficient results.

  20. Evaluation Of Plutonium Oxide Destructive Chemical Analyses For Validity Of Original 3013 Container Binning

    International Nuclear Information System (INIS)

    Mcclard, J.; Kessinger, G.

    2010-01-01

    The surveillance program for 3013 containers is based, in part, on the separation of containers into various bins related to potential container failure mechanisms. The containers are assigned to bins based on moisture content and pre-storage estimates of content chemistry. While moisture content is measured during the packaging of each container, chemistry estimates are made by using a combination of process knowledge, packaging data and prompt gamma analyses to establish the moisture and chloride/fluoride content of the materials. Packages with high moisture and chloride/fluoride contents receive more detailed surveillances than packages with less chloride/fluoride and/or moisture. Moisture verification measurements and chemical analyses performed during the surveillance program provided an opportunity to validate the binning process. Validation results demonstrated that the binning effort was generally successful in placing the containers in the appropriate bin for surveillance and analysis.

  1. Guidelines for conducting pharmaceutical budget impact analyses for submission to public drug plans in Canada.

    Science.gov (United States)

    Marshall, Deborah A; Douglas, Patrick R; Drummond, Michael F; Torrance, George W; Macleod, Stuart; Manti, Orlando; Cheruvu, Lokanadha; Corvari, Ron

    2008-01-01

    Until now, there has been no standardized method of performing and presenting budget impact analyses (BIAs) in Canada. Nevertheless, most drug plan managers have been requiring this economic data to inform drug reimbursement decisions. This paper describes the process used to develop the Canadian BIA Guidelines; describes the Guidelines themselves, including the model template; and compares this guidance with other guidance on BIAs. The intended audience includes those who develop, submit or use BIA models, and drug plan managers who evaluate BIA submissions. The Patented Medicine Prices Review Board (PMPRB) initiated the development of the Canadian BIA Guidelines on behalf of the National Prescription Drug Utilisation Information System (NPDUIS). The findings and recommendations from a needs assessment with respect to BIA submissions were reviewed to inform guideline development. In addition, a literature review was performed to identify existing BIA guidance. The detailed guidance was developed on this basis, and with the input of the NPDUIS Advisory Committee, including drug plan managers from multiple provinces in Canada and a representative from the Canadian Agency for Drugs and Technologies in Health. A Microsoft Excel-based interactive model template was designed to support BIA model development. Input regarding the guidelines and model template was sought from each NPDUIS Advisory Committee member to ensure compatibility with existing drug plan needs. Decisions were made by consensus through multiple rounds of review and discussion. Finally, BIA guidance in Canadian provinces and other countries were compared on the basis of multiple criteria. The BIA guidelines consist of three major sections: Analytic Framework, Inputs and Data Sources, and Reporting Format. The Analytic Framework section contains a discussion of nine general issues surrounding BIAs (model design, analytic perspective, time horizon, target population, costing, scenarios to be compared

  2. Chemical analyses for selected wells in San Joaquin County and part of Contra Costa County, California

    Science.gov (United States)

    Keeter, Gail L.

    1980-01-01

    The study area of this report includes the eastern valley area of Contra Costa County and all of San Joaquin County, an area of approximately 1,600 square miles in the northern part of the San Joaquin Valley, Calif. Between December 1977 and December 1978, 1,489 wells were selectively canvassed. During May and June in 1978 and 1979, water samples were collected for chemical analysis from 321 of these wells. Field determinations of alkalinity, conductance, pH, and temperature were made, and individual constituents were analyzed. This report is the fourth in a series of baseline data reports on wells in the Sacramento and San Joaquin Valleys. (USGS)

  3. Chemically stable Dy–Y double substituted barium zirconate with high proton conductivity and improved sinterability

    Energy Technology Data Exchange (ETDEWEB)

    Paydar, M.H., E-mail: paaydar@shirazu.ac.ir [Department of Materials Science and Engineering, School of Engineering, Shiraz University, Shiraz (Iran, Islamic Republic of); Nishimura, Ch. [Hydrogen Materials Unit, Environment and Energy Materials Division, National Institute for Materials Science, Tsukuba, Ibaraki (Japan); Kobayashi, K. [Advanced Ceramics Group, Materials Processing Unit, Advanced Key Technologies Division, National Institute for Materials Science, Tsukuba, Ibaraki (Japan)

    2015-10-05

    Highlights: • BaZr{sub (0.8−x)}Dy{sub x}Y{sub 0.2}O{sub 3−δ} (0 ⩽ x ⩽ 0.2) powders were synthesized by a wet chemical route. • The ability of the synthesized powders in uptaking water was determined. • Chemical stability of the synthesized powders was evaluated under in wet and CO{sub 2} atmosphere. • The conductivity of the sintered pellets was measured by AC impedance spectroscopy. • It was shown that Dy-doped BZY20 ceramic has excellent proton conductivity. • It was proved that Dy-doped BZY20 ceramic has good chemical stability. • It was concluded that Dy-doped BZY20 electrolyte can be considered as a promising electrolyte for solid oxide fuel cell applications. - Abstract: Novel proton conductors BaZr{sub (0.8−x)}Dy{sub x}Y{sub 0.2}O{sub 3−δ} (BZ{sub 0.8−x}D{sub x}Y20, 0 ⩽ x ⩽ 0.2) with high proton conductivity, chemical stability and improved sinterability are developed by partially substituting the Zr site of the 20 mol% Y-doped barium zirconate (BZY20) with Dy. A modified Pechini method was applied to synthesize the BZ{sub 0.8−x}D{sub x}Y20 powders. The X-ray diffraction patterns of the well-calcined powders indicated that the specimens with 0 ⩽ x ⩽ 0.2 possessed a single-phase of cubic perovskite-type oxides. Stability tests under both CO{sub 2} and moist air atmospheres demonstrated that the excellent chemical stability of the base BZY20 material was not influenced by the introduction of Dy. High density pellets with larger grain sizes were obtained at temperatures lower than those commonly employed for the base Y-doped barium zirconate compound. The proton conductivities, measured in different oxidizing and reducing, dry and humidified atmospheres by impedance spectroscopy, were significantly influenced by the Dy amount. In overall, BaZr{sub (0.8−x)}Dy{sub x}Y{sub 0.2}O{sub 3−δ} solid solutions having Dy ∼ 5–10% showed excellent chemical stability and high conductivity (above 10{sup −2} S cm{sup −1} at

  4. Chemical Principles and Interference in the Electrical Conductance of Single Molecules

    DEFF Research Database (Denmark)

    Borges, Anders Christian

    , the conductance of molecules can vary orders of magnitude and the concept of interference is believed to play a major role in this. This thesis investigates the links between single molecule conductance, chemistry and interference effects in short organic molecules. It is investigated to which extent...... the conductance can be understood in terms of separate contributions and when the effects of interference are important. Links between chemical principles and constructive- and destructive interference effects are demonstrated using a combination of simple models, atomistic calculations and Scanning......-Tunneling Microscope Break-Junction experiments (STM-BJ). It is demonstrated that these links can be used to design molecules exhibiting surprising interference effects and to interpret and predict the trends in the characteristic conductance of single molecules without resorting to numerical computational methods...

  5. Reversible solid oxide fuel cells (R-SOFCs) with chemically stable proton-conducting oxides

    KAUST Repository

    Bi, Lei

    2015-07-01

    Proton-conducting oxides offer a promising way of lowering the working temperature of solid oxide cells to the intermediate temperate range (500 to 700. °C) due to their better ionic conductivity. In addition, the application of proton-conducting oxides in both solid oxide fuel cells (SOFCs) and sold oxide electrolysis cells (SOECs) provides unique advantages compared with the use of conventional oxygen-ion conducting conductors, including the formation of water at the air electrode site. Since the discovery of proton conduction in some oxides about 30. years ago, the development of proton-conducting oxides in SOFCs and SOECs (the reverse mode of SOFCs) has gained increased attention. This paper briefly summarizes the development in the recent years of R-SOFCs with proton-conducting electrolytes, focusing on discussing the importance of adopting chemically stable materials in both fuel cell and electrolysis modes. The development of electrode materials for proton-conducting R-SOFCs is also discussed. © 2015 Elsevier B.V.

  6. Thermal Conductivity of Moulding Sand with Chemical Binders, Attempts of its Increasing

    Directory of Open Access Journals (Sweden)

    Zych J.

    2015-04-01

    Full Text Available The investigation results of the thermal conductivity of the selected group of moulding sands with chemical binders, mainly organic, are presented in the hereby paper. Studies encompassed also moulding sands into which additions improving the thermal conductivity were introduced. Two testing methods were applied, i.e. investigations at a steady and unsteady temperature zone. For investigations at a steady temperature zone the new original experimental stand was designed and built, adapted also for testing moulding sands with binders undergoing destruction at relatively low temperatures.

  7. Flow of chemically reactive magneto Cross nanoliquid with temperature-dependent conductivity

    Science.gov (United States)

    Hayat, Tasawar; Ullah, Ikram; Waqas, Muhammad; Alsaedi, Ahmed

    2018-05-01

    Influence of temperature-dependent thermal conductivity on MHD flow of Cross nanoliquid bounded by a stretched sheet is explored. The combined feature of Brownian motion and thermophoresis in nanoliquid modeling is retained. In addition, the attributes of zero mass flux at sheet are imposed. First-order chemical reaction is retained. The resulting problems are numerically computed. Plots and tabulated values are presented and examined. It is figured out that larger thermophoretic diffusion and thermal conductivity significantly rise the thermal field, whereas opposite situation is seen for heat transfer rate.

  8. Poisoned Wine: Regulation, Chemical Analyses, and Spanish-French Trade in the 1930s.

    Science.gov (United States)

    Suay-Matallana, Ignacio; Guillem-Llobat, Ximo

    2018-04-16

    This paper describes the resources, scientific spaces, and experts involved in the study of a mass poisoning caused by the drinking of arsenic-contaminated wine exported from Spain to France in 1932. Local and international periodicals record the poisoning of 300 French sailors, and stressed the commercial implications of the case. We discuss the reports prepared by different experts (mainly physicians, agricultural engineers, and customs chemists). Their work was not limited to preparing technical publications or chemical analyses; they also actively defended the quality of their local wine, and played a major role in the discussions regarding the regulation of the international wine market in the 1930s, when new standards regarding the analysis of wine were being considered. Curiously, this well-publicised case of mass poisoning did not have any noticeable consequences in the international regulation of wine. This absence of subsequent regulatory action and the role of experts are central topics of the paper.

  9. Toxicity testing and chemical analyses of recycled fibre-based paper for food contact

    DEFF Research Database (Denmark)

    Binderup, Mona-Lise; Pedersen, Gitte Alsing; Vinggaard, Anne

    2002-01-01

    of different qualities as food-contact materials and to Perform a preliminary evaluation of their suitability from a safety point of view, and, second, to evaluate the use of different in vitro toxicity tests for screening of paper and board. Paper produced from three different categories of recycled fibres (B...... of the paper products were extracted with either 99% ethanol or water. Potential migrants in the extracts were identified and semiquantified by GC-1R-MS or GC-HRMS. In parallel to the chemical analyses, a battery of four different in vitro toxicity tests with different endpoints were applied to the same...... was less cytotoxic than the extracts prepared from paper made from recycled fibres, and extracts prepared from C was the most cytotoxic. None of the extracts showed mutagenic activity No conclusion about the oestrogenic activity could be made, because all extracts were cytotoxic to the test organism (yeast...

  10. Historical Weathering Based on Chemical Analyses of Two Spodosols in Southern Sweden

    International Nuclear Information System (INIS)

    Melkerud, Per-Arne; Bain, Derek C.; Olsson, Mats T.

    2003-01-01

    Chemical weathering losses were calculated for two conifer stands in relation to ongoing studies on liming effects and ash amendments on chemical status, soil solution chemistry and soil genesis. Weathering losses were based on elemental depletion trends in soil profiles since deglaciation and exposure to the weathering environment. Gradients in total geochemical composition were assumed to reflect alteration over time. Study sites were Horroed and Hassloev in southern Sweden. Both Horroed and Hassloev sites are located on sandy loamy Weichselian till at an altitude of 85 and 190 m a.s.l., respectively. Aliquots from volume determined samples from a number of soil levels were fused with lithium metaborate, dissolved in HNO 3 , and analysed by ICP - AES. Results indicated highest cumulative weathering losses at Hassloev. The weathering losses for the elements are in the following order:Si > Al > K > Na > Ca > MgTotal annual losses for Ca+Mg+K+Na, expressed in mmol c m -2 yr -1 , amounted to c. 28 and 58 at Horroed and Hassloev, respectively. Variations between study sites could not be explained by differences in bulk density, geochemistry or mineralogy. The accumulated weathering losses since deglaciation were larger in the uppermost 15 cm than in deeper B horizons for most elements studied

  11. Chemical analyses of wasp-associated streptomyces bacteria reveal a prolific potential for natural products discovery.

    Directory of Open Access Journals (Sweden)

    Michael Poulsen

    2011-02-01

    Full Text Available Identifying new sources for small molecule discovery is necessary to help mitigate the continuous emergence of antibiotic-resistance in pathogenic microbes. Recent studies indicate that one potentially rich source of novel natural products is Actinobacterial symbionts associated with social and solitary Hymenoptera. Here we test this possibility by examining two species of solitary mud dauber wasps, Sceliphron caementarium and Chalybion californicum. We performed enrichment isolations from 33 wasps and obtained more than 200 isolates of Streptomyces Actinobacteria. Chemical analyses of 15 of these isolates identified 11 distinct and structurally diverse secondary metabolites, including a novel polyunsaturated and polyoxygenated macrocyclic lactam, which we name sceliphrolactam. By pairing the 15 Streptomyces strains against a collection of fungi and bacteria, we document their antifungal and antibacterial activity. The prevalence and anti-microbial properties of Actinobacteria associated with these two solitary wasp species suggest the potential role of these Streptomyces as antibiotic-producing symbionts, potentially helping defend their wasp hosts from pathogenic microbes. Finding phylogenetically diverse and chemically prolific Actinobacteria from solitary wasps suggests that insect-associated Actinobacteria can provide a valuable source of novel natural products of pharmaceutical interest.

  12. Chemical and geotechnical analyses of soil samples from Olkiluoto for studies on sorption in soils

    International Nuclear Information System (INIS)

    Lusa, M.; Aemmaelae, K.; Hakanen, M.; Lehto, J.; Lahdenperae, A.-M.

    2009-05-01

    The safety assessment of disposal of spent nuclear fuel will include an estimate on the behavior of nuclear waste nuclides in the biosphere. As a part of this estimate also the transfer of nuclear waste nuclides in the soil and sediments is to be considered. In this study soil samples were collected from three excavator pits in Olkiluoto and the geotechnical and chemical characteristics of the samples were determined. In later stage these results will be used in sorption tests. Aim of these tests is to determine the Kd-values for Cs, Tc and I and later for Mo, Nb and Cl. Results of these sorption tests will be reported later. The geotechnical characteristics studied included dry weight and organic matter content as well as grain size distribution and mineralogy analyses. Selective extractions were carried out to study the sorption of cations into different mineral types. The extractions included five steps in which the cations bound to exchangeable, carbonate, oxides of Fe and Mn, organic matter and residual fractions were determined. For all fractions ICPMS analyses were carried out. In these analyses Li, Na, Mg, K, Ca, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Sr, Mo, Cd, Cs and Pb were determined. In addition six profiles were taken from the surroundings of two excavator pits for the 137 Cs determination. Besides the samples taken for the characterization of soil, supplement samples were taken from the same layers for the separation of soil water. From the soil water pH, DOC, anions (F, Cl, NO 3 , SO 4 ) and cations (Na, Mg, K, Ca, Al, Cr, Mn, Fe, Ni, Cu, Zn, As, S, Cd, Cs, Pb, U) were determined. (orig.)

  13. Analysing the New Taliban Code of Conduct (Layeha): An Assessment of Changing Perspectives and Strategies of the Afghan Taliban

    Science.gov (United States)

    2012-03-01

    Amir ul-Momineen)16 and his Deputy, who goes unnamed , unlike the 2009 version where Omar’s then most-trusted deputy, Mullah Abdul Ghani Berader, was...Chivers, C.J., 2011. In Eastern Afghanistan, at war with the Taliban’s shadowy rule. The New York Times, 6 Feb. Coll, S., 2004. Ghost wars: the secret...details, including instructions for authors and subscription information: http://www.tandfonline.com/loi/ccas20 Analysing the new Taliban Code of Conduct

  14. A systematic review of the quality of conduct and reporting of systematic reviews and meta-analyses in paediatric surgery.

    Directory of Open Access Journals (Sweden)

    Paul Stephen Cullis

    Full Text Available Our objective was to evaluate quality of conduct and reporting of published systematic reviews and meta-analyses in paediatric surgery. We also aimed to identify characteristics predictive of review quality.Systematic reviews summarise evidence by combining sources, but are potentially prone to bias. To counter this, the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA was published to aid in reporting. Similarly, the Assessing the Methodological Quality of Systematic Reviews (AMSTAR measurement tool was designed to appraise methodology. The paediatric surgical literature has seen an increasing number of reviews over the past decade, but quality has not been evaluated.Adhering to PRISMA guidelines, we performed a systematic review with a priori design to identify systematic reviews and meta-analyses of interventions in paediatric surgery. From 01/2010 to 06/2016, we searched: MEDLINE, EMBASE, Cochrane, Centre for Reviews and Dissemination, Web of Science, Google Scholar, reference lists and journals. Two reviewers independently selected studies and extracted data. We assessed conduct and reporting using AMSTAR and PRISMA. Scores were calculated as the sum of reported items. We also extracted author, journal and article characteristics, and used them in exploratory analysis to determine which variables predict quality.112 articles fulfilled eligibility criteria (53 systematic reviews; 59 meta-analyses. Overall, 68% AMSTAR and 56.8% PRISMA items were reported adequately. Poorest scores were identified with regards a priori design, inclusion of structured summaries, including the grey literature, citing excluded articles and evaluating bias. 13 reviews were pre-registered and 6 in PRISMA-endorsing journals. The following predicted quality in univariate analysis:, word count, Cochrane review, journal h-index, impact factor, journal endorses PRISMA, PRISMA adherence suggested in author guidance, article mentions PRISMA

  15. Conductivity enhancement via chemical modification of chitosan based green polymer electrolyte

    International Nuclear Information System (INIS)

    Mobarak, N.N.; Ahmad, A.; Abdullah, M.P.; Ramli, N.; Rahman, M.Y.A.

    2013-01-01

    The potential of carboxymethyl chitosan as a green polymer electrolyte has been explored. Chitosan produced from partial deacetylation of chitin was reacted with monochloroacetic acid to form carboxymethyl chitosan. A green polymer electrolyte based chitosan and carboxymethyl chitosan was prepared by solution-casting technique. The powder and films were characterized by reflection Fourier transform infrared (ATR-FTIR) spectroscopy, 1 H nuclear magnetic resonance, elemental analysis and X-ray diffraction, electrochemical impedance spectroscopy, and scanning electron microscopy. The shift of wavenumber that represents hydroxyl and amine stretching confirmed the polymer solvent complex formation. The XRD spectra results show that chemical modification of chitosan has improved amorphous properties of chitosan. The ionic conductivity was found to increase by two magnitudes higher with the chemical modification of chitosan. The highest conductivity achieved was 3.6 × 10 −6 S cm −1 for carboxymethyl chitosan at room temperature and 3.7 × 10 −4 S cm −1 at 60 °C

  16. Assessing the Extent of Sediment Contamination Around Creosote-treated Pilings Through Chemical and Biological Analyses

    Science.gov (United States)

    Stefansson, E. S.

    2008-12-01

    Creosote is a common wood preservative used to treat marine structures, such as docks and bulkheads. Treated dock pilings continually leach polycyclic aromatic hydrocarbons (PAHs) and other creosote compounds into the surrounding water and sediment. Over time, these compounds can accumulate in marine sediments, reaching much greater concentrations than those in seawater. The purpose of this study was to assess the extent of creosote contamination in sediments, at a series of distances from treated pilings. Three pilings were randomly selected from a railroad trestle in Fidalgo Bay, WA and sediment samples were collected at four distances from each: 0 meters, 0.5 meters, 1 meter, and 2 meters. Samples were used to conduct two bioassays: an amphipod bioassay (Rhepoxynius abronius) and a sand dollar embryo bioassay. Grain size and PAH content (using a fluorometric method) were also measured. Five samples in the amphipod bioassay showed significantly lower effective survival than the reference sediment. These consisted of samples closest to the piling at 0 and 0.5 meters. One 0 m sample in the sand dollar embryo bioassay also showed a significantly lower percentage of normal embryos than the reference sediment. Overall, results strongly suggest that creosote-contaminated sediments, particularly those closest to treated pilings, can negatively affect both amphipods and echinoderm embryos. Although chemical data were somewhat ambiguous, 0 m samples had the highest levels of PAHs, which corresponded to the lowest average survival in both bioassays. Relatively high levels of PAHs were found as far as 2 meters away from pilings. Therefore, we cannot say how far chemical contamination can spread from creosote-treated pilings, and at what distance this contamination can still affect marine organisms. These results, as well as future research, are essential to the success of proposed piling removal projects. In addition to creosote-treated pilings, contaminated sediments must

  17. Physico-chemical analyses of Hispano-Moresque lustred ceramic: a precursor for Italian majolica?

    Science.gov (United States)

    Chabanne, D.; Bouquillon, A.; Aucouturier, M.; Dectot, X.; Padeletti, G.

    2008-07-01

    The paper presents a comprehensive physico-chemical investigation on a series of Hispano-Moresque objects produced in the eastern Spain workshops between the XIV and XVIII centuries and fragments from XII century, in order to compare them with the Italian Renaissance majolica production. The techniques used are mainly non-destructive (ion beam analyses and X-ray diffraction), sometimes complemented by SEM observation and microanalysis, and electrothermal atomic emission spectrometry. Such methods allow a full description of the terra cotta, of the glaze and of the different surface layers which constitute the lustre decoration indicating individual elemental composition and thickness of each layer containing or not metallic nanoparticles. Principal results show the following: i) a constant source of supply for the eastern Spain terra cotta; ii) a significant change in the composition of the Spanish glazes around the XVII century, with the disappearance of the opacifying tin oxide addition; iii) significant evolutions in the structure and composition of the lustre layers, in particular related to the presence or not of a metal-free surface glaze film and its thickness; iv) interesting analogies and differences with the Italian majolica; v) confirmation of the change in the quality of blue pigment during XVI century, already evidenced by the authors in previous publications. A discussion about the transmission of the lustre technique between eastern Spain and Italy at the Renaissance period is proposed.

  18. Electrical Conductivity and Chemical Composition of Soil Solution: Comparison of Solution Samplers in Tropical Soils

    Directory of Open Access Journals (Sweden)

    Davi Lopes do Carmo

    2016-01-01

    Full Text Available ABSTRACT Soil solution samplers may have the same working principle, but they differ in relation to chemical and physical characteristics, cost and handling, and these aspects exert influence on the chemical composition of the soil solution obtained. This study was carried out to evaluate, over time, the chemical composition of solutions extracted by Suolo Acqua, with the hydrophilic membrane (HM as a standard, using soils with contrasting characteristics, and to determine the relationship between electrical conductivity (EC and concentration of ions and pH of soil solution samples. This study was carried out under laboratory conditions, using three soils samples with different clay and organic matter (OM contents. Soil solution contents of F−, Cl−, NO−3, Br−, SO42−, Na+, NH4+, K+, Mg2+, Ca2+, were analyzed, as well as inorganic, organic, and total C contents, pH, and EC, in four successive sampling times. Soil solution chemical composition extracted by the Suolo Acqua sampler is similar to that collected by the HM, but the Suolo Acqua extracted more Na+ and soluble organic C than the HM solution. Solution EC, cation and anion concentrations, and soluble C levels are higher in the soil with greater clay and OM contents (Latossolo and Cambissolo in this case. Soil solution composition varied over time, with considerable changes in pH, EC, and nutrient concentrations, especially associated with soil OM. Thus, single and isolated sampling of the soil solution must be avoided, otherwise composition of the soil solution may not be correctly evaluated. Soil solution EC was regulated by pH, as well as the sum of cation and anion concentrations, and the C contents determined in the soil liquid phase.

  19. Preparation of high surface area and high conductivity polyaniline nanoparticles using chemical oxidation polymerization technique

    Science.gov (United States)

    Budi, S.; Yusmaniar; Juliana, A.; Cahyana, U.; Purwanto, A.; Imaduddin, A.; Handoko, E.

    2018-03-01

    In this work, polyaniline nanoparticles were synthesized using a chemical oxidation polymerization technique. The ammonium peroxydisulfate (APS)/aniline ratio, APS dropping time, and polymerization temperature were optimized to increase the surface area and conductivity of the polyaniline.The Fourier-transform infrared (FTIR) spectrum confirmed the formation of emeraldine salt polyaniline. X-ray diffraction (XRD) patterns indicated that amorphous and crystalline phases of the polyaniline were formed with crystallinity less than 40%. Scanning electron microscope (SEM) micrographs showed that the finest nanoparticles with uniform size distribution were obtained at the polymerization temperature of 0°C. A surface area analyzer (SAA) showed that the highest Brunauer-Emmett-Teller surface area (SBET ) of 42.14 m2/gwas obtained from an APS/aniline ratio of 0.75 with a dropping time of 0 s at a polymerization temperature of 0°C. A four-point probe measurement conducted at 75–300K indicated relatively high conductivity of the semiconductor characteristic of the polyaniline.

  20. Oxidation state analyses of uranium with emphasis on chemical speciation in geological media

    International Nuclear Information System (INIS)

    Ervanne, H.

    2004-01-01

    , linearity, repeatability and comparability of methods were examined. Both Nd-coprecipitation and ion exchange were found to be valid and reliable methods. Both are suitable tools for studying oxidation/reduction mechanisms in geochemical processes. The oxidation state analyses of uranium in different geological materials gave new information on the chemical speciation and behaviour of uranium. (orig.)

  1. On Conducting Construct Validity Meta-Analyses for the Rorschach: A Reply to Tibon Czopp and Zeligman (2016).

    Science.gov (United States)

    Mihura, Joni L; Meyer, Gregory J; Dumitrascu, Nicolae; Bombel, George

    2016-01-01

    We respond to Tibon Czopp and Zeligman's (2016) critique of our systematic reviews and meta-analyses of 65 Rorschach Comprehensive System (CS) variables published in Psychological Bulletin (2013). The authors endorsed our supportive findings but critiqued the same methodology when used for the 13 unsupported variables. Unfortunately, their commentary was based on significant misunderstandings of our meta-analytic method and results, such as thinking we used introspectively assessed criteria in classifying levels of support and reporting only a subset of our externally assessed criteria. We systematically address their arguments that our construct label and criterion variable choices were inaccurate and, therefore, meta-analytic validity for these 13 CS variables was artificially low. For example, the authors created new construct labels for these variables that they called "the customary CS interpretation," but did not describe their methodology nor provide evidence that their labels would result in better validity than ours. They cite studies they believe we should have included; we explain how these studies did not fit our inclusion criteria and that including them would have actually reduced the relevant CS variables' meta-analytic validity. Ultimately, criticisms alone cannot change meta-analytic support from negative to positive; Tibon Czopp and Zeligman would need to conduct their own construct validity meta-analyses.

  2. Thermal conductivity of ultra-thin chemical vapor deposited hexagonal boron nitride films

    International Nuclear Information System (INIS)

    Alam, M. T.; Haque, M. A.; Bresnehan, M. S.; Robinson, J. A.

    2014-01-01

    Thermal conductivity of freestanding 10 nm and 20 nm thick chemical vapor deposited hexagonal boron nitride films was measured using both steady state and transient techniques. The measured value for both thicknesses, about 100 ± 10 W m −1 K −1 , is lower than the bulk basal plane value (390 W m −1 K −1 ) due to the imperfections in the specimen microstructure. Impressively, this value is still 100 times higher than conventional dielectrics. Considering scalability and ease of integration, hexagonal boron nitride grown over large area is an excellent candidate for thermal management in two dimensional materials-based nanoelectronics

  3. Eddy Heat Conduction and Nonlinear Stability of a Darcy Lapwood System Analysed by the Finite Spectral Method

    Directory of Open Access Journals (Sweden)

    Jónas Elíasson

    2014-01-01

    Full Text Available A finite Fourier transform is used to perform both linear and nonlinear stability analyses of a Darcy-Lapwood system of convective rolls. The method shows how many modes are unstable, the wave number instability band within each mode, the maximum growth rate (most critical wave numbers on each mode, and the nonlinear growth rates for each amplitude as a function of the porous Rayleigh number. Single amplitude controls the nonlinear growth rates and thereby the physical flow rate and fluid velocity, on each mode. They are called the flak amplitudes. A discrete Fourier transform is used for numerical simulations and here frequency combinations appear that the traditional cut-off infinite transforms do not have. The discrete show a stationary solution in the weak instability phase, but when carried past 2 unstable modes they show fluctuating motion where all amplitudes except the flak may be zero on the average. This leads to a flak amplitude scaling process of the heat conduction, producing an eddy heat conduction coefficient where a Nu-RaL relationship is found. It fits better to experiments than previously found solutions but is lower than experiments.

  4. Transparent conducting oxide films of group V doped titania prepared by aqueous chemical solution deposition

    International Nuclear Information System (INIS)

    Elen, Ken; Capon, Boris; De Dobbelaere, Christopher; Dewulf, Daan; Peys, Nick; Detavernier, Christophe; Hardy, An; Van Bael, Marlies K.

    2014-01-01

    Transparent conducting oxide (TCO) films of titania doped with vanadium (V), niobium (Nb) and tantalum (Ta) are obtained by aqueous Chemical Solution Deposition (CSD). The effect of the dopant on the crystallization and microstructure of the resulting films is examined by means of X-ray diffraction and electron microscopy. During annealing of the thin films, in-situ characterization of the crystal structure and sheet resistance is carried out. Niobium doped anatase films, obtained after annealing in forming gas, show a resistivity of 0,28 Ohm cm, which is the lowest resistivity reported for a solution deposited anatase-based TCO so far. Here, we demonstrate that aqueous CSD may provide a strategy for scalable TCO production in the future. - Highlights: • Aqueous chemical solution deposition of doped titanium dioxide • Doping delays the phase transition from anatase to rutile • Lowest resistivity after doping with niobium and annealing in Forming Gas • Transparency higher than 80% in the visible range of optical spectrum

  5. Transparent conducting oxide films of group V doped titania prepared by aqueous chemical solution deposition

    Energy Technology Data Exchange (ETDEWEB)

    Elen, Ken [Inorganic and Physical Chemistry, Institute for Materials Research, Hasselt University, Agoralaan Building D, B-3590 Diepenbeek (Belgium); IMEC vzw division IMOMEC, Agoralaan Building D, B-3590 Diepenbeek (Belgium); Strategisch Initiatief Materialen (SIM), SoPPoM Program (Belgium); Capon, Boris [Strategisch Initiatief Materialen (SIM), SoPPoM Programm (Belgium); Coating and Contacting of Nanostructures, Ghent University, Krijgslaan 281 S1, B-9000 Ghent (Belgium); De Dobbelaere, Christopher [Inorganic and Physical Chemistry, Institute for Materials Research, Hasselt University, Agoralaan Building D, B-3590 Diepenbeek (Belgium); Dewulf, Daan [Inorganic and Physical Chemistry, Institute for Materials Research, Hasselt University, Agoralaan Building D, B-3590 Diepenbeek (Belgium); IMEC vzw division IMOMEC, Agoralaan Building D, B-3590 Diepenbeek (Belgium); Peys, Nick [Inorganic and Physical Chemistry, Institute for Materials Research, Hasselt University, Agoralaan Building D, B-3590 Diepenbeek (Belgium); IMEC vzw, Kapeldreef 75, B-3001 Heverlee (Belgium); Detavernier, Christophe [Coating and Contacting of Nanostructures, Ghent University, Krijgslaan 281 S1, B-9000 Ghent (Belgium); Hardy, An [Inorganic and Physical Chemistry, Institute for Materials Research, Hasselt University, Agoralaan Building D, B-3590 Diepenbeek (Belgium); IMEC vzw division IMOMEC, Agoralaan Building D, B-3590 Diepenbeek (Belgium); Van Bael, Marlies K., E-mail: marlies.vanbael@uhasselt.be [Inorganic and Physical Chemistry, Institute for Materials Research, Hasselt University, Agoralaan Building D, B-3590 Diepenbeek (Belgium); IMEC vzw division IMOMEC, Agoralaan Building D, B-3590 Diepenbeek (Belgium)

    2014-03-31

    Transparent conducting oxide (TCO) films of titania doped with vanadium (V), niobium (Nb) and tantalum (Ta) are obtained by aqueous Chemical Solution Deposition (CSD). The effect of the dopant on the crystallization and microstructure of the resulting films is examined by means of X-ray diffraction and electron microscopy. During annealing of the thin films, in-situ characterization of the crystal structure and sheet resistance is carried out. Niobium doped anatase films, obtained after annealing in forming gas, show a resistivity of 0,28 Ohm cm, which is the lowest resistivity reported for a solution deposited anatase-based TCO so far. Here, we demonstrate that aqueous CSD may provide a strategy for scalable TCO production in the future. - Highlights: • Aqueous chemical solution deposition of doped titanium dioxide • Doping delays the phase transition from anatase to rutile • Lowest resistivity after doping with niobium and annealing in Forming Gas • Transparency higher than 80% in the visible range of optical spectrum.

  6. Harmonisation of food consumption data format for dietary exposure assessments of chemicals analysed in raw agricultural commodities

    DEFF Research Database (Denmark)

    Boon, Polly E.; Ruprich, Jiri; Petersen, Annette

    2009-01-01

    In this paper, we present an approach to format national food consumption data at raw agricultural commodity (RAC) level. In this way, the data is both formatted in a harmonised way given the comparability of RACs between countries, and suitable to assess the dietary exposure to chemicals analysed......, and the use of the FAO/WHO Codex Classification system of Foods and Animal Feeds to harmonise the classification. We demonstrate that this approach works well for pesticides and glycoalkaloids, and is an essential step forward in the harmonisation of risk assessment procedures within Europe when addressing...... chemicals analysed in RACs by all national food control systems....

  7. Metal and physico-chemical variations at a hydroelectric reservoir analyzed by Multivariate Analyses and Artificial Neural Networks: environmental management and policy/decision-making tools.

    Science.gov (United States)

    Cavalcante, Y L; Hauser-Davis, R A; Saraiva, A C F; Brandão, I L S; Oliveira, T F; Silveira, A M

    2013-01-01

    This paper compared and evaluated seasonal variations in physico-chemical parameters and metals at a hydroelectric power station reservoir by applying Multivariate Analyses and Artificial Neural Networks (ANN) statistical techniques. A Factor Analysis was used to reduce the number of variables: the first factor was composed of elements Ca, K, Mg and Na, and the second by Chemical Oxygen Demand. The ANN showed 100% correct classifications in training and validation samples. Physico-chemical analyses showed that water pH values were not statistically different between the dry and rainy seasons, while temperature, conductivity, alkalinity, ammonia and DO were higher in the dry period. TSS, hardness and COD, on the other hand, were higher during the rainy season. The statistical analyses showed that Ca, K, Mg and Na are directly connected to the Chemical Oxygen Demand, which indicates a possibility of their input into the reservoir system by domestic sewage and agricultural run-offs. These statistical applications, thus, are also relevant in cases of environmental management and policy decision-making processes, to identify which factors should be further studied and/or modified to recover degraded or contaminated water bodies. Copyright © 2012 Elsevier B.V. All rights reserved.

  8. Composition and conductance distributions of single GeSi quantum rings studied by conductive atomic force microscopy combined with selective chemical etching.

    Science.gov (United States)

    Lv, Y; Cui, J; Jiang, Z M; Yang, X J

    2013-02-15

    Atomic force microscopy imaging combined with selective chemical etching is employed to quantitatively investigate three-dimensional (3D) composition distributions of single GeSi quantum rings (QRs). In addition, the 3D quantitative composition distributions and the corresponding conductance distributions are simultaneously obtained on the same single GeSi QRs by conductive atomic force microscopy combined with selective chemical etching, allowing us to investigate the correlations between the conductance and composition distributions of single QRs. The results show that the QRs' central holes have higher Ge content, but exhibit lower conductance, indicating that the QRs' conductance distribution is not consistent with their composition distribution. By comparing the topography, composition and conductance profiles of the same single QRs before and after different etching processes, it is found that the conductance distributions of GeSi QRs do not vary with the change of composition distribution. Instead, the QRs' conductance distributions are found to be consistent with their topographic shapes, which can be supposed to be due to the shape determined electronic structures.

  9. Reprocessing of spent nuclear fuel, Annex 3: Chemical and radiometric control analyses

    International Nuclear Information System (INIS)

    Gal, I.

    1964-01-01

    Simple, fast and reliable control analyses are obligatory during reprocessing. The analyses performed covered measuring the contents of uranium in water and organic solutions, contents of plutonium in water and organic solutions as well as the free acid in both solutions. In addition temporary analyses were done to determine the density of water and organic solutions as well as content of TBP in kerosine

  10. Spectroscopic analyses of chemical adaptation processes within microalgal biomass in response to changing environments

    Energy Technology Data Exchange (ETDEWEB)

    Vogt, Frank, E-mail: fvogt@utk.edu; White, Lauren

    2015-03-31

    Highlights: • Microalgae transform large quantities of inorganics into biomass. • Microalgae interact with their growing environment and adapt their chemical composition. • Sequestration capabilities are dependent on cells’ chemical environments. • We develop a chemometric hard-modeling to describe these chemical adaptation dynamics. • This methodology will enable studies of microalgal compound sequestration. - Abstract: Via photosynthesis, marine phytoplankton transforms large quantities of inorganic compounds into biomass. This has considerable environmental impacts as microalgae contribute for instance to counter-balancing anthropogenic releases of the greenhouse gas CO{sub 2}. On the other hand, high concentrations of nitrogen compounds in an ecosystem can lead to harmful algae blooms. In previous investigations it was found that the chemical composition of microalgal biomass is strongly dependent on the nutrient availability. Therefore, it is expected that algae’s sequestration capabilities and productivity are also determined by the cells’ chemical environments. For investigating this hypothesis, novel analytical methodologies are required which are capable of monitoring live cells exposed to chemically shifting environments followed by chemometric modeling of their chemical adaptation dynamics. FTIR-ATR experiments have been developed for acquiring spectroscopic time series of live Dunaliella parva cultures adapting to different nutrient situations. Comparing experimental data from acclimated cultures to those exposed to a chemically shifted nutrient situation reveals insights in which analyte groups participate in modifications of microalgal biomass and on what time scales. For a chemometric description of these processes, a data model has been deduced which explains the chemical adaptation dynamics explicitly rather than empirically. First results show that this approach is feasible and derives information about the chemical biomass

  11. Spectroscopic analyses of chemical adaptation processes within microalgal biomass in response to changing environments

    International Nuclear Information System (INIS)

    Vogt, Frank; White, Lauren

    2015-01-01

    Highlights: • Microalgae transform large quantities of inorganics into biomass. • Microalgae interact with their growing environment and adapt their chemical composition. • Sequestration capabilities are dependent on cells’ chemical environments. • We develop a chemometric hard-modeling to describe these chemical adaptation dynamics. • This methodology will enable studies of microalgal compound sequestration. - Abstract: Via photosynthesis, marine phytoplankton transforms large quantities of inorganic compounds into biomass. This has considerable environmental impacts as microalgae contribute for instance to counter-balancing anthropogenic releases of the greenhouse gas CO 2 . On the other hand, high concentrations of nitrogen compounds in an ecosystem can lead to harmful algae blooms. In previous investigations it was found that the chemical composition of microalgal biomass is strongly dependent on the nutrient availability. Therefore, it is expected that algae’s sequestration capabilities and productivity are also determined by the cells’ chemical environments. For investigating this hypothesis, novel analytical methodologies are required which are capable of monitoring live cells exposed to chemically shifting environments followed by chemometric modeling of their chemical adaptation dynamics. FTIR-ATR experiments have been developed for acquiring spectroscopic time series of live Dunaliella parva cultures adapting to different nutrient situations. Comparing experimental data from acclimated cultures to those exposed to a chemically shifted nutrient situation reveals insights in which analyte groups participate in modifications of microalgal biomass and on what time scales. For a chemometric description of these processes, a data model has been deduced which explains the chemical adaptation dynamics explicitly rather than empirically. First results show that this approach is feasible and derives information about the chemical biomass adaptations

  12. Researching chemicals in human milk can be conducted without discouraging breastfeeding

    Directory of Open Access Journals (Sweden)

    José G. Dórea

    2012-05-01

    Health Organization recommends six months of exclusive breastfeeding. Cinar et al. [1] recognized that human milk provides all of the vitamins and essential minerals and trace elements (micronutrients that are required for the normal development of infants as well as many brain-protective substances. They do not describe the exposures associated with formula-feeding in the regions under study and so the reader has no basis for understanding whether infant exposures to metals would be higher or lower based on the choice of formula over breastfeeding. Further, there is no evidence that formula feeding would attenuate any effects that may occur from fetal exposures [3]. Scientists conducting biomonitoring research using human milk have an obligation to understand the sensitivity of this issue and the impact their information and/or message may have on health professionals and breastfeeding mothers. Indeed, Geraghty et al. [4] highlighted the potential harm from poor reporting methods in breast milk monitoring of environmental chemicals; American women responded that they would immediately wean if told that phthalates were in their milk. It is incumbent on us to strive to contextualize human milk biomonitoring data, constructing a message that puts into perspective both risks of environmental hazards and benefits of breastfeeding. Formula-feeding should never be implied (implicitly or explicitly as a means to attenuate maternal-infant exposure to environmental chemicals, especially without data to support such a message (5. The otherwise interesting paper of Cinar et al. [1] gives the false impression that milk of Turkish mothers is unsafe and that if the infant is not breastfed, chemical exposures will not occur.

  13. Structural, chemical and electrical characterisation of conductive graphene-polymer composite films

    Energy Technology Data Exchange (ETDEWEB)

    Brennan, Barry; Spencer, Steve J.; Belsey, Natalie A. [National Physical Laboratory, Teddington, TW11 0LW (United Kingdom); Faris, Tsegie [DZP Technologies Ltd., Future Business Centre, Cambridge, CB4 2HY (United Kingdom); Cronin, Harry [DZP Technologies Ltd., Future Business Centre, Cambridge, CB4 2HY (United Kingdom); Advanced Technology Institute (ATI), University of Surrey, Guildford, GU2 7XH (United Kingdom); Silva, S. Ravi P. [Advanced Technology Institute (ATI), University of Surrey, Guildford, GU2 7XH (United Kingdom); Sainsbury, Toby; Gilmore, Ian S. [National Physical Laboratory, Teddington, TW11 0LW (United Kingdom); Stoeva, Zlatka [DZP Technologies Ltd., Future Business Centre, Cambridge, CB4 2HY (United Kingdom); Pollard, Andrew J., E-mail: andrew.pollard@npl.co.uk [National Physical Laboratory, Teddington, TW11 0LW (United Kingdom)

    2017-05-01

    Graphical abstract: Secondary Ion Mass Spectrometry (SIMS) imaging of the dispersion of graphene within graphene-polymer composites using the Na{sup +} signal. - Highlights: • Relation of properties of graphene flakes with electrical properties of composite. • Standardised characterisation method for structural properties of graphene flakes. • Structural and chemical characterisation of commercial graphene flakes. • ToF-SIMS used to determine dispersion of graphene in polymer. - Abstract: Graphene poly-acrylic and PEDOT:PSS nanocomposite films were produced using two alternative commercial graphene powders to explore how the graphene flake dimensions and chemical composition affected the electrical performance of the film. A range of analytical techniques, including scanning electron microscopy (SEM), atomic force microscopy (AFM), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS), were employed to systematically analyse the initial graphene materials as well as the nanocomposite films. Electrical measurements indicated that the sheet resistance of the films was affected by the properties of the graphene flakes used. To further explore the composition of the films, ToF-SIMS mapping was employed and provided a direct means to elucidate the nature of the graphene dispersion in the films and to correlate this with the electrical analysis. These results reveal important implications for how the dispersion of the graphene material in films produced from printable inks can be affected by the type of graphene powder used and the corresponding effect on electrical performance of the nanocomposites. This work provides direct evidence for how accurate and comparable characterisation of the graphene material is required for real-world graphene materials to develop graphene enabled films and proposes a measurement protocol for comparing graphene materials that can be used for international

  14. Laminated chemical and physical micro-jet actuators based on conductive media

    Science.gov (United States)

    Gadiraju, Priya D.

    2008-04-01

    This dissertation presents the development of electrically-powered, lamination-based microactuators for the realization of large arrays of high impulse and short duration micro-jets with potential applications in the field of micro-electro-mechanical systems (MEMS). Microactuators offer unique control opportunities by converting the input electrical or chemical energy stored in a propellant into useful mechanical energy. This small and precise control obtained can potentially be applied towards aerodynamic control and transdermal drug delivery applications. This thesis work discusses the feasibility of using microactuators for two such applications: Control of the motion of a spinning projectile by utilizing the chemically-driven microjets ejected from the actuators, and enhancement of the permeability properties of skin by selectively ablating the stratum corneum layer of skin using the physical microjets ejected from the actuators. This enhanced permeability of skin can later be used for the delivery of high molecular weight drugs for transdermal drug delivery. The development of electrically powered microactuators starts by fabricating an array of radially firing microactuators using lamination-based microfabrication techniques that potentially enable batch fabrication at low cost. The microactuators of this thesis consist of three main parts: a micro chamber in which the propellant is stored; two electrode structures through which electrical energy is supplied to the propellant; and a micro nozzle through which the propellant or released gases from the propellant are expanded as a jet. Once the actuators are fabricated, they are integrated with MEMS-process-compatible propellants and optimized so as to produce instantaneous ignition of the propellant. This instantaneous ignition is achieved either by making the propellant itself conductive, thus, passing an electric current directly through the propellant; or by discharging an arc across the propellant by

  15. Evaluation of Two Surface Sampling Methods for Microbiological and Chemical Analyses To Assess the Presence of Biofilms in Food Companies.

    Science.gov (United States)

    Maes, Sharon; Huu, Son Nguyen; Heyndrickx, Marc; Weyenberg, Stephanie van; Steenackers, Hans; Verplaetse, Alex; Vackier, Thijs; Sampers, Imca; Raes, Katleen; Reu, Koen De

    2017-12-01

    Biofilms are an important source of contamination in food companies, yet the composition of biofilms in practice is still mostly unknown. The chemical and microbiological characterization of surface samples taken after cleaning and disinfection is very important to distinguish free-living bacteria from the attached bacteria in biofilms. In this study, sampling methods that are potentially useful for both chemical and microbiological analyses of surface samples were evaluated. In the manufacturing facilities of eight Belgian food companies, surfaces were sampled after cleaning and disinfection using two sampling methods: the scraper-flocked swab method and the sponge stick method. Microbiological and chemical analyses were performed on these samples to evaluate the suitability of the sampling methods for the quantification of extracellular polymeric substance components and microorganisms originating from biofilms in these facilities. The scraper-flocked swab method was most suitable for chemical analyses of the samples because the material in these swabs did not interfere with determination of the chemical components. For microbiological enumerations, the sponge stick method was slightly but not significantly more effective than the scraper-flocked swab method. In all but one of the facilities, at least 20% of the sampled surfaces had more than 10 2 CFU/100 cm 2 . Proteins were found in 20% of the chemically analyzed surface samples, and carbohydrates and uronic acids were found in 15 and 8% of the samples, respectively. When chemical and microbiological results were combined, 17% of the sampled surfaces were contaminated with both microorganisms and at least one of the analyzed chemical components; thus, these surfaces were characterized as carrying biofilm. Overall, microbiological contamination in the food industry is highly variable by food sector and even within a facility at various sampling points and sampling times.

  16. Elaboration process, chemical and sensory analyses of fried-salted soybean

    Directory of Open Access Journals (Sweden)

    Gayol, María F.

    2010-09-01

    Full Text Available The purpose of this work was to develop an elaboration process of fried-salted soybean and to determine the chemical composition, consumer acceptance and sensory description of the product. Different fried-salted soybean products were obtained under different temperature and time conditions by maceration in water, roasting and frying. Four of the best products were selected and evaluated by consumers (overall, color and texture acceptances: FSS1, FSS2, FSS3 and FSS4. The product with the highest consumer acceptance (7 = “like moderately” in a hedonic scale of 9 points was the one obtained by maceration at 100°C during 10 min and fried at 170°C for 5 min (FSS3. Proximate and fatty acid composition along with sensory attribute intensity ratings from descriptive analyses were determined on the fried-salted soybean with the highest consumer acceptance (FSS3. Proximate and fatty acid composition were also determined in raw soybeans. FSS3 had lower percentages of moisture and proteins, and higher lipids and carbohydrates than raw soybean. The use of sunflower oil in the frying process improved the fatty acid composition of the soybean product. Sensory attributes from descriptive analyses that were detected in high intensity ratings for the product were roasted, salty, crunchiness, hardness, brown color and gloss. This product is neither commonly consumed nor easily available in markets. It could be promoted to be consumed as a snack because of its high nutritional and sensory quality.

    El propósito de este trabajo fue desarrollar un proceso de elaboración de soja frita salada, determinar la composición química, la aceptabilidad por consumidores y la descripción sensorial del producto. Diferentes productos de soja frita salada fueron obtenidos bajo diferentes condiciones de temperatura y tiempo de: maceración, tostado y fritura. Los consumidores evaluaron y seleccionaron los cuatro mejores productos, los que presentaron mayor aceptaci

  17. Correlation and regression analyses of genetic effects for different types of cells in mammals under radiation and chemical treatment

    International Nuclear Information System (INIS)

    Slutskaya, N.G.; Mosseh, I.B.

    2006-01-01

    Data about genetic mutations under radiation and chemical treatment for different types of cells have been analyzed with correlation and regression analyses. Linear correlation between different genetic effects in sex cells and somatic cells have found. The results may be extrapolated on sex cells of human and mammals. (authors)

  18. A chemically stable electrolyte with a novel sandwiched structure for proton-conducting solid oxide fuel cells (SOFCs)

    KAUST Repository

    Bi, Lei; Traversa, Enrico

    2013-01-01

    A chemically stable electrolyte structure was developed for proton-conducting SOFCs by using two layers of stable BaZr0.7Pr 0.1Y0.2O3 -δ to sandwich a highly-conductive but unstable BaCe0.8Y0.2O 3 -δ electrolyte layer. The sandwiched electrolyte

  19. Dental caries and chemical analyses in reconstruction of diet, health and hygienic behaviour in the Middle Euphrates valley (Syria).

    Science.gov (United States)

    Tomczyk, Jacek; Szostek, Krzysztof; Komarnitki, Iulian; Mańkowska-Pliszka, Hanna; Zalewska, Marta

    2013-06-01

    The aim of this study was to use two methods, biological and chemical, to examine changes in diet and health in individuals from the Middle Euphrates valley (Syria). We determined the frequency distribution of dental caries. Chemical analyses were concerned with the presence of elements such as strontium, barium, calcium and stable carbon isotopes ((13)C/(14)C). We chose three consecutive periods: Late Roman (2nd-4th century AD), Islamic (600-1200 AD) and Modern Islamic (1850-1950 AD). We analysed the dental remains of 145 individuals, with a total of 2530 teeth. We used visual research (magnifying glass/sharp dental probe) and radiography. The frequencies of caries were calculated on the basis of the proportional correction factor of Erdal and Duyar. We chose 39 permanent second molars for chemical analyses. The frequency of carious lesions was similar in all three periods (6-8%). In the Modern Islamic and Islamic periods, occlusal surfaces were infected with caries most often, while the cemento-enamel junction (CEJ) and approximal surfaces were affected to a lesser degree. However, in the Late Roman period, the CEJ and approximal surfaces showed caries most frequently, in contrast to occlusal surfaces, which seldom showed signs of caries. Chemical analyses showed lower Sr/Ca ratios and Observed Ratio index values for the Modern Islamic and higher values for the Islamic and Late Roman periods. Mean stable isotope (δ(13)C) analyses demonstrated that the Modern Islamic period was strongly divergent from the other periods. These data suggest a similar socio-economic status during the Late Roman and Islamic periods. The diet of the population living in the Late Roman and Islamic periods contained a larger number of products containing strontium than calcium. In the modern population these proportions have been reversed. Copyright © 2013 Elsevier Ltd. All rights reserved.

  20. Numerical tables on physical and chemical analyses of Rhine water 1983

    International Nuclear Information System (INIS)

    1984-01-01

    The numerical tables contain the measuring results of the physical-chemical studies on the Rhine water for the year 1983. The tables are arranged by general parameters, organic matter, eutrophicating substances, anorganic matter, metals, organic micropollution as well as by radioactivity (total alpha- or beta- and T-activity). (MM) [de

  1. Transparent conductive zinc-oxide-based films grown at low temperature by mist chemical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    Shirahata, Takahiro [New Energy and Environmental Business Division, Toshiba Mitsubishi-Electric Industrial Systems Corporation, Kobe International Business Center (KIBC) 509, 5-5-2 Minatojima-Minami, Chuo-Ku, Kobe 650-0047 (Japan); Kawaharamura, Toshiyuki [Research Institute, Kochi University of Technology, Kami, Kochi 780-8502 (Japan); School of Systems Engineering, Kochi University of Technology, Kami, Kochi 780-8502 (Japan); Fujita, Shizuo, E-mail: fujitasz@kuee.kyoto-u.ac.jp [Photonics and Electronics Science and Engineering Center, Kyoto University, Katsura, Nishikyo-ku, Kyoto 615-8520 (Japan); Orita, Hiroyuki [New Energy and Environmental Business Division, Toshiba Mitsubishi-Electric Industrial Systems Corporation, Kobe International Business Center (KIBC) 509, 5-5-2 Minatojima-Minami, Chuo-Ku, Kobe 650-0047 (Japan)

    2015-12-31

    Atmospheric pressure mist chemical vapor deposition (Mist–CVD) systems have been developed to grow zinc-oxide-based (ZnO-based) transparent conductive oxide (TCO) films. Low-resistive aluminum-doped ZnO (AZO) TCOs, showing resistivity of the order on 10{sup −4} Ωcm, previously were grown using a safe source material zinc acetate [Zn(ac){sub 2}], at a growth temperature as high as 500 °C. To grow superior TCOs at lower temperatures, we proposed the addition of NH{sub 3} to accelerate the reaction of acetylacetonate compounds. As the result, we could grow gallium-doped ZnO (GZO) TCOs with a resistivity of 2.7 × 10{sup −3} Ω cm and transmittance higher than 90% at 300 °C by using zinc acetylacetonate [Zn(acac){sub 2}] as the Zn source. To grow boron-doped ZnO (BZO) TCOs at a lower growth temperature of 200 °C, we used boron doping along with a toluene solution of diethylzinc (DEZ), that maintained high reactivity without being flammable. These BZO TCOs showed a resistivity of 1.5 × 10{sup −3} Ω cm and transmittance higher than 90%, despite the use of a non-vacuum-based open-air technology. - Highlights: • Introduction of Mist–CVD as a non-vacuum-based, safe, and cost-effective growth technology • Process evolution of the growth technology to lower the growth temperature. • Achievement of low resistive ZnO films at 200oC.

  2. Transparent conductive zinc-oxide-based films grown at low temperature by mist chemical vapor deposition

    International Nuclear Information System (INIS)

    Shirahata, Takahiro; Kawaharamura, Toshiyuki; Fujita, Shizuo; Orita, Hiroyuki

    2015-01-01

    Atmospheric pressure mist chemical vapor deposition (Mist–CVD) systems have been developed to grow zinc-oxide-based (ZnO-based) transparent conductive oxide (TCO) films. Low-resistive aluminum-doped ZnO (AZO) TCOs, showing resistivity of the order on 10"−"4 Ωcm, previously were grown using a safe source material zinc acetate [Zn(ac)_2], at a growth temperature as high as 500 °C. To grow superior TCOs at lower temperatures, we proposed the addition of NH_3 to accelerate the reaction of acetylacetonate compounds. As the result, we could grow gallium-doped ZnO (GZO) TCOs with a resistivity of 2.7 × 10"−"3 Ω cm and transmittance higher than 90% at 300 °C by using zinc acetylacetonate [Zn(acac)_2] as the Zn source. To grow boron-doped ZnO (BZO) TCOs at a lower growth temperature of 200 °C, we used boron doping along with a toluene solution of diethylzinc (DEZ), that maintained high reactivity without being flammable. These BZO TCOs showed a resistivity of 1.5 × 10"−"3 Ω cm and transmittance higher than 90%, despite the use of a non-vacuum-based open-air technology. - Highlights: • Introduction of Mist–CVD as a non-vacuum-based, safe, and cost-effective growth technology • Process evolution of the growth technology to lower the growth temperature. • Achievement of low resistive ZnO films at 200oC.

  3. Electrical conductivity and chemical stability of BaCe0· 8− xAxGd0 ...

    Indian Academy of Sciences (India)

    ... K. BaCe0.7In0.1Gd0.2O3− and BaCe0.7Zr0.1Gd0.2O3− ceramics exhibit an excellent chemical stability against boiling water. Indium is a suitable doping element to promote the sintering densification and to enhance both electrical conductivity and chemical stability of Gd-doped BaCeO3 at operating temperatures.

  4. Extra virgin olive oil bitterness evaluation by sensory and chemical analyses.

    Science.gov (United States)

    Favati, Fabio; Condelli, Nicola; Galgano, Fernanda; Caruso, Marisa Carmela

    2013-08-15

    An experimental investigation was performed on blend extra virgin olive oils (EVOOs) from different cultivars and EVOO from different olive monovarieties (Coratina, Leccino, Maiatica, Ogliarola) with the aim to evaluate the possibility of estimating the perceived bitterness intensity by using chemical indices, such as the total phenol content and the compounds responsible for oil bitterness measured spectrophotometrically at 225 nm (K225 value), as bitterness predictors in different EVOO. Therefore, a bitterness predictive model, based on the relationship between the perceived bitterness intensity of the selected stimuli and the chosen chemicals parameters has been built and validated. The results indicated that the oil bitterness intensity could be satisfactorily predicted by using the K225 values of oil samples. Copyright © 2013 Elsevier Ltd. All rights reserved.

  5. Coordinating Chemical and Mineralogical Analyses of Antarctic Dry Valley Sediments as Potential Analogs for Mars

    Science.gov (United States)

    Patel, S. N.; Bishop, J. L.; Englert, P.; Gibson, E. K.

    2015-01-01

    The Antarctic Dry Valleys (ADV) provide a unique terrestrial analog for Martian surface processes as they are extremely cold and dry sedimentary environments. The surface geology and the chemical composition of the Dry Valleys that are similar to Mars suggest the possible presence of these soil-formation processes on Mars. The soils and sediments from Wright Valley, Antarctica were investigated in this study to examine mineralogical and chemical changes along the surface layer in this region and as a function of depth. Surface samples collected near Prospect Mesa and Don Juan Pond of the ADV were analyzed using visible/near-infrared (VNIR) and mid-IR reflectance spectroscopy and major and trace element abundances.

  6. Analysing and Navigating Natural Products Space for Generating Small, Diverse, But Representative Chemical Libraries.

    Science.gov (United States)

    O'Hagan, Steve; Kell, Douglas B

    2018-01-01

    Armed with the digital availability of two natural products libraries, amounting to some 195 885 molecular entities, we ask the question of how we can best sample from them to maximize their "representativeness" in smaller and more usable libraries of 96, 384, 1152, and 1920 molecules. The term "representativeness" is intended to include diversity, but for numerical reasons (and the likelihood of being able to perform a QSAR) it is necessary to focus on areas of chemical space that are more highly populated. Encoding chemical structures as fingerprints using the RDKit "patterned" algorithm, we first assess the granularity of the natural products space using a simple clustering algorithm, showing that there are major regions of "denseness" but also a great many very sparsely populated areas. We then apply a "hybrid" hierarchical K-means clustering algorithm to the data to produce more statistically robust clusters from which representative and appropriate numbers of samples may be chosen. There is necessarily again a trade-off between cluster size and cluster number, but within these constraints, libraries containing 384 or 1152 molecules can be found that come from clusters that represent some 18 and 30% of the whole chemical space, with cluster sizes of, respectively, 50 and 27 or above, just about sufficient to perform a QSAR. By using the online availability of molecules via the Molport system (www.molport.com), we are also able to construct (and, for the first time, provide the contents of) a small virtual library of available molecules that provided effective coverage of the chemical space described. Consistent with this, the average molecular similarities of the contents of the libraries developed is considerably smaller than is that of the original libraries. The suggested libraries may have use in molecular or phenotypic screening, including for determining possible transporter substrates. © 2017 The Authors. Biotechnology Journal Published by Wiley

  7. Statistical Data Analyses of Trace Chemical, Biochemical, and Physical Analytical Signatures

    Energy Technology Data Exchange (ETDEWEB)

    Udey, Ruth Norma [Michigan State Univ., East Lansing, MI (United States)

    2013-01-01

    Analytical and bioanalytical chemistry measurement results are most meaningful when interpreted using rigorous statistical treatments of the data. The same data set may provide many dimensions of information depending on the questions asked through the applied statistical methods. Three principal projects illustrated the wealth of information gained through the application of statistical data analyses to diverse problems.

  8. Development of a general model for determination of thermal conductivity of liquid chemical compounds at atmospheric pressure

    DEFF Research Database (Denmark)

    Gharagheizi, Farhad; Ilani‐Kashkouli, Poorandokht; Sattari, Mehdi

    2013-01-01

    In this communication, a general model for representation/presentation of the liquid thermal conductivity of chemical compounds (mostly organic) at 1 atm pressure for temperatures below normal boiling point and at saturation pressure for temperatures above the normal boiling point is developed...... using the Gene Expression Programming algorithm. Approximately 19,000 liquid thermal conductivity data at different temperatures related to 1636 chemical compounds collected from the DIPPR 801 database are used to obtain the model as well as to assess its predictive capability. The parameters...

  9. The evolution of a LIMS (laboratory information management system). [Chemical analyses at BNFL

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    1992-04-01

    Changes in the world and United Kingdom markets for nuclear fuels during the 1990s have prompted British Nuclear Fuels (BNFL) to maximise cost effectiveness in its Chemical and Metallurgical Services department. A laboratory information management system (LIMS) was introduced in order to keep records of analytical techniques and equipment up to date by coordinating various computer systems. Wherever possible automated systems have replaced traditional, labour intensive techniques. So successful has the LIMS system been, that the team now hopes to expand into expert systems. (UK).

  10. Biological Sampling and Analysis in Sinclair and Dyes Inlets, Washington: Chemical Analyses for 2007 Puget Sound Biota Study

    Energy Technology Data Exchange (ETDEWEB)

    Brandenberger, Jill M.; Suslick, Carolynn R.; Johnston, Robert K.

    2008-10-09

    Evaluating spatial and temporal trends in contaminant residues in Puget Sound fish and macroinvertebrates are the objectives of the Puget Sound Ambient Monitoring Program (PSAMP). In a cooperative effort between the ENVironmental inVESTment group (ENVVEST) and Washington State Department of Fish and Wildlife, additional biota samples were collected during the 2007 PSAMP biota survey and analyzed for chemical residues and stable isotopes of carbon (δ13C) and nitrogen (δ15N). Approximately three specimens of each species collected from Sinclair Inlet, Georgia Basin, and reference locations in Puget Sound were selected for whole body chemical analysis. The muscle tissue of specimens selected for chemical analyses were also analyzed for δ13C and δ15N to provide information on relative trophic level and food sources. This data report summarizes the chemical residues for the 2007 PSAMP fish and macro-invertebrate samples. In addition, six Spiny Dogfish (Squalus acanthias) samples were necropsied to evaluate chemical residue of various parts of the fish (digestive tract, liver, embryo, muscle tissue), as well as, a weight proportional whole body composite (WBWC). Whole organisms were homogenized and analyzed for silver, arsenic, cadmium, chromium, copper, nickel, lead, zinc, mercury, 19 polychlorinated biphenyl (PCB) congeners, PCB homologues, percent moisture, percent lipids, δ13C, and δ15N.

  11. Reversible solid oxide fuel cells (R-SOFCs) with chemically stable proton-conducting oxides

    KAUST Repository

    Bi, Lei; Boulfrad, Samir; Traversa, Enrico

    2015-01-01

    Proton-conducting oxides offer a promising way of lowering the working temperature of solid oxide cells to the intermediate temperate range (500 to 700. °C) due to their better ionic conductivity. In addition, the application of proton

  12. Assessment of toxicological profiles of the municipal wastewater effluents using chemical analyses and bioassays.

    Science.gov (United States)

    Smital, Tvrtko; Terzic, Senka; Zaja, Roko; Senta, Ivan; Pivcevic, Branka; Popovic, Marta; Mikac, Iva; Tollefsen, Knut Erik; Thomas, Kevin V; Ahel, Marijan

    2011-05-01

    The hazardous chemical contamination of untreated wastewater and secondary effluent from the wastewater treatment plant (WWTP) of the city of Zagreb, Croatia was comprehensively characterized using large-volume solid-phase extraction (SPE) and silica gel fractionation, followed by a detailed analysis of the resulting extracts by a combination of chemical and bioassay methods. Over 100 individual contaminants or closely related-contaminant groups were identified by high-resolution gas chromatography/mass spectrometry (GC/MS) and liquid chromatography/quadrupole time-of-flight mass spectrometry (LC-QTOF). Ecotoxicity profiling of the investigated samples, including cytotoxicity, chronic toxicity and EROD activity; inhibition of the multixenobiotic resistance (MXR), genotoxicity and estrogenic potential, revealed the most significant contribution of toxic compounds to be present in polar fractions. Wastewater treatment using conventional activated sludge process reduced the initial toxicity of raw wastewater to various extents, ranging from 28% for algal toxicity to 73.2% for an estrogenic activity. The most efficient toxicity removal was observed for the polar compounds. Copyright © 2010 Elsevier Inc. All rights reserved.

  13. Refractometry and interferometry in chemical analysis; Refractometrie et interferometrie en analyse chimique

    Energy Technology Data Exchange (ETDEWEB)

    Veret, C [Faculte des Sciences de Paris, 75 (France)

    2000-03-01

    In vacuum, an electromagnetic radiation is propagated at a constant velocity. But, when it has to pass through a physical medium, it is submitted to different interactions (for instance: absorption, diffusion, refraction, polarization, dispersion, fluorescence) which lead to a modification of its propagation. In the frequency ranges of the radiation for which the absorption is not very important, the modifications of the propagation velocity of a radiation can bring data on the nature and/or the physical conditions (pressure, temperature) of a medium, whatever its state be: gas, liquid or solid. Thus, the absolute refractive index of a medium in relation to vacuum is defined as the ratio c/v of the propagation velocity c of a monochromatic electromagnetic radiation in vacuum at its velocity v in this medium. The photonic refractometry (field of ultraviolet, visible and infrared radiations) is the set of the measure techniques of the refractive indexes having a role in chemical analysis. The refractometry measures can only be applied to media which are optically transparent. After having described these techniques, the author presents their uses in chemical analysis. (O.M.)

  14. Chemical and microstructural analyses for heavy metals removal from water media by ceramic membrane filtration.

    Science.gov (United States)

    Ali, Asmaa; Ahmed, Abdelkader; Gad, Ali

    2017-01-01

    This study aims to investigate the ability of low cost ceramic membrane filtration in removing three common heavy metals namely; Pb 2+ , Cu 2+ , and Cd 2+ from water media. The work includes manufacturing ceramic membranes with dimensions of 15 by 15 cm and 2 cm thickness. The membranes were made from low cost materials of local clay mixed with different sawdust percentages of 0.5%, 2.0%, and 5.0%. The used clay was characterized by X-ray diffraction (XRD) and X-ray fluorescence analysis. Aqueous solutions of heavy metals were prepared in the laboratory and filtered through the ceramic membranes. The influence of the main parameters such as pH, initial driving pressure head, and concentration of heavy metals on their removal efficiency by ceramic membranes was investigated. Water samples were collected before and after the filtration process and their heavy metal concentrations were determined by chemical analysis. Moreover, a microstructural analysis using scanning electronic microscope (SEM) was performed on ceramic membranes before and after the filtration process. The chemical analysis results showed high removal efficiency up to 99% for the concerned heavy metals. SEM images approved these results by showing adsorbed metal ions on sides of the internal pores of the ceramic membranes.

  15. Hanford Environmental Restoration data validation process for chemical and radiochemical analyses

    International Nuclear Information System (INIS)

    Adams, M.R.; Bechtold, R.A.; Clark, D.E.; Angelos, K.M.; Winter, S.M.

    1993-10-01

    Detailed procedures for validation of chemical and radiochemical data are used to assure consistent application of validation principles and support a uniform database of quality environmental data. During application of these procedures, it was determined that laboratory data packages were frequently missing certain types of documentation causing subsequent delays in meeting critical milestones in the completion of validation activities. A quality improvement team was assembled to address the problems caused by missing documentation and streamline the entire process. The result was the development of a separate data package verification procedure and revisions to the data validation procedures. This has resulted in a system whereby deficient data packages are immediately identified and corrected prior to validation and revised validation procedures which more closely match the common analytical reporting practices of laboratory service vendors

  16. Using vegetable oils and animal fats in Diesel Engines: chemical analyses and engine texts

    International Nuclear Information System (INIS)

    Marmino, I.; Verhelst, S.; Sierens, R.

    2008-01-01

    In this work, some vegetable oils (rapeseed oil, palm oil) and animal fat were tested in a Diesel engine at a range of engine spreads and torque settings, after preheating at 70 0 C. Engine performance, fuel consumption and NOx, unburnt hydrocarbons and soot emissions have been recorded. The results have been compared to those obtained with diesel fuel in the same test conditions. The oils and fats were also analyzed for their physical and chemical properties (viscosity, composition, unsaturation, heating value). NOx emissions were found to be lower for the oils than for the diesel fuel. This, combined with higher HC emissions, can probably be explained through less effective atomization due to the higher viscosity of the oils and fat. On the other hand, soot emissions were found to decrease. [it

  17. The Chemical Diversity of Lantana camara: Analyses of Essential Oil Samples from Cuba, Nepal, and Yemen.

    Science.gov (United States)

    Satyal, Prabodh; Crouch, Rebecca A; Monzote, Lianet; Cos, Paul; Awadh Ali, Nasser A; Alhaj, Mehdi A; Setzer, William N

    2016-03-01

    The aerial parts of Lantana camara L. were collected from three different geographical locations: Artemisa (Cuba), Biratnagar (Nepal), and Sana'a (Yemen). The essential oils were obtained by hydrodistillation and analyzed by gas chromatography/mass spectrometry. A cluster analysis of 39 L. camara essential oil compositions revealed eight major chemotypes: β-caryophyllene, germacrene D, ar-curcumene/zingiberene, γ-curcumen-15-al/epi-β-bisabolol, (E)-nerolidol, davanone, eugenol/alloaromadendrene, and carvone. The sample from Cuba falls into the group dominated by (E)-nerolidol, the sample from Nepal is a davanone chemotype, and the sample from Yemen belongs to the β-caryophyllene chemotype. The chemical composition of L. camara oil plays a role in the biological activity; the β-caryophyllene and (E)-nerolidol chemotypes showed antimicrobial and cytotoxic activities. © 2016 Verlag Helvetica Chimica Acta AG, Zürich.

  18. High temperature conductance mapping for correlation of electrical properties with micron-sized chemical and microstructural features

    Energy Technology Data Exchange (ETDEWEB)

    Hansen, Karin Vels, E-mail: karv@dtu.dk [Department of Energy Conversion and Storage, Technical University of Denmark, Frederiksborgvej 399, DK-4000 Roskilde (Denmark); Norrman, Kion [Department of Energy Conversion and Storage, Technical University of Denmark, Frederiksborgvej 399, DK-4000 Roskilde (Denmark); Jacobsen, Torben [Department of Chemistry, Technical University of Denmark, Kemitorvet Building 207, DK-2800 Lyngby (Denmark)

    2016-11-15

    High temperature AC conductance mapping is a scanning probe technique for resolving local electrical properties in microscopic areas. It is especially suited for detecting poorly conducting phases and for ionically conducting materials such as those used in solid oxide electrochemical cells. Secondary silicate phases formed at the edge of lanthanum strontium manganite microelectrodes are used as an example for correlation of chemical, microstructural and electrical properties with a spatial resolution of 1–2 µm to demonstrate the technique. The measurements are performed in situ in a controlled atmosphere high temperature scanning probe microscope at 650 °C in air. - Highlights: • A high temperature SPM technique for conductance measurements was developed. • Two examples from microelectrodes were used for demonstration. • Conductance mapping at 650 °C revealed poorly conducting secondary phases. • The secondary phases could be correlated with microstructure and chemistry.

  19. Combining hydraulic model, hydrogeomorphological observations and chemical analyses of surface waters to improve knowledge on karst flash floods genesis

    Directory of Open Access Journals (Sweden)

    F. Raynaud

    2015-06-01

    Full Text Available During a flood event over a karst watershed, the connections between surface and ground waters appear to be complex ones. The karst may attenuate surface floods by absorbing water or contribute to the surface flood by direct contribution of karst waters in the rivers (perennial and overflowing springs and by diffuse resurgence along the hillslopes. If it is possible to monitor each known outlet of a karst system, the diffuse contribution is yet difficult to assess. Furthermore, all these connections vary over time according to several factors such as the water content of the soil and underground, the rainfall characteristics, the runoff pathways. Therefore, the contribution of each compartment is generally difficult to assess, and flood dynamics are not fully understood. To face these misunderstandings and difficulties, we analysed surface waters during six recent flood events in the Lirou watershed (a karst tributary of the Lez, in South of France. Because of the specific chemical signature of karst waters, chemical analyses can supply information about water pathways and flood dynamics. Then, we used the dilution law to combine chemical results, flow data and field observations to assess the dynamics of the karst component of the flood. To end, we discussed the surface or karst origin of the waters responsible for the apparent runoff coefficient rise during flash karst flood.

  20. Chemometrical characterization of four italian rice varieties based on genetic and chemical analyses.

    Science.gov (United States)

    Brandolini, Vincenzo; Coïsson, Jean Daniel; Tedeschi, Paola; Barile, Daniela; Cereti, Elisabetta; Maietti, Annalisa; Vecchiati, Giorgio; Martelli, Aldo; Arlorio, Marco

    2006-12-27

    This paper describes a method for achieving qualitative identification of four rice varieties from two different Italian regions. To estimate the presence of genetic diversity among the four rice varieties, we used polymerase chain reaction-randomly amplified polymorphic DNA (PCR-RAPD) markers, and to elucidate whether a relationship exists between the ground and the specific characteristics of the product, we studied proximate composition, fatty acid composition, mineral content, and total antioxidant capacity. Using principal component analysis on genomic and compositional data, we were able to classify rice samples according to their variety and their district of production. This work also examined the discrimination ability of different parameters. It was found that genomic data give the best discrimination based on varieties, indicating that RAPD assays could be useful in discriminating among closely related species, while compositional analyses do not depend on the genetic characters only but are related to the production area.

  1. Proton-Conducting Sulfonated Ionomers by Chemical Modification and Atom Transfer Radical Polymerization

    DEFF Research Database (Denmark)

    Nielsen, Mads Møller

    The cornerstone in this dissertation is made up by three individual assessments of the diversity in the macromolecular landscape that can be obtained by applying relatively few efficient chemical tools. The intention is to gain deeper knowledge on the chemical tuning of proton exchange membranes...... of hydrocarbon macromolecular architectures, PSU with postsulfonated polystyrene (PS) grafts are investigated. Here, IEC is controlled through the degree of substitution, the graft length and DS. The grafting is performed with atom transfer radical polymerization (ATRP). The third assessment is dedicated...... of control by ATRP and click chemistry enables a wide selection of polymer structures with the handles: degree of substitution (DS), polymerization and sulfonation, and blending....

  2. A framework for analysing relationships between chemical composition and crystal structure in metal oxides

    International Nuclear Information System (INIS)

    Thomas, N.W.

    1991-01-01

    A computer program has been written to characterize the coordination polyhedra of metal cations in terms of their volumes and polyhedral elements, i.e. corners, edges and faces. The sharing of these corners, edges and faces between polyhedra is also quantitatively monitored. In order to develop the methodology, attention is focused on ternary oxides containing the Al 3+ ion, whose structures were retrieved from the Inorganic Crystal Structure Database (ICSD). This also permits an objective assessment of the applicability of Pauling's rules. The influence of ionic valence on the structures of these compounds is examined, by calculating electrostatic bond strengths. Although Pauling's second rule is not supported in detail, the calculation of oxygen-ion valence reveals a basic structural requirement, that the average calculated oxygen-ion valence in any ionic oxide structure is equal to 2. The analysis is further developed to define a general method for the prediction of novel chemical compositions likely to adopt a given desired structure. The polyhedral volumes of this structure are calculated, and use is made of standard ionic radii for cations in sixfold coordination. The electroneutrality principle is invoked to take valence considerations into account. This method can be used to guide the development of new compositions of ceramic materials with certain desirable physical properties. (orig.)

  3. Qualitative/Chemical Analyses of Ankaferd Hemostat and Its Antioxidant Content in Synthetic Gastric Fluids

    Directory of Open Access Journals (Sweden)

    Ahmet Koluman

    2016-01-01

    Full Text Available Introduction. Ankaferd hemostat (ABS is the first topical haemostatic agent involving the red blood cell-fibrinogen interactions. The antihemorrhagic efficacy of ABS has been tested in controlled clinical trials. The drug induces the formation of an encapsulated complex protein web with vital erythroid aggregation. The aim of this study is to detect the essential toxicity profile and the antioxidant molecules inside ABS. Methods. The pesticides were analyzed by GC-MS and LC-MS. The determination by ICP-MS after pressure digestion was performed for the heavy metals. HPLC was used for the detection of mycotoxins. Dioxin Response Chemically Activated Luciferase Gene Expression method was used for the dioxin evaluation. TOF-MS and spectra data were evaluated to detect the antioxidants and other molecules. Results. TOF-MS spectra revealed the presence of several antioxidant molecules (including tocotrienols, vitamin E, tryptophan, estriol, galangin, apigenin, oenin, 3,4-divanillyltetrahydrofuran, TBHQ, thymol, BHA, BHT, lycopene, glycyrrhetinic acid, and tomatine, which may have clinical implications in the pharmacobiological actions of ABS. Conclusion. The safety of ABS regarding the presence of heavy metals, pesticides, mycotoxins, GMO and dioxins, and PCBs was demonstrated. Thus the present toxicological results indicated the safety of ABS. The antioxidant content of ABS should be investigated in future studies.

  4. Wet-chemical etching of atom probe tips for artefact free analyses of nanoscaled semiconductor structures.

    Science.gov (United States)

    Melkonyan, D; Fleischmann, C; Veloso, A; Franquet, A; Bogdanowicz, J; Morris, R J H; Vandervorst, W

    2018-03-01

    We introduce an innovative specimen preparation method employing the selectivity of a wet-chemical etching step to improve data quality and success rates in the atom probe analysis of contemporary semiconductor devices. Firstly, on the example of an SiGe fin embedded in SiO 2 we demonstrate how the selective removal of SiO 2 from the final APT specimen significantly improves accuracy and reliability of the reconstructed data. With the oxide removal, we eliminate the origin of shape artefacts, i.e. the formation of a non-hemispherical tip shape, that are typically observed in the reconstructed volume of complex systems. Secondly, using the same approach, we increase success rates to ∼90% for the damage-free, 3D site-specific localization of short (250 nm), vertical Si nanowires at the specimen apex. The impact of the abrupt emitter radius change that is introduced by this specimen preparation method is evaluated as being minor using field evaporation simulation and comparison of different reconstruction schemes. The Ge content within the SiGe fin as well as the 3D boron distribution in the Si NW as resolved by atom probe analysis are in good agreement with TEM/EDS and ToF-SIMS analysis, respectively. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. A chemically stable electrolyte with a novel sandwiched structure for proton-conducting solid oxide fuel cells (SOFCs)

    KAUST Repository

    Bi, Lei

    2013-11-01

    A chemically stable electrolyte structure was developed for proton-conducting SOFCs by using two layers of stable BaZr0.7Pr 0.1Y0.2O3 -δ to sandwich a highly-conductive but unstable BaCe0.8Y0.2O 3 -δ electrolyte layer. The sandwiched electrolyte structure showed good chemical stability in both CO2 and H2O atmosphere, indicating that the BZPY layers effectively protect the inner BCY electrolyte, while the BCY electrolyte alone decomposed completely under the same conditions. Fuel cell prototypes fabricated with the sandwiched electrolyte achieved a relatively high performance of 185 mW cm- 2 at 700 C, with a high electrolyte film conductivity of 4 × 10- 3 S cm- 1 at 600 C. © 2013 Elsevier B.V.

  6. Using trajectory analyses to refine phenotype for genetic association: conduct problems and the serotonin transporter (5HTTLPR).

    Science.gov (United States)

    Sakai, Joseph T; Boardman, Jason D; Gelhorn, Heather L; Smolen, Andrew; Corley, Robin P; Huizinga, David; Menard, Scott; Hewitt, John K; Stallings, Michael C

    2010-10-01

    Conduct disorder is a serious, relatively common disorder of childhood and adolescence. Findings from genetic association studies searching for genetic determinants of the liability toward such behaviors have been inconsistent. One possible explanation for differential results is that most studies define phenotype from a single assessment; for many adolescents conduct problems decrease in severity over time, whereas for others such behaviors persist. Therefore, longitudinal datasets offer the opportunity to refine phenotype. We used Caucasians that were first assessed during adolescence from the National Youth Survey Family Study. Nine waves of data were used to create latent growth trajectories and test for associations between trajectory class and 5HTTLPR genotype. For the full sample, 5HTTLPR was not associated with conduct problem phenotypes. However, the short (s) allele was associated with chronic conduct problems in females; a nominally significant sex by 5HTTLPR genotype interaction was noted. Longitudinal studies provide unique opportunities for phenotypic refinement and such techniques, with large samples, may be useful for phenotypic definition with other study designs, such as whole genome association studies.

  7. Honey roasted peanuts and roasted peanuts from Argentina. Sensorial and chemical analyses

    Directory of Open Access Journals (Sweden)

    Grosso, Nelson R.

    2004-12-01

    Full Text Available The objective of this work was to characterize the chemical and sensory aspects of Honey Roasted (HRP and Roasted Peanuts (RP. These products were evaluated for sensory analysis: overall acceptance using a consumer test and a descriptive analysis using a trained panel. Percentages of protein, oil, carbohydrate and ash was analyzed in HRP and RP. The contents of carbohydrate, oil and protein in HRP were 28.22%, 45.56% and 21.06%, respectively. RP showed higher percentages of lipids and protein and lower percentages of carbohydrate content than HRP. The total energetic value was lower in HRP. Values of 8 (like very much were chosen by a higher number of consumer panelist for HRP while values of 6 (like slightly were found in a higher proportion for RP. The trained panel described 11 attributes: brown color, roughness, roasted peanutty, oxidized, cardboard, sweet, salty, bitter, sour, hardness and crunchiness. The roasted peanutty intensity in RP was higher than in HRP. The intensities of roughness, sweet and salty in HRP were higher than in RP.El objetivo del trabajo fue caracterizar química y sensorialmente al Maní Tostado con Miel (MTM y Maní Tostado (MT. Estos dos productos fueron evaluados sensorialmente analizando su aceptabilidad por parte de consumidores (test de aceptabilidad y sus atributos sensoriales por el uso de un panel de jueces entrenados (prueba descriptiva. Por otra parte se describió la composición química porcentual: porcentajes de proteínas, aceites, hidratos de carbonos y cenizas. Los contenidos de hidratos de carbonos, aceites y proteínas en MTM fueron de 28,22%, 45.56% y 21,06%. MT presentó mayores porcentajes de lípidos y proteínas y menor contenido de hidratos de carbono que MTM. El valor energético total de MTM es levemente menor que en MT. La aceptabilidad de los productos mostró mayor número de consumidores que le asignaron un valor de 8 ( me gusta mucho dentro de una escala hedónica de 9 puntos a MTM y

  8. Tuning anomalous Hall conductivity in L1[sub 0] FePt films by long range chemical ordering

    KAUST Repository

    Chen, M.; Shi, Z.; Xu, W. J.; Zhang, Xixiang; Du, J.; Zhou, S. M.

    2011-01-01

    For L10 FePt films, the anomalous Hall conductivity σ xy=-a σxx-b, where a=a0f(T), b=b 0f(T), and f (T) is the temperature dependence factor of the spontaneous magnetization. With increasing chemical long range ordering S, a0 changes its sign accompanied by a reduction of its magnitude and b0 increases monotonically. The spin-orbit coupling strength is suggested to increase with increasing S. As an approach, the long range chemical ordering can be used to control the anomalous Hall effect in ferromagnetic alloy films. © 2011 American Institute of Physics.

  9. Tuning anomalous Hall conductivity in L1[sub 0] FePt films by long range chemical ordering

    KAUST Repository

    Chen, M.

    2011-02-24

    For L10 FePt films, the anomalous Hall conductivity σ xy=-a σxx-b, where a=a0f(T), b=b 0f(T), and f (T) is the temperature dependence factor of the spontaneous magnetization. With increasing chemical long range ordering S, a0 changes its sign accompanied by a reduction of its magnitude and b0 increases monotonically. The spin-orbit coupling strength is suggested to increase with increasing S. As an approach, the long range chemical ordering can be used to control the anomalous Hall effect in ferromagnetic alloy films. © 2011 American Institute of Physics.

  10. Physicochemical characterization of Capstone depleted uranium aerosols III: morphologic and chemical oxide analyses.

    Science.gov (United States)

    Krupka, Kenneth M; Parkhurst, Mary Ann; Gold, Kenneth; Arey, Bruce W; Jenson, Evan D; Guilmette, Raymond A

    2009-03-01

    The impact of depleted uranium (DU) penetrators against an armored target causes erosion and fragmentation of the penetrators, the extent of which is dependent on the thickness and material composition of the target. Vigorous oxidation of the DU particles and fragments creates an aerosol of DU oxide particles and DU particle agglomerations combined with target materials. Aerosols from the Capstone DU aerosol study, in which vehicles were perforated by DU penetrators, were evaluated for their oxidation states using x-ray diffraction (XRD), and particle morphologies were examined using scanning electron microscopy/energy dispersive spectroscopy (SEM/EDS). The oxidation state of a DU aerosol is important as it offers a clue to its solubility in lung fluids. The XRD analysis showed that the aerosols evaluated were a combination primarily of U3O8 (insoluble) and UO3 (relatively more soluble) phases, though intermediate phases resembling U4O9 and other oxides were prominent in some samples. Analysis of particle residues in the micrometer-size range by SEM/EDS provided microstructural information such as phase composition and distribution, fracture morphology, size distribution, and material homogeneity. Observations from SEM analysis show a wide variability in the shapes of the DU particles. Some of the larger particles were spherical, occasionally with dendritic or lobed surface structures. Others appear to have fractures that perhaps resulted from abrasion and comminution, or shear bands that developed from plastic deformation of the DU material. Amorphous conglomerates containing metals other than uranium were also common, especially with the smallest particle sizes. A few samples seemed to contain small bits of nearly pure uranium metal, which were verified by EDS to have a higher uranium content exceeding that expected for uranium oxides. Results of the XRD and SEM/EDS analyses were used in other studies described in this issue of Health Physics to interpret the

  11. Physicochemical Characterization of Capstone Depleted Uranium Aerosols III: Morphologic and Chemical Oxide Analyses

    International Nuclear Information System (INIS)

    Krupka, Kenneth M.; Parkhurst, MaryAnn; Gold, Kenneth; Arey, Bruce W.; Jenson, Evan D.; Guilmette, Raymond A.

    2009-01-01

    The impact of depleted uranium (DU) penetrators against an armored target causes erosion and fragmentation of the penetrators, the extent of which is dependent on the thickness and material composition of the target. Vigorous oxidation of the DU particles and fragments creates an aerosol of DU oxide particles and DU particle agglomerations combined with target materials. Aerosols from the Capstone DU aerosol study, in which vehicles were perforated by DU penetrators, were evaluated for their oxidation states using X-ray diffraction (XRD) and particle morphologies using scanning electron microscopy/energy dispersive spectrometry (SEM/EDS). The oxidation state of a DU aerosol is important as it offers a clue to its solubility in lung fluids. The XRD analysis showed that the aerosols evaluated were a combination primarily of U3O8 (insoluble) and UO3 (relatively more soluble) phases, though intermediate phases resembling U4O9 and other oxides were prominent in some samples. Analysis of particle residues in the micrometer-size range by SEM/EDS provided microstructural information such as phase composition and distribution, fracture morphology, size distribution, and material homogeneity. Observations from SEM analysis show a wide variability in the shapes of the DU particles. Some of the larger particles appear to have been fractured (perhaps as a result of abrasion and comminution); others were spherical, occasionally with dendritic or lobed surface structures. Amorphous conglomerates containing metals other than uranium were also common, especially with the smallest particle sizes. A few samples seemed to contain small chunks of nearly pure uranium metal, which were verified by EDS to have a higher uranium content exceeding that expected for uranium oxides. Results of the XRD and SEM/EDS analyses were used in other studies described in this issue of The Journal of Health Physics to interpret the results of lung solubility studies and in selecting input parameters for

  12. The reliability of radiochemical and chemical trace analyses in environmental materials

    International Nuclear Information System (INIS)

    Heinonen, Jorma.

    1977-12-01

    After theoretically exploring the factors which influence the quality of analytical data as well as the means by which a sufficient quality can be assured and controlled, schemes of different kinds have been developed and applied in order to demonstrate the analytical quality assurance and control in practice. Methods have been developed for the determination of cesium, bromine and arsenic by neutron activation analysis at the natural ''background'' concentration level in environmental materials. The calibration of methods is described. The methods were also applied on practical routine analysis, the results of which are briefly reviewed. In the case of Ce the precision of a comprehensive calibration was found to vary between 5.2-9.2% as a relative standard deviation, which agrees well with the calculated statistical random error 5.7-8.7%. In the case of Br the method showed a reasonable precision, about 11% on the average, and accuracy. In employing the method to analyze died samples containing Br from 3 to 12 ppm a continuous control of precison was performed. The analysis of As demonstrates the many problems and difficulties associated with environmental analysis. In developing the final method four former intercomparison materials of IAEA were utilized in the calibration. The tests performed revealed a systematic error. In this case a scheme was developed for the continuous control of both precision and accuracy. The results of radiochemical analyses in environmental materials show a reliability somewhat better than that occuring in the determination of stable trace elements. According to a rough classification, 15% of the results of radiochemical analysis show excellent reliability, whereas 60% show a reliability adequate for certain purposes. The remaining 15% are excellent, 60% adequate for some purposes and 30% good-for-nothing. The reasons for often insufficient reliability of results are both organizational and technical. With reasonable effort and

  13. Fast Formation of Conductive Material by Simultaneous Chemical Process for Infilling Through-Silicon Via

    Science.gov (United States)

    Kawakita, Jin; Chikyow, Toyohiro

    2012-06-01

    It is necessary to develop a fast and inexpensive fabrication process of vertical electric wiring by through-silicon via (TSV) technology for advanced three-dimensional semiconductor devices. In this research, a fast-forming conductive composite was successfully developed by simultaneous deposition of conductive organic polymer (polypyrrole) and metal (silver) from the liquid phase, accelerated by photoirradiation. The growth rate of the composite was 38 nm·s-1, which is more than 10 times higher than that of copper by conventional plating. The electric conductivity of the composite was 2.1×104 Ω-1·cm-1, which is on the same level as general metal conductors. In addition, the effects of reaction conditions on the growth rate and the conductivity of the composites were revealed. From these results, the infilling time of the TSV was expected to shorten from the present 2-10 h to 5-10 m.

  14. Results of toxicity tests and chemical analyses conducted on sediments collected from the TNX Outfall Delta Operable Unit, July 1999

    International Nuclear Information System (INIS)

    Specht, W.L.

    2000-01-01

    In order to provide unit specific toxicity data that will be used to address critical uncertainty in the ecological risk assessment (ERA) for the TNX Outfall Delta Operable Unit (TNXOD OU), sediments were collected from eight locations in the Inner Swamp portion of the operable unit and two unit specific background locations. These samples were analyzed for total mercury, total uranium, and sediment toxicity

  15. Occupational allergic contact dermatitis caused by sterile non-latex protective gloves: clinical investigation and chemical analyses.

    Science.gov (United States)

    Pontén, Ann; Hamnerius, Nils; Bruze, Magnus; Hansson, Christer; Persson, Christina; Svedman, Cecilia; Thörneby Andersson, Kirsten; Bergendorff, Ola

    2013-02-01

    An increased frequency of occupational contact hand dermatitis among surgical operating theatre personnel has been noticed. To evaluate patients with occupational contact dermatitis caused by their rubber gloves, and to describe a method for analysing the content of the allergens in the gloves. Patch tests were performed with the baseline series, a rubber chemical series, and the patients' own gloves. A method for analysing 1,3-diphenylguanidine (DPG) and cetylpyridinium chloride in the gloves was developed. Contact allergy to thiuram mix was found in 8 of 16 patients, whereas 12 of 16 patients reacted to DPG. In 7 of 8 patients, contact allergy to cetylpyridinium chloride was found. In the patients' gloves, cetylpyridinium chloride and DPG were detected at higher concentrations on the inside of the gloves than on the outside. Most patients had worked for decades in their present occupations, but their hand dermatitis had only been present for months. Contact allergy to DPG in gloves has been disputed, but, in this study, we were able to confirm the presence of DPG and cetylpyridinium chloride in the causative gloves by using a modified method for the analysis. The presence of these chemicals in gloves caused an increase in occupational contact dermatitis in surgical operating theatre personnel. © 2012 John Wiley & Sons A/S.

  16. Long-term fertilization alters chemically-separated soil organic carbon pools: Based on stable C isotope analyses

    Science.gov (United States)

    Dou, Xiaolin; He, Ping; Cheng, Xiaoli; Zhou, Wei

    2016-01-01

    Quantification of dynamics of soil organic carbon (SOC) pools under the influence of long-term fertilization is essential for predicting carbon (C) sequestration. We combined soil chemical fractionation with stable C isotope analyses to investigate the C dynamics of the various SOC pools after 25 years of fertilization. Five types of soil samples (0-20, 20-40 cm) including the initial level (CK) and four fertilization treatments (inorganic nitrogen fertilizer, IN; balanced inorganic fertilizer, NPK; inorganic fertilizer plus farmyard manure, MNPK; inorganic fertilizer plus corn straw residue, SNPK) were separated into recalcitrant and labile fractions, and the fractions were analysed for C content, C:N ratios, δ13C values, soil C and N recalcitrance indexes (RIC and RIN). Chemical fractionation showed long-term MNPK fertilization strongly increased the SOC storage in both soil layers (0-20 cm = 1492.4 gC m2 and 20-40 cm = 1770.6 gC m2) because of enhanced recalcitrant C (RC) and labile C (LC). The 25 years of inorganic fertilizer treatment did not increase the SOC storage mainly because of the offsetting effects of enhanced RC and decreased LC, whereas no clear SOC increases under the SNPK fertilization resulted from the fast decay rates of soil C.

  17. Landfill mining: Resource potential of Austrian landfills--Evaluation and quality assessment of recovered municipal solid waste by chemical analyses.

    Science.gov (United States)

    Wolfsberger, Tanja; Aldrian, Alexia; Sarc, Renato; Hermann, Robert; Höllen, Daniel; Budischowsky, Andreas; Zöscher, Andreas; Ragoßnig, Arne; Pomberger, Roland

    2015-11-01

    Since the need for raw materials in countries undergoing industrialisation (like China) is rising, the availability of metal and fossil fuel energy resources (like ores or coal) has changed in recent years. Landfill sites can contain considerable amounts of recyclables and energy-recoverable materials, therefore, landfill mining is an option for exploiting dumped secondary raw materials, saving primary sources. For the purposes of this article, two sanitary landfill sites have been chosen for obtaining actual data to determine the resource potential of Austrian landfills. To evaluate how pretreating waste before disposal affects the resource potential of landfills, the first landfill site has been selected because it has received untreated waste, whereas mechanically-biologically treated waste was dumped in the second. The scope of this investigation comprised: (1) waste characterisation by sorting analyses of recovered waste; and (2) chemical analyses of specific waste fractions for quality assessment regarding potential energy recovery by using it as solid recovered fuels. The content of eight heavy metals and the net calorific values were determined for the chemical characterisation tests. © The Author(s) 2015.

  18. Conductivity of graphene in the framework of Dirac model: Interplay between nonzero mass gap and chemical potential

    Science.gov (United States)

    Klimchitskaya, G. L.; Mostepanenko, V. M.; Petrov, V. M.

    2017-12-01

    The complete theory of electrical conductivity of graphene at arbitrary temperature is developed with taking into account mass-gap parameter and chemical potential. Both the in-plane and out-of-plane conductivities of graphene are expressed via the components of the polarization tensor in (2+1)-dimensional space-time analytically continued to the real frequency axis. Simple analytic expressions for both the real and imaginary parts of the conductivity of graphene are obtained at zero and nonzero temperature. They demonstrate an interesting interplay depending on the values of mass gap and chemical potential. In the local limit, several results obtained earlier using various approximate and phenomenological approaches are reproduced, refined, and generalized. The numerical computations of both the real and imaginary parts of the conductivity of graphene are performed to illustrate the obtained results. The analytic expressions for the conductivity of graphene obtained in this paper can serve as a guide in the comparison between different theoretical approaches and between experiment and theory.

  19. Does Anxiety Modify the Risk for, or Severity of, Conduct Problems Among Children With Co-Occurring ADHD: Categorical and Dimensional and Analyses.

    Science.gov (United States)

    Danforth, Jeffrey S; Doerfler, Leonard A; Connor, Daniel F

    2017-08-01

    The goal was to examine whether anxiety modifies the risk for, or severity of, conduct problems in children with ADHD. Assessment included both categorical and dimensional measures of ADHD, anxiety, and conduct problems. Analyses compared conduct problems between children with ADHD features alone versus children with co-occurring ADHD and anxiety features. When assessed by dimensional rating scales, results showed that compared with children with ADHD alone, those children with ADHD co-occurring with anxiety are at risk for more intense conduct problems. When assessment included a Diagnostic and Statistical Manual of Mental Disorders (4th ed.; DSM-IV) diagnosis via the Schedule for Affective Disorders and Schizophrenia for School Age Children-Epidemiologic Version (K-SADS), results showed that compared with children with ADHD alone, those children with ADHD co-occurring with anxiety neither had more intense conduct problems nor were they more likely to be diagnosed with oppositional defiant disorder or conduct disorder. Different methodological measures of ADHD, anxiety, and conduct problem features influenced the outcome of the analyses.

  20. Analyses of a novel SCN5A mutation (C1850S): conduction vs. repolarization disorder hypotheses in the Brugada syndrome

    DEFF Research Database (Denmark)

    Petitprez, Séverine; Jespersen, Thomas; Pruvot, Etienne

    2008-01-01

    S SCN5A mutation. METHODS AND RESULTS: SCN5A was screened for mutations in a male patient with type-1 BrS pattern ECG. Wild-type (WT) and mutant Na(v)1.5 channels were expressed in HEK293 cells. Sodium currents (I(Na)) were analysed using the whole-cell patch-clamp technique at 37 degrees C......AIMS: Brugada syndrome (BrS) is characterized by arrhythmias leading to sudden cardiac death. BrS is caused, in part, by mutations in the SCN5A gene, which encodes the sodium channel alpha-subunit Na(v)1.5. Here, we aimed to characterize the biophysical properties and consequences of a novel Br....... The electrophysiological effects of the mutation were simulated using the Luo-Rudy model, into which the transient outward current (I(to)) was incorporated. A new mutation (C1850S) was identified in the Na(v)1.5 C-terminal domain. In HEK293 cells, mutant I(Na) density was decreased by 62% at -20 mV. Inactivation of mutant...

  1. Reducing thermal conductivity of binary alloys below the alloy limit via chemical ordering

    International Nuclear Information System (INIS)

    Duda, John C; English, Timothy S; Jordan, Donald A; Norris, Pamela M; Soffa, William A

    2011-01-01

    Substitutional solid solutions that exist in both ordered and disordered states will exhibit markedly different physical properties depending on their exact crystallographic configuration. Many random substitutional solid solutions (alloys) will display a tendency to order given the appropriate kinetic and thermodynamic conditions. Such order-disorder transitions will result in major crystallographic reconfigurations, where the atomic basis, symmetry, and periodicity of the alloy change dramatically. Consequently, the dominant scattering mechanism in ordered alloys will be different than that in disordered alloys. In this study, we present a hypothesis that ordered alloys can exhibit lower thermal conductivities than their disordered counterparts at elevated temperatures. To validate this hypothesis, we investigate the phononic transport properties of disordered and ordered AB Lennard-Jones alloys via non-equilibrium molecular dynamics and harmonic lattice dynamics calculations. It is shown that the thermal conductivity of an ordered alloy is the same as the thermal conductivity of the disordered alloy at ∼0.6T melt and lower than that of the disordered alloy above 0.8T melt .

  2. Novel Flexible Transparent Conductive Films with Enhanced Chemical and Electromechanical Sustainability: TiO2 Nanosheet-Ag Nanowire Hybrid.

    Science.gov (United States)

    Sohn, Hiesang; Kim, Seyun; Shin, Weonho; Lee, Jong Min; Lee, Hyangsook; Yun, Dong-Jin; Moon, Kyoung-Seok; Han, In Taek; Kwak, Chan; Hwang, Seong-Ju

    2018-01-24

    Flexible transparent conductive films (TCFs) of TiO 2 nanosheet (TiO 2 NS) and silver nanowire (Ag NW) network hybrid were prepared through a simple and scalable solution-based process. The as-formed TiO 2 NS-Ag NW hybrid TCF shows a high optical transmittance (TT: 97% (90.2% including plastic substrate)) and low sheet resistance (R s : 40 Ω/sq). In addition, the TiO 2 NS-Ag NW hybrid TCF exhibits a long-time chemical/aging and electromechanical stability. As for the chemical/aging stability, the hybrid TCF of Ag NW and TiO 2 NS reveals a retained initial conductivity (ΔR s /R s 4000%) or RuO 2 NS-Ag NW hybrid (ΔR s /R s > 200%). As corroborated by the density functional theory simulation, the superb chemical stability of TiO 2 NS-Ag NW hybrid is attributable to the unique role of TiO 2 NS as a barrier, which prevents Ag NW's chemical corrosion via the attenuated adsorption of sulfidation molecules (H 2 S) on TiO 2 NS. With respect to the electromechanical stability, in contrast to Ag NWs (ΔR/R 0 ∼ 152.9%), our hybrid TCF shows a limited increment of fractional resistivity (ΔR/R 0 ∼ 14.4%) after 200 000 cycles of the 1R bending test (strain: 6.7%) owing to mechanically welded Ag NW networks by TiO 2 NS. Overall, our unique hybrid of TiO 2 NS and Ag NW exhibits excellent electrical/optical properties and reliable chemical/electromechanical stabilities.

  3. Construction of conductive multilayer films of biogenic triangular gold nanoparticles and their application in chemical vapour sensing

    Science.gov (United States)

    Singh, Amit; Chaudhari, Minakshi; Sastry, Murali

    2006-05-01

    Metal nanoparticles are interesting building blocks for realizing films for a number of applications that include bio- and chemical sensing. To date, spherical metal nanoparticles have been used to generate functional electrical coatings. In this paper we demonstrate the synthesis of electrically conductive coatings using biologically prepared gold nanotriangles as the building blocks. The gold nanotriangles are prepared by the reduction of aqueous chloroaurate ions using an extract of the lemongrass plant (Cymbopogon flexuosus) which are thereafter assembled onto a variety of substrates by simple solution casting. The conductivity of the film shows a drastic fall upon mild heat treatment, leading to the formation of electrically conductive thin films of nanoparticles. We have also investigated the possibility of using the gold nanotriangle films in vapour sensing. A large fall in film resistance is observed upon exposure to polar molecules such as methanol, while little change occurs upon exposure to weakly polar molecules such as chloroform.

  4. A combined approach to investigate the toxicity of an industrial landfill's leachate: Chemical analyses, risk assessment and in vitro assays

    International Nuclear Information System (INIS)

    Baderna, D.; Maggioni, S.; Boriani, E.; Gemma, S.; Molteni, M.; Lombardo, A.; Colombo, A.; Bordonali, S.; Rotella, G.; Lodi, M.; Benfenati, E.

    2011-01-01

    Solid wastes constitute an important and emerging problem. Landfills are still one of the most common ways to manage waste disposal. The risk assessment of pollutants from landfills is becoming a major environmental issue in Europe, due to the large number of sites and to the importance of groundwater protection. Furthermore, there is lack of knowledge for the environmental, ecotoxicological and toxicological characteristics of most contaminants contained into landfill leacheates. Understanding leachate composition and creating an integrated strategy for risk assessment are currently needed to correctly face the landfill issues and to make projections on the long-term impacts of a landfill, with particular attention to the estimation of possible adverse effects on human health and ecosystem. In the present study, we propose an integrated strategy to evaluate the toxicity of the leachate using chemical analyses, risk assessment guidelines and in vitro assays using the hepatoma HepG2 cells as a model. The approach was applied on a real case study: an industrial waste landfill in northern Italy for which data on the presence of leachate contaminants are available from the last 11 years. Results from our ecological risk models suggest important toxic effects on freshwater fish and small rodents, mainly due to ammonia and inorganic constituents. Our results from in vitro data show an inhibition of cell proliferation by leachate at low doses and cytotoxic effect at high doses after 48 h of exposure. - Research highlights: → We study the toxicity of leachate from a non-hazardous industrial waste landfill. → We perform chemical analyses, risk assessments and in vitro assays on HepG2 cells. → Risk models suggest toxic effects due to ammonia and inorganic constituents. → In vitro assays show that leachate inhibits cell proliferation at low doses. → Leachate can induce cytotoxic effects on HepG2 cells at high doses.

  5. Fabrication of submicron conducting and chemically functionalized structures from poly(3-octylthiophene) by an electron beam

    International Nuclear Information System (INIS)

    Cai, S.X.; Kanskar, M.; Nabity, J.C.; Keana, J.F.W.; Wybourne, M.N.

    1992-01-01

    The authors present a novel method of using an electron beam to both functionalize and cross-link poly (3-octylthiophene) (P3OT) in a single step to produce submicron scale polymer structures carrying functionalized groups. P3OT is shown to be a negative electron-beam resist with a sensitivity of 15-30 μC cm -2 .The electrical conductivity of doped P3OT wire structures was measured at room temperature and was found to be in the range 4.0-5.9 Ω -1 cm -1 . Electron-beam exposure of P3OT films containing 7 wt % of N-hydroxysuccinimide (NHS) functionalized perfluorophenyl azide 2 resulted in the incorporation of the NHS functional groups in the polymer, as well as cross-linking. The functionalized submicron structures were found to be weakly fluorescent under fluorescein excitation (450-490 nm), but after treatment with a solution of 5-(aminoacetamido)fluorescein in ethanol the structures became strongly fluorescent. 27 refs., 3 figs

  6. Anisotropic electrical conduction and reduction in dangling-bond density for polycrystalline Si films prepared by catalytic chemical vapor deposition

    Science.gov (United States)

    Niikura, Chisato; Masuda, Atsushi; Matsumura, Hideki

    1999-07-01

    Polycrystalline Si (poly-Si) films with high crystalline fraction and low dangling-bond density were prepared by catalytic chemical vapor deposition (Cat-CVD), often called hot-wire CVD. Directional anisotropy in electrical conduction, probably due to structural anisotropy, was observed for Cat-CVD poly-Si films. A novel method to separately characterize both crystalline and amorphous phases in poly-Si films using anisotropic electrical conduction was proposed. On the basis of results obtained by the proposed method and electron spin resonance measurements, reduction in dangling-bond density for Cat-CVD poly-Si films was achieved using the condition to make the quality of the included amorphous phase high. The properties of Cat-CVD poly-Si films are found to be promising in solar-cell applications.

  7. Aliphatic long chain quaternary ammonium compounds analysis by ion-pair chromatography coupled with suppressed conductivity and UV detection in lysing reagents for blood cell analysers.

    Science.gov (United States)

    Giovannelli, D; Abballe, F

    2005-08-26

    A method has been developed which allows simultaneous determination of three linear alkyl trimethylammonium salts. Dodecyltrimethylammonium chloride, tetradecyltrimethylammonium bromide and hexadecyltrimethylammonium chloride are widely used as main active ingredients of lysing reagents for blood cell analyzers which perform white blood cells differential determination into two or more sub-populations by impedance analysis. The ion-pair on styrene-divinyl benzene chromatographic phase looks like a suitable, reliable and long term stable tool for separation of such quaternary compounds. The detection based on suppressed conductivity was chosen because of the lack of significance chromophores. A micromembrane suppressor device compatible with high solvent concentration (up to 80%) was used in order to minimize the conductivity background before the detection. In the present work we show how the chemical post column derivatization makes the alkyl chain detectable also by UV direct detection at 210 nm.

  8. Characterization of electro-conductive fabrics prepared by in situ chemical and electrochemical polymerization of pyrrole onto polyester fabric

    Energy Technology Data Exchange (ETDEWEB)

    Maiti, Syamal; Das, Dipayan; Sen, Kushal, E-mail: kushal@textile.iitd.ernet.in

    2014-09-15

    Highlights: • Surface resistivity of the fabrics decreased rapidly with an increase in add-on. • Add-on and resistivity were not correlated below a resistivity value of about 200 Ω. • Higher add-on but lower surface roughness resulted in lower surface resistivity. • The voltage–current and voltage–temperature behaviours were found to be non-linear. • Electro-conductive fabric exhibited 98% electromagnetic shielding efficiency. - Abstract: This paper reports a study on electro-conductive fabrics prepared by a combined in situ chemical and electrochemical polymerization of pyrrole. Specific observations are made to establish the roles of add-on and surface roughness on the surface resistivity of the electro-conductive fabrics. The performance characteristics of the fabrics are reported in terms of electrical conductivity, voltage–current and voltage–temperature characteristics and electromagnetic interference (EMI) shielding capability. The surface resistivity of the fabric was found to be as low as 11.79 Ω. The voltage–current profile of the fabric is observed to be non-ohmic as well as the voltage–temperature curve is found to be exponential. The EMI shielding efficiency of the fabric was found to be about 98%.

  9. Characterization of electro-conductive fabrics prepared by in situ chemical and electrochemical polymerization of pyrrole onto polyester fabric

    International Nuclear Information System (INIS)

    Maiti, Syamal; Das, Dipayan; Sen, Kushal

    2014-01-01

    Highlights: • Surface resistivity of the fabrics decreased rapidly with an increase in add-on. • Add-on and resistivity were not correlated below a resistivity value of about 200 Ω. • Higher add-on but lower surface roughness resulted in lower surface resistivity. • The voltage–current and voltage–temperature behaviours were found to be non-linear. • Electro-conductive fabric exhibited 98% electromagnetic shielding efficiency. - Abstract: This paper reports a study on electro-conductive fabrics prepared by a combined in situ chemical and electrochemical polymerization of pyrrole. Specific observations are made to establish the roles of add-on and surface roughness on the surface resistivity of the electro-conductive fabrics. The performance characteristics of the fabrics are reported in terms of electrical conductivity, voltage–current and voltage–temperature characteristics and electromagnetic interference (EMI) shielding capability. The surface resistivity of the fabric was found to be as low as 11.79 Ω. The voltage–current profile of the fabric is observed to be non-ohmic as well as the voltage–temperature curve is found to be exponential. The EMI shielding efficiency of the fabric was found to be about 98%

  10. Microstructural and conductivity changes induced by annealing of ZnO:B thin films deposited by chemical vapour deposition

    International Nuclear Information System (INIS)

    David, C; Girardeau, T; Paumier, F; Eyidi, D; Guerin, P; Marteau, M; Lacroix, B; Papathanasiou, N; Tinkham, B P

    2011-01-01

    Zinc oxide (ZnO) thin films have attracted much attention in recent years due to progress in crystal growth for a large variety of technological applications including optoelectronics and transparent electrodes in solar cells. Boron (B)-doped ZnO thin films are deposited by low pressure chemical vapour deposition (LPCVD) on Si(100). These films exhibit a strong (002) texture with a pyramidal grain structure. The ZnO films were annealed after growth; the annealing temperature and the atmosphere appear to strongly impact the layer conductivity. This work will first present the modification of the physical properties (carrier concentration, mobility) extracted from the simulation of layer reflection in the infrared range. At low annealing temperatures the mobility increases slightly before decreasing drastically above a temperature close to 250 deg. C. The chemical and structural evolution (XPS, x-ray diffraction) of the films was also studied to identify the relationship between microstructural modifications and the variations observed in the film conductivity. An in situ XRD study during annealing has been performed under air and low pressure conditions. As observed for electrical properties, the microstructural modifications shift to higher temperatures for vacuum annealing.

  11. Using US EPA’s Chemical Safety for Sustainability’s Comptox Chemistry Dashboard and Tools for Bioactivity, Chemical and Toxicokinetic Modeling Analyses (Course at 2017 ISES Annual Meeting)

    Science.gov (United States)

    Title: Using US EPA’s Chemical Safety for Sustainability’s Comptox Chemistry Dashboard and Tools for Bioactivity, Chemical and Toxicokinetic Modeling Analyses • Class format: half-day (4 hours) • Course leader(s): Barbara A. Wetmore and Antony J. Williams,...

  12. Investigation of the Effect of Mixing Methods and Chemical Treatments on the Conductivity of the CNT/PLA Based Composites

    Science.gov (United States)

    Talwar, Brijpal Singh

    methods: HNO3 acid functionalization, 3:1 ratio HNO 3 + H2SO4 acid (stronger) functionalization and N2 plasma functionalization. To check the effect of amine binding molecules, HNO3 acid functionalized CNTs are treated with a mixture of para-phenylenediamine and aniline in an acidic solution. These chemically treated CNTs are then mixed with PLA to form composites. CPC fibers are drawn using the solvent-cast printing method. These fibers are tested for their electrical conductivity using the two-probe resistivity measurement method. Maximum electrical conductivity was observed in the 5wt. % CNT concentration samples at 3.97 S/m and 25.16 S/m for CPC fibers obtained via the solution blend and the extrusion methods, respectively. In the case of the functionalized CNTs, conductivity measurements show a negative effect of functionalization on the electrical properties of the CPC. While, the amine treated CNT/PLA CPC fibers show better conductivity at 4.2 S/m when compared to the untreated CNT/PLA samples manufactured using the solution mixing method. Finally, one-dimensional (1D) structures like fibres and 2D, 3D structures like single and multi-layer scaffolds were fabricated using the solvent-cast printing technique with the above manufactured CPC solutions in DCM as inks. Such conductive microstructures find their application in the electronic industry and in micro-scale systems such as pollution detection in natural environments, tissue engineering, mechanical sensors and smart devices.

  13. Influence of both ion bombardment and chemical treatment processes on the electrical conductivity of PVC/poly aniline composites

    International Nuclear Information System (INIS)

    Gad, E.A.M.; Ashour, A.H.; Abdel-Hamid, H.M.; Sayed, W.M.

    1999-01-01

    In this article the changes in the electrical conductivity of PVC/poly aniline composites, as temperature consecutively increases, have been measured. The measurement were taken with correspondence to a control series of the composites under two processes:A. Composite samples bombarded with Ar + ions with fluence 2.44 x 10 13 beam ions /cm 2 ., sec 4 of 4 ke V beam energy where argon atoms can induce defects in the surface layer take place. Composite samples treated chemically with concentrated H 2 SO 4 as dopant which reacts with nitrogen atom in aniline. The measurements were also, done with the composites as the ratio of poly(aniline) stepped upward

  14. Taxometric analyses and predictive accuracy of callous-unemotional traits regarding quality of life and behavior problems in non-conduct disorder diagnoses.

    Science.gov (United States)

    Herpers, Pierre C M; Klip, Helen; Rommelse, Nanda N J; Taylor, Mark J; Greven, Corina U; Buitelaar, Jan K

    2017-07-01

    Callous-unemotional (CU) traits have mainly been studied in relation to conduct disorder (CD), but can also occur in other disorder groups. However, it is unclear whether there is a clinically relevant cut-off value of levels of CU traits in predicting reduced quality of life (QoL) and clinical symptoms, and whether CU traits better fit a categorical (taxonic) or dimensional model. Parents of 979 youths referred to a child and adolescent psychiatric clinic rated their child's CU traits on the Inventory of Callous-Unemotional traits (ICU), QoL on the Kidscreen-27, and clinical symptoms on the Child Behavior Checklist. Experienced clinicians conferred DSM-IV-TR diagnoses of ADHD, ASD, anxiety/mood disorders and DBD-NOS/ODD. The ICU was also used to score the DSM-5 specifier 'with limited prosocial emotions' (LPE) of Conduct Disorder. Receiver operating characteristic (ROC) analyses revealed that the predictive accuracy of the ICU and LPE regarding QoL and clinical symptoms was poor to fair, and similar across diagnoses. A clinical cut-off point could not be defined. Taxometric analyses suggested that callous-unemotional traits on the ICU best reflect a dimension rather than taxon. More research is needed on the impact of CU traits on the functional adaptation, course, and response to treatment of non-CD conditions. Copyright © 2017 Elsevier Ireland Ltd. All rights reserved.

  15. Computational fluid dynamics analyses of lateral heat conduction, coolant azimuthal mixing and heat transfer predictions in a BR2 fuel assembly geometry

    International Nuclear Information System (INIS)

    Tzanos, C.P.; Dionne, B.

    2011-01-01

    To support the analyses related to the conversion of the BR2 core from highly-enriched (HEU) to low-enriched (LEU) fuel, the thermal-hydraulics codes PLTEMP and RELAP-3D are used to evaluate the safety margins during steady-state operation (PLTEMP), as well as after a loss-of-flow, loss-of-pressure, or a loss of coolant event (RELAP). In the 1-D PLTEMP and RELAP simulations, conduction in the azimuthal and axial directions is not accounted. The very good thermal conductivity of the cladding and the fuel meat and significant temperature gradients in the lateral directions (axial and azimuthal directions) could lead to a heat flux distribution that is significantly different than the power distribution. To evaluate the significance of the lateral heat conduction, 3-D computational fluid dynamics (CFD) simulations, using the CFD code STAR-CD, were performed. Safety margin calculations are typically performed for a hot stripe, i.e., an azimuthal region of the fuel plates/coolant channel containing the power peak. In a RELAP model, for example, a channel between two plates could be divided into a number of RELAP channels (stripes) in the azimuthal direction. In a PLTEMP model, the effect of azimuthal power peaking could be taken into account by using engineering factors. However, if the thermal mixing in the azimuthal direction of a coolant channel is significant, a stripping approach could be overly conservative by not taking into account this mixing. STAR-CD simulations were also performed to study the thermal mixing in the coolant. Section II of this document presents the results of the analyses of the lateral heat conduction and azimuthal thermal mixing in a coolant channel. Finally, PLTEMP and RELAP simulations rely on the use of correlations to determine heat transfer coefficients. Previous analyses showed that the Dittus-Boelter correlation gives significantly more conservative (lower) predictions than the correlations of Sieder-Tate and Petukhov. STAR-CD 3-D

  16. Analyses of production tests and MDT tests conducted in Mallik and Alaska methane hydrate reservoirs : what can we learn from these well tests?

    Energy Technology Data Exchange (ETDEWEB)

    Kurihara, M.; Funatsu, K.; Ouchi, H. [Japan Oil Engineering Co., Tokyo (Japan); Masuda, Y. [Tokyo Univ., Tokyo (Japan). School of Engineering; Yamamoto, K. [Japan Oil, Gas and Metals National Corp., Tokyo (Japan); Narita, H. [National Inst. of Advanced Industrial Science and Technology, Tokyo (Japan); Dallimore, S.R. [Natural Resources Canada, Ottawa, ON (Canada). Geological Survey of Canada; Collett, T.S. [United States Geological Survey, Reston, VA (United States); Hancock, S.H. [APA Petroleum Engineering Ltd., Calgary, AB (Canada)

    2008-07-01

    This paper described a series of pressure drawdown tests conducted to evaluate a modular formation dynamics tester (MDT) wireline tool. The tests were conducted at the Mallik methane hydrate (MH) reservoir as well as in MH reservoirs in Alaska over a period of several years. Production tests were also conducted to evaluate depressurization methods, and measure production and bottomhole pressure (BHP) below known MH stability pressures in order to estimate permeability and MH dissociation radius properties. The results of the tests were then history-matched using a numerical simulator. An analysis of the simulation study showed that the MDT tests were useful in estimating initial effective permeability levels in the presence of MH. However, wellbore storage erased important data used to indicate the radius of MH dissociation and effective permeability after partial MH dissociation. The study also showed that steady flow conditions must be established before obtaining solutions from history-matched production tests. Parameters accurately estimated using the MDT and production tests were outlined, and suggestions for future designs and analyses for MH reservoirs were presented. 14 refs., 7 tabs., 17 figs.

  17. Estimation of time-variable fast flow path chemical concentrations for application in tracer-based hydrograph separation analyses

    Science.gov (United States)

    Kronholm, Scott C.; Capel, Paul D.

    2016-01-01

    Mixing models are a commonly used method for hydrograph separation, but can be hindered by the subjective choice of the end-member tracer concentrations. This work tests a new variant of mixing model that uses high-frequency measures of two tracers and streamflow to separate total streamflow into water from slowflow and fastflow sources. The ratio between the concentrations of the two tracers is used to create a time-variable estimate of the concentration of each tracer in the fastflow end-member. Multiple synthetic data sets, and data from two hydrologically diverse streams, are used to test the performance and limitations of the new model (two-tracer ratio-based mixing model: TRaMM). When applied to the synthetic streams under many different scenarios, the TRaMM produces results that were reasonable approximations of the actual values of fastflow discharge (±0.1% of maximum fastflow) and fastflow tracer concentrations (±9.5% and ±16% of maximum fastflow nitrate concentration and specific conductance, respectively). With real stream data, the TRaMM produces high-frequency estimates of slowflow and fastflow discharge that align with expectations for each stream based on their respective hydrologic settings. The use of two tracers with the TRaMM provides an innovative and objective approach for estimating high-frequency fastflow concentrations and contributions of fastflow water to the stream. This provides useful information for tracking chemical movement to streams and allows for better selection and implementation of water quality management strategies.

  18. Report on hydro-mechanical and chemical-mineralogical analyses of the bentonite buffer in Canister Retrieval Test

    Energy Technology Data Exchange (ETDEWEB)

    Dueck, Ann; Johannesson, Lars-Erik; Kristensson, Ola; Olsson, Siv [Clay Technology AB (Sweden)

    2011-12-15

    The effect of five years of exposure to repository-like conditions on compacted Wyoming bentonite was determined by comparing the hydraulic, mechanical, and mineralogical properties of samples from the bentonite buffer of the Canister Retrieval Test (CRT) with those of reference material. The CRT, located at the Swedish Aspo Hard Rock Laboratory (HRL), was a full-scale field experiment simulating conditions relevant for the Swedish KBS-3 concept for disposal of high-level radioactive waste in crystalline host rock. The compacted bentonite, surrounding a copper canister equipped with heaters, had been subjected to heating at temperatures up to 95 deg C and hydration by natural Na-Ca-Cl type groundwater for almost five years at the time of retrieval. Under the thermal and hydration gradients that prevailed during the test, sulfate in the bentonite was redistributed and accumulated as anhydrite close to the canister. The major change in the exchangeable cation pool was a loss in Mg in the outer parts of the blocks, suggesting replacement of Mg mainly by Ca along with the hydration with groundwater. Close to the copper canister, small amounts of Cu were incorporated in the bentonite. A reduction of strain at failure was observed in the innermost part of the bentonite buffer, but no influence was seen on the shear strength. No change of the swelling pressure was observed, while a modest decrease in hydraulic conductivity was found for the samples with the highest densities. No coupling was found between these changes in the hydro-mechanical properties and the montmorillonite . the X-ray diffraction characteristics, the cation exchange properties, and the average crystal chemistry of the Na-converted < 1 {mu}m fractions provided no evidence of any chemical/structural changes in the montmorillonite after the 5-year hydrothermal test.

  19. Chemical data and statistical analyses from a uranium hydrogeochemical survey of the Rio Ojo Caliente drainage basin, New Mexico. Part I. Water

    International Nuclear Information System (INIS)

    Wenrich-Verbeek, K.J.; Suits, V.J.

    1979-01-01

    This report presents the chemical analyses and statistical evaluation of 62 water samples collected in the north-central part of New Mexico near Rio Ojo Caliente. Both spring and surface-water samples were taken throughout the Rio Ojo Caliente drainage basin above and a few miles below the town of La Madera. A high U concentration (15 μg/l) found in the water of the Rio Ojo Caliente near La Madera, Rio Arriba County, New Mexico, during a regional sampling-technique study in August 1975 by the senior author, was investigated further in May 1976 to determine whether stream waters could be effectively used to trace the source of a U anomaly. A detailed study of the tributaries to the Rio Ojo Caliente, involving 29 samples, was conducted during a moderate discharge period, May 1976, so that small tributaries would contain water. This study isolated Canada de la Cueva as the tributary contributing the anomalous U, so that in May 1977, an extremely low discharge period due to the 1977 drought, an additional 33 samples were taken to further define the anomalous area. 6 references, 3 figures, 6 tables

  20. Crystallographic and single-particle analyses of native- and nucleotide-bound forms of the cystic fibrosis transmembrane conductance regulator (CFTR) protein.

    Science.gov (United States)

    Awayn, N H; Rosenberg, M F; Kamis, A B; Aleksandrov, L A; Riordan, J R; Ford, R C

    2005-11-01

    Cystic fibrosis, one of the major human inherited diseases, is caused by defects in the CFTR (cystic fibrosis transmembrane conductance regulator), a cell-membrane protein. CFTR acts as a chloride channel which can be opened by ATP. Low-resolution structural studies of purified recombinant human CFTR are described in the present paper. Localization of the C-terminal decahistidine tag in CFTR was achieved by Ni2+-nitriloacetate nanogold labelling, followed by electron microscopy and single-particle analysis. The presence of the gold label appears to improve the single-particle-alignment procedure. Projection structures of CFTR from two-dimensional crystals analysed by electron crystallography displayed two alternative conformational states in the presence of nucleotide and nanogold, but only one form of the protein was observed in the quiescent (nucleotide-free) state.

  1. Method of chemical analysis of silicate rocks (1962); Methode d'analyse chimique des roches silicatees (1962)

    Energy Technology Data Exchange (ETDEWEB)

    Pouget, R [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

    1962-07-01

    A rapid method of analysis for the physical and chemical determination of the major constituents of silicate rocks is described. Water losses at 100 deg. C and losses of volatile elements at 1000 deg. C are estimated after staying in oven for these temperatures, or by mean of a thermo-balance. The determination of silica is made by a double insolubilization with hydrochloric acid on attack solution with sodium carbonate; total iron and aluminium, both with calcium and magnesium, after ammoniacal precipitation of Fe and Al, are determined on the filtration product of silica by titrimetry-photometry of their complexes with EDTA. The alkalis Na and K by flame spectrophotometry, Mn by colorimetry of the permanganate, and Ti by mean of his complex with H{sub 2}O{sub 2}, are determined on fluosulfuric attack solution. Phosphorus is determined by his complex with 'molybdenum blue' on a fluoro-nitro-boric attack solution; iron is estimated by potentiometry, with the help of bichromate on hydrofluoric solution. (author) [French] Une methode d'analyse rapide est decrite pour la determination physico-chimique des constituants principaux des roches silicatees. Les pertes en eau a 100 deg. C et en matieres volatiles a 1000 deg. C sont evaluees apres passage au four a ces temperatures, ou a l'aide d'une thermobalance. La determination de la silice se fait par double insolubilisation a l'acide chlorhydrique, sur une attaque au carbonate de sodium; le fer total et l'aluminium ainsi que le calcium et le magnesium, apres precipitation a l'ammoniaque des deux premiers metaux, sont determines sur le filtrat de la silice par titrimetrie-photometrie de leurs complexes avec l'E.D.T.A. Les alcalins sodium et potassium par spectrophotometrie de flamme, le manganese par colorimetrie du permanganate, le titane a l'aide de son complexe avec l'eau oxygenee, sont determines sur une attaque fluosulfurique. Le phosphore est determine par son complexe du 'bleu de molybdene' sur une attaque fluo

  2. Estimation of Corn Yield and Soil Nitrogen via Soil Electrical Conductivity Measurement Treated with Organic, Chemical and Biological Fertilizers

    Directory of Open Access Journals (Sweden)

    H. Khalilzade

    2016-02-01

    Full Text Available Introduction Around the world maize is the second crop with the most cultivated areas and amount of production, so as the most important strategic crop, have a special situation in policies, decision making, resources and inputs allocation. On the other side, negative environmental consequences of intensive consumption of agrochemicals resulted to change view concerning food production. One of the most important visions is sustainable production of enough food plus attention to social, economic and environmental aspects. Many researchers stated that the first step to achieve this goal is optimization and improvement of resources use efficiencies. According to little knowledge on relation between soil electrical conductivity and yield of maize, beside the environmental concerns about nitrogen consumption and need to replace chemical nitrogen by ecological inputs, this study designed and aimed to evaluate agroecological characteristics of corn and some soil characteristics as affected by application of organic and biological fertilizers under field conditions. Materials and Methods In order to probing the possibility of grain yield and soil nitrogen estimation via measurement of soil properties, a field experiment was conducted during growing season 2010 at Research Station, Ferdowsi University of Mashhad, Iran. A randomized complete block design (RCBD with three replications was used. Treatments included: 1- manure (30 ton ha-1, 2-vermicompost (10 ton ha-1, 3- nitroxin (containing Azotobacter sp. and Azospirillum sp., inoculation was done according to Kennedy et al., 4- nitrogen as urea (400 kg ha-1 and 5- control (without fertilizer. Studied traits were soil pH, soil EC, soil respiration rate, N content of soil and maize yield. Soil respiration rate was measured using equation 1: CO2= (V0- V× N×22 Equation 1 In which V0 is the volume of consumed acid for control treatment titration, V is of the volume of consumed acid for sample treatment

  3. Treatment of spices with ionizing radiation - chemical, organoleptical, microbiological and toxicological analyses. Pt. 1. Behandlung von Gewuerzen mit ionisierenden Strahlen - chemische, organoleptische, mikrobiologische und toxikologische Aspekte

    Energy Technology Data Exchange (ETDEWEB)

    Schuettler, C; Boegl, W

    1984-01-01

    In a study of the relevant literature the results of tests on 30 radiation treated spices were evaluated. The tests contain chemical, organoleptical, microbiological and toxicological analyses. Most of the spices were treated with gamma radiation from cobalt-60 sources with doses up to 60 kGy.

  4. Do code of conduct audits improve chemical safety in garment factories? Lessons on corporate social responsibility in the supply chain from Fair Wear Foundation.

    Science.gov (United States)

    Lindholm, Henrik; Egels-Zandén, Niklas; Rudén, Christina

    2016-10-01

    In managing chemical risks to the environment and human health in supply chains, voluntary corporate social responsibility (CSR) measures, such as auditing code of conduct compliance, play an important role. To examine how well suppliers' chemical health and safety performance complies with buyers' CSR policies and whether audited factories improve their performance. CSR audits (n = 288) of garment factories conducted by Fair Wear Foundation (FWF), an independent non-profit organization, were analyzed using descriptive statistics and statistical modeling. Forty-three per cent of factories did not comply with the FWF code of conduct, i.e. received remarks on chemical safety. Only among factories audited 10 or more times was there a significant increase in the number of factories receiving no remarks. Compliance with chemical safety requirements in garment supply chains is low and auditing is statistically correlated with improvements only at factories that have undergone numerous audits.

  5. Do code of conduct audits improve chemical safety in garment factories? Lessons on corporate social responsibility in the supply chain from Fair Wear Foundation

    Science.gov (United States)

    2016-01-01

    Background In managing chemical risks to the environment and human health in supply chains, voluntary corporate social responsibility (CSR) measures, such as auditing code of conduct compliance, play an important role. Objectives To examine how well suppliers’ chemical health and safety performance complies with buyers’ CSR policies and whether audited factories improve their performance. Methods CSR audits (n = 288) of garment factories conducted by Fair Wear Foundation (FWF), an independent non-profit organization, were analyzed using descriptive statistics and statistical modeling. Results Forty-three per cent of factories did not comply with the FWF code of conduct, i.e. received remarks on chemical safety. Only among factories audited 10 or more times was there a significant increase in the number of factories receiving no remarks. Conclusions Compliance with chemical safety requirements in garment supply chains is low and auditing is statistically correlated with improvements only at factories that have undergone numerous audits. PMID:27611103

  6. Microstructures, Mechanical Properties and Thermal Conductivities of W-0.5 wt.%TiC Alloys Prepared via Ball Milling and Wet Chemical Method

    Science.gov (United States)

    Lang, Shaoting; Yan, Qingzhi; Sun, Ningbo; Zhang, Xiaoxin; Ge, Changchun

    2017-10-01

    Two kinds of W-0.5 wt.%TiC alloys were prepared, one by ball milling and the other by the wet chemical method. For comparison, pure tungsten powders were chemically prepared and sintered by the same process. The microstructures, mechanical properties and thermal conductivities of the prepared samples were characterized. It has been found that the wet chemical method resulted in finer sizes and more uniform distribution of TiC particles in the sintered tungsten matrix than the ball milling method. The W-TiC alloy prepared by the wet chemical method achieved the highest bending strength (1065.72 MPa) among the samples. Further, it also exhibited obviously higher thermal conductivities in the temperature range of room temperature to 600°C than did the W-TiC alloy prepared by ball milling, but the differences in their thermal conductivities could be ignored in the range of 600-800°C.

  7. The calculation of electron chemical potential and ion charge state and their influence on plasma conductivity in electrical explosion of metal wire

    International Nuclear Information System (INIS)

    Shi, Zongqian; Wang, Kun; Li, Yao; Shi, Yuanjie; Wu, Jian; Jia, Shenli

    2014-01-01

    The electron chemical potential and ion charge state (average ion charge and ion distribution) are important parameters in calculating plasma conductivity in electrical explosion of metal wire. In this paper, the calculating method of electron chemical potential and ion charge state is discussed at first. For the calculation of electron chemical potential, the ideal free electron gas model and Thomas-Fermi model are compared and analyzed in terms of the coupling constant of plasma. The Thomas-Fermi ionization model, which is used to calculate ion charge state, is compared with the method based on Saha equation. Furthermore, the influence of electron degenerated energy levels and ion excited states in Saha equation on the ion charge state is also analyzed. Then the influence of different calculating methods of electron chemical potential and ion charge state on plasma conductivity is discussed by applying them in the Lee-More conductivity model

  8. Chemical Dynamics and Critical Phenomena: Electrical Conductivity and Reactivity of Benzyl Bromide in Triethylamine+Water Near its Consolute Point

    Science.gov (United States)

    Specker, Christopher D.; Ellis, Joel M.; Baird, James K.

    2007-06-01

    The binary liquid mixture of triethylamine+water has a lower consolute point at a critical composition of 32.27mass% triethylamine. Starting at a temperature within the one-phase region, the electrical conductivity of a sample of this mixture was measured and found to increase smoothly with increasing temperature before falling sharply at 291.24K (18.09°C). Since opalescence was visible at this temperature, it was identified with the critical solution temperature of the binary mixture. A solution of 90 μL of benzyl bromide dissolved in 90mL of 32.27mass% triethylamine+water was prepared, and the resulting Menschutkin reaction between benzyl bromide and triethylamine was allowed to come to equilibrium. The electrical conductivity of this equilibrium mixture was measured in the one-phase region and was found to increase smoothly with increasing temperature before rising sharply at 291.55K (18.40°C). This temperature was identified as the critical temperature of the ternary. The rate of approach of the ternary mixture to chemical equilibrium was also measured and shown to be governed by a first-order rate law. The temperature dependence of the rate coefficient followed the Arrhenius equation up to a temperature of about 290.74K (17.59°C). Above this temperature, the rate coefficient fell by as much as 22% below the value predicted by extrapolation of the Arrhenius equation. This suppression in the rate reaction in the vicinity of the critical temperature can be interpreted as evidence for the existence of critical slowing down.

  9. The use of microbial and chemical analyses to characterize the variations in fouling profile of seawater reverse osmosis (SWRO) membrane

    KAUST Repository

    Manes, Carmem Lara De O; Khan, Muhammad; Molina, Veró nica Garcí a; Croue, Jean-Philippe

    2013-01-01

    and microbiological composition. The overall assessment of chemical parameters revealed that fouling layers were mainly composed by bio and organic material (proteins and lipids). Ca and Fe were found to be the most abundant elements having an increasing concentration

  10. Chemical analyses of waters from geysers, hot springs, and pools in Yellowstone National Park, Wyoming from 1974 to 1978

    Energy Technology Data Exchange (ETDEWEB)

    Thompson, J.M.; Yadav, S.

    1979-01-01

    Waters from geysers, hot springs, and pools of Yellowstone National Park have been analyzed. We report 422 complete major ion analyses from 330 different locations of geysers, hot springs, and pools, collected from 1974 to 1978. Many of the analyses from Upper, Midway, Lower, and Norris Geyser Basin are recollections of features previously reported.

  11. Development and the physical, chemical, microbiological and sensory analyses of red pepper seasoned with parmesan cheese - doi: 10.4025/actascitechnol.v35i3.12794

    Directory of Open Access Journals (Sweden)

    Gisele Teixeira de Souza Sora

    2013-06-01

    Full Text Available Pickles comprising red pepper seasoned with Parmesan cheese has been developed as a new type of product developed by family cottage industries. Two formulations were prepared, or rather, with and without the preservative potassium sorbate, which underwent several physical, chemical, microbiological and sensory analyses. Physical and chemical analyses were undertaken for acidity, pH and °Brix; microbiological analyses for total heat-tolerant coliforms, Salmonella sp, molds, yeasts; sensory aspects such as physical features, aroma, flavor and texture, coupled to purchase intention among tasters were investigated. Both formulations comprised physical, chemical and microbiological parameters within standards. Sensory evaluation showed satisfactory results and research on purchase intention showed approximately 80% acceptability. Results from physical, chemical and microbiological tests showed that pickled pepper seasoned with Parmesan cheese may be prepared with citric acid as a preservative. Sensory evaluation and purchase intention indicate a real production and sale possibility of pickled peppers seasoned with Parmesan cheese by family cottage industries.  

  12. Development of a fully automated open-column chemical-separation system—COLUMNSPIDER—and its application to Sr-Nd-Pb isotope analyses of igneous rock samples

    Science.gov (United States)

    Miyazaki, Takashi; Vaglarov, Bogdan Stefanov; Takei, Masakazu; Suzuki, Masahiro; Suzuki, Hiroaki; Ohsawa, Kouzou; Chang, Qing; Takahashi, Toshiro; Hirahara, Yuka; Hanyu, Takeshi; Kimura, Jun-Ichi; Tatsumi, Yoshiyuki

    A fully automated open-column resin-bed chemical-separation system, named COLUMNSPIDER, has been developed. The system consists of a programmable micropipetting robot that dispenses chemical reagents and sample solutions into an open-column resin bed for elemental separation. After the initial set up of resin columns, chemical reagents, and beakers for the separated chemical components, all separation procedures are automated. As many as ten samples can be eluted in parallel in a single automated run. Many separation procedures, such as radiogenic isotope ratio analyses for Sr and Nd, involve the use of multiple column separations with different resin columns, chemical reagents, and beakers of various volumes. COLUMNSPIDER completes these separations using multiple runs. Programmable functions, including the positioning of the micropipetter, reagent volume, and elution time, enable flexible operation. Optimized movements for solution take-up and high-efficiency column flushing allow the system to perform as precisely as when carried out manually by a skilled operator. Procedural blanks, examined for COLUMNSPIDER separations of Sr, Nd, and Pb, are low and negligible. The measured Sr, Nd, and Pb isotope ratios for JB-2 and Nd isotope ratios for JB-3 and BCR-2 rock standards all fall within the ranges reported previously in high-accuracy analyses. COLUMNSPIDER is a versatile tool for the efficient elemental separation of igneous rock samples, a process that is both labor intensive and time consuming.

  13. Chemical analyses and calculation of isotopic compositions of high-burnup UO{sub 2} fuels and MOX fuels

    Energy Technology Data Exchange (ETDEWEB)

    Matsumura, Tetsuo; Sasahara, Akihiro [Central Research Inst. of Electric Power Industry, Tokyo (Japan)

    2001-08-01

    Chemical analysis activities of isotopic compositions of high-burnup UO{sub 2} fuels and MOX fuels in CRIEPI and calculation evaluation are reviewed briefly. C/E values of ORIGEN2, in which original libraries and JENDL-3.2 libraries are used, and other codes with chemical analysis data are reviewed and evaluated. Isotopic compositions of main U and Pu in fuels can be evaluated within 10% relative errors by suitable libraries and codes. Void ratio is effective parameter for C/E values in BWR fuels. JENDL-3.2 library shows remarkable improvement compared with original libraries in isotopic composition evaluations of FP nuclides. (author)

  14. The use of microbial and chemical analyses to characterize the variations in fouling profile of seawater reverse osmosis (SWRO) membrane

    KAUST Repository

    Manes, Carmem Lara De O

    2013-01-01

    Biofouling of reverse osmosis (RO) membranes is one of the most common problems in desalinations plants reducing the efficiency of the water production process. The characterization of bacterial community composition from fouling layers as well as detailed analysis of surrounding chemical environment might reveal process specific bacterial groups/species that are involved in RO biofouling. In this study, advanced organics analytic methods (elemental analysis, FTIR, and ICP-OES) were combined with high-throughput 16S rRNA (pyro) sequencing to assess in parallel, the chemical properties and the active microbial community composition of SWRO membranes from a pilot desalination plant (MFT, Tarragona) in February 2011 and July 2011. Prefiltered ultrafiltration. waters fed SWRO membranes during third and fifth month of operation, respectively. SWRO samples were taken from three modules at different positions (first, fourth, and sixth) in order to investigate the spatial changes in fouling layers\\' chemical and microbiological composition. The overall assessment of chemical parameters revealed that fouling layers were mainly composed by bio and organic material (proteins and lipids). Ca and Fe were found to be the most abundant elements having an increasing concentration gradient according to the module position. Bacterial community composition of SWRO membranes is mostly represented by the Gammaproteobacteria class with interesting differences in genera/species spatial and temporal distribution. This preliminary result suggests that pretreatments and/or operational conditions might have selected different bacterial groups more adapted to colonize SWRO membranes. © 2013 Desalination Publications.

  15. How Flow Injection Analysis (FIA) over the past 25 years has changed our way of performing chemical analyses

    DEFF Research Database (Denmark)

    Hansen, Elo Harald; Miró, Manuel

    2007-01-01

    Briefly looking back on the impact of flow injection analysis (FIA), as reflected in the rapid growth of publications in the scientific literature, and touching upon many of the novel and unique analytical chemical possibilities that FIA and its sequels, sequential injection analysis (SIA) and La...

  16. Specifics of Chemical Toxilogical Analyses in the Russian Federation for the Purpose of Identification of Narcotics in Biological Matters

    Energy Technology Data Exchange (ETDEWEB)

    Coates, Cameron W [ORNL; Eisele, Gerhard R [ORNL

    2011-01-01

    The Russian Federation (RF) is committed to implementing a comprehensive drug testing program under its Personnel Reliability Program (PRP) for military personnel involved in handling sensitive nuclear materials. This commitment leads to a number of mandatory requirements for the laboratory conducting the confirmation testing to ensure the legitimacy and integrity of the testing process. These requirements are established by the RF Duma to ensure that individuals conducting these tests have adequate training, certifications, and experience to conduct narcotic confirmation tests. This paper describes the facility requirements and personnel qualifications needed for conducting comprehensive drug abuse confirmation testing. Details regarding the personnel training and laboratory experience in the theory and practice of analytical forensic toxicology of drugs of abuse will be presented, as well as the facility requirements for the laboratory conducting such tests. Chain-of-custody, from sample receipt through completion of testing, reporting of results, and continuing until final disposition of specimens will be addressed.

  17. GRANNY, a data bank of chemical analyses of Laramide and younger high-silica rhyolites and granites from Colorado and north-central New Mexico

    Science.gov (United States)

    Steigerwald, Celia H.; Mutschler, Felix E.; Ludington, Steve

    1983-01-01

    GRANNY is a data bank containing information on 507 chemically analyzed Laramide or younger high-silica rhyolites and granites from Colorado and north-central New Mexico. The data were compiled from both published and unpublished sources. The data bank is designed to aid in the recognition of igneous rocks with a high exploration potential for the discovery of molybdenum (and other lithophile element) deposits. Information on source reference, geographic location, age, mineralogic and petrologic characteristics, major constituent analyses, and trace element analyses for each sample are given. The data bank is available in two formats: 1) paper- or microfiche-hardcopy, and 2) fixed format computer readable magnetic tape.

  18. Treatment of spices with ionizing radiation - chemical, organoleptical, microbiological and toxicological analyses. Pt. 2. Behandlung von Gewuerzen mit ionisierenden Strahlen - chemische, sensorische, mikrobiologische und toxikologische Aspekte. T. 2

    Energy Technology Data Exchange (ETDEWEB)

    Schuettler, C; Boegl, W

    1984-09-01

    In the present second part of a study of the relevant literature the results of tests on 14 radiation treated spices and 2 radiation treated spice-mixtures were evaluated. The tests in this part contain mainly toxicological but also chemical and sensorial analyses. Most of the spices were treated with gamma radiation from cobalt-60 sources with doses between 80 Gy and 60 kGy. This part contains a cumulated subject index for part 1 and part 2.

  19. Operational and biological analyses of branched water-adjustment and combined treatment of wastewater from a chemical industrial park.

    Science.gov (United States)

    Xu, Ming; Cao, Jiashun; Li, Chao; Tu, Yong; Wu, Haisuo; Liu, Weijing

    2018-01-01

    The combined biological processes of branched water-adjustment, chemical precipitation, hydrolysis acidification, secondary sedimentation, Anoxic/Oxic and activated carbon treatment were used for chemical industrial wastewater treatment in the Taihu Lake Basin. Full-scale treatment resulted in effluent chemical oxygen demand, total nitrogen, NH 3 -N and total phosphorus of 35.1, 5.20, 3.10 and 0.15 mg/L, respectively, with a total removal efficiency of 91.1%, 67.1%, 70.5% and 89.3%, respectively. In this process, short-circuited organic carbon from brewery wastewater was beneficial for denitrification and second-sulfate reduction. The concentration of effluent fluoride was 6.22 mg/L, which also met the primary standard. Gas Chromatography-Mass Spectrometry analysis revealed that many types of refractory compounds were present in the inflow. Microbial community analysis performed in the summer by PCR-denaturing gradient gel electrophoresis and MiSeq demonstrated that certain special functional bacteria, such as denitrificans, phosphorus-accumulating bacteria, sulfate- and perhafnate-reducing bacteria, aromatic compound-degrading bacteria and organic fluoride-degrading bacteria, present in the bio-tanks were responsible for the acceptable specific biological pollutant reduction achieved.

  20. Chemical and magnetic analyses on tree bark as an effective tool for biomonitoring: A case study in Lisbon (Portugal).

    Science.gov (United States)

    Brignole, Daniele; Drava, Giuliana; Minganti, Vincenzo; Giordani, Paolo; Samson, Roeland; Vieira, Joana; Pinho, Pedro; Branquinho, Cristina

    2018-03-01

    Tree bark has proven to be a reliable tool for biomonitoring deposition of metals from the atmosphere. The aim of the present study was to test if bark magnetic properties can be used as a proxy of the overall metal loads of a tree bark, meaning that this approach can be used to discriminate different effects of pollution on different types of urban site. In this study, the concentrations of As, Cd, Co, Cu, Fe, Mn, Ni, P, Pb, V and Zn were measured by ICP-OES in bark samples of Jacaranda mimosifolia, collected along roads and in urban green spaces in the city of Lisbon (Portugal). Magnetic analyses were also performed on the same bark samples, measuring Isothermal Remanent Magnetization (IRM), Saturation Isothermal Remanent Magnetization (SIRM) and Magnetic Susceptibility (χ). The results confirmed that magnetic analyses can be used as a proxy of the overall load of trace elements in tree bark, and could be used to distinguish different types of urban sites regarding atmospheric pollution. Together with trace element analyses, magnetic analyses could thus be used as a tool to provide high-resolution data on urban air quality and to follow up the success of mitigation actions aiming at decreasing the pollutant load in urban environments. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. High temperature conductance mapping for correlation of electrical properties with micron-sized chemical and microstructural features

    DEFF Research Database (Denmark)

    Hansen, Karin Vels; Norrman, Kion; Jacobsen, Torben

    2016-01-01

    High temperature AC conductance mapping is a scanning probe technique for resolving local electrical properties in microscopic areas. It is especially suited for detecting poorly conducting phases and for ionically conducting materials such as those used in solid oxide electrochemical cells...

  2. Mechanical and chemical analyses across dental porcelain fused to CP titanium or Ti6Al4V

    International Nuclear Information System (INIS)

    Souza, Júlio C.M.; Henriques, Bruno; Ariza, Edith; Martinelli, Antonio E.; Nascimento, Rubens M.; Silva, Filipe S.; Rocha, Luís A.; Celis, Jean-Pierre

    2014-01-01

    The aim of this study was to evaluate the evolution of mechanical properties and chemical variation across veneering dental porcelain fused to different titanium-based substrates. Test samples were synthesized by fusing dental feldspar-based porcelain onto commercially pure titanium grade II or Ti6Al4V alloy. Samples were cross-sectioned at angles of 10 and 90° to the interface plane. Afterwards, nanoindentation tests and Scanning Electron Microscopy (SEM) imaging coupled to an Energy Dispersive Spectroscopy (EDS) system were carried out across interfaces extending from the metal towards the porcelain area. Elemental diffusion profiles across the porcelain-to-metal interfaces were also obtained by EDS analysis. The mismatch in mechanical properties found in porcelain-to-Ti6Al4V interfaces was lower than that of porcelain-to-CP titanium. Cracking was noticed at low-thickness veneering dental porcelain regions after the nanoindentation tests of samples cross-sectioned at low angles to the interface plane. A wide reaction zone between titanium and porcelain as well as higher incidence of defects was noticed at the porcelain-to-CP titanium interfaces. This study confirmed Ti6Al4V as an improved alternative to CP-titanium as it showed to establish a better interface with the veneering dental porcelain considering the slight chemical interaction and the lower mechanical properties mismatch. The elastic modulus of porcelain-to-Ti6Al4V samples showed to be less sensitive to porcelain thickness variations. - Highlights: • This study reveals mechanical and chemical behaviors across porcelain/titanium interfaces. • Cracks were noticed after nanoindentation on thin porcelain layers. • Ti6Al4V/porcelain showed a better mechanical behavior than that at CP-Ti/porcelain

  3. Changes in extra-virgin olive oil added with Lycium barbarum L. carotenoids during frying: Chemical analyses and metabolomic approach.

    Science.gov (United States)

    Blasi, F; Rocchetti, G; Montesano, D; Lucini, L; Chiodelli, G; Ghisoni, S; Baccolo, G; Simonetti, M S; Cossignani, L

    2018-03-01

    In this work, an Italian extra-virgin olive oil (EVOO) sample and the same sample added with a carotenoid-rich nutraceutical extract from Lycium barbarum L. (EVOOCar) were subjected to a frying process to comparatively assess chemical and physical changes and heat stability. Oxidation progress was monitored by measuring oil quality changes such as peroxide value, free acidity, K232, K268, and fatty acid composition as well as minor compound content, phenols, α-tocopherol, and carotenoids. An UHPLC/QTOF-MS metabolomics approach discriminated the two oil samples based on their chemical changes during frying, identifying also the phenolic classes most exposed to statistically significant variations. Partial least square discriminant analysis and volcano analysis were applied together to identify the most significant markers allowing group separation. The decrease in total phenolic content was lower in EVOOCar than in EVOO during frying. Monounsaturated and polyunsaturated fatty acids showed a significant percentage loss, 3.7% and 17.2%, respectively, in EVOO after 180min frying at 180°C, while they remained constant or slightly changed in EVOOCar. Zeaxanthin added to the oil rapidly decreased during the frying process. These findings showed that the addition of a carotenoid extract from L. barbarum can help to improve the oxidative stability of extra-virgin olive oil. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. Y-doped BaZrO3 as a chemically stable electrolyte for proton-conducting solid oxide electrolysis cells (SOECs)

    KAUST Repository

    Bi, Lei

    2015-01-01

    A proton-conducting solid oxide electrolysis cell using an Y-doped BaZrO3 electrolyte film, which has been demonstrated to be chemically stable, was successfully fabricated for the first time and showed a promising electrolysis performance.

  5. 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

  6. Candelariella placodizans (Candelariaceae reported new to mainland China and Taiwan based on morphological, chemical and molecular phylogenetic analyses

    Directory of Open Access Journals (Sweden)

    Lidia Yakovchenko

    2016-06-01

    Full Text Available Candelariella placodizans is newly reported from China. It was collected on exposed rocks with mosses on the alpine areas of Taiwan and Yunnan Province, China at elevation between 3200-4400 m. Molecular phylogenetic analyses based on ITS rDNA sequences were also performed to confirm the monophyly of the Chinese populations with respect to already existing sequences of the species, and then further to examine their relationships to other members of the genus. An identification key to all 14 known taxa of Candelariella in China is provided.

  7. The Importance of using Discounted Cash Flow Methodology in Techno-economic Analyses of Energy and Chemical Production Plants

    Directory of Open Access Journals (Sweden)

    Zorka Novak Pintarič

    2017-06-01

    Full Text Available This paper demonstrates the correct application of discounted cash flow methodology forevaluating and designing energy and chemical production plants. Such processes usuallycorrespond to capital intensive long-term projects. Simple economic criteria, like theprofit or production cost are insufficient for this type of decision making because they donot take into account the time value of money and underestimate the profitabilities of theevaluated plants. This paper shows that some of those criteria based on the discountedcash flows establish suitable compromises between long-term cash flow generation andprofitability. As several alternative options are usually evaluated in parallel, it is shownhow to rank mutually exclusive alternatives properly and how to select the best optionfrom among them. Two large-scale case studies demonstrate that using discounted cashflow methodology can result in substantially different decisions than non-discountedcriteria, however, these decisions are affected by several input parameters.

  8. Coupled Metagenomic and Chemical Analyses of Degrading Fungal Necromass and Implications for Fungal contributions to Stable Soil Organic Carbon

    Science.gov (United States)

    Egerton-Warburton, L. M.; Schreiner, K. M.; Morgan, B. S. T.; Schultz, J.; Blair, N. E.

    2016-12-01

    Fungi comprise a significant portion of total soil biomass, the turnover of which must represent a dominant flux within the soil carbon cycle. Fungal organic carbon (OC) can turn over on time scales of days to months, but this process is poorly understood. Here, we examined temporal changes in the chemical and microbial community composition of fungal necromass during a 2-month decomposition experiment in which Fusarium avenaceum (a common saprophyte) was exposed to a natural soil microbial community. Over the course of the experiment, residual fungal necromass was harvested and analyzed using FTIR and thermochemolysis-GCMS to examine chemical changes in the tissue. In addition, genomic DNA was extracted from tissues, amplified with barcoded ITS primers, and sequenced using the high-throughput Illumina platform to examine changes in microbial community composition. Up to 80% of the fungal necromass turned over in the first week. This rapid degradation phase corresponded to colonization of the necromass by known chitinolytic soil fungi including Mortierella species. Members of the Zygomycota and Ascomycota were among the dominant fungal groups involved in degradation with very small contributions from Basidiomycota. At the end of the 2-month degradation, only 15% of the original necromass remained. The residual material was rich in amide and C-O moieties which is consistent with previous work predicting that peptidoglycans are the main residual product from microbial tissue degradation. Straight-chain fatty acids exhibited varying degradation profiles, with some fatty acids (e.g. C16, C18:1) degrading more rapidly than bulk tissue while others maintained steady concentrations relative to bulk OC (C18) or increased in concentration throughout the degradation sequence (C24). These results indicate that the turnover of fungal necromass has the potential to rapidly and significantly influence a variety of soil OC properties including C/N ratios, lipid biomarker

  9. Coupled Metagenomic and Chemical Analyses of Degrading Fungal Necromass and Implications for Microbial Contributions to Stable Soil OC

    Science.gov (United States)

    Schreiner, K. M.; Morgan, B. S. T.; Schultz, J.; Blair, N. E.; Egerton-Warburton, L. M.

    2014-12-01

    Fungi comprise a significant portion of total soil biomass, the turnover of which must represent a dominant flux within the soil carbon cycle. Fungal OC can turn over on time scales of days to months, but this process is poorly understood. Here, we examined temporal changes in the chemical and microbial community composition of fungal necromass during a 2 month decomposition experiment in which Fusarium avenaceum (a common saprophyte) was exposed to a natural soil microbial community. Over the course of the experiment, residual fungal necromass was harvested and analyzed using FTIR and thermochemolysis-GCMS to examine chemical changes in the tissue. Additionally, genomic DNA was extracted from tissues, amplified with barcoded ITS primers, and sequenced using the high-throughput Illumina platform to examine changes in microbial community composition. Up to 80% of the fungal necromass turned over in the first week. This rapid degradation phase corresponded to colonization of the necromass by known chitinolytic soil fungi including Mortierella species. Zygomycetes and Ascomycetes were among the dominant fungal species involved in degradation with very small contributions from Basidiomycetes. At the end of the 2 month degradation, only 15% of the original necromass remained. The residual material was rich in amide and C-O moieties which is consistent with previous work predicting that peptidoglycans are the main residual product from microbial tissue degradation. Straight-chain fatty acids exhibit varying degradation profiles, with some fatty acids (e.g. C16 and C18:1) degrading more rapidly than bulk tissue, others maintaining steady concentrations relative to bulk OC (e.g. C18), and some increasing in concentration throughout the degradation (e.g. C24). These results indicate that the turnover of fungal necromass has the potential to significantly influence a variety of soil OC properties, including C/N ratios, lipid biomarker distributions, and OC turnover times.

  10. Ambient Monitoring for Sinclair and Dyes Inlets, Puget Sound, Washington: Chemical Analyses for 2010 Regional Mussel Watch (AMB02)

    Energy Technology Data Exchange (ETDEWEB)

    Brandenberger, Jill M. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Kuo, Li-Jung [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Suslick, Carolynn R. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Johnston, Robert K. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2010-10-20

    The Puget Sound Naval Shipyard & Intermediate Maintenance Facility (PSNS&IMF) and Naval Base Kitsap-Bremerton (Shipyard) located in Bremerton, WA are committed to a culture of continuous process improvement for all aspects of Shipyard operations, including reducing the releases of hazardous materials and waste in discharges from the Shipyard. Under the Project ENVVEST Final Project Agreement, a cooperative project among PSNS&IMF, the Environmental Protection Agency (EPA), and the Washington State Department of Ecology (Ecology), and local stakeholders (US Navy, EPA and Ecology 2002) has been helping to improve the environmental quality of the Sinclair and Dyes Inlet Watershed (ENVVEST 2006). An ambient monitoring program for sediment, water, and indigenous mussels began in 2009 to assess the status and trend of ecological resources, assess the effectiveness of cleanup and pollution control measures, and determine if discharges from all sources are protective of beneficial uses including aquatic life. This document presents the 2010 chemical residue data and stable isotopes of carbon (δ13C) and nitrogen (δ15N) for the regional mussel watch stations located in Sinclair Inlet, Dyes Inlet, Port Orchard Passage, Rich Passage, Agate Passage, Liberty Bay, and Keyport Lagoon. Indigenous bivalves were collected from a small boat and/or from along the shoreline, measured, composited, and analyzed for a suite of trace metals and organic contaminants. The trace metals included silver, arsenic, cadmium, chromium, copper, mercury, nickel, lead, and zinc. The organic contaminants included the list of NOAA Status and Trends 20 polychlorinated biphenyls (PCB) congeners and suite of parent and methylated polycyclic aromatic hydrocarbons (PAHs). These chemical residue data provide the first year of the biota ambient monitoring.

  11. Seeking excellence: An evaluation of 235 international laboratories conducting water isotope analyses by isotope-ratio and laser-absorption spectrometry.

    Science.gov (United States)

    Wassenaar, L I; Terzer-Wassmuth, S; Douence, C; Araguas-Araguas, L; Aggarwal, P K; Coplen, T B

    2018-03-15

    Water stable isotope ratios (δ 2 H and δ 18 O values) are widely used tracers in environmental studies; hence, accurate and precise assays are required for providing sound scientific information. We tested the analytical performance of 235 international laboratories conducting water isotope analyses using dual-inlet and continuous-flow isotope ratio mass spectrometers and laser spectrometers through a water isotope inter-comparison test. Eight test water samples were distributed by the IAEA to international stable isotope laboratories. These consisted of a core set of five samples spanning the common δ-range of natural waters, and three optional samples (highly depleted, enriched, and saline). The fifth core sample contained unrevealed trace methanol to assess analyst vigilance to the impact of organic contamination on water isotopic measurements made by all instrument technologies. For the core and optional samples ~73 % of laboratories gave acceptable results within 0.2 ‰ and 1.5 ‰ of the reference values for δ 18 O and δ 2 H, respectively; ~27 % produced unacceptable results. Top performance for δ 18 O values was dominated by dual-inlet IRMS laboratories; top performance for δ 2 H values was led by laser spectrometer laboratories. Continuous-flow instruments yielded comparatively intermediate results. Trace methanol contamination of water resulted in extreme outlier δ-values for laser instruments, but also affected reactor-based continuous-flow IRMS systems; however, dual-inlet IRMS δ-values were unaffected. Analysis of the laboratory results and their metadata suggested inaccurate or imprecise performance stemmed mainly from skill- and knowledge-based errors including: calculation mistakes, inappropriate or compromised laboratory calibration standards, poorly performing instrumentation, lack of vigilance to contamination, or inattention to unreasonable isotopic outcomes. To counteract common errors, we recommend that laboratories include 1-2 'known

  12. Seeking excellence: An evaluation of 235 international laboratories conducting water isotope analyses by isotope-ratio and laser-absorption spectrometry

    Science.gov (United States)

    Wassenaar, L. I.; Terzer-Wassmuth, S.; Douence, C.; Araguas-Araguas, L.; Aggarwal, P. K.; Coplen, Tyler B.

    2018-01-01

    RationaleWater stable isotope ratios (δ2H and δ18O values) are widely used tracers in environmental studies; hence, accurate and precise assays are required for providing sound scientific information. We tested the analytical performance of 235 international laboratories conducting water isotope analyses using dual-inlet and continuous-flow isotope ratio mass spectrometers and laser spectrometers through a water isotope inter-comparison test.MethodsEight test water samples were distributed by the IAEA to international stable isotope laboratories. These consisted of a core set of five samples spanning the common δ-range of natural waters, and three optional samples (highly depleted, enriched, and saline). The fifth core sample contained unrevealed trace methanol to assess analyst vigilance to the impact of organic contamination on water isotopic measurements made by all instrument technologies.ResultsFor the core and optional samples ~73 % of laboratories gave acceptable results within 0.2 ‰ and 1.5 ‰ of the reference values for δ18O and δ2H, respectively; ~27 % produced unacceptable results. Top performance for δ18O values was dominated by dual-inlet IRMS laboratories; top performance for δ2H values was led by laser spectrometer laboratories. Continuous-flow instruments yielded comparatively intermediate results. Trace methanol contamination of water resulted in extreme outlier δ-values for laser instruments, but also affected reactor-based continuous-flow IRMS systems; however, dual-inlet IRMS δ-values were unaffected.ConclusionsAnalysis of the laboratory results and their metadata suggested inaccurate or imprecise performance stemmed mainly from skill- and knowledge-based errors including: calculation mistakes, inappropriate or compromised laboratory calibration standards, poorly performing instrumentation, lack of vigilance to contamination, or inattention to unreasonable isotopic outcomes. To counteract common errors, we recommend that

  13. Assessing the ecological long-term impact of wastewater irrigation on soil and water based on bioassays and chemical analyses.

    Science.gov (United States)

    Richter, Elisabeth; Hecht, Fabian; Schnellbacher, Nadine; Ternes, Thomas A; Wick, Arne; Wode, Florian; Coors, Anja

    2015-11-01

    The reuse of treated wastewater for irrigation and groundwater recharge can counteract water scarcity and reduce pollution of surface waters, but assessing its environmental risk should likewise consider effects associated to the soil. The present study therefore aimed at determining the impact of wastewater irrigation on the habitat quality of water after soil passage and of soil after percolation by applying bioassays and chemical analysis. Lab-scale columns of four different soils encompassing standard European soil and three field soils of varying characteristics and pre-contamination were continuously percolated with treated wastewater to simulate long-term irrigation. Wastewater and its percolates were tested for immobilization of Daphnia magna and growth inhibition of green algae (Pseudokirchneriella subcapitata) and water lentils (Lemna minor). The observed phytotoxicity of the treated wastewater was mostly reduced by soil passage, but in some percolates also increased for green algae. Chemical analysis covering an extensive set of wastewater-born organic pollutants demonstrated that many of them were considerably reduced by soil passage, particularly through peaty soils. Taken together, these results indicated that wastewater-born phytotoxic substances may be removed by soil passage, while existing soil pollutants (e.g. metals) may leach and impair percolate quality. Soils with and without wastewater irrigation were tested for growth of plants (Avena sativa, Brassica napus) and soil bacteria (Arthrobacter globiformis) and reproduction of collembolans (Folsomia candida) and oligochaetes (Enchytraeus crypticus, Eisenia fetida). The habitat quality of the standard and two field soils appeared to be deteriorated by wastewater percolation for at least one organism (enchytraeids, plants or bacteria), while for two pre-contaminated field soils it also was improved (for plants and/or enchytraeids). Wastewater percolation did not seem to raise soil concentrations

  14. Ambient Monitoring for Sinclair and Dyes Inlets, Puget Sound, Washington: Chemical Analyses for 2012 Regional Mussel Watch

    Energy Technology Data Exchange (ETDEWEB)

    Brandenberger, Jill M.; Kuo, Li-Jung; Suslick, Carolynn R.; Johnston, Robert K.

    2012-09-01

    Under the Project ENVVEST Final Project Agreement, the Puget Sound Naval Shipyard & Intermediate Maintenance Facility (PSNS&IMF), Environmental Protection Agency (EPA), Washington State Department of Ecology (Ecology), and local stakeholders have worked collaboratively to improve the environmental quality of Sinclair and Dyes Inlets. A regional mussel monitoring program began in 2010 to assess the status and trend of ecological resources, assess the effectiveness of cleanup and pollution control measures, and determine if discharges from all sources are protective of beneficial uses including aquatic life. The program collected indigenous mussels to represent a time-integrated measure of bioavailable metals and organic chemicals present in the water column. This document supplements the 2010 indigenous mussel data with 2012 data to provide two years of data on the chemical residue of mussels present in the inter-tidal regions of Sinclair Inlet, Dyes Inlet, Port Orchard Passage, Rich Passage, Agate Passage, Liberty Bay, and Keyport Lagoon. The 2012 data set added one station at PSNS&IMF and one market samples from Penn Cove. Indigenous mussels were collected from a small boat and/or from along the shoreline, measured, composited, and analyzed for percent lipids, percent moisture, stable isotopes of carbon and nitrogen, and a suite of trace metals and organic contaminants. The trace metals included silver (Ag), arsenic (As), cadmium (Cd), copper (Cu), mercury (Hg), lead (Pb), and zinc (Zn). The organic contaminants included the list of NOAA Status and Trends 20 polychlorinated biphenyls (PCB) congeners and suite of parent and methylated polycyclic aromatic hydrocarbons (PAHs). The average lengths between the 2010 and 2012 data were generally less than 30% relative percent difference (RPD). Generally, the metals concentrations were lower in 2012 than 2010 with some notable exceptions in Sinclair Inlet and Rich Passage where increases in Ag, Hg, Pb, Cu, and Zn exceeded

  15. Evaluation of chemical changes during Myrciaria cauliflora (jabuticaba fruit) fermentation by {sup 1}H NMR spectroscopy and chemometric analyses

    Energy Technology Data Exchange (ETDEWEB)

    Fortes, Gilmara A.C.; Naves, Sara S.; Ferri, Pedro H.; Santos, Suzana C., E-mail: suzana.quimica.ufg@hotmail.com [Universidade Federal de Goias (UFG), Goiania, GO (Brazil). Inst. de Quimica. Lab. de Bioatividade Molecular

    2012-10-15

    Organic acids, sugars, alcohols, phenolic compounds, color properties, pH and titratable acidity were monitored during the commercial fermentation of jabuticaba (Myrciaria cauliflora) by {sup 1}H nuclear magnetic resonance (NMR) spectroscopy, spectrophotometric assays and standard methods of analysis. Data collected was analyzed by principal component (PCA), hierarchical cluster (HCA) and canonical correlation (CCA) analyses. Two sample groups were distinguished and the variables responsible for separation were sugars, anthocyanins, alcohols, hue and acetic and succinic acids. The canonical correlation analysis confirmed the influence of alcohols (ethanol, methanol and glycerol), organic acids (citric, succinic and acetic acids), pH and titratable acidity on the extraction and stability of anthocyanins and co pigments. As a result, color properties were also affected by phenolic variation throughout the fermentative process. (author)

  16. An easily sintered, chemically stable, barium zirconate-based proton conductor for high-performance proton-conducting solid oxide fuel cells

    KAUST Repository

    Sun, Wenping

    2014-07-25

    Yttrium and indium co-doped barium zirconate is investigated to develop a chemically stable and sintering active proton conductor for solid oxide fuel cells (SOFCs). BaZr0.8Y0.2-xInxO3- δ possesses a pure cubic perovskite structure. The sintering activity of BaZr0.8Y0.2-xInxO3- δ increases significantly with In concentration. BaZr0.8Y0.15In0.05O3- δ (BZYI5) exhibits the highest total electrical conductivity among the sintered oxides. BZYI5 also retains high chemical stability against CO2, vapor, and reduction of H2. The good sintering activity, high conductivity, and chemical stability of BZYI5 facilitate the fabrication of durable SOFCs based on a highly conductive BZYI5 electrolyte film by cost-effective ceramic processes. Fully dense BZYI5 electrolyte film is successfully prepared on the anode substrate by a facile drop-coating technique followed by co-firing at 1400 °C for 5 h in air. The BZYI5 film exhibits one of the highest conductivity among the BaZrO3-based electrolyte films with various sintering aids. BZYI5-based single cells output very encouraging and by far the highest peak power density for BaZrO3-based proton-conducting SOFCs, reaching as high as 379 mW cm-2 at 700 °C. The results demonstrate that Y and In co-doping is an effective strategy for exploring sintering active and chemically stable BaZrO3-based proton conductors for high performance proton-conducting SOFCs. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Characterization of microbial and chemical composition of shuttle wet waste with permanent gas and volatile organic compound analyses

    Science.gov (United States)

    Peterson, B. V.; Hummerick, M.; Roberts, M. S.; Krumins, V.; Kish, A. L.; Garland, J. L.; Maxwell, S.; Mills, A.

    2004-01-01

    Solid-waste treatment in space for Advanced Life Support, ALS, applications requires that the material can be safely processed and stored in a confined environment. Many solid-wastes are not stable because they are wet (40-90% moisture) and contain levels of soluble organic compounds that can contribute to the growth of undesirable microorganisms with concomitant production of noxious odors. In the absence of integrated Advanced Life Support systems on orbit, permanent gas, trace volatile organic and microbiological analyses were performed on crew refuse returned from the volume F "wet" trash of three consecutive Shuttle missions (STS-105, 109, and 110). These analyses were designed to characterize the short-term biological stability of the material and assess potential crew risks resulting from microbial decay processes during storage. Waste samples were collected post-orbiter landing and sorted into packaging material, food waste, toilet waste, and bulk liquid fractions deposited during flight in the volume F container. Aerobic and anaerobic microbial loads were determined in each fraction by cultivation on R2A and by acridine orange direct count (AODC). Dry and ash weights were performed to determine both water and organic content of the materials. Experiments to determine the aerobic and anaerobic biostability of refuse stored for varying periods of time were performed by on-line monitoring of CO2 and laboratory analysis for production of hydrogen sulfide and methane. Volatile organic compounds and permanent gases were analyzed using EPA Method TO15 by USEPA et al. [EPA Method TO15, The Determination of Volatile Organic Compounds (VOCs) in Ambient Air using SUMMA, Passivated Canister Sampling and Gas Chromatographic Analysis,1999] with gas chromatography/mass spectrometry and by gas chromatography with selective detectors. These baseline measures of waste stream content, labile organics, and microbial load in the volume F Shuttle trash provide data for waste

  18. Chemical Differentiation of Dendrobium officinale and Dendrobium devonianum by Using HPLC Fingerprints, HPLC-ESI-MS, and HPTLC Analyses

    Science.gov (United States)

    Ye, Zi; Dai, Jia-Rong; Zhang, Cheng-Gang; Lu, Ye; Wu, Lei-Lei; Gong, Amy G. W.; Wang, Zheng-Tao

    2017-01-01

    The stems of Dendrobium officinale Kimura et Migo (Dendrobii Officinalis Caulis) have a high medicinal value as a traditional Chinese medicine (TCM). Because of the limited supply, D. officinale is a high priced TCM, and therefore adulterants are commonly found in the herbal market. The dried stems of a closely related Dendrobium species, Dendrobium devonianum Paxt., are commonly used as the substitute; however, there is no effective method to distinguish the two Dendrobium species. Here, a high performance liquid chromatography (HPLC) method was successfully developed and applied to differentiate D. officinale and D. devonianum by comparing the chromatograms according to the characteristic peaks. A HPLC coupled with electrospray ionization multistage mass spectrometry (HPLC-ESI-MS) method was further applied for structural elucidation of 15 flavonoids, 5 phenolic acids, and 1 lignan in D. officinale. Among these flavonoids, 4 flavonoid C-glycosides were firstly reported in D. officinale, and violanthin and isoviolanthin were identified to be specific for D. officinale compared with D. devonianum. Then, two representative components were used as chemical markers. A rapid and reliable high performance thin layer chromatography (HPTLC) method was applied in distinguishing D. officinale from D. devonianum. The results of this work have demonstrated that these developed analytical methods can be used to discriminate D. officinale and D. devonianum effectively and conveniently. PMID:28769988

  19. Chemical analyses and in vitro and in vivo toxicity of fruit methanol extract of Sechium edule var. nigrum spinosum.

    Science.gov (United States)

    Aguiñiga-Sánchez, Itzen; Cadena-Íñiguez, Jorge; Santiago-Osorio, Edelmiro; Gómez-García, Guadalupe; Mendoza-Núñez, Víctor Manuel; Rosado-Pérez, Juana; Ruíz-Ramos, Mirna; Cisneros-Solano, Víctor Manuel; Ledesma-Martínez, Edgar; Delgado-Bordonave, Angel de Jesus; Soto-Hernández, Ramón Marcos

    2017-12-01

    Sechium edule (Jacq.) Sw. (Cucurbitaceae) is used in ethnomedicine, but the diversity of the varietal groups of this species has not often been considered. This is important because we previously reported that different variety of species exhibit different activities across different tumor cell lines. This study investigates the chemical composition and biological activities of extracts obtained from S. edule var. nigrum spinosum. The leukemia P388 cell line and mononuclear bone marrow cells (MNCBMs) were treated with the extract at a concentration ranging from 40 to 2370 μg/mL for cytotoxicity and viability assays. CD-1 mice were treated with 8-5000 mg/kg extract and monitored every hour for the first 24 h and subsequently for seven days for signs of toxicity (LD 50 ). In addition, the chromatographic profile of the extract was determined by HPLC. The extract inhibits the proliferation of both P388 cells and MNCBMs, with IC 50 values of 927 and 1911 μg/mL, respectively, but reduced the viability and induced the apoptosis of only leukemia cells. The LD 50 was higher than 5000 mg/kg, and this concentration did not alter the blood chemistry or cell count but doubled the mitotic index in the bone marrow. The HPLC showed the presence of cucurbitacins, phloridzin, naringenin, phloretin, apigenin, and gallic, chlorogenic, vanillic, p-hydroxybenzoic, caffeic, and p-coumaric acids. Sechium edule var. nigrum spinosum contains bioactive compounds that explain the antiproliferative and nutraceutical activities, and its lack of physiological side effects constitutes an added value to a widely consumed vegetable.

  20. Chemical analyses of hot springs, pools, geysers, and surface waters from Yellowstone National Park, Wyoming, and vicinity, 1974-1975

    Science.gov (United States)

    Ball, James W.; Nordstrom, D. Kirk; Jenne, Everett A.; Vivit, Davison V.

    1998-01-01

    This report presents all analytical determinations for samples collected from Yellowstone National Park and vicinity during 1974 and 1975. Water temperature, pH, Eh, and dissolved O2 were determined on-site. Total alkalinity and F were determined on the day of sample collection. Flame atomic-absorption spectrometry was used to determine concentrations of Li, Na, K, Ca, and Mg. Ultraviolet/visible spectrophotometry was used to determine concentrations of Fe(II), Fe(III), As(III), and As(V). Direct-current plasma-optical-emission spectrometry was used to determine the concentrations of B, Ba, Cd, Cs, Cu, Mn, Ni, Pb, Rb, Sr, and Zn. Two samples collected from Yellowstone Park in June 1974 were used as reference samples for testing the plasma analytical method. Results of these tests demonstrate acceptable precision for all detectable elements. Charge imbalance calculations revealed a small number of samples that may have been subject to measurement errors in pH or alkalinity. These data represent some of the most complete analyses of Yellowstone waters available.

  1. Chemical and physical properties of the normal and aging lens: spectroscopic (UV, fluorescence, phosphorescence, and NMR) analyses

    International Nuclear Information System (INIS)

    Lerman, S.

    1987-01-01

    In vitro [UV absorption, fluorescence, phosphorescence, and nuclear magnetic resonance (NMR)] spectroscopic studies on the normal human lens demonstrate age-related changes which can be correlated with biochemical and photobiologic mechanisms occurring during our lifetime. Chronic cumulative UV exposure results in an age-related increase of photochemically induced chromophores and in color of the lens nucleus. This enables the lens to filter the incident UV radiation, thereby protecting the underlying aging retina from UV photodamage. We have measured the age-related increase in lens fluorescence in vivo on more than 300 normal subjects (1st to 9th decade) by UV slitlamp densitography. These data show a good correlation with the in vitro lens fluorescence studies reported previously and demonstrate that molecular photodamage can be monitored in the lens. In vitro NMR (human and animal lenses) and in vivo experiments currently in progress are rapidly elucidating the physicochemical basis for transparency and the development of light scattering areas. Surface scanning NMR can monitor organophosphate metabolism in the ocular lens in vivo as well as in vitro. These studies demonstrate the feasibility of using biophysical methods (optical spectroscopy and NMR analyses) to delineate age-related parameters in the lens, in vivo as well as in vitro. 46 references

  2. Electrical conductivity and chemical stability of BaCe0·8−xAxGd0 ...

    Indian Academy of Sciences (India)

    −1 in air at 1073 K. BaCe0·7In0·1Gd0·2O3−δ and BaCe0·7Zr0·1Gd0·2O3−δ ceramics exhibit an ... cells convert chemical energy directly into electrical energy and their ... peratures in the presence of CO2 and water vapour (Haile. 2003 ...

  3. Comparative physical-chemical characterization of encapsulated lipid-based isotretinoin products assessed by particle size distribution and thermal behavior analyses

    Energy Technology Data Exchange (ETDEWEB)

    Guimaraes, Carla Aiolfi, E-mail: carlaaiolfi@usp.br [Department of Pharmacy, Faculty of Pharmaceutical Sciences, University of Sao Paulo, Sao Paulo, SP 05508-000 (Brazil); Menaa, Farid [Department of Dermatology, School of Medicine Wuerzburg, Wuerzburg 97080 (Germany); Fluorotronics, Inc., 1425 Russ Bvld, San Diego Technology Incubator, San Diego, CA 92101 (United States); Menaa, Bouzid, E-mail: bouzid.menaa@gmail.com [Fluorotronics, Inc., 1425 Russ Bvld, San Diego Technology Incubator, San Diego, CA 92101 (United States); Quenca-Guillen, Joyce S. [Department of Pharmacy, Faculty of Pharmaceutical Sciences, University of Sao Paulo, Sao Paulo, SP 05508-000 (Brazil); Matos, Jivaldo do Rosario [Department of Fundamental Chemistry, Institute of Chemistry, University of Sao Paulo, Sao Paulo, SP 05508-000 (Brazil); Mercuri, Lucildes Pita [Department of Exact and Earth Sciences, Federal University of Sao Paulo, Diadema, SP 09972-270 (Brazil); Braz, Andre Borges [Department of Engineering of Mines and Oil, Polytechnical School, University of Sao Paulo, SP 05508-900 (Brazil); Rossetti, Fabia Cristina [Department of Pharmaceutical Sciences, Faculty of Pharmaceutical Sciences of Ribeirao Preto, University of Sao Paulo, Ribeirao Preto, SP 14015-120 (Brazil); Kedor-Hackmann, Erika Rosa Maria; Santoro, Maria Ines Rocha Miritello [Department of Pharmacy, Faculty of Pharmaceutical Sciences, University of Sao Paulo, Sao Paulo, SP 05508-000 (Brazil)

    2010-06-10

    Isotretinoin is the drug of choice for the management of severe recalcitrant nodular acne. Nevertheless, some of its physical-chemical properties are still poorly known. Hence, the aim of our study consisted to comparatively evaluate the particle size distribution (PSD) and characterize the thermal behavior of the three encapsulated isotretinoin products in oil suspension (one reference and two generics) commercialized in Brazil. Here, we show that the PSD, estimated by laser diffraction and by polarized light microscopy, differed between the generics and the reference product. However, the thermal behavior of the three products, determined by thermogravimetry (TGA), differential thermal (DTA) analyses and differential scanning calorimetry (DSC), displayed no significant changes and were more thermostable than the isotretinoin standard used as internal control. Thus, our study suggests that PSD analyses in isotretinoin lipid-based formulations should be routinely performed in order to improve their quality and bioavailability.

  4. Anti-oxidant activity and major chemical component analyses of twenty-six commercially available essential oils

    Directory of Open Access Journals (Sweden)

    Hsiao-Fen Wang

    2017-10-01

    Full Text Available This study analyzed 26 commercially available essential oils and their major chemical components to determine their antioxidant activity levels by measuring their total phenolic content (TPC, reducing power (RP, β-carotene bleaching (BCB activity, trolox equivalent antioxidant capacity (TEAC, and 1,1-diphenyl-2-picrylhydrazyl free radical scavenging (DFRS ability. The clove bud and thyme borneol essential oils had the highest RP, BCB activity levels, and TPC values among the 26 commercial essential oils. Furthermore, of the 26 essential oils, the clove bud and ylang ylang complete essential oils had the highest TEAC values, and the clove bud and jasmine absolute essential oils had the highest DFRS ability. At a concentration of 2.5 mg/mL, the clove bud and thyme borneol essential oils had RP and BCB activity levels of 94.56% ± 0.06% and 24.64% ± 0.03% and 94.58% ± 0.01% and 89.33% ± 0.09%, respectively. At a concentration of 1 mg/mL, the clove bud and thyme borneol essential oils showed TPC values of 220.00 ± 0.01 and 69.05 ± 0.01 mg/g relative to gallic acid equivalents, respectively, and the clove bud and ylang ylang complete essential oils had TEAC values of 809.00 ± 0.01 and 432.33 ± 0.01 μM, respectively. The clove bud and jasmine absolute essential oils showed DFRS abilities of 94.13% ± 0.01% and 78.62% ± 0.01%, respectively. Phenolic compounds of the clove bud, thyme borneol and jasmine absolute essential oils were eugenol (76.08%, thymol (14.36% and carvacrol (12.33%, and eugenol (0.87%, respectively. The phenolic compounds in essential oils were positively correlated with the RP, BCB activity, TPC, TEAC, and DFRS ability.

  5. Anti-oxidant activity and major chemical component analyses of twenty-six commercially available essential oils.

    Science.gov (United States)

    Wang, Hsiao-Fen; Yih, Kuang-Hway; Yang, Chao-Hsun; Huang, Keh-Feng

    2017-10-01

    This study analyzed 26 commercially available essential oils and their major chemical components to determine their antioxidant activity levels by measuring their total phenolic content (TPC), reducing power (RP), β-carotene bleaching (BCB) activity, trolox equivalent antioxidant capacity (TEAC), and 1,1-diphenyl-2-picrylhydrazyl free radical scavenging (DFRS) ability. The clove bud and thyme borneol essential oils had the highest RP, BCB activity levels, and TPC values among the 26 commercial essential oils. Furthermore, of the 26 essential oils, the clove bud and ylang ylang complete essential oils had the highest TEAC values, and the clove bud and jasmine absolute essential oils had the highest DFRS ability. At a concentration of 2.5 mg/mL, the clove bud and thyme borneol essential oils had RP and BCB activity levels of 94.56% ± 0.06% and 24.64% ± 0.03% and 94.58% ± 0.01% and 89.33% ± 0.09%, respectively. At a concentration of 1 mg/mL, the clove bud and thyme borneol essential oils showed TPC values of 220.00 ± 0.01 and 69.05 ± 0.01 mg/g relative to gallic acid equivalents, respectively, and the clove bud and ylang ylang complete essential oils had TEAC values of 809.00 ± 0.01 and 432.33 ± 0.01 μM, respectively. The clove bud and jasmine absolute essential oils showed DFRS abilities of 94.13% ± 0.01% and 78.62% ± 0.01%, respectively. Phenolic compounds of the clove bud, thyme borneol and jasmine absolute essential oils were eugenol (76.08%), thymol (14.36%) and carvacrol (12.33%), and eugenol (0.87%), respectively. The phenolic compounds in essential oils were positively correlated with the RP, BCB activity, TPC, TEAC, and DFRS ability. Copyright © 2017. Published by Elsevier B.V.

  6. Phytotoxicology surveys conducted in the Town of Elmira: Uniroyal Corporation, 1989, Sulco Canada Colours Ltd. , 1990, Varnicolor Chemical Ltd. , 1990. Report No. ARB-027-92-PHYTO

    Energy Technology Data Exchange (ETDEWEB)

    McIlveen, W D

    1993-01-01

    The Town of Elmira is a centre for several small chemical industries. With the discovery of NDMA in the Town of Elmira's water supplies in November 1989, residents became concerned about possible contamination of soil and vegetation from air and surface-water transport from the other chemical industries in the town. This report is a compilation of the data obtained from the investigations conducted in the vicinity of the Uniroyal Corp., Sulco Canada Ltd., and Varnicolor Chemical Ltd. Sample sites were selected around each of the sources based on scale of operation, nature of the probable contaminants, availability of vegetation which still had attached foliage at the time of the initial visit, and at various distances and directions including the residential parts of the town.

  7. Effects of chemical synthesis parameters on the Zr O2: 8% mol Mg O solid electrolytes electric conductivity and microstructure

    International Nuclear Information System (INIS)

    Avila, D.M.; Muccillo, E.N.S.

    1996-01-01

    Electrical conductivity measurements and scanning electron microscope observations have been done in Zr O 2 - 8 mol % Mg O solid electrolytes. The main purpose was to investigate to what extent some processing variables can influence the electrical behaviour and microstructural characteristics of the sintered ceramic. Zirconia powders have been prepared under different pH and temperature of precipitation, and washing media conditions. The results show that many structural characteristics of the calcined powders are 'lost' during sintering, giving rise to ceramics with similar electrical properties, besides minor differences in the final microstructure. The washing media play the major role on both microstructural development and electrical conductivity. (author)

  8. In-plane conductance of thin films as a probe of surface chemical environment: Adsorbate effects on film electronic properties of indium tin oxide and gold

    Science.gov (United States)

    Swint, Amy Lynn

    Changes in the in-plane conductance of conductive thin films are observed as a result of chemical adsorption at the surface. Reaction of the indium tin oxide (ITO) surface with Bronsted acids (bases) leads to increases (decreases) in its in-plane conductance as measured by a four-point probe configuration. The conductance varies monotonically with pH suggesting that the degree of surface protonation or hydroxylation controls the surface charge density, which in turn affects the width of the n-type depletion layer, and ultimately the in-plane conductance. Measurements at constant pH with a series of tetraalkylammonium hydroxide species of varying cation size indicate that surface dipoles also affect ITO conductance by modulating the magnitude of the surface polarization. Modulating the double layer with varying aqueous salt solutions also affects ITO conductance, though not to the same degree as strong Bronsted acids and bases. Solvents of varying dielectric constant and proton donating ability (ethanol, dimethylformamide) decrease ITO conductance relative to H2O. In addition, changing solvent gives rise to thermally-derived conductance transients, which result from exothermic solvent mixing. The self-assembly of alkanethiols at the surface increases the conductance of ITO films, most likely through carrier population effects. In all cases examined the combined effects of surface charge, adsorbed dipole layer magnitude and carrier injection are responsible for altering the ITO conductance. Besides being directly applicable to the control of electronic properties, these results also point to the use of four-point probe resistance measurements in condensed phase sensing applications. Ultrasensitive conductance-based gas phase sensing of organothiol adsorption to gold nanowires is accomplished with a limit of detection in the 105 molecule range. Further refinement of the inherently low noise resistance measurement may lead to observation of single adsorption events at

  9. Steam Electrolysis by Proton-Conducting Solid Oxide Electrolysis Cells (SOECs) with Chemically Stable BaZrO3-Based Electrolytes

    KAUST Repository

    Bi, Lei

    2015-07-17

    BaZrO3-based material was applied as the electrolyte for proton-conducting solid oxide fuel cells (SOECs). Compared with the instability of BaCeO3-based proton-conductors, BaZrO3-based material could be a more promising candidate for proton-conducting SOECs due to its excellent chemical stability under H2O conditions, but few reports on this aspect has been made due to the processing difficulty for BaZrO3. Our recent pioneering work has demonstrated the feasibility of using BaZrO3-based electrolyte for SOECs and the fabricated cell achieves relatively high cell performance, which is comparable or even higher than that for BaCeO3-based SOECs and offers better chemical stability. Cell performance can be further improved by tailoring the electrolyte and electrode. © The Electrochemical Society.

  10. Biomonitoring in a clean and a multi-contaminated estuary based on biomarkers and chemical analyses in the endobenthic worm Nereis diversicolor

    Energy Technology Data Exchange (ETDEWEB)

    Durou, Cyril [CNRS, Universite de Nantes, Pole Mer et Littoral, SMAB, 2 rue de la Houssiniere, BP 92208, F-44322 Nantes Cedex 3 (France) and Institut de Biologie et Ecologie Appliquees, CEREA, Universite Catholique de l' Ouest, 44 rue Rabelais, 49008 Angers Cedex 01 (France)]. E-mail: cyril.durou@uco.fr; Poirier, Laurence [CNRS, Universite de Nantes, Pole Mer et Littoral, SMAB, 2 rue de la Houssiniere, BP 92208, F-44322 Nantes Cedex 3 (France); Amiard, Jean-Claude [CNRS, Universite de Nantes, Pole Mer et Littoral, SMAB, 2 rue de la Houssiniere, BP 92208, F-44322 Nantes Cedex 3 (France); Budzinski, Helene [CNRS UMR 5472, LPTC, Universite de Bordeaux I, 33405 Talence (France); Gnassia-Barelli, Mauricette [UMR INRA UNSA 1112 ROSE, Faculte des Sciences, BP 71, 06108 Nice Cedex 2 (France); Lemenach, Karyn [CNRS UMR 5472, LPTC, Universite de Bordeaux I, 33405 Talence (France); Peluhet, Laurent [CNRS UMR 5472, LPTC, Universite de Bordeaux I, 33405 Talence (France); Mouneyrac, Catherine [CNRS, Universite de Nantes, Pole Mer et Littoral, SMAB, 2 rue de la Houssiniere, BP 92208, F-44322 Nantes Cedex 3 (France); Institut de Biologie et Ecologie Appliquees, CEREA, Universite Catholique de l' Ouest, 44 rue Rabelais, 49008 Angers Cedex 01 (France); Romeo, Michele [UMR INRA UNSA 1112 ROSE, Faculte des Sciences, BP 71, 06108 Nice Cedex 2 (France); Amiard-Triquet, Claude [CNRS, Universite de Nantes, Pole Mer et Littoral, SMAB, 2 rue de la Houssiniere, BP 92208, F-44322 Nantes Cedex 3 (France)

    2007-07-15

    Relationships between biochemical and physiological biomarkers (acetylcholinesterase [AChE], catalase, and glutathione S-transferase [GST] activities, thiobarbituric acid reactive substances, glycogen, lipids and proteins) and accumulated concentrations of contaminants (polychlorinated biphenyls [PCBs], polycyclic aromatic hydrocarbons and metals) were examined in the keystone species Nereis diversicolor. The chemical analyses of worms and sediments allowed the designation of the Seine estuary and the Authie estuary as a polluted and relatively clean site respectively. Worms from the Seine estuary exhibited higher GST and lower AChE activities. Generally, larger worms had higher concentrations of energy reserves. Principal component analyses clearly highlighted intersite differences: in the first plan, GST activities and chemical concentrations were inversely related to concentrations of energy reserves; in the second one, PCB concentrations and AChE activity were inversely related. Depleted levels of energy reserves could be a consequence of combating toxicants and might predict effects at higher levels of biological organization. The use of GST and AChE activities and energy reserve concentrations as biomarkers is validated in the field in this keystone species. - The use of N. diversicolor as a biomonitor of environmental quality via the measurement of biomarkers and accumulated concentrations of contaminants is validated in the field.

  11. Ethics and the Responsible Conduct of Research in the Chemical Community: The Unique Role and Challenges of the News Media.

    Science.gov (United States)

    Schulz, William G

    2015-01-01

    Journalists who cover scientific research, including chemistry research, have an obligation to report on alleged cases of research misconduct when knowledge of these surface. New Government definitions of research misconduct, beginning in the late 1990s with the Clinton Administration, have helped scientists, policymakers, as well as journalists sort out and make sense of alleged research misconduct. Journalistic reporting on research misconduct includes many challenges: gathering information from sources who are intimidated or afraid to speak, strict adherence to journalist ethics that take on a new dimension when careers, reputations, and research funding are at stake; efforts by government and institutional bureaucrats to dampen or thwart legitimate news coverage. The Internet, blogging, and social media have added still more complexity and ethical quandaries to this blend. The author, News Editor of Chemical & Engineering News published by the American Chemical Society, provides examples from his own career and that of colleagues. He suggests that an enhanced spirit of understanding and cooperation between journalists and members of the scientific community can lead to avenues of open discussion of research misconduct--discussions that might prevent and mitigate the very real damage caused by bad actors in science who betray themselves, their peers, and the body of modern day scientific knowledge when they make the decision to march into the darkness of dishonesty, plagiarism, or falsification.

  12. Vascugraft polyurethane arterial prosthesis as femoro-popliteal and femoro-peroneal bypasses in humans: pathological, structural and chemical analyses of four excised grafts.

    Science.gov (United States)

    Zhang, Z; Marois, Y; Guidoin, R G; Bull, P; Marois, M; How, T; Laroche, G; King, M W

    1997-01-01

    Following positive results obtained in in vitro studies and in vivo implantations in animals, a clinical trial using the Vascugraft polyurethane arterial prosthesis as a below-knee substitute was undertaken in 15 patients. Eight grafts became occluded during the first year, and segments from four of them were explanted and made available for pathological, structural and chemical investigations. The implantation periods ranged from 21 to 358 days. Failures were associated with kinking (one case), possible anastomotic mismatch between the graft and the artery (one case), and poor run-off (two cases). No organized collagenous internal encapsulation was noted; however, endothelial-like cells were observed at the anastomotic site of one graft. No significant structural degradation of the prostheses was observed in those grafts implanted for 21, 38 and 46 days. Some deteriorations in the fibrous structure were observed on the external surface of the prosthesis implanted for 358 days. High-resolution carbon C1s analysis by ESCA demonstrated a 60 to 80% decrease in carbonate content on the surface of all explanted prostheses. Chemical analyses of each polyurethane graft by IR, SEC and DSC revealed no significant chemical changes. The clinical performance of the Vascugraft prosthesis for below-knee implantation proved to be no more impressive than that of expanded polytetrafluorethylene, the currently accepted reference. The decision by B. Braun Melsungen AG to end this program is therefore to be regarded as highly professional.

  13. Paraffin/expanded graphite phase change composites with enhanced thermal conductivity prepared by implanted β-SiC nanowires with chemical vapor deposition method

    Science.gov (United States)

    Yin, Zhaoyu; Zhang, Xiaoguang; Huang, Zhaohui; Liu, Silin; Zhang, Weiyi; Liu, Yan'gai; Wu, Xiaowen; Fang, Minghao; Min, Xin

    2018-02-01

    Expanded graphite/β-SiC nanowires composites (ESNC) were prepared through chemical vapor deposition, and paraffin/expanded graphite/β-SiC nanowires composites (PESNC) were made through vacuum impregnation to overcome liquid leakage during phase transition and enhance the thermal conductivity of paraffin. Fourier transform infrared spectroscopy showed no chemical interactions between the paraffin and ESNC. Differential scanning calorimetry estimated the temperature and latent heat of PESNC during melting to 45.73 °C and 124.31 J g-1, respectively. The respective values of these quantities during freezing were recorded as 48.93 °C and 124.14 J g-1. The thermal conductivity of PESNC was estimated to 0.75 W mK-1, which was 3.26-folds that of pure paraffin (0.23 W mK-1). PESNC perfectly maintained its phase transition after 200 melting-freezing cycles. The resulting ideal thermal conductivity, good chemical stability, thermal properties and thermal reliability of PESNC are promising for use in energy efficient buildings and solar energy systems.

  14. Dynamics and spike trains statistics in conductance-based integrate-and-fire neural networks with chemical and electric synapses

    International Nuclear Information System (INIS)

    Cofré, Rodrigo; Cessac, Bruno

    2013-01-01

    We investigate the effect of electric synapses (gap junctions) on collective neuronal dynamics and spike statistics in a conductance-based integrate-and-fire neural network, driven by Brownian noise, where conductances depend upon spike history. We compute explicitly the time evolution operator and show that, given the spike-history of the network and the membrane potentials at a given time, the further dynamical evolution can be written in a closed form. We show that spike train statistics is described by a Gibbs distribution whose potential can be approximated with an explicit formula, when the noise is weak. This potential form encompasses existing models for spike trains statistics analysis such as maximum entropy models or generalized linear models (GLM). We also discuss the different types of correlations: those induced by a shared stimulus and those induced by neurons interactions

  15. Taxometric analyses and predictive accuracy of callous-unemotional traits regarding quality of life and behavior problems in non-conduct disorder diagnoses

    NARCIS (Netherlands)

    Herpers, P.C.M.; Klip, H.; Rommelse, N.N.J.; Taylor, M.J.; Greven, C.U.; Buitelaar, J.K.

    2017-01-01

    Callous-unemotional (CU) traits have mainly been studied in relation to conduct disorder (CD), but can also occur in other disorder groups. However, it is unclear whether there is a clinically relevant cut-off value of levels of CU traits in predicting reduced quality of life (QoL) and clinical

  16. A Tri-Layer Proton-Conducting Electrolyte for Chemically Stable Operation in Solid Oxide Fuel Cells

    KAUST Repository

    Bi, Lei; Traversa, Enrico

    2013-01-01

    Two BaZr0.7Pr0.1Y0.2O3-δ (BZPY) layers were used to sandwich a BaCe0.8Y0.2O3-δ (BCY) layer to produce a tri-layer electrolyte consisting of BZPY/BCY/BZPY. The BZPY layers significantly improved the chemical stability of the BCY electrolyte layer, which was not stable when tested alone, suggesting that the BZPY layer effectively protected the BCY layer from CO2 reaction, which is the major problem of BCY-based materials. A fuel cell with this sandwiched electrolyte supported on a Ni-based composite anode showed a reasonable cell performance, reaching 185 mW cm-2 at 700 oC, in spite of the relatively large electrolyte thickness (about 65 µm).

  17. A Tri-Layer Proton-Conducting Electrolyte for Chemically Stable Operation in Solid Oxide Fuel Cells

    KAUST Repository

    Bi, Lei

    2013-10-07

    Two BaZr0.7Pr0.1Y0.2O3-δ (BZPY) layers were used to sandwich a BaCe0.8Y0.2O3-δ (BCY) layer to produce a tri-layer electrolyte consisting of BZPY/BCY/BZPY. The BZPY layers significantly improved the chemical stability of the BCY electrolyte layer, which was not stable when tested alone, suggesting that the BZPY layer effectively protected the BCY layer from CO2 reaction, which is the major problem of BCY-based materials. A fuel cell with this sandwiched electrolyte supported on a Ni-based composite anode showed a reasonable cell performance, reaching 185 mW cm-2 at 700 oC, in spite of the relatively large electrolyte thickness (about 65 µm).

  18. Steady- and transient-state analyses of fully ceramic microencapsulated fuel loaded reactor core via two-temperature homogenized thermal-conductivity model

    International Nuclear Information System (INIS)

    Lee, Yoonhee; Cho, Nam Zin

    2015-01-01

    Highlights: • Fully ceramic microencapsulated fuel-loaded core is analyzed via a two-temperature homogenized thermal-conductivity model. • The model is compared to harmonic- and volumetric-average thermal conductivity models. • The three thermal analysis models show ∼100 pcm differences in the k eff eigenvalue. • The three thermal analysis models show more than 70 K differences in the maximum temperature. • There occur more than 3 times differences in the maximum power for a control rod ejection accident. - Abstract: Fully ceramic microencapsulated (FCM) fuel, a type of accident-tolerant fuel (ATF), consists of TRISO particles randomly dispersed in a SiC matrix. In this study, for a thermal analysis of the FCM fuel with such a high heterogeneity, a two-temperature homogenized thermal-conductivity model was applied by the authors. This model provides separate temperatures for the fuel-kernels and the SiC matrix. It also provides more realistic temperature profiles than those of harmonic- and volumetric-average thermal conductivity models, which are used for thermal analysis of a fuel element in VHTRs having a composition similar to the FCM fuel, because such models are unable to provide the fuel-kernel and graphite matrix temperatures separately. In this study, coupled with a neutron diffusion model, a FCM fuel-loaded reactor core is analyzed via a two-temperature homogenized thermal-conductivity model at steady- and transient-states. The results are compared to those from harmonic- and volumetric-average thermal conductivity models, i.e., we compare k eff eigenvalues, power distributions, and temperature profiles in the hottest single-channel at steady-state. At transient-state, we compare total powers, reactivity, and maximum temperatures in the hottest single-channel obtained by the different thermal analysis models. The different thermal analysis models and the availability of fuel-kernel temperatures in the two-temperature homogenized thermal-conductivity

  19. Assessment of wastewater and recycled water quality: a comparison of lines of evidence from in vitro, in vivo and chemical analyses.

    Science.gov (United States)

    Leusch, Frederic D L; Khan, Stuart J; Gagnon, M Monique; Quayle, Pam; Trinh, Trang; Coleman, Heather; Rawson, Christopher; Chapman, Heather F; Blair, Palenque; Nice, Helen; Reitsema, Tarren

    2014-03-01

    We investigated water quality at an advanced water reclamation plant and three conventional wastewater treatment plants using an "ecotoxicity toolbox" consisting of three complementary analyses (chemical analysis, in vitro bioanalysis and in situ biological monitoring), with a focus on endocrine disruption. The in vitro bioassays were chosen to provide an appropriately wide coverage of biological effects relevant to managed aquifer recharge and environmental discharge of treated wastewater, and included bioassays for bacterial toxicity (Microtox), genotoxicity (umuC), photosynthesis inhibition (Max-I-PAM) and endocrine effects (E-SCREEN and AR-CALUX). Chemical analysis of hormones and pesticides using LCMSMS was performed in parallel to correlate standard analytical methods with the in vitro assessment. For two plants with surface water discharge into open drains, further field work was carried out to examine in situ effects using mosquitofish (Gambusia holbrooki) as a bioindicator species for possible endocrine effects. The results show considerable cytotoxicity, phytotoxicity, estrogenicity and androgenicity in raw sewage, all of which were significantly reduced by conventional wastewater treatment. No biological response was detected to RO water, suggesting that reverse osmosis is a significant barrier to biologically active compounds. Chemical analysis and in situ monitoring revealed trends consistent with the in vitro results: chemical analysis confirmed the removal trends observed by the bioanalytical tools, and in situ sampling did not reveal any evidence of endocrine disruption specifically due to discharge of treated wastewater (although other sources may be present). Biomarkers of exposure (in vitro) and effect (in vivo or in situ) are complementary and together provide information with a high level of ecological relevance. This study illustrates the utility of combining multiple lines of evidence in the assessment of water quality. Copyright

  20. Preparation and Characterization of Conducting Polymer Latices by Chemical Polymerization of Aniline or Anisidine in Presence of Latex: Study of Their Electroactivity and Anti-Corrosion Properties

    Directory of Open Access Journals (Sweden)

    Bakhshali Massoumi

    2013-06-01

    Full Text Available Poly (vinylacetate-co-butylmethacrylate was prepared in presence of potassium persulphate as an oxidizing agent in aqueous solution of dodecylbenzene sulfonate sodium as an emulsifying agent. Then, aniline was polymerized by chemical oxidation method at three different concentrations of aniline monomer (0.1, 0.2 and 0.3 M in toluene in presence of poly(vinylacetate-co-butylmethacrylate in order to obtain polyaniline/poly(vinylacetate-co-butylmethacrylate. To prepare conducting-latex of polyanisidine/poly(vinylacetate-co-butylmethacrylate the same method was employed as above for aniline monomer in obtaining conducting polyaniline/poly(vinylacetate-co-butylmethacrylate latex. In addition, the purification of conducting-latex polymers, polyaniline/poly(vinylacetate-co-butylmethacrylate and polyanisidine/poly(vinylacetate-co-butylmethacrylate was conducted and preparation of tin layer films of conducting-latex polymers was carried out by casting method on glassy lames. The electroactivity properties of the prepared latex-polymers, polyaniline/poly(vinylacetate-co-butylmethacrylate and polyanisidine/poly(vinylacetate-co-butylmethacrylate were investigated by cyclic voltammetery (CV. The voltamogrames showed that the latex films were electroactive. Because of conductivity and electroactivity, the obtained films may find applications in anti-corrosion coatings. The anti-corrosion properties of conducting-latex polymers were studied on aluminum surface by impedance technique. The structure of the prepared conducting-latex polymers was confirmed by Fourier transform infrared (FTIR. Finally, the electrical conductivity of synthesized conducting-latex polymers, polyaniline/poly(vinylacetate-co-butylmethacrylate and polyanisidine/poly(vinylacetate-co-butylmethacrylate was measured by four probe technique.

  1. Large-Area Chemical Vapor Deposited MoS2 with Transparent Conducting Oxide Contacts toward Fully Transparent 2D Electronics

    KAUST Repository

    Dai, Zhenyu

    2017-09-08

    2D semiconductors are poised to revolutionize the future of electronics and photonics, much like transparent oxide conductors and semiconductors have revolutionized the display industry. Herein, these two types of materials are combined to realize fully transparent 2D electronic devices and circuits. Specifically, a large-area chemical vapor deposition process is developed to grow monolayer MoS2 continuous films, which are, for the first time, combined with transparent conducting oxide (TCO) contacts. Transparent conducting aluminum doped zinc oxide contacts are deposited by atomic layer deposition, with composition tuning to achieve optimal conductivity and band-offsets with MoS2. The optimized process gives fully transparent TCO/MoS2 2D electronics with average visible-range transmittance of 85%. The transistors show high mobility (4.2 cm2 V−1 s−1), fast switching speed (0.114 V dec−1), very low threshold voltage (0.69 V), and large switching ratio (4 × 108). To our knowledge, these are the lowest threshold voltage and subthreshold swing values reported for monolayer chemical vapor deposition MoS2 transistors. The transparent inverters show fast switching properties with a gain of 155 at a supply voltage of 10 V. The results demonstrate that transparent conducting oxides can be used as contact materials for 2D semiconductors, which opens new possibilities in 2D electronic and photonic applications.

  2. Analyses of ionic conductivity and dielectric behavior of solid polymer electrolyte based 2-hydroxyethyl cellulose doped ammonium nitrate plasticized with ethylene carbonate

    Science.gov (United States)

    Hafiza, M. N.; Isa, M. I. N.

    2017-09-01

    A solid polymer electrolyte (SPE) based 2-hydroxyethyl cellulose (2-HEC) doped ammonium nitrate (NH4NO3) plasticized with ethylene carbonate (EC) has been investigated using electrical impedance spectroscopy (EIS). The highest ionic conductivity of (1.17±0.01) × 10-3 Scm-1 was obtained for 2-HEC-NH4NO3 plasticized with 16 wt.% EC. Dielectric and modulus study showed non-Debye type of 2-HEC-NH4NO3-EC SPE.

  3. Addressing the selectivity issue of cobalt doped zinc oxide thin film iso-butane sensors: Conductance transients and principal component analyses

    Science.gov (United States)

    Ghosh, A.; Majumder, S. B.

    2017-07-01

    Iso-butane (i-C4H10) is one of the major components of liquefied petroleum gas which is used as fuel in domestic and industrial applications. Developing chemi-resistive selective i-C4H10 thin film sensors remains a major challenge. Two strategies were undertaken to differentiate carbon monoxide, hydrogen, and iso-butane gases from the measured conductance transients of cobalt doped zinc oxide thin films. Following the first strategy, the response and recovery transients of conductances in these gas environments are fitted using the Langmuir adsorption kinetic model to estimate the heat of adsorption, response time constant, and activation energies for adsorption (response) and desorption (recovery). Although these test gases have seemingly different vapor densities, molecular diameters, and reactivities, analyzing the estimated heat of adsorption and activation energies (for both adsorption and desorption), we could not differentiate these gases unequivocally. However, we have found that the lower the vapor density, the faster the response time irrespective of the test gas concentration. As a second strategy, we demonstrated that feature extraction of conductance transients (using fast Fourier transformation) in conjunction with the pattern recognition algorithm (principal component analysis) is more fruitful to address the cross-sensitivity of Co doped ZnO thin film sensors. We have found that although the dispersion among different concentrations of hydrogen and carbon monoxide could not be avoided, each of these three gases forms distinct clusters in the plot of principal component 2 versus 1 and therefore could easily be differentiated.

  4. Chemical stability of conductive ceramic anodes in LiCl–Li{sub 2}O molten salt for electrolytic reduction in pyroprocessing

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Sung Wook; Kang, Hyun Woo; Jeon, Min Ku; Lee, Sang Kwon; Choi, Eun Young; Park, Woo Shin; Hong, Sun Seok; Oh, Seung Chul; Hur, Jin Mok [Nuclear Fuel Cycle Process Development Group, Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2016-08-15

    Conductive ceramics are being developed to replace current Pt anodes in the electrolytic reduction of spent oxide fuels in pyroprocessing. While several conductive ceramics have shown promising electrochemical properties in small-scale experiments, their long-term stabilities have not yet been investigated. In this study, the chemical stability of conductive La{sub 0.33}Sr{sub 0.67}MnO{sub 3} in LiCl–Li{sub 2}O molten salt at 650°C was investigated to examine its feasibility as an anode material. Dissolution of Sr at the anode surface led to structural collapse, thereby indicating that the lifetime of the La{sub 0.33}Sr{sub 0.67}MnO{sub 3} anode is limited. The dissolution rate of Sr is likely to be influenced by the local environment around Sr in the perovskite framework.

  5. Zero percolation threshold in electric conductivity of aluminum nanowire network fabricated by chemical etching using an electrospun nanofiber mask

    Science.gov (United States)

    Azuma, Keisuke; Sakajiri, Koichi; Okabe, Takashi; Matsumoto, Hidetoshi; Kang, Sungmin; Watanabe, Junji; Tokita, Masatoshi

    2017-09-01

    We investigated the sheet resistance (R s) and transmittance (T) of seamless two-dimensional networks of 50-nm-thick aluminum (Al) nanowires (NWs) with widths (W) ranging from 380 to 1410 nm. The Al NWs were fabricated by wet-etching of Al metalized polyester films with using polystyrene (PS) nanofibers as the mask. The PS nanofibers were deposited by the electrospinning of a PS solution and adhered to the film by annealing. W and the area coverage (φ) were increased with increasing PS solution concentration and deposition time, respectively. With increasing φ from 3 to 34%, T and R s decreased from 99 to 75% and from 800 to 10 Ω/sq, respectively, and the network with W = 878 nm at φ = 0.21 attained values of T = 91% and R s = 31 Ω/sq. The conductivity increases with φ with an exponent of 2, demonstrating that seamless NW networks are characterized by the zero percolation threshold.

  6. Applying Data Mining Techniques to Chemical Analyses of Pre-drill Groundwater Samples within the Marcellus Formation Shale Play in Bradford County, Pennsylvania

    Science.gov (United States)

    Wen, T.; Niu, X.; Gonzales, M. S.; Li, Z.; Brantley, S.

    2017-12-01

    Groundwater samples are collected for chemical analyses by shale gas industry consultants in the vicinity of proposed gas wells in Pennsylvania. These data sets are archived so that the chemistry of water from homeowner wells can be compared to chemistry after gas-well drilling. Improved public awareness of groundwater quality issues will contribute to designing strategies for both water resource management and hydrocarbon exploration. We have received water analyses for 11,000 groundwater samples from PA Department of Environmental Protection (PA DEP) in the Marcellus Shale footprint in Bradford County, PA for the years ranging from 2010 to 2016. The PA DEP has investigated these analyses to determine whether gas well drilling or other activities affected water quality. We are currently investigating these analyses to look for patterns in chemistry throughout the study area (related or unrelated to gas drilling activities) and to look for evidence of analytes that may be present at concentrations higher than the advised standards for drinking water. Our preliminary results reveal that dissolved methane concentrations tend to be higher along fault lines in Bradford County [1]. Lead (Pb), arsenic (As), and barium (Ba) are sometimes present at levels above the EPA maximum contaminant level (MCL). Iron (Fe) and manganese (Mn) more frequently violate the EPA standard. We find that concentrations of some chemical analytes (e.g., Ba and Mn) are dependent on bedrock formations (i.e., Catskill vs. Lock Haven) while concentrations of other analytes (e.g., Pb) are not statistically significantly distinct between different bedrock formations. Our investigations are also focused on looking for correlations that might explain water quality patterns with respect to human activities such as gas drilling. However, percentages of water samples failing EPA MCL with respect to Pb, As, and Ba have decreased from previous USGS and PSU studies in the 1990s and 2000s. Public access to

  7. Chemical and mineralogical analyses of Roman amphorae from Augustan period recovered at the production center of Sant Antoni de Calonge (Gerona, Spain)

    International Nuclear Information System (INIS)

    Vila Socias, L.; Prats Pico, N.; Buxeda Garrigos, J.

    2016-01-01

    Amphorae were the most popular transport vessels used to ship wine and other commodities in Antiquity. This paper reports the results of the analyses of 38 samples of several Roman amphorae types recovered at Calonge (Gerona, Spain). Chemical composition of individuals have been obtained by means of XRF. Equivalent firing temperatures have been estimated by XRD and further refiring experiments have been performed. The results suggest the existence of two different clay pastes among individuals analyzed, most of which were fired at the range 900-1000 degree centigrade. Moreover, it is argued that craftsmen did not follow highly standardized paste preparation process during the first activity period of the workshop. The results are discussed in terms of production technology and standardization. (Author)

  8. Electron probe micro analyser chemical zircon ages of the Khetri granitoids, Rajasthan, India: records of widespread late palaeoproterozoic extension-related magmatism

    International Nuclear Information System (INIS)

    Kaur, Parampreet; Chaudhri, Naveen; Biju-Sekhar, S.; Yokoyama, K.

    2006-01-01

    A number of granitoid plutons were emplaced in the northernmost entity of the Aravalli craton, the Khetri Copper Belt (KCB). We report here Th-U-Pb electron probe micro analyser chemical ages for zircon and monazite from two granitoid plutons of the north KCB, the Biharipur and Dabla. Zircons occurring in the granitoids depict well-developed magmatic zoning and are chronologically unzoned. Both the plutons and their diverse granitoid facies are coeval and provide ages around 1765-1710 Ma. Geochemical attributes of the studied plutons are typical of A-type within-plate granites and consistent with an extensional tectonic environment. Our new age data are comparable to the petrologically similar A-type granitoids of the Alwar region, which have provided zircon chemical ages around 1780-1710 Ma. These analogous ages imply a widespread late palaeoproterozoic extension-related plutonism in the northern part of the Aravalli craton. The monazites, which were recovered only from the mafic magmatic rocks of the Biharipur pluton, yielded an isochron age of 910 ±10 Ma, signifying an over- print of a younger neoproterozoic thermal event in the region. (author)

  9. Chemical, laboratory analyses, physical and profile oceanographic data collected aboard the JACK FITZ in the Gulf of Mexico from 2010-08-18 to 2010-08-23 in response to the Deepwater Horizon Oil Spill event (NODC Accession 0069119)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Chemical, laboratory analyses, physical and profile oceanographic data were collected aboard the JACK FITZ in the Gulf of Mexico from 2010-08-18 to 2010-08-23 in...

  10. Chemical, laboratory analyses, physical and profile oceanographic data collected aboard the BUNNY BORDELON in the Gulf of Mexico from 2010-08-18 to 2010-08-23 in response to the Deepwater Horizon Oil Spill event (NODC Accession 0069118)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Chemical, laboratory analyses, physical and profile oceanographic data were collected aboard the BUNNY BORDELON in the Gulf of Mexico from 2010-08-18 to 2010-08-23...

  11. Chemical and laboratory analyses oceanographic data collected aboard the Wes Bordelon in the Gulf of Mexico from 2010-08-18 to 2010-08-22 in response to the Deepwater Horizon Oil Spill event (NODC Accession 0074863)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Chemical and laboratory analyses oceanographic data were collected aboard the Wes Bordelon in the Gulf of Mexico from 2010-08-18 to 2010-08-22 in response to the...

  12. Chemical, laboratory analyses, physical and profile oceanographic data collected aboard the JACK FITZ in the Gulf of Mexico from 2010-06-12 to 2010-06-20 in response to the Deepwater Horizon Oil Spill event (NODC Accession 0069074)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Chemical, laboratory analyses, physical and profile oceanographic data were collected aboard the JACK FITZ in the Gulf of Mexico from 2010-06-12 to 2010-06-20 in...

  13. Stomatal conductance at Duke FACE: Leveraging the lessons from 11 years of scaled sap flux measurements for region-wide analyses

    Science.gov (United States)

    Ward, E. J.; Bell, D.; Clark, J. S.; McCarthy, H. R.; Kim, H.; domec, J.; Noormets, A.; McNulty, D.; Sun, G.; Oren, R.

    2013-12-01

    A network of thermal dissipation probes (TDPs) monitoring sap flux density was used to estimate leaf-specific transpiration (EL) and canopy-averaged stomatal conductance (GS) in Pinus taeda (L.) exposed to +200 ppm atmospheric CO2 levels (eCO2) and nitrogen fertilization as part of the Duke FACE study. Data from scaling half-hourly measurements from hundreds of sensors over 11 years indicated that P. taeda in eCO2 intermittently (49% of monthly values) decreased stomatal conductance relative to the control, with a mean reduction of 13% in both total EL and mean daytime GS. This intermittent response was related to changes in a hydraulic allometry index (AH), defined as sapwood area per unit leaf area per unit canopy height, which was linearly related to GS at reference conditions (GSR) during the growing season across years (R2=0.67). Overall, AH decreased a mean of 15% with eCO2 over the course of the study, due mostly to a mean 19% increase in leaf area. Throughout the southeastern U.S., other P. taeda stands have been monitored with TDPs, such as the US-NC2 Ameriflux site and four fertilizer × throughfall displacement studies recently begun as part of the PINEMAP research network in VA, GA, FL and OK. We will also discuss the challenges and benefits of using a common modeling platform to combine FACE TDP data with that from a diversity of sites and treatments to draw inferences about EL and GS responses to environmental drivers and climate change, as well as their relation to AH, across the range of P. taeda.

  14. Effects of chemical intermixing on electrical and thermal contact conductances at metallized bismuth and antimony telluride interfaces

    Energy Technology Data Exchange (ETDEWEB)

    Devender,; Mehta, Rutvik J.; Ramanath, Ganpati, E-mail: Ramanath@rpi.edu [Department of Materials Science and Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180 (United States); Lofgreen, Kelly; Mahajan, Ravi [Intel Corporation, Assembly Test and Technology Development, Chandler, Arizona 85226 (United States); Yamaguchi, Masashi [Department of Physics, Applied Physics and Astronomy, Rensselaer Polytechnic Institute, Troy, New York 12180 (United States); Borca-Tasciuc, Theodorian [Department of Mechanical Aerospace and Nuclear Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180 (United States)

    2015-03-15

    Tailoring electrical and thermal contact conductivities (Σ{sub c} and Γ{sub c}) across metallized pnictogen chalcogenide interfaces is key for realizing efficient thermoelectric devices. The authors report that Cu, Ni, Ti, and Ta diffusion and interfacial telluride formation with n-Bi{sub 2}Te{sub 3} and p-Sb{sub 2}Te{sub 3} influence both Σ{sub c} and Γ{sub c}. Cu metallization yields the highest Γ{sub c} and the lowest Σ{sub c}, correlating with maximal metal diffusion and copper telluride formation. Ni diffuses less and yields the highest Σ{sub c} with Sb{sub 2}Te{sub 3} due to p-type nickel telluride formation, which diminishes Σ{sub c} improvement with n-Bi{sub 2}Te{sub 3} interfaces. Ta and Ti contacts yield the lowest properties similar to that in Ni-metallized structures. These correlations between interfacial diffusion and phase formation on electronic and thermal transport properties will be important for devising suitable metallization for thermoelectric devices.

  15. Chemicals of emerging concern in water and bottom sediment in Great Lakes areas of concern, 2010 to 2011-Collection methods, analyses methods, quality assurance, and data

    Science.gov (United States)

    Lee, Kathy E.; Langer, Susan K.; Menheer, Michael A.; Foreman, William T.; Furlong, Edward T.; Smith, Steven G.

    2012-01-01

    The U.S. Geological Survey (USGS) cooperated with the U.S. Environmental Protection Agency and the U.S. Fish and Wildlife Service on a study to identify the occurrence of chemicals of emerging concern (CECs) in water and bottom-sediment samples collected during 2010–11 at sites in seven areas of concern (AOCs) throughout the Great Lakes. Study sites include tributaries to the Great Lakes in AOCs located near Duluth, Minn.; Green Bay, Wis.; Roches­ter, N.Y.; Detroit, Mich.; Toledo, Ohio; Milwaukee, Wis.; and Ashtabula, Ohio. This report documents the collection meth­ods, analyses methods, quality-assurance data and analyses, and provides the data for this study. Water and bottom-sediment samples were analyzed at the USGS National Water Quality Laboratory in Denver, Colo., for a broad suite of CECs. During this study, 135 environmental and 23 field dupli­cate samples of surface water and wastewater effluent, 10 field blank water samples, and 11 field spike water samples were collected and analyzed. Sixty-one of the 69 wastewater indicator chemicals (laboratory method 4433) analyzed were detected at concentrations ranging from 0.002 to 11.2 micrograms per liter. Twenty-eight of the 48 pharmaceuticals (research method 8244) analyzed were detected at concentrations ranging from 0.0029 to 22.0 micro­grams per liter. Ten of the 20 steroid hormones and sterols analyzed (research method 4434) were detected at concentrations ranging from 0.16 to 10,000 nanograms per liter. During this study, 75 environmental, 13 field duplicate samples, and 9 field spike samples of bottom sediment were collected and analyzed for a wide variety of CECs. Forty-seven of the 57 wastewater indicator chemicals (laboratory method 5433) analyzed were detected at concentrations ranging from 0.921 to 25,800 nanograms per gram. Seventeen of the 20 steroid hormones and sterols (research method 6434) analyzed were detected at concentrations ranging from 0.006 to 8,921 nanograms per gram. Twelve of

  16. The effect of thermal conductivity of the tool electrode in spark-assisted chemical engraving gravity-feed micro-drilling

    International Nuclear Information System (INIS)

    Mousa, M; Allagui, A; Ng, H D; Wüthrich, R

    2009-01-01

    Spark-assisted chemical engraving (SACE) is a non-traditional micro-machining technology based on electrochemical discharge phenomena. In SACE gravity-feed micro-drilling, various parameters including the thermal properties of the tool electrode play a significant role in the process. Based on a series of experiments using tool electrodes with different thermal properties, the effect in SACE gravity-feed micro-drilling is discussed. It is demonstrated that machining with higher thermal conductivity tool electrodes results in faster machining during the discharge regime and slower machining during the hydrodynamic regime of SACE gravity-feed micro-drilling

  17. Electrical conductivity and oxygen exchange kinetics of La2NiO4+delta thin films grown by chemical vapor deposition

    DEFF Research Database (Denmark)

    Garcia, G.; Burriel, M.; Bonanos, Nikolaos

    2008-01-01

    Epitaxial c-axis oriented La2NiO4+delta films were deposited onto SrTiO3 and NdGaO3 substrates by the pulsed injection metal organic chemical vapor deposition technique. Experimental conditions were optimized in order to accurately control the composition, thickness, and texture of the layers. X......-ray diffraction was used to confirm the high crystalline quality of the obtained material. Electrical characterizations were performed on thin (50 nm) and thick (335 nm) layers. The total specific conductivity, which is predominantly electronic, was found to be larger for the thinner films measured (50 nm......), probably due to the effect of the strain present in the layers. Those thin films (50 nm) showed values even larger than those observed for single crystals and, to our knowledge, are the largest conductivity values reported to date for the La2NiO4+delta material. The oxygen exchange kinetics was studied...

  18. Role of post-sulfonation of poly(ether ether sulfone) in proton conductivity and chemical stability of its proton exchange membranes for fuel cell

    Energy Technology Data Exchange (ETDEWEB)

    Unveren, Elif Erdal; Erdogan, Tuba; Inan, Tulay Y. [Chemistry Institute, TUBITAK Marmara Research Center, 41470, Gebze, Kocaeli (Turkey); Celebi, Serdar S. [Professor Emeritus, Chemical Engineering Department, Hacettepe University, 06800, Beytepe, Ankara (Turkey)

    2010-04-15

    Commercially available poly(ether ether sulfone), PEES, was directly sulfonated using concentrated sulfuric acid at low temperatures by minimizing degradation during sulfonation. The sulfonation reaction was performed in the temperature range of 5-25 C. Sulfonated polymers were characterized by FTIR, {sup 1}H NMR spectroscopy and ion exchange capacity (IEC) measurements. Degradation during sulfonation was investigated by measuring intrinsic viscosity, glass transition temperature and thermal decomposition temperature of sulfonated polymers. Sulfonated PEES, SPEES, membranes were prepared by solvent casting method and characterized in terms of IEC, proton conductivity and water uptake. The effect of sulfonation conditions on chemical stability of membranes was also investigated via Fenton test. Optimum sulfonation condition was determined to be 10 C with conc. H{sub 2}SO{sub 4} based on the characteristics of sulfonated polymers and also the chemical stability of their membranes. SPEES membranes exhibited proton conductivity up to 185.8 mS cm{sup -1} which is higher than that of Nafion 117 (133.3 mS cm{sup -1}) measured at 80 C and relative humidity 100%. (author)

  19. Handbook of acute toxicity of chemicals to fish and aquatic invertebrates : summaries of toxicity tests conducted at Columbia National Fisheries Research Laboratory, 1965-78

    Science.gov (United States)

    Johnson, W. Waynon; Finley, Mack T.

    1980-01-01

    substituted. Solvent concentrations did not exceed 0.5 mL/L in final dilution water.Test water (dilution water) was reconstituted from deionized water of at least 106 ohms resistivity by the addition of appropriate reagent grade chemicals (Marking 1969). Water was buffered to maintain a pH of 7.2 to 7.5, an alkalinity of 30 to 35 mg/L, and a hardness of 40 to 50 mg/L as CaCO3. Test water was mixed thoroughly and aerated before transfer into test chambers. Fish were acclimated to dilution water by gradually changing the water in acclimated tanks from 100% well water to 100% reconstituted water over a 1- to 3-day period at the desired testing temperature. Invertebrates were acclimated from well water to dilution water over a 4- to 6-h period. Toxicity tests were conducted under static conditions without aeration, and the organisms were not fed during acclimation or testing. Temperature of test solutions was maintained within ± 1°C of that required for a given test.Toxicity tests with fish were conducted in 18.9-liter (5-gal) wide-mouthed jars containing 15 liters of test solution. Fingerling fish weighing 0.2 to 1.5 g were tested at each concentration. Caution was taken not to exceed 0.8 g of test organisms per liter of solution. Duplicate test chambers were used to accommodate larger fish. Test chambers varied in size for invertebrates, depending on the species used; volume of test solution ranged from 0.25 to 4 liters. At least 10 organisms were exposed to each concentration for all definitive tests. At least six concentrations were used per toxicity test.The tests began upon initial exposure to the toxicant and continued for 96 h. Immobilization tests with invertebrates were conducted for only 48 h. The number of dead or affected organisms in each test chamber were recorded and the dead organisms were removed every 24 h; general observations on the condition of test organisms were also recorded at these times.Toxicity data were analyzed by a statistical method described by

  20. Chemical and ecotoxicological analyses of sediments and elutriates of contaminated rivers due to e-waste recycling activities using a diverse battery of bioassays

    Energy Technology Data Exchange (ETDEWEB)

    Wang, F.; Leung, A.O.W.; Wu, S.C.; Yang, M.S. [Croucher Institute for Environmental Sciences, and Department of Biology, Hong Kong Baptist University, Kowloon Tong (Hong Kong); Wong, M.H., E-mail: mhwong@hkbu.edu.h [Croucher Institute for Environmental Sciences, and Department of Biology, Hong Kong Baptist University, Kowloon Tong (Hong Kong)

    2009-07-15

    A multi-trophic, multi-exposure phase assessment approach was applied to characterize the toxicity of sediments collected from two rivers in Guiyu, China, an e-waste recycling centre. Elutriate toxicity tests (bacterium Vibrio fischeri and microalga Selenastrum capricornutum) and whole sediment toxicity test (crustacean Heterocypris incongruens) showed that most sediments exhibited acute toxicity, due to elevated heavy metals and PAHs levels, and low pH caused by uncontrolled acid discharge. The survival rates of crustaceans were negatively (p < 0.05) correlated with total PAHs in sediments (411-1755 mg kg{sup -1}); EC50s of V. fischeri on the elutriates were significantly correlated with elutriate pH (p < 0.01). Significant (p < 0.05) correlations between the induction of hepatic metallothionein in tilapia (Oreochromis mossambicus) and metal concentrations (Cu, Zn, Pb) in sediments were also observed, when fish were fed with diets containing sediment. The results showed that uncontrolled e-waste recycling activities may bring adverse effects to local aquatic ecosystem. - Toxicity tests using different trophic organisms provided important information, supplementing chemical analyses.

  1. TiO{sub 2} films obtained by microwave-activated chemical-bath deposition used to improve TiO{sub 2}-conducting glass contact

    Energy Technology Data Exchange (ETDEWEB)

    Zumeta, I.; Gonzalez, B. [Institute for Material Science and Technology, University of Havana, Colina Universitaria, Ciudad Habana 10 400 (Cuba); Ayllon, J.A.; Domenech, X. [Chemistry Department, Autonomous University of Barcelona, 08290 Cerdanyola del Valles (Spain); Vigil, E. [Institute for Material Science and Technology, University of Havana, Colina Universitaria, Ciudad Habana 10 400 (Cuba); Physics Faculty, University of Havana, Colina Universitaria, Ciudad Habana 10 400 (Cuba)

    2009-10-15

    In traditional solar cells, metal-semiconductor contacts used to extract photogenerated carriers are very important. In dye-sensitized solar cells (DSSC) not much attention has been given to contact between the TiO{sub 2} and the transparent conducting glass (TCO), which is used instead of a metal contact to extract electrons. TiO{sub 2} layers obtained by microwave-activated chemical-bath deposition (MW-CBD) are proposed to improve TiO{sub 2} contact to conducting glass. Spectra of incident photon to current conversion efficiency (IPCE) are obtained for two-photoelectrode TiO{sub 2} photoelectrochemical cells. IPCE spectra show higher values when TiO{sub 2} double layer photoelectrodes are used. In these, the first layer or contacting layer is made by MW-CBD. Best results are obtained for double layer photoelectrodes on FTO (SnO{sub 2}:F) as conducting oxide substrate. Modeling of IPCE spectra reveals the importance of electrical contact and electron extraction rate at the TiO{sub 2}/TCO interface. (author)

  2. The chemical conditions of the late Archean Hamersley basin inferred from whole rock and pyrite geochemistry with Δ33S and δ34S isotope analyses

    Science.gov (United States)

    Gregory, Daniel D.; Large, Ross R.; Halpin, Jacqueline A.; Steadman, Jeffery A.; Hickman, Arthur H.; Ireland, Trevor R.; Holden, Peter

    2015-01-01

    The well-preserved late Archean sedimentary rocks of the Fortescue and Hamersley Basins in Western Australia offer fascinating insights into early earth ocean chemistry prior to the Great Oxidation Event (GOE). In this study, we use a combination of whole rock geochemistry, LA-ICPMS trace element analysis of sedimentary pyrite and pyrrhotite and SHRIMP-SI sulfur isotope analyses to elucidate the chemical changes in these sedimentary rocks. These proxies are used to examine chemical conditions of the ocean during the late Archean. Two to three periods of oxygen enrichment prior to the deposition of banded iron formations (BIF) can be identified. One minor stage of general increase in whole rock enrichment factors and trace element content of pyrite is observed up stratigraphy in the Jeerinah Formation, Fortescue Basin and a more substantial stage is present in the Paraburdoo and Bee Gorge Members of the Wittenoom Formation, Hamersley Basin. Some of the trace element enrichments indicate organic matter burial flux (Ni, Cr, Zn, Co and Cu) which suggests an increase in biological productivity. If the increased biological activity reflects an increase in cyanobacteria activity then an associated increase in oxygen is likely to have occurred during the deposition of the Bee Gorge Member. An increase in atmospheric oxygen would result in continental weathering of sulfide and other minerals, increasing the trace element content of the water column via erosion and avoiding excessive depletion of trace elements due to drawdown in seawater. Since some of these trace elements may also be limiting nutrients (such as Mo and Se) for the cyanobacteria, the degree of biological productivity may have further increased due to the increasing amount of trace elements introduced by oxygenation in a positive feedback loop. These periods of increased productivity and oxygen rise stopped prior to the onset of BIF deposition in the Hamersley Basin. This may be due to the ocean reaching an

  3. Analyses and estimates of hydraulic conductivity from slug tests in alluvial aquifer underlying Air Force Plant 4 and Naval Air Station-Joint Reserve Base Carswell Field, Fort Worth, Texas

    Science.gov (United States)

    Houston, Natalie A.; Braun, Christopher L.

    2004-01-01

    This report describes the collection, analyses, and distribution of hydraulic-conductivity data obtained from slug tests completed in the alluvial aquifer underlying Air Force Plant 4 and Naval Air Station-Joint Reserve Base Carswell Field, Fort Worth, Texas, during October 2002 and August 2003 and summarizes previously available hydraulic-conductivity data. The U.S. Geological Survey, in cooperation with the U.S. Air Force, completed 30 slug tests in October 2002 and August 2003 to obtain estimates of horizontal hydraulic conductivity to use as initial values in a ground-water-flow model for the site. The tests were done by placing a polyvinyl-chloride slug of known volume beneath the water level in selected wells, removing the slug, and measuring the resulting water-level recovery over time. The water levels were measured with a pressure transducer and recorded with a data logger. Hydraulic-conductivity values were estimated from an analytical relation between the instantaneous displacement of water in a well bore and the resulting rate of head change. Although nearly two-thirds of the tested wells recovered 90 percent of their slug-induced head change in less than 2 minutes, 90-percent recovery times ranged from 3 seconds to 35 minutes. The estimates of hydraulic conductivity range from 0.2 to 200 feet per day. Eighty-three percent of the estimates are between 1 and 100 feet per day.

  4. Chemical sensors

    International Nuclear Information System (INIS)

    Hubbard, C.W.; Gordon, R.L.

    1987-05-01

    The revolution in analytical chemistry promised by recent developments in the field of chemical sensors has potential for significant positive impact on both research and production activities conducted by and for the Department of Energy. Analyses which were, in the past, performed only with a roomful of expensive equipment can now be performed with miniature solid-state electronic devices or small optical probes. Progress in the development of chemical sensors has been rapid, and the field is currently growing at a great rate. In accordance, Pacific Northwest Laboratory initiated a survey of recent literature so that contributors to active programs in research on analytical methods could be made aware of principles and applications of this new technology. This report presents the results of that survey. The sensors discussed here are divided into three types: micro solid-state devices, optical sensors, and piezoelectric crystal devices. The report is divided into three corresponding sections. The first section, ''Micro Solid-State Devices,'' discusses the design, operation, and application of electronic sensors that are produced in much the same way as standard solid-state electronic devices. The second section, ''Optrodes,'' covers the design and operation of chemical sensors that use fiber optics to detect chemically induced changes in optical properties. The final section, ''Piezoelectric Crystal Detectors,'' discusses two types of chemical sensors that depend on the changes in the properties of an oscillating piezoelectric crystal to detect the presence of certain materials. Advantages and disadvantages of each type of sensor are summarized in each section

  5. Studies on electrical conduction behavior of La1-3xCaxBaxSrxMnO3 synthesized by chemical route

    International Nuclear Information System (INIS)

    Rai, A.K.; Parkash, O.; Mandal, K.D.

    2008-01-01

    In the manganite La 1-x M x MnO 3 (M=Ca,Ba,Sr) the doping concentration introduces a mixed valency (Mn 3+ , Mn 4+ ) which governs the magnetic and electrical properties of the compound. The perovskite oxides La 1-3x Ca x Ba x Sr x MnO 3 (x=0.00,0.05,0.10) were prepared by chemical method. Single-phase formation is confirmed by XRD studies. The electrical behavior of compositions with x=0.00, 0.05 and 0.10 in the system La 1-3x Ca x Ba x Sr x MnO 3 was studied in the temperature range 300-420 K. It is observed that conductivity decreases with increasing temperature as well as dopants concentration. Metallic behavior of these compositions decreases with increasing dopants concentration (x). The microstructures of these samples have been characterized using scanning electron microscopy (SEM). (copyright 2007 WILEY -VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

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

    KAUST Repository

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

    2014-01-01

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

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

    KAUST Repository

    Kedia, Kushal S.

    2014-09-01

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

  8. Vanadium NMR Chemical Shifts of (Imido)vanadium(V) Dichloride Complexes with Imidazolin-2-iminato and Imidazolidin-2-iminato Ligands: Cooperation with Quantum-Chemical Calculations and Multiple Linear Regression Analyses.

    Science.gov (United States)

    Yi, Jun; Yang, Wenhong; Sun, Wen-Hua; Nomura, Kotohiro; Hada, Masahiko

    2017-11-30

    The NMR chemical shifts of vanadium ( 51 V) in (imido)vanadium(V) dichloride complexes with imidazolin-2-iminato and imidazolidin-2-iminato ligands were calculated by the density functional theory (DFT) method with GIAO. The calculated 51 V NMR chemical shifts were analyzed by the multiple linear regression (MLR) analysis (MLRA) method with a series of calculated molecular properties. Some of calculated NMR chemical shifts were incorrect using the optimized molecular geometries of the X-ray structures. After the global minimum geometries of all of the molecules were determined, the trend of the observed chemical shifts was well reproduced by the present DFT method. The MLRA method was performed to investigate the correlation between the 51 V NMR chemical shift and the natural charge, band energy gap, and Wiberg bond index of the V═N bond. The 51 V NMR chemical shifts obtained with the present MLR model were well reproduced with a correlation coefficient of 0.97.

  9. Weld region corrosion during chemical cleaning of PWR [pressurized-water reactor] steam generators: Volume 2, Tests and analyses: Final report

    International Nuclear Information System (INIS)

    Barna, J.L.; Bozeka, S.A.; Jevec, J.M.

    1987-07-01

    The potential for preferential corrosion of steam generator weld regions during chemical cleaning using the generic SGOG solvents was investigated. The investigations included development and use of a corrosion assessment test facility which measured corrosion currents in a realistic model of the steam generator geometry in the vicinity of a specific weld during a simulated chemical dissolution of sludge consisting of essentially pure magnetite. A corrosion monitoring technique was developed and qualified. In this technique free corrosion rates measured by linear polarization techniques are added to corrosion rates calculated from galvanic current measured using a zero resistance ammeter to give an estimate of total corrosion rate for a galvanically corroding material. An analytic modeling technique was developed and proved useful in determining the size requirements for the weld region mockup used in the corrosion assessment test facility. The technique predicted galvanic corrosion rates consistent with that observed in a corrosion assessement test when polarization data used as model input were obtained on-line during the test. The test results obtained during this investigation indicated that chemical cleaning using the SGOG magnetite dissolution solvent can be performed with a small amount of corrosion of secondary side internals and pressure boundary welds. The maximum weld region corrosion measured during a typical chemical cleaning cycle to remove essentially pure magnetite sludge was about 8 mils. However, additional site specific weld region corrosion assessment testing and qualification will be required prior to chemical cleaning steam generators at a specific plant. Recommendations for site specific qualification of chemical cleaning processes and for use of process monitors and on-line corrosion instrumentation are included in this report

  10. A Tutorial for Analysing the Cost-effectiveness of Alternative Methods for Assessing Chemical Toxicology: The Case of Acute Oral Toxicity Prediction

    NARCIS (Netherlands)

    Norlen, H.; Worth, A.P.; Gabbert, S.G.M.

    2014-01-01

    Compared with traditional animal methods for toxicity testing, in vitro and in silico methods are widely considered to permit a more cost-effective assessment of chemicals. However, how to assess the cost-effectiveness of alternative methods has remained unclear. This paper offers a user-oriented

  11. Investigations on neurotoxicity of chemical substances at the workplace. VII. Longitudinal study with determination of nerve conduction velocities in persons occupationally exposed to styrene

    Energy Technology Data Exchange (ETDEWEB)

    Triebig, G.; Schaller, K.H.; Valentin, H.

    1985-01-01

    The aim of this longitudinal study was to investigate whether long-term exposure to styrene is associated with functional disorders of the peripheral nervous system. Eleven workers (age: 24 to 54 years) of a polyester resin boat industry were studied neurophysiologically and biochemically in 1980 and 1983. The duration of styrene-exposure varied from 3 to 7 years, with a median of 4 years. The control group was comprised of 11 non-styrene-exposed workers of similar age. Air Monitoring with passive samplers was performed on different days for each person. The mean styrene concentrations were 114, 97 and 92 ppm respectively and therefore in the magnitude of the current MAK-value of 100 ppm in the Federal Republic of Germany (FRG). For Biological Monitoring styrene in blood (S-B) and mandelic acid (MA) as well as phenylglyoxylic-acid (PGA) in urine were determined in post-shift samples. The median values for MA at four different sampling times were 816, 1660, 1101 and 1224 mg/g creatinine and for PGA 200, 273, 342 and 336 mg/g creatinine respectively. These levels were below the current Biologischer Arbeitsstoff Toleranzwert (BAT-Wert) for MA (2000 mg/l) and MA + PGA (2500 mg/l). The S-B concentrations ranged from 0.05 mg/l to 3.26 mg/l, with mean values of 0.92 and 0.70 mg/l. The nerve conduction velocities (NCV) of motor and sensory nerve fibers (N. ulnaris and/or N. medianus) showed no significant differences between styrene-exposed workers and age-matched control persons. There were no hints of dose-effect-relationships by correlation analyses. Furthermore the follow-up determination revealed no significant changes regarding NCV.

  12. Results of chemical analyses of soil, shale, and soil/shale extract from the Mancos Shale formation in the Gunnison Gorge National Conservation Area, southwestern Colorado, and at Hanksville, Utah

    Science.gov (United States)

    Tuttle, Michele L.W.; Fahy, Juli; Grauch, Richard I.; Ball, Bridget A.; Chong, Geneva W.; Elliott, John G.; Kosovich, John J.; Livo, Keith E.; Stillings, Lisa L.

    2007-01-01

    Results of chemical and some isotopic analyses of soil, shale, and water extracts collected from the surface, trenches, and pits in the Mancos Shale are presented in this report. Most data are for sites on the Gunnison Gorge National Conservation Area (GGNCA) in southwestern Colorado. For comparison, data from a few sites from the Mancos landscape near Hanksville, Utah, are included. Twelve trenches were dug on the GGNCA from which 258 samples for whole-rock (total) analyses and 187 samples for saturation paste extracts were collected. Sixteen of the extract samples were duplicated and subjected to a 1:5 water extraction for comparison. A regional soil survey across the Mancos landscape on the GGNCA generated 253 samples for whole-rock analyses and saturation paste extractions. Seventeen gypsum samples were collected on the GGNCA for sulfur and oxygen isotopic analysis. Sixteen samples were collected from shallow pits in the Mancos Shale near Hanksville, Utah.

  13. Cell cycle analyses with a pulse cytophotometer: the effect of chemical and physical noxae on the kinetics of the proliferation of tumor cells

    International Nuclear Information System (INIS)

    Goehde, W.

    The following studies were conducted on Ehrlich ascites tumor cells using the pulse cytophotometer: rate of DNA synthesis during the S phase; the effect of cytostatic drugs, endoxan, bleomycin, and other antibiotics on cell kinetics; and effects of x radiation and 1 to 6 MeV neutrons on cell kinetics

  14. Inhibition of precipitation of carbonate apatite by trisodium citrate analysed in base of the formation of chemical complexes in growth solution

    Energy Technology Data Exchange (ETDEWEB)

    Prywer, Jolanta, E-mail: jolanta.prywer@p.lodz.pl [Institute of Physics, Lodz University of Technology, ul. Wólczańska 219, 93-005 Łódź (Poland); Olszynski, Marcin [Institute of Physics, Lodz University of Technology, ul. Wólczańska 219, 93-005 Łódź (Poland); Mielniczek-Brzóska, Ewa [Institute of Chemistry, Environment Protection and Biotechnology, Jan Długosz University of Częstochowa, ul. Armii Krajowej 13/15, 42-200 Częstochowa (Poland)

    2015-11-15

    Effect of trisodium citrate on the precipitation of carbonate apatite is studied. The experimental series are performed in the solution of artificial urine. The investigations are related to infectious urinary stones formation as carbonate apatite is one of the main components of this kind of stones. To mimic a real infection in urinary tract the aqueous ammonia solution was added to the solution of artificial urine. The spectrophotometric results demonstrate that trisodium citrate increases induction time with respect to carbonate apatite formation and decreases the efficiency of carbonate apatite precipitation. The inhibitory effect of trisodium citrate on the precipitation of carbonate apatite is explained in base of chemical speciation analysis. Such an analysis demonstrates that the inhibitory effect is mainly related with the fact that trisodium citrate binds Ca{sup 2+} ions and causes the formation of CaCit{sup −} and Ca{sub 10}(PO{sub 4}){sub 6}CO{sub 3} complexes. Trisodium citrate binds Ca{sup 2+} ions in the range of pH from 6 to 9.5 for which carbonate apatite is favored to be formed. - Highlights: • Trisodium citrate (TC) increases induction time of carbonate apatite (CA) formation. • TC decreases the efficiency of CA precipitation. • The inhibitory effect of TC is explained in base of chemical speciation analysis. • The inhibitory effect is mainly related with the fact that TC binds Ca{sup 2+} ions. • TC binds Ca{sup 2+} ions in the range of pH from 6 to 9.5 for which CA is formed.

  15. An easily sintered, chemically stable, barium zirconate-based proton conductor for high-performance proton-conducting solid oxide fuel cells

    KAUST Repository

    Sun, Wenping; Shi, Zhen; Liu, Mingfei; Bi, Lei; Liu, Wei

    2014-01-01

    Yttrium and indium co-doped barium zirconate is investigated to develop a chemically stable and sintering active proton conductor for solid oxide fuel cells (SOFCs). BaZr0.8Y0.2-xInxO3- δ possesses a pure cubic perovskite structure. The sintering

  16. Chemical characterization of Azadirachta indica grafted on Melia azedarach and analyses of azadirachtin by HPLC-MS-MS (SRM) and meliatoxins by MALDI-MS.

    Science.gov (United States)

    Forim, Moacir Rossi; Cornélio, Vivian Estevam; da Silva, M Fátima das G F; Rodrigues-Filho, Edson; Fernandes, João B; Vieira, Paulo C; Matinez, Sueli Souza; Napolitano, Michael P; Yost, Richard A

    2010-01-01

    Melia azedarach adapted to cool climates was selected as rootstocks for vegetative propagation of Azadirachta indica. Cleft grafting of A. indica on M. azedarach rootstock showed excellent survival. Little is known about the chemistry of grafting. The roots, stems, leaves and seeds of this graft were examined in order to verify if grafted A. indica would produce limonoids different from those found in non-grafted plants. Intact matured fruits were also studied to verify if they were free of meliatoxins. After successive chromatographic separations the extracts afforded several limonoids. HPLC-MS/MS and MALDI-MS were used to develop sensitive methods for detecting azadirachtin on all aerial parts of this graft and meliatoxins in fruits, respectively. The stem afforded the limonoid salannin, which was previously found in the oil seeds of A. indica. Salannin is also found in the root bark of M. azedarach. Thus, the finding of salannin in this study suggests that it could have been translocated from the M. azedarach rootstock to the A. indica graft. HPLC-MS/MS analyses showed that azadirachtin was present in all parts of the fruits, stem, flowers and root, but absent in the leaves. The results of MALDI-MS analyses confirmed the absence of meliatoxins in graft fruits. This study showed that A. indica grafted onto M. azedarach rootstock produces azadirachtin, and also that its fruits are free of meliatoxins from rootstocks, confirming that this graft forms an excellent basis for breeding vigorous Neem trees in cooler regions.

  17. The use of chemical analyses of borehole samples in sub-surface mapping: an example of the Delmas-Bapsfontein area is given

    International Nuclear Information System (INIS)

    Rudman, R.A.

    1989-01-01

    The East Rand Dolomites around Delmas-Bapsfontein underlie an area of about 1000 sq. km. but do not outcrop. An intensive ground water exploration programme had been carried out and the percussion samples obtained were analysed in an attempt to differentiate the sub-surface geology based on the chemistry of the samples. The gross chemistry of the various rock types has been well defined and various computer-aided graphical methods were used to highlight changes in the chemistry. Samples were analysed by means of x-ray fluorescence. The chert-rich dolomite formations near surface have been leached to the extent that all of the carbonate minerals have been removed, leaving a chert residium of commonly 80 m thick. The carbonates in this area can be regarded as 'pure' dolomites. There are however two discretely different CaO/MgO ratios present in the study area. Intrusives with up to 16% Na 2 O are noted. The effect of de-dolomitization at the contacts of the intrusives is clearly illustrated. 4 refs., 7 figs., 1 tab

  18. Single-molecule conductance of a chemically modified, π-extended tetrathiafulvalene and its charge-transfer complex with F4TCNQ

    Directory of Open Access Journals (Sweden)

    Raúl García

    2015-06-01

    Full Text Available We describe the synthesis and single-molecule electrical transport properties of a molecular wire containing a π-extended tetrathiafulvalene (exTTF group and its charge-transfer complex with F4TCNQ. We form single-molecule junctions using the in situ break junction technique using a homebuilt scanning tunneling microscope with a range of conductance between 10 G0 down to 10−7 G0. Within this range we do not observe a clear conductance signature of the neutral parent molecule, suggesting either that its conductance is too low or that it does not form a stable junction. Conversely, we do find a clear conductance signature in the experiments carried out on the charge-transfer complex. Due to the fact we expected this species to have a higher conductance than the neutral molecule, we believe this supports the idea that the conductance of the neutral molecule is very low, below our measurement sensitivity. This idea is further supported by theoretical calculations. To the best of our knowledge, these are the first reported single-molecule conductance measurements on a molecular charge-transfer species.

  19. Risk assessment of PCDD/Fs levels in human tissues related to major food items based on chemical analyses and micro-EROD assay.

    Science.gov (United States)

    Tsang, H L; Wu, S C; Wong, C K C; Leung, C K M; Tao, S; Wong, M H

    2009-10-01

    Nine groups of food items (freshwater fish, marine fish, pork, chicken, chicken eggs, leafy, non-leafy vegetables, rice and flour) and three types of human samples (human milk, maternal serum and cord serum) were collected for the analysis of PCDD/Fs. Results of chemical analysis revealed PCDD/Fs concentrations (pg g(-1) fat) in the following ascending order: pork (0.289 pg g(-1) fat), grass carp (Ctenopharyngodon idellus) (freshwater fish) (0.407), golden thread (Nemipterus virgatus) (marine fish) (0.511), chicken (0.529), mandarin fish (Siniperca kneri) (marine fish) (0.535), chicken egg (0.552), and snubnose pompano (Trachinotus blochii) (marine fish) (1.219). The results of micro-EROD assay showed relatively higher PCDD/Fs levels in fish (2.65 pg g(-1) fat) when compared with pork (0.47), eggs (0.33), chicken (0.13), flour (0.07), vegetables (0.05 pg g(-1) wet wt) and rice (0.05). The estimated average daily intake of PCDD/Fs of 3.51 pg EROD-TEQ/kg bw/day was within the range of WHO Tolerable Daily Intake (1-4 pg WHO-TEQ/kg bw/day) and was higher than the Provisional Tolerable Daily Intake (PMTL) (70 pg for dioxins and dioxin-like PCBs) recommended by the Joint FAO/WHO Expert Committee on Food Additives (JECFA) [Joint FAO/WHO Expert Committee on Food Additives (JECFA), Summary and conclusions of the fifty-seventh meeting, JECFA, 2001.]. Nevertheless, the current findings were significantly lower than the TDI (14 pg WHO-TEQ/kg/bw/day) recommended by the Scientific Committee on Food of the Europe Commission [European Scientific Committee on Food (EU SCF), Opinions on the SCF on the risk assessment of dioxins and dioxin-like PCBs in food, 2000.]. However, it should be noted that micro-EROD assay overestimates the PCDD/Fs levels by 2 to 7 folds which may also amplify the PCDD/Fs levels accordingly. Although the levels of PCDD/Fs obtained from micro-EROD assay were much higher than those obtained by chemical analysis by 2 to 7 folds, it provides a cost-effective and

  20. Early diagenesis of mangrove leaves in a tropical estuary: Bulk chemical characterization using solid-state 13C NMR and elemental analyses

    Science.gov (United States)

    Benner, Ronald; Hatcher, Patrick G.; Hedges, John I.

    1990-07-01

    Changes in the chemical composition of mangrove ( Rhizophora mangle) leaves during decomposition in tropical estuarine waters were characterized using solid-state 13C nuclear magnetic resonance (NMR) and elemental (CHNO) analysis. Carbohydrates were the most abundant components of the leaves accounting for about 50 wt% of senescent tissues. Tannins were estimated to account for about 20 wt% of leaf tissues, and lipid components, cutin, and possibly other aliphatic biopolymers in leaf cuticles accounted for about 15 wt%. Carbohydrates were generally less resistant to decomposition than the other constituents and decreased in relative concentration during decomposition. Tannins were of intermediate resistance to decomposition and remained in fairly constant proportion during decomposition. Paraffinic components were very resistant to decomposition and increased in relative concentration as decomposition progressed. Lignin was a minor component of all leaf tissues. Standard methods for the colorimetric determination of tannins (Folin-Dennis reagent) and the gravimetric determination of lignin (Klason lignin) were highly inaccurate when applied to mangrove leaves. The N content of the leaves was particularly dynamic with values ranging from 1.27 wt% in green leaves to 0.65 wt% in senescent yellow leaves attached to trees. During decomposition in the water the N content initially decreased to 0.51 wt% due to leaching, but values steadily increased thereafter to 1.07 wt% in the most degraded leaf samples. The absolute mass of N in the leaves increased during decomposition indicating that N immobilization was occurring as decomposition progressed.

  1. The Chemical Decomposition of 5-aza-2′-deoxycytidine (Decitabine): Kinetic Analyses and Identification of Products by NMR, HPLC, and Mass Spectrometry

    Science.gov (United States)

    Rogstad, Daniel K.; Herring, Jason L.; Theruvathu, Jacob A.; Burdzy, Artur; Perry, Christopher C.; Neidigh, Jonathan W.; Sowers, Lawrence C.

    2014-01-01

    The nucleoside analog 5-aza-2′-deoxycytidine (Decitabine, DAC) is one of several drugs in clinical use that inhibit DNA methyltransferases, leading to a decrease of 5-methylcytosine in newly replicated DNA and subsequent transcriptional activation of genes silenced by cytosine methylation. In addition to methyltransferase inhibition, DAC has demonstrated toxicity and potential mutagenicity, and can induce a DNA-repair response. The mechanisms accounting for these events are not well understood. DAC is chemically unstable in aqueous solutions, but there is little consensus between previous reports as to its half-life and corresponding products of decomposition at physiological temperature and pH, potentially confounding studies on its mechanism of action and long-term use in humans. Here we have employed a battery of analytical methods to estimate kinetic rates and to characterize DAC decomposition products under conditions of physiological temperature and pH. Our results indicate that DAC decomposes into a plethora of products, formed by hydrolytic opening and deformylation of the triazine ring, in addition to anomerization and possibly other changes in the sugar ring structure. We also discuss the advantages and problems associated with each analytical method used. The results reported here will facilitate ongoing studies and clinical trials aimed at understanding the mechanisms of action, toxicity, and possible mutagenicity of DAC and related analogs. PMID:19480391

  2. Quantum chemical study, spectroscopic investigations, NBO and HOMO-LUMO analyses of 3-aminoquinoline (3AQ) and [Ag(3AQ)2(TCA)] complex (TCA = Trichloroacetate)

    Science.gov (United States)

    Soliman, Saied M.; Kassem, Taher S.; Badr, Ahmed M. A.; Abu Youssef, Morsy A.; Assem, Rania

    2014-09-01

    The new [Ag(3AQ)2(TCA)]; (3AQ = 3-aminoquinoline and TCA = Trichloroacetate) complex is synthesized and characterized using elemental analysis, FTIR, NMR and mass spectroscopy. The molecular geometry, vibrational frequencies, gauge-including atomic orbital (GIAO) 1H chemical shift values of the free and coordinated 3AQ in the ground state have been calculated by using DFT/B3LYP method. The TD-DFT results of the [Ag(3AQ)2(TCA)] complex showed a π-π* transition band at 240.3-242.6 nm (f = 0.1334-0.1348) which has longer wavelength and lower absorption intensity than that for the free 3AQ (233.2 nm, f = 0.3958). Dipole moment, polarizability and HOMO-LUMO gap values predicted better nonlinear optical properties (NLO) for the [Ag(3AQ)2(TCA)] than the 3AQ ligand. NBO analysis has been used to predict the most accurate Lewis structure of the studied molecules. The energies of the different intramolecular charge transfer (ICT) interactions within the studied molecules were estimated using second order perturbation theory.

  3. Testing REACH draft technical guidance notes for conducting chemical safety assessments-the experience of a downstream user of a preparation.

    Science.gov (United States)

    Gade, Anne Lill; Ovrebø, Steinar; Hylland, Ketil

    2008-07-01

    The goal of REACH is the safe use of chemicals. This study examines the efficiency and usefulness of two draft technical guidance notes in the REACH Interim Project 3.2-2 for the development of the chemical safety report and exposure scenarios. A case study was carried out for a paint system for protection of structural steel. The focuses of the study were risk assessment of preparations based on Derived No Effect Level (DNEL) and Predicted No Effect Concentrations (PNEC) and on effective and accurate communication in the supply chain. Exposure scenarios and generic descriptions of uses, risk management measures, and exposure determinants were developed. The study showed that communication formats, software tools, and guidelines for chemical risk assessment need further adjustment to preparations and real-life situations. Web platforms may simplify such communication. The downstream formulator needs basic substance data from the substance manufacturer during the pre-registration phase to develop exposure scenarios for preparations. Default values need to be communicated in the supply chain because these were critical for the derivation of applicable risk management demands. The current guidelines which rely on the available toxicological knowledge are insufficient to advise downstream users on how to develop exposure scenarios for preparations.

  4. Synthesis, spectroscopic analyses (FT-IR and NMR), vibrational study, chemical reactivity and molecular docking study and anti-tubercular activity of condensed oxadiazole and pyrazine derivatives

    Science.gov (United States)

    El-Azab, Adel S.; Mary, Y. Sheena; Abdel-Aziz, Alaa A. M.; Miniyar, Pankaj B.; Armaković, Stevan; Armaković, Sanja J.

    2018-03-01

    The Fourier transform infrared spectra of the compounds 2-(5-phenyl-1,3,4-oxadiazol-2-yl)pyrazine (PHOXPY), 2-(5-styryl-1,3,4-oxadiazol-2-yl)pyrazine (STOXPY) and 2-(5-(furan-2-yl)-1,3,4-oxadiazol-2-yl)pyrazine (FUOXPY) have been recorded and the wavenumbers are computed at the density functional theory level. The assignments of all the fundamental bands of each molecule are made using potential energy distribution. The computed values of dipole moment, polarizability and hyperpolarizability values indicate that the title molecules exhibit NLO properties. The HOMO and LUMO energies demonstrate the chemical stability of the molecules and NBO analysis is made to study the stability of molecules arising from hyper conjugative interactions and charge delocalization. Detailed computational analysis and spectroscopic characterization has been performed for three newly synthesized oxadiazole derivatives. Obtained computational and experimental results have been mutually compared in order to understand the influence of structural parts specific for each derivative. From the MIC determination, MTb H37Rv was found to be sensitive to compounds, PHOXPY, STOXPY and FUOXPY. The results obtained from anti-TB activity are more promising as the compounds were found to be more potent than reference standards, streptomycin and pyrazinamide. Efforts were made in order to predict both global and local reactive properties of the title oxadiazole derivatives, including their sensitivity towards autoxidation mechanism and influence of water. The results obtained from anti-TB activity are more promising for the title compounds. Interaction with representative protein Pterindeaminase inhibitor asricin A was also investigated using the molecular docking procedure. The docked ligands form stable complexes with the receptor ricin A and the docking results suggest that these compounds can be developed as new anti-cancer drugs.

  5. Changes in lead and zinc lability during weathering-induced acidification of desert mine tailings: Coupling chemical and micro-scale analyses

    International Nuclear Information System (INIS)

    Hayes, Sarah M.; White, Scott A.; Thompson, Thomas L.; Maier, Raina M.; Chorover, Jon

    2009-01-01

    Desert mine tailings may accumulate toxic metals in the near surface centimeters because of low water through-flux rates. Along with other constraints, metal toxicity precludes natural plant colonization even over decadal time scales. Since unconsolidated particles can be subjected to transport by wind and water erosion, potentially resulting in direct human and ecosystem exposure, there is a need to know how the lability and form of metals change in the tailings weathering environment. A combination of chemical extractions, X-ray diffraction, micro-X-ray fluorescence spectroscopy, and micro-Raman spectroscopy were employed to study Pb and Zn contamination in surficial arid mine tailings from the Arizona Klondyke State Superfund Site. Initial site characterization indicated a wide range in pH (2.5-8.0) in the surficial tailings pile. Ligand-promoted (DTPA) extractions, used to assess plant-available metal pools, showed decreasing available Zn and Mn with progressive tailings acidification. Aluminum shows the inverse trend, and Pb and Fe show more complex pH dependence. Since the tailings derive from a common source and parent mineralogy, it is presumed that variations in pH and 'bio-available' metal concentrations result from associated variation in particle-scale geochemistry. Four sub-samples, ranging in pH from 2.6 to 5.4, were subjected to further characterization to elucidate micro-scale controls on metal mobility. With acidification, total Pb (ranging from 5 to 13 g kg -1 ) was increasingly associated with Fe and S in plumbojarosite aggregates. For Zn, both total (0.4-6 g kg -1 ) and labile fractions decreased with decreasing pH. Zinc was found to be primarily associated with the secondary Mn phases manjiroite and chalcophanite. The results suggest that progressive tailings acidification diminishes the overall lability of the total Pb and Zn pools.

  6. Energy, Environmental, and Economic Analyses of Design Concepts for the Co-Production of Fuels and Chemicals with Electricity via Co-Gasification of Coal and Biomass

    Energy Technology Data Exchange (ETDEWEB)

    Eric Larson; Robert Williams; Thomas Kreutz; Ilkka Hannula; Andrea Lanzini; Guangjian Liu

    2012-03-11

    The overall objective of this project was to quantify the energy, environmental, and economic performance of industrial facilities that would coproduce electricity and transportation fuels or chemicals from a mixture of coal and biomass via co-gasification in a single pressurized, oxygen-blown, entrained-flow gasifier, with capture and storage of CO{sub 2} (CCS). The work sought to identify plant designs with promising (Nth plant) economics, superior environmental footprints, and the potential to be deployed at scale as a means for simultaneously achieving enhanced energy security and deep reductions in U.S. GHG emissions in the coming decades. Designs included systems using primarily already-commercialized component technologies, which may have the potential for near-term deployment at scale, as well as systems incorporating some advanced technologies at various stages of R&D. All of the coproduction designs have the common attribute of producing some electricity and also of capturing CO{sub 2} for storage. For each of the co-product pairs detailed process mass and energy simulations (using Aspen Plus software) were developed for a set of alternative process configurations, on the basis of which lifecycle greenhouse gas emissions, Nth plant economic performance, and other characteristics were evaluated for each configuration. In developing each set of process configurations, focused attention was given to understanding the influence of biomass input fraction and electricity output fraction. Self-consistent evaluations were also carried out for gasification-based reference systems producing only electricity from coal, including integrated gasification combined cycle (IGCC) and integrated gasification solid-oxide fuel cell (IGFC) systems. The reason biomass is considered as a co-feed with coal in cases when gasoline or olefins are co-produced with electricity is to help reduce lifecycle greenhouse gas (GHG) emissions for these systems. Storing biomass-derived CO

  7. Processing of CuInSe2-Based Solar Cells: Characterization of Deposition Processes in Terms of Chemical Reaction Analyses. Final Report, 6 May 1995 - 31 December 1998

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, T.J.; Stanbery, B.J.

    2001-07-16

    This project describes a novel rotating-disc reactor has been designed and built to enable modulated flux deposition of CuInSe2 and its related binary compounds. The reactor incorporates both a thermally activated source and a novel plasma-activated source of selenium vapor, which have been used for the growth of epitaxial and polycrystalline thin-film layers of CuInSe2. A comparison of the different selenium reactant sources has shown evidence of increases in its incorporation when using the plasma source, but no measurable change when the thermally activated source was used. We concluded that the chemical reactivity of selenium vapor from the plasma source is significantly greater than that provided by the other sources studied. Epitaxially grown CuInSe2 layers on GaAs, ZnTe, and SrF2 demonstrate the importance of nucleation effects on the morphology and crystallographic structure of the resulting materials. These studies have resulted in the first reported growth of the CuAu type-I crystallographic polytype of CuInSe2, and the first reported epitaxial growth of CuInSe2 on ZnTe. Polycrystalline binary (Cu,Se) and (In,Se) thin films have been grown, and the molar flux ratio of selenium to metals was varied. It is shown that all of the reported binary compounds in each of the corresponding binary phase fields can be synthesized by the modulated flux deposition technique implemented in the reactor by controlling this ratio and the substrate temperature. These results were employed to deposit bilayer thin films of specific (Cu,Se) and (In,Se) compounds with low melting-point temperature, which were used to verify the feasibility of synthesizing CuInSe2 by subsequent rapid-thermal processing. The studies of the influence of sodium during the initial stages of epitaxy have led to a new model to explain its influences based on the hypothesis that it behaves as a surfactant in the Cu-In-Se material system. This represents the first unified theory on the role of sodium

  8. Application of information statistical theory to the description of the effect of heat conduction on the chemical reaction rate in gases

    International Nuclear Information System (INIS)

    Fort, J.; Cukrowski, A.S.

    1998-01-01

    The effect of the heat flux on the rate of chemical reaction in dilute gases is shown to be important for reactions characterized by high activation energies and in the presence of very large temperature gradients. This effect, obtained from the second-order terms in the distribution function (similar to those obtained in the Burnett approximation to the solution of the Boltzmann equation), is derived on the basis of information theory. It is shown that the analytical results describing the effect are simpler if the kinetic definition for the nonequilibrium temperature is introduced than if the thermodynamic definition is introduced. The numerical results are nearly the same for both definitions. (author)

  9. Composição físico-química do vinho Cabernet Franc proveniente de videiras conduzidas no sistema lira aberta Physico-chemical composition of Cabernet Franc wine from vineyards conducted in the lyre system

    Directory of Open Access Journals (Sweden)

    Luciano Manfroi

    2006-06-01

    Full Text Available O objetivo do trabalho foi avaliar as características físico-químicas do vinho Cabernet Franc proveniente de videiras conduzidas no sistema lira aberta durante o ciclo vegetativo de 1995/1996. O experimento foi realizado em oito vinhedos localizados nos municípios de Bento Gonçalves e Monte Belo do Sul, Estado do Rio Grande do Sul. Os vinhos foram elaborados por microvinificação, com duas repetições para cada vinhedo, os quais foram analisados por processos físico-químicos, espectrofotometria de absorção atômica e cromatografia líquida e gasosa. Os parâmetros das variáveis mais significativas foram os seguintes: álcool 9,65%, acidez total 69 meq L-1, pH 3,46, extrato seco reduzido 16,0 g L-1, K nas cinzas 49,4%, ácido tartárico 33 meq L-1, glicerol 9,3 g L-1, prolina 669 mg L-1, antocianinas 330 mg L-1, taninos 1,19 g L-1, intensidade de cor 0,286, K 1.078 mg L-1, metanol 101,7 mg L-1 e soma dos álcoois superiores 450 mg L-1. Os resultados dos vinhos avaliados foram relativamente similares aos encontrados em vinhos Cabernet Franc da mesma região elaborados com uvas provenientes de videiras conduzidas em latada. Eles evidenciam que o sistema de condução da videira em lira aberta constitui-se como alternativa para a produção de vinho tinto fino na Serra Gaúcha.The objective of the work was to evaluate the physico-chemical characteristics of the Cabernet Franc wine from the 1995/1996 vegetative cycle. It was conducted in eight vineyards in the communes of Bento Gonçalves and Monte Belo do Sul, State of Rio Grande do Sul, Brazil. From each vineyard, two microvinifications were elaborated and wines were analysed by physicochemical, atomic absorption spetrophotometry, and liquid and gas chromatography processes. The parameters of the most significant variables were the following: alcohol 9.65%, total titratable acidity 69 meq L-1, pH 3.46, reduced dry extract 16.0 g L-1, K in the ashes 49.4%, tartaric acid 33 meq L-1

  10. Steam Electrolysis by Proton-Conducting Solid Oxide Electrolysis Cells (SOECs) with Chemically Stable BaZrO3-Based Electrolytes

    KAUST Repository

    Bi, Lei; Traversa, Enrico

    2015-01-01

    BaZrO3-based material was applied as the electrolyte for proton-conducting solid oxide fuel cells (SOECs). Compared with the instability of BaCeO3-based proton-conductors, BaZrO3-based material could be a more promising candidate for proton

  11. Chemical process hazards analysis

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-02-01

    The Office of Worker Health and Safety (EH-5) under the Assistant Secretary for the Environment, Safety and Health of the US Department (DOE) has published two handbooks for use by DOE contractors managing facilities and processes covered by the Occupational Safety and Health Administration (OSHA) Rule for Process Safety Management of Highly Hazardous Chemicals (29 CFR 1910.119), herein referred to as the PSM Rule. The PSM Rule contains an integrated set of chemical process safety management elements designed to prevent chemical releases that can lead to catastrophic fires, explosions, or toxic exposures. The purpose of the two handbooks, ``Process Safety Management for Highly Hazardous Chemicals`` and ``Chemical Process Hazards Analysis,`` is to facilitate implementation of the provisions of the PSM Rule within the DOE. The purpose of this handbook ``Chemical Process Hazards Analysis,`` is to facilitate, within the DOE, the performance of chemical process hazards analyses (PrHAs) as required under the PSM Rule. It provides basic information for the performance of PrHAs, and should not be considered a complete resource on PrHA methods. Likewise, to determine if a facility is covered by the PSM rule, the reader should refer to the handbook, ``Process Safety Management for Highly Hazardous Chemicals`` (DOE- HDBK-1101-96). Promulgation of the PSM Rule has heightened the awareness of chemical safety management issues within the DOE. This handbook is intended for use by DOE facilities and processes covered by the PSM rule to facilitate contractor implementation of the PrHA element of the PSM Rule. However, contractors whose facilities and processes not covered by the PSM Rule may also use this handbook as a basis for conducting process hazards analyses as part of their good management practices. This handbook explains the minimum requirements for PrHAs outlined in the PSM Rule. Nowhere have requirements been added beyond what is specifically required by the rule.

  12. Effect of annealing temperatures on the electrical conductivity and dielectric properties of Ni1.5Fe1.5O4 spinel ferrite prepared by chemical reaction at different pH values

    Science.gov (United States)

    Aneesh Kumar, K. S.; Bhowmik, R. N.

    2017-12-01

    The electrical conductivity and dielectric properties of Ni1.5Fe1.5O4 ferrite has been controlled by varying the annealing temperature of the chemical routed samples. The frequency activated conductivity obeyed Jonscher’s power law and universal scaling suggested semiconductor nature. An unusual metal like state has been revealed in the measurement temperature scale in between two semiconductor states with different activation energy. The metal like state has been affected by thermal annealing of the material. The analysis of electrical impedance and modulus spectra has confirmed non-Debye dielectric relaxation with contributions from grains and grain boundaries. The dielectric relaxation process is thermally activated in terms of measurement temperature and annealing temperature of the samples. The hole hopping process, due to presence of Ni3+ ions in the present Ni rich ferrite, played a significant role in determining the thermal activated conduction mechanism. This work has successfully applied the technique of a combined variation of annealing temperature and pH value during chemical reaction for tuning electrical parameters in a wide range; for example dc limit of conductivity ~10-4-10-12 S cm-1, and unusually high activation energy ~0.17-1.36 eV.

  13. Coaxial CoMoO4 nanowire arrays with chemically integrated conductive coating for high-performance flexible all-solid-state asymmetric supercapacitors

    Science.gov (United States)

    Chen, Yaping; Liu, Borui; Liu, Qi; Wang, Jun; Li, Zhanshuang; Jing, Xiaoyan; Liu, Lianhe

    2015-09-01

    Flexible all-solid-state supercapacitors have offered promising applications as novel energy storage devices based on their merits, such as small size, low cost, light weight and high wearability for high-performance portable electronics. However, one major challenge to make flexible all-solid-state supercapacitors depends on the improvement of electrode materials with higher electrical conductivity properties and longer cycling stability. In this article, we put forward a simple strategy to in situ synthesize 1D CoMoO4 nanowires (NWs), using highly conductive CC and an electrically conductive PPy wrapping layer on CoMoO4 NW arrays for high performance electrode materials. The results show that the CoMoO4/PPy hybrid NW electrode exhibits a high areal specific capacitance of ca. 1.34 F cm-2 at a current density of 2 mA cm-2, which is remarkably better than the corresponding values for a pure CoMoO4 NW electrode of 0.7 F cm-2. An excellent cycling performance of nanocomposites of up to 95.2% (ca. 1.12 F cm-2) is achieved after 2000 cycles compared to pristine CoMoO4 NWs. In addition, we fabricate flexible all-solid-state ASC which can be cycled reversibly in the voltage range of 0-1.7 V, and exhibits a maximum energy density of 104.7 W h kg-1 (3.522 mW h cm-3), demonstrating great potential for practical applications in flexible energy storage electronics.Flexible all-solid-state supercapacitors have offered promising applications as novel energy storage devices based on their merits, such as small size, low cost, light weight and high wearability for high-performance portable electronics. However, one major challenge to make flexible all-solid-state supercapacitors depends on the improvement of electrode materials with higher electrical conductivity properties and longer cycling stability. In this article, we put forward a simple strategy to in situ synthesize 1D CoMoO4 nanowires (NWs), using highly conductive CC and an electrically conductive PPy wrapping layer on

  14. A comprehensive study of the toxicity of natural multi-contaminated sediments: New insights brought by the use of a combined approach using the medaka embryo-larval assay and physico-chemical analyses.

    Science.gov (United States)

    Barjhoux, Iris; Clérandeau, Christelle; Menach, Karyn Le; Anschutz, Pierre; Gonzalez, Patrice; Budzinski, Hélène; Morin, Bénédicte; Baudrimont, Magalie; Cachot, Jérôme

    2017-08-01

    Sediment compartment is a long term sink for pollutants and a secondary source of contamination for aquatic species. The abiotic factors controlling the bioavailability and thus the toxicity of complex mixtures of pollutants accumulated in sediments are poorly documented. To highlight the different factors influencing sediment toxicity, we identified and analyzed the physico-chemical properties, micro-pollutant contents, and toxicity level of six contrasted sediments in the Lot-Garonne continuum. Sediment toxicity was evaluated using the recently described Japanese medaka (Oryzias latipes) embryo-larval assay with direct exposure to whole sediment (MELAc). Multiple toxicity endpoints including embryotoxicity, developmental defects and DNA damage were analyzed in exposed embryos. Chemical analyses revealed significant variations in the nature and contamination profile of sediments, mainly impacted by metallic trace elements and, unexpectedly, polycyclic aromatic hydrocarbons. Exposure to sediments induced different toxic impacts on medaka early life stages when compared with the reference site. Principal component analysis showed that the toxic responses following exposure to sediments from the Lot River and its tributary were associated with micro-pollutant contamination: biometric measurements, hatching success, genotoxicity, craniofacial deformities and yolk sac malabsorption were specifically correlated to metallic and organic contaminants. Conversely, the main biological responses following exposure to the Garonne River sediments were more likely related to their physico-chemical properties than to their contamination level. Time to hatch, cardiovascular injuries and spinal deformities were correlated to organic matter content, fine particles and dissolved oxygen levels. These results emphasize the necessity of combining physico-chemical analysis of sediment with toxicity assessment to accurately evaluate the environmental risks associated with sediment

  15. Methodology of Supervision by Analysis of Thermal Flux for Thermal Conduction of a Batch Chemical Reactor Equipped with a Monofluid Heating/Cooling System

    Directory of Open Access Journals (Sweden)

    Ghania Henini

    2012-01-01

    Full Text Available We present the thermal behavior of a batch reactor to jacket equipped with a monofluid heating/cooling system. Heating and cooling are provided respectively by an electrical resistance and two plate heat exchangers. The control of the temperature of the reaction is based on the supervision system. This strategy of management of the thermal devices is based on the usage of the thermal flux as manipulated variable. The modulation of the monofluid temperature by acting on the heating power or on the opening degrees of an air-to-open valve that delivers the monofluid to heat exchanger. The study shows that the application of this method for the conduct of the pilot reactor gives good results in simulation and that taking into account the dynamics of the various apparatuses greatly improves ride quality of conduct. In addition thermal control of an exothermic reaction (mononitration shows that the consideration of heat generated in the model representation improve the results by elimination any overshooting of the set-point temperature.

  16. Materials space of solid-state electrolytes: unraveling chemical composition-structure-ionic conductivity relationships in garnet-type metal oxides using cheminformatics virtual screening approaches.

    Science.gov (United States)

    Kireeva, Natalia; Pervov, Vladislav S

    2017-08-09

    The organic electrolytes of most current commercial rechargeable Li-ion batteries (LiBs) are flammable, toxic, and have limited electrochemical energy windows. All-solid-state battery technology promises improved safety, cycling performance, electrochemical stability, and possibility of device miniaturization and enables a number of breakthrough technologies towards the development of new high power and energy density microbatteries for electronics with low processing cost, solid oxide fuel cells, electrochromic devices, etc. Currently, rational materials design is attracting significant attention, which has resulted in a strong demand for methodologies that can accelerate the design of materials with tailored properties; cheminformatics can be considered as an efficient tool in this respect. This study was focused on several aspects: (i) identification of the parameters responsible for high Li-ion conductivity in garnet structured oxides; (ii) development of quantitative models to elucidate composition-structure-Li ionic conductivity relationships, taking into account the experimental details of sample preparation; (iii) circumscription of the materials space of solid garnet-type electrolytes, which is attractive for virtual screening. Several candidate compounds have been recommended for synthesis as potential solid state electrolyte materials.

  17. Conducting Polymers

    Indian Academy of Sciences (India)

    would exhibit electronic conductivity, their conductivities (of compressed pellets) were indeed measured by others, and were found to be .... Polyaniline. Polyphenylene. Polypheny lene- vinylene. Table 1. G!NeRAl I ARTICl! structure. Maximum conductivity Stem Stability. Processability. ~. 1.5 x 105. Reacts with Film not n air.

  18. Capacitance–voltage and current–voltage characteristics for the study of high background doping and conduction mechanisms in GaAsN grown by chemical beam epitaxy

    International Nuclear Information System (INIS)

    Bouzazi, Boussairi; Kojima, Nobuaki; Ohshita, Yoshio; Yamaguchi, Masafumi

    2013-01-01

    Highlights: ► The cause of high background doping was confirmed and characterized. ► The current–voltage characteristics deviate from the thermionic emission. ► The recombination current is attributed to a hole trap (E V + 0.52 eV). ► The hole trap (E V + 0.52 eV) was confirmed by DLTS measurements. -- Abstract: The temperature dependence of capacitance–voltage (C–V) and current voltage (I–V) characteristics were used to study the cause of high background doping and the underlying current transport mechanisms in GaAsN Schottky diode grown by chemical beam epitaxy (CBE). In one hand, a nitrogen-related sigmoid increase of junction capacitance and ionized acceptor concentration was observed in the temperature range 70–100 K and was attributed to the thermal ionization of a nitrogen–hydrogen-related deep acceptor-state, with thermal activation energy of approximately 0.11 eV above the valence band maximum (VBM) of GaAsN. This acceptor state is mainly responsible for the high background doping in unintentionally doped GaAsN grown by CBE. On the other hand, the I–V characteristics at different temperatures were found to deviate from the well known pure thermionic-emission mechanism. Based on their fitting at each temperature, the recombination current in the space charge region of GaAsN Schottky diode was mainly attributed to a hole trap, localized at 0.51 eV above the VBM. Given the accuracy of measurements, this result was confirmed by deep level transient spectroscopy measurements. Nevertheless, considering the Shockley–Read–Hall model of generation-recombination, the recombination activity of this defect was quantified and qualified to be weak compared with the markedly degradation of minority carrier lifetime in GaAsN material

  19. Post-irradiation chemical analyses of poultry

    International Nuclear Information System (INIS)

    Singh, H.

    1988-01-01

    Salmonella contamination of chicken is a major public health concern, causing sickness and loss of productivity. Modern concentrated production methods increase the difficulty of Salmonella control. While heat pasteurization and chlorine treatment for Salmonella have shortcomings, low doses of gamma radiation are very effective in controlling Salmonella and spoilage microorganisms. The organoleptic shelf life of fresh chicken at 1 to 4 degrees Celsius (6 to 10 days) is extended by a factor of ∼ 2 by a dose of 2.5 kGy and does not increase further with higher doses up to ∼ 8 kGy. The reason for the lack of greater organoleptic shelf life by more than a factor of ∼ 2 is the continuing degradative changes in meat due to enzymatic activity. The product obtained with doses around 2.5 kGy is very good, and is acceptable up to doses of ∼ 8 kGy. Irradiation at doses higher than 2.5 kGy results in some radiation odor that disappears on storage at 1 to 4 degrees Celsius, and on roasting of the meat. The odor is due to the production of some of the small molecular weight volatile compounds, which are also produced by free-radical mediated autoxidation, thermal treatment, and enzymatic and microbial reactions with the meat components. Low-dose irradiation shows insignificant changes in the physical attributes like water-holding capacity, changes in proteins, amino acids, fats and rancidity indices. Review of the feeding studies with radiation-sterilized chicken meat (≥ 30 kGy, the Raltech study) indicated that the irradiated meat was wholesome and safe. It is therefore, reasonable to assume that the low-dose (≤ 8 kGy) irradiated chicken would also be safe. Also the two Federation of American Societies for Experimental Biology (FASEB) committees, which reviewed the over 100 identified volatile compounds produced in μg/kg (ppb) quantities, concluded that there were no ground for suspecting these products of being a hazard to the consumer

  20. Chemical analyses, antibacterial activity and genetic diversity ...

    African Journals Online (AJOL)

    The phylogenetic tree separated the varieties into discrete clusters according to their respective citrus group. Citrus groups were initially divided into two main clusters at 0.18 level of similarity. Lemon, lime, mandarin and sour orange were grouped in the first cluster, while sweet orange, grapefruit and pummelo were nested ...

  1. Chemical analyses, antibacterial activity and genetic diversity ...

    African Journals Online (AJOL)

    SAM

    2014-06-25

    Jun 25, 2014 ... orange were grouped in the first cluster, while sweet orange, grapefruit and pummelo were nested in the second cluster. ... This information can provide ...... Rekha C, Poornima G, Manasa M, Abhipsa V, Pavithra Devi J, Vijay.

  2. Results of Toxicity Studies Conducted on Outfall X-08 and Its Contributing Waste Streams, November 1999 - June 2000

    International Nuclear Information System (INIS)

    Specht, W.L.

    2000-01-01

    This interim report summarizes the results of toxicity tests, Toxicity Identification Evaluations, and chemical analyses that have been conducted on SRS's NPDES Outfall X-08 and its contributing waste streams between November 1999 and June 2000

  3. Measurement of unsaturated hydraulic conductivity and chemical transport in Yucca Mountain Tuff: Milestone Report 3044-WBS1.2.3.4.1.4.1

    International Nuclear Information System (INIS)

    Conca, J.L.

    1993-12-01

    Hydraulic conductivities, K, were experimentally determined as a function of volumetric water content, θ, in tuff from the Yucca Mountain site. In addition, the retardation factor, R f , in Yucca Mountain tuff with respect to selenium, as the selenite species, was measured under unsaturated conditions. These data were used to determine the feasibility of applying a new unsaturated flow technology (UFA) to further hydrologic studies at Yucca Mountain. The UFA directly measures K(θ) rapidly in Yucca Mountain tuff and is shown to agree well with traditional methods. Hysteresis does not appear important during this testing. Hydraulic steady-state is achieved fastest during desaturation from a saturated state. Imbibition into dry tuff requires a long time for steady-state to occur because of slow filling of the diffusion porosity which can take a few weeks. The existing UFA is a prototype, and a new design of the next generation UFA is completed that eliminates some of the earlier problems. These preliminary investigations demonstrates that the UFA is a useful investigate technique that should be used to compliment existing techniques for hydrogeochemical characterization at Yucca Mountain and other arid sites

  4. The role of transparent conducting oxides in metal organic chemical vapour deposition of CdTe/CdS Photovoltaic solar cells

    International Nuclear Information System (INIS)

    Irvine, S.J.C.; Lamb, D.A.; Barrioz, V.; Clayton, A.J.; Brooks, W.S.M.; Rugen-Hankey, S.; Kartopu, G.

    2011-01-01

    A systematic study is made between the relationship of Cd 0.9 Zn 0.1 S/CdTe photovoltaic (PV) device properties for three different commercial transparent conducting oxide (TCO) materials and some experimental CdO to determine the role of the TCO in device performance. The resistance contribution from the TCO was measured after depositing the gold contact architectures directly onto the TCOs. These were compared with the Cd 0.9 Zn 0.1 S/CdTe device properties using the same contact arrangements. Series resistance for the commercial TCOs correlated with their sheet resistance and gave good agreement with the PV device series resistance for the indium tin oxide (ITO) and fluorine doped tin oxide (FTO) 15 Ω/Sq. superstrates. The devices on the thicker FTO 7 Ω/sq superstrates were dominated by a low shunt resistance, which was attributed to the rough surface morphology causing micro-shorts. The device layers on the CdO substrate delaminated but devices were successfully made for ultra-thin CdTe (0.8 μm thick) and compared favourably with the comparable device on ITO. From the measurements on these TCOs it was possible to deduce the back contact resistance and gave an average value of 2 Ω.cm 2 . The correlation of fill factor with series resistance has been compared with the predictions of a 1-D device model and shows excellent agreement. For high efficiency devices the combined series resistance from the TCO and back contact need to be less than 1 Ω.cm 2 .

  5. Uranium favorability of tertiary sedimentary rocks of the Pend Oreille River valley, Washington. [Measurement and sampling of surface sections, collection of samples from isolated outcrops, chemical and mineralogical analyses of samples, and examination of available water logs

    Energy Technology Data Exchange (ETDEWEB)

    Marjaniemi, D.K.; Robins, J.W.

    1975-08-01

    Tertiary sedimentary rocks in the Pend Oreille River valley were investigated in a regional study to determine the favorability for potential uranium resources of northeastern Washington. This project involved measurement and sampling of surface sections, collection of samples from isolated outcrops, chemical and mineralogical analyses of samples, and examination of available water well logs. The Box Canyon Dam area north of Ione is judged to have very high favorability. Thick-bedded conglomerates interbedded with sandstones and silty sandstones compose the Tiger Formation in this area, and high radioactivity levels are found near the base of the formation. Uranophane is found along fracture surfaces or in veins. Carbonaceous material is present throughout the Tiger Formation in the area. Part of the broad Pend Oreille valley surrounding Cusick, Washington, is an area of high favorability. Potential host rocks in the Tiger Formation, consisting of arkosic sandstones interbedded with radioactive shales, probably extend throughout the subsurface part of this area. Carbonaceous material is present and some samples contain high concentrations of uranium. In addition, several other possible chemical indicators were found. The Tiger-Lost Creek area is rated as having medium favorability. The Tiger Formation contains very hard, poorly sorted granite conglomerate with some beds of arkosic sandstone and silty sandstone. The granite conglomerate was apparently derived from source rocks having relatively high uranium content. The lower part of the formation is more favorable than the upper part because of the presence of carbonaceous material, anomalously high concentrations of uranium, and other possible chemical indicators. The area west of Ione is judged to have low favorability, because of the very low permeability of the rocks and the very low uranium content. (auth)

  6. Graphene Conductance Uniformity Mapping

    DEFF Research Database (Denmark)

    Buron, Jonas Christian Due; Petersen, Dirch Hjorth; Bøggild, Peter

    2012-01-01

    We demonstrate a combination of micro four-point probe (M4PP) and non-contact terahertz time-domain spectroscopy (THz-TDS) measurements for centimeter scale quantitative mapping of the sheet conductance of large area chemical vapor deposited graphene films. Dual configuration M4PP measurements......, demonstrated on graphene for the first time, provide valuable statistical insight into the influence of microscale defects on the conductance, while THz-TDS has potential as a fast, non-contact metrology method for mapping of the spatially averaged nanoscopic conductance on wafer-scale graphene with scan times......, dominating the microscale conductance of the investigated graphene film....

  7. Conducting metal dithiolate complexes

    DEFF Research Database (Denmark)

    Underhill, A. E.; Ahmad, M. M.; Turner, D. J.

    1985-01-01

    Further work on the chemical composition of the one-dimensional metallic metal dithiolene complex Li-Pt(mnt) is reported. The electrical conduction and thermopower properties of the nickel and palladium complexes are reported and compared with those of the platinum compound......Further work on the chemical composition of the one-dimensional metallic metal dithiolene complex Li-Pt(mnt) is reported. The electrical conduction and thermopower properties of the nickel and palladium complexes are reported and compared with those of the platinum compound...

  8. Heat conduction

    International Nuclear Information System (INIS)

    Grigull, U.; Sandner, H.

    1984-01-01

    Included are discussions of rates of heat transfer by conduction, the effects of varying and changing properties, thermal explosions, distributed heat sources, moving heat sources, and non-steady three-dimensional conduction processes. Throughout, the importance of thinking both numerically and symbolically is stressed, as this is essential to the development of the intuitive understanding of numerical values needed for successful designing. Extensive tables of thermophysical properties, including thermal conductivity and diffusivity, are presented. Also included are exact and approximate solutions to many of the problems that arise in practical situations

  9. Electrical Conductivity.

    Science.gov (United States)

    Hershey, David R.; Sand, Susan

    1993-01-01

    Explains how electrical conductivity (EC) can be used to measure ion concentration in solutions. Describes instrumentation for the measurement, temperature dependence and EC, and the EC of common substances. (PR)

  10. Conduct Disorder

    Science.gov (United States)

    ... objections runs away from home often truant from school Children who exhibit these behaviors should receive a comprehensive evaluation by an experience mental health professional. Many children with a conduct disorder may ...

  11. ANÁLISIS QUÍMICO Y DE ALMIDONES EN LA DETERMINACIÓN DE USOS DE TINAJAS ARQUEOLÓGICAS EN EL SITIO GUACHIMONTONES (MÉXICO (Starch and Chemical Analyses in Determining Uses of Archaeological Jars from the Guachimontones Site, Mexico

    Directory of Open Access Journals (Sweden)

    Miguel Ángel Novillo Verdugo

    2016-03-01

    Full Text Available La cerámica, por sus características constitutivas, es resistente al paso del tiempo y, por ende, es un recurso propicio para la generación de datos que permiten conocer el uso que desempeñaban los objetos arqueológicos. Así, se analizó un conjunto cerámico correspondiente a ocho tinajas registradas en el sitio arqueológico Guachimontones, por medio de análisis químicos y de almidones. Las pruebas aplicadas estuvieron enfocadas a reconocer residuos orgánicos e inorgánicos. Dichos análisis, que se realizaron en la cerámica, se complementan, pues la química representa una aproximación al uso particular de un artefacto, mientras que los almidones corroboraron dicho uso en prácticas alimentarias, medicinales o ceremoniales. ENGLISH: Ceramics, by their constituent features, are resistant to degradation over time and thus are suitable for generating data that provide insight into their use. Thus, chemical and starch analyses were conducted on a set of eight ceramic jars registered at the archaeological site of Guachimontones. The tests applied were chosen in order to identify evidence of organic and inorganic waste. These analyses are complimentary because chemistry indicates the particular use of an artifact while starches corroborate their use in such things as food, medicinal, or ceremonial practices.

  12. Theoretical study of the electronic structure of f-element complexes by quantum chemical methods; Analyse de la structure electronique des complexes contenant des elements F par des methodes de la chimie quantique

    Energy Technology Data Exchange (ETDEWEB)

    Vetere, V

    2002-09-15

    This thesis is related to comparative studies of the chemical properties of molecular complexes containing lanthanide or actinide trivalent cations, in the context of the nuclear waste disposal. More precisely, our aim was a quantum chemical analysis of the metal-ligand bonding in such species. Various theoretical approaches were compared, for the inclusion of correlation (density functional theory, multiconfigurational methods) and of relativistic effects (relativistic scalar and 2-component Hamiltonians, relativistic pseudopotentials). The performance of these methods were checked by comparing computed structural properties to published experimental data, on small model systems: lanthanide and actinide tri-halides and on X{sub 3}M-L species (X=F, Cl; M=La, Nd, U; L = NH{sub 3}, acetonitrile, CO). We have thus shown the good performance of density functionals combined with a quasi-relativistic method, as well as of gradient-corrected functionals associated with relativistic pseudopotentials. In contrast, functionals including some part of exact exchange are less reliable to reproduce experimental trends, and we have given a possible explanation for this result . Then, a detailed analysis of the bonding has allowed us to interpret the discrepancies observed in the structural properties of uranium and lanthanides complexes, based on a covalent contribution to the bonding, in the case of uranium(III), which does not exist in the lanthanide(III) homologues. Finally, we have examined more sizeable systems, closer to experimental species, to analyse the influence of the coordination number, of the counter-ions and of the oxidation state of uranium, on the metal-ligand bonding. (author)

  13. Lunar Science Conference, 4th, Houston, Tex., March 5-8, 1973, 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.

    1973-01-01

    The mineralogy, petrology, chemistry, isotopic composition, and physical properties of lunar materials are described in papers detailing methods, results, and implications of research on samples returned from eight lunar landing sites: Apollo 11, 12, 14, 15, 16, 17, and Luna 16 and 20. The results of experiments conducted or set up on the lunar surface by the astronauts are also described along with observations taken from Command Modules and subsatellites. Major topics include general geology, soil and breccia studies, petrologic studies, mineralogic analyses, elemental compositions, radiometric age determinations, rare gas chemistry, radionuclides, organogenic compounds, particle track records, thermal properties, seismic studies, resonance studies, orbital mapping, lunar atmosphere, magnetic studies, electrical studies, optical properties, and microcratering. Individual items are announced in this issue.

  14. Conduct disorders

    NARCIS (Netherlands)

    Buitelaar, J.K.; Smeets, K.C.; Herpers, P.; Scheepers, F.; Glennon, J.; Rommelse, N.N.J.

    2013-01-01

    Conduct disorder (CD) is a frequently occurring psychiatric disorder characterized by a persistent pattern of aggressive and non-aggressive rule breaking antisocial behaviours that lead to considerable burden for the patients themselves, their family and society. This review paper updates diagnostic

  15. Ionic/Electronic Conductivity, Thermal/Chemical Expansion and Oxygen Permeation in Pr and Gd Co-Doped Ceria PrxGd0.1Ce0.9-xO1.95-δ

    DEFF Research Database (Denmark)

    Cheng, Shiyang; Chatzichristodoulou, Christodoulos; Søgaard, Martin

    2017-01-01

    Pr. A series of compositions of PrxGd0.1Ce0.9-xO1.95-δ (x = 0, 0.02, 0.05, 0.08, 0.15, 0.25, 0.3 and 0.4) was prepared by solid state reaction. X-ray powder diffraction (XPD) indicates that Pr is completely dissolved in the fluorite structure up to 40 at.%. Pronounced nonlinear thermal expansion...... behavior was observed as a function of temperature, due to the simultaneous contributions of both thermal and chemical expansion. The electronic and ionic conductivities were measured as a function of temperature and oxygen partial pressure. Within the range from 10 to 15 at.% Pr, a drastic drop...

  16. Avaliação das propriedades físicas, químicas e sensorial de preferência de goiabas em calda industrializadas Physical, chemical and sensorial analyses of industrialized guava in syrup

    Directory of Open Access Journals (Sweden)

    A. C. K. Sato

    2004-12-01

    Full Text Available Quatro marcas de goiabas em calda foram submetidas a análises físico-químicas, de cor e textura instrumentais e teste sensorial de preferência, a fim de avaliar as diferenças entre os produtos comerciais. As mesmas análises foram efetuadas em uma goiaba in natura madura, a fim de avaliar os possíveis efeitos do processamento na qualidade do produto. De maneira geral, observou-se grandes diferenças entre os produtos das diferentes marcas, e muitas vezes entre os frutos de um mesmo fabricante. As análises químicas mostraram que o teor de açúcares da maior parte dos produtos está entre 22 e 30%, com exceção de uma amostra que mostrou um valor bem mais elevado (ao redor de 40%. A análise sensorial mostrou que esta amostra com maior teor de açúcares foi a mais preferida em relação à doçura. Na análise de cor foram observados menores valores de a* em relação à fruta in natura, possivelmente devido à degradação dos carotenóides da goiaba. A luminosidade das goiabas em calda também é maior que da fruta in natura, devido à presença dos açúcares. Esta entrada de açúcares na fruta junto com o processamento térmico utilizado pode ter causado possível gelificação da pectina, aumentando a dureza, firmeza e elasticidade de algumas amostras processadas, quando comparadas à fruta fresca. No entanto, em alguns casos foi visível o efeito de processamentos mais drásticos, que levaram à perda da estrutura celular, observada pelos baixos valores das propriedades mecânicas. Em relação à textura e aparência, a amostra mais dura foi a preferida.Four brands of canned guava were submitted to physico-chemical, sensory (preference test and instrumental color and texture analyses, in order to evaluate the differences between commercial products. The same analyses were made on a fresh, mature guava, to evaluate possible effects of processing on the quality of the final product. There were considerable differences between the

  17. Lessons learned from radioactive/mixed waste analyses at EG ampersand G Idaho, Inc

    International Nuclear Information System (INIS)

    Murphy, R.J.; Sailer, S.J.; Bennett, J.T.; Arvizu, J.S.

    1990-01-01

    For the past 30 years extensive chemical characterizations of environmental and waste samples have been performed by numerous academic, commercial, and government analytical chemistry laboratories for the purposes of research, monitoring, and compliance with regulations. The vast majority of these analyses, however, has been conducted on samples containing natural concentrations of radioactive constituents. It is only within the last decade that a small number of laboratories have been conducting extensive chemical characterizations of highly radioactive samples and consequently have begun to identify many special requirements for the safe and accurate conduct of such analyses. Experience gained from chemical analyses of radioactively contaminated samples has indicated special requirements and actions needed in the following three general areas: Sample collection and preservation; chemical analysis protocols; disposal of waste from chemical analyses. In this paper we will summarize the experience and findings acquired from four years of radioactive sample analyses by the Environmental Chemistry Unit, an analytical chemistry laboratory of EG ampersand G Idaho, Inc. at the Idaho National Engineering Laboratory. 6 tabs

  18. Conductivity Probe

    Science.gov (United States)

    2008-01-01

    The Thermal and Electrical Conductivity Probe (TECP) for NASA's Phoenix Mars Lander took measurements in Martian soil and in the air. The needles on the end of the instrument were inserted into the Martian soil, allowing TECP to measure the propagation of both thermal and electrical energy. TECP also measured the humidity in the surrounding air. The needles on the probe are 15 millimeters (0.6 inch) long. The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

  19. Conduct disorders.

    Science.gov (United States)

    Buitelaar, Jan K; Smeets, Kirsten C; Herpers, Pierre; Scheepers, Floor; Glennon, Jeffrey; Rommelse, Nanda N J

    2013-02-01

    Conduct disorder (CD) is a frequently occurring psychiatric disorder characterized by a persistent pattern of aggressive and non-aggressive rule breaking antisocial behaviours that lead to considerable burden for the patients themselves, their family and society. This review paper updates diagnostic and therapeutic approaches to CD in the light of the forthcoming DSM-5 definition. The diagnostic criteria for CD will remain unchanged in DSM-5, but the introduction of a specifier of CD with a callous-unemotional (CU) presentation is new. Linked to this, we discuss the pros and cons of various other ways to subtype aggression/CD symptoms. Existing guidelines for CD are, with few exceptions, already of a relatively older date and emphasize that clinical assessment should be systematic and comprehensive and based on a multi-informant approach. Non-medical psychosocial interventions are recommended as the first option for the treatment of CD. There is a role for medication in the treatment of comorbid syndromes and/or in case of insufficient response to psychosocial interventions and severe and dangerous aggressive and violent behaviours.

  20. Multicollinearity in Regression Analyses Conducted in Epidemiologic Studies.

    Science.gov (United States)

    Vatcheva, Kristina P; Lee, MinJae; McCormick, Joseph B; Rahbar, Mohammad H

    2016-04-01

    The adverse impact of ignoring multicollinearity on findings and data interpretation in regression analysis is very well documented in the statistical literature. The failure to identify and report multicollinearity could result in misleading interpretations of the results. A review of epidemiological literature in PubMed from January 2004 to December 2013, illustrated the need for a greater attention to identifying and minimizing the effect of multicollinearity in analysis of data from epidemiologic studies. We used simulated datasets and real life data from the Cameron County Hispanic Cohort to demonstrate the adverse effects of multicollinearity in the regression analysis and encourage researchers to consider the diagnostic for multicollinearity as one of the steps in regression analysis.

  1. Multicollinearity in Regression Analyses Conducted in Epidemiologic Studies

    OpenAIRE

    Vatcheva, Kristina P.; Lee, MinJae; McCormick, Joseph B.; Rahbar, Mohammad H.

    2016-01-01

    The adverse impact of ignoring multicollinearity on findings and data interpretation in regression analysis is very well documented in the statistical literature. The failure to identify and report multicollinearity could result in misleading interpretations of the results. A review of epidemiological literature in PubMed from January 2004 to December 2013, illustrated the need for a greater attention to identifying and minimizing the effect of multicollinearity in analysis of data from epide...

  2. Direct Observation in the Conduct of Training Impact Analyses

    Science.gov (United States)

    2000-04-01

    with the point of the pen barely extruding from the wrapper (the tight fit keeps both the pen and chemlight in place). This will put a spot of soft...recommendations for supplying that office: A-2 Snack food and beverages (your next opportunity for a meal may not be predictable) Ample supply of notepads

  3. Analysis of determination modalities concerning the exposure and emission limits values of chemical and radioactive substances; Analyse des modalites de fixation des valeurs limites d'exposition et d'emission pour les substances chimiques et radioactives

    Energy Technology Data Exchange (ETDEWEB)

    Schieber, C.; Schneider, T

    2002-08-01

    This document presents the generic approach adopted by various organizations for the determination of the public exposure limits values to chemical and radioactive substances and for the determination of limits values of chemical products emissions by some installations. (A.L.B.)

  4. Conducting polymer 3D microelectrodes

    DEFF Research Database (Denmark)

    Sasso, Luigi; Vazquez, Patricia; Vedarethinam, Indumathi

    2010-01-01

    Conducting polymer 3D microelectrodes have been fabricated for possible future neurological applications. A combination of micro-fabrication techniques and chemical polymerization methods has been used to create pillar electrodes in polyaniline and polypyrrole. The thin polymer films obtained...... showed uniformity and good adhesion to both horizontal and vertical surfaces. Electrodes in combination with metal/conducting polymer materials have been characterized by cyclic voltammetry and the presence of the conducting polymer film has shown to increase the electrochemical activity when compared...

  5. Transparent conducting oxide nanotubes

    Science.gov (United States)

    Alivov, Yahya; Singh, Vivek; Ding, Yuchen; Nagpal, Prashant

    2014-09-01

    Thin film or porous membranes made of hollow, transparent, conducting oxide (TCO) nanotubes, with high chemical stability, functionalized surfaces and large surface areas, can provide an excellent platform for a wide variety of nanostructured photovoltaic, photodetector, photoelectrochemical and photocatalytic devices. While large-bandgap oxide semiconductors offer transparency for incident light (below their nominal bandgap), their low carrier concentration and poor conductivity makes them unsuitable for charge conduction. Moreover, materials with high conductivity have nominally low bandgaps and hence poor light transmittance. Here, we demonstrate thin films and membranes made from TiO2 nanotubes heavily-doped with shallow Niobium (Nb) donors (up to 10%, without phase segregation), using a modified electrochemical anodization process, to fabricate transparent conducting hollow nanotubes. Temperature dependent current-voltage characteristics revealed that TiO2 TCO nanotubes, doped with 10% Nb, show metal-like behavior with resistivity decreasing from 6.5 × 10-4 Ωcm at T = 300 K (compared to 6.5 × 10-1 Ωcm for nominally undoped nanotubes) to 2.2 × 10-4 Ωcm at T = 20 K. Optical properties, studied by reflectance measurements, showed light transmittance up to 90%, within wavelength range 400 nm-1000 nm. Nb doping also improves the field emission properties of TCO nanotubes demonstrating an order of magnitude increase in field-emitter current, compared to undoped samples.

  6. Conducting Polymer Based Nanobiosensors

    Directory of Open Access Journals (Sweden)

    Chul Soon Park

    2016-06-01

    Full Text Available In recent years, conducting polymer (CP nanomaterials have been used in a variety of fields, such as in energy, environmental, and biomedical applications, owing to their outstanding chemical and physical properties compared to conventional metal materials. In particular, nanobiosensors based on CP nanomaterials exhibit excellent performance sensing target molecules. The performance of CP nanobiosensors varies based on their size, shape, conductivity, and morphology, among other characteristics. Therefore, in this review, we provide an overview of the techniques commonly used to fabricate novel CP nanomaterials and their biosensor applications, including aptasensors, field-effect transistor (FET biosensors, human sense mimicking biosensors, and immunoassays. We also discuss prospects for state-of-the-art nanobiosensors using CP nanomaterials by focusing on strategies to overcome the current limitations.

  7. A simple beam analyser

    International Nuclear Information System (INIS)

    Lemarchand, G.

    1977-01-01

    (ee'p) experiments allow to measure the missing energy distribution as well as the momentum distribution of the extracted proton in the nucleus versus the missing energy. Such experiments are presently conducted on SACLAY's A.L.S. 300 Linac. Electrons and protons are respectively analysed by two spectrometers and detected in their focal planes. Counting rates are usually low and include time coincidences and accidentals. Signal-to-noise ratio is dependent on the physics of the experiment and the resolution of the coincidence, therefore it is mandatory to get a beam current distribution as flat as possible. Using new technologies has allowed to monitor in real time the behavior of the beam pulse and determine when the duty cycle can be considered as being good with respect to a numerical basis

  8. Processing of CuInSe{sub 2}-based solar cells: Characterization of deposition processes in terms of chemical reaction analyses. Phase 2 Annual Report, 6 May 1996--5 May 1997

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, T.

    1999-10-20

    This report describes research performed by the University of Florida during Phase 2 of this subcontract. First, to study CIGS, researchers adapted a contactless, nondestructive technique previously developed for measuring photogenerated excess carrier lifetimes in SOI wafers. This dual-beam optical modulation (DBOM) technique was used to investigate the differences between three alternative methods of depositing CdS (conventional chemical-bath deposition [CBD], metal-organic chemical vapor deposition [MOCVD], and sputtering). Second, a critical assessment of the Cu-In-Se thermochemical and phase diagram data using standard CALPHAD procedures is being performed. The outcome of this research will produce useful information on equilibrium vapor compositions (required annealing ambients, Sex fluxes from effusion cells), phase diagrams (conditions for melt-assisted growth), chemical potentials (driving forces for diffusion and chemical reactions), and consistent solution models (extents of solid solutions and extending phase diagrams). Third, an integrated facility to fabricate CIS PV devices was established that includes migration-enhanced epitaxy (MEE) for deposition of CIS, a rapid thermal processing furnace for absorber film formation, sputtering of ZnO, CBD or MOCVD of CdS, metallization, and pattern definition.

  9. Chemical Dependence and Personality

    Directory of Open Access Journals (Sweden)

    Carlos Henrique Sancineto da Silva Nunes

    2009-01-01

    Full Text Available This study investigated the relationships between chemical dependency and personalitystructure in a Brazilian sample. Participants were college students (n=35 and patients of a drug recovery center (n= 48. Two personality scales based on the Big-5 Model were used to measure Extraversion and Agreeableness. A semi-structured interview was used to identify events in the patients' life histories that might support specific classifications. Participants' scores were also compared to Brazilian normative samples. The results showed significant differences between clinical and non-clinical groups in Agreeableness, but not in Extraversion. Logistic regression analyses were conducted using scales and interview aspects for predicting group membership. The model showed 92.1% general predictive power. Results pointed to the advantage of using both interview and objective techniques to assess individuals with antisocial personality symptoms.

  10. Chemical Peels

    Science.gov (United States)

    ... care Kids’ zone Video library Find a dermatologist Chemical peels Overview Chemical peels: Overview Also called chemexfoliation , derma peeling Do ... Overview Chemical peels: FAQs Chemical peels: Preparation FAQs Chemical peels: FAQs To help you decide whether this ...

  11. Islamic State and Chemical Weapons

    Directory of Open Access Journals (Sweden)

    Lukáš Rafay

    2016-09-01

    Full Text Available The article deals with topic of Islamic State and chemical weapons. The issue is analysed in three dimensions: origin of used chemical weapons and possibility of independent production; known chemical attacks and tactical regularities in their execution; and traits of future chemical terrorist attacks. By providing a thorough examination of the problem, the article aims at predicting the future development of the group’s chemical program as well as describing any prospective chemical terrorist attacks in Europe

  12. Physico-chemical characteristics and Heavy metal levels in Drinking ...

    African Journals Online (AJOL)

    Michael Horsfall

    ABSTRAC: This study investigated the physico-chemical characteristics of drinking waters collected from tap, well and sachet in Sokoto metropolis in North Western Nigeria. Conductivity and pH values were determined by standard methods while elemental composition was analysed using X-ray Fluorescence spectroscopy ...

  13. LCA of Chemicals and Chemical Products

    DEFF Research Database (Denmark)

    Fantke, Peter; Ernstoff, Alexi

    2018-01-01

    This chapter focuses on the application of Life Cycle Assessment (LCA) to evaluate the environmental performance of chemicals as well as of products and processes where chemicals play a key role. The life cycle stages of chemical products, such as pharmaceuticals drugs or plant protection products......, are discussed and differentiated into extraction of abiotic and biotic raw materials, chemical synthesis and processing, material processing, product manufacturing, professional or consumer product use, and finally end-of-life . LCA is discussed in relation to other chemicals management frameworks and concepts...... including risk assessment , green and sustainable chemistry , and chemical alternatives assessment. A large number of LCA studies focus on contrasting different feedstocks or chemical synthesis processes, thereby often conducting a cradle to (factory) gate assessment. While typically a large share...

  14. 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 ...

  15. Records of wells and chemical analyses of water from wells for the period June 13, 1984 to December 4, 1986 at the Maxey Flats Radioactive Waste Disposal Site, Kentucky

    Science.gov (United States)

    Lyverse, M.A.

    1987-01-01

    Lithologic data are presented for 113 wells drilled at the Maxey Flats Radioactive Waste Disposal Site for the period June 13, 1984 to December 4, 1986. Water levels, tritium concentrations, and specific conductance are also presented for wells yielding sufficient water for measuring and sampling. At least one sample was collected from most wells for the determination of gross alpha and beta activity. These activities and the results for gamma emitting radionuclides (Cobalt 60 and Cesium 137) are also presented. (USGS)

  16. Capacitive chemical sensor

    Science.gov (United States)

    Manginell, Ronald P; Moorman, Matthew W; Wheeler, David R

    2014-05-27

    A microfabricated capacitive chemical sensor can be used as an autonomous chemical sensor or as an analyte-sensitive chemical preconcentrator in a larger microanalytical system. The capacitive chemical sensor detects changes in sensing film dielectric properties, such as the dielectric constant, conductivity, or dimensionality. These changes result from the interaction of a target analyte with the sensing film. This capability provides a low-power, self-heating chemical sensor suitable for remote and unattended sensing applications. The capacitive chemical sensor also enables a smart, analyte-sensitive chemical preconcentrator. After sorption of the sample by the sensing film, the film can be rapidly heated to release the sample for further analysis. Therefore, the capacitive chemical sensor can optimize the sample collection time prior to release to enable the rapid and accurate analysis of analytes by a microanalytical system.

  17. Correlated Raman micro-spectroscopy and scanning electron microscopy analyses of flame retardants in environmental samples: a micro-analytical tool for probing chemical composition, origin and spatial distribution.

    Science.gov (United States)

    Ghosal, Sutapa; Wagner, Jeff

    2013-07-07

    We present correlated application of two micro-analytical techniques: scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM/EDS) and Raman micro-spectroscopy (RMS) for the non-invasive characterization and molecular identification of flame retardants (FRs) in environmental dusts and consumer products. The SEM/EDS-RMS technique offers correlated, morphological, molecular, spatial distribution and semi-quantitative elemental concentration information at the individual particle level with micrometer spatial resolution and minimal sample preparation. The presented methodology uses SEM/EDS analyses for rapid detection of particles containing FR specific elements as potential indicators of FR presence in a sample followed by correlated RMS analyses of the same particles for characterization of the FR sub-regions and surrounding matrices. The spatially resolved characterization enabled by this approach provides insights into the distributional heterogeneity as well as potential transfer and exposure mechanisms for FRs in the environment that is typically not available through traditional FR analysis. We have used this methodology to reveal a heterogeneous distribution of highly concentrated deca-BDE particles in environmental dust, sometimes in association with identifiable consumer materials. The observed coexistence of deca-BDE with consumer material in dust is strongly indicative of its release into the environment via weathering/abrasion of consumer products. Ingestion of such enriched FR particles in dust represents a potential for instantaneous exposure to high FR concentrations. Therefore, correlated SEM/RMS analysis offers a novel investigative tool for addressing an area of important environmental concern.

  18. Comparison of Gas Chromatography-Mass Spectrometry and Gas Chromatography-Tandem Mass Spectrometry with Electron Ionization and Negative-Ion Chemical Ionization for Analyses of Pesticides at Trace Levels in Atmospheric Samples

    Directory of Open Access Journals (Sweden)

    Renata Raina

    2008-01-01

    Full Text Available A comparison of detection limits of gas chromatography-mass spectrometry (GC-MS in selected ion monitoring (SIM with gas chromatography-tandem mass spectrometry (GC-MS/MS in selected reaction monitoring (SRM mode with both electron ionization (EI and negative-ion chemical ionization (NCI are presented for over 50 pesticides ranging from organochlorines (OCs, organophosphorus pesticides (OPs and pre-emergent herbicides used in the Canadian prairies (triallate, trifluralin, ethalfluralin. The developed GC-EI/SIM, GC-NCI/SIM, and GC-NCI/SRM are suitable for the determination of pesticides in air sample extracts at concentrations <100 pg µL -1 (< 100 pg m -3 in air. No one method could be used to analyze the range of pre-emergent herbicides, OPs, and OCs investigated. In general GC-NCI/SIM provided the lowest method detection limits (MDLs commonly 2.5-10 pg µL -1 along with best confirmation (<25% RSD of ion ratio, while GC-NCI/SRM is recommended for use where added selectivity or confirmation is required (such as parathion-ethyl, tokuthion, carbofenothion. GC-EI/SRM at concentration < 100 pg µL -1 was not suitable for most pesticides. GC-EI/SIM was more prone to interference issues than NCI methods, but gave good sensitivity (MDLs 1-10 pg µL -1 for pesticides with poor NCI response (OPs: sulfotep, phorate, aspon, ethion, and OCs: alachlor, aldrin, perthane, and DDE, DDD, DDT.

  19. Comparative analyses of the chemical and sensory parameters and consumer preference of a semi-dried smoked meat product (cabanossi) produced with warthog (Phacochoerus africanus) and domestic pork meat.

    Science.gov (United States)

    Swanepoel, Monlee; Leslie, Alison J; Hoffman, Louwrens C

    2016-04-01

    The study compared the chemical and sensory characteristics and consumer preference of a semi-dried, cured meat product, cabanossi, produced with warthog meat and with domestic pork. The warthog and pork cabanossi had similar total moisture (59.0%±2.07 and 54.3%±1.26) and protein (26.3%±2.20 and 24.2%±2.15) contents, while the warthog cabanossi was lower in total fat content (6.9%±1.01) compared to pork cabanossi (13.7%±1.77, P=0.007). Descriptive sensory analysis found that the warthog cabanossi appeared darker red (P=0.001) and less fatty (P=0.001), while the pork cabanossi had a higher overall pork flavour (P=0.001). There were no differences in consumer preference of the appearance and taste between the two types of cabanossi, while the majority of consumers (91%) supported the use of game meat in meat products. The study concluded that warthog meat can be used in processed products without compromising the associated technical or organoleptic properties. Copyright © 2015 Elsevier Ltd. All rights reserved.

  20. Structure, spectroscopic analyses (FT-IR and NMR), vibrational study, chemical reactivity and molecular docking study on 3,3'-((4-(trifluoromethyl)phenyl)methylene)bis(2-hydroxynaphthalene-1,4-dione), a promising anticancerous bis-lawsone derivative

    Science.gov (United States)

    Yadav, Krishna Kant; Kumar, Abhishek; Kumar, Amarendra; Misra, Neeraj; Brahmachari, Goutam

    2018-02-01

    Lawsone (2-hydroxy-1,4-naphthoquinone)has been evaluated to possess a wide range of biological and pharmacological activities. The interesting structural pattern of lawsone coupled with its so-called multifaceted pharmacological potential have made this scaffolds useful in certain chemical processes, particularly in synthesizing ligands for metal complexations, and also few of its derivatives have shown a number of biological activities. The equilibrium geometry of 3,3‧-((4-(trifluoromethyl)phenyl)methylene)bis(2-hydroxynaphthalene-1,4-dione) (1; TPMHD), a promising anticancerous lawsone derivative, has been determined and analyzed at DFT method employingB3LYP/6-311++G(d,p) level of theory. The reactivity descriptors such as Fukui functions and HOMO-LUMO gap are calculated and discussed. The infrared spectra of TPMHD(1) are calculated and compared with the experimentally observed ones. Moreover, 1H and 13C NMR spectra have been calculated by using the gauge independent atomic orbital method. The docking studies reveal that the TPMHD has strong binding affinity toward target protein 2SHP. Thus the compound has a possible use as a drug in cancer therapy. The study suggests further investigation on TPMHD for their in-depth biological and pharmaceutical importance.

  1. 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.

  2. Chemically stabilized soils.

    Science.gov (United States)

    2009-12-01

    The objective of this study was to conduct laboratory evaluations to quantify the effects of compaction and moisture conditions on the strength of chemically treated soils typical utilized in pavement construction in Mississippi.

  3. Mineral and chemical composition of rock core and surface gas composition in Horonobe Underground Research Laboratory project. Phase 1

    International Nuclear Information System (INIS)

    Hiraga, Naoto; Ishii, Eiichi

    2008-02-01

    The following three kinds of analyses were conducted for the 1st phase of the Horonobe Underground Research Laboratory Project. Mineral composition analysis of core sample. Whole rock chemical composition analysis of core sample. Surface gas composition analysis. This document summarizes the results of these analyses. (author)

  4. Cosmetics Europe compilation of historical serious eye damage/eye irritation in vivo data analysed by drivers of classification to support the selection of chemicals for development and evaluation of alternative methods/strategies: the Draize eye test Reference Database (DRD).

    Science.gov (United States)

    Barroso, João; Pfannenbecker, Uwe; Adriaens, Els; Alépée, Nathalie; Cluzel, Magalie; De Smedt, Ann; Hibatallah, Jalila; Klaric, Martina; Mewes, Karsten R; Millet, Marion; Templier, Marie; McNamee, Pauline

    2017-02-01

    A thorough understanding of which of the effects assessed in the in vivo Draize eye test are responsible for driving UN GHS/EU CLP classification is critical for an adequate selection of chemicals to be used in the development and/or evaluation of alternative methods/strategies and for properly assessing their predictive capacity and limitations. For this reason, Cosmetics Europe has compiled a database of Draize data (Draize eye test Reference Database, DRD) from external lists that were created to support past validation activities. This database contains 681 independent in vivo studies on 634 individual chemicals representing a wide range of chemical classes. A description of all the ocular effects observed in vivo, i.e. degree of severity and persistence of corneal opacity (CO), iritis, and/or conjunctiva effects, was added for each individual study in the database, and the studies were categorised according to their UN GHS/EU CLP classification and the main effect driving the classification. An evaluation of the various in vivo drivers of classification compiled in the database was performed to establish which of these are most important from a regulatory point of view. These analyses established that the most important drivers for Cat 1 Classification are (1) CO mean ≥ 3 (days 1-3) (severity) and (2) CO persistence on day 21 in the absence of severity, and those for Cat 2 classification are (3) CO mean ≥ 1 and (4) conjunctival redness mean ≥ 2. Moreover, it is shown that all classifiable effects (including persistence and CO = 4) should be present in ≥60 % of the animals to drive a classification. As a consequence, our analyses suggest the need for a critical revision of the UN GHS/EU CLP decision criteria for the Cat 1 classification of chemicals. Finally, a number of key criteria are identified that should be taken into consideration when selecting reference chemicals for the development, evaluation and/or validation of alternative methods and

  5. CONDUCTIVITY OF DONKEY MILK

    Directory of Open Access Journals (Sweden)

    F. Conte

    2009-06-01

    Full Text Available The electrical conductivity (EC of milk is considered as one of the most important parameters which supports the diagnosis of mastitis in cows.Milk ions have a considerable influence on EC and their concentrations vary depending on animal species, season, lactation stage, etc. Some components of milk can change the EC, e.g. lactose. A negative correlation between EC values and the concentration of lactose is noticed, as a consequence of the inverse relation between this disaccharide and the chlorine content in milk. Fat and casein contents exert some influence on the EC, too. This study provides preliminary results on the physiological EC values in donkey milk and aims to highlight any correlation with some of its chemical-physical parameters and Somatic Cell Count (SCC. Mean EC value in donkey milk was found to be 3.57 mS. Statistically significant correlations were found between EC and SCC (r = 0.57 , p < 0.01 and between EC and (r = 0.30 , p < 0.05. The EC and lactose were not correlated although a reduction of EC was often observed when the lactose content increased, as reported in the literature for bovine milk. According to the EC can be considered as a reliable parameter to identify any breast disorder, taking into account the physiological factors that influence EC.

  6. Surface exchange kinetics and chemical diffusivities of BaZr{sub 0.2}Ce{sub 0.65}Y{sub 0.15}O{sub 3−δ} by electrical conductivity relaxation

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Dae-Kwang; Jeon, Sang-Yun; Singh, Bhupendra [Ionics Lab, School of Materials Science and Engineering, Chonnam National University, 77 Yongbong-ro, Buk-gu, Gwang-Ju 500-757 (Korea, Republic of); Park, Jun-Young [Department of Advanced Materials Engineering, Sejong University, Seoul 143-747 (Korea, Republic of); Song, Sun-Ju, E-mail: song@chonnam.ac.kr [Ionics Lab, School of Materials Science and Engineering, Chonnam National University, 77 Yongbong-ro, Buk-gu, Gwang-Ju 500-757 (Korea, Republic of)

    2014-10-15

    Highlights: • Electrical conductivity relaxation in BaCe{sub 0.65}Zr{sub 0.2}Y{sub 0.15}O{sub 3−δ} was monitored. • Monotonic relaxation behavior was observed during oxidation/reduction. • Nonmonotonic twofold relaxation behavior was observed during hydration/dehydration. • Surface exchange coefficients and diffusivities of O and H were calculated. - Abstract: Perovskite-type oxide BaCe{sub 0.65}Zr{sub 0.2}Y{sub 0.15}O{sub 3−δ} (BCZY2015) was synthesized by a solid state reaction method. BCZY2015 samples were characterized by powder X-ray diffraction (XRD) and scanning electron microscopy (SEM). The time dependent variation in electrical conductivity of BCZY2015 was monitored during the oxidation/reduction in oxygen partial pressure (pO{sub 2}) range of −2.28 ⩽ log (pO{sub 2}/atm) ⩽ −0.68 at a fixed water vapor pressure (pH{sub 2}O), and during the hydration/dehydration in −3.15 ⩽ log (pH{sub 2}O/atm) ⩽ −2.35 range in air. The electrical conductivity showed a monotonic relaxation behavior by the ambipolar diffusion of V{sub o}{sup ··} and OH{sub o}{sup ·} during the oxidation/reduction and the relaxation process was governed by the diffusivity of oxygen (D-tilde{sub vO}). On the other hand, during the hydration/dehydration process, a non-monotonic twofold relaxation behavior was observed due to the decoupled diffusion of H and O components with the mediation of holes, and the conductivity relaxation process was governed by the diffusivities of both H (D-tilde{sub iH}) and O (D-tlde{sub vH}). The values of surface exchange coefficients and diffusivities of oxygen and hydrogen were calculated from Fick’s second law by the nonlinear least squares fitting of the conductivity data, as proposed by Yoo et al. (2008)

  7. Risk analyses of nuclear power plants

    International Nuclear Information System (INIS)

    Jehee, J.N.T.; Seebregts, A.J.

    1991-02-01

    Probabilistic risk analyses of nuclear power plants are carried out by systematically analyzing the possible consequences of a broad spectrum of causes of accidents. The risk can be expressed in the probabilities for melt down, radioactive releases, or harmful effects for the environment. Following risk policies for chemical installations as expressed in the mandatory nature of External Safety Reports (EVRs) or, e.g., the publication ''How to deal with risks'', probabilistic risk analyses are required for nuclear power plants

  8. Multidimensional Heat Conduction

    DEFF Research Database (Denmark)

    Rode, Carsten

    1998-01-01

    Analytical theory of multidimensional heat conduction. General heat conduction equation in three dimensions. Steay state, analytical solutions. The Laplace equation. Method of separation of variables. Principle of superposition. Shape factors. Transient, multidimensional heat conduction....

  9. Thermal Conductivity of Foam Glass

    DEFF Research Database (Denmark)

    Petersen, Rasmus Rosenlund; König, Jakob; Yue, Yuanzheng

    Due to the increased focus on energy savings and waste recycling foam glass materials have gained increased attention. The production process of foam glass is a potential low-cost recycle option for challenging waste, e.g. CRT glass and industrial waste (fly ash and slags). Foam glass is used...... as thermal insulating material in building and chemical industry. The large volume of gas (porosity 90 – 95%) is the main reason of the low thermal conductivity of the foam glass. If gases with lower thermal conductivity compared to air are entrapped in the glass melt, the derived foam glass will contain...... only closed pores and its overall thermal conductivity will be much lower than that of the foam glass with open pores. In this work we have prepared foam glass using different types of recycled glasses and different kinds of foaming agents. This enabled the formation of foam glasses having gas cells...

  10. Conducting Polymer 3D Microelectrodes

    Directory of Open Access Journals (Sweden)

    Jenny Emnéus

    2010-12-01

    Full Text Available Conducting polymer 3D microelectrodes have been fabricated for possible future neurological applications. A combination of micro-fabrication techniques and chemical polymerization methods has been used to create pillar electrodes in polyaniline and polypyrrole. The thin polymer films obtained showed uniformity and good adhesion to both horizontal and vertical surfaces. Electrodes in combination with metal/conducting polymer materials have been characterized by cyclic voltammetry and the presence of the conducting polymer film has shown to increase the electrochemical activity when compared with electrodes coated with only metal. An electrochemical characterization of gold/polypyrrole electrodes showed exceptional electrochemical behavior and activity. PC12 cells were finally cultured on the investigated materials as a preliminary biocompatibility assessment. These results show that the described electrodes are possibly suitable for future in-vitro neurological measurements.

  11. The chemical juggernaut.

    Science.gov (United States)

    Cadbury, D

    1997-01-01

    Man-made chemicals pervade and support every aspect of modern living. The chemical industry has become such a powerful force in the global economy, sales of synthetic chemicals and products derived from them constitute well in excess of a third of the world's gross national product. But, these man-made chemicals are also 'elixirs of death,' the symbol of human destruction. Laboratory tests have shown that a number of chemicals in common use possess a remarkable property: they can weakly mimic or modify the action of human hormones. It has been proven that some chemicals found in plastics, pesticides, and industrial products are weakly estrogenic, modifying the action of the female hormone. In addition, other chemicals affect the male hormones, androgens, or anti-androgens; others are thought to target different hormone systems, such as thyroid and adrenal glands. Many research studies are being conducted to establish the impact of chemicals on human health. Of special concern are the rising incidence of testicular cancer, decline in human sperm counts, and the sharp rise of breast cancer. In conclusion, although there is a worldwide debate on the effects of chemical exposure on humans, the significance of findings for human health, concerning testicular and breast cancer, are still unknown. An international treaty is called for to control the use of the persistent hormonally active chemicals.

  12. Laser Beam Focus Analyser

    DEFF Research Database (Denmark)

    Nielsen, Peter Carøe; Hansen, Hans Nørgaard; Olsen, Flemming Ove

    2007-01-01

    the obtainable features in direct laser machining as well as heat affected zones in welding processes. This paper describes the development of a measuring unit capable of analysing beam shape and diameter of lasers to be used in manufacturing processes. The analyser is based on the principle of a rotating......The quantitative and qualitative description of laser beam characteristics is important for process implementation and optimisation. In particular, a need for quantitative characterisation of beam diameter was identified when using fibre lasers for micro manufacturing. Here the beam diameter limits...... mechanical wire being swept through the laser beam at varying Z-heights. The reflected signal is analysed and the resulting beam profile determined. The development comprised the design of a flexible fixture capable of providing both rotation and Z-axis movement, control software including data capture...

  13. Contesting Citizenship: Comparative Analyses

    DEFF Research Database (Denmark)

    Siim, Birte; Squires, Judith

    2007-01-01

    importance of particularized experiences and multiple ineequality agendas). These developments shape the way citizenship is both practiced and analysed. Mapping neat citizenship modles onto distinct nation-states and evaluating these in relation to formal equality is no longer an adequate approach....... Comparative citizenship analyses need to be considered in relation to multipleinequalities and their intersections and to multiple governance and trans-national organisinf. This, in turn, suggests that comparative citizenship analysis needs to consider new spaces in which struggles for equal citizenship occur...

  14. Conducting compositions of matter

    Science.gov (United States)

    Viswanathan, Tito (Inventor)

    2000-01-01

    The invention provides conductive compositions of matter, as well as methods for the preparation of the conductive compositions of matter, solutions comprising the conductive compositions of matter, and methods of preparing fibers or fabrics having improved anti-static properties employing the conductive compositions of matter.

  15. Numerical tables. Physical and chemical analyses of Rhine water 1984

    International Nuclear Information System (INIS)

    1984-01-01

    Tables present the methods of analysis and the data obtained on inorganic, organic, and radioactive impurities in Rhine water. The measuring stations were located in Switzerland, France, West Germany, and the Netherlands. (HP) [de

  16. Roman bronze artefacts from Thamusida (Morocco): Chemical and phase analyses

    Energy Technology Data Exchange (ETDEWEB)

    Gliozzo, E., E-mail: gliozzo@unisi.i [Dipartimento di Scienze della Terra, Universita di Siena, via Laterina 8, 53100 Siena (Italy); Kockelmann, W., E-mail: winfried.kockelmann@stfc.ac.u [Science and Technology Facilities Council, Rutherford Appleton Laboratory, Harwell Science and Innovation Campus, Didcot OX11 0QX (United Kingdom); Bartoli, L., E-mail: bartoli@ifac.cnr.i [Istituto dei Sistemi Complessi, Consiglio nazionale delle Ricerche, Via Madonna del Piano 10, 50019 Sesto Fiorentino (Italy); Tykot, R.H., E-mail: rtykot@usf.ed [Department of Anthropology, University of South Florida, Tampa, FL 33620 (United States)

    2011-02-01

    Twenty-six objects (1st to the 3rd century AD) found at the archaeological site of Thamusida (Morocco), which is a military settlement between the 1st and the 3rd century AD, have been investigated by means of portable X-ray fluorescence and time of flight-neutron diffraction. The combination of element-sensitive X-ray fluorescence and structure-sensitive neutron diffraction yields, in a totally non-destructive way, the necessary information to discriminate the copper alloy from corrosion and alteration layers. Results allowed dividing the repertory into five groups: (a) unalloyed copper, (b) binary alloys made of Cu and Sn, frequently leaded; (c) unleaded binary alloys made of Cu and Zn; (d) ternary alloys made of Cu, Sn and Zn, both leaded and unleaded; (e) quaternary alloys made of Cu, Sn, Zn and As. The choice of alloy is heterogeneous, mainly depending on availability and costs of raw and/or scrap materials and on technological constraints. Interestingly, the reconstruction obtained for Thamusida could either anticipate the important change in the Roman use of copper alloys generally referred as 'zinc decline', or more likely, indicate that brass never conspicuously entered the local metal-working activities of this military site.

  17. Physical-chemical analyses of irradiated papayas ( Carica papaya L.)

    Science.gov (United States)

    Camargo, R. J.; Tadini, C. C.; Sabato, S. F.

    2007-11-01

    Papaya is cultivated in Espírito Santo State/Brazil and as it stands up to irradiation, it is important to validate this technology, since it is already being applied in some countries. Penetration energy, ratio (relation between soluble solids and titrable acidity) and skin color were evaluated to verify the influence of four different doses of irradiation (0.0, 0.5, 0.75 and 1.00 kGy) on papayas, during 21 days. As a result for the skin color and the penetration energy, it was found that in the first days after irradiation, these variables increased with increase in radiation dose; however, after a time lapse, the tendency inverted and the irradiated fruits had a slower ripening process. For the ratio, a very important variable that it is responsible for the fruit taste, no difference was found between irradiated and the control fruit. Color and texture measurements are dependent on the storage temperature.

  18. Physical-chemical analyses of irradiated papayas (Carica papaya L.)

    International Nuclear Information System (INIS)

    Camargo, R.J.; Tadini, C.C.; Sabato, S.F.

    2007-01-01

    Papaya is cultivated in Espirito Santo State/Brazil and as it stands up to irradiation, it is important to validate this technology, since it is already being applied in some countries. Penetration energy, ratio (relation between soluble solids and titrable acidity) and skin color were evaluated to verify the influence of four different doses of irradiation (0.0, 0.5, 0.75 and 1.00 kGy) on papayas, during 21 days. As a result for the skin color and the penetration energy, it was found that in the first days after irradiation, these variables increased with increase in radiation dose; however, after a time lapse, the tendency inverted and the irradiated fruits had a slower ripening process. For the ratio, a very important variable that it is responsible for the fruit taste, no difference was found between irradiated and the control fruit. Color and texture measurements are dependent on the storage temperature

  19. physico-chemical and bacteriological analyses of drinking water

    African Journals Online (AJOL)

    2012-07-02

    Jul 2, 2012 ... The physical reality of life is defined by water [7]. Water is a unique liquid, ... sure of the biological balance or health of the aquatic environment. A wide ... During the field work activities, a hand-held Ger- man GPS Model 12 XL ...

  20. Numerical tables on physical and chemical analyses of Rhine water

    International Nuclear Information System (INIS)

    1982-01-01

    Tables on the places of measurement, the sampling methods and the methods of analysis used. The numerical tables of the measurement results are broken down in general parameters, organic, entrophicating and anorganic substances, orgnic micro-pollutants and radioactivity. (GG) [de

  1. Risico-analyse brandstofpontons

    NARCIS (Netherlands)

    Uijt de Haag P; Post J; LSO

    2001-01-01

    Voor het bepalen van de risico's van brandstofpontons in een jachthaven is een generieke risico-analyse uitgevoerd. Er is een referentiesysteem gedefinieerd, bestaande uit een betonnen brandstofponton met een relatief grote inhoud en doorzet. Aangenomen is dat de ponton gelegen is in een

  2. Fast multichannel analyser

    Energy Technology Data Exchange (ETDEWEB)

    Berry, A; Przybylski, M M; Sumner, I [Science Research Council, Daresbury (UK). Daresbury Lab.

    1982-10-01

    A fast multichannel analyser (MCA) capable of sampling at a rate of 10/sup 7/ s/sup -1/ has been developed. The instrument is based on an 8 bit parallel encoding analogue to digital converter (ADC) reading into a fast histogramming random access memory (RAM) system, giving 256 channels of 64 k count capacity. The prototype unit is in CAMAC format.

  3. A fast multichannel analyser

    International Nuclear Information System (INIS)

    Berry, A.; Przybylski, M.M.; Sumner, I.

    1982-01-01

    A fast multichannel analyser (MCA) capable of sampling at a rate of 10 7 s -1 has been developed. The instrument is based on an 8 bit parallel encoding analogue to digital converter (ADC) reading into a fast histogramming random access memory (RAM) system, giving 256 channels of 64 k count capacity. The prototype unit is in CAMAC format. (orig.)

  4. Chemical and mineralogical analyses of Roman amphorae from Augustan period recovered at the production center of Sant Antoni de Calonge (Gerona, Spain); Analisis quimico y mineralogico de un conjunto de anforas romanas de epoca augustea procedentes del centro productor de Sant Antoni de Calonge (Gerona)

    Energy Technology Data Exchange (ETDEWEB)

    Vila Socias, L.; Prats Pico, N.; Buxeda Garrigos, J.

    2016-05-01

    Amphorae were the most popular transport vessels used to ship wine and other commodities in Antiquity. This paper reports the results of the analyses of 38 samples of several Roman amphorae types recovered at Calonge (Gerona, Spain). Chemical composition of individuals have been obtained by means of XRF. Equivalent firing temperatures have been estimated by XRD and further refiring experiments have been performed. The results suggest the existence of two different clay pastes among individuals analyzed, most of which were fired at the range 900-1000 degree centigrade. Moreover, it is argued that craftsmen did not follow highly standardized paste preparation process during the first activity period of the workshop. The results are discussed in terms of production technology and standardization. (Author)

  5. Proton-conducting cerate ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Pederson, L.R.; Coffey, G.W.; Bates, J.L.; Weber, W.J. [Pacific Northwest National Lab., Richland, WA (United States)

    1996-08-01

    Single-cell solid oxide fuel cells were constructed using strontium cerate as the electrolyte and their performance tested. Like certain zirconates, hafnates, and tantalates, the cerate perovskites are among a class of solid electrolytes that conduct protons at elevated temperatures. Depending on the temperature and chemical environment, these ceramics also support electronic and oxygen ion currents. A maximum power output of {approx}100 mW per cm{sup 2} electrolyte surface area was obtained at 900{degrees}C using 4% hydrogen as the fuel and air as the oxidant. A series of rare earth/ceria/zirconia were prepared and their electrical properties characterized. Rare earth dopants included ytterbia, yttria, terbia, and europia. Ionic conductivities were highest for rare earth/ceria and rare earth zirconia compositions; a minimum in ionic conductivity for all series were found for equimolar mixtures of ceria and zirconia. Cerium oxysulfide is of interest in fossil energy applications because of its high chemical stability and refractory nature. An alternative synthesis route to preparing cerium oxysulfide powders has been developed using combustion techniques.

  6. Chemical Peels

    Science.gov (United States)

    ... for Every Season How to Choose the Best Skin Care Products In This Section Dermatologic Surgery What is dermatologic ... for Every Season How to Choose the Best Skin Care Products Chemical Peels Uses for Chemical Peels Learn more ...

  7. Chemical Oscillations

    Indian Academy of Sciences (India)

    IMTECH),. Chandigarh. Praveen Kumar is pursuing his PhD in chemical dynamics at. Panjab University,. Chandigarh. Keywords. Chemical oscillations, autoca-. talYSis, Lotka-Volterra model, bistability, hysteresis, Briggs-. Rauscher reaction.

  8. Chemical ecotoxicology

    International Nuclear Information System (INIS)

    Paasivirta, J.

    1991-01-01

    This book discusses risk assessment, chemical cycles, structure-activity relations, organohalogens, oil residues, mercury, sampling and analysis of trace chemicals, and emissions from the forestry industry. Topics include: Cycles of chemicals in the environment. Rick assessment and management, strucuture and toxicity, sampling and analysis of trace chemicals in environment, interpretation of the environmental analysis results, mercury in the environment, organohalogen compounds in the environment, emissions from forestry industry, oil residues in the environment: oil spills in the marine environment

  9. Use of stream water pH and specific conductance measurements to identify ground water discharges of fly ash leachate

    International Nuclear Information System (INIS)

    Price, R.M.

    1992-01-01

    Low pH and high specific conductance are typical chemical characteristics of coal fly ash leachate. Measurements of these parameters in streams adjacent to a fly ash facility were used to identify areas of ground water discharge into the streams. In-situ specific conductance and pH were determined at approximately 50 surface water stations from on-site and off-site streams. The results of the in-situ determinations were used to select twelve surface water stations for more detailed chemical analyses. The chemical character of the stream water affected by ground water discharges was similar to the water quality of sedimentation ponds which received drainage from the fly ash embankment. The results indicated that in-situ measurements of indicator parameters such as pH and specific conductance can be used as a screening method for identifying surface water quality impacts at fly ash facilities

  10. Chemical sensor

    Science.gov (United States)

    Rauh, R. David (Inventor)

    1990-01-01

    A sensor for detecting a chemical substance includes an insertion element having a structure which enables insertion of the chemical substance with a resulting change in the bulk electrical characteristics of the insertion element under conditions sufficient to permit effective insertion; the change in the bulk electrical characteristics of the insertion element is detected as an indication of the presence of the chemical substance.

  11. Chemical evaluation of electronic cigarettes.

    Science.gov (United States)

    Cheng, Tianrong

    2014-05-01

    To review the available evidence evaluating the chemicals in refill solutions, cartridges, aerosols and environmental emissions of electronic cigarettes (e-cigarettes). Systematic literature searches were conducted to identify research related to e-cigarettes and chemistry using 5 reference databases and 11 search terms. The search date range was January 2007 to September 2013. The search yielded 36 articles, of which 29 were deemed relevant for analysis. The levels of nicotine, tobacco-specific nitrosamines (TSNAs), aldehydes, metals, volatile organic compounds (VOCs), flavours, solvent carriers and tobacco alkaloids in e-cigarette refill solutions, cartridges, aerosols and environmental emissions vary considerably. The delivery of nicotine and the release of TSNAs, aldehydes and metals are not consistent across products. Furthermore, the nicotine level listed on the labels of e-cigarette cartridges and refill solutions is often significantly different from measured values. Phenolic compounds, polycyclic aromatic hydrocarbons and drugs have also been reported in e-cigarette refill solutions, cartridges and aerosols. Varying results in particle size distributions of particular matter emissions from e-cigarettes across studies have been observed. Methods applied for the generation and chemical analyses of aerosols differ across studies. Performance characteristics of e-cigarette devices also vary across and within brands. Additional studies based on knowledge of e-cigarette user behaviours and scientifically validated aerosol generation and chemical analysis methods would be helpful in generating reliable measures of chemical quantities. This would allow comparisons of e-cigarette aerosol and traditional smoke constituent levels and would inform an evaluation of the toxicity potential of e-cigarettes.

  12. Chemical evaluation of electronic cigarettes

    Science.gov (United States)

    Cheng, Tianrong

    2014-01-01

    Objective To review the available evidence evaluating the chemicals in refill solutions, cartridges, aerosols and environmental emissions of electronic cigarettes (e-cigarettes). Methods Systematic literature searches were conducted to identify research related to e-cigarettes and chemistry using 5 reference databases and 11 search terms. The search date range was January 2007 to September 2013. The search yielded 36 articles, of which 29 were deemed relevant for analysis. Results The levels of nicotine, tobacco-specific nitrosamines (TSNAs), aldehydes, metals, volatile organic compounds (VOCs), flavours, solvent carriers and tobacco alkaloids in e-cigarette refill solutions, cartridges, aerosols and environmental emissions vary considerably. The delivery of nicotine and the release of TSNAs, aldehydes and metals are not consistent across products. Furthermore, the nicotine level listed on the labels of e-cigarette cartridges and refill solutions is often significantly different from measured values. Phenolic compounds, polycyclic aromatic hydrocarbons and drugs have also been reported in e-cigarette refill solutions, cartridges and aerosols. Varying results in particle size distributions of particular matter emissions from e-cigarettes across studies have been observed. Methods applied for the generation and chemical analyses of aerosols differ across studies. Performance characteristics of e-cigarette devices also vary across and within brands. Conclusions Additional studies based on knowledge of e-cigarette user behaviours and scientifically validated aerosol generation and chemical analysis methods would be helpful in generating reliable measures of chemical quantities. This would allow comparisons of e-cigarette aerosol and traditional smoke constituent levels and would inform an evaluation of the toxicity potential of e-cigarettes. PMID:24732157

  13. Possible future HERA analyses

    International Nuclear Information System (INIS)

    Geiser, Achim

    2015-12-01

    A variety of possible future analyses of HERA data in the context of the HERA data preservation programme is collected, motivated, and commented. The focus is placed on possible future analyses of the existing ep collider data and their physics scope. Comparisons to the original scope of the HERA pro- gramme are made, and cross references to topics also covered by other participants of the workshop are given. This includes topics on QCD, proton structure, diffraction, jets, hadronic final states, heavy flavours, electroweak physics, and the application of related theory and phenomenology topics like NNLO QCD calculations, low-x related models, nonperturbative QCD aspects, and electroweak radiative corrections. Synergies with other collider programmes are also addressed. In summary, the range of physics topics which can still be uniquely covered using the existing data is very broad and of considerable physics interest, often matching the interest of results from colliders currently in operation. Due to well-established data and MC sets, calibrations, and analysis procedures the manpower and expertise needed for a particular analysis is often very much smaller than that needed for an ongoing experiment. Since centrally funded manpower to carry out such analyses is not available any longer, this contribution not only targets experienced self-funded experimentalists, but also theorists and master-level students who might wish to carry out such an analysis.

  14. Biomass feedstock analyses

    Energy Technology Data Exchange (ETDEWEB)

    Wilen, C.; Moilanen, A.; Kurkela, E. [VTT Energy, Espoo (Finland). Energy Production Technologies

    1996-12-31

    The overall objectives of the project `Feasibility of electricity production from biomass by pressurized gasification systems` within the EC Research Programme JOULE II were to evaluate the potential of advanced power production systems based on biomass gasification and to study the technical and economic feasibility of these new processes with different type of biomass feed stocks. This report was prepared as part of this R and D project. The objectives of this task were to perform fuel analyses of potential woody and herbaceous biomasses with specific regard to the gasification properties of the selected feed stocks. The analyses of 15 Scandinavian and European biomass feed stock included density, proximate and ultimate analyses, trace compounds, ash composition and fusion behaviour in oxidizing and reducing atmospheres. The wood-derived fuels, such as whole-tree chips, forest residues, bark and to some extent willow, can be expected to have good gasification properties. Difficulties caused by ash fusion and sintering in straw combustion and gasification are generally known. The ash and alkali metal contents of the European biomasses harvested in Italy resembled those of the Nordic straws, and it is expected that they behave to a great extent as straw in gasification. Any direct relation between the ash fusion behavior (determined according to the standard method) and, for instance, the alkali metal content was not found in the laboratory determinations. A more profound characterisation of the fuels would require gasification experiments in a thermobalance and a PDU (Process development Unit) rig. (orig.) (10 refs.)

  15. The Nature of the Phonon Spectrum and the Analysis of Lattice Thermal Conductivity; Nature du Spectre des Phonons et Analyse de la Conductibilite Thermique du Reseau; Kharakter fononnogo spektra i analiz teploprovodnosti reshetki; Naturaleza del Espectro Fononico y Analisis de la Conductividad Termica Reticular

    Energy Technology Data Exchange (ETDEWEB)

    Joshi, S. K.; Sharma, K. C. [Physics Department, Allahabad University, Allahabad (India)

    1965-04-15

    An analysis of lattice thermal conductivity is presented, wherein a more realistic phonon spectrum is utilized than the usual Debye-like phonon spectrum consisting of one average acoustic branch. We have first used an anisotropic continuum dispersive model in our calculation of the temperature dependence of the lattice thermal conductivity of germanium. The approach that we have utilized in this calculation is a modified version of Callaway's formulation. Houston's six- and three-term integration procedures are used in evaluating rather formidable integrals over lattice frequencies. Suitable prevalent expressions for relaxation times for boundary and impurity scatterings and three-phonon normal and Umklapp processes are used. A good fit to the experimental data of Holland and Slack and Glassbrenner is obtained for germanium from 2 to 1000 Degree-Sign K by adjusting the four constants occurring in the integrals. On the face of reliable neutron spectroscopic evidence, we know that germanium has very disperse transverse branches and for them an anisotropic continuum dispersive model also yields a poor representation. We therefore thought it appropriate to utilize the very elaborate shell model for the lattice dynamics of germanium put forth by Cochran. With a proper adjustment of the parameters entering in our formulation for the calculation of lattice thermal conductivity, we again find a good fit with the experimental data. We are led to a conclusion that the nature of the phonon spectrum does not greatly influence the analysis of lattice thermal conductivity data according to current approaches and the niceties of the phonon spectrum are lost in the adjustment of the various parameters involved. It is felt that instead of putting too much labour in evaluating the tedious integrals for more realistic lattice dynamical models, it is better to investigate the validity of various relaxation time assumptions that have gone into these integrals. (author) [French] Les

  16. Nerve conduction velocity

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/003927.htm Nerve conduction velocity To use the sharing features on this page, please enable JavaScript. Nerve conduction velocity (NCV) is a test to see ...

  17. Conducting Polymeric Materials

    DEFF Research Database (Denmark)

    Hvilsted, Søren

    2016-01-01

    The overall objective of this collection is to provide the most recent developments within the various areas of conducting polymeric materials. The conductivity of polymeric materials is caused by electrically charged particles, ions, protons and electrons. Materials in which electrons...

  18. Amazing variational approach to chemical reactions

    OpenAIRE

    Fernández, Francisco M.

    2009-01-01

    In this letter we analyse an amazing variational approach to chemical reactions. Our results clearly show that the variational expressions are unsuitable for the analysis of empirical data obtained from chemical reactions.

  19. Conduction cooled compact laser for chemcam instrument

    Science.gov (United States)

    Faure, B.; Saccoccio, M.; Maurice, S.; Durand, E.; Derycke, C.

    2017-11-01

    A new conduction cooled compact laser for Laser Induced Breakdown Spectroscopy (LIBS) on Mars is presented. The laser provides pulses with energy higher than 30mJ at 1μm of wavelength with a good spatial quality. Three development prototypes of this laser have been built and functional and environmental tests have been done. Then, the Qualification and Flight models have been developed and delivered. A spare model is now developed. This laser will be mounted on the ChemCam Instrument of the NASA mission MSL 2009. ChemCam Instrument is developed in collaboration between France (CESR and CNES) and USA (LANL). The goal of this Instrument is to study the chemical composition of Martian rocks. A laser source (subject of this presentation) emits a pulse which is focused by a telescope. It creates a luminous plasma on the rock; the light of this plasma is then analysed by three spectrometers to obtain information on the composition of the rock. The laser source is developed by the French company Thales Laser, with a technical support from CNES and CESR. This development is funded by CNES. The laser is compact, designed to work in burst mode. It doesn't require any active cooling.

  20. Electrically conductive composite material

    Science.gov (United States)

    Clough, Roger L.; Sylwester, Alan P.

    1989-01-01

    An electrically conductive composite material is disclosed which comprises a conductive open-celled, low density, microcellular carbon foam filled with a non-conductive polymer or resin. The composite material is prepared in a two-step process consisting of first preparing the microcellular carbon foam from a carbonizable polymer or copolymer using a phase separation process, then filling the carbon foam with the desired non-conductive polymer or resin. The electrically conductive composites of the present invention has a uniform and consistant pattern of filler distribution, and as a result is superior over prior art materials when used in battery components, electrodes, and the like.

  1. Physico-chemical, mineralogical and chemical considerations in ...

    African Journals Online (AJOL)

    ... pH (5.17 – 6.90) and EC (16.53 – 149.20ìS/cm). Values from physico-chemical analyses, secondary minerals abundance index (SMAI) and chemical index of alteration (CIA) of the soils were reflective of particles with high potential for sliding. With major contributions from favourable slope, seismic and hydrologic forces, ...

  2. AMS analyses at ANSTO

    Energy Technology Data Exchange (ETDEWEB)

    Lawson, E.M. [Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW (Australia). Physics Division

    1998-03-01

    The major use of ANTARES is Accelerator Mass Spectrometry (AMS) with {sup 14}C being the most commonly analysed radioisotope - presently about 35 % of the available beam time on ANTARES is used for {sup 14}C measurements. The accelerator measurements are supported by, and dependent on, a strong sample preparation section. The ANTARES AMS facility supports a wide range of investigations into fields such as global climate change, ice cores, oceanography, dendrochronology, anthropology, and classical and Australian archaeology. Described here are some examples of the ways in which AMS has been applied to support research into the archaeology, prehistory and culture of this continent`s indigenous Aboriginal peoples. (author)

  3. AMS analyses at ANSTO

    International Nuclear Information System (INIS)

    Lawson, E.M.

    1998-01-01

    The major use of ANTARES is Accelerator Mass Spectrometry (AMS) with 14 C being the most commonly analysed radioisotope - presently about 35 % of the available beam time on ANTARES is used for 14 C measurements. The accelerator measurements are supported by, and dependent on, a strong sample preparation section. The ANTARES AMS facility supports a wide range of investigations into fields such as global climate change, ice cores, oceanography, dendrochronology, anthropology, and classical and Australian archaeology. Described here are some examples of the ways in which AMS has been applied to support research into the archaeology, prehistory and culture of this continent's indigenous Aboriginal peoples. (author)

  4. [Chemical weapons and chemical terrorism].

    Science.gov (United States)

    Nakamura, Katsumi

    2005-10-01

    Chemical Weapons are kind of Weapons of Mass Destruction (WMD). They were used large quantities in WWI. Historically, large quantities usage like WWI was not recorded, but small usage has appeared now and then. Chemical weapons are so called "Nuclear weapon for poor countrys" because it's very easy to produce/possession being possible. They are categorized (1) Nerve Agents, (2) Blister Agents, (3) Cyanide (blood) Agents, (4) Pulmonary Agents, (5) Incapacitating Agents (6) Tear Agents from the viewpoint of human body interaction. In 1997 the Chemical Weapons Convention has taken effect. It prohibits chemical weapons development/production, and Organization for the Prohibition of Chemical Weapons (OPCW) verification regime contributes to the chemical weapons disposal. But possibility of possession/use of weapons of mass destruction by terrorist group represented in one by Matsumoto and Tokyo Subway Sarin Attack, So new chemical terrorism countermeasures are necessary.

  5. Analyses of MHD instabilities

    International Nuclear Information System (INIS)

    Takeda, Tatsuoki

    1985-01-01

    In this article analyses of the MHD stabilities which govern the global behavior of a fusion plasma are described from the viewpoint of the numerical computation. First, we describe the high accuracy calculation of the MHD equilibrium and then the analysis of the linear MHD instability. The former is the basis of the stability analysis and the latter is closely related to the limiting beta value which is a very important theoretical issue of the tokamak research. To attain a stable tokamak plasma with good confinement property it is necessary to control or suppress disruptive instabilities. We, next, describe the nonlinear MHD instabilities which relate with the disruption phenomena. Lastly, we describe vectorization of the MHD codes. The above MHD codes for fusion plasma analyses are relatively simple though very time-consuming and parts of the codes which need a lot of CPU time concentrate on a small portion of the codes, moreover, the codes are usually used by the developers of the codes themselves, which make it comparatively easy to attain a high performance ratio on the vector processor. (author)

  6. Uncertainty Analyses and Strategy

    International Nuclear Information System (INIS)

    Kevin Coppersmith

    2001-01-01

    The DOE identified a variety of uncertainties, arising from different sources, during its assessment of the performance of a potential geologic repository at the Yucca Mountain site. In general, the number and detail of process models developed for the Yucca Mountain site, and the complex coupling among those models, make the direct incorporation of all uncertainties difficult. The DOE has addressed these issues in a number of ways using an approach to uncertainties that is focused on producing a defensible evaluation of the performance of a potential repository. The treatment of uncertainties oriented toward defensible assessments has led to analyses and models with so-called ''conservative'' assumptions and parameter bounds, where conservative implies lower performance than might be demonstrated with a more realistic representation. The varying maturity of the analyses and models, and uneven level of data availability, result in total system level analyses with a mix of realistic and conservative estimates (for both probabilistic representations and single values). That is, some inputs have realistically represented uncertainties, and others are conservatively estimated or bounded. However, this approach is consistent with the ''reasonable assurance'' approach to compliance demonstration, which was called for in the U.S. Nuclear Regulatory Commission's (NRC) proposed 10 CFR Part 63 regulation (64 FR 8640 [DIRS 101680]). A risk analysis that includes conservatism in the inputs will result in conservative risk estimates. Therefore, the approach taken for the Total System Performance Assessment for the Site Recommendation (TSPA-SR) provides a reasonable representation of processes and conservatism for purposes of site recommendation. However, mixing unknown degrees of conservatism in models and parameter representations reduces the transparency of the analysis and makes the development of coherent and consistent probability statements about projected repository

  7. Mobile app for chemical detection

    Science.gov (United States)

    Klunder, Gregory; Cooper, Chadway R.; Satcher, Jr., Joe H.; Tekle, Ephraim A.

    2017-07-18

    The present invention incorporates the camera from a mobile device (phone, iPad, etc.) to capture an image from a chemical test kit and process the image to provide chemical information. A simple user interface enables the automatic evaluation of the image, data entry, gps info, and maintain records from previous analyses.

  8. Documentation of the heat conduction code TRANCO

    International Nuclear Information System (INIS)

    Callahan, G.D.

    1975-01-01

    A transient heat conduction code used for thermal, thermoelastic, thermoelastic/plastic, and thermo/viscoelastic analyses is presented. The code can solve two-dimensional X-Y and axially symmetric R-theta-z thermal problems with the following conditions: constant temperature, constant flux, convective, or adiabatic boundary conditions; time-dependent or constant internal heat generation; and anisotropic thermal conductivities

  9. Hazardous Chemicals

    Centers for Disease Control (CDC) Podcasts

    Chemicals are a part of our daily lives, providing many products and modern conveniences. With more than three decades of experience, The Centers for Disease Control and Prevention (CDC) has been in the forefront of efforts to protect and assess people's exposure to environmental and hazardous chemicals. This report provides information about hazardous chemicals and useful tips on how to protect you and your family from harmful exposure.

  10. Conceptual Chemical Process Design for Sustainability.

    Science.gov (United States)

    This chapter examines the sustainable design of chemical processes, with a focus on conceptual design, hierarchical and short-cut methods, and analyses of process sustainability for alternatives. The chapter describes a methodology for incorporating process sustainability analyse...

  11. Preparation, dielectric and a.c. conductivity studies on chemically ...

    African Journals Online (AJOL)

    user

    methods included alkali treatment, H2SO4 treatment, combined H2SO4, and alkali-thermal treatment. .... presence of impurities, lignin and cellulosic group and water dipoles present in sisal fibers ... groups; thereby making them more reactive .

  12. Electrical Conductivity of CUXS Thin Film Deposited by Chemical ...

    African Journals Online (AJOL)

    acer

    Nigerian Journal of Basic and Applied Science (2009), 17(2): 161-165. ISSN 0794-5698. Electrical ... Department of Physics, University of Abuja, P. M. B. 117, Abuja, Nigeria. [*Correspondence ... ease of handling and ease of application to.

  13. Alarms, Chemical

    Science.gov (United States)

    cited in applicable qualitative materiel requirements, small development requirements, technical characteristics, and other requirements and documentation that pertain to automatic chemical agent alarms.

  14. Chemical oceanography

    National Research Council Canada - National Science Library

    Millero, F.J

    1996-01-01

    Chemical Oceanography presents a comprehensive examination of the chemistry of oceans through discussions of such topics as descriptive physical oceanography, the composition of seawater and the major...

  15. Sapiness–sentiment analyser

    Directory of Open Access Journals (Sweden)

    Jánosi-Rancz Katalin Tünde

    2015-12-01

    Full Text Available In our ever-evolving world, the importance of social networks is bigger now than ever. The purpose of this paper is to develop a sentiment analyzer for the Hungarian language, which we can then use to analyze any text and conduct further experiments. One such experiment is an application which can interface with social networks, and run sentiment analysis on the logged-in users friends’ posts and comments, while the other experiment is the use of sentiment analysis in order to visualize the evolution of relationships between characters in a text.

  16. Electrically conductive cellulose composite

    Science.gov (United States)

    Evans, Barbara R.; O'Neill, Hugh M.; Woodward, Jonathan

    2010-05-04

    An electrically conductive cellulose composite includes a cellulose matrix and an electrically conductive carbonaceous material incorporated into the cellulose matrix. The electrical conductivity of the cellulose composite is at least 10 .mu.S/cm at 25.degree. C. The composite can be made by incorporating the electrically conductive carbonaceous material into a culture medium with a cellulose-producing organism, such as Gluconoacetobacter hansenii. The composites can be used to form electrodes, such as for use in membrane electrode assemblies for fuel cells.

  17. Kalman filter-based gap conductance modeling

    International Nuclear Information System (INIS)

    Tylee, J.L.

    1983-01-01

    Geometric and thermal property uncertainties contribute greatly to the problem of determining conductance within the fuel-clad gas gap of a nuclear fuel pin. Accurate conductance values are needed for power plant licensing transient analysis and for test analyses at research facilities. Recent work by Meek, Doerner, and Adams has shown that use of Kalman filters to estimate gap conductance is a promising approach. A Kalman filter is simply a mathematical algorithm that employs available system measurements and assumed dynamic models to generate optimal system state vector estimates. This summary addresses another Kalman filter approach to gap conductance estimation and subsequent identification of an empirical conductance model

  18. EEG analyses with SOBI.

    Energy Technology Data Exchange (ETDEWEB)

    Glickman, Matthew R.; Tang, Akaysha (University of New Mexico, Albuquerque, NM)

    2009-02-01

    The motivating vision behind Sandia's MENTOR/PAL LDRD project has been that of systems which use real-time psychophysiological data to support and enhance human performance, both individually and of groups. Relevant and significant psychophysiological data being a necessary prerequisite to such systems, this LDRD has focused on identifying and refining such signals. The project has focused in particular on EEG (electroencephalogram) data as a promising candidate signal because it (potentially) provides a broad window on brain activity with relatively low cost and logistical constraints. We report here on two analyses performed on EEG data collected in this project using the SOBI (Second Order Blind Identification) algorithm to identify two independent sources of brain activity: one in the frontal lobe and one in the occipital. The first study looks at directional influences between the two components, while the second study looks at inferring gender based upon the frontal component.

  19. Pathway-based analyses.

    Science.gov (United States)

    Kent, Jack W

    2016-02-03

    New technologies for acquisition of genomic data, while offering unprecedented opportunities for genetic discovery, also impose severe burdens of interpretation and penalties for multiple testing. The Pathway-based Analyses Group of the Genetic Analysis Workshop 19 (GAW19) sought reduction of multiple-testing burden through various approaches to aggregation of highdimensional data in pathways informed by prior biological knowledge. Experimental methods testedincluded the use of "synthetic pathways" (random sets of genes) to estimate power and false-positive error rate of methods applied to simulated data; data reduction via independent components analysis, single-nucleotide polymorphism (SNP)-SNP interaction, and use of gene sets to estimate genetic similarity; and general assessment of the efficacy of prior biological knowledge to reduce the dimensionality of complex genomic data. The work of this group explored several promising approaches to managing high-dimensional data, with the caveat that these methods are necessarily constrained by the quality of external bioinformatic annotation.

  20. Analysing Access Control Specifications

    DEFF Research Database (Denmark)

    Probst, Christian W.; Hansen, René Rydhof

    2009-01-01

    When prosecuting crimes, the main question to answer is often who had a motive and the possibility to commit the crime. When investigating cyber crimes, the question of possibility is often hard to answer, as in a networked system almost any location can be accessed from almost anywhere. The most...... common tool to answer this question, analysis of log files, faces the problem that the amount of logged data may be overwhelming. This problems gets even worse in the case of insider attacks, where the attacker’s actions usually will be logged as permissible, standard actions—if they are logged at all....... Recent events have revealed intimate knowledge of surveillance and control systems on the side of the attacker, making it often impossible to deduce the identity of an inside attacker from logged data. In this work we present an approach that analyses the access control configuration to identify the set...

  1. Network class superposition analyses.

    Directory of Open Access Journals (Sweden)

    Carl A B Pearson

    Full Text Available Networks are often used to understand a whole system by modeling the interactions among its pieces. Examples include biomolecules in a cell interacting to provide some primary function, or species in an environment forming a stable community. However, these interactions are often unknown; instead, the pieces' dynamic states are known, and network structure must be inferred. Because observed function may be explained by many different networks (e.g., ≈ 10(30 for the yeast cell cycle process, considering dynamics beyond this primary function means picking a single network or suitable sample: measuring over all networks exhibiting the primary function is computationally infeasible. We circumvent that obstacle by calculating the network class ensemble. We represent the ensemble by a stochastic matrix T, which is a transition-by-transition superposition of the system dynamics for each member of the class. We present concrete results for T derived from boolean time series dynamics on networks obeying the Strong Inhibition rule, by applying T to several traditional questions about network dynamics. We show that the distribution of the number of point attractors can be accurately estimated with T. We show how to generate Derrida plots based on T. We show that T-based Shannon entropy outperforms other methods at selecting experiments to further narrow the network structure. We also outline an experimental test of predictions based on T. We motivate all of these results in terms of a popular molecular biology boolean network model for the yeast cell cycle, but the methods and analyses we introduce are general. We conclude with open questions for T, for example, application to other models, computational considerations when scaling up to larger systems, and other potential analyses.

  2. Complex conductivity of soils

    NARCIS (Netherlands)

    Revil, A.; Coperey, A.; Shao, Z.; Florsch, N.; Fabricus, I.L.; Deng, Y.; Delsman, J.R.; Pauw, P.S.; Karaoulis, M.; Louw, P.G.B. de; Baaren, E.S. van; Dabekaussen, W.; Menkovic, A.; Gunnink, J.L.

    2017-01-01

    The complex conductivity of soils remains poorly known despite the growing importance of this method in hydrogeophysics. In order to fill this gap of knowledge, we investigate the complex conductivity of 71 soils samples (including four peat samples) and one clean sand in the frequency range 0.1 Hz

  3. Conducting polymer hydrogels

    Czech Academy of Sciences Publication Activity Database

    Stejskal, Jaroslav

    2017-01-01

    Roč. 71, č. 2 (2017), s. 269-291 ISSN 0366-6352 R&D Projects: GA ČR(CZ) GA16-02787S Institutional support: RVO:61389013 Keywords : aerogel * conducting polymers * conductivity Subject RIV: CD - Macromolecular Chemistry OBOR OECD: Polymer science Impact factor: 1.258, year: 2016

  4. Conductivities from attractors

    Energy Technology Data Exchange (ETDEWEB)

    Erdmenger, Johanna [Max-Planck-Institut für Physik (Werner-Heisenberg-Institut), Föhringer Ring 6, D-80805 Munich (Germany); Institut für Theoretische Physik und Astrophysik, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg (Germany); Fernández, Daniel [Max-Planck-Institut für Physik (Werner-Heisenberg-Institut), Föhringer Ring 6, D-80805 Munich (Germany); Science Institute, University of Iceland, Dunhaga 3, 107 Reykjavík (Iceland); Goulart, Prieslei [Max-Planck-Institut für Physik (Werner-Heisenberg-Institut), Föhringer Ring 6, D-80805 Munich (Germany); Instituto de Física Teórica, UNESP-Universidade Estadual Paulista,R. Dr. Bento T. Ferraz 271, Bl. II, São Paulo 01140-070, SP (Brazil); Witkowski, Piotr [Max-Planck-Institut für Physik (Werner-Heisenberg-Institut), Föhringer Ring 6, D-80805 Munich (Germany)

    2017-03-28

    In the context of applications of the AdS/CFT correspondence to condensed matter physics, we compute conductivities for field theory duals of dyonic planar black holes in 3+1-dimensional Einstein-Maxwell-dilaton theories at zero temperature. We combine the near-horizon data obtained via Sen’s entropy function formalism with known expressions for conductivities. In this way we express the conductivities in terms of the extremal black hole charges. We apply our approach to three different examples for dilaton theories for which the background geometry is not known explicitly. For a constant scalar potential, the thermoelectric conductivity explicitly scales as α{sub xy}∼N{sup 3/2}, as expected. For the same model, our approach yields a finite result for the heat conductivity κ/T∝N{sup 3/2} even for T→0.

  5. Thermal conductivity of technetium

    International Nuclear Information System (INIS)

    Minato, K.; Serizawa, H.; Fukuda, K.

    1998-01-01

    The thermal diffusivity of technetium was measured on a disk sample of 5 mm in diameter and 1 mm in thickness by the laser flash method from room temperature to 1173 K, and the thermal conductivity was determined by the measured thermal diffusivity and density, and the reported specific heat capacity. The thermal diffusivity of technetium decreases with increasing temperature though it is almost constant above 600 K. The thermal conductivity of technetium shows a minimum around 400 K, above which the thermal conductivity increases with temperature. The electronic and phonon components of the thermal conductivity were evaluated approximately. The increase in the thermal conductivity of technetium with temperature is due to the increase in the electronic component. (orig.)

  6. Seismic fragility analyses

    International Nuclear Information System (INIS)

    Kostov, Marin

    2000-01-01

    In the last two decades there is increasing number of probabilistic seismic risk assessments performed. The basic ideas of the procedure for performing a Probabilistic Safety Analysis (PSA) of critical structures (NUREG/CR-2300, 1983) could be used also for normal industrial and residential buildings, dams or other structures. The general formulation of the risk assessment procedure applied in this investigation is presented in Franzini, et al., 1984. The probability of failure of a structure for an expected lifetime (for example 50 years) can be obtained from the annual frequency of failure, β E determined by the relation: β E ∫[d[β(x)]/dx]P(flx)dx. β(x) is the annual frequency of exceedance of load level x (for example, the variable x may be peak ground acceleration), P(fI x) is the conditional probability of structure failure at a given seismic load level x. The problem leads to the assessment of the seismic hazard β(x) and the fragility P(fl x). The seismic hazard curves are obtained by the probabilistic seismic hazard analysis. The fragility curves are obtained after the response of the structure is defined as probabilistic and its capacity and the associated uncertainties are assessed. Finally the fragility curves are combined with the seismic loading to estimate the frequency of failure for each critical scenario. The frequency of failure due to seismic event is presented by the scenario with the highest frequency. The tools usually applied for probabilistic safety analyses of critical structures could relatively easily be adopted to ordinary structures. The key problems are the seismic hazard definitions and the fragility analyses. The fragility could be derived either based on scaling procedures or on the base of generation. Both approaches have been presented in the paper. After the seismic risk (in terms of failure probability) is assessed there are several approaches for risk reduction. Generally the methods could be classified in two groups. The

  7. Ionic conducting poly-benzimidazoles

    International Nuclear Information System (INIS)

    Jouanneau, J.

    2006-11-01

    Over the last years, many research works have been focused on new clean energy systems. Hydrogen fuel cell seems to be the most promising one. However, the large scale development of this technology is still limited by some key elements. One of them is the polymer electrolyte membrane 'Nafion' currently used, for which the ratio performance/cost is too low. The investigations we carried out during this thesis work are related to a new class of ionic conducting polymer, the sulfonated poly-benzimidazoles (sPBI). Poly-benzimidazoles (PBI) are aromatic heterocyclic polymers well-known for their excellent thermal and chemical stability. Ionic conduction properties are obtained by having strong acid groups (sulfonic acid SO 3 H) on the macromolecular structure. For that purpose, we first synthesized sulfonated monomers. Their poly-condensation with an appropriate non-sulfonated co-monomer yields to sPBI with sulfonation range from 0 to 100 per cent. Three different sPBI structures were obtained, and verified by appropriate analytical techniques. We also showed that the protocol used for the synthesis resulted in high molecular weights polymers. We prepared ionic conducting membrane by casting sPBI solutions on glass plates. Their properties of stability, water swelling and ionic conductivity were investigated. Surprisingly, the behaviour of sPBI was quite different from the other sulfonated aromatic polymers with same amount of SO 3 H, their stability was much higher, but their water swelling and ionic conductivity were quite low. We attributed these differences to strong ionic interactions between the sulfonic acid groups and the basic benzimidazole groups of our polymers. However, we managed to solve this problem synthesizing very highly sulfonated PBI, obtaining membranes with a good balance between all the properties necessary. (author)

  8. Website-analyse

    DEFF Research Database (Denmark)

    Thorlacius, Lisbeth

    2009-01-01

    eller blindgyder, når han/hun besøger sitet. Studier i design og analyse af de visuelle og æstetiske aspekter i planlægning og brug af websites har imidlertid kun i et begrænset omfang været under reflektorisk behandling. Det er baggrunden for dette kapitel, som indleder med en gennemgang af æstetikkens......Websitet er i stigende grad det foretrukne medie inden for informationssøgning,virksomhedspræsentation, e-handel, underholdning, undervisning og social kontakt. I takt med denne voksende mangfoldighed af kommunikationsaktiviteter på nettet, er der kommet mere fokus på at optimere design og...... planlægning af de funktionelle og indholdsmæssige aspekter ved websites. Der findes en stor mængde teori- og metodebøger, som har specialiseret sig i de tekniske problemstillinger i forbindelse med interaktion og navigation, samt det sproglige indhold på websites. Den danske HCI (Human Computer Interaction...

  9. A channel profile analyser

    International Nuclear Information System (INIS)

    Gobbur, S.G.

    1983-01-01

    It is well understood that due to the wide band noise present in a nuclear analog-to-digital converter, events at the boundaries of adjacent channels are shared. It is a difficult and laborious process to exactly find out the shape of the channels at the boundaries. A simple scheme has been developed for the direct display of channel shape of any type of ADC on a cathode ray oscilliscope display. This has been accomplished by sequentially incrementing the reference voltage of a precision pulse generator by a fraction of a channel and storing ADC data in alternative memory locations of a multichannel pulse height analyser. Alternative channels are needed due to the sharing at the boundaries of channels. In the flat region of the profile alternate memory locations are channels with zero counts and channels with the full scale counts. At the boundaries all memory locations will have counts. The shape of this is a direct display of the channel boundaries. (orig.)

  10. Chemical Emergencies - Multiple Languages

    Science.gov (United States)

    ... Chemical Emergencies - bosanski (Bosnian) PDF Chemical Emergencies - English MP3 Chemical Emergencies - bosanski (Bosnian) MP3 Chemical Emergencies - English MP4 Chemical Emergencies - bosanski (Bosnian) ...

  11. Fatty acid composition and its association with chemical and sensory analysis of boar taint.

    Science.gov (United States)

    Liu, Xiaoye; Trautmann, Johanna; Wigger, Ruth; Zhou, Guanghong; Mörlein, Daniel

    2017-09-15

    A certain level of disagreement between the chemical analysis of androstenone and skatole and the human perception of boar taint has been found in many studies. Here we analyze whether the fatty acid composition can explain such inconsistency between sensory evaluation and chemical analysis of boar taint compounds. Therefore, back fat samples (n=143) were selected according to their sensory evaluation by a 10-person sensory panel, and the chemical analysis (stable isotope dilution analysis with headspace solid-phase microextraction and gas chromatography-mass spectrometry) of androstenone and skatole. Subsequently a quantification of fatty acids using gas chromatography-flame ionization detection was conducted. The correlation analyses revealed that several fatty acids are significantly correlated with androstenone, skatole, and the sensory rating. However, multivariate analyses (principal component analysis) revealed no explanation of the fatty acid composition with respect to the (dis-)agreement between sensory and chemical analysis. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. Measurement of thermal conductance

    International Nuclear Information System (INIS)

    Kuchnir, M.

    1977-01-01

    The 6-m long, 45-kG, warm-iron superconducting magnets envisioned for the Energy Doubler stage of the Fermilab accelerator require stiff supports with minimized thermal conductances in order to keep the refrigeration power reasonable. The large number of supports involved in the system required a careful study of their heat conduction from the room temperature wall to the intercepting refrigeration at 20 0 K and to the liquid helium. For this purpose the thermal conductance of this support was measured by comparing it with the thermal conductance of a copper strap of known geometry. An association of steady-state thermal analysis and experimental thermal conductivity techniques forms the basis of this method. An important advantage is the automatic simulation of the 20 0 K refrigeration intercept by the copper strap, which simplifies the apparatus considerably. This relative resistance technique, which uses electrical analogy as a guideline, is applicable with no restrictions for materials with temperature-independent thermal conductivity. For other materials the results obtained are functions of the specific temperature interval involved in the measurements. A comprehensive review of the literature on thermal conductivity indicates that this approach has not been used before. A demonstration of its self-consistency is stressed here rather than results obtained for different supports

  13. Conductive polymeric compositions for lithium batteries

    Science.gov (United States)

    Angell, Charles A [Mesa, AZ; Xu, Wu [Tempe, AZ

    2009-03-17

    Novel chain polymers comprising weakly basic anionic moieties chemically bound into a polyether backbone at controllable anionic separations are presented. Preferred polymers comprise orthoborate anions capped with dibasic acid residues, preferably oxalato or malonato acid residues. The conductivity of these polymers is found to be high relative to that of most conventional salt-in-polymer electrolytes. The conductivity at high temperatures and wide electrochemical window make these materials especially suitable as electrolytes for rechargeable lithium batteries.

  14. Multivalent ion conducting solids

    Energy Technology Data Exchange (ETDEWEB)

    Imanaka, N. [Osaka Univ., Suita, Osaka (Japan). Dept. of Applied Chemistry

    2008-07-01

    Solid electrolytes possess important characteristics for industrial applications. Only a single ionic species can macroscopically migrate in these solids. This paper described a the new NASICON (M-Zr-Nb-P-O) type system, exhibiting an exceptionally high level of trivalent M3+ ion conductivity on polycrystalline solids. The partial substitution of the smaller higher valent Nb5+ ion for Zr4+ stabilized the NASICON phase and realized the M3+ ion conduction in the NASICON structure. It was concluded that the conductivities of the series are comparable to those of the practically applied solid electrolytes of oxide anion conductors of YSZ and CSZ. 3 refs., 2 figs.

  15. Conducting everyday life

    DEFF Research Database (Denmark)

    Juhl, Pernille

    , they are involved in preventive interventions. I conducted participatory observations with the children in their everyday life. Overall, the study stresses that even small children must be perceived as active participants who act upon and struggle with different conditions and meaning making processes across......In the paper I discuss how small children (0-4 year) develop through ‘conducting everyday life’ across contexts (Holzkamp 2013). I discuss how this process of conducting everyday life is essential when discussing the ‘good life for children’ from a child perspective. These issues are addressed...... contexts (home, day care, part-time foster family) and in relation to other co-participants....

  16. Uranium favorability of tertiary sedimentary rocks of the western Okanogan highlands and of the upper Columbia River valley, Washington. [Measurement and sampling of surface sections, collection of samples from isolated outcrops, and chemical and mineralogical analyses of samples; no known uranium deposits

    Energy Technology Data Exchange (ETDEWEB)

    Marjaniemi, D.K.; Robins, J.W.

    1975-08-01

    Tertiary sedimentary rocks in the northern portions of the western Okanogan highlands and in the upper Columbia River valley were investigated during a regional study to determine the favorability for potential uranium resources of the Tertiary sedimentary rocks of northeastern Washington. This project involved measurement and sampling of surface sections, collection of samples from isolated outcrops, and chemical and mineralogical analyses of samples. No portion of the project area of this report is rated of high or of medium favorability for potential uranium resources. Low favorability ratings are given to Oroville, Tonasket, and Pine Creek areas of the Okanogan River valley; to the Republic graben; and to the William Lakes, Colville, and Sheep Creek areas of the upper Columbia River valley. All these areas contain some fluvial, poorly sorted feldspathic or arkosic sandstones and conglomerates. These rocks are characterized by very low permeability and a consistently high siliceous matrix suggesting very low initial permeability. There are no known uranium deposits in any of these areas, and low level uranium anomalies are rare.

  17. Electrically conductive material

    Science.gov (United States)

    Singh, J.P.; Bosak, A.L.; McPheeters, C.C.; Dees, D.W.

    1993-09-07

    An electrically conductive material is described for use in solid oxide fuel cells, electrochemical sensors for combustion exhaust, and various other applications possesses increased fracture toughness over available materials, while affording the same electrical conductivity. One embodiment of the sintered electrically conductive material consists essentially of cubic ZrO[sub 2] as a matrix and 6-19 wt. % monoclinic ZrO[sub 2] formed from particles having an average size equal to or greater than about 0.23 microns. Another embodiment of the electrically conductive material consists essentially at cubic ZrO[sub 2] as a matrix and 10-30 wt. % partially stabilized zirconia (PSZ) formed from particles having an average size of approximately 3 microns. 8 figures.

  18. Conductive open frameworks

    Science.gov (United States)

    Yaghi, Omar M.; Wan, Shun; Doonan, Christian J.; Wang, Bo; Deng, Hexiang

    2018-05-22

    The disclosure relates generally to materials that comprise conductive covalent organic frameworks. The disclosure also relates to materials that are useful to store and separate gas molecules and sensors.

  19. Sodium conducting polymer electrolytes

    Energy Technology Data Exchange (ETDEWEB)

    Skaarup, S.; West, K. (eds.)

    1989-04-01

    This section deals with the aspects of ionic conduction in general as well as specific experimental results obtained for sodium systems. The conductivity as a function of temperature and oxygen/metal ratio are given for the systems NaI, NaCF/sub 3/SO/sub 3/ and NaClO/sub 4/ plus polyethylene oxide. Attempts have been made to produce mixed phase solid electrolytes analogous to the lithium systems that have worked well. These consist of mixtures of polymer and a solid electrolyte. The addition of both nasicon and sodium beta alumina unexpectedly decreases the ionic conductivity in contrast to the lithium systems. Addition of the nonconducting silica AEROSIL in order to increase the internal surface area has the effect of retarding the phase transition at 60 deg. C, but does not enhance the conductivity. (author) 23 refs.

  20. Conductive polypropylene composites

    International Nuclear Information System (INIS)

    Koszkul, J.

    1997-01-01

    The results of studies on polypropylene composites with three sorts of Polish-made carbon blacks were presented. It was found that composite of 20% black content had properties of an electrically conducting material

  1. Complex conductivity of soils

    DEFF Research Database (Denmark)

    Revil, A.; Coperey, A.; Shao, Z.

    2017-01-01

    The complex conductivity of soil remains poorly known despite the growing importance of this method in hyrogeophysics. In order to fill this gap of knowledge, we investigate the complex conductivity of 71 soils samples (including 4 peat samples) and one clean sand in the frequency range 0.1 Hertz...... to 45 kHz. The soil samples are saturated with 6 different NaCl brines with conductivities (0.031, 0.53, 1.15, 5.7, 14.7, and 22 S m-1, NaCl, 25°C) in order to determine their intrinsic formation factor and surface conductivity. This dataset is used to test the predictions of the dynamic Stern...

  2. Hazardous Chemicals

    Centers for Disease Control (CDC) Podcasts

    2007-04-10

    Chemicals are a part of our daily lives, providing many products and modern conveniences. With more than three decades of experience, The Centers for Disease Control and Prevention (CDC) has been in the forefront of efforts to protect and assess people's exposure to environmental and hazardous chemicals. This report provides information about hazardous chemicals and useful tips on how to protect you and your family from harmful exposure.  Created: 4/10/2007 by CDC National Center for Environmental Health.   Date Released: 4/13/2007.

  3. Chemical Control of Plant Growth.

    Science.gov (United States)

    Agricultural Research Center (USDA), Beltsville, MD.

    Seven experiments are presented in this Science Study Aid to help students investigate the control of plant growth with chemicals. Plant growth regulators, weed control, and chemical pruning are the topics studied in the experiments which are based on investigations that have been and are being conducted at the U. S. Agricultural Research Center,…

  4. Conductivity studies on microwave synthesized glasses

    Indian Academy of Sciences (India)

    It has been found that conductivity in these glasses changes from the predominantly 'ionic' to predominantly 'electronic' depending upon the chemical composition. ... Indian Institute of Science, Bangalore 560012, India; Department of Physics, Sree Siddaganga College of Arts, Science and Commerce, Tumkur University, ...

  5. Chemical Peel

    Science.gov (United States)

    ... your expectations. Talk with your doctor about your motivations and expectations, as well as the potential risks. ... the sun permanently to prevent changes in skin color. Keep in mind that chemical peel results might ...

  6. Chemical carcinogens

    National Research Council Canada - National Science Library

    Searle, Charles E

    1976-01-01

    Cancer causing agents are now known to exist throughout the environment-in polluted air and tobacco smoke, in various plants and foods, and in many chemicals that are used in industry and laboratories...

  7. Quantum size effects on the thermal and potential conductivities of ideal gases

    International Nuclear Information System (INIS)

    Ozturk, Z F; Sisman, A

    2009-01-01

    Thermal and potential conductivities of ideal Maxwellian, Fermi and Bose gases are derived by considering the small corrections due to the wave character of gas particles. Potential conductivity is regarded as conductivity due to any potential gradient like electrical, gravitational or chemical ones. A long rectangular channel is considered as a transport domain. The size of the domain in the transport direction is much longer than the mean free path of particles l while the sizes in transverse directions are shorter than l. On the other hand, all sizes of the domain are assumed to be larger than the thermal de Broglie wavelength of particles. Therefore, quantum size effects (QSE) are weak enough to be considered as small corrections on conventional terms. Corrections on thermal and potential conductivities are examined. It is seen that the size and shape of the transport domain become additional control parameters on both conductivities. Since the size dependencies of thermal and electrical conductivities are different, the Lorenz number becomes size and shape dependent and deviations from the Wiedemann-Franz law may be expected in nanoscale due to QSE. Variations of the corrections with chemical potential are analysed.

  8. Electrically Conductive Epoxy Adhesives

    Directory of Open Access Journals (Sweden)

    Lan Bai

    2011-02-01

    Full Text Available Conductive adhesives are widely used in electronic packaging applications such as die attachment and solderless interconnections, component repair, display interconnections, and heat dissipation. The effects of film thickness as functions of filler volume fraction, conductive filler size, shape, as well as uncured adhesive matrix viscosity on the electrical conduction behavior of epoxy-based adhesives are presented in this work. For this purpose, epoxy-based adhesives were prepared using conductive fillers of different size, shape, and types, including Ni powder, flakes, and filaments, Ag powder, and Cu powder. The filaments were 20 μm in diameter, and 160 or 260 μm in length. HCl and H3PO4 acid solutions were used to etch and remove the surface oxide layers from the fillers. The plane resistance of filled adhesive films was measured using the four-point method. In all cases of conductive filler addition, the planar resistivity levels for the composite adhesive films increased when the film thickness was reduced. The shape of resistivity-thickness curves was negative exponential decaying type and was modeled using a mathematical relation. The relationships between the conductive film resistivities and the filler volume fractions were also derived mathematically based on the experimental data. Thus, the effects of surface treatment of filler particles, the type, size, shape of fillers, and the uncured epoxy viscosity could be included empirically by using these mathematical relations based on the experimental data. By utilizing the relations we proposed to model thickness-dependent and volume fraction-dependent conduction behaviors separately, we were able to describe the combined and coupled volume fraction-film thickness relationship mathematically based on our experimental data.

  9. Fluid conductivity sensor

    International Nuclear Information System (INIS)

    Miller, F. M.

    1985-01-01

    Apparatus for sensing the electrical conductivity of fluid which can be used to detonate an electro explosive device for operating a release mechanism for uncoupling a parachute canopy from its load upon landing in water. An operating network connected to an ignition capacitor and to a conductivity sensing circuit and connected in controlling relation to a semiconductor switch has a voltage independent portion which controls the time at which the semiconductor switch is closed to define a discharge path to detonate the electro explosive device independent of the rate of voltage rise on the ignition capacitor. The operating network also has a voltage dependent portion which when a voltage of predetermined magnitude is developed on the conductivity sensing circuit in response to fluid not having the predetermined condition of conductivity, the voltage dependent portion closes the semiconductor switch to define the discharge path when the energy level is insufficient to detonate the electro explosive device. A regulated current source is connected in relation to the conductivity sensing circuit and to the electrodes thereof in a manner placing the circuit voltage across the electrodes when the conductivity of the fluid is below a predetermined magnitude so that the sensing circuit does not respond thereto and placing the circuit voltage across the sensing circuit when the conductivity of the fluid is greater than a predetermined magnitude. The apparatus is operated from a battery, and the electrodes are of dissimilar metals so selected and connected relative to the polarity portions of the circuit to maximize utilization of the battery output voltage

  10. NOAA's National Snow Analyses

    Science.gov (United States)

    Carroll, T. R.; Cline, D. W.; Olheiser, C. M.; Rost, A. A.; Nilsson, A. O.; Fall, G. M.; Li, L.; Bovitz, C. T.

    2005-12-01

    NOAA's National Operational Hydrologic Remote Sensing Center (NOHRSC) routinely ingests all of the electronically available, real-time, ground-based, snow data; airborne snow water equivalent data; satellite areal extent of snow cover information; and numerical weather prediction (NWP) model forcings for the coterminous U.S. The NWP model forcings are physically downscaled from their native 13 km2 spatial resolution to a 1 km2 resolution for the CONUS. The downscaled NWP forcings drive an energy-and-mass-balance snow accumulation and ablation model at a 1 km2 spatial resolution and at a 1 hour temporal resolution for the country. The ground-based, airborne, and satellite snow observations are assimilated into the snow model's simulated state variables using a Newtonian nudging technique. The principle advantages of the assimilation technique are: (1) approximate balance is maintained in the snow model, (2) physical processes are easily accommodated in the model, and (3) asynoptic data are incorporated at the appropriate times. The snow model is reinitialized with the assimilated snow observations to generate a variety of snow products that combine to form NOAA's NOHRSC National Snow Analyses (NSA). The NOHRSC NSA incorporate all of the available information necessary and available to produce a "best estimate" of real-time snow cover conditions at 1 km2 spatial resolution and 1 hour temporal resolution for the country. The NOHRSC NSA consist of a variety of daily, operational, products that characterize real-time snowpack conditions including: snow water equivalent, snow depth, surface and internal snowpack temperatures, surface and blowing snow sublimation, and snowmelt for the CONUS. The products are generated and distributed in a variety of formats including: interactive maps, time-series, alphanumeric products (e.g., mean areal snow water equivalent on a hydrologic basin-by-basin basis), text and map discussions, map animations, and quantitative gridded products

  11. Low thermal conductivity skutterudites

    Energy Technology Data Exchange (ETDEWEB)

    Fleurial, J P; Caillat, T; Borshchevsky, A

    1997-07-01

    Recent experimental results on semiconductors with the skutterudite crystal structure show that these materials possess attractive transport properties and have a good potential for achieving ZT values substantially larger than for state-of-the-art thermoelectric materials. Both n-type and p-type conductivity samples have been obtained, using several preparation techniques. Associated with a low hole effective mass, very high carrier mobilities, low electrical resistivities and moderate Seebeck coefficients are obtained in p-type skutterudites. For a comparable doping level, the carrier mobilities of n-type samples are about an order of magnitude lower than the values achieved on p-type samples. However, the much larger electron effective masses and Seebeck coefficients on p-type samples. However, the much larger electron effective masses and Seebeck coefficients make n-type skutterudite promising candidates as well. Unfortunately, the thermal conductivities of the binary skutterudites compounds are too large, particularly at low temperatures, to be useful for thermoelectric applications. Several approaches to the reduction of the lattice thermal conductivity in skutterudites are being pursued: heavy doping, formation of solid solutions and alloys, study of novel ternary and filled skutterudite compounds. All those approaches have already resulted in skutterudite compositions with substantially lower thermal conductivity values in these materials. Recently, superior thermoelectric properties in the moderate to high temperature range were achieved for compositions combining alloying and filling of the skutterudite structure. Experimental results and mechanisms responsible for low thermal conductivity in skutterudites are discussed.

  12. Responsible conduct of research

    CERN Document Server

    Shamoo, Adil E

    2015-01-01

    Since the early 2000s, the field of Responsible Conduct of Research has become widely recognized as essential to scientific education, investigation, and training. At present, research institutions with public funding are expected to have some minimal training and education in RCR for their graduate students, fellows and trainees. These institutions also are expected to have a system in place for investigating and reporting misconduct in research or violations of regulations in research with human subjects, or in their applications to federal agencies for funding. Public scrutiny of the conduct of scientific researchers remains high. Media reports of misconduct scandals, biased research, violations of human research ethics rules, and moral controversies in research occur on a weekly basis. Since the 2009 publication of the 2nd edition of Shamoo and Resnik's Responsible Conduct of Research, there has been a vast expansion in the information, knowledge, methods, and diagnosis of problems related to RCR and the ...

  13. Universal conductance fluctuations in disordered metals

    International Nuclear Information System (INIS)

    Lee, P.A.

    1987-01-01

    The author argues that observed and theoretical fluctuations in the electrical conductance of disordered metals, induced by variations in the magnetic field or the chemical potential, are not time-dependent noise but that the conductance is a deterministic albeit fluctuating function for a given realization of the impurity configuration. A method is constructed for representing the sensitivity of the conductance of a given metal to a small change in the impurity configuration as a function of such variables as sample size, impurities per unit volume, and mean free path. The sensitivity helps explain the size of 1/f noise due to defect motion in disordered metals

  14. Quantized Majorana conductance

    Science.gov (United States)

    Zhang, Hao; Liu, Chun-Xiao; Gazibegovic, Sasa; Xu, Di; Logan, John A.; Wang, Guanzhong; van Loo, Nick; Bommer, Jouri D. S.; de Moor, Michiel W. A.; Car, Diana; Op Het Veld, Roy L. M.; van Veldhoven, Petrus J.; Koelling, Sebastian; Verheijen, Marcel A.; Pendharkar, Mihir; Pennachio, Daniel J.; Shojaei, Borzoyeh; Lee, Joon Sue; Palmstrøm, Chris J.; Bakkers, Erik P. A. M.; Sarma, S. Das; Kouwenhoven, Leo P.

    2018-04-01

    Majorana zero-modes—a type of localized quasiparticle—hold great promise for topological quantum computing. Tunnelling spectroscopy in electrical transport is the primary tool for identifying the presence of Majorana zero-modes, for instance as a zero-bias peak in differential conductance. The height of the Majorana zero-bias peak is predicted to be quantized at the universal conductance value of 2e2/h at zero temperature (where e is the charge of an electron and h is the Planck constant), as a direct consequence of the famous Majorana symmetry in which a particle is its own antiparticle. The Majorana symmetry protects the quantization against disorder, interactions and variations in the tunnel coupling. Previous experiments, however, have mostly shown zero-bias peaks much smaller than 2e2/h, with a recent observation of a peak height close to 2e2/h. Here we report a quantized conductance plateau at 2e2/h in the zero-bias conductance measured in indium antimonide semiconductor nanowires covered with an aluminium superconducting shell. The height of our zero-bias peak remains constant despite changing parameters such as the magnetic field and tunnel coupling, indicating that it is a quantized conductance plateau. We distinguish this quantized Majorana peak from possible non-Majorana origins by investigating its robustness to electric and magnetic fields as well as its temperature dependence. The observation of a quantized conductance plateau strongly supports the existence of Majorana zero-modes in the system, consequently paving the way for future braiding experiments that could lead to topological quantum computing.

  15. Assessing the Higher National Diploma Chemical Engineering programme in Ghana: students' perspective

    Science.gov (United States)

    Boateng, Cyril D.; Cudjoe Bensah, Edem; Ahiekpor, Julius C.

    2012-05-01

    Chemical engineers have played key roles in the growth of the chemical and allied industries in Ghana but indigenous industries that have traditionally been the domain of the informal sector need to be migrated to the formal sector through the entrepreneurship and innovation of chemical engineers. The Higher National Diploma Chemical Engineering programme is being migrated from a subject-based to a competency-based curriculum. This paper evaluates the programme from the point of view of students. Data were drawn from a survey conducted in the department and were analysed using SPSS. The survey involved administering questionnaires to students at all levels in the department. Analysis of the responses indicated that the majority of the students had decided to pursue chemical engineering due to the career opportunities available. Their knowledge of the programme learning outcomes was, however, poor. The study revealed that none of the students was interested in developing indigenous industries.

  16. Variability of chemical analysis of reinforcing bar produced in Saudi Arabia

    Science.gov (United States)

    Salman, A.; Djavanroodi, F.

    2018-04-01

    In view of the importance and demanding roles of steel rebar’s in the reinforced concrete structures, accurate information on the properties of the steels is important at the design stage. In the steelmaking process, production variations in chemical composition are unavoidable. The aim of this work is to study the variability of the chemical composition of reinforcing steel produced throughout the Saudi Arabia and asses the quality of steel rebar’s acoording to ASTM A615. 68 samples of ASTM A615 Grade 60 from different manufacturers were collected and tested using the Spectrometer test to obtain Chemical Compositions. EasyFit (5.6) software is utilized to conducted statistical analysis. Chemical compositions distributions and, control charts are generated for the compositions. Results showed that some compositions are above the upper line of the control chart. Finally, the analyses show that less than 3% of the steel failed to meet minimum ASTM standards for chemical composition.

  17. Interpenetrating networks of two conducting polymers

    DEFF Research Database (Denmark)

    Winther-Jensen, Bjørn; West, Keld

    2005-01-01

    Interpenetrating networks (IPNs) of two conjugated polymers are prepared by a combination of a chemical oxidation step and a vapour phase polymerisation step on non-conducting surfaces. In this work ferric tosylate was used as the oxidant as it gives very smooth and homogeneous coatings, and beca......Interpenetrating networks (IPNs) of two conjugated polymers are prepared by a combination of a chemical oxidation step and a vapour phase polymerisation step on non-conducting surfaces. In this work ferric tosylate was used as the oxidant as it gives very smooth and homogeneous coatings......, and because its reaction products can be removed efficiently after the formation of the composite. Several combinations of polymers are demonstrated, and the versatility of the proposed method allows extensions to a wide range of conjugated polymers. The IPNs show optical and electrochemical characteristics......, which are sums of the characteristics from the participating conducting polymers....

  18. Conducting Educational Design Research

    Science.gov (United States)

    McKenney, Susan; Reeves, Thomas

    2012-01-01

    Educational design research blends scientific investigation with systematic development and implementation of solutions to educational problems. Empirical investigation is conducted in real learning settings--not laboratories--to craft usable and effective solutions. At the same time, the research is carefully structured to produce theoretical…

  19. Conductance eigenchannels in nanocontacts

    DEFF Research Database (Denmark)

    Brandbyge, Mads; Sørensen, Mads Reinholdt; Jacobsen, Karsten Wedel

    1997-01-01

    The electronic conductance of metal nanocontacts is analyzed in terms of eigenchannels for the transmission. The transmission through individual eigenchannels is calculated numerically for realistic models of gold point contacts based on molecular-dynamics simulation of the elongation of a contac...

  20. Conduct Disorder and Comorbidity.

    Science.gov (United States)

    Stahl, Nicole D.; Clarizio, Harvey F.

    1999-01-01

    Provides critical examination of research published during past ten years addressing Conduct Disorder (CD), Attention Deficit Hyperactivity Disorder, Oppositional Defiant Disorder (ODD), and internalizing disorders. Concludes comorbidity varies with age, gender, informant, diagnostic criteria, and nature of the sample. Implications of comorbidity…

  1. CERN Code of Conduct

    CERN Document Server

    Department, HR

    2010-01-01

    The Code is intended as a guide in helping us, as CERN contributors, to understand how to conduct ourselves, treat others and expect to be treated. It is based around the five core values of the Organization. We should all become familiar with it and try to incorporate it into our daily life at CERN.

  2. High Thermal Conductivity Materials

    CERN Document Server

    Shinde, Subhash L

    2006-01-01

    Thermal management has become a ‘hot’ field in recent years due to a need to obtain high performance levels in many devices used in such diverse areas as space science, mainframe and desktop computers, optoelectronics and even Formula One racing cars! Thermal solutions require not just taking care of very high thermal flux, but also ‘hot spots’, where the flux densities can exceed 200 W/cm2. High thermal conductivity materials play an important role in addressing thermal management issues. This volume provides readers a basic understanding of the thermal conduction mechanisms in these materials and discusses how the thermal conductivity may be related to their crystal structures as well as microstructures developed as a result of their processing history. The techniques for accurate measurement of these properties on large as well as small scales have been reviewed. Detailed information on the thermal conductivity of diverse materials including aluminum nitride (AlN), silicon carbide (SiC), diamond, a...

  3. Transient Heat Conduction

    DEFF Research Database (Denmark)

    Rode, Carsten

    1998-01-01

    Analytical theory of transient heat conduction.Fourier's law. General heat conducation equation. Thermal diffusivity. Biot and Fourier numbers. Lumped analysis and time constant. Semi-infinite body: fixed surface temperature, convective heat transfer at the surface, or constant surface heat flux...

  4. Pressure dependence of conductivity

    International Nuclear Information System (INIS)

    Bracewell, B.L.; Hochheimer, H.D.

    1993-01-01

    The overall objectives of this work were to attempt the following: (1) Measure the pressure dependence of the electrical conductivity of several quasi-one-dimensional, charge-density-wave solids, including measurements along various crystal directions. (2) Measure photocurrents in selected MX solids at ambient and elevated pressures. (3) Measure the resonance Raman spectra for selected MX solids as a function of pressure

  5. New code of conduct

    CERN Multimedia

    Laëtitia Pedroso

    2010-01-01

    During his talk to the staff at the beginning of the year, the Director-General mentioned that a new code of conduct was being drawn up. What exactly is it and what is its purpose? Anne-Sylvie Catherin, Head of the Human Resources (HR) Department, talked to us about the whys and wherefores of the project.   Drawing by Georges Boixader from the cartoon strip “The World of Particles” by Brian Southworth. A code of conduct is a general framework laying down the behaviour expected of all members of an organisation's personnel. “CERN is one of the very few international organisations that don’t yet have one", explains Anne-Sylvie Catherin. “We have been thinking about introducing a code of conduct for a long time but lacked the necessary resources until now”. The call for a code of conduct has come from different sources within the Laboratory. “The Equal Opportunities Advisory Panel (read also the "Equal opportuni...

  6. Quantized Majorana conductance

    NARCIS (Netherlands)

    Zhang, Hao; Liu, Chun Xiao; Gazibegovic, Sasa; Xu, Di; Logan, John A.; Wang, Guanzhong; Van Loo, Nick; Bommer, Jouri D.S.; De Moor, Michiel W.A.; Car, Diana; Op Het Veld, Roy L.M.; Van Veldhoven, Petrus J.; Koelling, Sebastian; Verheijen, Marcel A.; Pendharkar, Mihir; Pennachio, Daniel J.; Shojaei, Borzoyeh; Lee, Joon Sue; Palmstrøm, Chris J.; Bakkers, Erik P.A.M.; Sarma, S. Das; Kouwenhoven, Leo P.

    2018-01-01

    Majorana zero-modes - a type of localized quasiparticle - hold great promise for topological quantum computing. Tunnelling spectroscopy in electrical transport is the primary tool for identifying the presence of Majorana zero-modes, for instance as a zero-bias peak in differential conductance. The

  7. Conductive polymer composition

    NARCIS (Netherlands)

    2010-01-01

    The present invention relates to a process for the preparation of a conductive polymer composition comprising graphene and the articles obtained by this process. The process comprises the following steps: A) contacting graphite oxide in an aqueous medium with a water-soluble or dispersible

  8. Thermal conductivity of REIn3 compounds

    International Nuclear Information System (INIS)

    Mucha, J

    2006-01-01

    The results of measurements of the thermal conductivity of REIn 3 (RE Pr, Nd, Dy, Ho, Tm) compounds as a function of the temperature in the interval 4-300 K in the absence and in the presence of an external magnetic field of 8 T are presented. Except for PRIn 3 all the compounds are antiferromagnetic. YIn 3 was also measured as a reference compound. The results were analysed in the paramagnetic phase, where an influence of the crystalline electric field on the thermal conductivity was found. Drastic changes in the thermal conductivity were observed and analysed in the vicinity of the Neel temperature and in the antiferromagnetic phases of the compounds. Below the Neel temperature an additional magnon contribution to the thermal conductivity was separated out

  9. Information filtering via biased heat conduction

    Science.gov (United States)

    Liu, Jian-Guo; Zhou, Tao; Guo, Qiang

    2011-09-01

    The process of heat conduction has recently found application in personalized recommendation [Zhou , Proc. Natl. Acad. Sci. USA PNASA60027-842410.1073/pnas.1000488107107, 4511 (2010)], which is of high diversity but low accuracy. By decreasing the temperatures of small-degree objects, we present an improved algorithm, called biased heat conduction, which could simultaneously enhance the accuracy and diversity. Extensive experimental analyses demonstrate that the accuracy on MovieLens, Netflix, and Delicious datasets could be improved by 43.5%, 55.4% and 19.2%, respectively, compared with the standard heat conduction algorithm and also the diversity is increased or approximately unchanged. Further statistical analyses suggest that the present algorithm could simultaneously identify users' mainstream and special tastes, resulting in better performance than the standard heat conduction algorithm. This work provides a creditable way for highly efficient information filtering.

  10. P -type transparent conducting oxides

    International Nuclear Information System (INIS)

    Zhang, Kelvin H L; Xi, Kai; Blamire, Mark G; Egdell, Russell G

    2016-01-01

    Transparent conducting oxides constitute a unique class of materials combining properties of electrical conductivity and optical transparency in a single material. They are needed for a wide range of applications including solar cells, flat panel displays, touch screens, light emitting diodes and transparent electronics. Most of the commercially available TCOs are n -type, such as Sn doped In 2 O 3 , Al doped ZnO, and F doped SnO 2 . However, the development of efficient p -type TCOs remains an outstanding challenge. This challenge is thought to be due to the localized nature of the O 2 p derived valence band which leads to difficulty in introducing shallow acceptors and large hole effective masses. In 1997 Hosono and co-workers (1997 Nature 389 939) proposed the concept of ‘chemical modulation of the valence band’ to mitigate this problem using hybridization of O 2 p orbitals with close-shell Cu 3 d 10 orbitals. This work has sparked tremendous interest in designing p -TCO materials together with deep understanding the underlying materials physics. In this article, we will provide a comprehensive review on traditional and recently emergent p -TCOs, including Cu + -based delafossites, layered oxychalcogenides, nd 6 spinel oxides, Cr 3+ -based oxides (3 d 3 ) and post-transition metal oxides with lone pair state (ns 2 ). We will focus our discussions on the basic materials physics of these materials in terms of electronic structures, doping and defect properties for p -type conductivity and optical properties. Device applications based on p -TCOs for transparent p – n junctions will also be briefly discussed. (topical review)

  11. Nanostructured conductive polymeric materials

    Science.gov (United States)

    Al-Saleh, Mohammed H.

    Conductive polymer composites (CPCs) are a suitable alternative to metals in many applications due to their light-weight, corrosion resistance, low cost, ease of processing and design flexibility. CPCs have been formulated using different types of conductive fillers. In this PhD thesis, the focus is on CPCs for electrostatic discharge (ESD) protection and electromagnetic interference (EMI) attenuation. Despite the versatility of conductive fillers, carbon black (CB) has been the dominant filler to make CPCs for ESD protection applications because CB/polymer composites have a cost advantage over all other CPCs. For EMI shielding, stainless steel fibres and metal coated fibers are the preferred fillers, however CPCs made of those fibers are not the dominant EMI shielding materials. Metal coated and polymer plated polymers are the most widely used EMI shielding options. The limited use of CPCs in the EMI shielding market is because the high filler loading required to formulate a composite with an adequate level of shielding remarkably increases the composite price. In order to increase the competitiveness of CPCs, percolation threshold should be minimized as much as possible and composites with high EMI shielding capabilities at low filler loading should be formulated because all conductive fillers are expensive compared to polymers. In this thesis, two different methodologies to reduce percolation threshold in CPCs have been successfully developed and a CPC with exceptional EMI shielding capability has been formulated using copper nanowires as conductive filler. The first percolation threshold reduction technique is based on the selective localization of CB at the interface of immiscible polymer blend. The technique requires adding a copolymer that prefers the blend's interface and for which CB nanoparticles has the highest affinity. The second method is based on producing a CPC powder and then using this powder as a conductive filler to produce composite by dry

  12. CONDUCTIVE CHANNEL FOR ENERGY TRANSMISSION

    Directory of Open Access Journals (Sweden)

    V. V. Apollonov

    2014-01-01

    Full Text Available Laser spark obtained by using a conical optics is much more appropriate to form conducting channels in atmosphere. Only two types of lasers are actively considered to be used in forming high-conductivity channels in atmosphere, controlled by laser spark: pulsed sub-microsecond gas and chemical lasers (CO2, DF and short pulse solid-state and UV lasers. Main advantage of short pulse lasers is their ability in forming of super long ionized channels with a characteristic diameter of ~100  µ  in atmosphere along the  beam propagation direction. At estimated electron densities below  10 ⋅ 16 cm–3 in these filaments and laser wavelengths in the range of 0,5–1,0 mm, the plasma barely absorbs laser radiation.  In this case, the length of the track composed of many filaments is determined by the laser intensity and may reach many kilometers at a femtosecond pulse energy of ~100 mJ. However, these lasers could not be used to form high-conductivity long channels in atmosphere. The ohmic resistance of this type a conducting channels turned out to be very high, and the gas in the channels could not be strongly heated (< 1 J. An electric breakdown controlled by radiation of femtosecond solid-state laser was implemented in only at a length of 3 m with a voltage of 2 MV across the discharge gap (670 kV/m.Not so long ago scientific group from P. N. Lebedev has improved that result, the discharge gap – 1 m had been broken under KrF laser irradiation when switching high-voltage (up to 390 kV/m electric discharge by 100-ns UV pulses. Our previous result  –  16 m long conducting channel controlled by a  laser spark at the voltage  –  3 MV  – was obtained more than 20 years ago in Russia and Japan by using pulsed CO2  laser with energy  –  0,5 kJ. An average electric field strength  was < 190 kV/m. It is still too much for efficient applications.

  13. Transparent Conductive Nanostructures

    Energy Technology Data Exchange (ETDEWEB)

    None

    2008-06-22

    The objectives of this program between UT-Battelle, LLC (the ''Contractor'') and (Battelle Memorial Institute) (the "Participant") were directed towards achieving significant improvement: in the electrical conductivity and optical/infrared transmission of single-wall carbon nanotube (SWNT)-based composite materials. These materials will be used in coating applications that range from aircraft canopies to display applications. The goal of the project was to obtain supported mats of SWNTs with sheet conductivities approaching 10 ohms/square combined with high optical transmission (>85% transmission at 550 nm), thereby permitting their application as a replacement for indium tin oxide (ITO) in a variety of applications such as flexible displays.

  14. Super ionic conductive glass

    Science.gov (United States)

    Susman, S.; Volin, K.J.

    Described is an ionically conducting glass for use as a solid electrolyte in a power or secondary cell containing an alkali metal-containing anode and a cathode separated by an alkali metal ion conducting glass having an ionic transference number of unity and the general formula: A/sub 1 + x/D/sub 2-x/3/Si/sub x/P/sub 3 - x/O/sub 12 - 2x/3/, wherein A is a network modifier for the glass and is an alkali metal of the anode, D is an intermediate for the glass and is selected from the class consisting of Zr, Ti, Ge, Al, Sb, Be, and Zn and X is in the range of from 2.25 to 3.0. Of the alkali metals, Na and Li are preferred and of the intermediate, Zr, Ti and Ge are preferred.

  15. 'Stuffed' conducting polymers

    DEFF Research Database (Denmark)

    Winther-Jensen, Bjørn; Chen, Jun; West, Keld

    2005-01-01

    Conducting polymers (CP) obtained by oxidative polymerization using iron(III) salts shrink when Fe(II) and the excess counter ions are washed out after polymerization. This phenomenon can be used to incorporate active molecules into the CP matrix via their addition to the wash liquid. In the pres......Conducting polymers (CP) obtained by oxidative polymerization using iron(III) salts shrink when Fe(II) and the excess counter ions are washed out after polymerization. This phenomenon can be used to incorporate active molecules into the CP matrix via their addition to the wash liquid....... In the present work we demonstrate this principle on three different CP's: polypyrrole (PPy), poly-terthiophene (PTTh) and poly(3,4-ethylenedioxy thiophene) (PEDT), using ferrocene as a model molecule to be trapped in the polymer films. (c) 2005 Elsevier Ltd. All rights reserved....

  16. Conducting interactive experiments online.

    Science.gov (United States)

    Arechar, Antonio A; Gächter, Simon; Molleman, Lucas

    2018-01-01

    Online labor markets provide new opportunities for behavioral research, but conducting economic experiments online raises important methodological challenges. This particularly holds for interactive designs. In this paper, we provide a methodological discussion of the similarities and differences between interactive experiments conducted in the laboratory and online. To this end, we conduct a repeated public goods experiment with and without punishment using samples from the laboratory and the online platform Amazon Mechanical Turk. We chose to replicate this experiment because it is long and logistically complex. It therefore provides a good case study for discussing the methodological and practical challenges of online interactive experimentation. We find that basic behavioral patterns of cooperation and punishment in the laboratory are replicable online. The most important challenge of online interactive experiments is participant dropout. We discuss measures for reducing dropout and show that, for our case study, dropouts are exogenous to the experiment. We conclude that data quality for interactive experiments via the Internet is adequate and reliable, making online interactive experimentation a potentially valuable complement to laboratory studies.

  17. Chemical pneumonitis

    Science.gov (United States)

    ... cleaning materials such as chlorine bleach, during industrial accidents, or near swimming pools) Grain and fertilizer dust ... and the A.D.A.M. Editorial team. Chemical Emergencies ... about A.D.A.M.'s editorial policy , editorial process and privacy policy . A.D.A.M. is ...

  18. Chemical dispersants

    NARCIS (Netherlands)

    Rahsepar, Shokouhalsadat; Smit, Martijn P.J.; Murk, Albertinka J.; Rijnaarts, Huub H.M.; Langenhoff, Alette A.M.

    2016-01-01

    Chemical dispersants were used in response to the Deepwater Horizon oil spill in the Gulf of Mexico, both at the sea surface and the wellhead. Their effect on oil biodegradation is unclear, as studies showed both inhibition and enhancement. This study addresses the effect of Corexit on oil

  19. An evaluation of soluble cations and anions on the conductivity and rate of flocculation of kaolins

    Science.gov (United States)

    Fulton, Deborah Lee

    1998-10-01

    The focus of this project was to learn how ionic concentrations and their contributions to electric conductivity influence the flocculation behavior of kaolin/water suspensions. Sodium silicate, calcium chloride, and magnesium sulfate were used as chemical additives. The specific surface areas, particle size distributions, and methylene blue indices for two kaolins were measured. The SSA and MBI for these kaolins indicated that they possessed inherent differences in SSA and flocculation behaviors. Rheological studies were also performed. Testing included simultaneous gelation, deflocculation, and pH tests. Viscosity, pH, temperature, and chemical additive concentrations were monitored at each point. Testing was performed at 45/55 wt% solids. Effects of additions of various levels of deflocculant and flocculant to each of the kaolin/water suspensions were studied by making several suspensions from each kaolin. The concentrations of dispersant, and flocculant levels and types were varied to produce suspensions with different chemical additive "histories," but all with similar final apparent viscosities. Slurry filtrates were analyzed for conductivity, pH, temperature, and ion concentrations of (Al3+, Fe2+,3+, Ca 2+, Mg+, Na+, SO4 2--, and Cl--). Plastic properties were calculated to determine how variations in suspension histories affected conductivities, pH, and detectable ion contents of the suspensions. These analyses were performed on starting slurries which were under-, completely-, and over-deflocculated before further additions of flocculants and deflocculant were added to tune the slurries to the final, constant, target viscosity. Results showed that rates of flocculation and conductivities increased as concentrations of ions increased. By increasing conductivity correlations with increases in flocculation occurs, which yields higher rates of buildup, or RBU [1]. This is the single most important slip control property in the whitewares industry. Shear

  20. Soil analyses by ICP-MS (Review)

    International Nuclear Information System (INIS)

    Yamasaki, Shin-ichi

    2000-01-01

    Soil analyses by inductively coupled plasma mass spectrometry (ICP-MS) are reviewed. The first half of the paper is devoted to the development of techniques applicable to soil analyses, where diverse analytical parameters are carefully evaluated. However, the choice of soil samples is somewhat arbitrary, and only a limited number of samples (mostly reference materials) are examined. In the second half, efforts are mostly concentrated on the introduction of reports, where a large number of samples and/or very precious samples have been analyzed. Although the analytical techniques used in these reports are not necessarily novel, valuable information concerning such topics as background levels of elements in soils, chemical forms of elements in soils and behavior of elements in soil ecosystems and the environment can be obtained. The major topics discussed are total elemental analysis, analysis of radionuclides with long half-lives, speciation, leaching techniques, and isotope ratio measurements. (author)

  1. Sorption analyses in materials science: selected oxides

    International Nuclear Information System (INIS)

    Fuller, E.L. Jr.; Condon, J.B.; Eager, M.H.; Jones, L.L.

    1981-01-01

    Physical adsorption studies have been shown to be extremely valuable in studying the chemistry and structure of dispersed materials. Many processes rely on the access to the large amount of surface made available by the high degree of dispersion. Conversely, there are many applications where consolidation of the dispersed solids is required. Several systems (silica gel, alumina catalysts, mineralogic alumino-silicates, and yttrium oxide plasters) have been studied to show the type and amount of chemical and structural information that can be obtained. Some review of current theories is given and additional concepts are developed based on statistical and thermodynamic arguments. The results are applied to sorption data to show that detailed sorption analyses are extremely useful and can provide valuable information that is difficult to obtain by any other means. Considerable emphasis has been placed on data analyses and interpretation of a nonclassical nature to show the potential of such studies that is often not recognized nor utilized

  2. Thermal contact conductance

    CERN Document Server

    Madhusudana, Chakravarti V

    2013-01-01

    The work covers both theoretical and practical aspects of thermal contact conductance. The theoretical discussion focuses on heat transfer through spots, joints, and surfaces, as well as the role of interstitial materials (both planned and inadvertent). The practical discussion includes formulae and data that can be used in designing heat-transfer equipment for a variety of joints, including special geometries and configurations. All of the material has been updated to reflect the latest advances in the field.

  3. Hysteresis in conducting ferromagnets

    International Nuclear Information System (INIS)

    Schneider, Carl S.; Winchell, Stephen D.

    2006-01-01

    Maxwell's magnetic diffusion equation is solved for conducting ferromagnetic cylinders to predict a magnetic wave velocity, a time delay for flux penetration and an eddy current field, one of five fields in the linear unified field model of hysteresis. Measured Faraday voltages for a thin steel toroid are shown to be proportional to magnetic field step amplitude and decrease exponentially in time due to maximum rather than average permeability. Dynamic permeabilities are a field convolution of quasistatic permeability and the delay function from which we derive and observe square root dependence of coercivity on rate of field change

  4. Thermal and stress analyses with ANSYS program

    International Nuclear Information System (INIS)

    Kanoo, Iwao; Kawaguchi, Osamu; Asakura, Junichi.

    1975-03-01

    Some analyses of the heat conduction and elastic/inelastic stresses, carried out in Power Reactor and Nuclear Fuel Development Corporation (PNC) in fiscal 1973 using ANSYS (Engineering Analysis System) program, are summarized. In chapter I, the present state of structural analysis programs available for a FBR (fast breeder reactor) in PNC is explained. Chapter II is a brief description of the ANSYS current status. In chapter III are presented 8 examples of the steady-state and transient thermal analyses for fast-reactor plant components, and in chapter IV 5 examples of the inelastic structural analysis. With the advance in the field of finite element method, its applications in design study should extend progressively in the future. The present report, it is hoped, will contribute as references in similar analyses and at the same time help to understand the deformation and strain behaviors of structures. (Mori, K.)

  5. Effort problem of chemical pipelines

    Energy Technology Data Exchange (ETDEWEB)

    Okrajni, J.; Ciesla, M.; Mutwil, K. [Silesian Technical University, Katowice (Poland)

    1998-12-31

    The problem of the technical state assessment of the chemical pipelines working under mechanical and thermal loading has been shown in the paper. The pipelines effort after the long time operating period has been analysed. Material geometrical and loading conditions of the crack initiation and crack growth process in the chosen object has been discussed. Areas of the maximal effort have been determined. The material structure charges after the long time operating period have been described. Mechanisms of the crack initiation and crack growth in the pipeline elements have been analysed and mutual relations between the chemical and mechanical influences have been shown. (orig.) 16 refs.

  6. Runaway chemical reaction exposes community to highly toxic chemicals

    International Nuclear Information System (INIS)

    Kaszniak, Mark; Vorderbrueggen, John

    2008-01-01

    The U.S. Chemical Safety and Hazard Investigation Board (CSB) conducted a comprehensive investigation of a runaway chemical reaction at MFG Chemical (MFG) in Dalton, Georgia on April 12, 2004 that resulted in the uncontrolled release of a large quantity of highly toxic and flammable allyl alcohol and allyl chloride into the community. Five people were hospitalized and 154 people required decontamination and treatment for exposure to the chemicals. This included police officers attempting to evacuate the community and ambulance personnel who responded to 911 calls from residents exposed to the chemicals. This paper presents the findings of the CSB report (U.S. Chemical Safety and Hazard Investigation Board (CSB), Investigation Report: Toxic Chemical Vapor Cloud Release, Report No. 2004-09-I-GA, Washington DC, April 2006) including a discussion on tolling practices; scale-up of batch reaction processes; Process Safety Management (PSM) and Risk Management Plan (RMP) implementation; emergency planning by the company, county and the city; and emergency response and mitigation actions taken during the incident. The reactive chemical testing and atmospheric dispersion modeling conducted by CSB after the incident and recommendations adopted by the Board are also discussed

  7. Conducting carbonized polyaniline nanotubes

    International Nuclear Information System (INIS)

    Mentus, Slavko; Ciric-Marjanovic, Gordana; Trchova, Miroslava; Stejskal, Jaroslav

    2009-01-01

    Conducting nitrogen-containing carbon nanotubes were synthesized by the carbonization of self-assembled polyaniline nanotubes protonated with sulfuric acid. Carbonization was carried out in a nitrogen atmosphere at a heating rate of 10 deg. C min -1 up to a maximum temperature of 800 deg. C. The carbonized polyaniline nanotubes which have a typical outer diameter of 100-260 nm, with an inner diameter of 20-170 nm and a length extending from 0.5 to 0.8 μm, accompanied with very thin nanotubes with outer diameters of 8-14 nm, inner diameters 3.0-4.5 nm and length extending from 0.3 to 1.0 μm, were observed by scanning and transmission electron microscopies. Elemental analysis showed 9 wt% of nitrogen in the carbonized product. Conductivity of the nanotubular PANI precursor, amounting to 0.04 S cm -1 , increased to 0.7 S cm -1 upon carbonization. Molecular structure of carbonized polyaniline nanotubes has been analyzed by FTIR and Raman spectroscopies, and their paramagnetic characteristics were compared with the starting PANI nanotubes by EPR spectroscopy.

  8. Conducting carbonized polyaniline nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Mentus, Slavko; Ciric-Marjanovic, Gordana [Faculty of Physical Chemistry, University of Belgrade, Studentski trg 12-16, 11158 Belgrade (Serbia); Trchova, Miroslava; Stejskal, Jaroslav [Institute of Macromolecular Chemistry, Academy of Sciences of the Czech Republic, Heyrovsky Square 2, 162 06 Prague 6 (Czech Republic)], E-mail: gordana@ffh.bg.ac.rs

    2009-06-17

    Conducting nitrogen-containing carbon nanotubes were synthesized by the carbonization of self-assembled polyaniline nanotubes protonated with sulfuric acid. Carbonization was carried out in a nitrogen atmosphere at a heating rate of 10 deg. C min{sup -1} up to a maximum temperature of 800 deg. C. The carbonized polyaniline nanotubes which have a typical outer diameter of 100-260 nm, with an inner diameter of 20-170 nm and a length extending from 0.5 to 0.8 {mu}m, accompanied with very thin nanotubes with outer diameters of 8-14 nm, inner diameters 3.0-4.5 nm and length extending from 0.3 to 1.0 {mu}m, were observed by scanning and transmission electron microscopies. Elemental analysis showed 9 wt% of nitrogen in the carbonized product. Conductivity of the nanotubular PANI precursor, amounting to 0.04 S cm{sup -1}, increased to 0.7 S cm{sup -1} upon carbonization. Molecular structure of carbonized polyaniline nanotubes has been analyzed by FTIR and Raman spectroscopies, and their paramagnetic characteristics were compared with the starting PANI nanotubes by EPR spectroscopy.

  9. Radiative thermal conduction fronts

    International Nuclear Information System (INIS)

    Borkowski, K.J.; Balbus, S.A.; Fristrom, C.C.

    1990-01-01

    The discovery of the O VI interstellar absorption lines in our Galaxy by the Copernicus observatory was a turning point in our understanding of the Interstellar Medium (ISM). It implied the presence of widespread hot (approx. 10 to the 6th power K) gas in disk galaxies. The detection of highly ionized species in quasi-stellar objects' absorption spectra may be the first indirect observation of this hot phase in external disk galaxies. Previous efforts to understand extensive O VI absorption line data from our Galaxy were not very successful in locating the regions where this absorption originates. The location at interfaces between evaporating ISM clouds and hot gas was favored, but recent studies of steady-state conduction fronts in spherical clouds by Ballet, Arnaud, and Rothenflug (1986) and Bohringer and Hartquist (1987) rejected evaporative fronts as the absorption sites. Researchers report here on time-dependent nonequilibrium calculations of planar conductive fronts whose properties match well with observations, and suggest reasons for the difference between the researchers' results and the above. They included magnetic fields in additional models, not reported here, and the conclusions are not affected by their presence

  10. Chemical radioprotection

    International Nuclear Information System (INIS)

    Siegel, G.

    1979-01-01

    A reivew of the problems and progress in the field of chemical radioprotection is given. After defining the field of research, the practical significance of radioprotective substances and the requirements for a utilizable radioprotective preparation are presented. Trends of development of this field of research, the state of the art, and resulting conclusions for the future development of radioprotective substances of practical value are discussed. (author)

  11. Conduction at domain walls in oxide multiferroics

    Science.gov (United States)

    Seidel, J.; Martin, L. W.; He, Q.; Zhan, Q.; Chu, Y.-H.; Rother, A.; Hawkridge, M. E.; Maksymovych, P.; Yu, P.; Gajek, M.; Balke, N.; Kalinin, S. V.; Gemming, S.; Wang, F.; Catalan, G.; Scott, J. F.; Spaldin, N. A.; Orenstein, J.; Ramesh, R.

    2009-03-01

    Domain walls may play an important role in future electronic devices, given their small size as well as the fact that their location can be controlled. Here, we report the observation of room-temperature electronic conductivity at ferroelectric domain walls in the insulating multiferroic BiFeO3. The origin and nature of the observed conductivity are probed using a combination of conductive atomic force microscopy, high-resolution transmission electron microscopy and first-principles density functional computations. Our analyses indicate that the conductivity correlates with structurally driven changes in both the electrostatic potential and the local electronic structure, which shows a decrease in the bandgap at the domain wall. Additionally, we demonstrate the potential for device applications of such conducting nanoscale features.

  12. Conducting polyamine nanocomposites development

    International Nuclear Information System (INIS)

    Nascimento, R.C.; Maciel, T.C.G.L.; Guimaraes, M.J.O.C.; Garcia, M.E.F.

    2010-01-01

    Polymeric nanocomposites are hybrid materials formed by the combination of inorganic nanoparticles dispersed in a polymeric matrix with, at least, one dimension in the nanometer range. It was used as nanoparticles layered and tubular clay minerals, and its insertion and dispersion were conducted through the in situ polymerization technique. As the polymer matrix, it was utilized a polyamine, which, later, will be inserted in a polyacrylamide gel for the development of a compound that aggregates both main characteristics. The nanocomposites were prepared in different polymerization conditions (temperature, concentration and nanoparticle type) and characterized by XRD and FTIR. It was observed that regarding the polymerization conditions, the temperature had influence on the kind of material obtained and on the reaction speed; the type of nanoparticle affected its interaction with the polymer matrix, predominantly providing the formation of nanocomposites by the intercalation mechanism in the layered clay. (author)

  13. Ion-conducting membranes

    Science.gov (United States)

    Masel, Richard I.; Sajjad, Syed Dawar; Gao, Yan; Liu, Zengcai; Chen, Qingmei

    2017-12-26

    An anion-conducting polymeric membrane comprises a terpolymer of styrene, vinylbenzyl-R.sub.s and vinylbenzyl-R.sub.x. R.sub.s is a positively charged cyclic amine group. R.sub.x is at least one constituent selected from the group consisting Cl, OH and a reaction product between an OH or Cl and a species other than a simple amine or a cyclic amine. The total weight of the vinylbenzyl-R.sub.x groups is greater than 0.3% of the total weight of the membrane. In a preferred embodiment, the membrane is a Helper Membrane that increases the faradaic efficiency of an electrochemical cell into which the membrane is incorporated, and also allows product formation at lower voltages than in cells without the Helper Membrane.

  14. Universal mesoscopic conductance fluctuations

    International Nuclear Information System (INIS)

    Evangelou, S.N.

    1992-01-01

    The theory of conductance fluctuations in disordered metallic systems with size large compared to the mean free path of the electron but small compared to localization length is considered. It is demonstrates that fluctuations have an universal character and are due to repulsion between levels and spectral rigidity. The basic fluctuation measures for the energy spectrum in the mesoscopic regime of disordered systems are consistent with the Gaussian random matrix ensemble predictions. Although our disordered electron random matrix ensemble does not belong to the Gaussian ensemble the two ensembles turn out to be essentially similar. The level repulsion and the spectral rigidity found in nuclear spectra should also be observed in the metallic regime of Anderson localization. 7 refs. (orig.)

  15. Analyses of fine paste ceramics

    International Nuclear Information System (INIS)

    Sabloff, J.A.

    1980-01-01

    Four chapters are included: history of Brookhaven fine paste ceramics project, chemical and mathematical procedures employed in Mayan fine paste ceramics project, and compositional and archaeological perspectives on the Mayan fine paste ceramics

  16. Analyses of fine paste ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Sabloff, J A [ed.

    1980-01-01

    Four chapters are included: history of Brookhaven fine paste ceramics project, chemical and mathematical procedures employed in Mayan fine paste ceramics project, and compositional and archaeological perspectives on the Mayan fine paste ceramics. (DLC)

  17. Integration of conducting polymer network in non-conductive polymer substrates

    DEFF Research Database (Denmark)

    Hansen, Thomas Steen; West, Keld; Hassager, Ole

    2006-01-01

    Anew method for integration ofconjugated, inherently conducting polymers into non-conductive polymer substrates has been developed. Alayer of the conducting polymer is polymerised by chemical oxidation, e.g. using Fe(ID) p-toluene sulfonate (ferri tosylate) followed by washing with a solvent which...... simultaneously removes residual and spent oxidant and at the same time dissolves the top layer of the polymer substrate. This results in an integration of the conducting polymer into the surface layers of the polymer substrate. Several combinations of conducting polymers and substrates have been tested...... absorption during sequential reactive ion etching has allowed for analysis of the PEDOT distribution within the surface layer of thePMMA substrate. The surface resistance ofthe conducting polymer layer remains low while the surface layer at the same time adapts some of the mechanical properties...

  18. A conductive surface coating for Si-CNT radiation detectors

    Energy Technology Data Exchange (ETDEWEB)

    Valentini, Antonio, E-mail: antonio.valentini@ba.infn.it [Dipartimento di Fisica, Università degli Studi di Bari, Via Orabona 4, 70125 Bari (Italy); Valentini, Marco [INFN, Sezione di Bari, Via Orabona 4, 70126 Bari (Italy); Ditaranto, Nicoletta [Dipartimento di Chimica, Università degli Studi di Bari, Via Amendola 173, 70126 Bari (Italy); Melisi, Domenico [INFN, Sezione di Bari, Via Orabona 4, 70126 Bari (Italy); Aramo, Carla, E-mail: aramo@na.infn.it [INFN, Sezione di Napoli, Via Cintia 2, 80126 Napoli (Italy); Ambrosio, Antonio [CNR-SPIN U.O.S. di Napoli and Dipartimento di Scienze Fisiche, Università degli Studi di Napoli “Federico II”, Via Cintia 2, 80126 Napoli (Italy); Casamassima, Giuseppe [Dipartimento di Fisica, Università degli Studi di Bari, Via Orabona 4, 70125 Bari (Italy); INFN, Sezione di Bari, Via Orabona 4, 70126 Bari (Italy); Cilmo, Marco [INFN, Sezione di Napoli, and Dipartimento di Scienze Fisiche, Università degli Studi di Napoli “Federico II”, Via Cintia 2, 80126 Napoli (Italy); Fiandrini, Emanuele [INFN, Sezione di Perugia, and Dipartimento di Fisica, Università degli Studi di Perugia, Piazza Università 1, 06100 Perugia (Italy); Grossi, Valentina [INFN, Sezione di L’Aquila, and Dipartimento di Scienze Fisiche e Chimiche, Università degli Studi dell’Aquila, Via Vetoio 10 Coppito, 67100 L’Aquila (Italy); and others

    2015-08-01

    Silicon–Carbon Nanotube radiation detectors need an electrically conductive coating layer to avoid the nanotube detachment from the silicon substrate and uniformly transmit the electric field to the entire nanotube active surface. Coating material must be transparent to the radiation of interest, and must provide the drain voltage necessary to collect charges generated by incident photons. For this purpose various materials have been tested and proposed in photodetector and photoconverter applications. In this article interface properties and electrical contact behavior of Indium Tin Oxide films on Carbon Nanotubes have been analyzed. Ion Beam Sputtering has been used to grow the transparent conductive layer on the nanotubes. The films were deposited at room temperature with Oxygen/Argon mixture into the sputtering beam, at fixed current and for different beam energies. Optical and electrical analyses have been performed on films. Surface chemical analysis and in depth profiling results obtained by X-ray Photoelectron Spectroscopy of the Indium Tin Oxide layer on nanotubes have been used to obtain the interface composition. Results have been applied in photodetectors realization based on multi wall Carbon Nanotubes on silicon. - Highlights: • ITO was deposited by Ion Beam Sputtering on MWCNT. • ITO on CNT makes an inter-diffusion layer of the order of one hundred nanometers. • Improvements of quantum efficiency of photon detectors based on CNT with ITO.

  19. Synthesis of dye linked conducting block copolymers, dye linked conducting homopolymers and preliminary application to photovoltaics

    DEFF Research Database (Denmark)

    Krebs, Frederik C; Hagemann, O.; Jørgensen, M.

    2004-01-01

    A synthetic approach to the synthesis of a large super molecule composed of two chemically different conducting polymer blocks with, respectively, high and low lying electronic energy levels linked through a porphyrin dye molecule is presented. The synthetic strategies to these molecular architec...

  20. Household Chemical Emergencies

    Science.gov (United States)

    ... Content Home Be Informed Household Chemical Emergencies Household Chemical Emergencies Although the risk of a chemical accident ... reduce the risk of injury. Before a Household Chemical Emergency It is critical to store household chemicals ...

  1. Thermal conductivity of different colored compomers.

    Science.gov (United States)

    Guler, Cigdem; Keles, Ali; Guler, Mehmet S; Karagoz, Sendogan; Cora, Ömer N; Keskin, Gul

    2017-11-10

    Compomers are mostly used in primary dentition. The thermal conductivity properties of traditional or colored compomers have not been investigated in detail so far. The aim of this in vitro study was to assess and compare the thermal conductivities of traditional and colored compomers. Two sets of compomers - namely, Twinky Star (available in berry, lemon, green, silver, blue, pink, gold and orange shades) and Dyract Extra (available in B1, A3 and A2 shades) - were included in this study. All of the traditional and colored compomers were applied to standard molds and polymerized according to the manufacturers' instructions. Three samples were prepared from each compomer. Measurements were conducted using a heat conduction test setup, and the coefficient of heat conductivity was calculated for each material. The heat conductivity coefficients were statistically analyzed using Kruskal-Wallis and Duncan tests. Uncertainty analysis was also performed on the calculated coefficients of heat conductivity. Statistically significant differences were found (p<0.05) between the thermal conductivity properties of the traditional and colored compomers examined. Among all of the tested compomers, the silver shade compomer exhibited the highest coefficient of heat conductivity (p<0.05), while the berry shade exhibited the lowest coefficient (p<0.05). Uncertainty analyses revealed that 6 out of 11 samples showed significant differences. The silver shade compomer should be avoided in deep cavities. The material properties could be improved for colored compomers.

  2. Equações de regressão para estimar valores energéticos do grão de trigo e seus subprodutos para frangos de corte, a partir de análises químicas Regression equations to evaluate the energy values of wheat grain and its by-products for broiler chickens from chemical analyses

    Directory of Open Access Journals (Sweden)

    F.M.O. Borges

    2003-12-01

    que significou pouca influência da metodologia sobre essa medida. A FDN não mostrou ser melhor preditor de EM do que a FB.One experiment was run with broiler chickens, to obtain prediction equations for metabolizable energy (ME based on feedstuffs chemical analyses, and determined ME of wheat grain and its by-products, using four different methodologies. Seven wheat grain by-products were used in five treatments: wheat grain, wheat germ, white wheat flour, dark wheat flour, wheat bran for human use, wheat bran for animal use and rough wheat bran. Based on chemical analyses of crude fiber (CF, ether extract (EE, crude protein (CP, ash (AS and starch (ST of the feeds and the determined values of apparent energy (MEA, true energy (MEV, apparent corrected energy (MEAn and true energy corrected by nitrogen balance (MEVn in five treatments, prediction equations were obtained using the stepwise procedure. CF showed the best relationship with metabolizable energy values, however, this variable alone was not enough for a good estimate of the energy values (R² below 0.80. When EE and CP were included in the equations, R² increased to 0.90 or higher in most estimates. When the equations were calculated with all treatments, the equation for MEA were less precise and R² decreased. When ME data of the traditional or force-feeding methods were used separately, the precision of the equations increases (R² higher than 0.85. For MEV and MEVn values, the best multiple linear equations included CF, EE and CP (R²>0.90, independently of using all experimental data or separating by methodology. The estimates of MEVn values showed high precision and the linear coefficients (a of the equations were similar for all treatments or methodologies. Therefore, it explains the small influence of the different methodologies on this parameter. NDF was not a better predictor of ME than CF.

  3. Finite element analyses for RF photoinjector gun cavities

    International Nuclear Information System (INIS)

    Marhauser, F.

    2006-01-01

    This paper details electromagnetical, thermal and structural 3D Finite Element Analyses (FEA) for normal conducting RF photoinjector gun cavities. The simulation methods are described extensively. Achieved results are presented. (orig.)

  4. Finite element analyses for RF photoinjector gun cavities

    Energy Technology Data Exchange (ETDEWEB)

    Marhauser, F. [Berliner Elektronenspeicherring-Gesellschaft fuer Synchrotronstrahlung mbH (BESSY), Berlin (Germany)

    2006-07-01

    This paper details electromagnetical, thermal and structural 3D Finite Element Analyses (FEA) for normal conducting RF photoinjector gun cavities. The simulation methods are described extensively. Achieved results are presented. (orig.)

  5. Control charts technique - a tool to data analysis for chemical experiments

    International Nuclear Information System (INIS)

    Yadav, M.B.; Venugopal, V.

    1999-01-01

    A procedure using control charts technique has been developed to analyse data of a chemical experiment which was conducted to assign a value to uranium content in Rb 2 U(SO 4 ) 3 . A value of (34.164 ± 0.031)% has been assigned against (34.167 ± 0.042)% already assigned by analysis of variance (ANOVA) technique. These values do not differ significantly. Merits and demerits of the two techniques have been discussed. (author)

  6. Chemical cosmology

    CERN Document Server

    Boeyens, Jan CA

    2010-01-01

    The composition of the most remote objects brought into view by the Hubble telescope can no longer be reconciled with the nucleogenesis of standard cosmology and the alternative explanation, in terms of the LAMBDA-Cold-Dark-Matter model, has no recognizable chemical basis. A more rational scheme, based on the chemistry and periodicity of atomic matter, opens up an exciting new interpretation of the cosmos in terms of projective geometry and general relativity. The response of atomic structure to environmental pressure predicts non-Doppler cosmical redshifts and equilibrium nucleogenesis by alp

  7. Cooling tower wood sampling and analyses: A case study

    International Nuclear Information System (INIS)

    Haymore, J.L.

    1985-01-01

    Extensive wood sampling and analyses programs were initiated on crossflow and counterflow cooling towers that have been in service since 1951 and 1955, respectively. Wood samples were taken from all areas of the towers and were subjected to biological, chemical and physical tests. The tests and results for the analyses are discussed. The results indicate the degree of wood deterioration, and areas of the towers which experience the most advanced degree of degradation

  8. Fully coupled heat conduction and deformation analyses of visco-elastic solids

    KAUST Repository

    Khan, Kamran; Muliana, Anastasia Hanifah

    2012-01-01

    the temperature in a viscoelastic body. The rate of stress relaxation (or the rate of creep) and the mechanical and physical properties of visco-elastic materials, such as polymers, vary with temperature. This study aims at understanding the effect of coupling

  9. Analyses of Effects of Cutting Parameters on Cutting Edge Temperature Using Inverse Heat Conduction Technique

    Directory of Open Access Journals (Sweden)

    Marcelo Ribeiro dos Santos

    2014-01-01

    Full Text Available During machining energy is transformed into heat due to plastic deformation of the workpiece surface and friction between tool and workpiece. High temperatures are generated in the region of the cutting edge, which have a very important influence on wear rate of the cutting tool and on tool life. This work proposes the estimation of heat flux at the chip-tool interface using inverse techniques. Factors which influence the temperature distribution at the AISI M32C high speed steel tool rake face during machining of a ABNT 12L14 steel workpiece were also investigated. The temperature distribution was predicted using finite volume elements. A transient 3D numerical code using irregular and nonstaggered mesh was developed to solve the nonlinear heat diffusion equation. To validate the software, experimental tests were made. The inverse problem was solved using the function specification method. Heat fluxes at the tool-workpiece interface were estimated using inverse problems techniques and experimental temperatures. Tests were performed to study the effect of cutting parameters on cutting edge temperature. The results were compared with those of the tool-work thermocouple technique and a fair agreement was obtained.

  10. Identifying Key Workplace Stressors Affecting Twentieth Air Force: Analyses Conducted from December 2012 Through February 2013

    Science.gov (United States)

    2014-01-01

    24-hour basis include nursing , air traffic control, manufacturing, police service, and fire protection. Many studies have shown that evening, night...of occupational injuries for a variety of jobs, including construction workers, nurses , miners, truck drivers, firefighters, and nuclear power plant...lish a strict schedule of AFS-specific focus group times in advance. We could not reschedule if the times proved inconvenient for participants

  11. Chemical source characterization of residential wood combustion emissions in Denver, Colorado; Bakersfield, California; and Mammoth Lakes, California

    International Nuclear Information System (INIS)

    Houck, J.E.; Goulet, J.M.; Chow, J.C.; Watson, J.G.

    1989-01-01

    The chemical composition of residential wood combustion particulate emissions was determined for fireplaces and woodstoves. Burn rates, burn patterns, wood burning appliances, and cordwood types characteristic of Denver, Colorado; Bakersfield, California; and Mammoth Lakes, California, were used during sample collection. Samples were collected using a dilution/cooling system to ensure that condensible compounds were captured. Analyses for 44 chemical species were conducted. Source profiles for use in chemical mass balance (CMB) modeling were calculated from the analytical data. The principal chemical species comprising the profiles were organic compounds and elemental carbon. The minor chemical species were sulfur, chlorine, potassium, sodium, calcium, zinc, nitrate, and ammonium. Virtually all potassium was in a water-soluble form, and sulfur emissions between fireplaces and woodstoves were noted. Area-specific source profiles for fireplaces, woodstoves, and overall residential wood combustion are presented

  12. Improving electrical conductivity in polycarbonate nanocomposites using highly conductive PEDOT/PSS coated MWCNTs

    KAUST Repository

    Zhou, Jian

    2013-07-10

    We describe a strategy to design highly electrically conductive polycarbonate nanocomposites by using multiwalled carbon nanotubes (MWCNTs) coated with a thin layer of poly(3,4-ethylenedioxythiophene)/ poly(styrenesulfonate), a conductive polymer. We found that this coating method improves the electrical properties of the nanocomposites in two ways. First, the coating becomes the main electrical conductive path. Second, the coating promotes the formation of a percolation network at a low filler concentration (0.3 wt %). To tailor the electrical properties of the conductive polymer coating, we used a polar solvent ethylene glycol, and we can tune the final properties of the nanocomposite by controlling the concentrations of the elementary constituents or the intrinsic properties of the conductive polymer coating. This very flexible technique allows for tailoring the properties of the final product. © 2013 American Chemical Society.

  13. Structure of conduction electrons on polysilanes

    Energy Technology Data Exchange (ETDEWEB)

    Ichikawa, Tsuneki [Hokkaido Univ., Sapporo (Japan); Kumagai, Jun

    1998-10-01

    The orbital structures of conduction electrons on permethylated oligosilane, Si{sub 2n}(CH{sub 3}){sub 2n+2}(n = 2 - 8), and poly(cyclohexylmethylsilane) have been determined by the electron spin-echo envelope modulation signals of the radical anions of these silanes in a deuterated rigid matrix at 77 K. The conduction electron on permethylated oligosilane is delocalized over the entire main chain, whereas that on poly(cyclohexylmethylsilane) is localized on a part of the main chain composed of about six Si atoms. Quantum-chemical calculations suggest that Anderson localization due to fluctuation of {sigma} conjugation by conformational disorder of the main chain is responsible for the localization of both the conduction electron and the hole. (author)

  14. Electrical and Electrochemical Properties of Conducting Polymers

    Directory of Open Access Journals (Sweden)

    Thanh-Hai Le

    2017-04-01

    Full Text Available Conducting polymers (CPs have received much attention in both fundamental and practical studies because they have electrical and electrochemical properties similar to those of both traditional semiconductors and metals. CPs possess excellent characteristics such as mild synthesis and processing conditions, chemical and structural diversity, tunable conductivity, and structural flexibility. Advances in nanotechnology have allowed the fabrication of versatile CP nanomaterials with improved performance for various applications including electronics, optoelectronics, sensors, and energy devices. The aim of this review is to explore the conductivity mechanisms and electrical and electrochemical properties of CPs and to discuss the factors that significantly affect these properties. The size and morphology of the materials are also discussed as key parameters that affect their major properties. Finally, the latest trends in research on electrochemical capacitors and sensors are introduced through an in-depth discussion of the most remarkable studies reported since 2003.

  15. Similarity analyses of chromatographic herbal fingerprints: A review

    International Nuclear Information System (INIS)

    Goodarzi, Mohammad; Russell, Paul J.; Vander Heyden, Yvan

    2013-01-01

    Graphical abstract: -- Highlights: •Similarity analyses of herbal fingerprints are reviewed. •Different (dis)similarity approaches are discussed. •(Dis)similarity-metrics and exploratory-analysis approaches are illustrated. •Correlation and distance-based measures are overviewed. •Similarity analyses illustrated by several case studies. -- Abstract: Herbal medicines are becoming again more popular in the developed countries because being “natural” and people thus often assume that they are inherently safe. Herbs have also been used worldwide for many centuries in the traditional medicines. The concern of their safety and efficacy has grown since increasing western interest. Herbal materials and their extracts are very complex, often including hundreds of compounds. A thorough understanding of their chemical composition is essential for conducting a safety risk assessment. However, herbal material can show considerable variability. The chemical constituents and their amounts in a herb can be different, due to growing conditions, such as climate and soil, the drying process, the harvest season, etc. Among the analytical methods, chromatographic fingerprinting has been recommended as a potential and reliable methodology for the identification and quality control of herbal medicines. Identification is needed to avoid fraud and adulteration. Currently, analyzing chromatographic herbal fingerprint data sets has become one of the most applied tools in quality assessment of herbal materials. Mostly, the entire chromatographic profiles are used to identify or to evaluate the quality of the herbs investigated. Occasionally only a limited number of compounds are considered. One approach to the safety risk assessment is to determine whether the herbal material is substantially equivalent to that which is either readily consumed in the diet, has a history of application or has earlier been commercialized i.e. to what is considered as reference material. In order

  16. Similarity analyses of chromatographic herbal fingerprints: A review

    Energy Technology Data Exchange (ETDEWEB)

    Goodarzi, Mohammad [Department of Analytical Chemistry and Pharmaceutical Technology, Center for Pharmaceutical Research, Vrije Universiteit Brussel, Laarbeeklaan 103, B-1090 Brussels (Belgium); Russell, Paul J. [Safety and Environmental Assurance Centre, Unilever, Colworth Science Park, Sharnbrook, Bedfordshire MK44 1LQ (United Kingdom); Vander Heyden, Yvan, E-mail: yvanvdh@vub.ac.be [Department of Analytical Chemistry and Pharmaceutical Technology, Center for Pharmaceutical Research, Vrije Universiteit Brussel, Laarbeeklaan 103, B-1090 Brussels (Belgium)

    2013-12-04

    Graphical abstract: -- Highlights: •Similarity analyses of herbal fingerprints are reviewed. •Different (dis)similarity approaches are discussed. •(Dis)similarity-metrics and exploratory-analysis approaches are illustrated. •Correlation and distance-based measures are overviewed. •Similarity analyses illustrated by several case studies. -- Abstract: Herbal medicines are becoming again more popular in the developed countries because being “natural” and people thus often assume that they are inherently safe. Herbs have also been used worldwide for many centuries in the traditional medicines. The concern of their safety and efficacy has grown since increasing western interest. Herbal materials and their extracts are very complex, often including hundreds of compounds. A thorough understanding of their chemical composition is essential for conducting a safety risk assessment. However, herbal material can show considerable variability. The chemical constituents and their amounts in a herb can be different, due to growing conditions, such as climate and soil, the drying process, the harvest season, etc. Among the analytical methods, chromatographic fingerprinting has been recommended as a potential and reliable methodology for the identification and quality control of herbal medicines. Identification is needed to avoid fraud and adulteration. Currently, analyzing chromatographic herbal fingerprint data sets has become one of the most applied tools in quality assessment of herbal materials. Mostly, the entire chromatographic profiles are used to identify or to evaluate the quality of the herbs investigated. Occasionally only a limited number of compounds are considered. One approach to the safety risk assessment is to determine whether the herbal material is substantially equivalent to that which is either readily consumed in the diet, has a history of application or has earlier been commercialized i.e. to what is considered as reference material. In order

  17. Association between Adult Height and Risk of Colorectal, Lung, and Prostate Cancer : Results from Meta-analyses of Prospective Studies and Mendelian Randomization Analyses

    NARCIS (Netherlands)

    Khankari, Nikhil K.; Shu, Xiao Ou; Wen, Wanqing; Kraft, Peter; Lindström, Sara; Peters, Ulrike; Schildkraut, Joellen; Schumacher, Fredrick; Bofetta, Paolo; Risch, Angela; Bickeböller, Heike; Amos, Christopher I.; Easton, Douglas; Eeles, Rosalind A.; Gruber, Stephen B.; Haiman, Christopher A.; Hunter, David J.; Chanock, Stephen J.; Pierce, Brandon L.; Zheng, Wei; Blalock, Kendra; Campbell, Peter T.; Casey, Graham; Conti, David V.; Edlund, Christopher K.; Figueiredo, Jane; James Gauderman, W.; Gong, Jian; Green, Roger C.; Harju, John F.; Harrison, Tabitha A.; Jacobs, Eric J.; Jenkins, Mark A.; Jiao, Shuo; Li, Li; Lin, Yi; Manion, Frank J.; Moreno, Victor; Mukherjee, Bhramar; Raskin, Leon; Schumacher, Fredrick R.; Seminara, Daniela; Severi, Gianluca; Stenzel, Stephanie L.; Thomas, Duncan C.; Hopper, John L.; Southey, Melissa C.; Makalic, Enes; Schmidt, Daniel F.; Fletcher, Olivia; Peto, Julian; Gibson, Lorna; dos Santos Silva, Isabel; Ahsan, Habib; Whittemore, Alice; Waisfisz, Quinten; Meijers-Heijboer, Hanne; Adank, Muriel; van der Luijt, Rob B.; Uitterlinden, Andre G.; Hofman, Albert; Meindl, Alfons; Schmutzler, Rita K.; Müller-Myhsok, Bertram; Lichtner, Peter; Nevanlinna, Heli; Muranen, Taru A.; Aittomäki, Kristiina; Blomqvist, Carl; Chang-Claude, Jenny; Hein, Rebecca; Dahmen, Norbert; Beckman, Lars; Crisponi, Laura; Hall, Per; Czene, Kamila; Irwanto, Astrid; Liu, Jianjun; Easton, Douglas F.; Turnbull, Clare; Rahman, Nazneen; Eeles, Rosalind; Kote-Jarai, Zsofia; Muir, Kenneth; Giles, Graham; Neal, David; Donovan, Jenny L.; Hamdy, Freddie C.; Wiklund, Fredrik; Gronberg, Henrik; Haiman, Christopher; Schumacher, Fred; Travis, Ruth; Riboli, Elio; Hunter, David; Gapstur, Susan; Berndt, Sonja; Chanock, Stephen; Han, Younghun; Su, Li; Wei, Yongyue; Hung, Rayjean J.; Brhane, Yonathan; McLaughlin, John; Brennan, Paul; McKay, James D.; Rosenberger, Albert; Houlston, Richard S.; Caporaso, Neil; Teresa Landi, Maria; Heinrich, Joachim; Wu, Xifeng; Ye, Yuanqing; Christiani, David C.

    2016-01-01

    Background: Observational studies examining associations between adult height and risk of colorectal, prostate, and lung cancers have generated mixed results. We conducted meta-analyses using data from prospective cohort studies and further carried out Mendelian randomization analyses, using

  18. SYNTHESIS, HIRSHFELD SURFACE ANALYSES AND ...

    African Journals Online (AJOL)

    2016 Chemical Society of Ethiopia ... We report here the synthesis of a dinuclear Mn(II) complex with mixed co-ligands. The ... The total lattice energy is partitioned .... The χMT value for the complex 1 was 8.51 cm3 K mol−1 at 300 K, and this is ...

  19. Advanced Proton Conducting Polymer Electrolytes for Electrochemical Capacitors

    Science.gov (United States)

    Gao, Han

    Research on solid electrochemical energy storage devices aims to provide high performance, low cost, and safe operation solutions for emerging applications from flexible consumer electronics to microelectronics. Polymer electrolytes, minimizing device sealing and liquid electrolyte leakage, are key enablers for these next-generation technologies. In this thesis, a novel proton-conducing polymer electrolyte system has been developed using heteropolyacids (HPAs) and polyvinyl alcohol for electrochemical capacitors. A thorough understanding of proton conduction mechanisms of HPAs together with the interactions among HPAs, additives, and polymer framework has been developed. Structure and chemical bonding of the electrolytes have been studied extensively to identify and elucidate key attributes affecting the electrolyte properties. Numerical models describing the proton conduction mechanism have been applied to differentiate those attributes. The performance optimization of the polymer electrolytes through additives, polymer structural modifications, and synthesis of alternative HPAs has achieved several important milestones, including: (a) high proton mobility and proton density; (b) good ion accessibility at electrode/electrolyte interface; (c) wide electrochemical stability window; and (d) good environmental stability. Specifically, high proton mobility has been addressed by cross-linking the polymer framework to improve the water storage capability at normal-to-high humidity conditions (e.g. 50-80% RH) as well as by incorporating nano-fillers to enhance the water retention at normal humidity levels (e.g. 30-60% RH). High proton density has been reached by utilizing additional proton donors (i.e. acidic plasticizers) and by developing different HPAs. Good ion accessibility has been achieved through addition of plasticizers. Electrochemical stability window of the electrolyte system has also been investigated and expanded by utilizing HPAs with different heteroatoms

  20. Stretchable, Porous, and Conductive Energy Textiles

    KAUST Repository

    Hu, Liangbing; Pasta, Mauro; Mantia, Fabio La; Cui, LiFeng; Jeong, Sangmoo; Deshazer, Heather Dawn; Choi, Jang Wook; Han, Seung Min; Cui, Yi

    2010-01-01

    Recently there is strong interest in lightweight, flexible, and wearable electronics to meet the technological demands of modern society. Integrated energy storage devices of this type are a key area that is still significantly underdeveloped. Here, we describe wearable power devices using everyday textiles as the platform. With an extremely simple "dipping and drying" process using single-walled carbon nanotube (SWNT) ink, we produced highly conductive textiles with conductivity of 125 S cm-1 and sheet resistance less than 1 Ω/sq. Such conductive textiles show outstanding flexibility and stretchability and demonstrate strong adhesion between the SWNTs and the textiles of interest. Supercapacitors made from these conductive textiles show high areal capacitance, up to 0.48F/cm2, and high specific energy. We demonstrate the loading of pseudocapacitor materials into these conductive textiles that leads to a 24-fold increase of the areal capacitance of the device. These highly conductive textiles can provide new design opportunities for wearable electronics and energy storage applications. © 2010 American Chemical Society.

  1. Stretchable, Porous, and Conductive Energy Textiles

    KAUST Repository

    Hu, Liangbing

    2010-02-10

    Recently there is strong interest in lightweight, flexible, and wearable electronics to meet the technological demands of modern society. Integrated energy storage devices of this type are a key area that is still significantly underdeveloped. Here, we describe wearable power devices using everyday textiles as the platform. With an extremely simple "dipping and drying" process using single-walled carbon nanotube (SWNT) ink, we produced highly conductive textiles with conductivity of 125 S cm-1 and sheet resistance less than 1 Ω/sq. Such conductive textiles show outstanding flexibility and stretchability and demonstrate strong adhesion between the SWNTs and the textiles of interest. Supercapacitors made from these conductive textiles show high areal capacitance, up to 0.48F/cm2, and high specific energy. We demonstrate the loading of pseudocapacitor materials into these conductive textiles that leads to a 24-fold increase of the areal capacitance of the device. These highly conductive textiles can provide new design opportunities for wearable electronics and energy storage applications. © 2010 American Chemical Society.

  2. US Human Rights Conduct and International Legitimacy

    DEFF Research Database (Denmark)

    Keating, Vincent Charles

    Did the Bush administration fundamentally harm the international human rights system through its rejection of human rights norms? This is the central question explored within US Human Rights Conduct and International Legitimacy, which analyses the practices of legitimacy between the Bush...... nations have followed in America's footsteps, and that the Bush administration's deviation from international norms has served to reaffirm worldwide commitment to human rights....

  3. The TSCA interagency testing committee`s approaches to screening and scoring chemicals and chemical groups: 1977-1983

    Energy Technology Data Exchange (ETDEWEB)

    Walker, J.D. [Environmental Protection Agency, Washington, DC (United States)

    1990-12-31

    This paper describes the TSCA interagency testing committee`s (ITC) approaches to screening and scoring chemicals and chemical groups between 1977 and 1983. During this time the ITC conducted five scoring exercises to select chemicals and chemical groups for detailed review and to determine which of these chemicals and chemical groups should be added to the TSCA Section 4(e) Priority Testing List. 29 refs., 1 fig., 2 tabs.

  4. CAMEO Chemicals Software

    Science.gov (United States)

    CAMEO Chemicals is an extensive chemical database, available for download, with critical response information for thousands of chemicals, and a tool that tells you what reactions might occur if chemicals were mixed together.

  5. Sample preparation in foodomic analyses.

    Science.gov (United States)

    Martinović, Tamara; Šrajer Gajdošik, Martina; Josić, Djuro

    2018-04-16

    Representative sampling and adequate sample preparation are key factors for successful performance of further steps in foodomic analyses, as well as for correct data interpretation. Incorrect sampling and improper sample preparation can be sources of severe bias in foodomic analyses. It is well known that both wrong sampling and sample treatment cannot be corrected anymore. These, in the past frequently neglected facts, are now taken into consideration, and the progress in sampling and sample preparation in foodomics is reviewed here. We report the use of highly sophisticated instruments for both high-performance and high-throughput analyses, as well as miniaturization and the use of laboratory robotics in metabolomics, proteomics, peptidomics and genomics. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  6. CHEMICAL EVOLUTION

    Energy Technology Data Exchange (ETDEWEB)

    Calvin, Melvin

    1965-06-01

    How did life come to be on the surface of the earth? Darwin himself recognized that his basic idea of evolution by variation and natural selection must be a continuous process extending backward in time through that period in which the first living things arose and into the period of 'Chemical Evolution' which preceded it. We are approaching the examination of these events by two routes. One is to seek for evidence in the ancient rocks of the earth which were laid down prior to that time in which organisms capable of leaving their skeletons in the rocks to be fossilized were in existence. This period is sometime prior to approximately 600 million years ago. The earth is believed to have taken its present form approximately 4700 million years ago. We have found in rocks whose age is about 1000 million years certain organic molecules which are closely related to the green pigment of plants, chlorophyll. This seems to establish that green plants were already fluorishing prior to that time. We have now found in rocks of still greater age, namely, 2500 million years, the same kinds of molecules mentioned above which can be attributed to the presence of living organisms. If these molecules are as old as the rocks, we have thus shortened the time available for the generation of the complex biosynthetic sequences which give rise to these specific hydrocarbons (polyisoprenoids) to less than 2000 million years.

  7. ICPP [Idaho Chemical Processing Plant] environmental monitoring report, CY-1988

    International Nuclear Information System (INIS)

    Krivanek, K.R.

    1989-08-01

    Summarized in this report are the data collected through Environmental Monitoring programs conducted at the Idaho Chemical Processing Plant (ICPP) by the Environmental Engineering (EE) Section of the Nuclear and Industrial Safety (N and IS) Department. The ICPP is responsible for complying with all applicable Federal, State, Local and DOE Rules, Regulations and Orders. Radiological effluent and emissions are regulated by the DOE. The Environmental Protection Agency (EPA) regulates all nonradiological waste resulting from the ICPP operations including all airborne, liquid, and solid waste. The EE subsection completed a Quality Assurance (QA) Plan for Environmental Monitoring activities during the third quarter of 1986. QA activities have resulted in the ICPP's implementation of the Environmental Protection Agency rules and guidelines pertaining to the collection, analyses, and reporting of environmentally related samples. Where no approved methods for analyses existed for radionuclides, currently used methods were submitted for the EPA approval. 33 figs., 14 tabs

  8. Descriptive Analyses of Mechanical Systems

    DEFF Research Database (Denmark)

    Andreasen, Mogens Myrup; Hansen, Claus Thorp

    2003-01-01

    Forord Produktanalyse og teknologianalyse kan gennmføres med et bredt socio-teknisk sigte med henblik på at forstå kulturelle, sociologiske, designmæssige, forretningsmæssige og mange andre forhold. Et delområde heri er systemisk analyse og beskrivelse af produkter og systemer. Nærværende kompend...

  9. Analysing and Comparing Encodability Criteria

    Directory of Open Access Journals (Sweden)

    Kirstin Peters

    2015-08-01

    Full Text Available Encodings or the proof of their absence are the main way to compare process calculi. To analyse the quality of encodings and to rule out trivial or meaningless encodings, they are augmented with quality criteria. There exists a bunch of different criteria and different variants of criteria in order to reason in different settings. This leads to incomparable results. Moreover it is not always clear whether the criteria used to obtain a result in a particular setting do indeed fit to this setting. We show how to formally reason about and compare encodability criteria by mapping them on requirements on a relation between source and target terms that is induced by the encoding function. In particular we analyse the common criteria full abstraction, operational correspondence, divergence reflection, success sensitiveness, and respect of barbs; e.g. we analyse the exact nature of the simulation relation (coupled simulation versus bisimulation that is induced by different variants of operational correspondence. This way we reduce the problem of analysing or comparing encodability criteria to the better understood problem of comparing relations on processes.

  10. Analysing Children's Drawings: Applied Imagination

    Science.gov (United States)

    Bland, Derek

    2012-01-01

    This article centres on a research project in which freehand drawings provided a richly creative and colourful data source of children's imagined, ideal learning environments. Issues concerning the analysis of the visual data are discussed, in particular, how imaginative content was analysed and how the analytical process was dependent on an…

  11. Impact analyses after pipe rupture

    International Nuclear Information System (INIS)

    Chun, R.C.; Chuang, T.Y.

    1983-01-01

    Two of the French pipe whip experiments are reproduced with the computer code WIPS. The WIPS results are in good agreement with the experimental data and the French computer code TEDEL. This justifies the use of its pipe element in conjunction with its U-bar element in a simplified method of impact analyses

  12. Millifluidic droplet analyser for microbiology

    NARCIS (Netherlands)

    Baraban, L.; Bertholle, F.; Salverda, M.L.M.; Bremond, N.; Panizza, P.; Baudry, J.; Visser, de J.A.G.M.; Bibette, J.

    2011-01-01

    We present a novel millifluidic droplet analyser (MDA) for precisely monitoring the dynamics of microbial populations over multiple generations in numerous (=103) aqueous emulsion droplets (100 nL). As a first application, we measure the growth rate of a bacterial strain and determine the minimal

  13. Analyser of sweeping electron beam

    International Nuclear Information System (INIS)

    Strasser, A.

    1993-01-01

    The electron beam analyser has an array of conductors that can be positioned in the field of the sweeping beam, an electronic signal treatment system for the analysis of the signals generated in the conductors by the incident electrons and a display for the different characteristics of the electron beam

  14. Ionic conductivity and diffusion coefficient of barium-chloride-based ...

    Indian Academy of Sciences (India)

    styrenesulphonic acid) with bariumchloride dihydrate (BaCl 2 ·2H 2 O) salt complex has been synthesized following the usual solution casting. The ionic conductivity of polymer electrolyte was analysed by impedance spectroscopy. The highest room ...

  15. Code of conduct for scientists (abstract)

    International Nuclear Information System (INIS)

    Khurshid, S.J.

    2011-01-01

    The emergence of advanced technologies in the last three decades and extraordinary progress in our knowledge on the basic Physical, Chemical and Biological properties of living matter has offered tremendous benefits to human beings but simultaneously highlighted the need of higher awareness and responsibility by the scientists of 21 century. Scientist is not born with ethics, nor science is ethically neutral, but there are ethical dimensions to scientific work. There is need to evolve an appropriate Code of Conduct for scientist particularly working in every field of Science. However, while considering the contents, promulgation and adaptation of Codes of Conduct for Scientists, a balance is needed to be maintained between freedom of scientists and at the same time some binding on them in the form of Code of Conducts. The use of good and safe laboratory procedures, whether, codified by law or by common practice must also be considered as part of the moral duties of scientists. It is internationally agreed that a general Code of Conduct can't be formulated for all the scientists universally, but there should be a set of 'building blocks' aimed at establishing the Code of Conduct for Scientists either as individual researcher or responsible for direction, evaluation, monitoring of scientific activities at the institutional or organizational level. (author)

  16. Investigation of the technology of conductive yarns manufacturing

    Science.gov (United States)

    Ryklin, Dzmitry; Medvetski, Sergey

    2017-10-01

    The paper is devoted to development of technology of electrically conductive yarn production. This technology allows manufacturing conductive yarns of copper wire and polyester filament yarns. Method of the predicting of the conductive yarn breaking force was developed on the base of analysing of load-elongation curves of each strand of the yarn. Also the method of the predicting of the conductive yarn diameter was offered. Investigation shows that conductive yarns can be integrated into the textiles structure using sewing or embroidery equipment. Application of developed conductive yarn is wearable electronics creating with wide range of functions, for example, for specific health issue monitoring, navigation tools or communication gadgets.

  17. Physical and Chemical Analysis of the Germinating and Nutritional Properties of Irradiated Wheat; Analyse Physico-Chimique des Caracteristiques Germinatives et Nutritives du Ble Irradie; Fizicheskie i khimicheskie analizy svojstv rosta i pitatel'nykh kachestv obluchennoj pshenitsy; Analisis Fisicoquimico de Trigo Irradiado: Estudio de sus Caracteristicas Germinativas y Nutricionales

    Energy Technology Data Exchange (ETDEWEB)

    Pahissa Campa, J.; Gabarain, R. V.A.; De Pahissa, M. H.H. [Comision Nacional de Energia Atomica (Argentina); Bassa, L. [Junta Nacional de Granos, Buenos Aires (Argentina)

    1966-11-15

    The authors exposed wheat to radiation at various dose levels for the purpose of determining the physical and chemical effects on whole grain (its behaviour as seed) and flour (nutritional value). They used the Surena M.A.G. variety of wheat, which is cultivated in Argentina and was supplied by the National Wheat Board. A Canadian Gamma cell 220 apparatus was employed, equipped with a 13 000-Ci {sup 60}Co source and capable of delivering a dose of approximately 1 Mrad/h. Irradiation was carried out at the following dose levels: 10, 15, 20, 50, 100, 150, 200, 300, 500, 1000, 1500 and 2000 krad. The following analytical values were determined: (a) whole wheat - hectolitric weight, moisture content, percentage of proteins (nitrogen content x 13.5), Zeleny figure, ash content, ability to germinate (two and three days); (b) flour - moisture content, percentage of proteins (nitrogen content x 13.5), Zeleny figure, ash content, alcoholic acidity, maltose content, wet gluten content, dry gluten content, farinograph values (absorption of water, development time, degree of sponginess, Brabender moisture tester), alveograph values (stretch-resistance, stretch, degree and rate of deformation, ratio of stretch-resistance to stretch), extensometer values (work required to stretch dough, stretch-resistance, stretch, ratio of stretch-resistance to stretch), bread-making characteristics (weight of bread, volume of bread and specific volume). The same values were also determined for non-irradiated wheat. Sufficient quantities of wheat were irradiated to permit analyses of samples after different periods of time had elapsed. The analytical values were found to vary with dose, marked differences (with respect to the control sample) being noted in the texture, odour, colour and taste of bread made with wheat that had received the highest doses. To determine changes in nutritional value the irradiated wheat was included in the diet of rats, both immediately following irradiation and

  18. Functionalization of silicon nanowires by conductive and non-conductive polymers

    Science.gov (United States)

    Belhousse, S.; Tighilt, F.-Z.; Sam, S.; Lasmi, K.; Hamdani, K.; Tahanout, L.; Megherbi, F.; Gabouze, N.

    2017-11-01

    The work reports on the development of hybrid devices based on silicon nanowires (SiNW) with polymers and the difference obtained when using conductive and non-conductive polymers. SiNW have attracted much attention due to their importance in understanding the fundamental properties at low dimensionality as well as their potential application in nanoscale devices as in field effect transistors, chemical or biological sensors, battery electrodes and photovoltaics. SiNW arrays were formed using metal assisted chemical etching method. This process is simple, fast and allows obtaining a wide range of silicon nanostructures. Hydrogen-passivated SiNW surfaces show relatively poor stability. Surface modification with organic species confers the desired stability and enhances the surface properties. For this reason, this work proposes a covalent grafting of organic material onto SiNW surface. We have chosen a non-conductive polymer polyvinylpyrrolidone (PVP) and conductive polymers polythiophene (PTh) and polypyrrole (PPy), in order to evaluate the electric effect of the polymers on the obtained materials. The hybrid structures were elaborated by the polymerization of the corresponding conjugated monomers by electrochemical route; this electropolymerization offers several advantages such as simplicity and rapidity. SiNW functionalization by conductive polymers has shown to have a huge effect on the electrical mobility. Hybrid surface morphologies were characterized by scanning electron microscopy (SEM), infrared spectroscopy (FTIR-ATR) and contact angle measurements.

  19. Combustion behaviour of ultra clean coal obtained by chemical demineralisation

    Energy Technology Data Exchange (ETDEWEB)

    F. Rubiera; A. Arenillas; B. Arias; J.J. Pis; I. Suarez-Ruiz; K.M. Steel; J.W. Patrick [Instituto Nacional del Carbon, CSIC, Oviedo (Spain)

    2003-10-01

    The increasing environmental concern caused by the use of fossil fuels and the concomitant need for improved combustion efficiency is leading to the development of new coal cleaning and utilisation processes. However, the benefits achieved by the removal of most mineral matter from coal either by physical or chemical methods can be annulled if poor coal combustibility characteristics are attained. In this work a high volatile bituminous coal with 6% ash content was subjected to chemical demineralisation via hydrofluoric and nitric acid leaching, the ash content of the clean coal was reduced to 0.3%. The original and treated coals were devolatilised in a drop tube furnace and the structure and morphology of the resultant chars was analysed by optical and scanning electron microscopies. The reactivity characteristics of the chars were studied by isothermal combustion tests in air at different temperatures in a thermogravimetric system. Comparison of the combustion behaviour and pollutant emissions of both coals was conducted in a drop tube furnace operating at 1000{sup o}C. The results of this work indicate that the char obtained from the chemically treated coal presents very different structure, morphology and reactivity behaviour than the char from the original coal. The changes induced by the chemical treatment increased the combustion efficiency determined in the drop tube furnace, in fact higher burnout levels were obtained for the demineralised coal.

  20. Nonlinear dynamics in cardiac conduction

    Science.gov (United States)

    Kaplan, D. T.; Smith, J. M.; Saxberg, B. E.; Cohen, R. J.

    1988-01-01

    Electrical conduction in the heart shows many phenomena familiar from nonlinear dynamics. Among these phenomena are multiple basins of attraction, phase locking, and perhaps period-doubling bifurcations and chaos. We describe a simple cellular-automation model of electrical conduction which simulates normal conduction patterns in the heart as well as a wide range of disturbances of heart rhythm. In addition, we review the application of percolation theory to the analysis of the development of complex, self-sustaining conduction patterns.