WorldWideScience

Sample records for chemical reactivity test

  1. Chemical Reactivity Test (CRT)

    Energy Technology Data Exchange (ETDEWEB)

    Zaka, F. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2016-12-13

    The Chemical Reactivity Test (CRT) is used to determine the thermal stability of High Explosives (HEs) and chemical compatibility between (HEs) and alien materials. The CRT is one of the small-scale safety tests performed on HE at the High Explosives Applications Facility (HEAF).

  2. Chemical Characterization and Reactivity Testing of Fuel-Oxidizer Reaction Product (Test Report)

    Science.gov (United States)

    1996-01-01

    The product of incomplete reaction of monomethylhydrazine (MMH) and nitrogen tetroxide (NTO) propellants, or fuel-oxidizer reaction product (FORP), has been hypothesized as a contributory cause of an anomaly which occurred in the chamber pressure (PC) transducer tube on the Reaction Control Subsystem (RCS) aft thruster 467 on flight STS-51. A small hole was found in the titanium-alloy PC tube at the first bend below the pressure transducer. It was surmised that the hole may have been caused by heat and pressure resulting from ignition of FORP. The NASA Johnson Space Center (JSC) White Sands Test Facility (WSTF) was requested to define the chemical characteristics of FORP, characterize its reactivity, and simulate the events in a controlled environment which may have lead to the Pc-tube failure. Samples of FORP were obtained from the gas-phase reaction of MMH with NTO under laboratory conditions, the pulsed firings of RCS thrusters with modified PC tubes using varied oxidizer or fuel lead times, and the nominal RCS thruster firings at WSTF and Kaiser-Marquardt. Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), accelerating rate calorimetry (ARC), ion chromatography (IC), inductively coupled plasma (ICP) spectrometry, thermogravimetric analysis (TGA) coupled to FTIR (TGA/FTIR), and mechanical impact testing were used to qualitatively and quantitatively characterize the chemical, thermal, and ignition properties of FORP. These studies showed that the composition of FORP is variable but falls within a limited range of compositions that depends on the fuel loxidizer ratio at the time of formation, composition of the post-formation atmosphere (reducing or oxidizing), and reaction or postreaction temperature. A typical composition contains methylhydrazinium nitrate (MMHN), ammonium nitrate (AN), methylammonium nitrate (MAN), and trace amounts of hydrazinium nitrate and 1,1-dimethylhydrazinium nitrate. The thermal decomposition

  3. Chemical Reactivity Testing for the National Spent Nuclear Fuel Program. Quality Assurance Project Plan

    International Nuclear Information System (INIS)

    Newsom, H.C.

    1999-01-01

    This quality assurance project plan (QAPjP) summarizes requirements used by Lockheed Martin Energy Systems, Incorporated (LMES) Development Division at Y-12 for conducting chemical reactivity testing of Department of Energy (DOE) owned spent nuclear fuel, sponsored by the National Spent Nuclear Fuel Program (NSNFP). The requirements are based on the NSNFP Statement of Work PRO-007 (Statement of Work for Laboratory Determination of Uranium Hydride Oxidation Reaction Kinetics.) This QAPjP will utilize the quality assurance program at Y-12, QA-101PD, revision 1, and existing implementing procedures for the most part in meeting the NSNFP Statement of Work PRO-007 requirements, exceptions will be noted

  4. Reactive chemicals and process hazards

    International Nuclear Information System (INIS)

    Surianarayanan, M.

    2016-01-01

    Exothermic chemical reactions are often accompanied by significant heat release, and therefore, need a thorough investigation before they are taken to a plant scale. Sudden thermal energy releases from exothermic decompositions and runaway reactions have contributed to serious fire and explosions in several chemical process plants. Similarly, thermal runaway had also occurred in storage and transportation of reactive chemicals. The secondary events of thermal runaway reactions can be rupture of process vessel, toxic spills and release of explosive vapor clouds or combination of these also. The explosion hazards are governed by the system thermodynamics and kinetics of the thermal process. Theoretical prediction of limiting temperature is difficult due to process complexities. Further, the kinetic data obtained through classical techniques, at conditions far away from runaway situation, is often not valid for assessing the runaway behavior of exothermic processes. The main focus of this lecture is to discuss the causes and several contributing factors for thermal runaway and instability and present analyses of the methodologies of the new instrumental techniques for assessing the thermal hazards of reactive chemicals during processing, storage and transportation. (author)

  5. Rock fracture processes in chemically reactive environments

    Science.gov (United States)

    Eichhubl, P.

    2015-12-01

    Rock fracture is traditionally viewed as a brittle process involving damage nucleation and growth in a zone ahead of a larger fracture, resulting in fracture propagation once a threshold loading stress is exceeded. It is now increasingly recognized that coupled chemical-mechanical processes influence fracture growth in wide range of subsurface conditions that include igneous, metamorphic, and geothermal systems, and diagenetically reactive sedimentary systems with possible applications to hydrocarbon extraction and CO2 sequestration. Fracture processes aided or driven by chemical change can affect the onset of fracture, fracture shape and branching characteristics, and fracture network geometry, thus influencing mechanical strength and flow properties of rock systems. We are investigating two fundamental modes of chemical-mechanical interactions associated with fracture growth: 1. Fracture propagation may be aided by chemical dissolution or hydration reactions at the fracture tip allowing fracture propagation under subcritical stress loading conditions. We are evaluating effects of environmental conditions on critical (fracture toughness KIc) and subcritical (subcritical index) fracture properties using double torsion fracture mechanics tests on shale and sandstone. Depending on rock composition, the presence of reactive aqueous fluids can increase or decrease KIc and/or subcritical index. 2. Fracture may be concurrent with distributed dissolution-precipitation reactions in the hostrock beyond the immediate vicinity of the fracture tip. Reconstructing the fracture opening history recorded in crack-seal fracture cement of deeply buried sandstone we find that fracture length growth and fracture opening can be decoupled, with a phase of initial length growth followed by a phase of dominant fracture opening. This suggests that mechanical crack-tip failure processes, possibly aided by chemical crack-tip weakening, and distributed solution-precipitation creep in the

  6. Patch testing with a new fragrance mix - reactivity to the individual constituents and chemical detection in relevant cosmetic products.

    Science.gov (United States)

    Frosch, Peter J; Rastogi, Suresh C; Pirker, Claudia; Brinkmeier, Thomas; Andersen, Klaus E; Bruze, Magnus; Svedman, Cecilia; Goossens, An; White, Ian R; Uter, Wolfgang; Arnau, Elena Giménez; Lepoittevin, Jean-Pierre; Johansen, Jeanne Duus; Menne, Torkil

    2005-04-01

    A new fragrance mix (FM II), with 6 frequently used chemicals not present in the currently used fragrance mix (FM I), was evaluated in 6 dermatological centres in Europe, as previously reported. In this publication, test results with the individual constituents and after repeated open application test (ROAT) of FM II are described. Furthermore, cosmetic products which had caused a contact dermatitis in patients were analysed for the presence of the individual constituents. In 1701 patients, the individual constituents of the medium (14%) and the highest (28%) concentration of FM II were simultaneously applied with the new mix at 3 concentrations (break-down testing for the lowest concentration of FM II (2.8%) was performed only if the mix was positive). ROAT was performed with the concentration of the FM II which had produced a positive or doubtful (+ or ?+) patch test reaction. Patients' products were analysed for the 6 target compounds by gas chromatography-mass spectrometry (GC-MS). 50 patients (2.9%) showed a positive reaction to 14% FM II and 70 patients (4.1%) to 28% FM II. 24/50 (48%) produced a positive reaction to 1 or more of the individual constituents of 14% FM II and 38/70 (54.3%) to 28% FM II, respectively. If doubtful reactions to individual constituents are included, the break-down testing was positive in 74% and 70%, respectively. Patients with a positive reaction to 14% FM II showed a higher rate of reactions to the individual constituent of the 28% FM II: 36/50 (72%). Positive reactions to individual constituents in patients negative to FM II were exceedingly rare. If doubtful reactions are regarded as negative, the sensitivity, specificity, positive predictive value and negative predictive value for the medium concentration of FM II towards at least 1 individual constituent was 92.3% (exact 95% confidence interval 74.9-99.1%), 98.4% (97.7-99.0%), 48% (33.7-62.6%) and 99.9% (99.6-"100.0%), respectively. For the high concentration, the figures

  7. Steam-chemical reactivity for irradiated beryllium

    Energy Technology Data Exchange (ETDEWEB)

    Anderl, R.A.; McCarthy, K.A.; Oates, M.A.; Petti, D.A.; Pawelko, R.J.; Smolik, G.R. [Idaho National Engineering and Environmental Lab., Idaho Falls, ID (United States)

    1998-01-01

    This paper reports the results of an experimental investigation to determine the influence of neutron irradiation effects and annealing on the chemical reactivity of beryllium exposed to steam. The work entailed measurements of the H{sub 2} generation rates for unirradiated and irradiated Be and for irradiated Be that had been previously annealed at different temperatures ranging from 450degC to 1200degC. H{sub 2} generation rates were similar for irradiated and unirradiated Be in steam-chemical reactivity experiments at temperatures between 450degC and 600degC. For irradiated Be exposed to steam at 700degC, the chemical reactivity accelerated rapidly and the specimen experienced a temperature excursion. Enhanced chemical reactivity at temperatures between 400degC and 600degC was observed for irradiated Be annealed at temperatures of 700degC and higher. This reactivity enhancement could be accounted for by the increased specific surface area resulting from development of a surface-connected porosity in the irradiated-annealed Be. (author)

  8. Chemical reactivity of cation-exchanged zeolites

    OpenAIRE

    Pidko, E.A.

    2008-01-01

    Zeolites modified with metal cations have been extensively studied during the last two decades because of their wide application in different technologically important fields such as catalysis, adsorption and gas separation. Contrary to the well-understood mechanisms of chemical reactions catalyzed by Brønsted acid sites in the hydrogen forms of zeolites, the nature of chemical reactivity, and related, the structure of the metal-containing ions in cation-exchanged zeolites remains the subject...

  9. Patch testing with a new fragrance mix - reactivity to the individual constituents and chemical detection in relevant cosmetic products

    DEFF Research Database (Denmark)

    Frosch, Peter J; Rastogi, Suresh C; Pirker, Claudia

    2005-01-01

    order was the same for both FM II concentrations: hydroxyisohexyl 3-cyclohexene carboxaldehyde (Lyral) > citral > farnesol > citronellol > alpha-hexyl-cinnamic aldehyde (AHCA). No unequivocally positive reaction to coumarin was observed. Lyral) was the dominant individual constituent, with positive...... and a positive reaction to either 28% or 14% FM II but a negative reaction to FM I. Analysis with GC-MS in a total of 24 products obtained from 12 patients showed at least 1-5 individual constituents per product: Lyral (79.2%), citronellol (87.5%), AHCA (58.3%), citral (50%) and coumarin (50%). The patients were...... patch test positive to Lyral, citral and AHCA. In conclusion, patients with a certain fragrance history and a negative reaction to FM I can be identified by FM II. Testing with individual constituents is positive in about 50% of cases reacting to either 14% or 28% FM II....

  10. Modeling food matrix effects on chemical reactivity: Challenges and perspectives.

    Science.gov (United States)

    Capuano, Edoardo; Oliviero, Teresa; van Boekel, Martinus A J S

    2017-06-29

    The same chemical reaction may be different in terms of its position of the equilibrium (i.e., thermodynamics) and its kinetics when studied in different foods. The diversity in the chemical composition of food and in its structural organization at macro-, meso-, and microscopic levels, that is, the food matrix, is responsible for this difference. In this viewpoint paper, the multiple, and interconnected ways the food matrix can affect chemical reactivity are summarized. Moreover, mechanistic and empirical approaches to explain and predict the effect of food matrix on chemical reactivity are described. Mechanistic models aim to quantify the effect of food matrix based on a detailed understanding of the chemical and physical phenomena occurring in food. Their applicability is limited at the moment to very simple food systems. Empirical modeling based on machine learning combined with data-mining techniques may represent an alternative, useful option to predict the effect of the food matrix on chemical reactivity and to identify chemical and physical properties to be further tested. In such a way the mechanistic understanding of the effect of the food matrix on chemical reactions can be improved.

  11. Phase equilibria in chemical reactive fluid mixtures

    International Nuclear Information System (INIS)

    Maurer, Gerd

    2011-01-01

    Downstream processing is a major part of nearly all processes in the chemical industries. Most separation processes in the chemical (and related) industries for fluid mixtures are based on phase equilibrium phenomena. The majority of separation processes can be modelled assuming that chemical reactions are of no (or very minor) importance, i.e., assuming that the overall speciation remains unchanged during a separation process. However, there are also a large number of industrially important processes where the thermodynamic properties are influenced by chemical reactions. The phase equilibrium of chemical reactive mixtures has been a major research area of the author's group over nearly 40 years. In this contribution, three examples from that research are discussed. The first example deals with the vapour phase dimerisation of carboxylic acids and its consequences on phase equilibrium phenomena and phase equilibrium predictions. The second example deals with the solubility of sour gases (e.g., carbon dioxide and sulfur dioxide) in aqueous solutions of ammonia. That topic has been of interest for many years, e.g., in relation with the gasification and liquefaction of coal and, more recently, with the removal of carbon dioxide from flue gas in the 'chilled ammonia process'. The third example deals with phase equilibrium phenomena in aqueous solutions of polyelectrolytes. It deals with the phenomenon of 'counter ion condensation' and methods to model the Gibbs free energy of such solutions.

  12. An autonomous organic reaction search engine for chemical reactivity

    Science.gov (United States)

    Dragone, Vincenza; Sans, Victor; Henson, Alon B.; Granda, Jaroslaw M.; Cronin, Leroy

    2017-06-01

    The exploration of chemical space for new reactivity, reactions and molecules is limited by the need for separate work-up-separation steps searching for molecules rather than reactivity. Herein we present a system that can autonomously evaluate chemical reactivity within a network of 64 possible reaction combinations and aims for new reactivity, rather than a predefined set of targets. The robotic system combines chemical handling, in-line spectroscopy and real-time feedback and analysis with an algorithm that is able to distinguish and select the most reactive pathways, generating a reaction selection index (RSI) without need for separate work-up or purification steps. This allows the automatic navigation of a chemical network, leading to previously unreported molecules while needing only to do a fraction of the total possible reactions without any prior knowledge of the chemistry. We show the RSI correlates with reactivity and is able to search chemical space using the most reactive pathways.

  13. Chemical Reactivity as Described by Quantum Chemical Methods

    Directory of Open Access Journals (Sweden)

    F. De Proft

    2002-04-01

    Full Text Available Abstract: Density Functional Theory is situated within the evolution of Quantum Chemistry as a facilitator of computations and a provider of new, chemical insights. The importance of the latter branch of DFT, conceptual DFT is highlighted following Parr's dictum "to calculate a molecule is not to understand it". An overview is given of the most important reactivity descriptors and the principles they are couched in. Examples are given on the evolution of the structure-property-wave function triangle which can be considered as the central paradigm of molecular quantum chemistry to (for many purposes a structure-property-density triangle. Both kinetic as well as thermodynamic aspects can be included when further linking reactivity to the property vertex. In the field of organic chemistry, the ab initio calculation of functional group properties and their use in studies on acidity and basicity is discussed together with the use of DFT descriptors to study the kinetics of SN2 reactions and the regioselectivity in Diels Alder reactions. Similarity in reactivity is illustrated via a study on peptide isosteres. In the field of inorganic chemistry non empirical studies of adsorption of small molecules in zeolite cages are discussed providing Henry constants and separation constants, the latter in remarkable good agreement with experiments. Possible refinements in a conceptual DFT context are presented. Finally an example from biochemistry is discussed : the influence of point mutations on the catalytic activity of subtilisin.

  14. Parameters estimation for reactive transport: A way to test the validity of a reactive model

    Science.gov (United States)

    Aggarwal, Mohit; Cheikh Anta Ndiaye, Mame; Carrayrou, Jérôme

    The chemical parameters used in reactive transport models are not known accurately due to the complexity and the heterogeneous conditions of a real domain. We will present an efficient algorithm in order to estimate the chemical parameters using Monte-Carlo method. Monte-Carlo methods are very robust for the optimisation of the highly non-linear mathematical model describing reactive transport. Reactive transport of tributyltin (TBT) through natural quartz sand at seven different pHs is taken as the test case. Our algorithm will be used to estimate the chemical parameters of the sorption of TBT onto the natural quartz sand. By testing and comparing three models of surface complexation, we show that the proposed adsorption model cannot explain the experimental data.

  15. Reactivity of Dual-Use Decontaminants with Chemical Warfare Agents

    Science.gov (United States)

    2016-07-01

    REACTIVITY OF DUAL-USE DECONTAMINANTS WITH CHEMICAL WARFARE AGENTS ECBC-TR-1384... Decontaminants with Chemical Warfare Agents 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) Willis, Matthew P...extraction) of chemical warfare agents from materials. 15. SUBJECT TERMS GD HD Decontamination Hazard mitigation VX Chemical warfare agent Liquid-phase

  16. Nondestructive Reactivation of Chemical Protective Garments

    National Research Council Canada - National Science Library

    Chang, Kuo

    1995-01-01

    .... Complete reactivation was achieved when the aqueous/ i-propanol/ iodine displacement method of Manes, which removed all but pure hydrocarbon oil soils from the current overgarment Type III foam...

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

    NARCIS (Netherlands)

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

    1997-01-01

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

  18. Chemical reactor modeling multiphase reactive flows

    CERN Document Server

    Jakobsen, Hugo A

    2014-01-01

    Chemical Reactor Modeling closes the gap between Chemical Reaction Engineering and Fluid Mechanics.  The second edition consists of two volumes: Volume 1: Fundamentals. Volume 2: Chemical Engineering Applications In volume 1 most of the fundamental theory is presented. A few numerical model simulation application examples are given to elucidate the link between theory and applications. In volume 2 the chemical reactor equipment to be modeled are described. Several engineering models are introduced and discussed. A survey of the frequently used numerical methods, algorithms and schemes is provided. A few practical engineering applications of the modeling tools are presented and discussed. The working principles of several experimental techniques employed in order to get data for model validation are outlined. The monograph is based on lectures regularly taught in the fourth and fifth years graduate courses in transport phenomena and chemical reactor modeling, and in a post graduate course in modern reactor m...

  19. Test Pile Reactivity Loss Due to Trichloroethylene

    International Nuclear Information System (INIS)

    Plumlee, K.E.

    2001-01-01

    The presence of trichloroethylene in the test pile caused a continual decrease in pile reactivity. A system which removed, purified, and returned 12,000 cfh helium to the pile has held contamination to a negligible level and has permitted normal pile operation

  20. Chemical reactivity of cation-exchanged zeolites

    NARCIS (Netherlands)

    Pidko, E.A.

    2008-01-01

    Zeolites modified with metal cations have been extensively studied during the last two decades because of their wide application in different technologically important fields such as catalysis, adsorption and gas separation. Contrary to the well-understood mechanisms of chemical reactions catalyzed

  1. Chemical reactivities of some interstellar molecules

    Energy Technology Data Exchange (ETDEWEB)

    Chadha, M S

    1980-01-01

    Work in the area of chemical evolution during the last 25 years has revealed the formation of a large number of biologically important molecules produced from simple starting materials under relatively simple experimental conditions. Much of this work has resulted from studies under atmospheres simulating that of the primitive earth or other planets. During the last decade, progress has also been made in the identification of chemical constituents of interstellar medium. A number of these molecules are the same as those identified in laboratory experiments. Even though the conditions of the laboratory experiments are vastly different from those of the cool, low-density interstellar medium, some of the similarities in composition are too obvious to go unnoticed. The present paper highlights some of the similarities in the composition of prebiotic molecules and those discovered in the interstellar medium. Also the chemical reactions which some of the common molecules e.g., NH3, HCN, H2CO, HC(triple bond)-C-CN etc. can undergo are surveyed.

  2. Slow Invariant Manifolds in Chemically Reactive Systems

    Science.gov (United States)

    Paolucci, Samuel; Powers, Joseph M.

    2006-11-01

    The scientific design of practical gas phase combustion devices has come to rely on the use of mathematical models which include detailed chemical kinetics. Such models intrinsically admit a wide range of scales which renders their accurate numerical approximation difficult. Over the past decade, rational strategies, such as Intrinsic Low Dimensional Manifolds (ILDM) or Computational Singular Perturbations (CSP), for equilibrating fast time scale events have been successfully developed, though their computation can be challenging and their accuracy in most cases uncertain. Both are approximations to the preferable slow invariant manifold which best describes how the system evolves in the long time limit. Strategies for computing the slow invariant manifold are examined, and results are presented for practical combustion systems.

  3. Study on chemical reactivity control of liquid sodium. Research program

    International Nuclear Information System (INIS)

    Saito, Jun-ichi; Ara, Kuniaki; Sugiyama, Ken-ichiro; Kitagawa, Hiroshi; Oka, Nobuki; Yoshioka, Naoki

    2007-01-01

    Liquid sodium has the excellent properties as coolant of the fast breeder reactor (FBR). On the other hand, it reacts high with water and oxygen. So an innovative technology to suppress the reactivity is desired. The purpose of this study is to control the chemical reactivity of liquid sodium by dispersing the nanometer-size metallic particles (we call them Nano-particles) into liquid sodium. We focus on the atomic interaction between Nano-particles and sodium atoms. And we try to apply it to suppress the chemical reactivity of liquid sodium. Liquid sodium dispersing Nano-particles is named 'Nano-fluid'. Research programs of this study are the Nano-particles production, the evaluation of reactivity suppression of liquid sodium and the feasibility study to FBR plant. In this paper, the research programs and status are described. The important factors for particle production were understood. In order to evaluate the chemical reactivity of Nano-fluid the research programs were planned. The feasibility of the application of Nano-fluid to the coolant of FBR plant was evaluated preliminarily from the viewpoint of design and operation. (author)

  4. Local Chemical Reactivity of a Metal Alloy Surface

    DEFF Research Database (Denmark)

    Hammer, Bjørk; Scheffler, Matthias

    1995-01-01

    The chemical reactivity of a metal alloy surface is studied by density functional theory investigating the interaction of H2 with NiAl(110). The energy barrier for H2 dissociation is largely different over the Al and Ni sites without, however, reflecting the barriers over the single component metal...

  5. Revisiting the chemical reactivity indices as the state function derivatives. The role of classical chemical hardness

    Energy Technology Data Exchange (ETDEWEB)

    Malek, Ali; Balawender, Robert, E-mail: rbalawender@ichf.edu.pl [Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, PL-01-224 Warsaw (Poland)

    2015-02-07

    The chemical reactivity indices as the equilibrium state-function derivatives are revisited. They are obtained in terms of the central moments (fluctuation formulas). To analyze the role of the chemical hardness introduced by Pearson [J. Am. Chem. Soc. 105, 7512 (1983)], the relations between the derivatives up to the third-order and the central moments are obtained. As shown, the chemical hardness and the chemical potential are really the principal indices of the chemical reactivity theory. It is clear from the results presented here that the chemical hardness is not the derivative of the Mulliken chemical potential (this means also not the second derivative of the energy at zero-temperature limit). The conventional quadratic dependence of energy, observed at finite temperature, reduces to linear dependence on the electron number at zero-temperature limit. The chemical hardness plays a double role in the admixture of ionic states to the reference neutral state energy: it determines the amplitude of the admixture and regulates the damping of its thermal factor.

  6. Revisiting the chemical reactivity indices as the state function derivatives. The role of classical chemical hardness

    International Nuclear Information System (INIS)

    Malek, Ali; Balawender, Robert

    2015-01-01

    The chemical reactivity indices as the equilibrium state-function derivatives are revisited. They are obtained in terms of the central moments (fluctuation formulas). To analyze the role of the chemical hardness introduced by Pearson [J. Am. Chem. Soc. 105, 7512 (1983)], the relations between the derivatives up to the third-order and the central moments are obtained. As shown, the chemical hardness and the chemical potential are really the principal indices of the chemical reactivity theory. It is clear from the results presented here that the chemical hardness is not the derivative of the Mulliken chemical potential (this means also not the second derivative of the energy at zero-temperature limit). The conventional quadratic dependence of energy, observed at finite temperature, reduces to linear dependence on the electron number at zero-temperature limit. The chemical hardness plays a double role in the admixture of ionic states to the reference neutral state energy: it determines the amplitude of the admixture and regulates the damping of its thermal factor

  7. To Model Chemical Reactivity in Heterogeneous Emulsions, Think Homogeneous Microemulsions.

    Science.gov (United States)

    Bravo-Díaz, Carlos; Romsted, Laurence Stuart; Liu, Changyao; Losada-Barreiro, Sonia; Pastoriza-Gallego, Maria José; Gao, Xiang; Gu, Qing; Krishnan, Gunaseelan; Sánchez-Paz, Verónica; Zhang, Yongliang; Dar, Aijaz Ahmad

    2015-08-25

    Two important and unsolved problems in the food industry and also fundamental questions in colloid chemistry are how to measure molecular distributions, especially antioxidants (AOs), and how to model chemical reactivity, including AO efficiency in opaque emulsions. The key to understanding reactivity in organized surfactant media is that reaction mechanisms are consistent with a discrete structures-separate continuous regions duality. Aggregate structures in emulsions are determined by highly cooperative but weak organizing forces that allow reactants to diffuse at rates approaching their diffusion-controlled limit. Reactant distributions for slow thermal bimolecular reactions are in dynamic equilibrium, and their distributions are proportional to their relative solubilities in the oil, interfacial, and aqueous regions. Our chemical kinetic method is grounded in thermodynamics and combines a pseudophase model with methods for monitoring the reactions of AOs with a hydrophobic arenediazonium ion probe in opaque emulsions. We introduce (a) the logic and basic assumptions of the pseudophase model used to define the distributions of AOs among the oil, interfacial, and aqueous regions in microemulsions and emulsions and (b) the dye derivatization and linear sweep voltammetry methods for monitoring the rates of reaction in opaque emulsions. Our results show that this approach provides a unique, versatile, and robust method for obtaining quantitative estimates of AO partition coefficients or partition constants and distributions and interfacial rate constants in emulsions. The examples provided illustrate the effects of various emulsion properties on AO distributions such as oil hydrophobicity, emulsifier structure and HLB, temperature, droplet size, surfactant charge, and acidity on reactant distributions. Finally, we show that the chemical kinetic method provides a natural explanation for the cut-off effect, a maximum followed by a sharp reduction in AO efficiency with

  8. Automated reactivity anomaly surveillance in the Fast Flux Test Facility

    International Nuclear Information System (INIS)

    Knutson, B.J.; Harris, R.A.; Honeyman, D.J.; Shook, A.T.; Krohn, C.N.

    1985-01-01

    The automated technique for monitoring core reactivity during power operation used at the Fast Flux Test Facility (FFTF) is described. This technique relies on comparing predicted to measured rod positions to detect any anomalous (or unpredicted) core reactivity changes. It is implemented on the Plant Data System (PDS) computer and, thus, provides rapid indication of any abnormal core conditions. The prediction algorithms use thermal-hydraulic, control rod position and neutron flux sensor information to predict the core reactivity state

  9. Local chemical potential, local hardness, and dual descriptors in temperature dependent chemical reactivity theory.

    Science.gov (United States)

    Franco-Pérez, Marco; Ayers, Paul W; Gázquez, José L; Vela, Alberto

    2017-05-31

    In this work we establish a new temperature dependent procedure within the grand canonical ensemble, to avoid the Dirac delta function exhibited by some of the second order chemical reactivity descriptors based on density functional theory, at a temperature of 0 K. Through the definition of a local chemical potential designed to integrate to the global temperature dependent electronic chemical potential, the local chemical hardness is expressed in terms of the derivative of this local chemical potential with respect to the average number of electrons. For the three-ground-states ensemble model, this local hardness contains a term that is equal to the one intuitively proposed by Meneses, Tiznado, Contreras and Fuentealba, which integrates to the global hardness given by the difference in the first ionization potential, I, and the electron affinity, A, at any temperature. However, in the present approach one finds an additional temperature-dependent term that introduces changes at the local level and integrates to zero. Additionally, a τ-hard dual descriptor and a τ-soft dual descriptor given in terms of the product of the global hardness and the global softness multiplied by the dual descriptor, respectively, are derived. Since all these reactivity indices are given by expressions composed of terms that correspond to products of the global properties multiplied by the electrophilic or nucleophilic Fukui functions, they may be useful for studying and comparing equivalent sites in different chemical environments.

  10. Enhancing the design of in situ chemical barriers with multicomponent reactive transport modeling

    International Nuclear Information System (INIS)

    Sevougian, S.D.; Steefel, C.I.; Yabusaki, S.B.

    1994-11-01

    This paper addresses the need for systematic control of field-scale performance in the emplacement and operation of in situ chemical treatment barriers; in particular, it addresses the issue of how the local coupling of reaction kinetics and material heterogeneities at the laboratory or bench scale can be accurately upscaled to the field. The authors have recently developed modeling analysis tools that can explicitly account for all relevant chemical reactions that accompany the transport of reagents and contaminants through a chemically and physically heterogeneous subsurface rock or soil matrix. These tools are incorporated into an enhanced design methodology for in situ chemical treatment technologies, and the new methodology is demonstrated in the ongoing design of a field experiment for the In Situ Redox Manipulation (ISRM) project at the U.S. Department of Energy (DOE) Hanford Site. The ISRM design approach, which systematically integrates bench-scale and site characterization information, provides an ideal test for the new reactive transport techniques. The need for the enhanced chemistry capability is demonstrated by an example that shows how intra-aqueous redox kinetics can affect the transport of reactive solutes. Simulations are carried out on massively parallel computer architectures to resolve the influence of multiscale heterogeneities on multicomponent, multidimensional reactive transport. The technology will soon be available to design larger-scale remediation schemes

  11. An experimental study of steam explosions involving chemically reactive metal

    International Nuclear Information System (INIS)

    Cho, D.H.; Armstrong, D.R.; Gunther, W.H.; Basu, S.

    1997-01-01

    An experimental study of molten zirconium-water explosions was conducted. A 1-kg mass of zirconium melt was dropped into a column of water. Explosions took place only when an external trigger was used. In the triggered tests, the extent of oxidation of the zirconium melt was very extensive. However, the explosion energetics estimated were found to be very small compared to the potential chemical energy available from the oxidation reaction. Zirconium is of particular interest, since it is a component of the core materials of the current nuclear power reactors. This paper describes the test apparatus and summarizes the results of four tests conducted using pure zirconium melt

  12. Reactivity anomalies in the FFTF [Fast Flux Test Facility

    International Nuclear Information System (INIS)

    Knutson, B.J.; Harris, R.A.

    1987-04-01

    Experience using an automated core reactivity monitoring technique at the Fast Flux Test Facility (FFTF) through eight operating cycles is described. This technique relies on comparing predicted to measured rod positions to detect any anomalous (or unpredicted) core reactivity changes. Reactivity worth predictions of core state changes (e.g., temperature and irradiation changes) and compensating control rod movements are required for the rod position comparison. A substantial data base now exists to evaluate changes in temperature reactivity feedback effects operational in the FFTF, rod worth changes due to core loading, temperature and irradiation effects and burnup effects associated with transmutation of fuel materials. This report summarizes preliminary work of correlating zero power and at-power rod worth measurement data, calculated burnup rates and rod worths using the latest ENDF/B-V cross section set for each cycle to evaluate the prediction models and attempt to resolve observed reactivity anomalies. 2 figs., 2 tabs

  13. Reactive solute transport in physically and chemically heterogeneous porous media with multimodal reactive mineral facies: the Lagrangian approach.

    Science.gov (United States)

    Soltanian, Mohamad Reza; Ritzi, Robert W; Dai, Zhenxue; Huang, Chao Cheng

    2015-03-01

    Physical and chemical heterogeneities have a large impact on reactive transport in porous media. Examples of heterogeneous attributes affecting reactive mass transport are the hydraulic conductivity (K), and the equilibrium sorption distribution coefficient (Kd). This paper uses the Deng et al. (2013) conceptual model for multimodal reactive mineral facies and a Lagrangian-based stochastic theory in order to analyze the reactive solute dispersion in three-dimensional anisotropic heterogeneous porous media with hierarchical organization of reactive minerals. An example based on real field data is used to illustrate the time evolution trends of reactive solute dispersion. The results show that the correlation between the hydraulic conductivity and the equilibrium sorption distribution coefficient does have a significant effect on reactive solute dispersion. The anisotropy ratio does not have a significant effect on reactive solute dispersion. Furthermore, through a sensitivity analysis we investigate the impact of changing the mean, variance, and integral scale of K and Kd on reactive solute dispersion. Copyright © 2014 Elsevier Ltd. All rights reserved.

  14. Attenuation of Chemical Reactivity of Shale Matrixes following Scale Precipitation

    Science.gov (United States)

    Li, Q.; Jew, A. D.; Kohli, A. H.; Alalli, G.; Kiss, A. M.; Kovscek, A. R.; Zoback, M. D.; Brown, G. E.; Maher, K.; Bargar, J.

    2017-12-01

    Introduction of fracture fluids into shales initiates a myriad of fluid-rock reactions that can strongly influence migration of fluid and hydrocarbon through shale/fracture interfaces. Due to the extremely low permeability of shale matrixes, studies on chemical reactivity of shales have mostly focused on shale surfaces. Shale-fluid interactions inside within shale matrixes have not been examined, yet the matrix is the primary conduit through which hydrocarbons and potential contaminants are transmitted. To characterize changes in matrix mineralogy, porosity, diffusivity, and permeability during hydraulic stimulation, we reacted Marcellus (high clay and low carbonate) and Eagle Ford (low clay and high carbonate) shale cores with fracture fluids for 3 weeks at elevated pressure and temperature (80 oC, and 77 bars). In the carbonate-poor Marcellus system, fluid pH increased from 2 to 4, and secondary Fe(OH)3 precipitates were observed in the fluid. Sulfur X-ray fluorescence maps show that fluids had saturated and reacted with the entire 1-cm-diameter core. In the carbonate-rich Eagle Ford system, pH increased from 2 to 6 due to calcite dissolution. When additional Ba2+ and SO42- were present (log10(Q/K)=1.3), extensive barite precipitation was observed in the matrix of the Eagle Ford core (and on the surface). Barite precipitation was also observed on the surface of the Marcellus core, although to a lesser extent. In the Marcellus system, the presence of barite scale attenuated diffusivity in the matrix, as demonstrated by sharply reduced Fe leaching and much less sulfide oxidation. Systematic studies in homogeneous solution show that barite scale precipitation rates are highly sensitive to pH, salinity, and the presence of organic compounds. These findings imply that chemical reactions are not confined to shale/fluid interfaces but can penetrate into shale matrices, and that barite scale formation can clog diffusion pathways for both fluid and hydrocarbon.

  15. Chemical stability of reactive skin decontamination lotion (RSDL®).

    Science.gov (United States)

    Bogan, R; Maas, H J; Zimmermann, T

    2018-09-01

    Reactive Skin Decontamination Lotion (RSDL ® ) is used for the decontamination of Chemical Warfare Agents and Toxic Industrial Compounds after dermal exposure. It has to be stockpiled over a long period and is handled in all climatic zones. Therefore stability is an essential matter of concern. In this work we describe a study to the chemical stability of RSDL ® as basis for an estimation of shelf life. We analysed RSDL ® for the active ingredient 2,3-butandione monoxime (diacetylmonooxime, DAM), the putative degradation product dimethylglyoxime (DMG) and unknown degradation products by means of a reversed phase high pressure liquid chromatography (HPLC). Calculations were done according to the Arrhenius equation. Based on the temperature dependent rate constants, the time span was calculated, until defined threshold values for DAM and DMG subject to specification and valid regulations were exceeded. The calculated data were compared to the ones gathered from stockpiled samples and samples exposed during foreign mission. The decline of DAM followed first order kinetics, while formation of DMG could be described by zero order kinetics. The rate constants were distinctively temperature dependent. Calculated data were in good accordance to the measured ones from stockpile and mission. Based on a specified acceptable DAM-content of 90% and a valid threshold value of 0.1% (w/w) for the degradation product DMG, RSDL ® proved to be stable for at least four years if stored at the recommended conditions of 15°C-30°C. If continuously stored at higher temperatures shelf life will decrease markedly. Therefore RSDL ® is an object for risk orientated quality monitoring during storage. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. Chemical compatibility screening test results

    International Nuclear Information System (INIS)

    Nigrey, P.J.; Dickens, T.G.

    1997-12-01

    A program for evaluating packaging components that may be used in transporting mixed-waste forms has been developed and the first phase has been completed. This effort involved the screening of ten plastic materials in four simulant mixed-waste types. These plastics were butadiene-acrylonitrile copolymer rubber, cross-linked polyethylene (XLPE), epichlorohydrin rubber, ethylene-propylene rubber (EPDM), fluorocarbon (Viton or Kel-F), polytetrafluoroethylene, high-density polyethylene (HDPE), isobutylene-isoprene copolymer rubber (butyl), polypropylene, and styrene-butadiene rubber (SBR). The selected simulant mixed wastes were (1) an aqueous alkaline mixture of sodium nitrate and sodium nitrite; (2) a chlorinated hydrocarbon mixture; (3) a simulant liquid scintillation fluid; and (4) a mixture of ketones. The testing protocol involved exposing the respective materials to 286,000 rads of gamma radiation followed by 14-day exposures to the waste types at 60 degrees C. The seal materials were tested using vapor transport rate (VTR) measurements while the liner materials were tested using specific gravity as a metric. For these tests, a screening criterion of 0.9 g/hr/m 2 for VTR and a specific gravity change of 10% was used. Based on this work, it was concluded that while all seal materials passed exposure to the aqueous simulant mixed waste, EPDM and SBR had the lowest VTRs. In the chlorinated hydrocarbon simulant mixed waste, only Viton passed the screening tests. In both the simulant scintillation fluid mixed waste and the ketone mixture simulant mixed waste, none of the seal materials met the screening criteria. For specific gravity testing of liner materials, the data showed that while all materials with the exception of polypropylene passed the screening criteria, Kel-F, HDPE, and XLPE offered the greatest resistance to the combination of radiation and chemicals

  17. A theory of chemicals regulation and testing

    NARCIS (Netherlands)

    Gabbert, S.G.M.; Weikard, H.P.

    2010-01-01

    Risk management of chemicals requires information about their adverse effects such as toxicity and persistence, for example. Testing of chemicals allows for improving the information base for regulatory decision-making on chemicals' production and use. Testing a large number of chemicals with

  18. Substrate Vibrations as Promoters of Chemical Reactivity on Metal Surfaces.

    Science.gov (United States)

    Campbell, Victoria L; Chen, Nan; Guo, Han; Jackson, Bret; Utz, Arthur L

    2015-12-17

    Studies exploring how vibrational energy (Evib) promotes chemical reactivity most often focus on molecular reagents, leaving the role of substrate atom motion in heterogeneous interfacial chemistry underexplored. This combined theoretical and experimental study of methane dissociation on Ni(111) shows that lattice atom motion modulates the reaction barrier height during each surface atom's vibrational period, which leads to a strong variation in the reaction probability (S0) with surface temperature (Tsurf). State-resolved beam-surface scattering studies at Tsurf = 90 K show a sharp threshold in S0 at translational energy (Etrans) = 42 kJ/mol. When Etrans decreases from 42 kJ/mol to 34 kJ/mol, S0 decreases 1000-fold at Tsurf = 90 K, but only 2-fold at Tsurf = 475 K. Results highlight the mechanism for this effect, provide benchmarks for DFT calculations, and suggest the potential importance of surface atom induced barrier height modulation in heterogeneously catalyzed reactions, particularly on structurally labile nanoscale particles and defect sites.

  19. Inorganic chemical composition and chemical reactivity of settled dust generated by the World Trade Center building collapse: Chapter 12

    Science.gov (United States)

    Plumlee, Geoffrey S.; Hageman, Philip L.; Lamothe, Paul J.; Ziegler, Thomas L.; Meeker, Gregory P.; Theodorakos, Peter M.; Brownfield, Isabelle; Adams, Monique G.; Swayze, Gregg A.; Hoefen, Todd M.; Taggart, Joseph E.; Clark, Roger N.; Wilson, S.; Sutley, Stephen J.

    2009-01-01

    Samples of dust deposited around lower Manhattan by the September 11, 2001, World Trade Center (WTC) collapse have inorganic chemical compositions that result in part from the variable chemical contributions of concrete, gypsum wallboard, glass fibers, window glass, and other materials contained in the buildings. The dust deposits were also modified chemically by variable interactions with rain water or water used in street washing and fire fighting. Chemical leach tests using deionized water as the extraction fluid show the dust samples can be quite alkaline, due primarily to reactions with calcium hydroxide in concrete particles. Calcium and sulfate are the most soluble components in the dust, but many other elements are also readily leached, including metals such as Al, Sb, Mo Cr, Cu, and Zn. Indoor dust samples produce leachates with higher pH, alkalinity, and dissolved solids than outdoor dust samples, suggesting most outdoor dust had reacted with water and atmospheric carbon dioxide prior to sample collection. Leach tests using simulated lung fluids as the extracting fluid suggest that the dust might also be quite reactive in fluids lining the respiratory tract, resulting in dissolution of some particles and possible precipitation of new phases such as phosphates, carbonates, and silicates. Results of these chemical characterization studies can be used by health scientists as they continue to track and interpret health effects resulting from the short-term exposure to the initial dust cloud and the longer-term exposure to dusts resuspended during cleanup.

  20. C-Reactive Protein (CRP) Test

    Science.gov (United States)

    ... can be caused by a number of different pathological conditions such as arthritis , lupus , or inflammatory bowel ... clinchem.org . Accessed October 2011. Lowry, F. (2010 March 23). CRP Test Guides Antibiotic Prescribing for Respiratory ...

  1. Natural history of skin prick test reactivity

    DEFF Research Database (Denmark)

    Schou Nielsen, Jesper; Meteran, Howraman; Ulrik, Charlotte Suppli

    2017-01-01

    population sample of children and adolescents in relation to symptoms of rhinitis. METHODS: A total of 983 individuals, aged 7 to 17 years, were randomly selected in 1986 and invited to 4 examinations during a 20-year period. During each examination, a skin prick test was performed using common local...

  2. Nickel patch test reactivity and the menstrual cycle

    DEFF Research Database (Denmark)

    Rohold, A E; Halkier-Sørensen, L; Thestrup-Pedersen, K

    1994-01-01

    Premenstrual exacerbation of allergic contact dermatitis and varying allergic patch test responses have been reported at different points of the period. Using a dilution series of nickel sulphate, we studied the variation in patch test reactivity in nickel allergic women in relation to the menstr......Premenstrual exacerbation of allergic contact dermatitis and varying allergic patch test responses have been reported at different points of the period. Using a dilution series of nickel sulphate, we studied the variation in patch test reactivity in nickel allergic women in relation...... were tested first on day 7-10 and the other half first on day 20-24. There was no difference in the degree of patch test reactivity, when the results from day 7-10 and day 20-24 were compared (p > 0.4). However, when we compared the patch test results from the first and second test procedure, we found...... of positive patch tests led to an increased skin reactivity towards the same allergen, when the patients were retested weeks later....

  3. Encoding of Fundamental Chemical Entities of Organic Reactivity Interest using chemical ontology and XML.

    Science.gov (United States)

    Durairaj, Vijayasarathi; Punnaivanam, Sankar

    2015-09-01

    Fundamental chemical entities are identified in the context of organic reactivity and classified as appropriate concept classes namely ElectronEntity, AtomEntity, AtomGroupEntity, FunctionalGroupEntity and MolecularEntity. The entity classes and their subclasses are organized into a chemical ontology named "ChemEnt" for the purpose of assertion, restriction and modification of properties through entity relations. Individual instances of entity classes are defined and encoded as a library of chemical entities in XML. The instances of entity classes are distinguished with a unique notation and identification values in order to map them with the ontology definitions. A model GUI named Entity Table is created to view graphical representations of all the entity instances. The detection of chemical entities in chemical structures is achieved through suitable algorithms. The possibility of asserting properties to the entities at different levels and the mechanism of property flow within the hierarchical entity levels is outlined. Copyright © 2015 Elsevier Inc. All rights reserved.

  4. Reactivity test between beryllium and copper

    International Nuclear Information System (INIS)

    Kawamura, H.; Kato, M.

    1995-01-01

    Beryllium has been expected for using as plasma facing material on ITER. And, copper alloy has been proposed as heat sink material behind plasma facing components. Therefore, both materials must be joined. However, the elementary process of reaction between beryllium and copper alloy does not clear in detail. For example, other authors reported that beryllium reacted with copper at high temperature, but it was not obvious about the generation of reaction products and increasing of the reaction layer. In the present work, from this point, for clarifying the elementary process of reaction between beryllium and copper, the out-of-pile compatibility tests were conducted with diffusion couples of beryllium and copper which were inserted in the capsule filled with high purity helium gas (6N). Annealing temperatures were 300, 400, 500, 600 and 700 degrees C, and annealing periods were 100, 300 and 1000h. Beryllium specimens were hot pressed beryllium, and copper specimens were OFC (Oxygen Free Copper)

  5. Sensitivity of BWR shutdown margin tests to local reactivity anomalies

    International Nuclear Information System (INIS)

    Cokinos, D.M.; Carew, J.F.

    1987-01-01

    Successful shutdown margin (SDM) demonstration is a required procedure in the startup of a newly configured boiling water reactor (BWR) core. In its most reactive condition throughout a cycle, a BWR core must be capable of being made subcritical by a specified margin with the highest worth control rod fully withdrawn and all other rods at their fully inserted positions. Two different methods are used to demonstrate SDM: (a) the adjacent-rod test and (b) the in-sequence test. In the adjacent-rod test, the strongest rod is fully withdrawn and an adjacent rod is withdrawn to reach criticality. In the in-sequence test, control rods spread throughout the core are withdrawn in a predetermined sequence of withdrawals. Larger than expected core k/sub eff/ values have been observed during the performance of BWR SDM tests. The purpose of the work summarized in this paper has been to investigated and quantify the sensitivity of both the adjacent-rod and in-sequence SDM tests to local reactivity anomalies. This was accomplished by introducing reactivity perturbations at selected four-bundle cell locations and by evaluating their effect on core reactivity in each of the two tests

  6. Variation in aluminium patch test reactivity over time.

    Science.gov (United States)

    Siemund, Ingrid; Mowitz, Martin; Zimerson, Erik; Bruze, Magnus; Hindsén, Monica

    2017-11-01

    Contact allergy to aluminium has been reported more frequently in recent years. It has been pointed out that positive patch test reactions to aluminium may not be reproducible on retesting. To investigate possible variations in patch test reactivity to aluminium over time. Twenty-one adults, who had previously reacted positively to aluminium, were patch tested with equimolar dilution series in pet. of aluminium chloride hexahydrate and aluminium lactate, four times over a period of 8 months. Thirty-six of 84 (43%) serial dilution tests with aluminium chloride hexahydrate and 49 of 84 (58%) serial dilution tests with aluminium lactate gave negative results. The range of reactivity varied between a negative reaction to aluminium chloride hexahydrate at 10% and/or to aluminium lactate at 12%, and a positive reaction to aluminium chloride hexahydrate at 0.1% and/or to aluminium lactate at 0.12%. The highest individual difference in test reactivity noticed was 320-fold when the two most divergent minimal eliciting concentrations were compared. The patch test reactivity to aluminium varies over time. Aluminium-allergic individuals may have false-negative reactions. Therefore, retesting with aluminium should be considered when there is a strong suspicion of aluminium contact allergy. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  7. Chemical reactivity of alkali lignin modified with laccase

    International Nuclear Information System (INIS)

    Sun, Yong; Qiu, Xueqing; Liu, Yunquan

    2013-01-01

    The modification of alkali lignin with laccase was investigated. The structural change of lignin was analyzed. The sulfonation reactivity was measured by the content of sulfonic group. The results showed the sulfonation reactivity increased to some extent under the condition of atmosphere pressure, but decreased under the condition of 0.3 MPa oxygen pressure. The analysis of Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR) and gel permeation chromatography (GPC) showed the cleavage of various ether linkages and demethylation took place in the structure of lignin to certain extent during modification with laccase, which contributed to the improvement of sulfonation reactivity. Under the condition of 0.3 MPa oxygen pressure, the ratio of s/g (guaiacyl/syringyl) increased after modification, which reduced the sulfonation reactivity of lignin. Simultaneously partial polymerization reaction, such as 4-O-5′, β-5, 5-5 and other reaction in the aromatic ring decreased the activity sites of C 2 , C 5 and C 6 . Abundant polymerization reaction of α-O increased steric hindrance of C 2 and C 6 in aromatic ring, resulting in low sulfonation reactivity of lignin. -- Highlights: ► The modification of alkali lignin with laccase was investigated. ► The sulfonation reactivity increased under the condition of atmosphere pressure. ► More content of guaiacyl and hydroxy, the less content of methoxyl, syringyl can enhance the sulfonation reactivity of lignin. ► Partial moieties polymerized each other with α-O linkgages during treatment with laccase under oxygen pressure. ► The steric hindrance on C 2 and C 6 in aromatic ring resulted in low sulfonation reaction reactivity of lignin

  8. Transport and Reactivity of Decontaminants to Provide Hazard Mitigation of Chemical Warfare Agents from Materials

    Science.gov (United States)

    2016-06-01

    2013 4. TITLE AND SUBTITLE Transport and Reactivity of Decontaminants to Provide Hazard Mitigation of Chemical Warfare Agents from Materials 5a...directions for future decontamination formulation approaches. 15. SUBJECT TERMS GD HD Decontamination Hazard mitigation VX Chemical warfare agent... DECONTAMINANTS TO PROVIDE HAZARD MITIGATION OF CHEMICAL WARFARE AGENTS FROM MATERIALS 1. INTRODUCTION Decontamination of materials is the

  9. Reactive hydro- end chlorocarbons in the troposphere and lower stratosphere : sources, distributions, and chemical impact

    NARCIS (Netherlands)

    Scheeren, H.A.

    2003-01-01

    The work presented in this thesis focuses on measurements of chemical reactive C2 C7 non-methane hydrocarbons (NMHC) and C1 C2 chlorocarbons with atmospheric lifetimes of a few hours up to about a year. The group of reactive chlorocarbons includes the most abundant atmospheric species with large

  10. Chemical reactivity of the compressed noble gas atoms and their ...

    Indian Academy of Sciences (India)

    Attempts are made to gain insights into the effect of confinement of noble gas atoms on their various reactivity indices. Systems become harder, less polarizable and difficult to excite as the compression increases. Ionization also causes similar effects. A quantum fluid density functional technique is adopted in order to study ...

  11. Chemical Characterization and Reactivity of Fuel-Oxidizer Reaction Product

    Science.gov (United States)

    David, Dennis D.; Dee, Louis A.; Beeson, Harold D.

    1997-01-01

    Fuel-oxidizer reaction product (FORP), the product of incomplete reaction of monomethylhydrazine and nitrogen tetroxide propellants prepared under laboratory conditions and from firings of Shuttle Reaction Control System thrusters, has been characterized by chemical and thermal analysis. The composition of FORP is variable but falls within a limited range of compositions that depend on three factors: the fuel-oxidizer ratio at the time of formation; whether the composition of the post-formation atmosphere is reducing or oxidizing; and the reaction or post-reaction temperature. A typical composition contains methylhydrazinium nitrate, ammonium nitrate, methylammonium nitrate, and trace amounts of hydrazinium nitrate and 1,1-dimethylhydrazinium nitrate. Thermal decomposition reactions of the FORP compositions used in this study were unremarkable. Neither the various compositions of FORP, the pure major components of FORP, nor mixtures of FORP with propellant system corrosion products showed any unusual thermal activity when decomposed under laboratory conditions. Off-limit thruster operations were simulated by rapid mixing of liquid monomethylhydrazine and liquid nitrogen tetroxide in a confined space. These tests demonstrated that monomethylhydrazine, methylhydrazinium nitrate, ammonium nitrate, or Inconel corrosion products can induce a mixture of monomethylhydrazine and nitrogen tetroxide to produce component-damaging energies. Damaging events required FORP or metal salts to be present at the initial mixing of monomethylhydrazine and nitrogen tetroxide.

  12. Testing and comparison of seventeen decontamination chemicals

    International Nuclear Information System (INIS)

    Demmer, R.L.

    1996-09-01

    This report details the testing and evaluation of seventeen decontamination chemicals. Tests were conducted with SIMCON (simulated contamination) coupons under controlled conditions to compare cleaning effectiveness, overall corrosion potential for plant equipment, interim waste generation and final waste generation

  13. Modification of chemical reactivity of enzymatic hydrolysis lignin by ultrasound treatment in dilute alkaline solutions.

    Science.gov (United States)

    Ma, Zhuoming; Li, Shujun; Fang, Guizhen; Patil, Nikhil; Yan, Ning

    2016-12-01

    In this study, we have explored various ultrasound treatment conditions for structural modification of enzymatic hydrolysis lignin (EHL) for enhanced chemical reactivity. The key structural modifications were characterized by using a combination of analytical methods, including, Fourier Transform-Infrared spectroscopy (FTIR), Proton Nuclear Magnetic Resonance ( 1 H NMR), Gel permeation chromatography (GPC), X-ray photoelectron spectroscopy (XPS), and Folin-Ciocalteu (F-C) method. Chemical reactivity of the modified EHL samples was determined by both 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging activity and their reactivity towards formaldehyde. It was observed that the modified EHL had a higher phenolic hydroxyl group content, a lower molecular weight, a higher reactivity towards formaldehyde, and a greater antioxidant property. The higher reactivity demonstrated by the samples after treatment suggesting that ultrasound is a promising method for modifying enzymatic hydrolysis lignin for value-added applications. Copyright © 2016 Elsevier B.V. All rights reserved.

  14. Models for risk assessment of reactive chemicals in aquatic toxicology

    NARCIS (Netherlands)

    Freidig, Andreas Peter

    2000-01-01

    A quantitative structure property relationship (QSPR) for a,b-unsaturated carboxylates (mainly acrylates and methacrylates) was established in chapter 2. Chemical reaction rate constants were measured for 12 different chemicals with three different nucleophiles, namely H 2 O, OH - and glutathione

  15. Reactive skin decontamination lotion (RSDL) for the decontamination of chemical warfare agent (CWA) dermal exposure.

    Science.gov (United States)

    Schwartz, M D; Hurst, C G; Kirk, M A; Reedy, S J D; Braue, E H

    2012-08-01

    Rapid decontamination of the skin is the single most important action to prevent dermal absorption of chemical contaminants in persons exposed to chemical warfare agents (CWA) and toxic industrial chemicals (TICs) as a result of accidental or intentional release. Chemicals on the skin may be removed by mechanical means through the use of dry sorbents or water. Recent interest in decontamination systems which both partition contaminants away from the skin and actively neutralize the chemical has led to the development of several reactive decontamination solutions. This article will review the recently FDA-approved Reactive Skin Decontamination Lotion (RSDL) and will summarize the toxicity and efficacy studies conducted to date. Evidence of RSDL's superior performance against vesicant and organophosphorus chemical warfare agents compared to water, bleach, and dry sorbents, suggests that RSDL may have a role in mass human exposure chemical decontamination in both the military and civilian arenas.

  16. Fast Flux Test Facility (FFTF) feedback reactivity components

    International Nuclear Information System (INIS)

    Nguyen, D.H.

    1988-04-01

    The static tests conducted during Cycle 8A (1986) of the FFTF have allowed, for the first time, the experimental determination of each of the feedback reactivities caused by the following mechanisms: fuel axial expansion, control rod repositioning, core radial expansion, and subassembly bowing. A semiempirical equation was obtained to describe each of these feedback components that depended only on the relevant reactor temperature (bowing was presented in a tabular form). The Doppler and sodium density reactivities were calculated using existing mechanistic methods. Although they could also be fitted with closed-form equations depending only on temperatures, these equations are not needed in transient analyses using whole core safety computer codes, which use mechanistic methods. The static feedback reactivity model was extended to obtain a dynamic model via the concept of ''time constants.'' Besides being used for transient analyses in the FFTF, these feedback equations constitute a database for the validation and/or calibration of mechanistic feedback reactivity models. 2 refs., 6 tabs

  17. A Conceptual Framework for Predicting the Toxicity of Reactive Chemicals: Modeling Soft Electrophilicity

    Science.gov (United States)

    Although the literature is replete with QSAR models developed for many toxic effects caused by reversible chemical interactions, the development of QSARs for the toxic effects of reactive chemicals lacks a consistent approach. While limitations exit, an appropriate starting-point...

  18. Communication: Enhanced chemical reactivity of graphene on a Ni(111) substrate

    Energy Technology Data Exchange (ETDEWEB)

    Ambrosetti, Alberto; Silvestrelli, Pier Luigi [Dipartimento di Fisica e Astronomia, Università di Padova, via Marzolo 8, I–35131 Padova, Italy and DEMOCRITOS National Simulation Center of the Italian Istituto Officina dei Materiali (IOM) of the Italian National Research Council (CNR), Trieste (Italy)

    2016-03-21

    Due to the unique combination of structural, mechanical, and transport properties, graphene has emerged as an exceptional candidate for catalysis applications. The low chemical reactivity caused by sp{sup 2} hybridization and strongly delocalized π electrons, however, represents a main challenge for straightforward use of graphene in its pristine, free-standing form. Following recent experimental indications, we show that due to charge hybridization, a Ni(111) substrate can enhance the chemical reactivity of graphene, as exemplified by the interaction with the CO molecule. While CO only physisorbs on free-standing graphene, chemisorption of CO involving formation of ethylene dione complexes is predicted in Ni(111)-graphene. Higher chemical reactivity is also suggested in the case of oxidized graphene, opening the way to a simple and efficient control of graphene chemical properties, devoid of complex defect patterning or active metallic structures deposition.

  19. Communication: Enhanced chemical reactivity of graphene on a Ni(111) substrate

    International Nuclear Information System (INIS)

    Ambrosetti, Alberto; Silvestrelli, Pier Luigi

    2016-01-01

    Due to the unique combination of structural, mechanical, and transport properties, graphene has emerged as an exceptional candidate for catalysis applications. The low chemical reactivity caused by sp 2 hybridization and strongly delocalized π electrons, however, represents a main challenge for straightforward use of graphene in its pristine, free-standing form. Following recent experimental indications, we show that due to charge hybridization, a Ni(111) substrate can enhance the chemical reactivity of graphene, as exemplified by the interaction with the CO molecule. While CO only physisorbs on free-standing graphene, chemisorption of CO involving formation of ethylene dione complexes is predicted in Ni(111)-graphene. Higher chemical reactivity is also suggested in the case of oxidized graphene, opening the way to a simple and efficient control of graphene chemical properties, devoid of complex defect patterning or active metallic structures deposition.

  20. Phase rule calculations and the thermodynamics of reactive systems under chemical equilibrium

    Directory of Open Access Journals (Sweden)

    PLATT G. M.

    1999-01-01

    Full Text Available In this paper, we examine the resolution of some phase rule problems within the context of multiple chemical equilibrium reactions, using cubic equations of state and an activity coefficient model. Bubble and dew reactive surfaces, reactive azeotropic loci and reactive critical loci are generated and presented in graphical form. Also isobaric bubble and dew reactive enthalpy loci, which may be useful in the modeling of reactive distillation operations, are depicted. All the formalism here employed is developed within the coordinate transformation of Ung and Doherty, which is appropriate for equilibrium reactive or multireactive systems. The major contribution of this work is the determination of critical loci for reactive or multireactive equilibrium systems. Since it is known that for some class of chemical reactions the kinetics and product distribution exhibit high sensitivity to pressure near criticality, the present study may be useful as a predicting tool in these cases if the chemical equilibrium condition is not too far from the real phenomenon.

  1. Adsorption of a reactive dye on chemically modified activated carbons--influence of pH.

    Science.gov (United States)

    Orfão, J J M; Silva, A I M; Pereira, J C V; Barata, S A; Fonseca, I M; Faria, P C C; Pereira, M F R

    2006-04-15

    The surface chemistry of a commercial activated carbon with a slightly basic nature was modified by appropriate treatments in order to obtain two additional samples, respectively with acidic and basic properties, without changing its textural parameters significantly. Different techniques (N2 adsorption at 77 K, temperature programmed desorption, and determination of acidity, basicity, and pH at the point of zero charge) were used to characterize the adsorbents. Kinetic and equilibrium adsorption data of a selected textile reactive dye (Rifafix Red 3BN, C.I. reactive red 241) on the mentioned materials were obtained at the pH values of 2, 7, and 12. The kinetic curves are fitted using the second-order model. The respective rate constants seem to diminish progressively with the initial concentration for the more diluted solutions tested, reaching a constant value at higher concentrations, which depends on the experimental system under consideration (adsorbent and pH). In general, the Langmuir model provides the best fit for the equilibrium data. The different uptakes obtained are discussed in relation to the surface chemical properties of the adsorbents. It is shown that the adsorption of the reactive (anionic) dye on the basic sample (prepared by thermal treatment under H2 flow at 700 degrees C) is favored. This conclusion is explained on the basis of the dispersive and electrostatic interactions involved. Moreover, it is also shown that the optimal adsorption condition for all the activated carbons tested corresponds to solution pH values not higher than the pH(pzc) of the adsorbents, which may be interpreted by taking into account the electrostatic forces present.

  2. Reactive Ion Etching as Cleaning Method Post Chemical Mechanical Polishing for Phase Change Memory Device

    International Nuclear Information System (INIS)

    Min, Zhong; Zhi-Tang, Song; Bo, Liu; Song-Lin, Feng; Bomy, Chen

    2008-01-01

    In order to improve nano-scale phase change memory performance, a super-clean interface should be obtained after chemical mechanical polishing (CMP) of Ge 2 Sb 2 Te 5 phase change films. We use reactive ion etching (RIE) as the cleaning method. The cleaning effect is analysed by scanning electron microscopy and an energy dispersive spectrometer. The results show that particle residue on the surface has been removed. Meanwhile, Ge 2 Sb 2 Te 5 material stoichiometric content ratios are unchanged. After the top electrode is deposited, current-voltage characteristics test demonstrates that the set threshold voltage is reduced from 13 V to 2.7V and the threshold current from 0.1mA to 0.025mA. Furthermore, we analyse the RIE cleaning principle and compare it with the ultrasonic method

  3. Evaluation of the chemical reactivity in lignin precursors using the Fukui function.

    Science.gov (United States)

    Martinez, Carmen; Rivera, José L; Herrera, Rafael; Rico, José L; Flores, Nelly; Rutiaga, José G; López, Pablo

    2008-02-01

    The hydroxycinnamyl alcohols: p-coumarol, coniferol and sinapol are considered the basic units and precursors of lignins models. In this work, the specific reactivity of these molecules was studied. We investigate their intrinsic chemical reactivity in terms of the Fukui function, applying the principle of hard and soft acids and bases (HSAB) in the framework of the density functional theory (DFT). Comparisons of their nucleophilic, electrophilic and free radical reactivity show their most probably sites to form linkages among them. It is found that the most reactive sites, for reactions involving free radicals, are the carbons at the beta-position in the p-coumarol and sinapol molecules, whilst the regions around the carbon-oxygen bond of the phenoxyl group are the most reactive in coniferol.

  4. Reactive formulations for a neutralization of toxic industrial chemicals

    Science.gov (United States)

    Tucker, Mark D [Albuqueruqe, NM; Betty, Rita G [Rio Rancho, NM

    2006-10-24

    Decontamination formulations for neutralization of toxic industrial chemicals, and methods of making and using same. The formulations are effective for neutralizing malathion, hydrogen cyanide, sodium cyanide, butyl isocyanate, carbon disulfide, phosgene gas, capsaicin in commercial pepper spray, chlorine gas, anhydrous ammonia gas; and may be effective at neutralizing hydrogen sulfide, sulfur dioxide, formaldehyde, ethylene oxide, methyl bromide, boron trichloride, fluorine, tetraethyl pyrophosphate, phosphorous trichloride, arsine, and tungsten hexafluoride.

  5. Chemical and Photochemical Reactivity in Microemulsions and Waterless Microemulsions.

    Science.gov (United States)

    1988-02-10

    virtually the same as that found in the alcohol rich microemulsion A. This value is also close to that found in pure butanol (= 5.0 - table I). It would...formamide or alcohol rich). RESEARCH PATTERN -Supplementing the physical chemical study of the microemulsion medium involving ionic surfactants with density...SAMII (1/02/1988) Ii&N 3 Part II - OXYDATIONS BY HYDROPEROXIDES IN MICROEMULSIONS E. OLIVEROS and M.T. MAURETTE During the past six months, the financial

  6. Importance of asparagine on the conformational stability and chemical reactivity of selected anti-inflammatory peptides

    Energy Technology Data Exchange (ETDEWEB)

    Soriano-Correa, Catalina, E-mail: csorico@comunidad.unam.mx [Química Computacional, Facultad de Estudios Superiores (FES)-Zaragoza, Universidad Nacional Autónoma de México (UNAM), Iztapalapa, C.P. 09230 México, D.F. (Mexico); Barrientos-Salcedo, Carolina [Laboratorio de Química Médica y Quimiogenómica, Facultad de Bioanálisis Campus Veracruz-Boca del Río, Universidad Veracruzana, C.P. 91700 Veracruz (Mexico); Campos-Fernández, Linda; Alvarado-Salazar, Andres [Química Computacional, Facultad de Estudios Superiores (FES)-Zaragoza, Universidad Nacional Autónoma de México (UNAM), Iztapalapa, C.P. 09230 México, D.F. (Mexico); Esquivel, Rodolfo O. [Departamento de Química, Universidad Autónoma Metropolitana-Iztapalapa (UAM-Iztapalapa), C.P. 09340 México, D.F. (Mexico)

    2015-08-18

    Highlights: • Asparagine plays an important role to anti-inflammatory effect of peptides. • The electron-donor substituent groups favor the formation of the hydrogen bonds, which contribute in the structural stability of peptides. • Chemical reactivity and the physicochemical features are crucial in the biological functions of peptides. - Abstract: Inflammatory response events are initiated by a complex series of molecular reactions that generate chemical intermediaries. The structure and properties of peptides and proteins are determined by the charge distribution of their side chains, which play an essential role in its electronic structure and physicochemical properties, hence on its biological functionality. The aim of this study was to analyze the effect of changing one central amino acid, such as substituting asparagine for aspartic acid, from Cys–Asn–Ser in aqueous solution, by assessing the conformational stability, physicochemical properties, chemical reactivity and their relationship with anti-inflammatory activity; employing quantum-chemical descriptors at the M06-2X/6-311+G(d,p) level. Our results suggest that asparagine plays a more critical role than aspartic acid in the structural stability, physicochemical features, and chemical reactivity of these tripeptides. Substituent groups in the side chain cause significant changes on the conformational stability and chemical reactivity, and consequently on their anti-inflammatory activity.

  7. Large-Eddy Simulation of Chemically Reactive Pollutant Transport from a Point Source in Urban Area

    Science.gov (United States)

    Du, Tangzheng; Liu, Chun-Ho

    2013-04-01

    Most air pollutants are chemically reactive so using inert scalar as the tracer in pollutant dispersion modelling would often overlook their impact on urban inhabitants. In this study, large-eddy simulation (LES) is used to examine the plume dispersion of chemically reactive pollutants in a hypothetical atmospheric boundary layer (ABL) in neutral stratification. The irreversible chemistry mechanism of ozone (O3) titration is integrated into the LES model. Nitric oxide (NO) is emitted from an elevated point source in a rectangular spatial domain doped with O3. The LES results are compared well with the wind tunnel results available in literature. Afterwards, the LES model is applied to idealized two-dimensional (2D) street canyons of unity aspect ratio to study the behaviours of chemically reactive plume over idealized urban roughness. The relation among various time scales of reaction/turbulence and dimensionless number are analysed.

  8. Effect of mechanical activation on structure changes and reactivity in further chemical modification of lignin.

    Science.gov (United States)

    Zhao, Xiaohong; Zhang, Yanjuan; Hu, Huayu; Huang, Zuqiang; Yang, Mei; Chen, Dong; Huang, Kai; Huang, Aimin; Qin, Xingzhen; Feng, Zhenfei

    2016-10-01

    Lignin was treated by mechanical activation (MA) in a customized stirring ball mill, and the structure and reactivity in further esterification were studied. The chemical structure and morphology of MA-treated lignin and the esterified products were analyzed by chemical analysis combined with UV/vis spectrometer, FTIR,NMR, SEM and particle size analyzer. The results showed that MA contributed to the increase of aliphatic hydroxyl, phenolic hydroxyl, carbonyl and carboxyl groups but the decrease of methoxyl groups. Moreover, MA led to the decrease of particle size and the increase of specific surface area and roughness of surface in lignin. The reactivity of lignin was enhanced significantly for the increase of hydroxyl content and the improvement of mass transfer in chemical reaction caused by the changes of molecular structure and morphological structure. The process of MA is green and simple, and is an effective method for enhancing the reactivity of lignin. Copyright © 2016 Elsevier B.V. All rights reserved.

  9. Testing and evaluation of eight decontamination chemicals

    International Nuclear Information System (INIS)

    Demmer, R.

    1994-09-01

    This report covers experimental work comparing eight different decontamination chemicals. Seven of these chemicals have some novelty, or are not currently in use at the ICPP. The eighth is a common ICPP decontamination reagent used as a baseline for effective comparison. Decontamination factors, waste generation values, and corrosion rates are tabulated for these chemicals. Recommendations are given for effective methods of non-sodium or low-sodium decontamination chemicals. The two most effective chemical for decontamination found in these test were a dilute hydrofluoric and nitric acid (HF/HNO 3 ) mixture and a fluoroboric acid solution. The fluoroboric acid solution (1 molar) was by far the most effective decontamination reagent, but suffered the problem of generating significant final calcine volume. The HF/HNO 3 solution performed a very good decontamination of the SIMCON coupons while generating only small amounts of calcine volume. Concentration variables were also tested, and optimized for these two solutions. Several oxidation/reduction decon chemical systems were also tested. These systems were similar to the TURCO 4502 and TURCO 4521 solutions used for general decontamination at the ICPP. A low sodium alternative, nitric acid/potassium permanganate, to the ''high sodium'' TURCO 4502 was tested extensively, optimized and recommended for general ICPP use. A reductive chemical solution, oxalic acid/nitric acid was also shown to have significant advantages

  10. Unconfirmed reactive screening tests and their impact on donor management

    International Nuclear Information System (INIS)

    Rahman, M.; Khan, S.A.

    2008-01-01

    To determine the percentage of false positive testing for transfusion transmitted infections (TTIs) using immunochromatographic test (ICT) as first line of screening tests and its effect on loss of volunteer blood donors. Over a period of three months, samples from blood bags of donors undergoing phlebotomy at teaching hospital blood banks in Lahore were screened for human immunodeficiency virus (HIV), hepatitis B (HBV) and hepatitis C (HCV) by immunochromatographic tests. Those found positive on initial screening were re-tested by ELISA method at the screening laboratory of the Institute of Haematology and Blood Transfusion Service, Punjab. Lahore. Out of a total of 62090 voluntary blood donors, 469 donors were found to be initially reactive for either HIV, HBV or HCV. Amongst these 96 (0.15%) blood donors were found to have tested falsely positive for HIV, HBV or HCV as compared to testing by ELISA. False positive testing rate of 0.15% or 96 out of a total of 62090 donors is rather small in terms of loss of voluntary donors and appropriate utilization of available resources. Although immunochromatographic testing is not the gold standard, however it serves an important purpose of initial donor screening. (author)

  11. New chemical-DSMC method in numerical simulation of axisymmetric rarefied reactive flow

    Science.gov (United States)

    Zakeri, Ramin; Kamali Moghadam, Ramin; Mani, Mahmoud

    2017-04-01

    The modified quantum kinetic (MQK) chemical reaction model introduced by Zakeri et al. is developed for applicable cases in axisymmetric reactive rarefied gas flows using the direct simulation Monte Carlo (DSMC) method. Although, the MQK chemical model uses some modifications in the quantum kinetic (QK) method, it also employs the general soft sphere collision model and Stockmayer potential function to properly select the collision pairs in the DSMC algorithm and capture both the attraction and repulsion intermolecular forces in rarefied gas flows. For assessment of the presented model in the simulation of more complex and applicable reacting flows, first, the air dissociation is studied in a single cell for equilibrium and non-equilibrium conditions. The MQK results agree well with the analytical and experimental data and they accurately predict the characteristics of the rarefied flowfield with chemical reaction. To investigate accuracy of the MQK chemical model in the simulation of the axisymmetric flow, air dissociation is also assessed in an axial hypersonic flow around two geometries, the sphere as a benchmark case and the blunt body (STS-2) as an applicable test case. The computed results including the transient, rotational and vibrational temperatures, species concentration in the stagnation line, and also the heat flux and pressure coefficient on the surface are compared with those of the other chemical methods like the QK and total collision energy (TCE) models and available analytical and experimental data. Generally, the MQK chemical model properly simulates the chemical reactions and predicts flowfield characteristics more accurate rather than the typical QK model. Although in some cases, results of the MQK approaches match with those of the TCE method, the main point is that the MQK does not need any experimental data or unrealistic assumption of specular boundary condition as used in the TCE method. Another advantage of the MQK model is the

  12. Skin test reactivity among Danish children measured 15 years apart

    DEFF Research Database (Denmark)

    Thomsen, SF; Ulrik, Charlotte Suppli; Porsbjerg, C

    2006-01-01

    BACKGROUND: Knowledge of secular trends in the prevalence of allergy among children stems in large part from questionnaire surveys, whereas repeated cross-sectional studies using objective markers of atopic sensitization are sparse. OBJECTIVES: To investigate whether the prevalence of skin prick...... (n = 527) and the second in 2001 (n = 480). Skin test reactivity to nine common aeroallergens was measured at both occasions. RESULTS: The prevalence of positive SPT to at least one allergen decreased from 24.1% in 1986 to 18.9% in 2001, (p = 0.05). We found a declining prevalence of sensitization...

  13. Reactivity control system of the high temperature engineering test reactor

    International Nuclear Information System (INIS)

    Tachibana, Yukio; Sawahata, Hiroaki; Iyoku, Tatsuo; Nakazawa, Toshio

    2004-01-01

    The reactivity control system of the high temperature engineering test reactor (HTTR) consists of a control rod system and a reserve shutdown system. During normal operation, reactivity is controlled by the control rod system, which consists of 32 control rods (16 pairs) and 16 control rod drive mechanisms except for the case when the center control rods are removed to perform an irradiation test. In an unlikely event that the control rods fail to be inserted, reserve shutdown system is provided to insert pellets of neutron-absorbing material into the core. Alloy 800H is chosen for the metallic parts of the control rods. Because the maximum temperature of the control rods reaches about 900 deg. C at reactor scrams, structural design guideline and design material data on Alloy 800H are needed for the high temperature design. The design guideline for the HTTR control rod is based on ASME Code Case N-47-21. Design material data is also determined and shown in this paper. Observing the guideline, temperature and stress analysis were conducted; it can be confirmed that the target life of the control rods of 5 years can be achieved. Various tests conducted for the control rod system and the reserve shutdown system are also described

  14. Modeling turbulence structure. Chemical kinetics interaction in turbulent reactive flows

    Energy Technology Data Exchange (ETDEWEB)

    Magnussen, B F [The Norwegian Univ. of Science and Technology, Trondheim (Norway)

    1998-12-31

    The challenge of the mathematical modelling is to transfer basic physical knowledge into a mathematical formulation such that this knowledge can be utilized in computational simulation of practical problems. The combustion phenomena can be subdivided into a large set of interconnected phenomena like flow, turbulence, thermodynamics, chemical kinetics, radiation, extinction, ignition etc. Combustion in one application differs from combustion in another area by the relative importance of the various phenomena. The difference in fuel, geometry and operational conditions often causes the differences. The computer offers the opportunity to treat the individual phenomena and their interactions by models with wide operational domains. The relative magnitude of the various phenomena therefore becomes the consequence of operational conditions and geometry and need not to be specified on the basis of experience for the given problem. In mathematical modelling of turbulent combustion, one of the big challenges is how to treat the interaction between the chemical reactions and the fluid flow i.e. the turbulence. Different scientists adhere to different concepts like the laminar flamelet approach, the pdf approach of the Eddy Dissipation Concept. Each of these approaches offers different opportunities and problems. All these models are based on a sound physical basis, however none of these have general validity in taking into consideration all detail of the physical chemical interaction. The merits of the models can only be judged by their ability to reproduce physical reality and consequences of operational and geometric conditions in a combustion system. The presentation demonstrates and discusses the development of a coherent combustion technology for energy conversion and safety based on the Eddy Dissipation Concept by Magnussen. (author) 30 refs.

  15. Modeling turbulence structure. Chemical kinetics interaction in turbulent reactive flows

    Energy Technology Data Exchange (ETDEWEB)

    Magnussen, B.F. [The Norwegian Univ. of Science and Technology, Trondheim (Norway)

    1997-12-31

    The challenge of the mathematical modelling is to transfer basic physical knowledge into a mathematical formulation such that this knowledge can be utilized in computational simulation of practical problems. The combustion phenomena can be subdivided into a large set of interconnected phenomena like flow, turbulence, thermodynamics, chemical kinetics, radiation, extinction, ignition etc. Combustion in one application differs from combustion in another area by the relative importance of the various phenomena. The difference in fuel, geometry and operational conditions often causes the differences. The computer offers the opportunity to treat the individual phenomena and their interactions by models with wide operational domains. The relative magnitude of the various phenomena therefore becomes the consequence of operational conditions and geometry and need not to be specified on the basis of experience for the given problem. In mathematical modelling of turbulent combustion, one of the big challenges is how to treat the interaction between the chemical reactions and the fluid flow i.e. the turbulence. Different scientists adhere to different concepts like the laminar flamelet approach, the pdf approach of the Eddy Dissipation Concept. Each of these approaches offers different opportunities and problems. All these models are based on a sound physical basis, however none of these have general validity in taking into consideration all detail of the physical chemical interaction. The merits of the models can only be judged by their ability to reproduce physical reality and consequences of operational and geometric conditions in a combustion system. The presentation demonstrates and discusses the development of a coherent combustion technology for energy conversion and safety based on the Eddy Dissipation Concept by Magnussen. (author) 30 refs.

  16. Chemical stability and in chemico reactivity of 24 fragrance ingredients of concern for skin sensitization risk assessment.

    Science.gov (United States)

    Avonto, Cristina; Wang, Mei; Chittiboyina, Amar G; Vukmanovic, Stanislav; Khan, Ikhlas A

    2018-02-01

    Twenty-four pure fragrance ingredients have been identified as potential concern for skin sensitization. Several of these compounds are chemically unstable and convert into reactive species upon exposure to air or light. In the present work, a systematic investigation of the correlation between chemical stability and reactivity has been undertaken. The compounds were subjected to forced photodegradation for three months and the chemical changes were studied with GC-MS. At the end of the stability study, two-thirds of the samples were found to be unstable. The generation of chemically reactive species was investigated using the in chemico HTS-DCYA assay. Eleven and fourteen compounds were chemically reactive before and after three months, respectively. A significant increase in reactivity upon degradation was found for isoeugenol, linalool, limonene, lyral, citronellol and geraniol; in the same conditions, the reactivity of hydroxycitronellal decreased. The non-reactive compounds α-isomethyl ionone, benzyl alcohol, amyl cinnamal and farnesol became reactive after photo-oxidative degradation. Overall, forced degradation resulted in four non-reactive fragrance compounds to display in chemico thiol reactivity, while ten out of 24 compounds remained inactive. Chemical degradation does not necessarily occur with generation of reactive species. Non-chemical activation may be involved for the 10 stable unreactive compounds. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. Methyl salicylate: a reactive chemical warfare agent surrogate to detect reaction with hypochlorite.

    Science.gov (United States)

    Salter, W Bruce; Owens, Jeffery R; Wander, Joseph D

    2011-11-01

    Methyl salicylate (MeS) has a rich history as an inert physical simulant for the chemical warfare agents sulfur mustard and soman, where it is used extensively for liquid- and vapor-permeation testing. Here we demonstrate possible utility of MeS as a reactivity simulant for chlorine-based decontaminants. In these experiments MeS was reacted with sodium hypochlorite varying stoichiometry, temperature, reaction time, and pH. No colored oxidation products were observed; however, chlorination of the aromatic ring occurred ortho (methyl 3-chlorosalicylate) and para (methyl 5-chlorosalicylate) to the position bearing the -OH group in both the mono- and disubstituted forms. The monosubstituted para product accumulated initially, and the ortho and 3,5-dichloro products formed over the next several hours. Yields from reactions conducted below pH 11 declined rapidly with decreasing pH. Reactions run at 40 °C produced predominantly para substitution, while those run at 0 °C produced lower yields of ortho- and para-substituted products. Reactions were also carried out on textile substrates of cotton, 50/50 nylon-cotton, and a meta aramid. The textile data broadly reproduced reaction times and stoichiometry observed in the liquid phase, but are complicated by physical and possibly chemical interactions with the fabric. These data indicate that, for hypochlorite-containing neutralizing agents operating at strongly alkaline pH, one can expect MeS to react stoichiometrically with the hypochlorite it encounters. This suggests utility of MeS in lieu of such highly hazardous surrogates as monochloroalkyl sulfides as a simulant for threat scenarios involving the stoichiometric decomposition of sulfur mustard. Specifically, the extent of coverage of the simulant on a fabric by the neutralizing agent can be directly measured. Similar reactivity toward other halogen oxidizing agents is likely but remains to be demonstrated.

  18. Applicability of modified burst test data to reactivity initiated accident

    Energy Technology Data Exchange (ETDEWEB)

    Yueh, K., E-mail: yuehky@hotmail.com

    2017-05-15

    A comprehensive irradiated cladding mechanical property dataset was generated by a recently developed modified burst test (MBT) under reactivity initiated accident (RIA) loading conditions [1,2]. The test data contains a wide range of test conditions that could bridge the gap between fast transient test reactor data (short pulse and/or low temperature) and prototypical commercial reactor conditions. This paper documents an evaluation performed to demonstrate the applicability of the MBT data to fuel cladding performance under RIA conditions. The current effort includes a comparison of calculated fuel cladding failure/burst strain for tests conducted at the Japan Atomic Energy Agency's (JAEA) Nuclear Safety Research Reactor (NSRR) to the MBT dataset, and an evaluation of potential mechanisms on how some NSRR tests survived beyond the cladding loading capacity. A simple shell model, coupled with temperature output from the Falcon fuel performance code, was used to calculate the fuel pellet thermal expansion of NSRR tests at the point of failure. The calculated fuel pellet thermal expansion correlates well directly with the MBT data at similar loading conditions. A 3-dimensional (3D) finite element analysis (FEA) model was used to evaluate fuel movement potential during a RIA. The evaluation indicates fuel relocation into the pellet chamfer and later into the dish is possible once a temperature threshold is reached before cladding failure and thus could significantly increase the fuel rod energy absorption capacity in a RIA event.

  19. Chemical and physical characteristics of phosphate rock materials of varying reactivity

    International Nuclear Information System (INIS)

    Syers, J.K.; Currie, L.D.

    1986-01-01

    Several chemical and physical properties of 10 phosphate rock (PR) materials of varying reactivity were evaluated. The highest concentrations of As and Cd were noted. Because Cd and U can accumulate in biological systems, it may be necessary to direct more attention towards the likely implications of Cd and U concentrations when evaluating a PR for direct application. Three sequential extractions with 2% citric acid may be more useful for comparing the chemical solubility of PR materials, particularly for those containing appreciable CaC0 3 . The poor relationship obtained between surface area and the solubility of the PR materials suggests that surface area plays a secondary role to chemical reactivity in controlling the solubility of a PR in a chemical extractant. A Promesh plot provided an effective method for describing the particle-size characteristics of those PR materials which occurred as sands. Fundamental characteristics, such as mean particle size and uniformity, can readily be determined from a Promesh plot. (author)

  20. Coal structure and reactivity changes induced by chemical demineralisation

    Energy Technology Data Exchange (ETDEWEB)

    Rubiera, F.; Arenillas, A.; Pevida, C.; Garcia, R.; Pis, J.J. [Department of Energy and Environment, Instituto Nacional del Carbon, CSIC, Apartado 73, 33080 Oviedo (Spain); Steel, K.M.; Patrick, J.W. [Fuel Technology Group, School of Chemical, Environmental and Mining Engineering, Nottingham University, University Park, NG7 2RD Nottingham (United Kingdom)

    2002-12-01

    The aim of this work was to determine the influence that an advanced demineralisation procedure has on the combustion characteristics of coal. A high-volatile bituminous coal with 6.2% ash content was treated in a mixture of hydrofluoric and fluorosilicic acids (HF/H{sub 2}SiF{sub 6}). Nitric acid was used either as a pretreatment, or as a washing stage after HF/H{sub 2}SiF{sub 6} demineralisation, with an ash content as low as 0.3% being attained in the latter case. The structural changes produced by the chemical treatment were evaluated by comparison of the FTIR spectra of the raw and treated coal samples. The devolatilisation and combustibility behaviour of the samples was studied by using a thermobalance coupled to a mass spectrometer (TGA-MS) for evolved gas analysis. The combustibility characteristics of the cleaned samples were clearly improved, there being a decrease in SO{sub 2} emissions.

  1. Efficient and Safe Chemical Gas Generators with Nanocomposite Reactive Materials

    Science.gov (United States)

    2015-11-30

    thermolysis and hydrolysis . This reaction also releases hydrogen from water, thus increasing the total hydrogen yield. The investigation of iodine...for AB thermolysis and hydrolysis . This reaction also releases hydrogen from water, thus increasing the total hydrogen yield. Experiments have... hydrogen yield. The isotopic tests have shown that AB participates in two parallel processes − thermolysis and hydrolysis . Because of this, as much as 88

  2. Chemical Reactive Anchoring Lipids with Different Performance for Cell Surface Re-engineering Application.

    Science.gov (United States)

    Vabbilisetty, Pratima; Boron, Mallorie; Nie, Huan; Ozhegov, Evgeny; Sun, Xue-Long

    2018-02-28

    Introduction of selectively chemical reactive groups at the cell surface enables site-specific cell surface labeling and modification opportunity, thus facilitating the capability to study the cell surface molecular structure and function and the molecular mechanism it underlies. Further, it offers the opportunity to change or improve a cell's functionality for interest of choice. In this study, two chemical reactive anchor lipids, phosphatidylethanolamine-poly(ethylene glycol)-dibenzocyclooctyne (DSPE-PEG 2000 -DBCO) and cholesterol-PEG-dibenzocyclooctyne (CHOL-PEG 2000 -DBCO) were synthesized and their potential application for cell surface re-engineering via lipid fusion were assessed with RAW 264.7 cells as a model cell. Briefly, RAW 264.7 cells were incubated with anchor lipids under various concentrations and at different incubation times. The successful incorporation of the chemical reactive anchor lipids was confirmed by biotinylation via copper-free click chemistry, followed by streptavidin-fluorescein isothiocyanate binding. In comparison, the cholesterol-based anchor lipid afforded a higher cell membrane incorporation efficiency with less internalization than the phospholipid-based anchor lipid. Low cytotoxicity of both anchor lipids upon incorporation into the RAW 264.7 cells was observed. Further, the cell membrane residence time of the cholesterol-based anchor lipid was evaluated with confocal microscopy. This study suggests the potential cell surface re-engineering applications of the chemical reactive anchor lipids.

  3. Deposition of chemically reactive and repellent sites on biosensor chips for reduced non-specific binding.

    Science.gov (United States)

    Gandhiraman, R P; Gubala, V; Le, N C H; Nam, Le Cao Hoai; Volcke, C; Doyle, C; James, B; Daniels, S; Williams, D E

    2010-08-01

    The performances of new polymeric materials with excellent optical properties and good machinability have led the biomedical diagnostics industry to develop cheap disposable biosensor platforms appropriate for point of care applications. Zeonor, a type of cycloolefin polymer (COP), is one such polymer that presents an excellent platform for biosensor chips. These polymer substrates have to be modified to have suitable physico-chemical properties for immobilizing proteins. In this work, we have demonstrated the amine functionalization of COP substrates, by plasma enhanced chemical vapour deposition (PECVD), through codeposition of ethylene diamine and 3-aminopropyltriethoxysilane precursors, for building chemistries on the plastic chip. The elemental composition, adhesion, ageing and reactivity of the plasma polymerized film were examined. The Si-O functionality present in amino silane contributed for a good interfacial adhesion of the coating to COP substrates and also acted as a network building layer for plasma polymerization. Wet chemical modification was then carried out on the amine functionalized chips to create chemically reactive isothiocyanate sites and protein repellent fluorinated sites on the same chip. The density of the reactive and repellent sites was altered by choosing appropriate mixtures of homofunctional phenyldiisothiocyanate (PDITC), pentafluoroisothiocyanate (5FITC) and phenylisothiocyanate (PITC) compounds. By tailoring the density of reactive binding sites and protein repellent sites, the non-specific binding of ssDNA has been decreased to a significant extent. Copyright 2010 Elsevier B.V. All rights reserved.

  4. Unifying principles of irreversibility minimization for efficiency maximization in steady-flow chemically-reactive engines

    International Nuclear Information System (INIS)

    Ramakrishnan, Sankaran; Edwards, Christopher F.

    2014-01-01

    Systems research has led to the conception and development of various steady-flow, chemically-reactive, engine cycles for stationary power generation and propulsion. However, the question that remains unanswered is: What is the maximum-efficiency steady-flow chemically-reactive engine architecture permitted by physics? On the one hand the search for higher-efficiency cycles continues, often involving newer processes and devices (fuel cells, carbon separation, etc.); on the other hand the design parameters for existing cycles are continually optimized in response to improvements in device engineering. In this paper we establish that any variation in engine architecture—parametric change or process-sequence change—contributes to an efficiency increase via one of only two possible ways to minimize total irreversibility. These two principles help us unify our understanding from a large number of parametric analyses and cycle-optimization studies for any steady-flow chemically-reactive engine, and set a framework to systematically identify maximum-efficiency engine architectures. - Highlights: • A unified thermodynamic model to study chemically-reactive engine architectures is developed. • All parametric analyses of efficiency are unified by two irreversibility-minimization principles. • Variations in internal energy transfers yield a net work increase that is greater than engine irreversibility reduced. • Variations in external energy transfers yield a net work increase that is lesser than engine irreversibility reduced

  5. Chemical Reactive Anchoring Lipids with Different Performance for Cell Surface Re-engineering Application

    Science.gov (United States)

    2018-01-01

    Introduction of selectively chemical reactive groups at the cell surface enables site-specific cell surface labeling and modification opportunity, thus facilitating the capability to study the cell surface molecular structure and function and the molecular mechanism it underlies. Further, it offers the opportunity to change or improve a cell’s functionality for interest of choice. In this study, two chemical reactive anchor lipids, phosphatidylethanolamine–poly(ethylene glycol)–dibenzocyclooctyne (DSPE–PEG2000–DBCO) and cholesterol–PEG–dibenzocyclooctyne (CHOL–PEG2000–DBCO) were synthesized and their potential application for cell surface re-engineering via lipid fusion were assessed with RAW 264.7 cells as a model cell. Briefly, RAW 264.7 cells were incubated with anchor lipids under various concentrations and at different incubation times. The successful incorporation of the chemical reactive anchor lipids was confirmed by biotinylation via copper-free click chemistry, followed by streptavidin-fluorescein isothiocyanate binding. In comparison, the cholesterol-based anchor lipid afforded a higher cell membrane incorporation efficiency with less internalization than the phospholipid-based anchor lipid. Low cytotoxicity of both anchor lipids upon incorporation into the RAW 264.7 cells was observed. Further, the cell membrane residence time of the cholesterol-based anchor lipid was evaluated with confocal microscopy. This study suggests the potential cell surface re-engineering applications of the chemical reactive anchor lipids. PMID:29503972

  6. The surface chemical reactivity of particles and its impact on human health

    Science.gov (United States)

    Setyan, A.; Sauvain, J. J.; Riediker, M.; Guillemin, M.; Rossi, M. J.

    2017-12-01

    The chemical composition of the particle-air interface is the gateway to chemical reactions of gases with condensed phase particles. It is of prime importance to understand the reactivity of particles and their interaction with surrounding gases, biological membranes, and solid supports. We used a Knudsen flow reactor to quantify functional groups on the surface of a few selected particle types. This technique is based on a heterogeneous titration reaction between a probe gas and a specific functional group on the particle surface. Six probe gases have been selected for the identification and quantification of important functional groups: N(CH3)3 for the titration of acidic sites, NH2OH for the detection of carbonyl functions (aldehydes and ketones) and/or oxidized sites owing to its strong reducing properties, CF3COOH and HCl for basic sites of different strength, O3 and NO2 for oxidizable groups. We also studied the kinetics of the reactions between particles and probe gases (uptake coefficient γ0). We tested the surface chemical composition and oxidation states of laboratory-generated aerosols (3 amorphous carbons, 2 flame soots, 2 Diesel particles, 2 secondary organic aerosols [SOA], 4 multiwall carbon nanotubes [MWCNT], 3 TiO2, and 2 metal salts) and of aerosols sampled in several bus depots. The sampling of particles in the bus depots was accompanied by the collection of urine samples of mechanics working full-time in these bus depots, and the quantification of 8-hydroxy-2'-deoxyguanosine, a biomarker of oxidative stress. The increase in oxidative stress biomarker levels over a working day was correlated (pcellular antioxidants.

  7. Chemical sensing underclothing system for testing PPE

    International Nuclear Information System (INIS)

    Slabotinsky, J.; Kralik, L.; Bradka, S.; Castulik, P.

    2009-01-01

    Personal protective equipment (PPE) when worn is subjected to pressure differentials across the garment due to ambient wind flow, by body movement and breathing creating the bellows effect, which may force hazardous chemicals vapor or aerosol through the closures, joints, outlet valves and/or clothing protective fabric. Thus the design, fit, size or improper donning of the protective garment will influence chemical-agent penetration. In order to determine penetration of chemical-protective garments by chemical vapor or aerosol, it is necessary to test the entire suit system, including seams, closures, outlet valves and areas of transition with other protective equipment, that is, at the ankles, waist, wrists, neck etc. In order to identify penetration of chemical vapor or aerosol through protective assembly, the Man-in-Simulant Test (MIST) with passive adsorptive devices (PADs) is used, when adsorbed challenging agent (simulant) is desorbed from the PAD and quantified. The current MIST method is failing in complexity of leak detection, due to limited number of passive collection points fixed on human body or a mannequin and very labor extensive work associated with allocation of 20-40 PADs and quantification of adsorbed agent. The Czech approach to detect and quantify penetration/permeation of chemical agent is based on chemical sensing underclothing enable to change the color when exposed with simulant or even with real CW agent. Color intensity and shape of stains on sensing fabric are processed with Laboratory Universal Computer Image Analysis (LUCIA) allowing determining the quantity and the allocation of the penetrating noxious agent(s). This method allows for example calculate individual doses of exposure, the breakthrough coefficient of protective garment as whole and uniquely precise allocation of penetration/permeation shortfalls. Presentation is providing detailed description of imaging system with nickname 'LUCY' in combination with testing mannequin

  8. Chemical Pathology Laboratory Tests in Pregnancy | Bolarin ...

    African Journals Online (AJOL)

    Thus, chemical pathology laboratory investigative test results during normal healthy pregnancy show significant differences from the normal reference intervals or ranges (i.e. non-pregnant woman's reference intervals or ranges) thereby causing misinterpretation as inappropriate or odd. This wrong interpretation of the ...

  9. Fast screening of analytes for chemical reactions by reactive low-temperature plasma ionization mass spectrometry.

    Science.gov (United States)

    Zhang, Wei; Huang, Guangming

    2015-11-15

    Approaches for analyte screening have been used to aid in the fine-tuning of chemical reactions. Herein, we present a simple and straightforward analyte screening method for chemical reactions via reactive low-temperature plasma ionization mass spectrometry (reactive LTP-MS). Solution-phase reagents deposited on sample substrates were desorbed into the vapor phase by action of the LTP and by thermal desorption. Treated with LTP, both reagents reacted through a vapor phase ion/molecule reaction to generate the product. Finally, protonated reagents and products were identified by LTP-MS. Reaction products from imine formation reaction, Eschweiler-Clarke methylation and the Eberlin reaction were detected via reactive LTP-MS. Products from the imine formation reaction with reagents substituted with different functional groups (26 out of 28 trials) were successfully screened in a time of 30 s each. Besides, two short-lived reactive intermediates of Eschweiler-Clarke methylation were also detected. LTP in this study serves both as an ambient ionization source for analyte identification (including reagents, intermediates and products) and as a means to produce reagent ions to assist gas-phase ion/molecule reactions. The present reactive LTP-MS method enables fast screening for several analytes from several chemical reactions, which possesses good reagent compatibility and the potential to perform high-throughput analyte screening. In addition, with the detection of various reactive intermediates (intermediates I and II of Eschweiler-Clarke methylation), the present method would also contribute to revealing and elucidating reaction mechanisms. Copyright © 2015 John Wiley & Sons, Ltd.

  10. Chemical reactivity of analogous technetium(V) and rhenium(V) dioxo complexes

    International Nuclear Information System (INIS)

    Kremer, C.; Kremer, E.; Leon, A.

    1993-01-01

    All complexes of the series [MO 2 L 2 ] + (M = Tc, Re, L = ethylenediamine (en), 1,3-diaminopropane (1,3-dap)) have been synthesized and their chemical reactivities investigated. The following properties were studied: stability of the aqueous solutions at different pH values, substitution kinetics, lipophilicity and protein binding. The complexes show very similar reactivity in aqueous solution. From a radiopharmaceutical point of view, no significant difference in their in vivo behavior is expected. (author) 12 refs.; 1 fig.; 3 tabs

  11. Chemical reactivity of potential ferrocyanide precipitates in Hanford tanks with nitrates and nitrites

    International Nuclear Information System (INIS)

    Scheele, R.D.; Burger, L.L.; Tingey, J.M.; Hallen, R.T.; Lilga, M.A.

    1992-01-01

    Ferrocyanide-bearing wastes were produced at the Hanford Site during the 1950s. Safe storage of these wastes has recently drawn increased attention. As a result of these concerns, the Pacific Northwest Laboratory was chartered to investigate the chemical reactivity and explosivity of the ferrocyanide-bearing wastes. We have investigated the thermal sensitivity of synthetic wastes and ferrocyanides and observed oxidation at 130 deg. C and explosions down to 295 deg. C. Coupled with thermodynamic calculations, these thermal studies have also shown a dependence of the reactivity on the synthetic waste composition, which is dependent on the solids settling behavior. (author)

  12. Self-organised synthesis of Rh nanostructures with tunable chemical reactivity

    Directory of Open Access Journals (Sweden)

    Lizzit S

    2007-01-01

    Full Text Available AbstractNonequilibrium periodic nanostructures such as nanoscale ripples, mounds and rhomboidal pyramids formed on Rh(110 are particularly interesting as candidate model systems with enhanced catalytic reactivity, since they are endowed with steep facets running along nonequilibrium low-symmetry directions, exposing a high density of undercoordinated atoms. In this review we report on the formation of these novel nanostructured surfaces, a kinetic process which can be controlled by changing parameters such as temperature, sputtering ion flux and energy. The role of surface morphology with respect to chemical reactivity is investigated by analysing the carbon monoxide dissociation probability on the different nanostructured surfaces.

  13. Computational Study of Chemical Reactivity Using Information-Theoretic Quantities from Density Functional Reactivity Theory for Electrophilic Aromatic Substitution Reactions.

    Science.gov (United States)

    Wu, Wenjie; Wu, Zemin; Rong, Chunying; Lu, Tian; Huang, Ying; Liu, Shubin

    2015-07-23

    The electrophilic aromatic substitution for nitration, halogenation, sulfonation, and acylation is a vastly important category of chemical transformation. Its reactivity and regioselectivity is predominantly determined by nucleophilicity of carbon atoms on the aromatic ring, which in return is immensely influenced by the group that is attached to the aromatic ring a priori. In this work, taking advantage of recent developments in quantifying nucleophilicity (electrophilicity) with descriptors from the information-theoretic approach in density functional reactivity theory, we examine the reactivity properties of this reaction system from three perspectives. These include scaling patterns of information-theoretic quantities such as Shannon entropy, Fisher information, Ghosh-Berkowitz-Parr entropy and information gain at both molecular and atomic levels, quantitative predictions of the barrier height with both Hirshfeld charge and information gain, and energetic decomposition analyses of the barrier height for the reactions. To that end, we focused in this work on the identity reaction of the monosubstituted-benzene molecule reacting with hydrogen fluoride using boron trifluoride as the catalyst in the gas phase. We also considered 19 substituting groups, 9 of which are ortho/para directing and the other 9 meta directing, besides the case of R = -H. Similar scaling patterns for these information-theoretic quantities found for stable species elsewhere were disclosed for these reactions systems. We also unveiled novel scaling patterns for information gain at the atomic level. The barrier height of the reactions can reliably be predicted by using both the Hirshfeld charge and information gain at the regioselective carbon atom. The energy decomposition analysis ensued yields an unambiguous picture about the origin of the barrier height, where we showed that it is the electrostatic interaction that plays the dominant role, while the roles played by exchange-correlation and

  14. RICE: a computer program for multicomponent chemically reactive flows at all speeds

    International Nuclear Information System (INIS)

    Rivard, W.C.; Farmer, O.A.; Butler, T.D.

    1974-11-01

    The fluid dynamics of chemically reactive mixtures are calculated at arbitrary flow speeds with the RICE program. The dynamics are governed by the two-dimensional, time-dependent Navier-Stokes equations together with the species transport equations and the mass-action rate equations for the chemical reactions. The mass and momentum equations for the mixture are solved implicitly by the ICE technique. The equations for total energy and species transport are solved explicitly while the chemical rate equations are solved implicitly with a time step that may be a submultiple of the hydrodynamic time step. Application is made to continuous wave HF chemical lasers to compute the supersonic mixing and chemical reactions that take place in the lasing cavity. (U.S.)

  15. Advanced Chemical Reduction of Reduced Graphene Oxide and Its Photocatalytic Activity in Degrading Reactive Black 5

    Directory of Open Access Journals (Sweden)

    Christelle Pau Ping Wong

    2015-10-01

    Full Text Available Textile industries consume large volumes of water for dye processing, leading to undesirable toxic dyes in water bodies. Dyestuffs are harmful to human health and aquatic life, and such illnesses as cholera, dysentery, hepatitis A, and hinder the photosynthetic activity of aquatic plants. To overcome this environmental problem, the advanced oxidation process is a promising technique to mineralize a wide range of dyes in water systems. In this work, reduced graphene oxide (rGO was prepared via an advanced chemical reduction route, and its photocatalytic activity was tested by photodegrading Reactive Black 5 (RB5 dye in aqueous solution. rGO was synthesized by dispersing the graphite oxide into the water to form a graphene oxide (GO solution followed by the addition of hydrazine. Graphite oxide was prepared using a modified Hummers’ method by using potassium permanganate and concentrated sulphuric acid. The resulted rGO nanoparticles were characterized using ultraviolet-visible spectrophotometry (UV-Vis, X-ray powder diffraction (XRD, Raman, and Scanning Electron Microscopy (SEM to further investigate their chemical properties. A characteristic peak of rGO-48 h (275 cm−1 was observed in the UV spectrum. Further, the appearance of a broad peak (002, centred at 2θ = 24.1°, in XRD showing that graphene oxide was reduced to rGO. Based on our results, it was found that the resulted rGO-48 h nanoparticles achieved 49% photodecolorization of RB5 under UV irradiation at pH 3 in 60 min. This was attributed to the high and efficient electron transport behaviors of rGO between aromatic regions of rGO and RB5 molecules.

  16. Thermal chemical-mechanical reactive flow model of shock initiation in solid explosives

    International Nuclear Information System (INIS)

    Nicholls, A.L. III; Tarver, C.M.

    1998-01-01

    The three dimensional Arbitrary Lagrange Eulerian hydrodynamic computer code ALE3D with fully coupled thermal-chemical-mechanical material models provides the framework for the development of a physically realistic model of shock initiation and detonation of solid explosives. The processes of hot spot formation during shock compression, subsequent ignition of reaction or failure to react, growth of reaction in individual hot spots, and coalescence of reacting hot spots during the transition to detonation can now be modeled using Arrhenius chemical kinetic rate laws and heat transfer to propagate the reactive flow. This paper discusses the growth rates of reacting hot spots in HMX and TATB and their coalescence during shock to detonation transition. Hot spot deflagration rates are found to be fast enough to consume explosive particles less than 10 mm in diameter during typical shock duration times, but larger particles must fragment and create more reactive surface area in order to be rapidly consumed

  17. The chemical reactivity and structure of collagen studied by neutron diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Wess, T.J.; Wess, L.; Miller, A. [Univ. of Stirling (United Kingdom)

    1994-12-31

    The chemical reactivity of collagen can be studied using neutron diffraction (a non-destructive technique), for certain reaction types. Collagen contains a number of lysine and hydroxylysine side chains that can react with aldehydes and ketones, or these side chains can themselves be converted to aldehydes by lysyl oxidase. The reactivity of these groups not only has an important role in the maintenance of mechanical strength in collagen fibrils, but can also manifest pathologically in the cases of aging, diabetes (reactivity with a variety of sugars) and alcoholism (reactivity with acetaldehyde). The reactivity of reducing groups with collagen can be studied by neutron diffraction, since the crosslink formed in the adduction process is initially of a Schiff base or keto-imine nature. The nature of this crosslink allows it to be deuterated, and the position of this relatively heavy scattering atom can be used in a process of phase determination by multiple isomorphous replacement. This process was used to study the following: the position of natural crosslinks in collagen; the position of adducts in tendon from diabetic rats in vivo and the in vitro position of acetaidehyde adducts in tendon.

  18. The chemical reactivity and structure of collagen studied by neutron diffraction

    International Nuclear Information System (INIS)

    Wess, T.J.; Wess, L.; Miller, A.

    1994-01-01

    The chemical reactivity of collagen can be studied using neutron diffraction (a non-destructive technique), for certain reaction types. Collagen contains a number of lysine and hydroxylysine side chains that can react with aldehydes and ketones, or these side chains can themselves be converted to aldehydes by lysyl oxidase. The reactivity of these groups not only has an important role in the maintenance of mechanical strength in collagen fibrils, but can also manifest pathologically in the cases of aging, diabetes (reactivity with a variety of sugars) and alcoholism (reactivity with acetaldehyde). The reactivity of reducing groups with collagen can be studied by neutron diffraction, since the crosslink formed in the adduction process is initially of a Schiff base or keto-imine nature. The nature of this crosslink allows it to be deuterated, and the position of this relatively heavy scattering atom can be used in a process of phase determination by multiple isomorphous replacement. This process was used to study the following: the position of natural crosslinks in collagen; the position of adducts in tendon from diabetic rats in vivo and the in vitro position of acetaidehyde adducts in tendon

  19. Patch test reactivity to feverfew-containing creams in feverfew-allergic patients

    DEFF Research Database (Denmark)

    Paulsen, Evy; Christensen, Lars P; Fretté, Xavier

    2010-01-01

    with feverfew contact allergy were patch tested with two creams containing the feverfew extract. Subsequently, the creams were analysed by liquid chromatography with tandem mass spectrometry to detect parthenolide. Results: Four of the patients tested positive to one of the creams; reactivity was associated......-sensitive patients. The reactivity may be enhanced by simultaneous testing with parthenolide, but the reactivity is lost over time, probably because of degradation of parthenolide....

  20. Test on the reactor with the portable digital reactivity meter for physical experiment

    International Nuclear Information System (INIS)

    Huang Liyuan

    2010-01-01

    Test must be performed on the zero power reactor During the development of portable digital reactivity meter for physical experiment, in order to check its measurement function and accuracy. It describes the test facility, test core, test methods, test items and test results. The test results show that the instrument satisfy the requirements of technical specification, and satisfy the reactivity measurement in the physical experiments on reactors. (authors)

  1. VHTRC experiment for verification test of H∞ reactivity estimation method

    International Nuclear Information System (INIS)

    Fujii, Yoshio; Suzuki, Katsuo; Akino, Fujiyoshi; Yamane, Tsuyoshi; Fujisaki, Shingo; Takeuchi, Motoyoshi; Ono, Toshihiko

    1996-02-01

    This experiment was performed at VHTRC to acquire the data for verifying the H∞ reactivity estimation method. In this report, the experimental method, the measuring circuits and data processing softwares are described in details. (author)

  2. Evaluation of a high-throughput peptide reactivity format assay for assessment of the skin sensitization potential of chemicals

    Directory of Open Access Journals (Sweden)

    Chin Lin eWong

    2016-03-01

    Full Text Available The direct peptide reactivity assay (DPRA is a validated method for in vitro assessment of the skin sensitization potential of chemicals. In the present work, we describe a peptide reactivity assay using 96-well plate format and systematically identified the optimal assay conditions for accurate and reproducible classification of chemicals with known sensitizing capacity. The aim of the research is to ensure that the analytical component of the peptide reactivity assay is robust, accurate and reproducible in accordance with criteria that are used for the validation of bioanalytical methods. Analytical performance was evaluated using quality control samples (QCs; heptapeptides at low, medium and high concentrations and incubation of control chemicals (chemicals with known sensitization capacity, weak, moderate, strong, extreme and non-sensitizers with each of three synthetic heptapeptides, viz Cor1-C420 (Ac-NKKCDLF, cysteine- (Ac-RFAACAA and lysine- (Ac-RFAAKAA containing heptapeptides. The optimal incubation temperature for all three heptapeptides was 25°C. Apparent heptapeptide depletion was affected by vial material composition. Incubation of test chemicals with Cor1-C420, showed that peptide depletion was unchanged in polypropylene vials over 3-days storage in an autosampler but this was not the case for borosilicate glass vials. For cysteine-containing heptapeptide, the concentration was not stable by day 3 post-incubation in borosilicate glass vials. Although the lysine-containing heptapeptide concentration was unchanged in both polypropylene and borosilicate glass vials, the apparent extent of lysine-containing heptapeptide depletion by ethyl acrylate, differed between polypropylene (24.7% and glass (47.3% vials. Additionally, the peptide-chemical complexes for Cor1-C420-cinnamaldehyde and cysteine-containing heptapeptide-2,4-dinitrochlorobenzene were partially reversible during 3-days of autosampler storage. These observations further

  3. Reactive chemically modified piezoelectric crystal detectors: A new class of high-selectivity sensors

    International Nuclear Information System (INIS)

    Fadeev, A.Yu.; Filatov, A.L.; Lisichkin, G.V.

    1994-01-01

    A great number of works have focused on the study of properties of modified piezoelectric quartz crystal detectors (PQCDs) coated with sorbing substrates and on applying sensors based on them for the analysis of diluted gas mixtures and solutions. This work offers a new class of gravemetric sensors characterized by a reversible chemical reaction that occurs on their surface. Silica films are proposed as a sorbing coating of quartz detectors, and a chemical modification of a surface is suggested for covalent fixation of the necessary compounds. PQCDs were chemically modified with reactive diene derivatives that can also act as dienophiles. Hexachlorocyclopentadiene (HCCPD, resonater I) and cyclopentadiene (CPD, resonator II) were fixed on a PQCD surface in several stages. After treatment with the resonaters, the PQCD in a CPD gas phase exhibited time dependent frequency shifts from 20-100 Hz. The results suggest that there is a reversible chemical reaction on the electrode surface of resonators I and II when they interact with CPD vapors. Therefore, PQCDs modified with reactive dienes were prepared for the first time and may be employed as selective sensors for CPD

  4. Automated chemical kinetic modeling via hybrid reactive molecular dynamics and quantum chemistry simulations.

    Science.gov (United States)

    Döntgen, Malte; Schmalz, Felix; Kopp, Wassja A; Kröger, Leif C; Leonhard, Kai

    2018-06-13

    An automated scheme for obtaining chemical kinetic models from scratch using reactive molecular dynamics and quantum chemistry simulations is presented. This methodology combines the phase space sampling of reactive molecular dynamics with the thermochemistry and kinetics prediction capabilities of quantum mechanics. This scheme provides the NASA polynomial and modified Arrhenius equation parameters for all species and reactions that are observed during the simulation and supplies them in the ChemKin format. The ab initio level of theory for predictions is easily exchangeable and the presently used G3MP2 level of theory is found to reliably reproduce hydrogen and methane oxidation thermochemistry and kinetics data. Chemical kinetic models obtained with this approach are ready-to-use for, e.g., ignition delay time simulations, as shown for hydrogen combustion. The presented extension of the ChemTraYzer approach can be used as a basis for methodologically advancing chemical kinetic modeling schemes and as a black-box approach to generate chemical kinetic models.

  5. Experiment data report for Test RIA 1-2 (Reactivity Initiated Accident Test Series)

    International Nuclear Information System (INIS)

    Zimmermann, C.L.; White, C.E.; Evans, R.P.

    1979-06-01

    Recorded test data are presented for the second of six planned tests in the Reactivity Initiated Accident (RIA) Test Series I, Test RIA 1-2. This test, conducted at the Power Burst Facility, had the following objectives: (1) characterize the response of preirradiated fuel rods during an RIA event conducted at boiling water reactor hot-startup conditions; and (2) evaluate the effect of rod internal pressure on preirradiated fuel rod response during an RIA event. The data from Test RIA 1-2 are graphed in engineering units and have been appraised for quality and validity. These uninterpreted data are presented for use in the nuclear fuel behavior research field before detailed analysis and interpretation have been completed

  6. Ultraviolet light photobiology of the protozoan Tetrahymena pyriformis and chemical reactivation of DNA damage

    International Nuclear Information System (INIS)

    Wheeler, J.S.

    1988-01-01

    The tunable dye laser was developed in order to perform UV-B and UV-C (254-320 nm) action spectra studies on several different organisms. Using the laser, action spectra studies have been performed for Escherichia coli, Saccharomyces, Chlamydomonas, Caenorhabditis elegans, Paramecium, and Tetrahymena pyriformis. Studies generally indicate increasing LD 50 values with increasing wavelength. Two notable findings were made: (1) The action spectra does not follow the DNA absorption spectra at 280, 290 and 295 nm; (2) The repair competent/repair defective sensitization factor does not remain constant throughout the wavelength region. In addition it was found that the repair defective strain of E. coli, Bs-1, showed an increase in survival with increasing UV irradiation, at certain dose levels. Further experiments were designed to better characterize the reactivation. Tetrahymena were exposed to UV-C and reactivated with methyl methanesulfonate (MMS) and 4-nitro quinoline oxide (4-NQO). In both cases survival was seen to increase after chemical exposure. Likewise, UV-C was found to reactivate chemical damage (MMS)

  7. Properties of amorphous silicon thin films synthesized by reactive particle beam assisted chemical vapor deposition

    International Nuclear Information System (INIS)

    Choi, Sun Gyu; Wang, Seok-Joo; Park, Hyeong-Ho; Jang, Jin-Nyoung; Hong, MunPyo; Kwon, Kwang-Ho; Park, Hyung-Ho

    2010-01-01

    Amorphous silicon thin films were formed by chemical vapor deposition of reactive particle beam assisted inductively coupled plasma type with various reflector bias voltages. During the deposition, the substrate was heated at 150 o C. The effects of reflector bias voltage on the physical and chemical properties of the films were systematically studied. X-ray diffraction and Raman spectroscopy results showed that the deposited films were amorphous and the films under higher reflector voltage had higher internal energy to be easily crystallized. The chemical state of amorphous silicon films was revealed as metallic bonding of Si atoms by using X-ray photoelectron spectroscopy. An increase in reflector voltage induced an increase of surface morphology of films and optical bandgap and a decrease of photoconductivity.

  8. THE INTEGRATED USE OF COMPUTATIONAL CHEMISTRY, SCANNING PROBE MICROSCOPY, AND VIRTUAL REALITY TO PREDICT THE CHEMICAL REACTIVITY OF ENVIRONMENTAL SURFACES

    Science.gov (United States)

    In the last decade three new techniques scanning probe microscopy (SPM), virtual reality (YR) and computational chemistry ave emerged with the combined capability of a priori predicting the chemically reactivity of environmental surfaces. Computational chemistry provides the cap...

  9. Model-Based Testing of a Reactive System with Coloured Petri Nets

    DEFF Research Database (Denmark)

    Tjell, Simon

    2006-01-01

    In this paper, a reactive and nondeterministic system is tested. This is doneby applying a generic model that has been specified as a configurable Coloured PetriNet. In this way, model-based testing is possible for a wide class of reactive system atthe level of discrete events. Concurrently...

  10. Electroencephalographic reactivity testing in unconscious patients: a systematic review of methods and definitions

    NARCIS (Netherlands)

    Admiraal, M. M.; van Rootselaar, A.-F.; Horn, J.

    2017-01-01

    Electroencephalographic (EEG) reactivity testing is often presented as a clear-cut element of electrophysiological testing. Absence of EEG reactivity is generally considered an indicator of poor outcome, especially in patients after cardiac arrest. However, guidelines do not clearly describe how to

  11. Responses of human birch pollen allergen-reactive T cells to chemically modified allergens (allergoids).

    Science.gov (United States)

    Dormann, D; Ebner, C; Jarman, E R; Montermann, E; Kraft, D; Reske-Kunz, A B

    1998-11-01

    Allergoids are widely used in specific immunotherapy for the treatment of IgE-mediated allergic diseases. The aim of this study was to analyse whether a modification of birch pollen allergens with formaldehyde affects the availability of T-cell epitopes. Efficient modification of the allergens was verified by determining IgE and IgG binding activity using ELISA inhibition tests. T-cell responses to birch pollen allergoids were analysed in polyclonal systems, using peripheral blood mononuclear cells (PBMC) of five birch pollen-allergic individuals, as well as birch pollen extract-reactive T-cell lines (TCL), established from the peripheral blood of 14 birch pollen-allergic donors. To determine whether the modification of natural (n)Bet v 1 with formaldehyde or maleic anhydride results in epitope-specific changes in T-cell reactivities, 22 Bet v 1-specific T-cell clones (TCC), established from nine additional birch pollen-allergic individuals, were tested for their reactivity with these products. The majority of PBMC and TCL showed a reduced response to the birch pollen extract allergoid. Bet v 1-specific TCC could be divided into allergoid-reactive and -non-reactive TCC. No simple correlation between possible modification sites of formaldehyde in the respective T-cell epitopes and the stimulatory potential of the allergoid was observed. Mechanisms of suppression or of anergy induction were excluded as an explanation for the non-reactivity of representative TCC. All TCC could be stimulated by maleylated and unmodified nBet v 1 to a similar extent. These results demonstrate differences in the availability of T-cell epitopes between allergoids and unmodified allergens, which are most likely due to structural changes within the allergen molecule.

  12. Thermogravimetric study on the influence of structural, textural and chemical properties of biomass chars on CO2 gasification reactivity

    International Nuclear Information System (INIS)

    Bouraoui, Zeineb; Jeguirim, Mejdi; Guizani, Chamseddine; Limousy, Lionel; Dupont, Capucine; Gadiou, Roger

    2015-01-01

    The present investigation aims to examine the influence of textural, structural and chemical properties of biomass chars on the CO 2 gasification rate. Various lignocellulosic biomass chars were prepared under the same conditions. Different analytical techniques were used to determine the char properties such as Scanning Electronic Microscopy, nitrogen adsorption manometry, Raman spectroscopy and X Ray Fluorescence. Gasification tests were carried out in a thermobalance under 20% CO 2 in nitrogen at 800 °C. Significant differences of the total average reactivity were observed with a factor of 2 between the prepared chars. Moreover, different behaviors of gasification rate profiles versus conversion were obtained. This difference of behavior appeared to be correlated with the biomass char properties. Hence, up to 70% of conversion, the gasification rate was shown to depend on the char external surface and the potassium content. At higher conversion ratio, a satisfactory correlation between the Catalytic Index and the average gasification rate was identified. The results highlight the importance of knowing both textural and structural properties and mineral contents of biomass chars to predict fuel reactivity during CO 2 gasification processes. Such behavior prediction is highly important in the gasifiers design for char conversion. - Highlights: • CO 2 gasification reactivity of various lignocellulosic chars were examined. • Chars properties affect strongly samples gasification behavior. • Initial gasification rate is affected by external surface, K content and D3/G ratio. • Gasification rate behavior depends on the Alkali index at high conversion

  13. Prediction of monomer reactivity in radical copolymerizations from transition state quantum chemical descriptors

    Directory of Open Access Journals (Sweden)

    Zhengde Tan

    2013-01-01

    Full Text Available In comparison with the Q-e scheme, the Revised Patterns Scheme: the U, V Version (the U-V scheme has greatly improved both its accessibility and its accuracy in interpreting and predicting the reactivity of a monomer in free-radical copolymerizations. Quantitative structure-activity relationship (QSAR models were developed to predict the reactivity parameters u and v of the U-V scheme, by applying genetic algorithm (GA and support vector machine (SVM techniques. Quantum chemical descriptors used for QSAR models were calculated from transition state species with structures C¹H3 - C²HR³• or •C¹H2 - C²H2R³ (formed from vinyl monomers C¹H²=C²HR³ + H•, using density functional theory (DFT, at the UB3LYP level of theory with 6-31G(d basis set. The optimum support vector regression (SVR model of the reactivity parameter u based on Gaussian radial basis function (RBF kernel (C = 10, ε = 10- 5 and γ = 1.0 produced root-mean-square (rms errors for the training, validation and prediction sets being 0.220, 0.326 and 0.345, respectively. The optimal SVR model for v with the RBF kernel (C = 20, ε = 10- 4 and γ = 1.2 produced rms errors for the training set of 0.123, the validation set of 0.206 and the prediction set of 0.238. The feasibility of applying the transition state quantum chemical descriptors to develop SVM models for reactivity parameters u and v in the U-V scheme has been demonstrated.

  14. Feasibility Study for the Use of Green, Bio-Based, Efficient Reactive Sorbent Material to Neutralize Chemical Warfare Agents

    Science.gov (United States)

    2012-08-02

    REPORT Feasibility study for the use of green, bio-based, efficient reactive sorbent material to neutralize chemical warfare agents 14. ABSTRACT 16...way cellulose, lignin and hemicelluloses interact as well as whole wood dissolution occurs in ILs. The present project was conducted to 1. REPORT...Feasibility study for the use of green, bio-based, efficient reactive sorbent material to neutralize chemical warfare agents Report Title ABSTRACT Over the

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1997-07-01

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

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

    Science.gov (United States)

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

    2017-12-01

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

  17. 46 CFR 4.03-7 - Chemical test.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 1 2010-10-01 2010-10-01 false Chemical test. 4.03-7 Section 4.03-7 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY PROCEDURES APPLICABLE TO THE PUBLIC MARINE CASUALTIES AND INVESTIGATIONS Definitions § 4.03-7 Chemical test. The term chemical test means a scientifically recognized test...

  18. Chemical Reactivity and Spectroscopy Explored From QM/MM Molecular Dynamics Simulations Using the LIO Code

    Directory of Open Access Journals (Sweden)

    Juan P. Marcolongo

    2018-03-01

    Full Text Available In this work we present the current advances in the development and the applications of LIO, a lab-made code designed for density functional theory calculations in graphical processing units (GPU, that can be coupled with different classical molecular dynamics engines. This code has been thoroughly optimized to perform efficient molecular dynamics simulations at the QM/MM DFT level, allowing for an exhaustive sampling of the configurational space. Selected examples are presented for the description of chemical reactivity in terms of free energy profiles, and also for the computation of optical properties, such as vibrational and electronic spectra in solvent and protein environments.

  19. Chemical reactivity and spectroscopy explored from QM/MM molecular dynamics simulations using the LIO code

    Science.gov (United States)

    Marcolongo, Juan P.; Zeida, Ari; Semelak, Jonathan A.; Foglia, Nicolás O.; Morzan, Uriel N.; Estrin, Dario A.; González Lebrero, Mariano C.; Scherlis, Damián A.

    2018-03-01

    In this work we present the current advances in the development and the applications of LIO, a lab-made code designed for density functional theory calculations in graphical processing units (GPU), that can be coupled with different classical molecular dynamics engines. This code has been thoroughly optimized to perform efficient molecular dynamics simulations at the QM/MM DFT level, allowing for an exhaustive sampling of the configurational space. Selected examples are presented for the description of chemical reactivity in terms of free energy profiles, and also for the computation of optical properties, such as vibrational and electronic spectra in solvent and protein environments.

  20. SCTI chemical leak detection test plan

    International Nuclear Information System (INIS)

    1981-01-01

    Tests will be conducted on the CRBRP prototype steam generator at SCTI to determine the effects of steam generator geometry on the response of the CRBRP chemical leak detection system to small water-to-sodium leaks in various regions of the steam generator. Specifically, small injections of hydrogen gas (simulating water leaks) will be made near the two tubesheets, and the effective transport times to the main stream exit and vent line hydrogen meters will be measured. The magnitude and time characteristics of the meters' response will also be measured. This information will be used by the Small Leak Protection Base Program (SG027) for improved predictions of meter response times and leak detection sensitivity

  1. Reactivity initiated accident test series Test RIA 1-4 fuel behavior report

    International Nuclear Information System (INIS)

    Cook, B.A.; Martinson, Z.R.

    1984-09-01

    This report presents and discusses results from the final test in the Reactivity Initiated Accident (RIA) Test Series, Test RIA 1-4, conducted in the Power Burst Facility (PBF) at the Idaho National Engineering Laboratory. Nine preirradiated fuel rods in a 3 x 3 bundle configuration were subjected to a power burst while at boiling water reactor hot-startup system conditions. The test resulted in estimated axial peak, radial average fuel enthalpies of 234 cal/g UO 2 on the center rod, 255 cal/g UO 2 on the side rods, and 277 cal/g UO 2 on the corner rods. Test RIA 1-4 was conducted to investigate fuel coolability and channel blockage within a bundle of preirradiated rods near the present enthalpy limit of 280 cal/g UO 2 established by the US Nuclear Regulatory Commission. The test design and conduct are described, and the bundle and individual rod thermal and mechanical responses are evaluated. Conclusions from this final test and the entire PBF RIA Test Series are presented

  2. The influence of condensed tannin structure on rate of microbial mineralization and reactivity to chemical assays.

    Science.gov (United States)

    Norris, Charlotte E; Preston, Caroline M; Hogg, Karen E; Titus, Brian D

    2011-03-01

    We examined how tannin structure influences reactivity in tannin assays and carbon and nitrogen mineralization. Condensed tannins from the foliage of ten tree and shrub species and from pecan shells (Carya illinoensis) had different proportions of: (a) epicatechin (cis) and catechin (trans) isomers, (b) procyanidin (PC) and prodelphinidin (PD) monomers, and (c) different chain lengths. The response of each tannin to several widely used tannin assays was determined. Although there was some variation in response to proanthocyanidin (butanol/HCl) and Folin Ciocalteu assays, we did not deduce any predictable relationship between tannin structure and response to either assay. There was little variation in protein precipitation among the different tannins. To assess biological activity, six of the tannins were incubated with forest humus for 22 days. We determined that, while PC-based tannins remained at least partly extractable for the duration of the incubation, tannins with a high proportion of PD subunits rapidly became unextractable from soil. There was a positive correlation between net nitrogen mineralization and cis chemical structure. Carbon mineralization was enhanced initially by the addition of tannins to humus, but after 22 days, a negative correlation between the proportion of cis subunits and respiration was determined. Overall, we were not able to demonstrate consistent effects of structure on either microbial mineralization or reactivity to chemical assays; such relationships remain elusive.

  3. Chemical cleaning specification: few tube test model

    International Nuclear Information System (INIS)

    Hampton, L.V.; Simpson, J.L.

    1979-09-01

    The specification is for the waterside chemical cleaning of the 2 1/4 Cr - 1 Mo steel steam generator tubes. It describes the reagents and conditions for post-chemical cleaning passivation of the evaporator tubes

  4. Young Investigator Proposal, Research Area 7.4 Reactive Chemical Systems: Multifunctional, Bimetallic Nanomaterials Prepared by Atomic Layer Electroless Deposition

    Science.gov (United States)

    2017-09-30

    Report: Young Investigator Proposal, Research Area 7.4 Reactive Chemical Systems: Multifunctional, Bimetallic Nanomaterials Prepared by Atomic Layer ...Chemical Systems: Multifunctional, Bimetallic Nanomaterials Prepared by Atomic Layer Electroless Deposition Report Term: 0-Other Email: pcappillino... Layer Electroless Deposition (ALED, Figure 1) is the ability to tune growth mechanism, hence growth morphology, by altering conditions. In this

  5. Efficient modeling of reactive transport phenomena by a multispecies random walk coupled to chemical equilibrium

    International Nuclear Information System (INIS)

    Pfingsten, W.

    1996-01-01

    Safety assessments for radioactive waste repositories require a detailed knowledge of physical, chemical, hydrological, and geological processes for long time spans. In the past, individual models for hydraulics, transport, or geochemical processes were developed more or less separately to great sophistication for the individual processes. Such processes are especially important in the near field of a waste repository. Attempts have been made to couple at least two individual processes to get a more adequate description of geochemical systems. These models are called coupled codes; they couple predominantly a multicomponent transport model with a chemical reaction model. Here reactive transport is modeled by the sequentially coupled code MCOTAC that couples one-dimensional advective, dispersive, and diffusive transport with chemical equilibrium complexation and precipitation/dissolution reactions in a porous medium. Transport, described by a random walk of multispecies particles, and chemical equilibrium calculations are solved separately, coupled only by an exchange term. The modular-structured code was applied to incongruent dissolution of hydrated silicate gels, to movement of multiple solid front systems, and to an artificial, numerically difficult heterogeneous redox problem. These applications show promising features with respect to applicability to relevant problems and possibilities of extensions

  6. Volatility of fragrance chemicals: patch testing implications.

    Science.gov (United States)

    Gilpin, Sarah J; Hui, Xiaoying; Maibach, Howard I

    2009-01-01

    Diagnostic and predictive patch testing to determine contact allergy due to fragrance materials requires applying a fixed dose of material to the skin. This dose can be affected by the volatile nature of fragrances; little data exist on how the loss of fragrance dose due to volatility affects patch testing. (1) To evaluate pH dependence and evaporation rates of two fragrance chemicals, geraniol, citronellol, and a common fragrance solvent, diethyl phthalate (DEP) and (2) Assess implications for predictive patch-testing methods for fragrances. pH analysis of each material at 1% for three values (4.0, 5.0, 7.0) was done over 40 hours. Volatility experiments for each material, nonradiolabeled and radiolabeled, were conducted over a 24-hour period, taking readings at six time points (5 minutes, 15 minutes, 40 minutes, 1 hour, 3 hours, and 24 hours). Evaporation rates were not sensitive to pH shifts from 4.0 to 7.0. Evaporation rates for nonradiolabeled materials were low: after 24 hours, geraniol lost 8.9%, citronellol 27.0% and DEP 14.5%. The volatility data for radiolabeled materials demonstrated that geraniol loses up to 39% of its dose, citronellol loses up to 26%, and DEP up to 14% within 40 minutes. The tendency of fragrance materials to evaporate can impact the dose being applied to the patch and therefore the result of the patch and ultimately the decision-making process regarding that fragrance material's safety. These data, developed with DEP, utilized in a predictive sensitization assay cannot be generalized.

  7. Chemical composition and photochemical reactivity of exhaust from aircraft turbine engines

    Directory of Open Access Journals (Sweden)

    T. F. Lyon

    Full Text Available Assessment of the environmental impact of aircraft emissions is required by planners and policy makers. Seveal areas of concern are: 1. exposure of airport workers and urban residents to toxic chemicals emitted when the engines operate at low power (idle and taxi on the ground; 2. contributions to urban photochemical air pollution of aircraft volatile organic and nitrogen oxides emissions from operations around airports; and 3. emissions of nitrogen oxides and particles during high-altitude operation. The environmental impact of chemicals emitted from jet aircraft turbine engines has not been firmly established due to lack of data regarding emission rates and identities of the compounds emitted. This paper describes an experimental study of two different aircraft turbine engines designed to determine detailed organic emissions, as well as emissions of inorganic gases. Emissions were measured at several engine power settings. Measurements were made of detailed organic composition from C1 through C17, CO, CO2, NO, NOx, and polycyclic aromatic hydrocarbons. Measurements were made using a multi-port sampling pro be positioned directly behind the engine in the exhaust exit plane. The emission measurements have been used to determine the organic distribution by carbon number and the distribution by compound class at each engine power level. The sum of the organic species was compared with an independent measurement of total organic carbon to assess the carbon mass balance. A portion of the exhaust was captured and irradiated in outdoor smog chambers to assess the photochemical reactivity of the emissions with respect to ozone formation. The reactivity of emissions from the two engines was apportioned by chemical compound class.

  8. Chemical composition and photochemical reactivity of exhaust from aircraft turbine engines

    Directory of Open Access Journals (Sweden)

    C. W. Spicer

    1994-08-01

    Full Text Available Assessment of the environmental impact of aircraft emissions is required by planners and policy makers. Seveal areas of concern are: 1. exposure of airport workers and urban residents to toxic chemicals emitted when the engines operate at low power (idle and taxi on the ground; 2. contributions to urban photochemical air pollution of aircraft volatile organic and nitrogen oxides emissions from operations around airports; and 3. emissions of nitrogen oxides and particles during high-altitude operation. The environmental impact of chemicals emitted from jet aircraft turbine engines has not been firmly established due to lack of data regarding emission rates and identities of the compounds emitted. This paper describes an experimental study of two different aircraft turbine engines designed to determine detailed organic emissions, as well as emissions of inorganic gases. Emissions were measured at several engine power settings. Measurements were made of detailed organic composition from C1 through C17, CO, CO2, NO, NOx, and polycyclic aromatic hydrocarbons. Measurements were made using a multi-port sampling pro be positioned directly behind the engine in the exhaust exit plane. The emission measurements have been used to determine the organic distribution by carbon number and the distribution by compound class at each engine power level. The sum of the organic species was compared with an independent measurement of total organic carbon to assess the carbon mass balance. A portion of the exhaust was captured and irradiated in outdoor smog chambers to assess the photochemical reactivity of the emissions with respect to ozone formation. The reactivity of emissions from the two engines was apportioned by chemical compound class.

  9. The conformity of BPP and vibroacoustic stimulation results in fetal non reactive non stress test

    Directory of Open Access Journals (Sweden)

    M. Modarres

    2006-08-01

    Full Text Available Background: The most frequently used test for evaluation of fetal health is the Non Stress Test (NST. Unfortunately it has a high incidence of false positive results. The combination of vibroacoustic stimulation with the NTS has been shown to reduce non reactive results. Methods: A tests assessment method was chosen with a simple randomized sampling. 40 pregnant women with non reactive NST in the first 20 minutes who received VAS in one of Tehran University's Hospitals were compared with BPP scores. A vibroacoustic stimulation was applied for a 3 seconds on the maternal abdomen and fallowed within 10 minutes.Data collection tools were NST, sonography instruments ,NST result paper, tooth brusher, watch, demographic questioner and check list. Data analysis was made by descriptive static and by using the Fisher's Exact Test (with level of significant at p<0/05. All statistical analysis were performed using an spss/win. Results: After VAS, 70% of non reactive tracing became reactive. All cases with fetal reactivity response after a VAS had a subsequent BPP score of 8 (negative predictive value of 100%. False positivity of VAS was lower than NST. Conclusion: VAS offers benefits, by decreasing the incidence of non reactive test and reducing test time. VAS lowers the rate of false positive NST. VAS is safe and allows more efficient of prenatal services. This test could be used as a rapid antepartum test to predict fetal well-being.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2009-05-15

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

  11. Military chemical warfare agent human subjects testing: part 2--long-term health effects among participants of U.S. military chemical warfare agent testing.

    Science.gov (United States)

    Brown, Mark

    2009-10-01

    Military chemical warfare agent testing from World War I to 1975 produced thousands of veterans with concerns about how their participation affected their health. A companion article describes the history of these experiments, and how the lack of clinical data hampers evaluation of long-term health consequences. Conversely, much information is available about specific agents tested and their long-term health effects in other populations, which may be invaluable for helping clinicians respond effectively to the health care and other needs of affected veterans. The following review describes tested agents and their known long-term health consequences. Although hundreds of chemicals were tested, they fall into only about a half-dozen pharmaceutical classes, including common pharmaceuticals; anticholinesterase agents including military nerve agents and pesticides; anticholinergic glycolic acid esters such as atropine; acetylcholine reactivators such as 2-PAM; psychoactive compounds including cannabinoids, phencyclidine, and LSD; and irritants including tear gas and riot control agents.

  12. The chemical reactivity of the Martian soil and implications for future missions

    Science.gov (United States)

    Zent, Aaron P.; Mckay, Christopher P.

    1994-01-01

    Possible interpretations of the results of the Viking Biology Experiments suggest that greater than 1 ppm of a thermally labile oxidant, perhaps H2O2, and about 10 ppm of a thermally stable oxidant are present in the martian soil. We reexamine these results and discuss implications for future missions, the search for organics on Mars, and the possible health and engineering effects for human exploration. We conclude that further characterization of the reactivity of the martian regolith materials is warrented-although if our present understanding is correct the oxidant does not pose a hazard to humans. There are difficulties in explaining the reactivity of the Martian soil by oxidants. Most bulk phase compounds that are capable of oxidizing H2O to O2 per the Gas Exchange Experiment (GEx) are thermally labile or unstable against reduction by atmospheric CO2. Models invoking trapped O2 or peroxynitrates (NOO2(-)) require an unlikely geologic history for the Viking Lander 2 site. Most suggested oxidants, including H2O2, are expected to decompose rapidly under martian UV. Nonetheless, we conclude that the best model for the martian soil contains oxidants produced by heterogeneous chemical reactions with a photochemically produced atmospheric oxidant. The GEx results may be due to catalytic decomposition of an unstable oxidizing material by H2O. We show that interfacial reaction sites covering less than 1% of the available soil surfaces could explain the Viking Biology Experiments results.

  13. Reactive Chemical Vapor Deposition Method as New Approach for Obtaining Electroluminescent Thin Film Materials

    Directory of Open Access Journals (Sweden)

    Valentina V. Utochnikova

    2012-01-01

    Full Text Available The new reactive chemical vapor deposition (RCVD method has been proposed for thin film deposition of luminescent nonvolatile lanthanide aromatic carboxylates. This method is based on metathesis reaction between the vapors of volatile lanthanide dipivaloylmethanate (Ln(dpm3 and carboxylic acid (HCarb orH2Carb′ and was successfully used in case of HCarb. Advantages of the method were demonstrated on example of terbium benzoate (Tb(bz3 and o-phenoxybenzoate thin films, and Tb(bz3 thin films were successfully examined in the OLED with the following structure glass/ITO/PEDOT:PSS/TPD/Tb(bz3/Ca/Al. Electroluminescence spectra of Tb(bz3 showed only typical luminescent bands, originated from transitions of the terbium ion. Method peculiarities for deposition of compounds of dibasic acids H2Carb′ are established on example of terbium and europium terephtalates and europium 2,6-naphtalenedicarboxylate.

  14. Computer tool to evaluate the cue reactivity of chemically dependent individuals.

    Science.gov (United States)

    Silva, Meire Luci da; Frère, Annie France; Oliveira, Henrique Jesus Quintino de; Martucci Neto, Helio; Scardovelli, Terigi Augusto

    2017-03-01

    Anxiety is one of the major influences on the dropout of relapse and treatment of substance abuse treatment. Chemically dependent individuals need (CDI) to be aware of their emotional state in situations of risk during their treatment. Many patients do not agree with the diagnosis of the therapist when considering them vulnerable to environmental stimuli related to drugs. This research presents a cue reactivity detection tool based on a device acquiring physiological signals connected to personal computer. Depending on the variations of the emotional state of the drug addict, alteration of the physiological signals will be detected by the computer tool (CT) which will modify the displayed virtual sets without intervention of the therapist. Developed in 3ds Max® software, the CT is composed of scenarios and objects that are in the habit of marijuana and cocaine dependent individual's daily life. The interaction with the environment is accomplished using a Human-Computer Interface (HCI) that converts incoming physiological signals indicating anxiety state into commands that change the scenes. Anxiety was characterized by the average variability from cardiac and respiratory rate of 30 volunteers submitted stress environment situations. To evaluate the effectiveness of cue reactivity a total of 50 volunteers who were marijuana, cocaine or both dependent were accompanied. Prior to CT, the results demonstrated a poor correlation between the therapists' predictions and those of the chemically dependent individuals. After exposure to the CT, there was a significant increase of 73% in awareness of the risks of relapse. We confirmed the hypothesis that the CT, controlled only by physiological signals, increases the perception of vulnerability to risk situations of individuals with dependence on marijuana, cocaine or both. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  15. Effect of chemical degradation on fluxes of reactive compounds – a study with a stochastic Lagrangian transport model

    Directory of Open Access Journals (Sweden)

    J. Rinne

    2012-06-01

    Full Text Available In the analyses of VOC fluxes measured above plant canopies, one usually assumes the flux above canopy to equal the exchange at the surface. Thus one assumes the chemical degradation to be much slower than the turbulent transport. We used a stochastic Lagrangian transport model in which the chemical degradation was described as first order decay in order to study the effect of the chemical degradation on above canopy fluxes of chemically reactive species. With the model we explored the sensitivity of the ratio of the above canopy flux to the surface emission on several parameters such as chemical lifetime of the compound, friction velocity, stability, and canopy density. Our results show that friction velocity and chemical lifetime affected the loss during transport the most. The canopy density had a significant effect if the chemically reactive compound was emitted from the forest floor. We used the results of the simulations together with oxidant data measured during HUMPPA-COPEC-2010 campaign at a Scots pine site to estimate the effect of the chemistry on fluxes of three typical biogenic VOCs, isoprene, α-pinene, and β-caryophyllene. Of these, the chemical degradation had a major effect on the fluxes of the most reactive species β-caryophyllene, while the fluxes of α-pinene were affected during nighttime. For these two compounds representing the mono- and sesquiterpenes groups, the effect of chemical degradation had also a significant diurnal cycle with the highest chemical loss at night. The different day and night time loss terms need to be accounted for, when measured fluxes of reactive compounds are used to reveal relations between primary emission and environmental parameters.

  16. Results of Section 4 Chemical Testing

    Data.gov (United States)

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

  17. Reactive hydro- end chlorocarbons in the troposphere and lower stratosphere : sources, distributions, and chemical impact

    Science.gov (United States)

    Scheeren, H. A.

    2003-09-01

    The work presented in this thesis focuses on measurements of chemical reactive C2 C7 non-methane hydrocarbons (NMHC) and C1 C2 chlorocarbons with atmospheric lifetimes of a few hours up to about a year. The group of reactive chlorocarbons includes the most abundant atmospheric species with large natural sources, which are chloromethane (CH3Cl), dichloromethane (CH2Cl2), and trichloromethane (CHCl3), and tetrachloroethylene (C2Cl4) with mainly anthropogenic sources. The NMHC and chlorocarbons are present at relatively low quantities in our atmosphere (10-12 10-9 mol mol-1 of air). Nevertheless, they play a key role in atmospheric photochemistry. For example, the oxidation of NMHC plays a dominant role in the formation of ozone in the troposphere, while the photolysis of chlorocarbons contributes to enhanced ozone depletion in the stratosphere. In spite of their important role, however, their global source and sinks budgets are still poorly understood. Hence, this study aims at improving our understanding of the sources, distribution, and chemical role of reactive NMHC and chlorocarbons in the troposphere and lower stratosphere. To meet this aim, a comprehensive data set of selected C2 C7 NMHC and chlorocarbons has been analyzed, derived from six aircraft measurement campaigns with two different jet aircrafts (the Dutch TUD/NLR Cessna Citation PH-LAB, and the German DLR Falcon) conducted between 1995 and 2001 (STREAM 1995 and 1997 and 1998, LBA-CLAIRE 1998, INDOEX 1999, MINOS 2001). The NMHC and chlorocarbons have been detected by gas-chromatography (GC-FID/ECD) in pre-concentrated whole air samples collected in stainless steel canister on-board the measurement aircrafts. The measurement locations include tropical (Maldives/Indian Ocean and Surinam), midlatitude (Western Europe and Canada) and polar regions (Lapland/northern Sweden) between the equator to about 70ºN, covering different seasons and pollution levels in the troposphere and lower stratosphere. Of

  18. Reactivity feedbacks of a material test research reactor fueled with various low enriched uranium dispersion fuels

    International Nuclear Information System (INIS)

    Muhammad, Farhan; Majid, Asad

    2009-01-01

    The reactivity feedbacks of a material test research reactor using various low enriched uranium fuels, having same uranium density were calculated. For this purpose, the original aluminide fuel (UAl x -Al) containing 4.40 gU/cm 3 of an MTR was replaced with silicide (U 3 Si-Al and U 3 Si 2 -Al) and oxide (U 3 O 8 -Al) dispersion fuels having the same uranium density as of the original fuel. Calculations were carried out to find the fuel temperature reactivity feedback, moderator temperature reactivity feedback, moderator density reactivity feedback and moderator void reactivity feedback. Nuclear reactor analysis codes including WIMS-D4 and CITATION were employed to carry out these calculations. It was observed that the magnitudes all the respective reactivity feedbacks from 38 deg. C to 50 deg. C and 100 deg. C, at the beginning of life, of all the fuels were very close to each other. The fuel temperature reactivity feedback of the U 3 O 8 -Al was about 2% more than the original UAl x -Al fuel. The magnitudes of the moderator temperature, moderator density and moderator void reactivity feedbacks of all the fuels, showed very minor variations from the original aluminide fuel.

  19. FUNDAMENTAL ENVIRONMENTAL REACTIVITY TESTING AND ANALYSIS OF THE HYDROGEN STORAGE MATERIAL 2LIBH4 MGH2

    Energy Technology Data Exchange (ETDEWEB)

    James, C.; Anton, D.; Cortes-Concepcion, J.; Brinkman, K.; Gray, J.

    2012-01-10

    While the storage of hydrogen for portable and stationary applications is regarded as critical in bringing PEM fuel cells to commercial acceptance, little is known of the environmental exposure risks posed in utilizing condensed phase chemical storage options as in complex hydrides. It is thus important to understand the effect of environmental exposure of metal hydrides in the case of accident scenarios. Simulated tests were performed following the United Nations standards to test for flammability and water reactivity in air for a destabilized lithium borohydride and magnesium hydride system in a 2 to 1 molar ratio respectively. It was determined that the mixture acted similarly to the parent, lithium borohydride, but at slower rate of reaction seen in magnesium hydride. To quantify environmental exposure kinetics, isothermal calorimetry was utilized to measure the enthalpy of reaction as a function of exposure time to dry and humid air, and liquid water. The reaction with liquid water was found to increase the heat flow significantly during exposure compared to exposure in dry or humid air environments. Calorimetric results showed the maximum normalized heat flow the fully charged material was 6 mW/mg under liquid phase hydrolysis; and 14 mW/mg for the fully discharged material also occurring under liquid phase hydrolysis conditions.

  20. Development of a QSAR for worst case estimates of acute toxicity of chemically reactive compounds

    NARCIS (Netherlands)

    Freidig, A.P.; Dekkers, S.; Verwei, M.; Zvinavashe, E.; Bessems, J.G.M.; Sandt, van de J.J.M.

    2007-01-01

    Future EU legislations enforce a fast hazard and risk assessment of thousands of existing chemicals. If conducted by means of present data requirements, this assessment will use a huge number of test animals and will be neither cost nor time effective. The purpose of the current research was to

  1. A simple in chemico method for testing skin sensitizing potential of chemicals using small endogenous molecules.

    Science.gov (United States)

    Nepal, Mahesh Raj; Shakya, Rajina; Kang, Mi Jeong; Jeong, Tae Cheon

    2018-06-01

    Among many of the validated methods for testing skin sensitization, direct peptide reactivity assay (DPRA) employs no cells or animals. Although no immune cells are involved in this assay, it reliably predicts the skin sensitization potential of a chemical in chemico. Herein, a new method was developed using endogenous small-molecular-weight compounds, cysteamine and glutathione, rather than synthetic peptides, to differentiate skin sensitizers from non-sensitizers with an accuracy as high as DPRA. The percent depletion of cysteamine and glutathione by test chemicals was measured by an HPLC equipped with a PDA detector. To detect small-size molecules, such as cysteamine and glutathione, a derivatization by 4-(4-dimethylaminophenylazo) benzenesulfonyl chloride (DABS-Cl) was employed prior to the HPLC analysis. Following test method optimization, a cut-off criterion of 7.14% depletion was applied to differentiate skin sensitizers from non-sensitizers in combination of the ratio of 1:25 for cysteamine:test chemical with 1:50 for glutathione:test chemical for the best predictivity among various single or combination conditions. Although overlapping HPLC peaks could not be fully resolved for some test chemicals, high levels of sensitivity (100.0%), specificity (81.8%), and accuracy (93.3%) were obtained for 30 chemicals tested, which were comparable or better than those achieved with DPRA. Copyright © 2018 Elsevier B.V. All rights reserved.

  2. Local and linear chemical reactivity response functions at finite temperature in density functional theory

    International Nuclear Information System (INIS)

    Franco-Pérez, Marco; Ayers, Paul W.; Gázquez, José L.; Vela, Alberto

    2015-01-01

    We explore the local and nonlocal response functions of the grand canonical potential density functional at nonzero temperature. In analogy to the zero-temperature treatment, local (e.g., the average electron density and the local softness) and nonlocal (e.g., the softness kernel) intrinsic response functions are defined as partial derivatives of the grand canonical potential with respect to its thermodynamic variables (i.e., the chemical potential of the electron reservoir and the external potential generated by the atomic nuclei). To define the local and nonlocal response functions of the electron density (e.g., the Fukui function, the linear density response function, and the dual descriptor), we differentiate with respect to the average electron number and the external potential. The well-known mathematical relationships between the intrinsic response functions and the electron-density responses are generalized to nonzero temperature, and we prove that in the zero-temperature limit, our results recover well-known identities from the density functional theory of chemical reactivity. Specific working equations and numerical results are provided for the 3-state ensemble model

  3. Optimization of integrated chemical-biological degradation of a reactive azo dye using response surface methodology

    Energy Technology Data Exchange (ETDEWEB)

    Sudarjanto, Gatut [Advanced Wastewater Management Centre, The University of Queensland, Qld 4072 (Australia); Keller-Lehmann, Beatrice [Advanced Wastewater Management Centre, The University of Queensland, Qld 4072 (Australia); Keller, Jurg [Advanced Wastewater Management Centre, The University of Queensland, Qld 4072 (Australia)]. E-mail: j.keller@awmc.uq.edu.au

    2006-11-02

    The integrated chemical-biological degradation combining advanced oxidation by UV/H{sub 2}O{sub 2} followed by aerobic biodegradation was used to degrade C.I. Reactive Azo Red 195A, commonly used in the textile industry in Australia. An experimental design based on the response surface method was applied to evaluate the interactive effects of influencing factors (UV irradiation time, initial hydrogen peroxide dosage and recirculation ratio of the system) on decolourisation efficiency and optimizing the operating conditions of the treatment process. The effects were determined by the measurement of dye concentration and soluble chemical oxygen demand (S-COD). The results showed that the dye and S-COD removal were affected by all factors individually and interactively. Maximal colour degradation performance was predicted, and experimentally validated, with no recirculation, 30 min UV irradiation and 500 mg H{sub 2}O{sub 2}/L. The model predictions for colour removal, based on a three-factor/five-level Box-Wilson central composite design and the response surface method analysis, were found to be very close to additional experimental results obtained under near optimal conditions. This demonstrates the benefits of this approach in achieving good predictions while minimising the number of experiments required.

  4. Optimization of integrated chemical-biological degradation of a reactive azo dye using response surface methodology

    International Nuclear Information System (INIS)

    Sudarjanto, Gatut; Keller-Lehmann, Beatrice; Keller, Jurg

    2006-01-01

    The integrated chemical-biological degradation combining advanced oxidation by UV/H 2 O 2 followed by aerobic biodegradation was used to degrade C.I. Reactive Azo Red 195A, commonly used in the textile industry in Australia. An experimental design based on the response surface method was applied to evaluate the interactive effects of influencing factors (UV irradiation time, initial hydrogen peroxide dosage and recirculation ratio of the system) on decolourisation efficiency and optimizing the operating conditions of the treatment process. The effects were determined by the measurement of dye concentration and soluble chemical oxygen demand (S-COD). The results showed that the dye and S-COD removal were affected by all factors individually and interactively. Maximal colour degradation performance was predicted, and experimentally validated, with no recirculation, 30 min UV irradiation and 500 mg H 2 O 2 /L. The model predictions for colour removal, based on a three-factor/five-level Box-Wilson central composite design and the response surface method analysis, were found to be very close to additional experimental results obtained under near optimal conditions. This demonstrates the benefits of this approach in achieving good predictions while minimising the number of experiments required

  5. Comparison of Electrocoagulation and Chemical Coagulation Processes in Removing Reactive red 196 from Aqueous Solution

    Directory of Open Access Journals (Sweden)

    Ali Assadi

    2016-06-01

    Full Text Available Background: Conventional chemical coagulation is considered as an old method to dye and COD removal in textile effluent. Electrocoagulation (EC process is a robust method to achieve maximum removal. Methods: This study was designed to compare the result of operational parameters including optimum pH and coagulant concentration for chemical coagulation with ferric chloride and alum also, voltage, electrolysis time, initial pH, and conductivity for EC with iron electrodes to remove reactive red 196 (RR 196. Results: The outcomes show that ferric chloride and alum at optimum concentration were capable of removing dye and COD by 79.63 % and 84.83% and 53% and 55%, respectively. In contrast, EC process removed the dye and COD by 99.98% and 90.4%, respectively. Conclusion: The highest treatment efficiency was obtained by increasing the voltage, electrolysis time, pH and conductivity. Increase initial dye concentration reduces removal efficiency. Ultimately, it could be concluded that EC technology is an efficient procedure for handling of colored industrial wastewaters.

  6. A note on the heritability of reactivity assessed at field tests for Danish Warmblood horses

    DEFF Research Database (Denmark)

    Rothmann, Janne; Christensen, Ole F.; Søndergaard, Eva

    2014-01-01

    Temperament traits in horses, especially reactivity, are an important trait in relation to human–horse accidents and the welfare of the horses. However, so far, temperament is often not included in many horse breeding programs. Most of the behavioral genetic studies in horses have been based on i......, a high standard error was untainted. Nevertheless, results suggested a genetic variation of reactivity when assessed at field tests, but further research is needed before reactivity can be incorporated as a selection criteria into a breeding program....

  7. Chemical Imaging and Dynamical Studies of Reactivity and Emergent Behavior in Complex Interfacial Systems. Final Technical Report

    Energy Technology Data Exchange (ETDEWEB)

    Sibener, Steven J. [Univ. of Chicago, IL (United States). James Franck Inst. and Dept. of Chemistry

    2014-03-11

    This research program explored the efficacy of using molecular-level manipulation, imaging and scanning tunneling spectroscopy in conjunction with supersonic molecular beam gas-surface scattering to significantly enhance our understanding of chemical processes occurring on well-characterized interfaces. One program focus was on the spatially-resolved emergent behavior of complex reaction systems as a function of the local geometry and density of adsorbate-substrate systems under reaction conditions. Another focus was on elucidating the emergent electronic and related reactivity characteristics of intentionally constructed single and multicomponent atom- and nanoparticle-based materials. We also examined emergent chirality and self-organization in adsorbed molecular systems where collective interactions between adsorbates and the supporting interface lead to spatial symmetry breaking. In many of these studies we combined the advantages of scanning tunneling (STM) and atomic force (AFM) imaging, scanning tunneling local electronic spectroscopy (STS), and reactive supersonic molecular beams to elucidate precise details of interfacial reactivity that had not been observed by more traditional surface science methods. Using these methods, it was possible to examine, for example, the differential reactivity of molecules adsorbed at different bonding sites in conjunction with how reactivity is modified by the local configuration of nearby adsorbates. At the core of this effort was the goal of significantly extending our understanding of interfacial atomic-scale interactions to create, with intent, molecular assemblies and materials with advanced chemical and physical properties. This ambitious program addressed several key topics in DOE Grand Challenge Science, including emergent chemical and physical properties in condensed phase systems, novel uses of chemical imaging, and the development of advanced reactivity concepts in combustion and catalysis including carbon

  8. Quantifying and Addressing the DOE Material Reactivity Requirements with Analysis and Testing of Hydrogen Storage Materials & Systems

    Energy Technology Data Exchange (ETDEWEB)

    Khalil, Y. F. [United Technologies Research Center (UTRC), East Hartford, CT (United States)

    2012-04-30

    The objective of this project is to examine safety aspects of candidate hydrogen storage materials and systems being developed in the DOE Hydrogen Program. As a result of this effort, the general DOE safety target will be given useful meaning by establishing a link between the characteristics of new storage materials and the satisfaction of safety criteria. This will be accomplished through the development and application of formal risk analysis methods, standardized materials testing, chemical reactivity characterization, novel risk mitigation approaches and subscale system demonstration. The project also will collaborate with other DOE and international activities in materials based hydrogen storage safety to provide a larger, highly coordinated effort.

  9. A reaction-based paradigm to model reactive chemical transport in groundwater with general kinetic and equilibrium reactions

    International Nuclear Information System (INIS)

    Zhang, Fan; Yeh, Gour-Tsyh; Parker, Jack C.; Brooks, Scott C; Pace, Molly; Kim, Young Jin; Jardine, Philip M.; Watson, David B.

    2007-01-01

    This paper presents a reaction-based water quality transport model in subsurface flow systems. Transport of chemical species with a variety of chemical and physical processes is mathematically described by M. partial differential equations (PDEs). Decomposition via Gauss-Jordan column reduction of the reaction network transforms M. species reactive transport equations into two sets of equations: a set of thermodynamic equilibrium equations representing NE equilibrium reactions and a set of reactive transport equations of M-NE kinetic-variables involving no equilibrium reactions (a kinetic-variable is a linear combination of species). The elimination of equilibrium reactions from reactive transport equations allows robust and efficient numerical integration. The model solves the PDEs of kinetic-variables rather than individual chemical species, which reduces the number of reactive transport equations and simplifies the reaction terms in the equations. A variety of numerical methods are investigated for solving the coupled transport and reaction equations. Simulation comparisons with exact solutions were performed to verify numerical accuracy and assess the effectiveness of various numerical strategies to deal with different application circumstances. Two validation examples involving simulations of uranium transport in soil columns are presented to evaluate the ability of the model to simulate reactive transport with complex reaction networks involving both kinetic and equilibrium reactions

  10. A reaction-based paradigm to model reactive chemical transport in groundwater with general kinetic and equilibrium reactions.

    Science.gov (United States)

    Zhang, Fan; Yeh, Gour-Tsyh; Parker, Jack C; Brooks, Scott C; Pace, Molly N; Kim, Young-Jin; Jardine, Philip M; Watson, David B

    2007-06-16

    This paper presents a reaction-based water quality transport model in subsurface flow systems. Transport of chemical species with a variety of chemical and physical processes is mathematically described by M partial differential equations (PDEs). Decomposition via Gauss-Jordan column reduction of the reaction network transforms M species reactive transport equations into two sets of equations: a set of thermodynamic equilibrium equations representing N(E) equilibrium reactions and a set of reactive transport equations of M-N(E) kinetic-variables involving no equilibrium reactions (a kinetic-variable is a linear combination of species). The elimination of equilibrium reactions from reactive transport equations allows robust and efficient numerical integration. The model solves the PDEs of kinetic-variables rather than individual chemical species, which reduces the number of reactive transport equations and simplifies the reaction terms in the equations. A variety of numerical methods are investigated for solving the coupled transport and reaction equations. Simulation comparisons with exact solutions were performed to verify numerical accuracy and assess the effectiveness of various numerical strategies to deal with different application circumstances. Two validation examples involving simulations of uranium transport in soil columns are presented to evaluate the ability of the model to simulate reactive transport with complex reaction networks involving both kinetic and equilibrium reactions.

  11. Evaluation of skin test reactivity to environmental allergens in healthy cats and cats with atopic dermatitis.

    Science.gov (United States)

    Schleifer, Sebastian G; Willemse, Ton

    2003-06-01

    To evaluate skin test reactivity to environmental allergens in healthy cats and in cats with atopic dermatitis (AD). 10 healthy cats and 10 cats with AD. 10 allergens in serial dilutions were injected ID on the lateral aspect of the thorax of sedated cats. Histamine (0.01% solution) and buffer solutions were used as positive and negative controls, respectively. Immediately after the last injection, 10% fluorescein solution was administered IV. Skin test results were evaluated with ultraviolet light after 15 to 30 minutes and at 4 and 6 hours by 2 independent observers. In the control group, skin tests were repeated after 6 weeks. Skin test reactivity and the nature of the immunoglobulin involved were investigated by use of the Prausnitz-Küstner test with untreated and heat-treated cat sera. Intertest and interobserver agreement were high when measurement of the diameter of the fluorescent wheal was used to evaluate skin test responses, compared with assessment of its intensity. In both groups of cats, immediate skin test reactivity was observed as an IgE-mediated reaction, as an IgG-mediated reaction, and as a result of nonspecific mast cell degranulation. There was no correlation between allergen concentration and the type of reaction observed. Skin test reactivity in cats should be evaluated after IV administration of 10% fluorescein solution by means of a Prausnitz-Küstner test to differentiate among IgE-mediated, IgG-mediated, and nonspecific reactions.

  12. Reliability performance testing of totally encapsulating chemical protective suits

    International Nuclear Information System (INIS)

    Johnson, J.S.; Swearengen, P.M.

    1991-01-01

    The need to assure a high degree of reliability for totally encapsulating chemical protective (TECP) suits has been recognized by Lawrence Livermore National Laboratory's (LLNL) Hazards Control Department for some time. The following four tests were proposed as necessary to provide complete evaluation of TECP suit performance: 1. Quantitative leak test (ASTM draft), 2. Worst-case chemical exposure test (conceptual), 3. Pressure leak-rate test (complete, ASTM F1057-87), and 4. Chemical leak-rate test (ASTM draft). This paper reports on these tests which should be applied to measuring TECP suit performance in two stages: design qualification tests and field use tests. Test 1, 2, and 3 are used as design qualification tests, and tests 3 and 4 are used as field use tests

  13. The synergistic effect of chemical carcinogens enhances Epstein-Barr virus reactivation and tumor progression of nasopharyngeal carcinoma cells.

    Science.gov (United States)

    Fang, Chih-Yeu; Huang, Sheng-Yen; Wu, Chung-Chun; Hsu, Hui-Yu; Chou, Sheng-Ping; Tsai, Ching-Hwa; Chang, Yao; Takada, Kenzo; Chen, Jen-Yang

    2012-01-01

    Seroepidemiological studies imply a correlation between Epstein-Barr virus (EBV) reactivation and the development of nasopharyngeal carcinoma (NPC). N-nitroso compounds, phorbols, and butyrates are chemicals found in food and herb samples collected from NPC high-risk areas. These chemicals have been reported to be risk factors contributing to the development of NPC, however, the underlying mechanism is not fully understood. We have demonstrated previously that low dose N-methyl-N'-nitro-N-nitrosoguanidine (MNNG, 0.1 µg/ml) had a synergistic effect with 12-O-tetradecanoylphorbol-13-acetate (TPA) and sodium butyrate (SB) in enhancing EBV reactivation and genome instability in NPC cells harboring EBV. Considering that residents in NPC high-risk areas may contact regularly with these chemical carcinogens, it is vital to elucidate the relation between chemicals and EBV and their contributions to the carcinogenesis of NPC. In this study, we constructed a cell culture model to show that genome instability, alterations of cancer hallmark gene expression, and tumorigenicity were increased after recurrent EBV reactivation in NPC cells following combined treatment of TPA/SB and MNNG. NPC cells latently infected with EBV, NA, and the corresponding EBV-negative cell, NPC-TW01, were periodically treated with MNNG, TPA/SB, or TPA/SB combined with MNNG. With chemically-induced recurrent reactivation of EBV, the degree of genome instability was significantly enhanced in NA cells treated with a combination of TPA/SB and MNNG than those treated individually. The Matrigel invasiveness, as well as the tumorigenicity in mouse, was also enhanced in NA cells after recurrent EBV reactivation. Expression profile analysis by microarray indicates that many carcinogenesis-related genes were altered after recurrent EBV reactivation, and several aberrations observed in cell lines correspond to alterations in NPC lesions. These results indicate that cooperation between chemical carcinogens can

  14. Chemical reactivation of resin-embedded pHuji adds red for simultaneous two-color imaging with EGFP

    Science.gov (United States)

    Guo, Wenyan; Liu, Xiuli; Liu, Yurong; Gang, Yadong; He, Xiaobin; Jia, Yao; Yin, Fangfang; Li, Pei; Huang, Fei; Zhou, Hongfu; Wang, Xiaojun; Gong, Hui; Luo, Qingming; Xu, Fuqiang; Zeng, Shaoqun

    2017-01-01

    The pH-sensitive fluorescent proteins enabling chemical reactivation in resin are useful tools for fluorescence microimaging. EGFP or EYFP is good for such applications. For simultaneous two-color imaging, a suitable red fluorescent protein is an urgent need. Here a pH-sensitive red fluorescent protein, pHuji, is selected and verified to remain pH-sensitive in HM20 resin. We observe 183% fluorescence intensity of pHuji in resin-embeded mouse brain and 29.08-fold fluorescence intensity of reactivated pHuji compared to the quenched state. pHuji and EGFP can be quenched and chemically reactivated simultaneously in resin, thus enabling simultaneous two-color micro-optical sectioning tomography of resin-embedded mouse brain. This method may greatly facilitate the visualization of neuronal morphology and neural circuits to promote understanding of the structure and function of the brain. PMID:28717566

  15. Investigation on reactivity of iron nickel oxides in chemical looping dry reforming

    International Nuclear Information System (INIS)

    Huang, Zhen; He, Fang; Chen, Dezhen; Zhao, Kun; Wei, Guoqiang; Zheng, Anqing; Zhao, Zengli; Li, Haibin

    2016-01-01

    Iron nickel oxides as oxygen carriers were investigated to clarify the reaction mechanism of NiFe_2O_4 material during the chemical looping dry reforming (CLDR) process. The thermodynamic analysis showed that metallic Fe can be oxidized into Fe_3O_4 by CO_2, but metallic Ni cannot. The oxidizability of the four oxygen carriers was in the order of NiO > synthetic NiFe_2O_4 spinel > NiO-Fe_2O_3 mixed oxides > Fe_2O_3, and the reducibility sequence of their reduced products was synthetic NiFe_2O_4 spinel > NiO-Fe_2O_3 mixed oxides > Fe_2O_3 > NiO. The NiO showed the best oxidizability but it was easy to cause CH_4 cracking and its reduced product (Ni) did not recover lattice oxygen under CO_2 atmosphere. It only produced 74 mL CO for 1 g Fe_2O_3 during the CO_2 reforming because of its weak oxidizability. The Redox ability of synthetic NiFe_2O_4 was obvious higher than that of NiO-Fe_2O_3 mixed oxides due to the synergistic effect of metallic Fe-Ni in the spinel structure. 1 g synthetic NiFe_2O_4 can produce 238 mL CO, which was twice higher than that of 1 g NiO-Fe_2O_3 mixed oxides (111 mL). A part of Fe element was divorced from the NiFe_2O_4 spinel structure after one cycle, which was the major reason for degradation of reactivity of NiFe_2O_4 oxygen carrier. - Highlights: • A synergistic effect of Fe/Ni can improve the reactivity of oxygen carrier (OC). • The oxidizability sequence of four OCs is NiO > NiFe_2O_4 > mixed NiO + Fe_2O_3 > Fe_2O_3. • The reducibility sequence of four OCs is NiFe_2O_4 > mixed NiO + Fe_2O_3 > Fe_2O_3 > NiO. • The formation of Fe (Ni) alloy phase facilitates more CO_2 reduced into CO. • Part of Fe is divorced from the spinel structure, leading to the degeneration of OC reactivity.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-07-11

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

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

    International Nuclear Information System (INIS)

    Hamaguchi, Satoshi

    2013-01-01

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

  18. Reactive Imprint Lithography: Combined Topographical Patterning and Chemical Surface Functionalization of Polystyrene-block-poly(tert-butyl acrylate) Films

    NARCIS (Netherlands)

    Duvigneau, Joost; Cornelissen, Stijn; Bardajı´Valls, Nuria; Schönherr, Holger; Vancso, Gyula J.

    2009-01-01

    Here, reactive imprint lithography (RIL) is introduced as a new, one-step lithographic tool for the fabrication of large-area topographically patterned, chemically activated polymer platforms. Films of polystyrene-block-poly(tert-butyl acrylate) (PS-b-PtBA) are imprinted with PDMS master stamps at

  19. Modeling the transport of chemical warfare agents and simulants in polymeric substrates for reactive decontamination

    Science.gov (United States)

    Pearl, Thomas; Mantooth, Brent; Varady, Mark; Willis, Matthew

    2014-03-01

    Chemical warfare agent simulants are often used for environmental testing in place of highly toxic agents. This work sets the foundation for modeling decontamination of absorbing polymeric materials with the focus on determining relationships between agents and simulants. The correlations of agents to simulants must consider the three way interactions in the chemical-material-decontaminant system where transport and reaction occur in polymer materials. To this end, diffusion modeling of the subsurface transport of simulants and live chemical warfare agents was conducted for various polymer systems (e.g., paint coatings) with and without reaction pathways with applied decontamination. The models utilized 1D and 2D finite difference diffusion and reaction models to simulate absorption and reaction in the polymers, and subsequent flux of the chemicals out of the polymers. Experimental data including vapor flux measurements and dynamic contact angle measurements were used to determine model input parameters. Through modeling, an understanding of the relationship of simulant to live chemical warfare agent was established, focusing on vapor emission of agents and simulants from materials.

  20. Skin prick test reactivity to aeroallergens by filaggrin mutation status

    DEFF Research Database (Denmark)

    Hougaard, M G; Johansen, J D; Linneberg, A

    2014-01-01

    BACKGROUND: Studies have shown that filaggrin gene (FLG) mutations are positively associated with sensitization to aero allergens. We hypothesized that FLG mutations would also have an effect on the mean size of positive skin prick test (SPT) reactions as well as the number of positive reactions....... OBJECTIVE: To investigate the effect of FLG mutations on the mean size and the number of positive SPT reactions, as well as the association with positive specific IgE. METHODS: A random sample of 3335 adults from the general population in Denmark was genotyped for the R501X and 2282del4 mutations in the FLG...... mutations alone are insufficient to cause secondary sensitization to allergens. The positive association seen in patients must be explained by a combination of further barrier abnormality caused by dermatitis as well as increased allergen exposure....

  1. Reactivity anomaly surveillance in the Fast Flux Test Facility through cycle 3

    International Nuclear Information System (INIS)

    Knutson, B.J.; Harris, R.A.

    1984-08-01

    The technique for monitoring core reactivity during power operation used at the Fast Flux Test Facility (FFTF) is described. This technique relies on comparing predicted to measured rod positions to detect any anomalous (or unpredicted) core reactivity changes. It is implemented on the Plant Data System (PDS) computer and thus provides rapid indication of any abnormal core conditions. The prediction algorithms use thermal-hydraulic, control rod position and neutron flux sensor information to predict the core reactivity state. Initial results of using this technique based mainly on theoretical formulations is presented. The results show that the reactivity changes due to increasing reactor power (power defect) and burnup of the fuel were within approx. 16% of predicted values. To increase the sensitivity and accuracy of this technique, the prediction algorithms were calibrated to actual operating data. The work of calibrating this technique and the results of using the calibrated technique up through the third full operating cycle are summarized

  2. 76 FR 1067 - Testing of Certain High Production Volume Chemicals; Second Group of Chemicals

    Science.gov (United States)

    2011-01-07

    ... Mfg & NOES (number based criteria based criteria significant chemicals (lbs) industrial of workers... 2070-AD16 Testing of Certain High Production Volume Chemicals; Second Group of Chemicals AGENCY... section 4(a)(1)(B) of the Toxic Substances Control Act (TSCA) to require manufacturers, importers, and...

  3. Safety in the Chemical Laboratory: Tested Disposal Methods for Chemical Wastes from Academic Laboratories.

    Science.gov (United States)

    Armour, M. A.; And Others

    1985-01-01

    Describes procedures for disposing of dichromate cleaning solution, picric acid, organic azides, oxalic acid, chemical spills, and hydroperoxides in ethers and alkenes. These methods have been tested under laboratory conditions and are specific for individual chemicals rather than for groups of chemicals. (JN)

  4. Identification of chemicals related to the chemical weapons convention during an interlaboratory proficiency test

    NARCIS (Netherlands)

    Hooijschuur, E.W.J.; Hulst, A.G.; Jong, A.L. de; Reuver, L.P. de; Krimpen, S.H. van; Baar, B.L.M. van; Wils, E.R.J.; Kientz, C.E.; Brinkman, U.A.Th

    2002-01-01

    In order to test the ability of laboratories to detect and identify chemicals related to the Chemical Weapons Convention (CWC), which prohibits the development, production, stockpiling and use of chemical weapons, and to designate laboratories for this task, the Technical Secretariat of the

  5. Long-term reactive transport modelling of stabilized/solidified waste: from dynamic leaching tests to disposal scenarios

    Energy Technology Data Exchange (ETDEWEB)

    Windt, Laurent de [Ecole des Mines de Paris, CG-Hydrodynamics and Reaction Group, 35 R. St-Honore, 77300 Fontainebleau (France)]. E-mail: laurent.dewindt@ensmp.fr; Badreddine, Rabia [INERIS, Direction des Risques Chroniques, Unite Dechets et Sites Pollues, Parc Technologique Alata BP 2, 60550 Verneuil-en-Halatte (France); Lagneau, Vincent [Ecole des Mines de Paris, CG-Hydrodynamics and Reaction Group, 35 R. St-Honore, 77300 Fontainebleau (France)

    2007-01-31

    Environmental impact assessment of hazardous waste disposal relies, among others, on standardized leaching tests characterized by a strong coupling between diffusion and chemical processes. In that respect, this study shows that reactive transport modelling is a useful tool to extrapolate laboratory results to site conditions characterized by lower solution/solid (L/S) ratios, site specific geometry, infiltration, etc. A cement solidified/stabilized (S/S) waste containing lead is investigated as a typical example. The reactive transport model developed in a previous study to simulate the initial state of the waste as well as laboratory batch and dynamic tests is first summarized. Using the same numerical code (HYTEC), this model is then integrated to a simplified waste disposal scenario assuming a defective cover and rain water infiltration. The coupled evolution of the S/S waste chemistry and the pollutant plume migration are modelled assessing the importance of the cracking state of the monolithic waste. The studied configurations correspond to an undamaged and fully sealed system, a few main fractures between undamaged monoliths and, finally, a dense crack-network in the monoliths. The model considers the potential effects of cracking, first the increase of rain water and carbon dioxide infiltration and, secondly, the increase of L/S ratio and reactive surfaces, using either explicit fracture representation or dual porosity approaches.

  6. Quick Look Report for Chemical Reactivity Modeling of Various Multi-Canister Overpack Breaches

    Energy Technology Data Exchange (ETDEWEB)

    Bratton, Robert Lawrence

    2002-04-01

    This report makes observations or shows trends in the response and does not specifically provide conclusions or predict the onset of bulk uranium oxidation safety margins based on hole size. Comprehensive analysis will be provided in the future. The report should animate discussions about the results and what should be analyzed further in the final analysis. This report intends only to show the response of the breached multi-canister overpack (MCO) as a function of event time using the GOTH_SNF computer code. The response will be limited to physical quantities available on the exterior of the MCO. The GOTH_SNF model is approximate, because not all physical phenomenon was included in the model. Error estimates in the response are not possible at this time, because errors in the actual physical data are not known. Sensitivities in the results from variations in the physical data have not been pursued at this time, either. This effort was undertaken by the National Spent Nuclear Fuel Program to evaluate potential chemical reactivity issues of a degraded uranium metal spent nuclear fuel using the MCO fully loaded with Mark IV N-reactor fuel as the evaluation model. This configuration is proposed for handling in the Yucca Mountain Project (YMP) surface facility. Hanford is loading N-reactor fuel elements into the MCO for interim storage at the Hanford site with permanent disposal proposed at YMP. A portion of the N-reactor fuel inventory has suffered corrosion, exposing the uranium metal under the zircaloy cladding. Because of the sealed MCO, the local radiation field, and decay heat of the fuel, hydrogen production cannot be ruled out from the metal hydrates on the surface of the zircaloy cladding and exposed fuel. Because of the much greater surface area, the oxyhydroxide composition, and water of hydration in the uranium metal corrosion product, the corrosion product will be a significant water source that may equal the absorbed water on the zircaloy cladding. A

  7. Quick Look Report for Chemical Reactivity Modeling of Various Multi-Canister Overpack Breaches

    International Nuclear Information System (INIS)

    Bratton, Robert Lawrence

    2002-01-01

    This report makes observations or shows trends in the response and does not specifically provide conclusions or predict the onset of bulk uranium oxidation safety margins based on hole size. Comprehensive analysis will be provided in the future. The report should animate discussions about the results and what should be analyzed further in the final analysis. This report intends only to show the response of the breached multi-canister overpack (MCO) as a function of event time using the GOTH( ) SNF computer code. The response will be limited to physical quantities available on the exterior of the MCO. The GOTH( ) SNF model is approximate, because not all physical phenomenon was included in the model. Error estimates in the response are not possible at this time, because errors in the actual physical data are not known. Sensitivities in the results from variations in the physical data have not been pursued at this time, either. This effort was undertaken by the National Spent Nuclear Fuel Program to evaluate potential chemical reactivity issues of a degraded uranium metal spent nuclear fuel using the MCO fully loaded with Mark IV N-reactor fuel as the evaluation model. This configuration is proposed for handling in the Yucca Mountain Project (YMP) surface facility. Hanford is loading N-reactor fuel elements into the MCO for interim storage at the Hanford site with permanent disposal proposed at YMP. A portion of the N-reactor fuel inventory has suffered corrosion, exposing the uranium metal under the zircaloy cladding. Because of the sealed MCO, the local radiation field, and decay heat of the fuel, hydrogen production cannot be ruled out from the metal hydrates on the surface of the zircaloy cladding and exposed fuel. Because of the much greater surface area, the oxyhydroxide composition, and water of hydration in the uranium metal corrosion product, the corrosion product will be a significant water source that may equal the absorbed water on the zircaloy cladding

  8. Atomistic-level non-equilibrium model for chemically reactive systems based on steepest-entropy-ascent quantum thermodynamics

    International Nuclear Information System (INIS)

    Li, Guanchen; Al-Abbasi, Omar; Von Spakovsky, Michael R

    2014-01-01

    This paper outlines an atomistic-level framework for modeling the non-equilibrium behavior of chemically reactive systems. The framework called steepest- entropy-ascent quantum thermodynamics (SEA-QT) is based on the paradigm of intrinsic quantum thermodynamic (IQT), which is a theory that unifies quantum mechanics and thermodynamics into a single discipline with wide applications to the study of non-equilibrium phenomena at the atomistic level. SEA-QT is a novel approach for describing the state of chemically reactive systems as well as the kinetic and dynamic features of the reaction process without any assumptions of near-equilibrium states or weak-interactions with a reservoir or bath. Entropy generation is the basis of the dissipation which takes place internal to the system and is, thus, the driving force of the chemical reaction(s). The SEA-QT non-equilibrium model is able to provide detailed information during the reaction process, providing a picture of the changes occurring in key thermodynamic properties (e.g., the instantaneous species concentrations, entropy and entropy generation, reaction coordinate, chemical affinities, reaction rate, etc). As an illustration, the SEA-QT framework is applied to an atomistic-level chemically reactive system governed by the reaction mechanism F + H 2 ↔ FH + H

  9. Le Châtelier's conjecture: Measurement of colloidal eigenstresses in chemically reactive materials

    Science.gov (United States)

    Abuhaikal, Muhannad; Ioannidou, Katerina; Petersen, Thomas; Pellenq, Roland J.-M.; Ulm, Franz-Josef

    2018-03-01

    Volume changes in chemically reactive materials, such as hydrating cement, play a critical role in many engineering applications that require precise estimates of stress and pressure developments. But a means to determine bulk volume changes in the absence of other deformation mechanisms related to thermal, pressure and load variations, is still missing. Herein, we present such a measuring devise, and a hybrid experimental-theoretical technique that permits the determination of colloidal eigenstresses. Applied to cementitious materials, it is found that bulk volume changes in saturated cement pastes at constant pressure and temperature conditions result from a competition of repulsive and attractive phenomena that originate from the relative distance of the solid particles - much as Henry Louis Le Châtelier, the father of modern cement science, had conjectured in the late 19th century. Precipitation of hydration products in confined spaces entails a repulsion, whereas the concurrent reduction in interparticle distance entails activation of attractive forces in charged colloidal particles. This cross-over from repulsion to attraction can be viewed as a phase transition between a liquid state (below the solid percolation) and the limit packing of hard spheres, separated by an energy barrier that defines the temperature-dependent eigenstress magnitude.

  10. Role of Chemical Reactivity and Transition State Modeling for Virtual Screening.

    Science.gov (United States)

    Karthikeyan, Muthukumarasamy; Vyas, Renu; Tambe, Sanjeev S; Radhamohan, Deepthi; Kulkarni, Bhaskar D

    2015-01-01

    Every drug discovery research program involves synthesis of a novel and potential drug molecule utilizing atom efficient, economical and environment friendly synthetic strategies. The current work focuses on the role of the reactivity based fingerprints of compounds as filters for virtual screening using a tool ChemScore. A reactant-like (RLS) and a product- like (PLS) score can be predicted for a given compound using the binary fingerprints derived from the numerous known organic reactions which capture the molecule-molecule interactions in the form of addition, substitution, rearrangement, elimination and isomerization reactions. The reaction fingerprints were applied to large databases in biology and chemistry, namely ChEMBL, KEGG, HMDB, DSSTox, and the Drug Bank database. A large network of 1113 synthetic reactions was constructed to visualize and ascertain the reactant product mappings in the chemical reaction space. The cumulative reaction fingerprints were computed for 4000 molecules belonging to 29 therapeutic classes of compounds, and these were found capable of discriminating between the cognition disorder related and anti-allergy compounds with reasonable accuracy of 75% and AUC 0.8. In this study, the transition state based fingerprints were also developed and used effectively for virtual screening in drug related databases. The methodology presented here provides an efficient handle for the rapid scoring of molecular libraries for virtual screening.

  11. Towards Tetraradicaloid: The Effect of Fusion Mode on Radical Character and Chemical Reactivity

    KAUST Repository

    Hu, Pan

    2015-12-30

    Open-shell singlet diradicaloids display unique electronic, non-linear optical and magnetic activity and could become novel molecular materials for organic electronics, photonics and spintronics. However, design and synthesis of diradicaloids with a significant polyradical character is a challenging task for chemists. In this article, we report our efforts toward tetraradicaloid system. A series of potential tetraradicaloids by fusion of two p-quinodimethane (p-QDM) units with naphthalene or benzene rings in different modes were synthesized. Their model compounds containing one p-QDM moiety were also prepared and compared. Their ground-state structures, physical properties and chemical reactivity were systematically investigated by various exper-imental methods such as steady-state and transient absorption, two-photon absorption, X-ray crystallographic analysis, electron spin resonance, superconducting quantum interference device and electrochemistry, assisted by density functional theory calculations. It was found that their diradical and tetraradical characters show a clear dependence on the fusion mode. Upon the introducing of more five-membered rings, the diradical characters greatly decrease. This difference can be explained by the pro-aromaticity/anti-aromaticity of the molecules as well as the intramolecular charge transfer. Our comprehensive studies provide a guideline for the design and synthesis of stable open-shell singlet polycyclic hydrocarbons with significant polyradical characters.

  12. Chemical and Molecular Descriptors for the Reactivity of Amines with CO{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Anita S.; Kitchin, John R.

    2012-10-24

    Amine-based solvents are likely to play an important role in CO{sub 2} capture applications in the future, and the identification of amines with superior performance will facilitate their use in CO{sub 2} capture. While some improvements in performance will be achieved through process modifications, modifying the CO{sub 2} capture performance of an amine also implies in part an ability to modify the reactions between the amine and CO{sub 2} through development of new functionalized amines. We present a computational study of trends in the reactions between CO{sub 2} and functionalized amines with a focus on identifying molecular descriptors that determine trends in reactivity. We examine the formation of bicarbonate and carbamate species on three classes of functionalized amines: alkylamines, alkanolamines, and fluorinated alkylamines including primary, secondary and tertiary amines in each class. These functional groups span electron-withdrawing to donating behavior, hydrogen-bonding, extent of functionalization, and proximity effects of the functional groups. Electron withdrawing groups tend to destabilize CO{sub 2} reaction products, whereas electron-donating groups tend to stabilize CO{sub 2} reaction products. Hydrogen bonding stabilizes CO{sub 2} reaction products. Electronic structure descriptors based on electronegativity were found to describe trends in the bicarbonate formation energy. A chemical correlation was observed between the carbamate formation energy and the carbamic acid formation energy. The local softness on the reacting N in the amine was found to partially explain trends carbamic acid formation energy.

  13. Towards Tetraradicaloid: The Effect of Fusion Mode on Radical Character and Chemical Reactivity

    KAUST Repository

    Hu, Pan; Lee, Sangsu; Herng, Tun Seng; Aratani, Naoki; Goncalves, Theo; Qi, Qingbiao; Shi, Xueliang; Yamada, Hiroko; Huang, Kuo-Wei; Ding, Jun; Kim, Dongho; Wu, Jishan

    2015-01-01

    Open-shell singlet diradicaloids display unique electronic, non-linear optical and magnetic activity and could become novel molecular materials for organic electronics, photonics and spintronics. However, design and synthesis of diradicaloids with a significant polyradical character is a challenging task for chemists. In this article, we report our efforts toward tetraradicaloid system. A series of potential tetraradicaloids by fusion of two p-quinodimethane (p-QDM) units with naphthalene or benzene rings in different modes were synthesized. Their model compounds containing one p-QDM moiety were also prepared and compared. Their ground-state structures, physical properties and chemical reactivity were systematically investigated by various exper-imental methods such as steady-state and transient absorption, two-photon absorption, X-ray crystallographic analysis, electron spin resonance, superconducting quantum interference device and electrochemistry, assisted by density functional theory calculations. It was found that their diradical and tetraradical characters show a clear dependence on the fusion mode. Upon the introducing of more five-membered rings, the diradical characters greatly decrease. This difference can be explained by the pro-aromaticity/anti-aromaticity of the molecules as well as the intramolecular charge transfer. Our comprehensive studies provide a guideline for the design and synthesis of stable open-shell singlet polycyclic hydrocarbons with significant polyradical characters.

  14. Simultaneous measurements of reactive scalar and velocity in a planar liquid jet with a second-order chemical reaction

    Energy Technology Data Exchange (ETDEWEB)

    Watanabe, Tomoaki; Sakai, Yasuhiko; Nagata, Kouji; Terashima, Osamu [Nagoya University, Department of Mechanical Science and Engineering, Nagoya (Japan); Kubo, Takashi [Meijo University, Faculty of Science and Technology, Nagoya (Japan)

    2012-11-15

    This paper presents a new experimental approach for simultaneous measurements of velocity and concentration in a turbulent liquid flow with a chemical reaction. For the simultaneous measurements, we developed a combined probe consisting of an I-type hot-film probe and an optical fiber probe based on the light absorption spectrometric method. In a turbulent planar liquid jet with a second-order chemical reaction (A+B{yields}R), streamwise velocity and concentrations of all reactive species are measured by the combined probe. The turbulent mass fluxes of the reactive species are estimated from the simultaneous measurements. The results show that the influence of the chemical reaction on the turbulent mass flux of the reactant species near the jet exit is different from its influence in other regions, and the turbulent mass flux of the product species has a negative value near the jet exit and a positive value in other regions. (orig.)

  15. Nano-patterning of perpendicular magnetic recording media by low-energy implantation of chemically reactive ions

    International Nuclear Information System (INIS)

    Martin-Gonzalez, M.S.; Briones, F.; Garcia-Martin, J.M.; Montserrat, J.; Vila, L.; Faini, G.; Testa, A.M.; Fiorani, D.; Rohrmann, H.

    2010-01-01

    Magnetic nano-patterning of perpendicular hard disk media with perpendicular anisotropy, but preserving disk surface planarity, is presented here. Reactive ion implantation is used to locally modify the chemical composition (hence the magnetization and magnetic anisotropy) of the Co/Pd multilayer in irradiated areas. The procedure involves low energy, chemically reactive ion irradiation through a resist mask. Among N, P and As ions, P are shown to be most adequate to obtain optimum bit density and topography flatness for industrial Co/Pd multilayer media. The effect of this ion contributes to isolate perpendicular bits by destroying both anisotropy and magnetic exchange in the irradiated areas. Low ion fluences are effective due to the stabilization of atomic displacement levels by the chemical effect of covalent impurities.

  16. Abiotic pyrite reactivity versus nitrate, selenate and selenite using chemical and electrochemical methods

    International Nuclear Information System (INIS)

    Ignatiadis, I.; Betelu, S.; Gaucher, E.; Tournassat, C.; Chainet, F.

    2010-01-01

    Document available in extended abstract form only. This work is part of ReCosy European project (www.recosy.eu), whose main objectives are the sound understanding of redox phenomena controlling the long-term release/retention of radionuclides in nuclear waste disposal and providing tools to apply the results to performance assessment/safety case. Redox is one of the main factor affecting speciation and mobility of redox-sensitive radionuclides. Thus, it is of a great importance to investigate the redox reactivity of the host radioactive waste formations, particularly when exposed to redox perturbations. Callovo-Oxfordian formation (COx), a clay rock known as an anoxic and reducing system, was selected in France as the most suitable location to store nuclear waste. Iron (II) sulfide, mostly constituted of pyrite (FeS 2 ), iron (II) carbonate, iron(II) bearing clays and organic matter are considered to account almost entirely for the total reducing capacity of the rock. We report here the redox reactivity of pyrite upon exposure to nitrate (N(V)), selenate (Se(VI)) and selenite (Se(IV)) that possibly occur in the nuclear storage. Both, chemical and electrochemical kinetic approaches were simultaneously conducted such as to (i) determine the kinetics parameters of the reactions and (ii) understand the kinetic mechanisms. In order to reach similar conditions that are encountered in the storage system, all experiments were realised in NaCl 0.1 M, near neutral pH solutions, and an abiotic glove box (O 2 less than 10 -8 M). Chemical approach has consisted to set in contact pyrite in grains with solutions containing respectively nitrate, selenate and selenite. Reactants and products chemical analyses, conducted at different contact times, allowed us to assess the kinetics of oxidant reduction. Electrochemical approach has consisted in the continuous or semi-continuous analysis of large surface pyrite electrodes immersed in solutions with or without oxidant (nitrate

  17. Theoretical study of some aspects of the nucleo-bases reactivity: definition of new theoretical tools for the study of chemical reactivity

    International Nuclear Information System (INIS)

    Labet, V.

    2009-09-01

    In this work, three kinds of nucleo-base damages were studied from a theoretical point of view with quantum chemistry methods based on the density-functional theory: the spontaneous deamination of cytosine and its derivatives, the formation of tandem lesion induced by hydroxyl radicals in anaerobic medium and the formation of pyrimidic dimers under exposition to an UV radiation. The complementary use of quantitative static methods allowing the exploration of the potential energy surface of a chemical reaction, and of 'conceptual DFT' principles, leads to information concerning the mechanisms involved and to the rationalization of the differences in the nucleo-bases reactivity towards the formation of a same kind of damage. At the same time, a reflexion was undertaken on the asynchronous concerted mechanism concept, in terms of physical meaning of the transition state, respect of the Maximum Hardness Principle, and determination of the number of primitive processes involved. Finally, a new local reactivity index was developed, relevant to understand the reactivity of a molecular system in an excited state. (author)

  18. Study of the cross-reactivity of fish allergens based on a questionnaire and blood testing.

    Science.gov (United States)

    Kobayashi, Yukihiro; Huge, Jiletu; Imamura, Shintaro; Hamada-Sato, Naoko

    2016-07-01

    Parvalbumin and collagen have been identified as cross-reactive allergens for fish allergies. Although doctors realize that various fish elicit allergies, the targets of food allergen labeling laws were only mackerels and salmons in Japan and mackerels in South Korea. This study aimed to reveal the causative species for fish allergy via questionnaires and blood tests. Questionnaire research was conducted in Japan via the internet concerning allergies for fish-allergic patients or their family members. Next, IgE reactivities and cross-reactivities of 26 fish species were analyzed using sera obtained from 16 Japanese patients who were allergic to fish parvalbumin or collagen by enzyme-linked immunosorbent assay (ELISA) and inhibition ELISA. Questionnaire research revealed that 88% patients cannot eat mackerel and salmon in addition to other fish. In addition, 85% respondents were not satisfied with the current food allergen labeling law. In ELISA analyses, we clarified that pooled serum obtained from patients with fish parvalbumin-specific allergies exhibited IgE reactivity to the extracts of most fish species, and pooled serum obtained from patients with fish collagen-specific allergies displayed IgE reactivity to the extracts of all types of fish. Inhibition ELISA experiments revealed cross-reactivities of parvalbumin or collagen to extracts from all fish tested. Most patients with fish allergies displayed allergic symptoms following the intake of various fish species. In addition, fish parvalbumin and collagen were causative factors of fish allergy and were highly cross-reactive fish panallergens. Therefore, current laws should be revised in Japan and South Korea. Copyright © 2016 Japanese Society of Allergology. Production and hosting by Elsevier B.V. All rights reserved.

  19. Production of chemically reactive radioactive ion beams through on-line separation

    International Nuclear Information System (INIS)

    Joinet, A.

    2003-10-01

    The ISOL (isotope separation on line) allows the production of secondary radioactive ion beams through spallation or fragmentation or fission reactions that take place in a thick target bombarded by a high intensity primary beam. The challenge is to increase the intensity and purity of the radioactive beam. The optimization of the system target/source requires the right choice of material for the target by taking into account the stability of the material, its reactivity and the ionization method used. The target is an essential part of the system because radioactive elements are generated in it and are released more or less quickly. Tests have been made in order to select the best fitted material for the release of S, Se, Te, Ge and Sn. Materials tested as target filling are: ZrO 2 , Nb, Ti, V,TiO 2 , CeO x , ThO 2 , C, ZrC 4 and VC). Other molecules such as: COSe, COS, SeS, COTe, GeS, SiS, SnS have been studied to ease the extraction of recoil nuclei (Se, S, Te, Ge and Sn) produced inside the target

  20. A Tracer Test to Characterize Treatment of TCE in a Permeable Reactive Barrier

    Science.gov (United States)

    A tracer test was conducted to characterize the flow of ground water surrounding a permeable reactive barrier constructed with plant mulch (a biowall) at the OU-1 site on Altus Air Force Base, Oklahoma. This biowall is intended to intercept and treat ground water contaminated by ...

  1. Chemical Identity of Interaction of Protein with Reactive Metabolite of Diosbulbin B In Vitro and In Vivo

    Directory of Open Access Journals (Sweden)

    Kai Wang

    2017-08-01

    Full Text Available Diosbulbin B (DIOB, a hepatotoxic furan-containing compound, is a primary ingredient in Dioscorea bulbifera L., a common herbal medicine. Metabolic activation is required for DIOB-induced liver injury. Protein covalent binding of an electrophilic reactive intermediate of DIOB is considered to be one of the key mechanisms of cytotoxicity. A bromine-based analytical technique was developed to characterize the chemical identity of interaction of protein with reactive intermediate of DIOB. Cysteine (Cys and lysine (Lys residues were found to react with the reactive intermediate to form three types of protein modification, including Cys adduction, Schiff’s base, and Cys/Lys crosslink. The crosslink showed time- and dose-dependence in animals given DIOB. Ketoconazole pretreatment decreased the formation of the crosslink derived from DIOB, whereas pretreatment with dexamethasone or buthionine sulfoximine increased such protein modification. These data revealed that the levels of hepatic protein adductions were proportional to the severity of hepatotoxicity of DIOB.

  2. Drop drying on surfaces determines chemical reactivity - the specific case of immobilization of oligonucleotides on microarrays

    Science.gov (United States)

    2013-01-01

    Background Drop drying is a key factor in a wide range of technical applications, including spotted microarrays. The applied nL liquid volume provides specific reaction conditions for the immobilization of probe molecules to a chemically modified surface. Results We investigated the influence of nL and μL liquid drop volumes on the process of probe immobilization and compare the results obtained to the situation in liquid solution. In our data, we observe a strong relationship between drop drying effects on immobilization and surface chemistry. In this work, we present results on the immobilization of dye labeled 20mer oligonucleotides with and without an activating 5′-aminoheptyl linker onto a 2D epoxysilane and a 3D NHS activated hydrogel surface. Conclusions Our experiments identified two basic processes determining immobilization. First, the rate of drop drying that depends on the drop volume and the ambient relative humidity. Oligonucleotides in a dried spot react unspecifically with the surface and long reaction times are needed. 3D hydrogel surfaces allow for immobilization in a liquid environment under diffusive conditions. Here, oligonucleotide immobilization is much faster and a specific reaction with the reactive linker group is observed. Second, the effect of increasing probe concentration as a result of drop drying. On a 3D hydrogel, the increasing concentration of probe molecules in nL spotting volumes accelerates immobilization dramatically. In case of μL volumes, immobilization depends on whether the drop is allowed to dry completely. At non-drying conditions, very limited immobilization is observed due to the low oligonucleotide concentration used in microarray spotting solutions. The results of our study provide a general guideline for microarray assay development. They allow for the initial definition and further optimization of reaction conditions for the immobilization of oligonucleotides and other probe molecule classes to different

  3. Lack of Correlation between Severity of Clinical Symptoms, Skin Test Reactivity, and Radioallergosorbent Test Results in Venom-Allergic Patients

    Directory of Open Access Journals (Sweden)

    Warrington RJ

    2006-06-01

    Full Text Available Abstract Purpose To retrospectively examine the relation between skin test reactivity, venom-specific immunoglobulin E (IgE antibody levels, and severity of clinical reaction in patients with insect venom allergy. Method Thirty-six patients (including 15 females who presented with a history of allergic reactions to insect stings were assessed. The mean age at the time of the reactions was 33.4 ± 15.1 years (range, 4-76 years, and patients were evaluated 43.6 ± 90 months (range, 1-300 months after the reactions. Clinical reactions were scored according to severity, from 1 (cutaneous manifestations only to 3 (anaphylaxis with shock. These scores were compared to scores for skin test reactivity (0 to 5, indicating the log increase in sensitivity from 1 μg/mL to 0.0001 μg/mL and radioallergosorbent test (RAST levels (0 to 4, indicating venom-specific IgE levels, from undetectable to >17.5 kilounits of antigen per litre [kUA/L]. Results No correlation was found between skin test reactivity (Spearman's coefficient = 0.15, p = .377 or RAST level (Spearman's coefficient = 0.32, p = .061 and the severity of reaction. Skin test and RAST scores both differed significantly from clinical severity (p p = .042. There was no correlation between skin test reactivity and time since reaction (Spearman's coefficient = 0.18, p = .294 nor between RAST and time since reaction (r = 0.1353, p = .438. Elimination of patients tested more than 12 months after their reaction still produced no correlation between skin test reactivity (p = .681 or RAST score (p = .183 and the severity of the clinical reaction. Conclusion In venom-allergic patients (in contrast to reported findings in cases of inhalant IgE-mediated allergy, there appears to be no significant correlation between the degree of skin test reactivity or levels of venom-specific IgE (determined by RAST and the severity of the clinical reaction.

  4. Melter operation results in chemical test at Rokkasho Reprocessing Plant

    International Nuclear Information System (INIS)

    Kanehira, Norio; Yoshioka, Masahiro; Muramoto, Hitoshi; Oba, Takaaki; Takahashi, Yuji

    2005-01-01

    Chemical Test of the glass melter system of the Vitrification Facility at Rokkasho Reprocessing Plant (RRP) was performed. In this test, basic performance of heating-up of the melter, melting glass, pouring glass was confirmed using simulated materials. Through these tests and operation of all modes, good results were gained, and training of operators was completed. (author)

  5. Test Marketing Exemption (TME) for New Chemical Review under TSCA

    Science.gov (United States)

    Under section 5 of TSCA, EPA established an exemption for certain chemicals that are manufactured (including imported) for test marketing. You can learn more here about the requirements of this exemption, along with the review and submission process.

  6. Coupling Chemical Kinetics and Flashes in Reactive, Thermal and Compositional Reservoir Simulation

    DEFF Research Database (Denmark)

    Kristensen, Morten Rode; Gerritsen, Margot G.; Thomsen, Per Grove

    2007-01-01

    of convergence and error test failures by more than 50% compared to direct integration without the new algorithm. To facilitate the algorithmic development we construct a virtual kinetic cell model. We use implicit one-step ESDIRK (Explicit Singly Diagonal Implicit Runge-Kutta) methods for integration...... of the kinetics. The kinetic cell model serves both as a tool for the development and testing of tailored solvers as well as a testbed for studying the interactions between chemical kinetics and phase behavior. A comparison between a Kvalue correlation based approach and a more rigorous equation of state based......Phase changes are known to cause convergence problems for integration of stiff kinetics in thermal and compositional reservoir simulations. We propose an algorithm for detection and location of phase changes based on discrete event system theory. The algorithm provides a robust way for handling...

  7. Test Operations Procedure (TOP) 08-2-197 Chemical Protection Testing of Sorbent-Based Air Purification Components (APCs)

    Science.gov (United States)

    2016-06-24

    handling and storing the chemical materials of interest. Testing facilities intending to use chemical warfare agents (CWAs) and nontraditional agents...handling, and decontamination capabilities for research, development, test, and evaluation (RDT&E) quantities of chemical agents. Chemical agent...and decontaminated IAW the test plan and all test documentation will be archived. All recoverable chemical test materials will be accounted for and

  8. Algal growth inhibition test results of 425 organic chemical substances

    DEFF Research Database (Denmark)

    Kusk, Kresten Ole; Christensen, Anne Munch; Nyholm, Niels

    2018-01-01

    The toxicity towards the algal species Pseudokirchneriella subcapitata of 425 organic chemical substances was tested in a growth inhibition test. Precautions were taken to prevent loss of the compounds from the water phase and the test system (closed test system, low biomass, shorter test duration......, silanized glass) and to keep pH constant by applying a higher alkalinity. Chemical phase distribution was modelled taking ionization, volatilisation, and adsorption to glass and biomass into consideration. If the modelled water concentration was below 90% of the nominal concentration the calculated EC...... values were corrected accordingly. The model helped to identify substances, where the calculated water concentration was too uncertain. Substances covering a wide range of physical-chemical properties and different modes of action were tested. Median effect concentrations (EC50) lower than 1000 mg/L were...

  9. Carcinogenicity tests of certain environmental and industrial chemicals

    International Nuclear Information System (INIS)

    Weisburger, E.K.; Ulland, B.M.; Nam, J.; Gart, J.J.; Weisburger, J.H.

    1981-01-01

    Fourteen chemicals of varied uses were tested for carcinogenicity by oral administration in male and female Charles River CD rats. Under the conditions of the tests, propane sultone, propylene imine, and ethylenethiourea, in addition to the positive control N-2-fluorenylacetamide, were carcinogenic. Avadex, bis(2-chloroethyl) ether, the potassium salt of bis(2-hydroxyethyl) dithiocarbamic acid, ethylene carbonate, and semicarbazide hydrochloride were not carcinogenic under the test conditions. Dithiooxamide, glycerol alpha-monochlorohydrin, and thiosemicarbazide gave somewhat ambiguous results, though administered at high enough dose levels to be toxic. An inadequate number of animals survived treatments with sodium azide, sodium bisulfide, and vinylene carbonate, or the animals may not have received sufficiently high doses of the test chemicals to provide maximum test sensitivity. However, there were no indications that these three chemicals were carcinogenic under the test conditions

  10. Out-of pile mechanical test: simulating reactivity initiated accident (RIA) of zircaloy-4 cladding tube

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Myung Ho; Kim, Jun Hwan; Choi, Byoung Kwon; Jeong, Young Hwan [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    2004-07-01

    The ejection or drop of a control rod in a reactivity initiated accident (RIA) causes a sudden increase in reactor power and in turn deposits a large amount of energy into the fuel. In a RIA, cladding tubes bear thermal expansion due to sudden reactivity and may fail from the resulting mechanical damage. Thus, RIA can be one of the safety margin reducers because the oxide on the tubes makes their thickness to support the load less as well as hydrides from the corrosion reduce the ductility of the tubes. In a RIA, the peak of reactor power from reactivity change is about 0.1m second and the temperature of the cladding tubes increases up to 1000 .deg. C in several seconds. Although it is hard to fully simulate the situation, several attempts to measure the change of mechanical properties under a RIA situation has done using a reduction coil, ring tension tests with high speed. This research was done to see the effect of oxide on the change of circumferential strength and ductility of Zircaloy-4 tubes in a RIA. The ring stretch tensile tests were performed with the strain rate of 1/sec and 0.01/s to simulate a transient of the cladding tube under a RIA. Since the test results of the ring tensile test are very sensitive to the lubricant, the tests were also carried out to select a suitable lubricant before the test of oxided specimens.

  11. Atomic-level spatial distributions of dopants on silicon surfaces: toward a microscopic understanding of surface chemical reactivity

    Science.gov (United States)

    Hamers, Robert J.; Wang, Yajun; Shan, Jun

    1996-11-01

    We have investigated the interaction of phosphine (PH 3) and diborane (B 2H 6) with the Si(001) surface using scanning tunneling microscopy, infrared spectroscopy, and ab initio molecular orbital calculations. Experiment and theory show that the formation of PSi heterodimers is energetically favorable compared with formation of PP dimers. The stability of the heterodimers arises from a large strain energy associated with formation of PP dimers. At moderate P coverages, the formation of PSi heterodimers leaves the surface with few locations where there are two adjacent reactive sites. This in turn modifies the chemical reactivity toward species such as PH 3, which require only one site to adsorb but require two adjacent sites to dissociate. Boron on Si(001) strongly segregates into localized regions of high boron concentration, separated by large regions of clean Si. This leads to a spatially-modulated chemical reactivity which during subsequent growth by chemical vapor deposition (CVD) leads to formation of a rough surface. The implications of the atomic-level spatial distribution of dopants on the rates and mechanisms of CVD growth processes are discussed.

  12. Reactivity to patch tests with nickel sulfate and fragrance mix in infants

    DEFF Research Database (Denmark)

    Jøhnke, H; Norberg, L A; Vach, W

    2004-01-01

    sulfate in 3 concentrations, 200, 66 and 22 microg/cm(2), and fragrance mix 430 microg/cm(2) were used. A likely case of nickel sensitivity was defined as a reproducible positive reaction with at least homogeneous erythema and palpable infiltration occurring at least 2x and present at both the 12 and 18......The pattern of patch test reactivity to nickel sulfate and fragrance mix was studied with respect to patch test performance, reproducibility and clinical relevance in a population of unselected infants followed prospectively from birth to 18 months of age. TRUE Testtrade mark patches with nickel...... sensitivity was found in only 1 child. No reproducible positive reaction to fragrance mix was found. The high proportion of transient patch test reactivity to nickel sulfate 200 microg/cm(2) indicates that this standard concentration used for adults cannot be applied to infants. The interpretation of a single...

  13. Heterogeneously catalyzed reactive extraction for biomass valorization into chemicals and fuels

    NARCIS (Netherlands)

    Ordomskiy, V.; Khodakov, A.Y.; Nijhuis, T.A.; Schouten, J.C.

    2015-01-01

    This paper focuses on the heterogeneously catalyzed reactive extraction and separation in reaction steps in organic and aqueous phases during the transformation of biomass derived products. Two approaches are demonstrated for decomposing and preserving routes for biomass transformation into valuable

  14. Continuous flow chemistry: a discovery tool for new chemical reactivity patterns.

    Science.gov (United States)

    Hartwig, Jan; Metternich, Jan B; Nikbin, Nikzad; Kirschning, Andreas; Ley, Steven V

    2014-06-14

    Continuous flow chemistry as a process intensification tool is well known. However, its ability to enable chemists to perform reactions which are not possible in batch is less well studied or understood. Here we present an example, where a new reactivity pattern and extended reaction scope has been achieved by transferring a reaction from batch mode to flow. This new reactivity can be explained by suppressing back mixing and precise control of temperature in a flow reactor set up.

  15. Continuous flow chemistry: a discovery tool for new chemical reactivity patterns

    OpenAIRE

    Hartwig, Jan; Metternich, Jan B.; Nikbin, Nikzad; Kirschning, Andreas; Ley, Steven V.

    2014-01-01

    Continuous flow chemistry as a process intensification tool is well known. However, its ability to enable chemists to perform reactions which are not possible in batch is less well studied or understood. Here we present an example, where a new reactivity pattern and extended reaction scope has been achieved by transferring a reaction from batch mode to flow. This new reactivity can be explained by suppressing back mixing and precise control of temperature in a flow reactor set up.

  16. 5-HTTLPR Expression Outside the Skin: An Experimental Test of the Emotional Reactivity Hypothesis in Children.

    Science.gov (United States)

    Weeland, Joyce; Slagt, Meike; Brummelman, Eddie; Matthys, Walter; de Castro, Bram Orobio; Overbeek, Geertjan

    2015-01-01

    There is increasing evidence that variation in the promoter region of the serotonin transporter gene SLC6A4 (i.e., the 5-HTTLPR polymorphism) moderates the impact of environmental stressors on child psychopathology. Emotional reactivity -the intensity of an individual's response to other's emotions- has been put forward as a possible mechanism underlying these gene-by-environment interactions (i.e., G×E). Compared to children homozygous for the L-allele (LL-genotypes), children carrying an S-allele (SS/SL-genotypes), specifically when they have been frequently exposed to negative emotions in the family environment, might be more emotionally reactive and therefore more susceptible to affective environmental stressors. However, the association between 5-HTTLPR and emotional reactivity in children has not yet been empirically tested. Therefore, the goal of this study was to test this association in a large-scale experiment. Children (N = 521, 52.5% boys, Mage = 9.72 years) were genotyped and randomly assigned to happy, angry or neutral dynamic facial expressions and vocalizations. Motor and affective emotional reactivity were assessed through children's self-reported negative and positive affect (n = 460) and facial electromyography activity (i.e., fEMG: the zygomaticus or "smile" muscle and the corrugator or "frown" muscle, n = 403). Parents reported on their negative and positive parenting behaviors. Children mimicked and experienced the emotion they were exposed to. However, neither motor reactivity nor affective reactivity to these emotions depended on children's 5-HTTLPR genotype: SS/SL-genotypes did not manifest any stronger response to emotional stimuli than LL-genotypes. This finding remained the same when taking the broader family environment into account, controlling for kinship, age, gender and genetic ancestry, and when including a tri-allelic factor. We found no evidence for an association between the 5-HTTLPR polymorphism and children's emotional

  17. Study of the cross-reactivity of fish allergens based on a questionnaire and blood testing

    OpenAIRE

    Kobayashi, Yukihiro; Huge, Jiletu; Imamura, Shintaro; Hamada-Sato, Naoko

    2016-01-01

    Background: Parvalbumin and collagen have been identified as cross-reactive allergens for fish allergies. Although doctors realize that various fish elicit allergies, the targets of food allergen labeling laws were only mackerels and salmons in Japan and mackerels in South Korea. This study aimed to reveal the causative species for fish allergy via questionnaires and blood tests. Methods: Questionnaire research was conducted in Japan via the internet concerning allergies for fish-allergic ...

  18. MP98, an innovative reactivity control system for LWR and VHTR, tests results on prototypes

    International Nuclear Information System (INIS)

    Emin, M.; Gagne, J.F.

    2005-01-01

    MP98' Reactivity Control System is now a technology tested on a real scale prototypes. Demonstrator is working at PWR real conditions (155 bars, 320 degree C), and many accidents configurations could be simulated. This paper presents the technology, describes the demonstrator design and presents some results. Mock up and demonstrator have permitted to optimize the design of MP98' devices to prepare industrialization. (authors)

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

    Science.gov (United States)

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

    2016-10-01

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

  20. How well can global chemistry models calculate the reactivity of short-lived greenhouse gases in the remote troposphere, knowing the chemical composition

    Directory of Open Access Journals (Sweden)

    M. J. Prather

    2018-05-01

    Full Text Available We develop a new protocol for merging in situ measurements with 3-D model simulations of atmospheric chemistry with the goal of integrating these data to identify the most reactive air parcels in terms of tropospheric production and loss of the greenhouse gases ozone and methane. Presupposing that we can accurately measure atmospheric composition, we examine whether models constrained by such measurements agree on the chemical budgets for ozone and methane. In applying our technique to a synthetic data stream of 14 880 parcels along 180° W, we are able to isolate the performance of the photochemical modules operating within their global chemistry-climate and chemistry-transport models, removing the effects of modules controlling tracer transport, emissions, and scavenging. Differences in reactivity across models are driven only by the chemical mechanism and the diurnal cycle of photolysis rates, which are driven in turn by temperature, water vapor, solar zenith angle, clouds, and possibly aerosols and overhead ozone, which are calculated in each model. We evaluate six global models and identify their differences and similarities in simulating the chemistry through a range of innovative diagnostics. All models agree that the more highly reactive parcels dominate the chemistry (e.g., the hottest 10 % of parcels control 25–30 % of the total reactivities, but do not fully agree on which parcels comprise the top 10 %. Distinct differences in specific features occur, including the spatial regions of maximum ozone production and methane loss, as well as in the relationship between photolysis and these reactivities. Unique, possibly aberrant, features are identified for each model, providing a benchmark for photochemical module development. Among the six models tested here, three are almost indistinguishable based on the inherent variability caused by clouds, and thus we identify four, effectively distinct, chemical models. Based on this

  1. Chemical Modeling of the Reactivity of Short-Lived Greenhouse Gases: A Model Inter-Comparison Prescribing a Well-Measured, Remote Troposphere

    Science.gov (United States)

    Prather, Michael J.; Flynn, Clare M.; Zhu, Xin; Steenrod, Stephen D.; Strode, Sarah A.; Fiore, Arlene M.; Correa, Gustavo; Murray, Lee T.; Lamarque, Jean-Francois

    2018-01-01

    We develop a new protocol for merging in situ measurements with 3-D model simulations of atmospheric chemistry with the goal of integrating over the data to identify the most reactive air parcels in terms of tropospheric production and loss of the greenhouse gases ozone and methane. Presupposing that we can accurately measure atmospheric composition, we examine whether models constrained by such measurements agree on the chemical budgets for ozone and methane. In applying our technique to a synthetic data stream of 14,880 parcels along 180W, we are able to isolate the performance of the photochemical modules operating within their global chemistry-climate and chemistry-transport models, removing the effects of modules controlling tracer transport, emissions, and scavenging. Differences in reactivity across models are driven only by the chemical mechanism and the diurnal cycle of photolysis rates, which are driven in turn by temperature, water vapor, solar zenith angle, clouds, and possibly aerosols and overhead ozone, which are calculated in each model. We evaluate six global models and identify their differences and similarities in simulating the chemistry through a range of innovative diagnostics. All models agree that the more highly reactive parcels dominate the chemistry (e.g., the hottest 10% of parcels control 25-30% of the total reactivities), but do not fully agree on which parcels comprise the top 10%. Distinct differences in specific features occur, including the regions of maximum ozone production and methane loss, as well as in the relationship between photolysis and these reactivities. Unique, possibly aberrant, features are identified for each model, providing a benchmark for photochemical module development. Among the 6 models tested here, 3 are almost indistinguishable based on the inherent variability caused by clouds, and thus we identify 4, effectively distinct, chemical models. Based on this work, we suggest that water vapor differences in

  2. How well can global chemistry models calculate the reactivity of short-lived greenhouse gases in the remote troposphere, knowing the chemical composition

    Science.gov (United States)

    Prather, Michael J.; Flynn, Clare M.; Zhu, Xin; Steenrod, Stephen D.; Strode, Sarah A.; Fiore, Arlene M.; Correa, Gustavo; Murray, Lee T.; Lamarque, Jean-Francois

    2018-05-01

    We develop a new protocol for merging in situ measurements with 3-D model simulations of atmospheric chemistry with the goal of integrating these data to identify the most reactive air parcels in terms of tropospheric production and loss of the greenhouse gases ozone and methane. Presupposing that we can accurately measure atmospheric composition, we examine whether models constrained by such measurements agree on the chemical budgets for ozone and methane. In applying our technique to a synthetic data stream of 14 880 parcels along 180° W, we are able to isolate the performance of the photochemical modules operating within their global chemistry-climate and chemistry-transport models, removing the effects of modules controlling tracer transport, emissions, and scavenging. Differences in reactivity across models are driven only by the chemical mechanism and the diurnal cycle of photolysis rates, which are driven in turn by temperature, water vapor, solar zenith angle, clouds, and possibly aerosols and overhead ozone, which are calculated in each model. We evaluate six global models and identify their differences and similarities in simulating the chemistry through a range of innovative diagnostics. All models agree that the more highly reactive parcels dominate the chemistry (e.g., the hottest 10 % of parcels control 25-30 % of the total reactivities), but do not fully agree on which parcels comprise the top 10 %. Distinct differences in specific features occur, including the spatial regions of maximum ozone production and methane loss, as well as in the relationship between photolysis and these reactivities. Unique, possibly aberrant, features are identified for each model, providing a benchmark for photochemical module development. Among the six models tested here, three are almost indistinguishable based on the inherent variability caused by clouds, and thus we identify four, effectively distinct, chemical models. Based on this work, we suggest that water vapor

  3. Chemical Protection Testing of Sorbent-Based Air Purification Components (APCs)

    Science.gov (United States)

    2016-06-24

    handling and storing the chemical materials of interest. Testing facilities intending to use chemical warfare agents (CWAs) and nontraditional agents...handling, and decontamination capabilities for research, development, test, and evaluation (RDT&E) quantities of chemical agents. Chemical agent...and decontaminated IAW the test plan and all test documentation will be archived. All recoverable chemical test materials will be accounted for and

  4. Core dynamics analysis for reactivity insertion and loss of coolant flow tests using the HTTR

    International Nuclear Information System (INIS)

    Takamatsu, Kuniyoshi; Nakagawa, Shigeaki; Takeda, Tetsuaki

    2007-01-01

    The High Temperature engineering Test Reactor (HTTR) is a graphite-moderated and a gas-cooled reactor with a thermal power of 30 MW and a reactor outlet coolant temperature of 950degC (SAITO, 1994). Safety demonstration tests using the HTTR are in progress to verify its inherent safety features and improve the safety technology and design methodology for High-Temperature Gas-cooled Reactors (HTGRs) (TACHIBANA 2002) (NAKAGAWA 2004). The reactivity insertion test is one of the safety demonstration tests for the HTTR. This test simulates the rapid increase in the reactor power by withdrawing the control rod without operating the reactor power control system. In addition, the loss of coolant flow tests has been conducted to simulate the rapid decrease in the reactor power by tripping one, two or all out of three gas circulators. The experimental results have revealed the inherent safety features of HTGRs, such as the negative reactivity feedback effect. The numerical analysis code, which was named ACCORD (TAKAMATSU 2006), was developed to analyze the reactor dynamics including the flow behavior in the HTTR core. We used a conventional method, namely, a one-dimensional flow channel model and reactor kinetics model with a single temperature coefficient, taking into account the temperature changes in the core. However, a slight difference between the analytical and experimental results was observed. Therefore, we have modified this code to use a model with four parallel channels and twenty temperature coefficients in the core. Furthermore, we added another analytical model of the core for calculating the heat conduction between the fuel channels and the core in the case of the loss of coolant flow tests. This paper describes the validation results for the newly developed code using the experimental results of the reactivity insertion test as well as the loss of coolant flow tests by tripping one or two out of three gas circulators. Finally, the pre-analytical result of

  5. OECD Guidelines for the Testing of Chemicals, Test No. 232: Collembolan Reproduction Test in Soil

    DEFF Research Database (Denmark)

    Krogh, Paul Henning; Scott-Fordsmand, Janeck James; Ahtianen, Jukka

    2009-01-01

    This Test Guideline is designed for assessing the effects of chemicals on the reproduction of collembolans in soil. The parthenogenetic Folsomia candida is the recommended species for use, but an alternative species such as sexually reproducing Folsomia fimetaria could also be used if they meet...... the validity criteria. This Guideline can be used for testing both water soluble and insoluble substances but it is not applicable to volatile ones. The Guideline aims to determine toxic effects of the test substance on adult mortality and reproductive output expressed as LCx and ECx respectively, or NOEC....../LOEC value. The number of treatment concentrations varies depending on endpoints to be determined. For a combined approach to examine both the NOEC/LOEC and ECx, eight concentrations in a geometric series with four replicates for each concentration as well as eight control replicates should be used. In each...

  6. Simulations of the dispersion of reactive pollutants in a street canyon, considering different chemical mechanisms and micromixing

    Science.gov (United States)

    Garmory, A.; Kim, I. S.; Britter, R. E.; Mastorakos, E.

    The Stochastic Fields (SF) or Field Monte Carlo method has been used to model the dispersion of reactive scalars in a street canyon, using a simple chemistry and the CBM-IV mechanism. SF is a Probability Density Function (PDF) method which allows both means and variances of the scalars to be calculated as well as considering the effect of segregation on reaction rates. It was found that the variance of reactive scalars such as NO 2 was very high in the mixing region at roof-top level with rms values of the order of the mean values. The effect of segregation on major species such as O 3 was found to be very small using either mechanism, however, some radical species in CBM-IV showed a significant difference. These were found to be the seven species with the fastest chemical timescales. The calculated photostationary state defect was also found to be in error when segregation is neglected.

  7. A comparative study of changes in immunological reactivity during prolonged introduction of radioactive and chemical substances into the organism with drinking water

    International Nuclear Information System (INIS)

    Shubik, V.M.; Nevstrueva, M.A.; Kalnitskij, S.A.; Livshits, R.E.; Merkushev, G.N.; Pilshchik, E.M.; Ponomareva, T.V.

    1978-01-01

    A comparative study was conducted into the factors of non-specific protection and specific immunity, allergic and autoallergic reactivities during prolonged exposure of experimental animals to 6 different radioactive and 7 harmful chemical substances. Qualitative and quantitative peculiarities were found in the changes in immunological reactivity during the exposure of the organism to radionuclides and stable chemical compounds. Impairment of immunity plays an essential role in the course and the outcome of effects induced by chronic action of the substances examined. (author)

  8. 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.

  9. A Simple Visualization of Double Bond Properties: Chemical Reactivity and UV Fluorescence

    Science.gov (United States)

    Grayson, Scott M.

    2012-01-01

    A simple, easily visualized thin-layer chromatography (TLC) staining experiment is presented that highlights the difference in reactivity between aromatic double bonds and nonaromatic double bonds. Although the stability of aromatic systems is a major theme in organic chemistry, the concept is rarely reinforced "visually" in the undergraduate…

  10. [Non-animal toxicology in the safety testing of chemicals].

    Science.gov (United States)

    Heinonen, Tuula; Tähti, Hanna

    2013-01-01

    There is an urgent need to develop predictive test methods better than animal experiments for assessing the safety of chemical substances to man. According to today's vision this is achieved by using human cell based tissue and organ models. In the new testing strategy the toxic effects are assessed by the changes in the critical parameters of the cellular biochemical routes (AOP, adverse toxic outcome pathway-principle) in the target tissues. In vitro-tests are rapid and effective, and with them automation can be applied. The change in the testing paradigm is supported by all stakeholders: scientists, regulators and people concerned on animal welfare.

  11. A theory for bioinorganic chemical reactivity of oxometal complexes and analogous oxidants: the exchange and orbital-selection rules.

    Science.gov (United States)

    Usharani, Dandamudi; Janardanan, Deepa; Li, Chunsen; Shaik, Sason

    2013-02-19

    Over the past decades metalloenzymes and their synthetic models have emerged as an area of increasing research interest. The metalloenzymes and their synthetic models oxidize organic molecules using oxometal complexes (OMCs), especially oxoiron(IV)-based ones. Theoretical studies have helped researchers to characterize the active species and to resolve mechanistic issues. This activity has generated massive amounts of data on the relationship between the reactivity of OMCs and the transition metal's identity, oxidation state, ligand sphere, and spin state. Theoretical studies have also produced information on transition state (TS) structures, reaction intermediates, barriers, and rate-equilibrium relationships. For example, the experimental-theoretical interplay has revealed that nonheme enzymes carry out H-abstraction from strong C-H bonds using high-spin (S = 2) oxoiron(IV) species with four unpaired electrons on the iron center. However, other reagents with higher spin states and more unpaired electrons on the metal are not as reactive. Still other reagents carry out these transformations using lower spin states with fewer unpaired electrons on the metal. The TS structures for these reactions exhibit structural selectivity depending on the reactive spin states. The barriers and thermodynamic driving forces of the reactions also depend on the spin state. H-Abstraction is preferred over the thermodynamically more favorable concerted insertion into C-H bonds. Currently, there is no unified theoretical framework that explains the totality of these fascinating trends. This Account aims to unify this rich chemistry and understand the role of unpaired electrons on chemical reactivity. We show that during an oxidative step the d-orbital block of the transition metal is enriched by one electron through proton-coupled electron transfer (PCET). That single electron elicits variable exchange interactions on the metal, which in turn depend critically on the number of

  12. Chemical reactivity of {alpha}-isosaccharinic acid in heterogeneous alkaline systems

    Energy Technology Data Exchange (ETDEWEB)

    Glaus, M. A.; Loon, L. R. Van

    2009-05-15

    Cellulose degradation under alkaline conditions is of relevance for the mobility of many radionuclides in the near-field of a cementitious repository for radioactive waste, because metal-binding degradation products may be formed. Among these, {alpha}- isosaccharinic acid ({alpha}-ISA) is the strongest complexant. The prediction of the equilibrium concentration of {alpha}-ISA in cement pore water is therefore an important step in the assessment of the influence of cellulose degradation products on the speciation of radionuclides in such environments. The present report focuses on possible chemical transformation reactions of {alpha}-ISA in heterogeneous alkaline model systems containing either Ca(OH){sub 2} or crushed hardened cement paste. The transformation reactions were monitored by measuring the concentration of {alpha}-ISA by high performance anion exchange chromatography and the formation of reaction products by high performance ion exclusion chromatography. The overall loss of organic species from solution was monitored by measuring the concentration of non-purgeable organic carbon. The reactions were examined in diluted and compacted suspensions, at either 25 {sup o}C or 90 {sup o}C, and under anaerobic atmospheres obtained by various methods. It was found that {alpha}-ISA was transformed under all conditions tested to some extent. Reaction products, such as glycolate, formate, lactate and acetate, all compounds with less complexing strength than {alpha}-ISA, were detected. The amount of reaction products identified by the chromatographic technique applied was {approx} 50 % of the amount of {alpha}-ISA reacted. Sorption of {alpha}-ISA to Ca(OH){sub 2} contributed only to a minor extent to the loss of {alpha}-ISA from the solution phase. As the most important conclusion of the present work it was demonstrated that the presence of oxidising agents had a distinctive influence on the turnover of {alpha}-ISA. Under aerobic conditions {alpha}-ISA was

  13. Chemical reactivity of α-isosaccharinic acid in heterogeneous alkaline systems

    International Nuclear Information System (INIS)

    Glaus, M. A.; Loon, L. R. Van

    2008-11-01

    Cellulose degradation under alkaline conditions is of relevance for the mobility of many radionuclides in the near-field of a cementitious repository for radioactive waste, because metal-binding degradation products may be formed. Among these, α-isosaccharinic acid (α-ISA) is the strongest complexant. The prediction of the equilibrium concentration of α-ISA in cement pore water is therefore an important step in the assessment of the influence of cellulose degradation products on the speciation of radionuclides in such environments. The present report focuses on possible chemical transformation reactions of α-ISA in heterogeneous alkaline model systems containing either Ca(OH) 2 or crushed hardened cement paste. The transformation reactions were monitored by measuring the concentration of α-ISA by high performance anion exchange chromatography and the formation of reaction products by high performance ion exclusion chromatography. The overall loss of organic species from solution was monitored by measuring the concentration of non-purgeable organic carbon. The reactions were examined in diluted and compacted suspensions, either at 25 o C or 90 o C, and under anaerobic atmospheres obtained by various methods. It was found that α-ISA was transformed under all conditions tested to some extent. Reaction products, such as glycolate, formate, lactate and acetate, all compounds with less complexing strength than α-ISA, were detected. The amount of reaction products identified by the chromatographic technique applied was ∼50 % of the amount of α-ISA reacted. Sorption of α-ISA to Ca(OH) 2 contributed only to a minor extent to the loss of α-ISA from the solution phase. As the most important conclusion of the present work it was demonstrated that the presence of oxidising agents had a distinctive influence on the turnover of α-ISA. Under aerobic conditions α-ISA was quantitatively converted to reaction products, whereas under strict anaerobic conditions, only

  14. Chemical reactivity of α-isosaccharinic acid in heterogeneous alkaline systems

    International Nuclear Information System (INIS)

    Glaus, M. A.; Loon, L. R. Van

    2009-05-01

    Cellulose degradation under alkaline conditions is of relevance for the mobility of many radionuclides in the near-field of a cementitious repository for radioactive waste, because metal-binding degradation products may be formed. Among these, α- isosaccharinic acid (α-ISA) is the strongest complexant. The prediction of the equilibrium concentration of α-ISA in cement pore water is therefore an important step in the assessment of the influence of cellulose degradation products on the speciation of radionuclides in such environments. The present report focuses on possible chemical transformation reactions of α-ISA in heterogeneous alkaline model systems containing either Ca(OH) 2 or crushed hardened cement paste. The transformation reactions were monitored by measuring the concentration of α-ISA by high performance anion exchange chromatography and the formation of reaction products by high performance ion exclusion chromatography. The overall loss of organic species from solution was monitored by measuring the concentration of non-purgeable organic carbon. The reactions were examined in diluted and compacted suspensions, at either 25 o C or 90 o C, and under anaerobic atmospheres obtained by various methods. It was found that α-ISA was transformed under all conditions tested to some extent. Reaction products, such as glycolate, formate, lactate and acetate, all compounds with less complexing strength than α-ISA, were detected. The amount of reaction products identified by the chromatographic technique applied was ∼ 50 % of the amount of α-ISA reacted. Sorption of α-ISA to Ca(OH) 2 contributed only to a minor extent to the loss of α-ISA from the solution phase. As the most important conclusion of the present work it was demonstrated that the presence of oxidising agents had a distinctive influence on the turnover of α-ISA. Under aerobic conditions α-ISA was quantitatively converted to reaction products, whereas under strict anaerobic conditions, only

  15. Engineered Barrier System Thermal-Hydraulic-Chemical Column Test Report

    International Nuclear Information System (INIS)

    W.E. Lowry

    2001-01-01

    The Engineered Barrier System (EBS) Thermal-Hydraulic-Chemical (THC) Column Tests provide data needed for model validation. The EBS Degradation, Flow, and Transport Process Modeling Report (PMR) will be based on supporting models for in-drift THC coupled processes, and the in-drift physical and chemical environment. These models describe the complex chemical interaction of EBS materials, including granular materials, with the thermal and hydrologic conditions that will be present in the repository emplacement drifts. Of particular interest are the coupled processes that result in mineral and salt dissolution/precipitation in the EBS environment. Test data are needed for thermal, hydrologic, and geochemical model validation and to support selection of introduced materials (CRWMS M and O 1999c). These column tests evaluated granular crushed tuff as potential invert ballast or backfill material, under accelerated thermal and hydrologic environments. The objectives of the THC column testing are to: (1) Characterize THC coupled processes that could affect performance of EBS components, particularly the magnitude of permeability reduction (increases or decreases), the nature of minerals produced, and chemical fractionation (i.e., concentrative separation of salts and minerals due to boiling-point elevation). (2) Generate data for validating THC predictive models that will support the EBS Degradation, Flow, and Transport PMR, Rev. 01

  16. Interpretation of Chemical Pathology Test Results in Paediatrics ...

    African Journals Online (AJOL)

    At any time we interprete paediatric chemical pathology test results we must take into consideration a number of factors, which are related with and restricted to paediatric patients. Such factors include the paediatric patient's age that may change from prematurity to above 18 years, and the paediatric patient's body weight ...

  17. Out-of-pile test of zirconium cladding simulating reactivity initiated accident

    Energy Technology Data Exchange (ETDEWEB)

    Kim, J. H.; Lee, M. H.; Choi, B. K.; Bang, J. K.; Jung, Y. H. [KAERI, Taejon (Korea, Republic of)

    2004-07-01

    Mechanical properties of zirconium cladding such as Zircaloy-4 and advanced cladding were evaluated by ring tension test to simulate Reactivity-Initiated Accident (RIA) as an out-pile test. Cladding was hydrided by means of charging hydrogen up to 1000ppm to simulate high-burnup situation, finally fabricated to circumferential tensile specimen. Ring tension test was carried out from 0.01 to 1/sec to keep pace with actual RIA event. The results showed that mechanical strength of zirconium cladding increased at the value of 7.8% but ductility decreased at the 34% as applied strain rate and absorbed hydrogen increased. Further activities regarding out-of-pile testing plans for simulated high-burnup cladding were discussed in this paper.

  18. Experimental data report for Test TS-2 reactivity initiated accident test in NSRR with pre-irradiated BWR fuel rod

    International Nuclear Information System (INIS)

    Nakamura, Takehiko; Yoshinaga, Makio; Sobajima, Makoto; Fujishiro, Toshio; Kobayashi, Shinsho; Yamahara, Takeshi; Sukegawa, Tomohide; Kikuchi, Teruo

    1993-02-01

    This report presents experimental data for Test TS-2 which was the second test in a series of Reactivity Initiated Accident (RIA) condition test using pre-irradiated BWR fuel rods, performed at the Nuclear Safety Research Reactor (NSRR) in February, 1990. Test fuel rod used in the Test TS-2 was a short sized BWR (7x7) type rod which was fabricated from a commercial rod irradiated at Tsuruga Unit 1 power reactor. The fuel had an initial enrichment of 2.79% and a burnup of 21.3Gwd/tU (bundle average). A pulse irradiation of the test fuel rod was performed under a cooling condition of stagnant water at atmospheric pressure and at ambient temperature which simulated a BWR's cold start-up RIA event. The energy deposition of the fuel rod in this test was evaluated to be 72±5cal/g·fuel (66±5cal/g·fuel in peak fuel enthalpy) and no fuel failure was observed. Descriptions on test conditions, test procedures, transient behavior of the test rod during the pulse irradiation, and, results of pre and post pulse irradiation examinations are described in this report. (author)

  19. Chemical conjugation of cowpea mosaic viruses with reactive HPMA-based polymers

    Czech Academy of Sciences Publication Activity Database

    Laga, Richard; Koňák, Čestmír; Šubr, Vladimír; Ulbrich, Karel; Suthiwangcharoen, N.; Niu, Q.; Wang, Q.

    2010-01-01

    Roč. 21, č. 12 (2010), s. 1669-1685 ISSN 0920-5063 R&D Projects: GA AV ČR KJB400500803; GA ČR GA202/09/2078; GA AV ČR KAN200200651 Institutional research plan: CEZ:AV0Z40500505 Keywords : acylthiazolidine-2-thione reactive groups * bioconjugation * coating Subject RIV: CD - Macromolecular Chemistry Impact factor: 1.842, year: 2010

  20. JOYO MK-III performance test. Criticality test, excess reactivity measurement and burn-up coefficient measurement

    International Nuclear Information System (INIS)

    Maeda, Shigetaka; Sekine, Takashi; Kitano, Akihiro; Nagasaki, Hideaki

    2005-03-01

    The MK-III performance test began in June 2003 to fully characterize the upgraded core and heat transfer system of the experimental fast reactor JOYO. This paper describes the results of the approach to criticality, the excess reactivity evaluation and the burn-up coefficient measurement. In the approach to criticality test, the MK-III core achieved initial criticality at the control rod bank position of 412.8 mm on 14:03 July 2nd, 2003. Because the replacement of the outer two rows of reflector subassemblies with shielding subassemblies reduced the source range monitor signals by a factor of 3 at the same reactor power compared with those in the MK-II core, we measured the change of the monitor's response and determined the count rate 2x10 4 cps.' as an appropriate value judging the zero power criticality. In the excess reactivity evaluation, the zero power excess reactivity at 250degC was 2.99±0.10%Δk/kk' based on the measured critical rod bank position and the measured control rod worths. The predicted value by the JOYO core management code system HESTIA was 3.13±0.16%Δk/kk', showing good agreement with the measured value. The measured excess reactivity was within the safety requirement limit. In the burn-up coefficient measurement, the excess reactivity change versus the reactor burn-up was evaluated. The measurement method adopted was to measure the control rod positions during the rated power operation. A value of -2.12x10 -4 Δk/kk'/MWd was obtained as a measured burn-up coefficient. The value calculated by HESTIA was -2.12x10 -4 Δk/kk'/MWd, and it agreed well with the measured value. All technical safety requirements for MK-III core were satisfied and the calculation accuracy of the core management code system HESTIA was confirmed. (author)

  1. Acoustic sensors for the control of liquid-solid interface evolution and chemical reactivity

    International Nuclear Information System (INIS)

    Ferrandis, J.Y.; Tingry, S.; Attal, J.; Seta, P.

    2006-01-01

    Less classical than far-field acoustic investigations of solid materials and/or solid-liquid interfaces, near-field acoustic properties of an acoustic solid wave guide (tip), thin enough at its termination to present an external diameter smaller than the excitation acoustic wave wavelength, is shown to be able to probe interface properties. As a result of that, these near-field acoustic probes can play the role of chemical sensors, if chemical modifications or chemical reactions are concerned at their surface. In that context, a chemical sensor was realized by electrochemical deposition of an electron-conducting polymer (polypyrrole-biotin) on a metal tip, followed by enzyme attachment by molecular recognition process involving the biotin-avidin-specific interaction. Results from near-field acoustic showed that the enzyme modification of the polymer layer can be detected by this new acoustic sensor

  2. Experimental data report for Test TS-1 Reactivity Initiated Accident Test in NSRR with pre-irradiated BWR fuel rod

    International Nuclear Information System (INIS)

    Nakamura, Takehiko; Yoshinaga, Makio; Sobajima, Makoto; Fujishiro, Toshio; Horiki, Ohichiro; Yamahara, Takeshi; Ichihashi, Yoshinori; Kikuchi, Teruo

    1992-01-01

    This report presents experimental data for Test TS-1 which was the first in a series of tests, simulating Reactivity Initiated Accident (RIA) conditions using pre-irradiated BWR fuel rods, performed in the Nuclear Safety Research Reactor (NSRR) in October, 1989. Test fuel rod used in the Test TS-1 was a short-sized BWR (7 x 7) type rod which was fabricated from a commercial rod provided from Tsuruga Unit 1 power reactor. The fuel had an initial enrichment of 2.79 % and burnup of 21.3 GWd/t (bundle average). Pulse irradiation was performed at a condition of stagnant water cooling, atmospheric pressure and ambient temperature using a newly developed double container-type capsule. Energy deposition of the rod in this test was evaluated to be about 61 cal/g·fuel (55 cal/g·fuel in peak fuel enthalpy) and no fuel failure was observed. Descriptions on test conditions, test procedures, fuel burnup measurements, transient behavior of the test rod during pulse irradiation and results of post pulse irradiation examinations are contained in this report. (author)

  3. The mystery of gold's chemical activity: local bonding, morphology and reactivity of atomic oxygen.

    Science.gov (United States)

    Baker, Thomas A; Liu, Xiaoying; Friend, Cynthia M

    2011-01-07

    Recently, gold has been intensely studied as a catalyst for key synthetic reactions. Gold is an attractive catalyst because, surprisingly, it is highly active and very selective for partial oxidation processes suggesting promise for energy-efficient "green" chemistry. The underlying origin of the high activity of Au is a controversial subject since metallic gold is commonly thought to be inert. Herein, we establish that one origin of the high activity for gold catalysis is the extremely reactive nature of atomic oxygen bound in 3-fold coordination sites on metallic gold. This is the predominant form of O at low concentrations on the surface, which is a strong indication that it is most relevant to catalytic conditions. Atomic oxygen bound to metallic Au in 3-fold sites has high activity for CO oxidation, oxidation of olefins, and oxidative transformations of alcohols and amines. Among the factors identified as important in Au-O interaction are the morphology of the surface, the local binding site of oxygen, and the degree of order of the oxygen overlayer. In this Perspective, we present an overview of both theory and experiments that identify the reactive forms of O and their associated charge density distributions and bond strengths. We also analyze and model the release of Au atoms induced by O binding to the surface. This rough surface also has the potential for O(2) dissociation, which is a critical step if Au is to be activated catalytically. We further show the strong parallels between product distributions and reactivity for O-covered Au at low pressure (ultrahigh vacuum) and for nanoporous Au catalysts operating at atmospheric pressure as evidence that atomic O is the active species under working catalytic conditions when metallic Au is present. We briefly discuss the possible contributions of oxidants that may contain intact O-O bonds and of the Au-metal oxide support interface in Au catalysis. Finally, the challenges and future directions for fully

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

    Science.gov (United States)

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

    2013-11-01

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

  5. Topological analysis (BCP) of vibrational spectroscopic studies, docking, RDG, DSSC, Fukui functions and chemical reactivity of 2-methylphenylacetic acid

    Science.gov (United States)

    Kavimani, M.; Balachandran, V.; Narayana, B.; Vanasundari, K.; Revathi, B.

    2018-02-01

    Experimental FT-IR and FT-Raman spectra of 2-methylphenylacetic acid (MPA) were recorded and theoretical values are also analyzed. The non-linear optical (NLO) properties were evaluated by determination of first (5.5053 × 10- 30 e.s.u.) and second hyper-polarizabilities (7.6833 × 10- 36 e.s.u.) of the title compound. The Multiwfn package is used to find the weak non-covalent interaction (Van der Wall interaction) and strong repulsion (steric effect) of the molecule and examined by reduced density gradient. The molecular electrostatic potential (MEP) analysis used to find the most reactive sites for the electrophilic and nucleophilic attack. The chemical activity (electronegativity, hardness, chemical softness and chemical potential) of the title compound was predicted with the help of HOMO-LUMO energy values. The natural bond orbital (NBO) has been analyzed the stability of the molecule arising from the hyper-conjugative interaction. DSSCs were discussed in structural modifications that improve the electron injection efficiency of the title compound (MPA). The Fukui functions are calculated in order to get information associated with the local reactivity properties of the title compound. The binding sites of the two receptors were reported by molecular docking field and active site bond distance is same 1.9 Å. The inhibitor of the title compound forms a stable complex with 1QYV and 2H1K proteins at the binding energies are - 5.38 and - 5.85 (Δ G in kcal/mol).

  6. Reactivity Initiated Accident Test Series: Test RIA 1-2. Quick look report

    International Nuclear Information System (INIS)

    Martinson, Z.R.; Semken, R.S.; Smith, R.H.; Osetek, D.J.

    1978-12-01

    The primary objectives of Test RIA 1-2 were to (a) characterize the response of preirradiated fuel rods during an RIA event conducted at boiling water reactor (BWR) hot-startup conditions for an axial peak pellet surface energy of 200 cal/g UO 2 , and (b) evaluate the effect of internal rod pressure on preirradiated fuel rod response during an RIA event. The test consisted of four, individually shrouded, pressurized water reactor-type fuel rods previously irradiated to burnups of about 4800 MWd/t. In addition to the power calibration and preconditioning, the fuel rods were subjected to a single power burst that deposited a total pellet surface energy of approximately 200 cal/gm UO 2 at the axial peak power location (estimated using the core power chambers to relate steady state and transient powers). The test data indicate that the two irradiated fuel rods prepressurized to 2.41 MPa did not fail. FRAP-T4 calculations had predicted that prompt cladding rupture would occur for pellet surface energy depositions of 206 cal/g or greater. Although the two fuel rods prepressurized to 2.41 MPa did not fail, the data indicate that at least one of the two fuel rods prepressurized to 0.1 MPa did fail. Based on the core power chamber data, this rod failure indicates a threshold for the preirradiated fuel rods near or below 200 cal/g UO 2 total pellet surface energy at the axial flux peak

  7. Treatment of liquid effluents from uranium analytical method 'DAVIES & GRAY' by electrodialysis and electrodialysis reactive tests

    International Nuclear Information System (INIS)

    Zuniga Alvear, Karina Andrea

    2014-01-01

    This work describes the process which produces liquid waste coming from the chemical analysis laboratory of the Chilean Nuclear Energy Commission (CCHEN), from the analytical technique called 'Davies and Gray' and their further treatment, using electro dialysis (ED) and reactive electro dialysis (RED), in order to achieve lower uranium contents in solution. The contamination in water is a big problem, since there are many places in the world where is limited. For these reasons new treatments must be done, and the ion-selective membrane has opened a new path for these processes. The radioactive liquid waste have lots of other restrictions in their final disposal, which difficult even more the water recovery, because the law has very strict security margins with respect to these ones. In the case of liquid waste containing uranium, the concern increases, because being the uranium a radioactive element has it has to be lowered at its maximum, or eliminated directly, in order to avoid any kind of contamination. There exist national regulations and international recommendations. They have stipulated the correct management and disposal for radioactive waste. These can come from any uranium production process. In any of these, the liquid waste contains certain uranium content, which after the end of the process; the discarded waste must go through a conditioning and cleaning process for its afterward liberation or recycling. In this study, it was tested the electro dialysis as a radioactive waste treatment, only uranium containing waste coming from the chemical analysis laboratory in CCHEN. The electro dialysis process has a direct competition with other separation process, such as distillation, ionic exchange, and reverse osmosis, among others. The classic electro dialysis has been developed during the 50's, and until today, there has been different version, as inverse, reactive, reversible. The unidirectional and reactive electro dialysis will be the

  8. Postprandial Reactive Hypoglycaemia: Varying Presentation Patterns on Extended Glucose Tolerance Tests and Possible Therapeutic Approaches

    Directory of Open Access Journals (Sweden)

    Kevin Stuart

    2013-01-01

    Full Text Available Reactive hypoglycemia is a state characterised by sympathetic or neuroglycopenic symptoms associated with hypoglycaemia in the postprandial state resulting in considerable distress to the patient. It is our practice to carry out either extended glucose tolerance tests (eGTTs or mixed meal tests in these patients. We describe two patients who experienced hypoglycaemic symptoms early and late during eGTT. The patient who experienced symptoms early, in contrast to the patient who presented with late symptoms, did not possess any characteristics of the metabolic syndrome. Based on clinical symptoms, glucose, insulin, and free fatty acid (FFA levels, we speculate on possible mechanisms that may have accounted for each of their presentation patterns. We then discuss low glycaemic index diet which will be the mainstay of management.

  9. Typical parameters of the plasma chemical similarity in non-isothermal reactive plasmas

    International Nuclear Information System (INIS)

    Gundermann, S.; Jacobs, H.; Miethke, F.; Rutsher, A.; Wagner, H.E.

    1996-01-01

    The substance of physical similarity principles is contained in parameters which govern the comparison of different realizations of a model device. Because similarity parameters for non-isothermal plasma chemical reactors are unknown to a great extent, an analysis of relevant equations is given together with some experimental results. Modelling of the reactor and experimental results for the ozone synthesis are presented

  10. Electrochemical and Quantum Chemical Study of Reactivity of Orthophthalaldehyde with Aliphatic Primary Amines

    Czech Academy of Sciences Publication Activity Database

    Donkeng Dazie, Joel; Liška, Alan; Ludvík, Jiří

    2016-01-01

    Roč. 163, č. 9 (2016), G127-G132 ISSN 0013-4651 R&D Projects: GA ČR GA13-21704S Institutional support: RVO:61388955 Keywords : electrochemistry * quantum chemical study * amines Subject RIV: CG - Electrochemistry Impact factor: 3.259, year: 2016

  11. Surface area and chemical reactivity characteristics of uranium metal corrosion products.

    Energy Technology Data Exchange (ETDEWEB)

    Totemeier, T. C.

    1998-02-17

    The results of an initial characterization of hydride-containing corrosion products from uranium metal Zero Power Physics Reactor (ZPPR) fuel plates are presented. Sorption analyses using the BET method with a Kr adsorbate were performed to measure the specific areas of corrosion product samples. The specific surface areas of the corrosion products varied from 0.66 to 1.01 m{sup 2}/g. The reactivity of the products in Ar-9%O{sub 2} and Ar-20%O{sub 2} were measured at temperatures between 35 C and 150 C using a thermo-gravimetric analyzer. Ignition of the products occurred at temperatures of 150 C and above. The oxidation rates below ignition were comparable to rates observed for uranium metal.

  12. Quantum mechanical reactive scattering theory for simple chemical reactions: Recent developments in methodology and applications

    International Nuclear Information System (INIS)

    Miller, W.H.

    1989-08-01

    It has recently been discovered that the S-matrix version of the Kohn variational principle is free of the ''Kohn anomalies'' that have plagued other versions and prevented its general use. This has made a major contribution to heavy particle reactive (and also to electron-atom/molecule) scattering which involve non-local (i.e., exchange) interactions that prevent solution of the coupled channel equations by propagation methods. This paper reviews the methodology briefly and presents a sample of integral and differential cross sections that have been obtained for the H + H 2 → H 2 +H and D + H 2 → HD + H reactions in the high energy region (up to 1.2 eV translational energy) relevant to resonance structures reported in recent experiments. 35 refs., 11 figs

  13. Surface area and chemical reactivity characteristics of uranium metal corrosion products

    International Nuclear Information System (INIS)

    Totemeier, T. C.

    1998-01-01

    The results of an initial characterization of hydride-containing corrosion products from uranium metal Zero Power Physics Reactor (ZPPR) fuel plates are presented. Sorption analyses using the BET method with a Kr adsorbate were performed to measure the specific areas of corrosion product samples. The specific surface areas of the corrosion products varied from 0.66 to 1.01 m 2 /g. The reactivity of the products in Ar-9%O 2 and Ar-20%O 2 were measured at temperatures between 35 C and 150 C using a thermo-gravimetric analyzer. Ignition of the products occurred at temperatures of 150 C and above. The oxidation rates below ignition were comparable to rates observed for uranium metal

  14. Chemical reactivity of hydrogen, nitrogen, and oxygen atoms at temperatures below 100 k

    Science.gov (United States)

    Mcgee, H. A., Jr.

    1973-01-01

    The synthesis of unusual compounds by techniques employing cryogenic cooling to retard their very extreme reactivity was investigated. Examples of such species that were studied are diimide (N2H2), cyclobutadiene (C4H4), cyclopropanone (C3H4O), oxirene (C2H2O), and many others. Special purpose cryogenically cooled inlet arrangements were designed such that the analyses incurred no warm-up of the cold, and frequently explosively unstable, compounds. Controlled energy electron impact techniques were used to measure critical potentials and to develop the molecular energetics and thermodynamics of these molecules and to gain some insight into their kinetic characteristics as well. Three and four carbon strained ring molecules were studied. Several reactions of oxygen and hydrogen atoms with simple molecules of H, N, C, and O in hard quench configurations were studied. And the quench stabilization of BH3 was explored as a model system in cryochemistry.

  15. Attempts to identify a control system for chemical reactivity in the living state using virtual energy.

    Science.gov (United States)

    Reid, B L; Bourke, C

    2001-07-01

    This thesis explores the activation of chemicals in metabolic systems from the viewpoint that this activation is under the control of elements of the space-sea in which the chemicals are immersed. Themselves inert, the chemicals are theorised to exploit a force or action issuing from space (fluctuation) and characterized by the homogeneity (termed symmetry) of this medium. The fluctuation is heterogenized upon collision with matter from the intervention of well recognized fields of gravity and electromagnetism at the instant of its issue to form the near field of radiation. Fractions of original space waves and of their intrinsic spin are produced resulting in the activation of the orbitals (valency) in the chemical itself. The thesis continues: the disturbed fluctuation must return to space, obliging in turn, a prior return to the homogeneous state requiring special restorative wave rearrangements known as resonance. The success of the restorative resonance is signalled by a singularity of the fluctuation now propelled to infinity (space), and the contingent chemical reactions thereby terminated. Compromise to this return can occur from many causes and, in its presence, activation of the orbitals continues. They now effectively constitute autonomous reactions alienated from the system as a whole. The thesis is supported from evidence from diverse fields such as space theory, history of quantum field theory in attempts to derive its meaning, dielectrics and the near field of electromagnetic radiation, electron-space interactions at the Fermi surface during phase transitions and evolution of equilibrium conditions in resonance phenomena. The utility of the hypothesis rests on recognition of the resonance condition at various points in the system sufficiently macroscopic as to be available clinically as an abrupt interface between physiology and pathology. Copyright 2001 Harcourt Publishers Ltd.

  16. Role of Extracellular Polymeric Substances in the Surface Chemical Reactivity of Hymenobacter aerophilus, a Psychrotolerant Bacterium▿

    Science.gov (United States)

    Baker, M. G.; Lalonde, S. V.; Konhauser, K. O.; Foght, J. M.

    2010-01-01

    Bacterial surface layers, such as extracellular polymeric substances (EPS), are known to play an important role in metal sorption and biomineralization; however, there have been very few studies investigating how environmentally induced changes in EPS production affect the cell's surface chemistry and reactivity. Acid-base titrations, cadmium adsorption assays, and Fourier transform infrared spectroscopy (FT-IR) were used to characterize the surface reactivities of Hymenobacter aerophilus cells with intact EPS (WC) or stripped of EPS (SC) and purified EPS alone. Linear programming modeling of titration data showed SC to possess functional groups corresponding to phosphoryl (pKa ∼6.5), phosphoryl/amine (pKa ∼7.9), and amine/hydroxyl (pKa ∼9.9). EPS and WC both possess carboxyl groups (pKa ∼5.1 to 5.8) in addition to phosphoryl and amine groups. FT-IR confirmed the presence of polysaccharides and protein in purified EPS that can account for the additional carboxyl groups. An increased ligand density was observed for WC relative to that for SC, leading to an increase in the amount of Cd adsorbed (0.53 to 1.73 mmol/liter per g [dry weight] and 0.53 to 0.59 mmol/liter per g [dry weight], respectively). Overall, the presence of EPS corresponds to an increase in the number and type of functional groups on the surface of H. aerophilus that is reflected by increased metal adsorption relative to that for EPS-free cells. PMID:19915039

  17. Role of extracellular polymeric substances in the surface chemical reactivity of Hymenobacter aerophilus, a psychrotolerant bacterium.

    Science.gov (United States)

    Baker, M G; Lalonde, S V; Konhauser, K O; Foght, J M

    2010-01-01

    Bacterial surface layers, such as extracellular polymeric substances (EPS), are known to play an important role in metal sorption and biomineralization; however, there have been very few studies investigating how environmentally induced changes in EPS production affect the cell's surface chemistry and reactivity. Acid-base titrations, cadmium adsorption assays, and Fourier transform infrared spectroscopy (FT-IR) were used to characterize the surface reactivities of Hymenobacter aerophilus cells with intact EPS (WC) or stripped of EPS (SC) and purified EPS alone. Linear programming modeling of titration data showed SC to possess functional groups corresponding to phosphoryl (pKa approximately 6.5), phosphoryl/amine (pKa approximately 7.9), and amine/hydroxyl (pKa approximately 9.9). EPS and WC both possess carboxyl groups (pKa approximately 5.1 to 5.8) in addition to phosphoryl and amine groups. FT-IR confirmed the presence of polysaccharides and protein in purified EPS that can account for the additional carboxyl groups. An increased ligand density was observed for WC relative to that for SC, leading to an increase in the amount of Cd adsorbed (0.53 to 1.73 mmol/liter per g [dry weight] and 0.53 to 0.59 mmol/liter per g [dry weight], respectively). Overall, the presence of EPS corresponds to an increase in the number and type of functional groups on the surface of H. aerophilus that is reflected by increased metal adsorption relative to that for EPS-free cells.

  18. Temperature buffer test. Hydro-mechanical and chemical/ mineralogical characterizations

    International Nuclear Information System (INIS)

    Aakesson, Mattias; Olsson, Siv; Dueck, Ann; Nilsson, Ulf; Karnland, Ola; Kiviranta, Leena; Kumpulainen, Sirpa; Linden, Johan

    2012-01-01

    The Temperature Buffer Test (TBT) is a joint project between SKB/ANDRA and supported by ENRESA (modeling) and DBE (instrumentation), which aims at improving the understanding and to model the thermo-hydro-mechanical behavior of buffers made of swelling clay submitted to high temperatures (over 100 deg C) during the water saturation process. The test has been carried out in a KBS-3 deposition hole at Aspo HRL. It was installed during the spring of 2003. Two steel heaters (3 m long, 0.6 m diameter) and two buffer arrangements have been investigated: the lower heater was surrounded by rings of compacted Wyoming bentonite only, whereas the upper heater was surrounded by a composite barrier, with a sand shield between the heater and the bentonite. The test was dismantled and sampled during the winter of 2009/2010. This report presents the hydro-mechanical and chemical/mineralogical characterization program which was launched subsequent to the dismantling operation. The main goal has been to investigate if any significant differences could be observed between material from the field experiment and the reference material. The field samples were mainly taken from Ring 4 (located at the mid-section around the lower heater), in which the temperature in the innermost part reached 155 deg C. The following hydro-mechanical properties have been determined for the material (test technique within brackets): hydraulic conductivity (swelling pressure device), swelling pressure (swelling pressure device), unconfined compression strength (mechanical press), shear strength (triaxial cell) and retention properties (jar method). The following chemical/mineralogical properties (methods within brackets) were determined: anion analysis of water leachates (IC), chemical composition (ICP/AES+MS, EGA), cation exchange capacity (CEC, Cu-trien method) and exchangeable cations (exchange with NH4, ICPAES), mineralogical composition (XRD and FTIR), element distribution and microstructure (SEM and

  19. Thermal-mechanical-chemical responses of polymer-bonded explosives using a mesoscopic reactive model under impact loading.

    Science.gov (United States)

    Wang, XinJie; Wu, YanQing; Huang, FengLei

    2017-01-05

    A mesoscopic framework is developed to quantify the thermal-mechanical-chemical responses of polymer-bonded explosive (PBX) samples under impact loading. A mesoscopic reactive model is developed for the cyclotetramethylenetetranitramine (HMX) crystal, which incorporates nonlinear elasticity, crystal plasticity, and temperature-dependent chemical reaction. The proposed model was implemented in the finite element code ABAQUS by the user subroutine VUMAT. A series of three-dimensional mesoscale models were constructed and calculated under low-strength impact loading scenarios from 100m/s to 600m/s where only the first wave transit is studied. Crystal anisotropy and microstructural heterogeneity are responsible for the nonuniform stress field and fluctuations of the stress wave front. At a critical impact velocity (≥300m/s), a chemical reaction is triggered because the temperature contributed by the volumetric and plastic works is sufficiently high. Physical quantities, including stress, temperature, and extent of reaction, are homogenized from those across the microstructure at the mesoscale to compare with macroscale measurements, which will advance the continuum-level models. The framework presented in this study has important implications in understanding hot spot ignition processes and improving predictive capabilities in energetic materials. Copyright © 2016 Elsevier B.V. All rights reserved.

  20. Double stratification effects in chemically reactive squeezed Sutterby fluid flow with thermal radiation and mixed convection

    Science.gov (United States)

    Ahmad, S.; Farooq, M.; Javed, M.; Anjum, Aisha

    2018-03-01

    A current analysis is carried out to study theoretically the mixed convection characteristics in squeezing flow of Sutterby fluid in squeezed channel. The constitutive equation of Sutterby model is utilized to characterize the rheology of squeezing phenomenon. Flow characteristics are explored with dual stratification. In flowing fluid which contains heat and mass transport, the first order chemical reaction and radiative heat flux affect the transport phenomenon. The systems of non-linear governing equations have been modulating which then solved by mean of convergent approach (Homotopy Analysis Method). The graphs are reported and illustrated for emerging parameters. Through graphical explanations, drag force, rate of heat and mass transport are conversed for different pertinent parameters. It is found that heat and mass transport rate decays with dominant double stratified parameters and chemical reaction parameter. The present two-dimensional examination is applicable in some of the engineering processes and industrial fluid mechanics.

  1. Quasi-equilibria and plasma chemical similarity in non-isothermal reactive plasmas

    International Nuclear Information System (INIS)

    Miethke, F.; Rutscher, A.; Wagner, H.E.

    2000-01-01

    With regard to the output of stable products the mode of operation of non-isothermal plasma chemical reactors shows physical and chemical well defined states, which represent limiting cases and may be interpreted as quasi-equilibrium states. The occurrence and the characteristics of these states, meanwhile more than once observed and described, are demonstrated by an instructive model reaction. Within the frame of the so-called Macroscopic Kinetics a central parameter is dominating the reactor operation. This result may be generalized and is linked up to the application of similarity principles for the reactor operation. After the general formulation of such principles, starting from the balance equations of particles and energy, a dimensionless similarity parameter is formulated, characterizing the composition of the effluent gas of the reactor. The applicability of this parameter is demonstrated by experimental examples. (Authors)

  2. Integrated testing strategies can be optimal for chemical risk classification.

    Science.gov (United States)

    Raseta, Marko; Pitchford, Jon; Cussens, James; Doe, John

    2017-08-01

    There is an urgent need to refine strategies for testing the safety of chemical compounds. This need arises both from the financial and ethical costs of animal tests, but also from the opportunities presented by new in-vitro and in-silico alternatives. Here we explore the mathematical theory underpinning the formulation of optimal testing strategies in toxicology. We show how the costs and imprecisions of the various tests, and the variability in exposures and responses of individuals, can be assembled rationally to form a Markov Decision Problem. We compute the corresponding optimal policies using well developed theory based on Dynamic Programming, thereby identifying and overcoming some methodological and logical inconsistencies which may exist in the current toxicological testing. By illustrating our methods for two simple but readily generalisable examples we show how so-called integrated testing strategies, where information of different precisions from different sources is combined and where different initial test outcomes lead to different sets of future tests, can arise naturally as optimal policies. Copyright © 2017 Elsevier Inc. All rights reserved.

  3. Application of a Virtual Reactivity Feedback Control Loop in Non-Nuclear Testing of a Fast Spectrum Reactor

    International Nuclear Information System (INIS)

    Bragg-Sitton, Shannon M.; Forsbacka, Matthew

    2004-01-01

    For a compact, fast-spectrum reactor, reactivity feedback is dominated by core deformation at elevated temperature. Given the use of accurate deformation measurement techniques, it is possible to simulate nuclear feedback in non-nuclear electrically heated reactor tests. Implementation of simulated reactivity feedback in response to measured deflection is being tested at the Nasa Marshall Space Flight Center Early Flight Fission Test Facility (EFF-TF). During tests of the SAFE-100 reactor prototype, core deflection was monitored using a high resolution camera. 'Virtual' reactivity feedback was accomplished by applying the results of Monte Carlo calculations (MCNPX) to core deflection measurements; the computational analysis was used to establish the reactivity worth of various core deformations. The power delivered to the SAFE-100 prototype was then adjusted accordingly via kinetics calculations. The work presented in this paper will demonstrate virtual reactivity feedback as core power was increased from 1 kWt to 10 kWt, held approximately constant at 10 kWt, and then allowed to decrease based on the negative thermal reactivity coefficient. (authors)

  4. Double stratification effects in chemically reactive squeezed Sutterby fluid flow with thermal radiation and mixed convection

    Directory of Open Access Journals (Sweden)

    S. Ahmad

    2018-03-01

    Full Text Available A current analysis is carried out to study theoretically the mixed convection characteristics in squeezing flow of Sutterby fluid in squeezed channel. The constitutive equation of Sutterby model is utilized to characterize the rheology of squeezing phenomenon. Flow characteristics are explored with dual stratification. In flowing fluid which contains heat and mass transport, the first order chemical reaction and radiative heat flux affect the transport phenomenon. The systems of non-linear governing equations have been modulating which then solved by mean of convergent approach (Homotopy Analysis Method. The graphs are reported and illustrated for emerging parameters. Through graphical explanations, drag force, rate of heat and mass transport are conversed for different pertinent parameters. It is found that heat and mass transport rate decays with dominant double stratified parameters and chemical reaction parameter. The present two-dimensional examination is applicable in some of the engineering processes and industrial fluid mechanics. Keywords: Squeezing flow, Sutterby fluid model, Mixed convection, Double stratification, Thermal radiation, Chemical reaction

  5. Differential skin test reactivity to pollens in pollen food allergy syndrome versus allergic rhinitis.

    Science.gov (United States)

    Ta, Von; Scott, David R; Chin, William K; Wineinger, Nathan E; Kelso, John M; White, Andrew A

    2015-01-01

    Pollen food allergy syndrome (PFAS), also called oral allergy syndrome, is a form of food allergy in which uncooked foods cause allergic symptoms generally limited to the oral mucosa. It occurs in a subset of patients with pollen allergy, although not all patients have prominent rhinitis symptoms. PFAS is related to antigenic similarity between the pollen and food allergen. The size of skin test reactions in a group of subjects with pollen sensitivity with PFAS was compared with a group of subjects who were pollen sensitive and without PFAS. Self-reported rhinitis symptoms between the two groups were compared to identify if symptom severity differed. Twenty subjects with PFAS and 20 subjects with seasonal allergic rhinitis without PFAS were enrolled in the study. All the subjects underwent standard skin-prick testing to a panel of common allergens, including select fresh fruits and vegetables. The subjects completed a Mini Rhinoconjunctivitis Quality of Life Questionnaire as part of their clinical evaluation. The subjects with PFAS and those without PFAS were compared statistically. The subjects with PFAS had significantly larger-sized skin-prick test results specific to pollens (p PFAS reported milder nasal symptoms in relation to pollen skin test result size when compared with allergic rhinitis controls without PFAS. Our study outlined basic differences between two seemingly similar patient groups with a particularly striking discordance between skin test result sizes and rhinitis symptoms. This discordance should be explored further to increase mechanistic understanding of allergen cross-reactivity in PFAS.

  6. Laboratory tests in support of the MSRE reactive gas removal system

    International Nuclear Information System (INIS)

    Rudolph, J.C.; Del Cul, G.D.; Caja, J.; Toth, L.M.; Williams, D.F.; Thomas, K.S.; Clark, D.E.

    1997-07-01

    The Molten Salt Reactor Experiment (MSRE) at Oak Ridge National Laboratory has been shut down since December 1969, at which time the molten salt mixture of LiF-BeF 2 -ZrF 4 - 233 UF 4 (64.5-30.3-5.0-0.13 mol%) was transferred to fuel salt drain tanks for storage. In the late 1980s, increased radiation in one of the gas lines from the drain tank was attributed to 233 UF 6 . In 1994 two gas samples were withdraw (from a gas line in the Vent House connecting to the drain tanks) and analyzed. Surprisingly, 350 mm Hg of F 2 , 70 mm Hg of UF 6 , and smaller amounts of other gases were found in both of the samples. To remote this gas from above the drain tanks and all of the associated piping, the reactive gas removal system (RGRS) was designed. This report details the laboratory testing of the RGRS, using natural uranium, prior to its implementation at the MSRE facility. The testing was performed to ensure that the equipment functioned properly and was sufficient to perform the task while minimizing exposure to personnel. In addition, the laboratory work provided the research and development effort necessary to maximize the performance of the system. Throughout this work technicians and staff who were to be involved in RGRS operation at the MSRE site worked directly with the research staff in completing the laboratory testing phase. Consequently, at the end of the laboratory work, the personnel who were to be involved in the actual operations had acquired all of the training and experience necessary to continue with the process of reactive gas removal

  7. Opisthorchis felineus negatively associates with skin test reactivity in Russia-EuroPrevall-International Cooperation study.

    Science.gov (United States)

    Fedorova, O S; Janse, J J; Ogorodova, L M; Fedotova, M M; Achterberg, R A; Verweij, J J; Fernández-Rivas, M; Versteeg, S A; Potts, J; Minelli, C; van Ree, R; Burney, P; Yazdanbakhsh, M

    2017-07-01

    Most studies on the relationship between helminth infections and atopic disorders have been conducted in (sub)tropical developing countries where exposure to multiple parasites and lifestyle can confound the relationship. We aimed to study the relationship between infection with the fish-borne helminth Opishorchis felineus and specific IgE, skin prick testing, and atopic symptoms in Western Siberia, with lifestyle and hygiene standards of a developed country. Schoolchildren aged 7-11 years were sampled from one urban and two rural regions. Skin prick tests (SPT) and specific IgE (sIgE) against food and aeroallergens were measured, and data on allergic symptoms and on demographic and socioeconomic factors were collected by questionnaire. Diagnosis of opisthorchiasis was based on PCR performed on stool samples. Of the 732 children included, 34.9% had opisthorchiasis. The sensitization to any allergen when estimated by positive SPT was 12.8%, while much higher, 24.0%, when measured by sIgE. Atopic symptoms in the past year (flexural eczema and/or rhinoconjunctivitis) were reported in 12.4% of the children. SPT was positively related to flexural eczema and rhinoconjunctivitis, but not to wheezing. Opisthorchiasis showed association with lower SPT response, as well as borderline association with low IgE reactivity to any allergen. However, the effect of opisthorchiasis on SPT response was not mediated by IgE, suggesting that opisthorchiasis influences SPT response through another mechanism. Opisthorchiasis also showed borderline association with lower atopic symptoms. There is a negative association between a chronic helminth infection and skin prick test reactivity even in a developed country. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  8. Octazethrene and Its Isomer with Different Diradical Characters and Chemical Reactivity: The Role of the Bridge Structure

    KAUST Repository

    Hu, Pan

    2016-03-11

    The fundamental relationship between structure and diradical character is important for the development of open-shell diradicaloid-based materials. In this work, we synthesized two structural isomers bearing a 2,6-naphthoquinodimethane or a 1,5-naphthoquinodimethane bridge and demonstrated that their diradical characters and chemical reactivity are quite different. The mesityl or pentafluorophenyl substituted octazethrene derivatives OZ-M/OZ-F and their isomer OZI-M (with mesityl substituents) were synthesized via an intramolecular Friedel-Crafts alkylation followed by oxidative dehydrogenation strategy from the key building blocks 4 and 11. Our detailed experimental and theoretical studies showed that both isomers have an open-shell singlet ground state with a remarkable diradical character (y0 = 0.35 and 0.34 for OZ-M and OZ-F, and y0 = 0.58 for OZI-M). Compounds OZ-M and OZ-F have good stability under the ambient environment while OZI-M has high reactivity and can be easily oxidized to a dioxo-product 15, which can be correlated to their different diradical characters. Additionally, we investigated the physical properties of OZ-M, OZ-F and 15.

  9. A Model to Couple Flow, Thermal and Reactive Chemical Transport, and Geo-mechanics in Variably Saturated Media

    Science.gov (United States)

    Yeh, G. T.; Tsai, C. H.

    2015-12-01

    This paper presents the development of a THMC (thermal-hydrology-mechanics-chemistry) process model in variably saturated media. The governing equations for variably saturated flow and reactive chemical transport are obtained based on the mass conservation principle of species transport supplemented with Darcy's law, constraint of species concentration, equation of states, and constitutive law of K-S-P (Conductivity-Degree of Saturation-Capillary Pressure). The thermal transport equation is obtained based on the conservation of energy. The geo-mechanic displacement is obtained based on the assumption of equilibrium. Conventionally, these equations have been implicitly coupled via the calculations of secondary variables based on primary variables. The mechanisms of coupling have not been obvious. In this paper, governing equations are explicitly coupled for all primary variables. The coupling is accomplished via the storage coefficients, transporting velocities, and conduction-dispersion-diffusion coefficient tensor; one set each for every primary variable. With this new system of equations, the coupling mechanisms become clear. Physical interpretations of every term in the coupled equations will be discussed. Examples will be employed to demonstrate the intuition and superiority of these explicit coupling approaches. Keywords: Variably Saturated Flow, Thermal Transport, Geo-mechanics, Reactive Transport.

  10. Octazethrene and Its Isomer with Different Diradical Characters and Chemical Reactivity: The Role of the Bridge Structure

    KAUST Repository

    Hu, Pan; Lee, Sangsu; Park, Kyu Hyung; Das, Soumyajit; Herng, Tun Seng; Goncalves, Theo; Huang, Kuo-Wei; Ding, Jun; Kim, Dongho; Wu, Jishan

    2016-01-01

    The fundamental relationship between structure and diradical character is important for the development of open-shell diradicaloid-based materials. In this work, we synthesized two structural isomers bearing a 2,6-naphthoquinodimethane or a 1,5-naphthoquinodimethane bridge and demonstrated that their diradical characters and chemical reactivity are quite different. The mesityl or pentafluorophenyl substituted octazethrene derivatives OZ-M/OZ-F and their isomer OZI-M (with mesityl substituents) were synthesized via an intramolecular Friedel-Crafts alkylation followed by oxidative dehydrogenation strategy from the key building blocks 4 and 11. Our detailed experimental and theoretical studies showed that both isomers have an open-shell singlet ground state with a remarkable diradical character (y0 = 0.35 and 0.34 for OZ-M and OZ-F, and y0 = 0.58 for OZI-M). Compounds OZ-M and OZ-F have good stability under the ambient environment while OZI-M has high reactivity and can be easily oxidized to a dioxo-product 15, which can be correlated to their different diradical characters. Additionally, we investigated the physical properties of OZ-M, OZ-F and 15.

  11. Prediction of the Chapman-Jouguet chemical equilibrium state in a detonation wave from first principles based reactive molecular dynamics.

    Science.gov (United States)

    Guo, Dezhou; Zybin, Sergey V; An, Qi; Goddard, William A; Huang, Fenglei

    2016-01-21

    The combustion or detonation of reacting materials at high temperature and pressure can be characterized by the Chapman-Jouguet (CJ) state that describes the chemical equilibrium of the products at the end of the reaction zone of the detonation wave for sustained detonation. This provides the critical properties and product kinetics for input to macroscale continuum simulations of energetic materials. We propose the ReaxFF Reactive Dynamics to CJ point protocol (Rx2CJ) for predicting the CJ state parameters, providing the means to predict the performance of new materials prior to synthesis and characterization, allowing the simulation based design to be done in silico. Our Rx2CJ method is based on atomistic reactive molecular dynamics (RMD) using the QM-derived ReaxFF force field. We validate this method here by predicting the CJ point and detonation products for three typical energetic materials. We find good agreement between the predicted and experimental detonation velocities, indicating that this method can reliably predict the CJ state using modest levels of computation.

  12. Thermal-Chemical Model Of Subduction: Results And Tests

    Science.gov (United States)

    Gorczyk, W.; Gerya, T. V.; Connolly, J. A.; Yuen, D. A.; Rudolph, M.

    2005-12-01

    Seismic structures with strong positive and negative velocity anomalies in the mantle wedge above subduction zones have been interpreted as thermally and/or chemically induced phenomena. We have developed a thermal-chemical model of subduction, which constrains the dynamics of seismic velocity structure beneath volcanic arcs. Our simulations have been calculated over a finite-difference grid with (201×101) to (201×401) regularly spaced Eulerian points, using 0.5 million to 10 billion markers. The model couples numerical thermo-mechanical solution with Gibbs energy minimization to investigate the dynamic behavior of partially molten upwellings from slabs (cold plumes) and structures associated with their development. The model demonstrates two chemically distinct types of plumes (mixed and unmixed), and various rigid body rotation phenomena in the wedge (subduction wheel, fore-arc spin, wedge pin-ball). These thermal-chemical features strongly perturb seismic structure. Their occurrence is dependent on the age of subducting slab and the rate of subduction.The model has been validated through a series of test cases and its results are consistent with a variety of geological and geophysical data. In contrast to models that attribute a purely thermal origin for mantle wedge seismic anomalies, the thermal-chemical model is able to simulate the strong variations of seismic velocity existing beneath volcanic arcs which are associated with development of cold plumes. In particular, molten regions that form beneath volcanic arcs as a consequence of vigorous cold wet plumes are manifest by > 20% variations in the local Poisson ratio, as compared to variations of ~ 2% expected as a consequence of temperature variation within the mantle wedge.

  13. Chemical environment of iron atoms in iron oxynitride films synthesized by reactive magnetron sputtering

    International Nuclear Information System (INIS)

    Grafoute, M.; Petitjean, C.; Rousselot, C.; Pierson, J.F.; Greneche, J.M.

    2007-01-01

    An iron oxynitride film was deposited on silicon and glass substrates by magnetron sputtering in an Ar-N 2 -O 2 reactive mixture. Rutherford back-scattering spectrometry was used to determine the film composition (Fe 1.06 O 0.35 N 0.65 ). X-ray diffraction revealed the formation of a face-centred cubic (fcc) structure with a lattice parameter close to that of γ'''-FeN. X-ray photoelectron spectroscopy showed the occurrence of Fe-N and Fe-O bonds in the film. The local environment of iron atoms studied by 57 Fe Moessbauer spectrometry at both 300 and 77 K gives clear evidence that the Fe 1.06 O 0.35 N 0.65 is not a mixture of iron oxide and iron nitride phases. Despite a small amount of an iron nitride phase, the main sample consists of an iron oxynitride phase with an NaCl-type structure where oxygen atoms partially substitute for nitrogen atoms, thus indicating the formation of a iron oxynitride with an fcc structure

  14. Role of human neurobehavioural tests in regulatory activity on chemicals

    Science.gov (United States)

    Stephens, R.; Barker, P.

    1998-01-01

    Psychological performance tests have been used since the mid-1960s in occupational and environmental health toxicology. The interpretation of significantly different test scores in neurobehavioural studies is not straightforward in the regulation of chemicals. This paper sets out some issues which emerged from discussions at an international workshop, organised by the United Kingdom Health and Safety Executive (HSE), to discuss differences in interpretation of human neurobehavioural test data in regulatory risk assessments. The difficulties encountered by regulators confronted with neurobehavioural studies seem to be twofold; some studies lack scientific rigor; other studies, although scientifically sound, are problematic because it is not clear what interpretation to place on the results. Issues relating to each of these points are discussed. Next, scenarios within which to consider the outcomes of neurobehavioural studies are presented. Finally, conclusions and recommendations for further work are put forward.   PMID:9624273

  15. Chemical products toxicological tests performed on lake and river fish

    International Nuclear Information System (INIS)

    Teulon, F.; Simeon, C.

    1966-01-01

    The volume and toxical values of industrial and urban effluents are growing higher and therefore acute or chronic pollution hazard is proportionally increased. Hence it is necessary to determine the effluent components minimum lethal dose for fish (one hour or six hours according to applicable standards). The following tests are described in this report: toxicity of some chemical products, tested individually (sodium, sulphate, sodium chloride, sodium fluoride, etc...); toxicity of some metal ions (Al 3+ , Fe ++ , Fe 3+ , Pb ++ , etc...); toxicity of certain mixed compounds for various fish species (sun perch, tench, gold fish, roach, gudgeon, bleak). The test results obtained represent local values and may be used for reference and as a general basis for other investigation and calculation of the effluents data when released. (author) [fr

  16. 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.

  17. Tautomeric transformation of temozolomide, their proton affinities and chemical reactivities: A theoretical approach.

    Science.gov (United States)

    Sang-Aroon, Wichien; Ruangpornvisuti, Vithaya; Amornkitbamrung, Vittaya

    2016-05-01

    The gas-phase geometry optimizations of bare, mono- and dihydrated complexes of temozolomide isomers were carried out using density functional calculation at the M06-2X/6-31+G(d,p) level of the theory. The structures and protonation energies of protonated species of temozolomide are reported. Chemical indices of all isomers and protonated species are also reported. Energies, thermodynamic quantities, rate constants and equilibrium constants of tautomeric and rotameric transformations of all isomers I1↔TZM↔HIa↔HIb↔I2↔I3 in bare and hydrated systems were obtained. Copyright © 2016 Elsevier Inc. All rights reserved.

  18. Role of tip chemical reactivity on atom manipulation process in dynamic force microscopy

    Czech Academy of Sciences Publication Activity Database

    Sugimoto, Y.; Yurtsever, A.; Abe, M.; Morita, S.; Ondráček, Martin; Pou, P.; Perez, R.; Jelínek, Pavel

    2013-01-01

    Roč. 7, č. 8 (2013), s. 7370-7376 ISSN 1936-0851 R&D Projects: GA ČR(CZ) GPP204/11/P578 Grant - others:GA AV ČR(CZ) M100101207 Institutional support: RVO:68378271 Keywords : noncontact atomic force microscopy * atomic manipulation * force spectroscopy * chemical interaction force * DFT simulations * nudged elastic band Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 12.033, year: 2013 http://pubs.acs.org/doi/abs/10.1021/nn403097p

  19. Molecular beam studies of hot atom chemical reactions: Reactive scattering of energetic deuterium atoms

    International Nuclear Information System (INIS)

    Continetti, R.E.; Balko, B.A.; Lee, Y.T.

    1989-02-01

    A brief review of the application of the crossed molecular beams technique to the study of hot atom chemical reactions in the last twenty years is given. Specific emphasis is placed on recent advances in the use of photolytically produced energetic deuterium atoms in the study of the fundamental elementary reactions D + H 2 /minus/> DH + H and the substitution reaction D + C 2 H 2 /minus/> C 2 HD + H. Recent advances in uv laser and pulsed molecular beam techniques have made the detailed study of hydrogen atom reactions under single collision conditions possible. 18 refs., 9 figs

  20. Molecular Beam Studies of Hot Atom Chemical Reactions: Reactive Scattering of Energetic Deuterium Atoms

    Science.gov (United States)

    Continetti, R. E.; Balko, B. A.; Lee, Y. T.

    1989-02-01

    A brief review of the application of the crossed molecular beams technique to the study of hot atom chemical reactions in the last twenty years is given. Specific emphasis is placed on recent advances in the use of photolytically produced energetic deuterium atoms in the study of the fundamental elementary reactions D + H{sub 2} -> DH + H and the substitution reaction D + C{sub 2}H{sub 2} -> C{sub 2}HD + H. Recent advances in uv laser and pulsed molecular beam techniques have made the detailed study of hydrogen atom reactions under single collision conditions possible.

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

    Science.gov (United States)

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

    2014-06-01

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

  2. Rapid and quantitative detection of C-reactive protein using quantum dots and immunochromatographic test strips

    Directory of Open Access Journals (Sweden)

    Cheng X

    2014-12-01

    Full Text Available Xianglin Cheng,1,* Xu Pu,2,* Pen Jun,3 XiaoBo Zhu,3 Di Zhu,4 Ming Chen1 1Department of Laboratory Medicine, First Affiliated Hospital of Yangtze University, Jingzhou, 2Department of Laboratory Medicine, RenMin Hospital of Wuhan University, Wuhan, 3Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education, College of Chemistry and Molecular Sciences, Wuhan University, Wuhan, Hubei, People’s Republic of China; 4Department of Medical Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA, USA *These authors contributed equally to this study and share first authorship Background: Rapid immunochromatographic tests can detect disease markers in 10–15 minutes, which facilitates clinical diagnosis and treatment programs. However, most immunochromatographic tests employ gold nanoparticles as reporters, and these have only moderate sensitivity and act as qualitative methods for analyzing high biomarker concentrations. Methods: In this study, we introduce quantum dots (QDs as fluorescent probes and immunochromatographic strips to develop quantitative fluorescence point-of-care tests (QF-POCT to analyze C-reactive protein (CRP levels. Goat anti-rabbit IgG and rabbit IgG were used as control antibodies, and mouse monoclonal CRP antibody pairs were used for disease marker detection. One monoclonal CRP antibody was conjugated with QDs and served as a signal antibody, and the other monoclonal CRP antibody was dispensed onto the nitrocellulose membrane and served as a capturing antibody. In the presence of CRP, the fluorescence intensity of the monoclonal antibody-CRP-monoclonal antibody sandwich complex captured on the nitrocellulose membrane was determined using the fluorescence strip reader. Results: QF-POCT assays could quantitatively analyze the concentration of CRP in 15 minutes had a detection limit of 0.25 mg/L, and had a wide detection linearity range (0.5–300 mg/L. The intra-assay and interassay

  3. Plasma exchange to remove HIT antibodies: dissociation between enzyme-immunoassay and platelet activation test reactivities.

    Science.gov (United States)

    Warkentin, Theodore E; Sheppard, Jo-Ann I; Chu, F Victor; Kapoor, Anil; Crowther, Mark A; Gangji, Azim

    2015-01-01

    Repeated therapeutic plasma exchange (TPE) has been advocated to remove heparin-induced thrombocytopenia (HIT) IgG antibodies before cardiac/vascular surgery in patients who have serologically-confirmed acute or subacute HIT; for this situation, a negative platelet activation assay (eg, platelet serotonin-release assay [SRA]) has been recommended as the target serological end point to permit safe surgery. We compared reactivities in the SRA and an anti-PF4/heparin IgG-specific enzyme immunoassay (EIA), testing serial serum samples in a patient with recent (subacute) HIT who underwent serial TPE precardiac surgery, as well as for 15 other serially-diluted HIT sera. We observed that post-TPE/diluted HIT sera-when first testing SRA-negative-continue to test strongly positive by EIA-IgG. This dissociation between the platelet activation assay and a PF4-dependent immunoassay for HIT antibodies indicates that patients with subacute HIT undergoing repeated TPE before heparin reexposure should be tested by serial platelet activation assays even when their EIAs remain strongly positive. © 2015 by The American Society of Hematology.

  4. Measurement of endotoxin. II. Comparison of reactivities measured by radioimmunoassay and with the limulus test

    Energy Technology Data Exchange (ETDEWEB)

    Kimura, H [Okayama Univ. (Japan). School of Medicine

    1976-08-01

    Various endotoxins and the ether extracts of grampositive bacteria were measured immunologically by radioimmunoassay and also biologically by the Limulus test. The minimum amount of endotoxin detectable with the Limulus test was in the range from 1 ng/ml to 1 ..mu..g/ml, with the lysate of sensitivity, 100 ng ml (E. coli 0111: B4(B) lipopolysaccharide). On the other hand, by the radioimmunoassay they were estimated in the range of 0.3 to 10 times of dry weight. Endotoxin-like activity was detected in the ether extracts of grampositive bacteria at a minimum concentration between 1 ..mu..g/ml and 100 ..mu..g/ml with the Limulus test. However, most of them were estimated by the radioimmunoassay to be under 1/50 of dry weight. Various substances such as thrombin, thromboplastin, polynosinic-polycytidylic acid, polyadenylic-polyuridylic acid, carrageenan and human colonic mucosal antigen had cross reactivities of various degrees in the minimum concentration from 10 ..mu..g/ml to 10 mg/ml. Compounds such as thrombin and thromboplastin cross-reacting in the Limulus test were scarcely measured by the radioimmunoassay except for polynucleotides. From this study, it has become clear that the radioimmunoassay method is quite specific and accurate for quantitative measurements of endotoxin.

  5. Test-retest reliability of an fMRI paradigm for studies of cardiovascular reactivity.

    Science.gov (United States)

    Sheu, Lei K; Jennings, J Richard; Gianaros, Peter J

    2012-07-01

    We examined the reliability of measures of fMRI, subjective, and cardiovascular reactions to standardized versions of a Stroop color-word task and a multisource interference task. A sample of 14 men and 12 women (30-49 years old) completed the tasks on two occasions, separated by a median of 88 days. The reliability of fMRI BOLD signal changes in brain areas engaged by the tasks was moderate, and aggregating fMRI BOLD signal changes across the tasks improved test-retest reliability metrics. These metrics included voxel-wise intraclass correlation coefficients (ICCs) and overlap ratio statistics. Task-aggregated ratings of subjective arousal, valence, and control, as well as cardiovascular reactions evoked by the tasks showed ICCs of 0.57 to 0.87 (ps reliability. These findings support using these tasks as a battery for fMRI studies of cardiovascular reactivity. Copyright © 2012 Society for Psychophysiological Research.

  6. Comparative Studies on Dyeability with Direct, Acid and Reactive Dyes after Chemical Modification of Jute with Mixed Amino Acids Obtained from Extract of Waste Soya Bean Seeds

    Science.gov (United States)

    Bhaumik, Nilendu Sekhar; Konar, Adwaita; Roy, Alok Nath; Samanta, Ashis Kumar

    2017-12-01

    Jute fabric was treated with mixed natural amino acids obtained from waste soya bean seed extract for chemical modification of jute for its cataionization and to enhance its dyeability with anionic dyes (like direct, reactive and acid dye) as well enabling soya modified jute for salt free dyeing with anionic reactive dyes maintaining its eco-friendliness. Colour interaction parameters including surface colour strength were assessed and compared for both bleached and soya-modified jute fabric for reactive dyeing and compared with direct and acid dye. Improvement in K/S value (surface colour strength) was observed for soya-modified jute even in absence of salt applied in dye bath for reactive dyes as well as for direct and acid dyes. In addition, reactive dye also shows good dyeability even in acid bath in salt free conditions. Colour fastness to wash was evaluated for bleached and soya-modified jute fabric after dyeing with direct, acid and reactive dyes are reported. Treatment of jute with soya-extracted mixed natural amino acids showed anchoring of some amino/aldemine groups on jute cellulosic polymer evidenced from Fourier Transform Infra-Red (FTIR) Spectroscopy. This amino or aldemine group incorporation in bleached jute causes its cationization and hence when dyed in acid bath for reactive dye (instead of conventional alkali bath) showed dye uptake for reactive dyes. Study of surface morphology by Scanning Electron Microscopy (SEM) of said soya-modified jute as compared to bleached jute was studied and reported.

  7. Formulation of chemically reactive foams for the dissolution of oxides polluting the secondary circuits of steam generators

    International Nuclear Information System (INIS)

    Provens, Helene

    1999-01-01

    The fouling of the Steam Generators (SG) secondary circuits, due to oxides deposits like magnetite (Fe 3 O 4 ), induces the degradation of the internal SG equipment, the reduction of the plant power, implying to clean these circuits. This operation made in liquid phase generates an important volume of effluents with an expensive cost of treatment. The use of a reactive foam allows the reduction of this volume by ten. Among the reactive tested, oxalic acid is the most efficient to dissolve a magnetite quantity of 10 g.l -1 , at ambient temperature for 24 hours, as imposed by the industrial wishes. The dissolution is not complete in our experimental conditions and is a complex reaction of autocatalytic type, composed of an acid attack, a reductive step, both followed by a slow diffusion. The surfactants generating the foam, which transport the reactive, are adsorbed on the magnetite but this affects weakly the dissolution. Its effectiveness is evaluated varying the experimental conditions. The wetting properties and the stability of the foam induce erosion and undissolved particles transport capacities, during its circulation into the SG. These particles trapped in the inter-bubble liquid films or carried by the piston effect of the foam bed, can be recovered on filters placed out of the SG. To quantify the transport, the influence of different parameters is studied: the more stable the foam is, the more important the transport is. Innocuousness tests showed that oxalic acid was not harmful for constitutive SG materials, either they were isolated or coupled. The cleaning by oxalic acid causes ferrous oxalates precipitation, representing 10 to 15 pc of the total iron quantity depending on the sample. A rinsing out with a foam containing 1 pc oxalic acid and 5 pc hydrogen peroxide allows the dissolution of these precipitates without corrosion problems. (author) [fr

  8. Analysis of excess reactivity of JOYO MK-III performance test core

    International Nuclear Information System (INIS)

    Maeda, Shigetaka; Yokoyama, Kenji

    2003-10-01

    JOYO is currently being upgraded to the high performance irradiation bed JOYO MK-III core'. The MK-III core is divided into two fuel regions with different plutonium contents. To obtain a higher neutron flux, the active core height was reduced from 55 cm to 50 cm. The reflector subassemblies were replaced by shielding subassemblies in the outer two rows. Twenty of the MK-III outer core fuel subassemblies in the performance test core were partially burned in the transition core. Four irradiation test rigs, which do not contain any fuel material, were loaded in the center of the performance test core. In order to evaluate the excess reactivity of MK-III performance test core accurately, we evaluated it by applying not only the JOYO MK-II core management code system MAGI, but also the MK-III core management code system HESTIA, the JUPITER standard analysis method and the Monte Carlo method with JFS-3-J3.2R content set. The excess reactivity evaluations obtained by the JUPITER standard analysis method were corrected to results based on transport theory with zero mesh-size in space and angle. A bias factor based on the MK-II 35th core, which sensitivity was similar to MK-III performance test core's, was also applied, except in the case where an adjusted nuclear cross-section library was used. Exact three-dimensional, pin-by-pin geometry and continuous-energy cross sections were used in the Monte Carlo calculation. The estimated error components associated with cross-sections, methods correction factors and the bias factor were combined based on Takeda's theory. Those independently calculated values agree well and range from 2.8 to 3.4%Δk/kk'. The calculation result of the MK-III core management code system HESTLA was 3.13% Δk/kk'. The estimated errors for bias method range from 0.1 to 0.2%Δk/kk'. The error in the case using adjusted cross-section was 0.3%Δk/kk'. (author)

  9. Modeling of reactive chemical transport of leachates from a utility fly-ash disposal site

    International Nuclear Information System (INIS)

    Apps, J.A.; Zhu, M.; Kitanidis, P.K.; Freyberg, D.L.; Ronan, A.D.; Itakagi, S.

    1991-04-01

    Fly ash from fossil-fuel power plants is commonly slurried and pumped to disposal sites. The utility industry is interested in finding out whether any hazardous constituents might leach from the accumulated fly ash and contaminate ground and surface waters. To evaluate the significance of this problem, a representative site was selected for modeling. FASTCHEM, a computer code developed for the Electric Power Research Institute, was utilized for the simulation of the transport and fate of the fly-ash leachate. The chemical evolution of the leachate was modeled as it migrated along streamtubes defined by the flow model. The modeling predicts that most of the leachate seeps through the dam confining the ash pond. With the exception of ferrous, manganous, sulfate and small amounts of nickel ions, all other dissolved constituents are predicted to discharge at environmentally acceptable concentrations

  10. Response of the ionosphere to the injection of chemically reactive vapors

    International Nuclear Information System (INIS)

    Bernhardt, P.A.

    1976-05-01

    As a gas released in the ionosphere expands, it is rapidly cooled. When the vapor becomes sufficiently tenuous, it is reheated by collisions with the ambient atmosphere, and its flow is then governed by diffusive expansion. As the injected gas becomes well mixed with the plasma, a hole is created by chemical processes. In the case of diatomic hydrogen release, depression of the electron concentrations is governed by the charge exchange reaction between oxygen ions and hydrogen, producing positive hydroxyl ions. Hydroxyl ions rapidly react with the electron gas to produce excited oxygen and hydrogen atoms. Enhanced airglow emissions result from the transition of the excited atoms to lower energy states. The electron temperature in the depleted region rises sharply and this rise causes a thermal expansion of the plasma and a further reduction in the local plasma concentration

  11. Reliability of heart rate variability threshold and parasympathetic reactivation after a submaximal exercise test

    Directory of Open Access Journals (Sweden)

    Carlos Janssen Gomes da Cruz

    Full Text Available Abstract The objective of this study was to evaluate reproducibility of heart rate variability threshold (HRVT and parasympathetic reactivation in physically active men (n= 16, 24.3 ± 5.1 years. During the test, HRVT was assessed by SD1 and r-MSSD dynamics. Immediately after exercise, r-MSSD was analyzed in segments of 60 seconds for a period of five minutes. High absolute and relatively reproducible analysis of HRVT were observed, as assessed by SD1 and r-MSSD dynamics (ICC = 0.92, CV = 10.8, SEM = 5.8. During the recovery phase, a moderate to high reproducibility was observed for r-MSSD from the first to the fifth minute (ICC = 0.69-0.95, CV = 7.5-14.2, SEM = 0.07-1.35. We conclude that HRVT and r-MSSD analysis after a submaximal stress test are highly reproducible measures that might be used to assess the acute and chronic effects of exercise training on cardiac autonomic modulation during and/or after a submaximal stress test.

  12. Electron Transfer Reactivity Patterns at Chemically Modified Electrodes: Fundamentals and Application to the Optimization of Redox Recycling Amplification Systems

    Energy Technology Data Exchange (ETDEWEB)

    Bergren, Adam Johan [Iowa State Univ., Ames, IA (United States)

    2006-01-01

    Electroanalytical chemistry is often utilized in chemical analysis and Fundamental studies. Important advances have been made in these areas since the advent of chemically modified electrodes: the coating of an electrode with a chemical film in order to impart desirable, and ideally, predictable properties. These procedures enable the exploitation of unique reactivity patterns. This dissertation presents studies that investigate novel reaction mechanisms at self-assembled monolayers on gold. In particular, a unique electrochemical current amplification scheme is detailed that relies on a selective electrode to enable a reactivity pattern that results in regeneration of the analyte (redox recycling). This regenerating reaction can occur up to 250 times for each analyte molecule, leading to a notable enhancement in the observed current. The requirements of electrode selectivity and the resulting amplification and detection limit improvements are described with respect to the heterogeneous and homogeneous electron transfer rates that characterize the system. These studies revealed that the heterogeneous electrolysis of the analyte should ideally be electrochemically reversible, while that for the regenerating agent should be held to a low level. Moreover, the homogeneous reaction that recycles the analyte should occur at a rapid rate. The physical selectivity mechanism is also detailed with respect to the properties of the electrode and redox probes utilized. It is shown that partitioning of the analyte into/onto the adlayer leads to the extraordinary selectivity of the alkanethiolate monolayer modified electrode. Collectively, these studies enable a thorough understanding of the complex electrode mechanism required for successful redox recycling amplification systems, Finally, in a separate (but related) study, the effect of the akyl chain length on the heterogeneous electron transfer behavior of solution-based redox probes is reported, where an odd-even oscillation

  13. Reactivity feedback coefficients of a low enriched uranium fuelled material test research reactor at end-of-life

    International Nuclear Information System (INIS)

    Muhammad, Farhan

    2011-01-01

    Highlights: → The isotopic concentration in the fuel changes as soon as it starts its operation. → The neutronic properties of a reactor also change with fuel burnup. → The reactivity feedbacks at end-of-life of a material test reactor fuelled with low enriched uranium fuel are calculated. → Codes used include WIMS-D4 and CITATION. - Abstract: The reactivity feedback coefficients at end-of-life of a material test reactor fuelled with low enriched uranium fuel were calculated. The reactor used for the study was the IAEA's 10 MW benchmark reactor. Simulations were carried out to calculate the different reactivity feedback coefficients including Doppler feedback coefficient, reactivity coefficient for change of water temperature and reactivity coefficient for change of water density. Nuclear reactor analysis codes including WIMS-D4 and CITATION were employed to carry out these calculations. It was observed that the magnitude of all the reactivity feedback coefficients increased at end of life of the reactor by almost 2-5%.

  14. Unsaturated fatty acids show clear elicitation responses in a modified local lymph node assay with an elicitation phase, and test positive in the direct peptide reactivity assay.

    Science.gov (United States)

    Yamashita, Kunihiko; Shinoda, Shinsuke; Hagiwara, Saori; Miyazaki, Hiroshi; Itagaki, Hiroshi

    2015-12-01

    The Organisation for Economic Co-operation and Development (OECD) Test Guidelines (TG) adopted the murine local lymph node assay (LLNA) and guinea pig maximization test (GPMT) as stand-alone skin sensitization test methods. However, unsaturated carbon-carbon double-bond and/or lipid acids afforded false-positive results more frequently in the LLNA compared to those in the GPMT and/or in human subjects. In the current study, oleic, linoleic, linolenic, undecylenic, fumaric, maleic, and succinic acid and squalene were tested in a modified LLNA with an elicitation phase (LLNA:DAE), and in a direct peptide reactivity assay (DPRA) to evaluate their skin-sensitizing potential. Oleic, linoleic, linolenic, undecylenic and maleic acid were positive in the LLNA:DAE, of which three, linoleic, linolenic, and maleic acid were positive in the DPRA. Furthermore, the results of the cross-sensitizing tests using four LLNA:DAE-positive chemicals were negative, indicating a chemical-specific elicitation response. In a previous report, the estimated concentration needed to produce a stimulation index of 3 (EC3) of linolenic acid, squalene, and maleic acid in the LLNA was LLNA. However, the skin-sensitizing potential of all LLNA:DAE-positive chemicals was estimated as weak. These results suggested that oleic, linoleic, linolenic, undecylenic, and maleic acid had skin-sensitizing potential, and that the LLNA overestimated the skin-sensitizing potential compared to that estimated by the LLNA:DAE.

  15. Physico-chemical changes of the ground waters related to the 2011 El Hierro magmatic reactivation

    Science.gov (United States)

    Dionis, S.; Melián, G.; Padrón, E.; Padilla, G.; Nolasco, D.; Rodríguez, F.; Hernández, I.; Peraza, D.; Barrancos, J.; Hernández, P.; Calvo, D.; Pérez, N.

    2012-04-01

    The island of El Hierro (278 Km2), is the smallest, the southwesternmost and the youngest island (˜1.12 My) of the Canarian archipelago. The main geological characteristics of El Hierro consist on the presence of three convergent ridges of volcanic cones on a truncated trihedron shape and giant landslides between the three rift zones, being the most recent El Golfo on the northwest flank of the island. On July 2011 an anomalous seismic activity at Hierro Island started and suggested the initial stage of a volcanic unrest in the volcanic system. On October 10, after the occurrence of more than 10,000 earthquakes, a submarine eruption started. Evidences of this submarine volcanic eruption were visible on the sea surface to the south of La Restinga village, at the south of the island, in the form of large light-green coloured area, turbulent gas emission and the appearance of steamy volcanic fragments three days later. As part of its volcanic surveillance activities, the Instituto Volcanologico de Canarias (INVOLCAN) started a hydrogeochemical monitoring program on August 2011 in order to evaluate the temporal evolution of several physico-chemical parameters of the ground water system of El Hierro. Four observation sites were selected: three wells on the north of the island, where the seismic activity was located at the beginning of the volcano-seismic unrest (SIMO, FRON and PADO) and one horizontal well (gallery) in the south (TACO). Ground water sampling is being regularly collected, three times per week, at each observation site, and in-situ measurements of pH, conductivity and temperature measurements are performed. After 6 month of monitoring, no significant changes have been observed on pH and temperature measurements from all the observation sites. However, clear sharp decrease of conductivity was observed at SIMO on October 10 when the seismic tremor started. In addition, the strongest conductivity decrease pattern was observed later on at SIMO and PADO on

  16. Vibrational deactivation on chemically reactive potential surfaces: An exact quantum study of a low barrier collinear model of H + FH, D + FD, H + FD and D + FH

    International Nuclear Information System (INIS)

    Schatz, G.C.; Kuppermann, A.

    1980-01-01

    We study vibrational deactivation processes on chemically reactive potential energy surfaces by examining accurate quantum mechanical transition probabilities and rate constants for the collinear H + FH(v), D + FD(v), H + FD(v), and D + FH(v) reactions. A low barrier (1.7 kcal/mole) potential surface is used in these calculations, and we find that for all four reactions, the reactive inelastic rate constants are larger than the nonreactive ones for the same initial and final vibrational states. However, the ratios of these reactive and nonreactive rate constants depend strongly on the vibrational quantum number v and the isotopic composition of the reagents. Nonreactive and reactive transition probabilities for multiquantum jump transitions are generally comparable to those for single quantum transitions. This vibrationally nonadiabatic behavior is a direct consequence of the severe distortion of the diatomic that occurs in a collision on a low barrier reactive surface, and can make chemically reactive atoms like H or D more efficient deactivators of HF or DF than nonreactive collision partners. Many conclusions are in at least qualitative agreement with those of Wilkin's three dimensional quasiclassical trajectory study on the same systems using a similar surface. We also present results for H + HF(v) collisions which show that for a higher barrier potential surface (33 rather than 1.7 kcal/mole), the deactivation process becomes similar in character to that for nonreactive partners, with v→v-1 processes dominating

  17. Corrosion resistance and electrochemical potentiokinetic reactivation testing of some iron-base hardfacing alloys

    International Nuclear Information System (INIS)

    Cockeram, B.V.

    1999-01-01

    Hardfacing alloys are weld deposited on a base material to provide a wear resistant surface. Commercially available iron-base hardfacing alloys are being evaluated for replacement of cobalt-base alloys to reduce nuclear plant activation levels. Corrosion testing was used to evaluate the corrosion resistance of several iron-base hardfacing alloys in highly oxygenated environments. The corrosion test results indicate that iron-base hardfacing alloys in the as-deposited condition have acceptable corrosion resistance when the chromium to carbon ratio is greater than 4. Tristelle 5183, with a high niobium (stabilizer) content, did not follow this trend due to precipitation of niobium-rich carbides instead of chromium-rich carbides. This result indicates that iron-base hardfacing alloys containing high stabilizer contents may possess good corrosion resistance with Cr:C < 4. NOREM 02, NOREM 01, and NoCo-M2 hardfacing alloys had acceptable corrosion resistance in the as-deposited and 885 C/4 hour heat treated condition, but rusting from sensitization was observed in the 621 C/6 hour heat treated condition. The feasibility of using an Electrochemical Potentiokinetic Reactivation (EPR) test method, such as used for stainless steel, to detect sensitization in iron-base hardfacing alloys was evaluated. A single loop-EPR method was found to provide a more consistent measurement of sensitization than a double loop-EPR method. The high carbon content that is needed for a wear resistant hardfacing alloy produces a high volume fraction of chromium-rich carbides that are attacked during EPR testing. This results in inherently lower sensitivity for detection of a sensitized iron-base hardfacing alloy than stainless steel using conventional EPR test methods

  18. Stress Reactivity to an Electronic Version of the Trier Social Stress Test: A Pilot Study

    Directory of Open Access Journals (Sweden)

    Sage E Hawn

    2015-05-01

    Full Text Available Social stressors that rely on the inclusion of confederates (i.e., Trier Social Stress Test; TSST are often used in clinical laboratory research paradigms to elicit a measurable stress response in participants. Although effective, the TSST is labor intensive and may introduce error variance as a function of confederate race, gender, and/or response characteristics. The present study aimed to develop and validate an electronic version of the TSST (e-TSST. The primary aim was to compare the e-TSST to an e-neutral control condition; the exploratory aim was to compare the magnitude of stress response elicited by the e-TSST to that elicited by the traditional TSST. Forty-three healthy adults were randomized to the e-TSST or e-neutral condition. Subjective (participant-rated distress and objective (cortisol, heart rate and blood pressure indices of stress were collected prior to, and multiple times following, the stressor. Using archival data collected from 19 healthy participants exposed to the traditional TSST in a prior study, stress reactivity was compared between the electronic and traditional versions of the TSST. The e-TSST elicited significant increases in all measures of stress reactivity compared to the e-neutral condition, with the exception of heart rate (HR. Results showed that the magnitude of subjective distress, BP, and HR responses elicited by the e-TSST did not differ significantly from that elicited by the traditional TSST. The traditional TSST elicited significantly higher cortisol than the e-TSST. Although these findings provide initial support for the development of electronic versions of the TSST, further refinement of the e-TSST is warranted prior to broad adoption of this technology. A refined, reliable e-TSST could allow for increased utilization of the TSST by enhancing convenience, reducing labor costs, and limiting potential error variance introduced by human confederates.

  19. Numerical solution of chemically reactive non-Newtonian fluid flow: Dual stratification

    Science.gov (United States)

    Rehman, Khalil Ur; Malik, M. Y.; Khan, Abid Ali; Zehra, Iffat; Zahri, Mostafa; Tahir, M.

    2017-12-01

    We have found that only a few attempts are available in the literature relatively to the tangent hyperbolic fluid flow induced by stretching cylindrical surfaces. In particular, temperature and concentration stratification effects have not been investigated until now with respect to the tangent hyperbolic fluid model. Therefore, we have considered the tangent hyperbolic fluid flow induced by an acutely inclined cylindrical surface in the presence of both temperature and concentration stratification effects. To be more specific, the fluid flow is attained with the no slip condition, which implies that the bulk motion of the fluid particles is the same as the stretching velocity of a cylindrical surface. Additionally, the flow field situation is manifested with heat generation, mixed convection and chemical reaction effects. The flow partial differential equations give a complete description of the present problem. Therefore, to trace out the solution, a set of suitable transformations is introduced to convert these equations into ordinary differential equations. In addition, a self-coded computational algorithm is executed to inspect the numerical solution of these reduced equations. The effect logs of the involved parameters are provided graphically. Furthermore, the variations of the physical quantities are examined and given with the aid of tables. It is observed that the fluid temperature is a decreasing function of the thermal stratification parameter and a similar trend is noticed for the concentration via the solutal stratification parameter.

  20. Chemical reactivity of precursor materials during synthesis of glasses used for conditioning high-level radioactive waste: Experiments and models

    International Nuclear Information System (INIS)

    Monteiro, A.

    2012-01-01

    The glass used to store high-level radioactive waste is produced by reaction of a solid waste residue and a glassy precursor (glass frit). The waste residue is first dried and calcined (to lose water and nitrogen respectively), then mixed with the glass frit to enable vitrification at high temperature. In order to obtain a good quality glass of constant composition upon cooling, the chemical reactions between the solid precursors must be complete while in the liquid state, to enable incorporation of the radioactive elements into the glassy matrix. The physical and chemical conditions during glass synthesis (e.g. temperature, relative proportions of frit and calcine, amount of radioactive charge) are typically empirically adjusted to obtain a satisfactory final product. The aim of this work is to provide new insights into the chemical and physical interactions that take place during vitrification and to provide data for a mathematical model that has been developed to simulate the chemical reactions. The consequences of the different chemical reactions that involve solid, liquid and gaseous phases are described (thermal effects, changes in crystal morphology and composition, variations in melt properties and structure). In a first series of experiments, a simplified analogue of the calcine (NaNO 3 -Al 2 O 3 ± MoO 3 /Nd 2 O 3 ) has been studied. In a second series of experiments, the simplified calcines have been reacted with a simplified glass frit (SiO 2 -Na 2 O-B 2 O 3 -Al 2 O 3 ) at high temperature. The results show that crystallization of the calcine may take place before interaction with the glass frit, but that the reactivity with the glass at high temperature is a function of the nature and stoichiometry of the crystalline phases which form at low temperature. The results also highlight how the mixing of the starting materials, the physical properties of the frit (viscosity, glass transition temperature) and the Na 2 O/Al 2 O 3 of the calcine but also its

  1. Allium -test as a tool for toxicity testing of environmental radioactive-chemical mixtures

    International Nuclear Information System (INIS)

    Oudalova, A A; Pyatkova, S V; Geras’kin, S A; Dikareva, N S

    2017-01-01

    Bioassay-based approaches have been propagated to assess toxicity of unknown mixtures of environmental contaminants, but it was rarely applied in cases of chemicals with radionuclides combinations. Two Allium -test studies were performed to assess environmental impact from potential sources of combined radioactive-chemical pollution. Study sites were located at nuclear waste storage facilities in European and in Far-Eastern parts of Russia. As environmental media under impact, waters from monitor wells and nearby water bodies were tested. Concentrations of some chemicals and radionuclides in the samples collected enhanced the permitted limits. Cytogenetic and cytotoxic effects were used as biological endpoints, namely, frequency and spectrum of chromosome aberrations and mitotic abnormalities in anatelophase cells as well as mitotic activity in Allium root tips. Sample points were revealed where waters have an enhanced mutagenic potential. The findings obtained could be used to optimize monitoring system and advance decision making on management and rehabilitation of industrial sites. The Allium -test could be recommended and applied as an effective tool for toxicity testing in case of combined contamination of environmental compartments with radionuclides and chemical compounds. (paper)

  2. Allium-test as a tool for toxicity testing of environmental radioactive-chemical mixtures

    Science.gov (United States)

    Oudalova, A. A.; Geras'kin, S. A.; Dikareva, N. S.; Pyatkova, S. V.

    2017-01-01

    Bioassay-based approaches have been propagated to assess toxicity of unknown mixtures of environmental contaminants, but it was rarely applied in cases of chemicals with radionuclides combinations. Two Allium-test studies were performed to assess environmental impact from potential sources of combined radioactive-chemical pollution. Study sites were located at nuclear waste storage facilities in European and in Far-Eastern parts of Russia. As environmental media under impact, waters from monitor wells and nearby water bodies were tested. Concentrations of some chemicals and radionuclides in the samples collected enhanced the permitted limits. Cytogenetic and cytotoxic effects were used as biological endpoints, namely, frequency and spectrum of chromosome aberrations and mitotic abnormalities in anatelophase cells as well as mitotic activity in Allium root tips. Sample points were revealed where waters have an enhanced mutagenic potential. The findings obtained could be used to optimize monitoring system and advance decision making on management and rehabilitation of industrial sites. The Allium-test could be recommended and applied as an effective tool for toxicity testing in case of combined contamination of environmental compartments with radionuclides and chemical compounds.

  3. Allergic contact dermatitis due to highly reactive halogenated compounds

    Energy Technology Data Exchange (ETDEWEB)

    Pickering, F C; Ive, F A

    1983-11-01

    Ten cases of dermatitis in a fine organic chemicals plant are reported. These cases were all due to exposure to chemical compounds with reactive bromine or chlorine atoms. This type of chemical is always extremely irritant, but evidence is put forward to suggest that these cases were the result of allergic sensitization. Chemicals with reactive halogen atoms should always be handled with extreme care and patch testing should be approached with caution.

  4. Influence of the physicochemical and aromatic properties on the chemical reactivity and its relation with carcinogenic and anticoagulant effect of 17β-aminoestrogens

    Energy Technology Data Exchange (ETDEWEB)

    Soriano-Correa, Catalina, E-mail: socc@puma2.zaragoza.unam.mx [Química Computacional, FES-Zaragoza, Universidad Nacional Autónoma de México (UNAM), Iztapalapa, Mexico City (Mexico); Raya, Angélica [Unidad Profesional Interdisciplinaria de Ingeniería Campus Guanajuato, Instituto Politécnico Nacional (IPN), Silao de la Victoria, Guanajuato (Mexico); Barrientos-Salcedo, Carolina [Laboratorio de Química Médica y Quimiogenómica, Facultad de Bioanálisis Campus Veracruz - Boca del Río, Universidad Veracruzana, Veracruz (Mexico); Esquivel, Rodolfo O. [Departamento de Química, Universidad Autónoma Metropolitana-Iztapalapa (UAM-Iztapalapa), Mexico City (Mexico)

    2014-06-25

    Highlights: • The aromatic A-ring of 17β-aminoestrogens contribute to its anticoagulant effect. • The electron-donor substituent groups favored the basicity of 17β-aminoestrogens. • The physicochemical properties are important in the carcinogenic effect of anticoagulant molecules. - Abstract: Activity of steroid hormones is dependent upon a number of factors, as solubility, transport and metabolism. The functional differences caused by structural modifications could exert an influence on the chemical reactivity and biological effect. The goal of this work is to study the influence of the physicochemical and aromatic properties on the chemical reactivity and its relation with the carcinogenic risk that can associate with the anticoagulant effect of 17β-aminoestrogens using quantum-chemical descriptors at the DFT-B3LYP, BH and HLYP and M06-2X levels. The relative acidity of (H1) of the hydroxyl group increases with electron-withdrawing groups. Electron-donor groups favor the basicity. The steric hindrance of the substituents decreases the aromatic character and consequently diminution the carcinogenic effect. Density descriptors: hardness, electrophilic index, atomic charges, molecular orbitals, electrostatic potential and their geometric parameters permit analyses of the chemical reactivity and physicochemical features and to identify some reactive sites of 17β-aminoestrogens.

  5. Synthesis, characterisation and chemical reactivity of some new binuclear dioxouranium(VI) complexes derived from organic diazo compounds (Preprint No. CT-33)

    International Nuclear Information System (INIS)

    Pujar, M.A.; Pirgonde, B.R.

    1988-02-01

    A new series of binuclear dioxouranium(VI) complexes of polydentatate diazo compounds have been synthesised and characterised adequately by analysis, physio-chemical techniques and reactivity of these complexes. The location of bonding site of ligands, stability of complexes and status of U-O bond and probable structures of these complexes have been discussed. (author). 10 refs

  6. Fuels and chemicals from equine-waste-derived tail gas reactive pyrolysis oil: technoeconomic analysis, environmental and exergetic life cycle assessment

    Science.gov (United States)

    Horse manure, whose improper disposal imposes considerable environmental costs, constitutes an apt feedstock for conversion to renewable fuels and chemicals when tail gas reactive pyrolysis (TGRP) is employed. TGRP is a modification of fast pyrolysis that recycles its non-condensable gases and produ...

  7. Temperature buffer test. Hydro-mechanical and chemical/ mineralogical characterizations

    Energy Technology Data Exchange (ETDEWEB)

    Aakesson, Mattias; Olsson, Siv; Dueck, Ann; Nilsson, Ulf; Karnland, Ola [Clay Technology AB, Lund (Sweden); Kiviranta, Leena; Kumpulainen, Sirpa [BandTech Oy, Helsinki (Finland); Linden, Johan [Aabo Akademi, Aabo (Finland)

    2012-01-15

    The Temperature Buffer Test (TBT) is a joint project between SKB/ANDRA and supported by ENRESA (modeling) and DBE (instrumentation), which aims at improving the understanding and to model the thermo-hydro-mechanical behavior of buffers made of swelling clay submitted to high temperatures (over 100 deg C) during the water saturation process. The test has been carried out in a KBS-3 deposition hole at Aspo HRL. It was installed during the spring of 2003. Two steel heaters (3 m long, 0.6 m diameter) and two buffer arrangements have been investigated: the lower heater was surrounded by rings of compacted Wyoming bentonite only, whereas the upper heater was surrounded by a composite barrier, with a sand shield between the heater and the bentonite. The test was dismantled and sampled during the winter of 2009/2010. This report presents the hydro-mechanical and chemical/mineralogical characterization program which was launched subsequent to the dismantling operation. The main goal has been to investigate if any significant differences could be observed between material from the field experiment and the reference material. The field samples were mainly taken from Ring 4 (located at the mid-section around the lower heater), in which the temperature in the innermost part reached 155 deg C. The following hydro-mechanical properties have been determined for the material (test technique within brackets): hydraulic conductivity (swelling pressure device), swelling pressure (swelling pressure device), unconfined compression strength (mechanical press), shear strength (triaxial cell) and retention properties (jar method). The following chemical/mineralogical properties (methods within brackets) were determined: anion analysis of water leachates (IC), chemical composition (ICP/AES+MS, EGA), cation exchange capacity (CEC, Cu-trien method) and exchangeable cations (exchange with NH4, ICPAES), mineralogical composition (XRD and FTIR), element distribution and microstructure (SEM and

  8. 40 CFR 799.5115 - Chemical testing requirements for certain chemicals of interest to the Occupational Safety and...

    Science.gov (United States)

    2010-07-01

    ... hearing officer chooses to use a formula based on production volume, the total production volume amount...) How must I conduct my testing? The chemical substances identified by Chemical Abstract Service...., Whittaker, C. and McDougal, J.N. Role of the TSCA Interagency Testing Committee in Meeting the U.S...

  9. Coupling Chemical Kinetics and Flashes in Reactive, Thermal and Compositional Reservoir Simulation

    DEFF Research Database (Denmark)

    Kristensen, Morten Rode; Gerritsen, Margot G.; Thomsen, Per Grove

    2007-01-01

    of convergence and error test failures by more than 50% compared to direct integration without the new algorithm. To facilitate the algorithmic development we construct a virtual kinetic cell model. We use implicit one-step ESDIRK (Explicit Singly Diagonal Implicit Runge-Kutta) methods for integration......Phase changes are known to cause convergence problems for integration of stiff kinetics in thermal and compositional reservoir simulations. We propose an algorithm for detection and location of phase changes based on discrete event system theory. The algorithm provides a robust way for handling...... the switching of variables and equations required when the number of phases changes. We extend the method to handle full phase equilibrium described by an equation of state. Experiments show that the new algorithm improves the robustness of the integration process near phase boundaries by lowering the number...

  10. Similarity Analysis of Cable Insulations by Chemical Test

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jong Seog [Central Research Institute of Korea Hydro and Nuclear Power Co., Daejeon (Korea, Republic of)

    2013-10-15

    As result of this experiment, it was found that FT-IR test for material composition, TGA test for aging trend are applicable for similarity analysis of cable materials. OIT is recommended as option if TGA doesn't show good trend. Qualification of new insulation by EQ report of old insulation should be based on higher activation energy of new insulation than that of old one in the consideration of conservatism. In old nuclear power plant, it is easy to find black cable which has no marking of cable information such as manufacturer, material name and voltage. If a type test is required for qualification of these cables, how could I select representative cable? How could I determine the similarity of these cables? If manufacturer has qualified a cable for nuclear power plant more than a decade ago and composition of cable material is changed with similar one, is it acceptable to use the old EQ report for recently manufactured cable? It is well known to use FT-IR method to determine the similarity of cable materials. Infrared ray is easy tool to compare compositions of each material. But, it is not proper to compare aging trend of these materials. Study for similarity analysis of cable insulation by chemical test is described herein. To study a similarity evaluation method for polymer materials, FT-IR, TGA and OIT tests were performed for two cable insulation(old and new) which were supplied from same manufacturer. FT-IR shows good result to compare material compositions while TGA and OIT show good result to compare aging character of materials.

  11. Similarity Analysis of Cable Insulations by Chemical Test

    International Nuclear Information System (INIS)

    Kim, Jong Seog

    2013-01-01

    As result of this experiment, it was found that FT-IR test for material composition, TGA test for aging trend are applicable for similarity analysis of cable materials. OIT is recommended as option if TGA doesn't show good trend. Qualification of new insulation by EQ report of old insulation should be based on higher activation energy of new insulation than that of old one in the consideration of conservatism. In old nuclear power plant, it is easy to find black cable which has no marking of cable information such as manufacturer, material name and voltage. If a type test is required for qualification of these cables, how could I select representative cable? How could I determine the similarity of these cables? If manufacturer has qualified a cable for nuclear power plant more than a decade ago and composition of cable material is changed with similar one, is it acceptable to use the old EQ report for recently manufactured cable? It is well known to use FT-IR method to determine the similarity of cable materials. Infrared ray is easy tool to compare compositions of each material. But, it is not proper to compare aging trend of these materials. Study for similarity analysis of cable insulation by chemical test is described herein. To study a similarity evaluation method for polymer materials, FT-IR, TGA and OIT tests were performed for two cable insulation(old and new) which were supplied from same manufacturer. FT-IR shows good result to compare material compositions while TGA and OIT show good result to compare aging character of materials

  12. Endocrine disrupting chemicals: harmful substances and how to test them

    Directory of Open Access Journals (Sweden)

    Olea-Serrano Nicolás

    2002-01-01

    Full Text Available This paper presents an analysis of the opinions of different groups from: scientists, international regulatory bodies, non-governmental organizations and industry; with an interest in the problem of identifying chemical substances with endocrine disrupting activity. There is also discussion of the consequences that exposure to endocrine disruptors may have for human health, considering concrete issues related to: the estimation of risk; the tests that must be used to detect endocrine disruption; the difficulties to establish an association between dose, time of exposure, individual susceptibility, and effect; and the attempts to create a census of endocrine disruptors. Finally, it is proposed that not all hormonal mimics should be included under the single generic denomination of endocrine disruptors.

  13. On the mechanisms associated with the chemical reactivity of Be in steam

    International Nuclear Information System (INIS)

    Petti, D.A.; Smolik, G.R.; Anderl, R.A.

    2000-01-01

    One safety concern surrounding beryllium as a plasma-facing material in a water-cooled Tokamak is steam interactions with hot beryllium and the production of significant quantities of hydrogen. We have tested several different product forms of Be with different densities and levels of porosity. Oxidation kinetics has been determined by measurements of hydrogen release with a mass spectrometer, volumetric measurements of the product gas and weight change of the sample. We discuss and compare with the literature the fundamental mechanisms and kinetics controlling the oxidation of Be in steam. Fully dense beryllium exhibits parabolic, linear and accelerating modes of oxidation as temperature increases from 450 deg. C to 1200 deg. C. The oxidation mechanisms and temperature trends are similar for other product forms. Oxidation rates are higher, however, when processing or annealing significantly increases the extent of interconnected porosity and consequently the effective surface area. The effective surface area as measured by BET surface analyses is a key parameter when comparing oxidation rates

  14. Test Operations Procedure (TOP) 08-2-188 Chemical Point Detector Vapor Testing

    Science.gov (United States)

    2018-04-27

    Final 3. DATES COVERED (From - To) 4. TITLE AND SUBTITLE Test Operations Procedure (TOP) 08-2-188 Chemical Point Detector Vapor Testing 5a. CONTRACT...NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT NUMBER 5e. TASK NUMBER 5f. WORK UNIT NUMBER 7. PERFORMING...ORGANIZATION NAME(S) AND ADDRESS(ES) US Army Dugway Proving Ground West Desert Test Center (TEDT-DPW) Dugway, UT 84022-5000 8. PERFORMING ORGANIZATION

  15. Nanoscale multilayered and porous carbide interphases prepared by pressure-pulsed reactive chemical vapor deposition for ceramic matrix composites

    International Nuclear Information System (INIS)

    Jacques, S.; Jouanny, I.; Ledain, O.; Maillé, L.; Weisbecker, P.

    2013-01-01

    In Ceramic Matrix Composites (CMCs) reinforced by continuous fibers, a good toughness is achieved by adding a thin film called “interphase” between the fiber and the brittle matrix, which acts as a mechanical fuse by deflecting the matrix cracks. Pyrocarbon (PyC), with or without carbide sub-layers, is typically the material of choice to fulfill this role. The aim of this work was to study PyC-free nanoscale multilayered carbide coatings as interphases for CMCs. Nanoscale multilayered (SiC–TiC) n interphases were deposited by pressure-Pulsed Chemical Vapor Deposition (P-CVD) on single filament Hi-Nicalon fibers and embedded in a SiC matrix sheath. The thicknesses of the carbide interphase sub-layers could be made as low as a few nanometers as evidenced by scanning and transmission electron microscopy. By using the P-ReactiveCVD method (P-RCVD), in which the TiC growth involves consumption of SiC, it was not only possible to obtain multilayered (SiC–TiC) n films but also TiC films with a porous multilayered microstructure as a result of the Kirkendall effect. The porosity in the TiC sequences was found to be enhanced when some PyC was added to SiC prior to total RCVD consumption. Because the porosity volume fraction was still not high enough, the role of mechanical fuse of the interphases could not be evidenced from the tensile curves, which remained fully linear even when chemical attack of the fiber surface was avoided.

  16. Nanoscale multilayered and porous carbide interphases prepared by pressure-pulsed reactive chemical vapor deposition for ceramic matrix composites

    Science.gov (United States)

    Jacques, S.; Jouanny, I.; Ledain, O.; Maillé, L.; Weisbecker, P.

    2013-06-01

    In Ceramic Matrix Composites (CMCs) reinforced by continuous fibers, a good toughness is achieved by adding a thin film called "interphase" between the fiber and the brittle matrix, which acts as a mechanical fuse by deflecting the matrix cracks. Pyrocarbon (PyC), with or without carbide sub-layers, is typically the material of choice to fulfill this role. The aim of this work was to study PyC-free nanoscale multilayered carbide coatings as interphases for CMCs. Nanoscale multilayered (SiC-TiC)n interphases were deposited by pressure-Pulsed Chemical Vapor Deposition (P-CVD) on single filament Hi-Nicalon fibers and embedded in a SiC matrix sheath. The thicknesses of the carbide interphase sub-layers could be made as low as a few nanometers as evidenced by scanning and transmission electron microscopy. By using the P-ReactiveCVD method (P-RCVD), in which the TiC growth involves consumption of SiC, it was not only possible to obtain multilayered (SiC-TiC)n films but also TiC films with a porous multilayered microstructure as a result of the Kirkendall effect. The porosity in the TiC sequences was found to be enhanced when some PyC was added to SiC prior to total RCVD consumption. Because the porosity volume fraction was still not high enough, the role of mechanical fuse of the interphases could not be evidenced from the tensile curves, which remained fully linear even when chemical attack of the fiber surface was avoided.

  17. A test on reactive force fields for the study of silica dimerization reactions

    Energy Technology Data Exchange (ETDEWEB)

    Moqadam, Mahmoud; Riccardi, Enrico; Trinh, Thuat T.; Åstrand, Per-Olof; Erp, Titus S. van, E-mail: titus.van.erp@ntnu.no [Department of Chemistry, Norwegian University of Science and Technology (NTNU), Høgskoleringen 5, Realfagbygget D3-117, 7491 Trondheim (Norway)

    2015-11-14

    We studied silica dimerization reactions in the gas and aqueous phase by density functional theory (DFT) and reactive force fields based on two parameterizations of ReaxFF. For each method (both ReaxFF force fields and DFT), we performed constrained geometry optimizations, which were subsequently evaluated in single point energy calculations using the other two methods. Standard fitting procedures typically compare the force field energies and geometries with those from quantum mechanical data after a geometry optimization. The initial configurations for the force field optimization are usually the minimum energy structures of the ab initio database. Hence, the ab initio method dictates which structures are being examined and force field parameters are being adjusted in order to minimize the differences with the ab initio data. As a result, this approach will not exclude the possibility that the force field predicts stable geometries or low transition states which are realistically very high in energy and, therefore, never considered by the ab initio method. Our analysis reveals the existence of such unphysical geometries even at unreactive conditions where the distance between the reactants is large. To test the effect of these discrepancies, we launched molecular dynamics simulations using DFT and ReaxFF and observed spurious reactions for both ReaxFF force fields. Our results suggest that the standard procedures for parameter fitting need to be improved by a mutual comparative method.

  18. Mineralogy, geochemistry and expansion testing of an alkali-reactive basalt from western Anatolia, Turkey

    International Nuclear Information System (INIS)

    Copuroglu, Oguzhan; Andic-Cakir, Ozge; Broekmans, Maarten A.T.M.; Kuehnel, Radko

    2009-01-01

    In this paper, the alkali-silica reaction performance of a basalt rock from western Anatolia, Turkey is reported. It is observed that the rock causes severe gel formation in the concrete microbar test. It appears that the main source of expansion is the reactive glassy phase of the basalt matrix having approximately 70% of SiO 2 . The study presents the microstructural characteristics of unreacted and reacted basalt aggregate by optical and electron microscopy and discusses the possible reaction mechanism. Microstructural analysis revealed that the dissolution of silica is overwhelming in the matrix of the basalt and it eventually generates four consequences: (1) Formation of alkali-silica reaction gel at the aggregate perimeter, (2) increased porosity and permeability of the basalt matrix, (3) reduction of mechanical properties of the aggregate and (4) additional gel formation within the aggregate. It is concluded that the basalt rock is highly prone to alkali-silica reaction. As an aggregate, this rock is not suitable for concrete production.

  19. Mineralogy, geochemistry and expansion testing of an alkali-reactive basalt from western Anatolia, Turkey

    Energy Technology Data Exchange (ETDEWEB)

    Copuroglu, Oguzhan, E-mail: O.Copuroglu@CiTG.TUDelft.NL [Delft University of Technology, Faculty of CiTG, Materials and Environment, Stevinweg 1, 2628CN, Delft (Netherlands); Andic-Cakir, Ozge [Ege University, Civil Engineering Dept., 35100 Bornova, Izmir (Turkey); Broekmans, Maarten A.T.M. [Geological Survey of Norway, Dept. of Mineral Characterization, N-7491 Trondheim (Norway); Kuehnel, Radko [Burgemeester Merkusstraat 5, 2645 NJ, Delfgauw (Netherlands)

    2009-07-15

    In this paper, the alkali-silica reaction performance of a basalt rock from western Anatolia, Turkey is reported. It is observed that the rock causes severe gel formation in the concrete microbar test. It appears that the main source of expansion is the reactive glassy phase of the basalt matrix having approximately 70% of SiO{sub 2}. The study presents the microstructural characteristics of unreacted and reacted basalt aggregate by optical and electron microscopy and discusses the possible reaction mechanism. Microstructural analysis revealed that the dissolution of silica is overwhelming in the matrix of the basalt and it eventually generates four consequences: (1) Formation of alkali-silica reaction gel at the aggregate perimeter, (2) increased porosity and permeability of the basalt matrix, (3) reduction of mechanical properties of the aggregate and (4) additional gel formation within the aggregate. It is concluded that the basalt rock is highly prone to alkali-silica reaction. As an aggregate, this rock is not suitable for concrete production.

  20. Cerebral vasomotor reactivity and apnea test in symptomatic and asymptomatic high-grade carotid stenosis

    Directory of Open Access Journals (Sweden)

    Lučić-Prokin Aleksandra

    2015-01-01

    Full Text Available Introduction. Cerebral vasomotor reactivity (VMR represents an autoregulatory response of the arterial trunks on the specific vasoactive stimuli, most commonly CO2. Objective. The aim of this retrospective study was to compare VMR in high-grade symptomatic (SCAS and asymptomatic carotid stenosis (ACAS, using the apnea test to evaluate the hemodynamic status. Methods. The study included 50 patients who were hospitalized at the neurology and vascular surgery departments as part of preparation for carotid endarterectomy. We evaluated VMR by calculating the breath holding index (BHI in 34 patients with SCAS and 16 patients with ACAS, with isolated high-grade carotid stenosis. We evaluated the impact of risk factors and collateral circulation on BHI, as well as the correlation between the degree of carotid stenosis and BHI. Results. A pathological BHI was more frequent in the SCAS group (p<0.01. There was no difference in the range of BHI values between the groups, both ipsilaterally and contralaterally. Only male gender was associated with pathological BHI in both groups (p<0.05. Collateral circulation did not exist in over 60% of all subjects. We confirmed a negative correlation between the degree of carotid stenosis and BHI. Conclusion. SCAS and ACAS patients present with different hemodynamics. While ACAS patients have stable hemodynamics, combination of hemodynamic and thromboembolic effects is characteristic of SCAS patients.

  1. Microstructure, chemical states, and mechanical properties of V–C–Co coatings prepared by non-reactive magnetron sputtering

    International Nuclear Information System (INIS)

    Zhang, Xiaojuan; Wang, Bo; Zhan, Zhaolin; Huang, Feng

    2013-01-01

    V–C–Co coatings have been prepared by non-reactive magnetron co-sputtering from VC and Co targets. The microstructure, chemical states, and mechanical properties are examined as a function of Co content in the coatings. The coatings are dense, with columnar growth structures. High resolution transmission electron microscopy (HRTEM) studies identify a nanocomposite microstructure for the 12.4 at.% Co coating, in which ligament-like Co-rich regions partially separate the nanocrystalline VC grains. X-ray photoelectron spectroscopy studies reveal a noticeable charge transfer from Co 2p states to C 1s states. This charge transfer, in addition to the ligament-like Co-rich regions as revealed by HRTEM, points to the formation of a strong Co/VC interface. The nanoindentation hardness of the coatings drops steadily with the Co content, from 29 GPa for pure VC to ∼ 21 GPa for the 12.4 at.% Co coating. Meanwhile, the plasticity characteristic increased from 0.42 to 0.53. - Highlights: • Nanocomposite V–C–Co coatings with strong Co/VC interfaces were formed. • Found nanocrystalline VC grains separated by ∼ 1 nm thin Co-rich ligaments. • A noticeable amount of C-Co bonds between VC and Co is identified. • V–C–Co coatings exhibited a higher plasticity characteristic than VC

  2. Microstructure, chemical states, and mechanical properties of V–C–Co coatings prepared by non-reactive magnetron sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Xiaojuan [Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, Zhejiang 315201 (China); School of Materials Science and Engineering, Kunming University of Science and Technology, Kunming, Yunnan 650000 (China); Wang, Bo [Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, Zhejiang 315201 (China); Zhan, Zhaolin [School of Materials Science and Engineering, Kunming University of Science and Technology, Kunming, Yunnan 650000 (China); Huang, Feng, E-mail: huangfeng@nimte.ac.cn [Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, Zhejiang 315201 (China)

    2013-07-01

    V–C–Co coatings have been prepared by non-reactive magnetron co-sputtering from VC and Co targets. The microstructure, chemical states, and mechanical properties are examined as a function of Co content in the coatings. The coatings are dense, with columnar growth structures. High resolution transmission electron microscopy (HRTEM) studies identify a nanocomposite microstructure for the 12.4 at.% Co coating, in which ligament-like Co-rich regions partially separate the nanocrystalline VC grains. X-ray photoelectron spectroscopy studies reveal a noticeable charge transfer from Co 2p states to C 1s states. This charge transfer, in addition to the ligament-like Co-rich regions as revealed by HRTEM, points to the formation of a strong Co/VC interface. The nanoindentation hardness of the coatings drops steadily with the Co content, from 29 GPa for pure VC to ∼ 21 GPa for the 12.4 at.% Co coating. Meanwhile, the plasticity characteristic increased from 0.42 to 0.53. - Highlights: • Nanocomposite V–C–Co coatings with strong Co/VC interfaces were formed. • Found nanocrystalline VC grains separated by ∼ 1 nm thin Co-rich ligaments. • A noticeable amount of C-Co bonds between VC and Co is identified. • V–C–Co coatings exhibited a higher plasticity characteristic than VC.

  3. Chemical reactivities of the superconducting oxides, YBa2Cu3Oy and BiSrCaCu2Oy

    International Nuclear Information System (INIS)

    Toyama, Hisashi; Mizuno, Noritaka; Misono, Makoto

    1989-01-01

    The chemical reactivities of YBa 2 Cu 3 O y and BiSrCaCu 2 O y with various gases have been studied. It was found that large quantities of NO, CO, and NO 2 were rapidly absorbed (or intercalated) in the bulk of YBa 2 Cu 3 O y (T c : 90 K) at 573 K. The amount absorbed was in the order NO ∼ CO ∼ NO 2 > O 2 ∼ CO 2 > N 2 O ∼ 0. The amount for NO was more than two times the amount of YBa 2 Cu 3 O y in molar ratio and elongation by about 0.2 angstrom along c-axis was observed. NO absorbed was almost completely recovered as NO by the evacuation at 773 K. This absorption-desorption cycle proceeded reversively. The electronic resistivity at 573 K of YBa 2 Cu 3 O y increased upon the NO absorption and was restored by the evacuation at 773 K. CO was also absorbed rapidly accompanied by evolution of CO 2 . BiSrCaCu 2 O y did not absorb either NO or CO

  4. Influence of crystal defects on the chemical reactivity of recoil atoms in oxygen-containing chromium compounds

    International Nuclear Information System (INIS)

    Costea, T.

    1969-01-01

    The influence of crystal defects on the chemical reactivity of recoil atoms produced by the reaction 50 Cr (n,γ) 51 Cr in oxygen-containing chromium compounds has been studied. Three methods have been used to introduce the defects: doping (K 2 CrO 4 doped with BaCrO 4 ), irradiation by ionizing radiation (K 2 CrO 4 irradiated in the presence of Li 2 CO 3 ) and non-stoichiometry (the semi-conducting oxides of the CrO 3 -Cr 2 O 3 series). The thermal annealing kinetics of the irradiated samples have been determined, and the activation energy has been calculated. In all cases it has been observed that there is a decrease in the activation energy for thermal annealing in the presence of the defects. In order to explain the annealing process, an electronic mechanism has been proposed based on the interaction between the recoil species and the charge-carriers (holes or electrons). (author) [fr

  5. Quantum chemical study of the structure, spectroscopy and reactivity of NO+.(H2O) n=1-5 clusters.

    Science.gov (United States)

    Linton, Kirsty A; Wright, Timothy G; Besley, Nicholas A

    2018-03-13

    Quantum chemical methods including Møller-Plesset perturbation (MP2) theory and density functional theory (DFT) have been used to study the structure, spectroscopy and reactivity of NO + (H 2 O) n =1-5 clusters. MP2/6-311++G** calculations are shown to describe the structure and spectroscopy of the clusters well. DFT calculations with exchange-correlation functionals with a low fraction of Hartree-Fock exchange give a binding energy of NO + (H 2 O) that is too high and incorrectly predict the lowest energy structure of NO + (H 2 O) 2 , and this error may be associated with a delocalization of charge onto the water molecule directly binding to NO + Ab initio molecular dynamics (AIMD) simulations were performed to study the NO + (H 2 O) 5 [Formula: see text] H + (H 2 O) 4 + HONO reaction to investigate the formation of HONO from NO + (H 2 O) 5 Whether an intracluster reaction to form HONO is observed depends on the level of electronic structure theory used. Of note is that methods that accurately describe the relative energies of the product and reactant clusters did not show reactions on the timescales studied. This suggests that in the upper atmosphere the reaction may occur owing to the energy present in the NO + (H 2 O) 5 complex following its formation.This article is part of the theme issue 'Modern theoretical chemistry'. © 2018 The Author(s).

  6. Development and reactivity tests of Ce-Zr-based Claus catalysts for coal gas cleanup

    Energy Technology Data Exchange (ETDEWEB)

    No-Kuk Park; Dong Cheul Han; Gi Bo Han; Si Ok Ryu; Tae Jin Lee; Ki Jun Yoon [Yeungnam University, Gyeongbuk (Republic of Korea). National Research Laboratory, School of Chemical Engineering and Technology

    2007-09-15

    Claus reaction (2H{sub 2}S + SO{sub 2} {leftrightarrow} 3/nS{sub n} + 2H{sub 2}O) was used to clean the gasified coal gas and the reactivity of several metal oxide-based catalysts on Claus reaction was investigated at various operating conditions. In order to convert H{sub 2}S contained in the gasified coal gas to elemental sulfur during Claus reaction, the catalysts having the high activity under the highly reducing condition with the moisture should be developed. CeO{sub 2}, ZrO{sub 2}, and Ce{sub 1-x}Zr{sub x}O{sub 2} catalysts were prepared for Claus reaction and their reactivity changes due to the existence of the reducing gases and H{sub 2}O in the fuel gas was investigated in this study. The Ce-based catalysts shows that their activity was deteriorated by the reduction of the catalyst due to the reducing gases at higher than 220{sup o}C. Meanwhile, the effect of the reducing gases on the catalytic activity was not considerable at low temperature. The activities of all three catalysts were degraded on the condition that the moisture existed in the test gas. Specifically, the Ce-based catalysts were remarkably deactivated by their sulfation. The Ce-Zr-based catalyst had a high catalytic activity when the reducing gases and the moisture co-existed in the simulated fuel gas. The deactivation of the Ce-Zr-based catalyst was not observed in this study. The lattice oxygen of the Ce-based catalyst was used for the oxidation of H{sub 2}S and the lattice oxygen vacancy on the catalyst was contributed to the reduction of SO{sub 2}. ZrO{sub 2} added to the Ce-Zr-based catalyst improved the redox properties of the catalyst in Claus reaction by increasing the mobility of the lattice oxygen of CeO{sub 2}. 21 refs., 14 figs.

  7. Bias-Free Chemically Diverse Test Sets from Machine Learning.

    Science.gov (United States)

    Swann, Ellen T; Fernandez, Michael; Coote, Michelle L; Barnard, Amanda S

    2017-08-14

    Current benchmarking methods in quantum chemistry rely on databases that are built using a chemist's intuition. It is not fully understood how diverse or representative these databases truly are. Multivariate statistical techniques like archetypal analysis and K-means clustering have previously been used to summarize large sets of nanoparticles however molecules are more diverse and not as easily characterized by descriptors. In this work, we compare three sets of descriptors based on the one-, two-, and three-dimensional structure of a molecule. Using data from the NIST Computational Chemistry Comparison and Benchmark Database and machine learning techniques, we demonstrate the functional relationship between these structural descriptors and the electronic energy of molecules. Archetypes and prototypes found with topological or Coulomb matrix descriptors can be used to identify smaller, statistically significant test sets that better capture the diversity of chemical space. We apply this same method to find a diverse subset of organic molecules to demonstrate how the methods can easily be reapplied to individual research projects. Finally, we use our bias-free test sets to assess the performance of density functional theory and quantum Monte Carlo methods.

  8. Can water quality of tubewells be assessed without chemical testing?

    Science.gov (United States)

    Hoque, Mohammad A.; Butler, Adrian P.

    2016-04-01

    Arsenic is one of the major pollutants found in aquifers on a global scale. The screening of tubewells for arsenic has helped many people to avoid drinking from highly polluted wells in the Bengal Delta (West Bengal and Bangladesh). However, there are still many millions of tubewells in Bangladesh yet to be tested, and a substantial proportion of these are likely to contain excessive arsenic. Due to the level of poverty and lack of infrastructure, it is unlikely that the rest of the tubewells will be tested quickly. However, water quality assessment without needing a chemical testing may be helpful in this case. Studies have found that qualitative factors, such as staining in the tubewell basement and/or on utensils, can indicate subsurface geology and water quality. The science behind this staining is well established, red staining is associated with iron reduction leading to release of arsenic whilst black staining is associated with manganese reduction (any release of arsenic due to manganese reduction is sorbed back on the, yet to be reduced, iron), whereas mixed staining may indicate overlapping manganese and iron reduction at the tubewell screen. Reduction is not uniform everywhere and hence chemical water quality including dissolved arsenic varies from place to place. This is why coupling existing tubewell arsenic information with user derived staining data could be useful in predicting the arsenic status at a particular site. Using well location, depth, along with colour of staining, an assessment of both good (nutrients) and bad (toxins and pathogens) substances in the tubewell could be provided. Social-network technology, combined with increasing use of smartphones, provides a powerful opportunity for both sharing and providing feedback to the user. Here we outline how a simple digital application can couple the reception both qualitative and quantitative tubewell data into a centralised interactive database and provide manipulated feedback to an

  9. Contact allergy to popular perfumes; assessed by patch test, use test and chemical analysis.

    Science.gov (United States)

    Johansen, J D; Rastogi, S C; Menné, T

    1996-09-01

    The frequency of contact allergy to the 10 best-selling women's perfumes was studied in 335 consecutive female eczema patients by patch testing. The diagnostic ability of the fragrance mix, in relation to these products, was evaluated. Of eczema patients, 6.9% had a positive patch test to one or more of the perfumes, and 56.5% of these had a concurrent positive reaction to the fragrance mix. Hence, testing with the patients' own cosmetics is a significant part of diagnosing perfume allergy. The clinical relevance of the patch-test reactions to the commercial perfumes was equal to that of the fragrance mix, as judged from the patient's history and use testing with one of the perfumes. At least three of the chemically defined sensitizers in the fragrance mix were detected in all the perfumes by gas chromatography-mass spectrometry, which indicates that the fragrance mix is a good imitation of actual exposure.

  10. Contact allergy to popular perfumes; assessed by patch test, use test and chemical analysis

    DEFF Research Database (Denmark)

    Johansen, J D; Rastogi, Suresh Chandra; Menné, T

    1996-01-01

    The frequency of contact allergy to the 10 best-selling women's perfumes was studied in 335 consecutive female eczema patients by patch testing. The diagnostic ability of the fragrance mix, in relation to these products, was evaluated. Of eczema patients, 6.9% had a positive patch test to one...... or more of the perfumes, and 56.5% of these had a concurrent positive reaction to the fragrance mix. Hence, testing with the patients' own cosmetics is a significant part of diagnosing perfume allergy. The clinical relevance of the patch-test reactions to the commercial perfumes was equal...... to that of the fragrance mix, as judged from the patient's history and use testing with one of the perfumes. At least three of the chemically defined sensitizers in the fragrance mix were detected in all the perfumes by gas chromatography-mass spectrometry, which indicates that the fragrance mix is a good imitation...

  11. Chemical Reactivity of Isoproturon, Diuron, Linuron, and Chlorotoluron Herbicides in Aqueous Phase: A Theoretical Quantum Study Employing Global and Local Reactivity Descriptors

    Directory of Open Access Journals (Sweden)

    Luis Humberto Mendoza-Huizar

    2015-01-01

    Full Text Available We have calculated global and local DFT reactivity descriptors for isoproturon, diuron, linuron, and chlorotoluron herbicides at the MP2/6-311++G(2d,2p level of theory. The results suggest that, in aqueous conditions, chlorotoluron, linuron, and diuron herbicides may be degraded by elimination of urea moiety through electrophilic attacks. On the other hand, electrophilic, nucleophilic, and free radical attacks on isoproturon may cause the elimination of isopropyl fragment.

  12. Combinatorial QSAR modeling of chemical toxicants tested against Tetrahymena pyriformis.

    Science.gov (United States)

    Zhu, Hao; Tropsha, Alexander; Fourches, Denis; Varnek, Alexandre; Papa, Ester; Gramatica, Paola; Oberg, Tomas; Dao, Phuong; Cherkasov, Artem; Tetko, Igor V

    2008-04-01

    Selecting most rigorous quantitative structure-activity relationship (QSAR) approaches is of great importance in the development of robust and predictive models of chemical toxicity. To address this issue in a systematic way, we have formed an international virtual collaboratory consisting of six independent groups with shared interests in computational chemical toxicology. We have compiled an aqueous toxicity data set containing 983 unique compounds tested in the same laboratory over a decade against Tetrahymena pyriformis. A modeling set including 644 compounds was selected randomly from the original set and distributed to all groups that used their own QSAR tools for model development. The remaining 339 compounds in the original set (external set I) as well as 110 additional compounds (external set II) published recently by the same laboratory (after this computational study was already in progress) were used as two independent validation sets to assess the external predictive power of individual models. In total, our virtual collaboratory has developed 15 different types of QSAR models of aquatic toxicity for the training set. The internal prediction accuracy for the modeling set ranged from 0.76 to 0.93 as measured by the leave-one-out cross-validation correlation coefficient ( Q abs2). The prediction accuracy for the external validation sets I and II ranged from 0.71 to 0.85 (linear regression coefficient R absI2) and from 0.38 to 0.83 (linear regression coefficient R absII2), respectively. The use of an applicability domain threshold implemented in most models generally improved the external prediction accuracy but at the same time led to a decrease in chemical space coverage. Finally, several consensus models were developed by averaging the predicted aquatic toxicity for every compound using all 15 models, with or without taking into account their respective applicability domains. We find that consensus models afford higher prediction accuracy for the

  13. VHTRC experiment for verification test of H{infinity} reactivity estimation method

    Energy Technology Data Exchange (ETDEWEB)

    Fujii, Yoshio; Suzuki, Katsuo; Akino, Fujiyoshi; Yamane, Tsuyoshi; Fujisaki, Shingo; Takeuchi, Motoyoshi; Ono, Toshihiko [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1996-02-01

    This experiment was performed at VHTRC to acquire the data for verifying the H{infinity} reactivity estimation method. In this report, the experimental method, the measuring circuits and data processing softwares are described in details. (author).

  14. Permeation Testing of Materials With Chemical Agents or Simulants (Swatch Testing)

    Science.gov (United States)

    2013-08-05

    nerve agents, sarin (GB), soman (GD), and persistent nerve agent (VX). These procedures can also be applied to toxic industrial chemicals (TICs...garment, cap, clothing liner, mask, glove, footwear , etc. The swatch should be selected to be representative of the area of the material to be tested...solvent and the extract analyzed. This reduces the sensitivity but obviates problems arising from one-shot thermal desorption. c. NRT and real

  15. OECD Guidelines for the Testing of Chemicals, Test No. 226: Predatory mite (Hypoaspis (Geolaelaps) aculeifer) reproduction test in soil

    DEFF Research Database (Denmark)

    Römbke, L. Becker, B. Dark, Th. Moser, N. Halsall, W. Powley, A. Ruf, C. Scholer, E. Smit, P. Wege, N. Zenz m.fl., J.; Krogh, Paul Henning

    2008-01-01

    This Test Guideline describes a method to assess the effects of chemical substances in soil on the reproductive output of the soil mite species Hypoaspis (Geolaelaps) aculeifer Canestrini (Acari: Laelapidae). It can be used for water soluble or insoluble substances, but not with volatile substances...... replicates for each test concentrations and six to eight control replicates, of 10 animals each, are recommended. At 20 oC, the test lasts 14 days after introducing the females, which usually allows the control offspring to reach the deutonymph stage. The number of surviving females (mortality ...% for a valid test) and the number of juveniles per test vessel (at least 50 for a valid test) are determined. The fecundity of the mites exposed to the test substance is compared to that of controls in order to determine the ECx (e.g. EC10, EC50) or the No Observed Effect Concentration (NOEC). Any observed...

  16. Real rock-microfluidic flow cell: A test bed for real-time in situ analysis of flow, transport, and reaction in a subsurface reactive transport environment.

    Science.gov (United States)

    Singh, Rajveer; Sivaguru, Mayandi; Fried, Glenn A; Fouke, Bruce W; Sanford, Robert A; Carrera, Martin; Werth, Charles J

    2017-09-01

    Physical, chemical, and biological interactions between groundwater and sedimentary rock directly control the fundamental subsurface properties such as porosity, permeability, and flow. This is true for a variety of subsurface scenarios, ranging from shallow groundwater aquifers to deeply buried hydrocarbon reservoirs. Microfluidic flow cells are now commonly being used to study these processes at the pore scale in simplified pore structures meant to mimic subsurface reservoirs. However, these micromodels are typically fabricated from glass, silicon, or polydimethylsiloxane (PDMS), and are therefore incapable of replicating the geochemical reactivity and complex three-dimensional pore networks present in subsurface lithologies. To address these limitations, we developed a new microfluidic experimental test bed, herein called the Real Rock-Microfluidic Flow Cell (RR-MFC). A porous 500μm-thick real rock sample of the Clair Group sandstone from a subsurface hydrocarbon reservoir of the North Sea was prepared and mounted inside a PDMS microfluidic channel, creating a dynamic flow-through experimental platform for real-time tracking of subsurface reactive transport. Transmitted and reflected microscopy, cathodoluminescence microscopy, Raman spectroscopy, and confocal laser microscopy techniques were used to (1) determine the mineralogy, geochemistry, and pore networks within the sandstone inserted in the RR-MFC, (2) analyze non-reactive tracer breakthrough in two- and (depth-limited) three-dimensions, and (3) characterize multiphase flow. The RR-MFC is the first microfluidic experimental platform that allows direct visualization of flow and transport in the pore space of a real subsurface reservoir rock sample, and holds potential to advance our understandings of reactive transport and other subsurface processes relevant to pollutant transport and cleanup in groundwater, as well as energy recovery. Copyright © 2017 Elsevier B.V. All rights reserved.

  17. Efficiency of a Malaria Reactive Test-and-Treat Program in Southern Zambia: A Prospective, Observational Study.

    Science.gov (United States)

    Deutsch-Feldman, Molly; Hamapumbu, Harry; Lubinda, Jailos; Musonda, Michael; Katowa, Ben; Searle, Kelly M; Kobayashi, Tamaki; Shields, Timothy M; Stevenson, Jennifer C; Thuma, Philip E; Moss, William J; For The Southern Africa International Centers Of Excellence For Malaria Research

    2018-05-01

    To improve malaria surveillance and achieve elimination, the Zambian National Malaria Elimination Program implemented a reactive test-and-treat program in Southern Province in 2013 in which individuals with rapid diagnostic test (RDT)-confirmed malaria are followed-up at their home within 1 week of diagnosis. Individuals present at the index case household and those residing within 140 m of the index case are tested with an RDT and treated with artemether-lumefantrine if positive. This study evaluated the efficiency of this reactive test-and-treat strategy by characterizing infected individuals missed by the RDT and the current screening radius. The radius was expanded to 250 m, and a quantitative polymerase chain reaction (qPCR) test was performed on dried blood spot specimens. From January 2015 through March 2016, 145 index cases were identified at health centers and health posts. A total of 3,333 individuals residing in 525 households were screened. Excluding index cases, the parasite prevalence was 1.1% by RDT (33 positives of 3,016 participants) and 2.4% by qPCR (73 positives of 3,016 participants). Of the qPCR-positive cases, 62% of 73 individuals tested negative by RDT. Approximately half of the infected individuals resided within the index case household (58% of RDT-positive individuals and 48% of qPCR-positive individuals). The low sensitivity of the RDT and the high proportion of secondary cases within the index case household decreased the efficiency of this reactive test-and-treat strategy. Reactive focal drug administration in index case households would be a more efficient approach to treating infected individuals associated with a symptomatic case.

  18. House dust bioactivities predict skin prick test reactivity for children with high risk of allergy.

    Science.gov (United States)

    Kim, Haejin; Tse, Kevin; Levin, Linda; Bernstein, David; Reponen, Tiina; LeMasters, Grace; Lummus, Zana; Horner, Anthony A

    2012-06-01

    Although evidence suggests that ambient exposures to endotoxin and other immunostimulants during early life influence allergic risk, efforts to understand this host-environment relationship have been hampered by a paucity of relevant assays. These investigations determined whether parameters of house dust extract (HDE) bioactivity were predictive of allergen skin prick test (SPT) reactivity for infants at high risk of allergy participating in the Cincinnati Childhood Allergy and Air Pollution Study (CCAAPS). We conducted a nested case-control study, selecting 99 CCAAPS children who had positive SPT results to at least 1 aeroallergen at age 3 years and 101 subjects with negative SPT results. HDEs were prepared from dust samples collected from the subjects' homes at age 1 year. Murine splenocytes and bone marrow-derived dendritic cells were incubated with HDEs, and supernatant cytokine concentrations were determined by means of ELISA. Alternatively, bone marrow-derived dendritic cells were preincubated with HDEs, and then LPS-induced IL-6 responses were assessed. HDE endotoxin levels were determined by using the limulus amebocyte lysate assay. HDEs derived from the homes of children with positive (cases) and negative (control subjects) SPT results had similar bioactivities. However, when cases were considered in isolation, HDEs with higher levels of bioactivity were significantly associated with children who had lower numbers of positive SPT results. Analogous statistical analyses did not identify any association between HDE endotoxin levels and the aeroallergen sensitization profiles of children included in this study. HDE immunostimulatory activities predicted the aeroallergen sensitization status of CCAAPS subjects better than HDE endotoxin levels. These results provide the first published evidence that HDE bioassays have clinical relevance in predicting atopic risk. Copyright © 2012 American Academy of Allergy, Asthma & Immunology. Published by Mosby, Inc. All

  19. 75 FR 8575 - Testing of Certain High Production Volume Chemicals; Third Group of Chemicals

    Science.gov (United States)

    2010-02-25

    ...: Beilstein Database, CRC Handbook of Chemistry and Physics, Hawley's Condensed Chemical Dictionary, Illustrated Handbooks of Physical- Chemical Properties and Environmental Fate for Organic Chemicals, Merck... Coefficient: Method A (40 CFR 799.6755--shake flask). Method B (ASTM E 1147-92(2005)--liquid chromatography...

  20. The hydraulic properties of fracture zones and tracer tests with non-reactive elements in Studsvik

    International Nuclear Information System (INIS)

    Klockars, C.-E.; Persson, O.; Landstroem, O.

    1982-04-01

    Tracer technique was applied in a rock formation within the Studsvik Energiteknik area in order to study hydrodynamic properties of discrete fracture zones between boreholes. The two hole method was applied in these studies; a nonreactive tracer is injected in one hole into a fracture zone which is in hydraulic contact with a central pump hole (observation hole). Hydraulic tests and TV inspection were carried out in the fracture zones. Chemical composition of the groundwater was determined. In summary, the following hydraulic properties were found for the fracture zones between the boreholes B1N-B6N and B5N-B6N respectively, under the prevailing conditions: 1) The fracture zones studied consists of a number of transport pathways with different mean transit times, varying from 100 to 1200 hours. 2) The fracture zone between boreholes B1N and B6N has a mean hydraulic conductivity of 6-7 x 10 -5 m/s and the fracture zone between boreholes B5N and B6N, 2 x 10 -4 m/s. 3) The kinematic porosity of the fracture zones studied, calculated as the ratio between the hydraulic conductivity of the rock mass and that of the fracture zone, is 2 x 10 -3 and 5 x 10 -3 , respectively. 4) The roughness factor β, which expresses the ratio between measured and theoretically calculated (plane-parallel) fracture conductivity for the fracture zones studied, is approximately 0.04 and 0.06, respectively. 5) Dispersivity for the flow channels within the fracture zones is of the order of 0.3-0.8 m. 6) The groundwater encountered is a nearly neutral, probably reducing, Na-Ca-HCO 3 water. The results of the tracer tests reveal the following: I-131 is a suitable nonreactive tracer for the test area. A test with simultaneous injection of I-131 and T (tritium) gave comparable breakthrough curves. (Author)

  1. Testing single extraction methods and in vitro tests to assess the geochemical reactivity and human bioaccessibility of silver in urban soils amended with silver nanoparticles

    NARCIS (Netherlands)

    Cruz, N.; Rodrigues, S.M.; Tavares, D.; Monteiro, R.J.R.; Carvalho, L.; Trindade, T.; Duarte, A.C.; Pereira, E.; Romkens, Paul

    2015-01-01

    To assess if the geochemical reactivity and human bioaccessibility of silver nanoparticles (AgNPs) in soils can be determined by routine soil tests commonly applied to other metals in soil, colloidal Ag was introduced to five pots containing urban soils (equivalent to 6.8mgAgkg-1

  2. Skin sensitization potency and cross-reactivity of p-phenylenediamine and its derivatives evaluated by non-radioactive murine local lymph node assay and guinea-pig maximization test.

    Science.gov (United States)

    Yamano, Tetsuo; Shimizu, Mitsuru

    2009-04-01

    p-Phenylenediamine (PPD)-related chemicals have been used as antioxidants in rubber products, and many cases of contact dermatitis caused by these chemicals have been reported. The aim of this study was to investigate relative sensitizing potency and cross-reactivity among PPD derivatives. Five PPD derivatives, p-aminodiphenylamine (PADPA), N,N'-diphenyl-p-phenylenediamine (DPPD), N-isopropyl-N'-phenyl-p-phenylenediamine (IPPD), N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine (DMBPPD), N-(1-methylheptyl)-N'-phenyl-p-phenylenediamine (MHPPD), and the core chemical PPD were evaluated for their sensitizing potency and cross-reactivity using the non-radioactive murine local lymph node assay (LLNA) and the guinea-pig maximization test (GPMT). PPD and all the derivatives were identified as primary sensitizers in both tests. The order of potency in the LLNA was as follows: IPPD and PADPA > PPD > DMBPPD and MHPPD > DPPD. In the GPMT, all six groups of animals sensitized with one of these chemicals cross-reacted to four other derivatives. Specifically, the five groups that have a common basic PADPA structure, that is PADPA, DPPD, IPPD, DMBPPD, and MHPPD, all reacted to each other at almost the same scores, while none of them reacted to PPD. The cross-reactivity profile found in the study was to some extent different from that in previous human data, where distinction between cross-reaction and concomitant primary sensitization is not always clear.

  3. Developing ecotoxicological testing procedures for chemicals in soils

    International Nuclear Information System (INIS)

    Scheunert, I.; Doerfler, U.; Quast, I.; Schroll, R.; Topp, E.; Wolf, E.; Korte, F.

    1989-01-01

    The work deals with the determination of adsorption coefficients of volatile environmental chemicals, of volatilization rates (example: Lindane), biomineralization rates, total balances, and uptake into higher plants, further with the correlation of the uptake of chemicals by plants with physico-chemical and structural mass characteristics, and field experiments with lysimeters using labelled carbon 14 compounds for validation of the results obtained under laboratory conditions. - The devices for determination of adsorption coefficients and of volatilization rates of chemicals from soil and plant surfaces, as well as the closed experimental setup with controlled air throughput for billing labelled carbon 14 chemicals in the soil/plant system are described. The mass balance of the adsorption of volatile labelled carbon 14 chemicals in an alfisol, the volatilization of Lindane from the surface of a sandy soil, the concentration of hexachlorbenzene in different parts of plants, the uptake pathways of organic chemicals in higher plants and their corelation with mass properties, as well as the correlation between bioconcentration factors of chemicals in barley after application into the soil and physico-chemical and structural mass parameters are investigated and indicated in the form of tables and diagrams. (HK) [de

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

    Science.gov (United States)

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

    2017-10-01

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

  5. A coupling alternative to reactive transport simulations for long-term prediction of chemical reactions in heterogeneous CO2 storage systems

    Directory of Open Access Journals (Sweden)

    M. De Lucia

    2015-02-01

    Full Text Available Fully coupled, multi-phase reactive transport simulations of CO2 storage systems can be approximated by a simplified one-way coupling of hydrodynamics and reactive chemistry. The main characteristics of such systems, and hypotheses underlying the proposed alternative coupling, are (i that the presence of CO2 is the only driving force for chemical reactions and (ii that its migration in the reservoir is only marginally affected by immobilisation due to chemical reactions. In the simplified coupling, the exposure time to CO2 of each element of the hydrodynamic grid is estimated by non-reactive simulations and the reaction path of one single batch geochemical model is applied to each grid element during its exposure time. In heterogeneous settings, analytical scaling relationships provide the dependency of velocity and amount of reactions to porosity and gas saturation. The analysis of TOUGHREACT fully coupled reactive transport simulations of CO2 injection in saline aquifer, inspired to the Ketzin pilot site (Germany, both in homogeneous and heterogeneous settings, confirms that the reaction paths predicted by fully coupled simulations in every element of the grid show a high degree of self-similarity. A threshold value for the minimum concentration of dissolved CO2 considered chemically active is shown to mitigate the effects of the discrepancy between dissolved CO2 migration in non-reactive and fully coupled simulations. In real life, the optimal threshold value is unknown and has to be estimated, e.g. by means of 1-D or 2-D simulations, resulting in an uncertainty ultimately due to the process de-coupling. However, such uncertainty is more than acceptable given that the alternative coupling enables using grids of the order of millions of elements, profiting from much better description of heterogeneous reservoirs at a fraction of the calculation time of fully coupled models.

  6. Assessing Chemical Transformation of Reactive, Interfacial Thin Films Made of End-Tethered Poly(2-vinyl-4,4-dimethyl azlactone) (PVDMA) Chains

    Energy Technology Data Exchange (ETDEWEB)

    Aden, Bethany [Univ. of Tennessee, Knoxville, TN (United States). Dept. of Chemistry; Kite, Camille M. [Univ. of Tennessee, Knoxville, TN (United States). Dept. of Chemistry; Hopkins, Benjamin W. [Univ. of Tennessee, Knoxville, TN (United States). Dept. of Chemical and Biomolecular Engineering; Zetterberg, Anna [Univ. of Tennessee, Knoxville, TN (United States). Dept. of Chemical and Biomolecular Engineering; Lokitz, Bradley S. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Center for Nanophase Materials Science (CNMS); Ankner, John Francis [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Spallation Neutron Source (SNS); Kilbey, S. Michael [Univ. of Tennessee, Knoxville, TN (United States). Dept. of Chemistry; Univ. of Tennessee, Knoxville, TN (United States). Dept. of Chemical and Biomolecular Engineering

    2017-01-24

    Designing thin films or surface scaffolds with an appropriate display of chemical functionality is useful for biomedical applications, sensing platforms, adhesives, and barrier coatings. Relationships between the structural characteristics of model thin films based on reactive poly(2-vinyl-4,4-dimethylazlactone) (PVDMA) brushes and the amount and distribution of primary amines used to chemically functionalize the layer in situ are quantitatively detailed via neutron reflectometry and compared with results from ellipsometry. After functionalization, the PVDMA brush thickness increases as a result of the primary amines reacting with the azlactone rings. Both techniques show that the extent of functionalization by small-molecule amines depends on the size of the amine, the grafting density of brush chains and their molecular weight. However, constrained analysis of neutron reflectivity data predicated on that technique’s sensitivity to isotopic substitution and its ability to resolve structure at the nanoscale, shows that the extent of functionalization is not accurately represented by the average extent of functionalization determined from ellipsometric thickness: reactive modification is not uniform, even in modestly dense brushes, except when the penetrant is small. Additionally, there appears to be a loss of PVDMA chains during functionalization, attributed to chain scission resulting from additional stretching brought about by functionalization. These findings provide unprecedented insight into the alteration of surface properties by reactive modification and broadly support efforts to produce tailored surfaces in which properties such as friction, colloidal stability, adhesion, wettability, and biocompatibility can be modulated in situ by chemical modification.

  7. Study of the cross-reactivity of fish allergens based on a questionnaire and blood testing

    Directory of Open Access Journals (Sweden)

    Yukihiro Kobayashi

    2016-07-01

    Conclusions: Most patients with fish allergies displayed allergic symptoms following the intake of various fish species. In addition, fish parvalbumin and collagen were causative factors of fish allergy and were highly cross-reactive fish panallergens. Therefore, current laws should be revised in Japan and South Korea.

  8. Food allergy and cross-reactivity-chickpea as a test case.

    Science.gov (United States)

    Bar-El Dadon, Shimrit; Pascual, Cristina Y; Reifen, Ram

    2014-12-15

    Chickpea has become one of the most abundant crops consumed in the Mediterranean and also in western world. Chickpea allergy is reported in specific geographic areas and is associated with lentil and/or pea allergy. We investigated cross-reactivity between chickpea and pea/lentil/soybean/hazelnut. The IgE-binding profiles of chickpea globulin and pea/lentil/soybean/hazelnut extracts were analyzed by immunoblotting and immunoblot-inhibition studies. Inhibition-assay with pea/lentil completely suppressed IgE-binding to chickpea globulin allergens, while not so in the reciprocal inhibition. Pre-absorption of sera with chickpea globulin caused the disappearance of IgE-binding to protein on an immunoblot of soybean/hazelnut protein extract. These results suggest that cross-reactivity exists between chickpea and pea/lentil/soybean/hazelnut. Chickpea allergy is associated with lentil and/or pea allergy, but evidently may not present independently. This, together with the described asymmetric cross-reactivity and phylogenetic aspects, suggest that chickpea allergy is merely an expression of cross-reactivity, caused by pea and/or lentil as the "primary" allergen. Copyright © 2014 Elsevier Ltd. All rights reserved.

  9. Colour quantitation for chemical spot tests for a controlled substances presumptive test database.

    Science.gov (United States)

    Elkins, Kelly M; Weghorst, Alex C; Quinn, Alicia A; Acharya, Subrata

    2017-02-01

    Crime scene investigators (CSIs) often encounter unknown powders, capsules, tablets, and liquids at crime scenes, many of which are controlled substances. Because most drugs are white powders, however, visual determination of the chemical identity is difficult. Colourimetric tests are a well-established method of presumptive drug identification. Positive tests are often reported differently, however, because two analysts may perceive colour or record colourimetric results in different ways. In addition to perceiving colour differently, it is very common for there to be poor visibility conditions (e.g. rain, darkness) while performing these tests, further obscuring the results. In order to address these concerns and to create uniformity in the reporting of on-site colourimetric test results, this study has evaluated two of the state-of-the-art apps (ColorAssist® and Colorimeter®) for reporting the colour test results quantitatively in red-green-blue (RGB) format. The compiled library database of presumptive test results contains over 3300 data points including over 800 unique drug/test combinations. Variations observed between test replicates, from performing a test on different days, recording with a different device type (e.g. iPod Touch, iPhone models 4, 5c, 5s, or 6), and using different quantities of drug are discussed. Overall, the least variation in Euclidian norm was observed using ColorAssist® with the camera light (25.1±22.1) while the variation between replicates and data recorded using different devices was similar. The resulting library is uploaded to a smartphone application aimed to aid in identifying and interpreting suspected controlled substance evidence. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  10. Enhanced reactivation of UV-irradiated adenovirus 2 in HeLa cells treated with non-mutagenic chemical agents

    Energy Technology Data Exchange (ETDEWEB)

    Piperakis, S.M.; McLennan, A.G. (Liverpool Univ. (UK). Dept. of Biochemistry)

    1985-03-01

    Treatment of HeLa cells with ethanol and sodium arsenite, compounds which are known to elicit the heat-shock response, before infection with UV-irradiated adenovirus 2 has been found to result in the enhanced reactivation of the damaged virus in a manner similar to that obtained by pre-irradiation or heating of the cells. Enhanced reactivation may be the result of the inhibition of DNA synthesis caused by these agents since hydroxyurea also produced a significant enhancement.

  11. Revealing the importance of linkers in K-series oxime reactivators for tabun-inhibited AChE using quantum chemical, docking and SMD studies.

    Science.gov (United States)

    Ghosh, Shibaji; Chandar, Nellore Bhanu; Jana, Kalyanashis; Ganguly, Bishwajit

    2017-08-01

    Inhibition of acetylcholinesterase (AChE) with organophosphorus compounds has a detrimental effect on human life. Oxime K203 seems to be one of the promising reactivators for tabun-inhibited AChE than (K027, K127, and K628). These reactivators differ only in the linker units between the two pyridinium rings. The conformational analyses performed with quantum chemical RHF/6-31G* level for K027, K127, K203 and K628 showed that the minimum energy conformers have different orientations of the active and peripheral pyridinium rings for these reactivator molecules. K203 with (-CH 2 -CH=CH-CH 2 -) linker unit possesses more open conformation compared to the other reactivators. Such orientation of K203 experiences favorable interaction with the surrounding residues of catalytic anionic site (CAS) and peripheral anionic site (PAS) of tabun-inhibited AChE. From the steered molecular dynamics simulations, it has been observed that the oxygen atom of the oxime group of K203 reactivator approaches nearest to the P-atom of the SUN203 (3.75 Å) at lower time scales (less than ~1000 ps) as compared to the other reactivators. K203 experiences less number of hydrophobic interaction with the PAS residues which is suggested to be an important factor for the efficient reactivation process. In addition, K203 crates large number of H-bonding with CAS residues SUN203, Phe295, Tyr337, Phe338 and His447. K203 barely changes its conformation during the SMD simulation process and hence the energy penalty to adopt any other conformation is minimal in this case as compared to the other reactivators. The molecular mechanics and Poisson-Boltzmann surface area binding energies obtained for the interaction of K203 inside the gorge of tabun inhibited AChE is substantially higher (-290.2 kcal/mol) than the corresponding K628 reactivator (-260.4 kcal/mol), which also possess unsaturated aromatic linker unit.

  12. Revealing the importance of linkers in K-series oxime reactivators for tabun-inhibited AChE using quantum chemical, docking and SMD studies

    Science.gov (United States)

    Ghosh, Shibaji; Chandar, Nellore Bhanu; Jana, Kalyanashis; Ganguly, Bishwajit

    2017-08-01

    Inhibition of acetylcholinesterase (AChE) with organophosphorus compounds has a detrimental effect on human life. Oxime K203 seems to be one of the promising reactivators for tabun-inhibited AChE than (K027, K127, and K628). These reactivators differ only in the linker units between the two pyridinium rings. The conformational analyses performed with quantum chemical RHF/6-31G* level for K027, K127, K203 and K628 showed that the minimum energy conformers have different orientations of the active and peripheral pyridinium rings for these reactivator molecules. K203 with (-CH2-CH=CH-CH2-) linker unit possesses more open conformation compared to the other reactivators. Such orientation of K203 experiences favorable interaction with the surrounding residues of catalytic anionic site (CAS) and peripheral anionic site (PAS) of tabun-inhibited AChE. From the steered molecular dynamics simulations, it has been observed that the oxygen atom of the oxime group of K203 reactivator approaches nearest to the P-atom of the SUN203 (3.75 Å) at lower time scales (less than 1000 ps) as compared to the other reactivators. K203 experiences less number of hydrophobic interaction with the PAS residues which is suggested to be an important factor for the efficient reactivation process. In addition, K203 crates large number of H-bonding with CAS residues SUN203, Phe295, Tyr337, Phe338 and His447. K203 barely changes its conformation during the SMD simulation process and hence the energy penalty to adopt any other conformation is minimal in this case as compared to the other reactivators. The molecular mechanics and Poisson-Boltzmann surface area binding energies obtained for the interaction of K203 inside the gorge of tabun inhibited AChE is substantially higher (-290.2 kcal/mol) than the corresponding K628 reactivator (-260.4 kcal/mol), which also possess unsaturated aromatic linker unit.

  13. Chemical pneumonitis and subsequent reactive airways dysfunction syndrome after a single exposure to a household product: a case report

    Directory of Open Access Journals (Sweden)

    Khalid Imran

    2009-11-01

    Full Text Available Abstract Introduction Household products are usually safe to use. Adverse events arising from their use are mostly reported in patients with pre-existing atopy or pulmonary problems and usually only after a prolonged exposure to such products. We report the case of a patient with no prior problems who developed significant side effects from a single exposure to a domestic product. Case presentation A 43-year-old Caucasian American man, previously in good health, used a domestic aerosol product called 'Stand N' Seal "Spray-On" Grout Sealer' in an enclosed room in his house. The product contained n-butyl acetate ( Conclusion A household product may still prove unsafe to use even after it has gone through vigorous testing and approval processes. Even healthy individuals are susceptible to adverse outcomes after a brief exposure. Extra precautions should be taken when using any chemical product at home.

  14. Physiological reactivity in a community sample of sexually aggressive young men: a test of competing hypotheses.

    Science.gov (United States)

    Peterson, Zoë D; Janssen, Erick; Goodrich, David; Heiman, Julia R

    2014-01-01

    Men's sexually aggressive behavior potentially could relate to either physiological hyporeactivity or hyperreactivity, and these two different physiological profiles could be associated with different underlying causes of sexual aggression. Thus, measurement of physiological reactivity could provide insight into mechanisms relevant to the etiology of sexual aggression. The relationship between sexual aggression and physiological reactivity was investigated in 78 community men (38 sexually aggressive and 40 non-aggressive men). In a laboratory protocol, the men were exposed to neutral, negative-affect-inducing, and positive-affect-inducing stimuli. Men's salivary cortisol concentrations and electrodermal activity (EDA) were measured throughout the laboratory procedure. Sexually aggressive men demonstrated (1) lower overall cortisol levels and (2) lower EDA reactivity in some conditions as compared to non-aggressive men. Results of this study were consistent with the idea that men's sexual aggression is associated with physiological hyporeactivity, a physiological profile that has been found to be associated with externalizing behaviors and psychopathic traits. © 2013 Wiley Periodicals, Inc.

  15. Reactivity worth of gas expansion modules (GEMs) in the fast flux test facility

    International Nuclear Information System (INIS)

    Campbell, L.R.; Nelson, J.V.; Burke, T.M.; Rawlins, J.A.; Daughtry, J.W.; Bennett, R.A.

    1986-01-01

    A new passive shutdown device called a gas expansion module (GEM) has been developed at Hanford Engineering Development Laboratory to insert negative reactivity during a primary system loss of flow in a liquid-metal reactor (LMR). A GEM is a hollow removable core component which is sealed at the top and open at the bottom. An argon gas bubble trapped inside the assembly expands when core inlet pressure decreases (caused by a flow reduction) and expels sodium from the assembly. The GEMs are designed so that the level of the liquid-sodium primary system coolant within a GEM is above the top of the core when the primary pumps are operating at full flow and is below the bottom of the core when the primary pumps are off. When a GEM is placed at the boundary of the core and radial reflector, the drop in sodium level increases core neutron leakage and inserts negative reactivity. The results of these measurements confirm the effectiveness of GEMs in adding negative reactivity in loss-of-flow situations. It follows, therefore, that the inherent safety of LMRs, comparable in size to the FFTF, can be enhanced by the use of GEMs

  16. Test plan for Digface Chemical and Radiation Assay System

    International Nuclear Information System (INIS)

    Akers, D.W.

    1993-07-01

    The Digface Chemical and Radiation Assay System (CRAS) Project will develop a sensor using Prompt Gamma Neutron Activation Analysis (PGNAA) that can detect the present of hazardous chemicals and radioactive materials. The CRAS is being designed for in situ assay of closed drums and contaminated soils for gamma-ray emitting radionuclides and hazardous elements. The CRAS is based upon the use of 252 Cf PGNAA with a germanium gamma-ray spectrometer as the analyzer. Tasks being performed include determining detection limits for a number of hazardous chemicals and assessing matrix and transmission effects through soil. Initial analyses suggest that the technique is applicable to a number of hazardous materials such as trichloroethane and carbon tetrachloride

  17. Characterization of the chemical reactivity and nephrotoxicity of N-acetyl-S-(1,2-dichlorovinyl)-L-cysteine sulfoxide, a potential reactive metabolite of trichloroethylene.

    Science.gov (United States)

    Irving, Roy M; Pinkerton, Marie E; Elfarra, Adnan A

    2013-02-15

    N-Acetyl-S-(1,2-dichlorovinyl)-L-cysteine (NA-DCVC) has been detected in the urine of humans exposed to trichloroethylene and its related sulfoxide, N-acetyl-S-(1,2-dichlorovinyl)-L-cysteine sulfoxide (NA-DCVCS), has been detected as hemoglobin adducts in blood of rats dosed with S-(1,2-dichlorovinyl)-L-cysteine (DCVC) or S-(1,2-dichlorovinyl)-L-cysteine sulfoxide (DCVCS). Because the in vivo nephrotoxicity of NA-DCVCS was unknown, in this study, male Sprague-Dawley rats were dosed (i.p.) with 230 μmol/kg b.w. NA-DCVCS or its potential precursors, DCVCS or NA-DCVC. At 24 h post treatment, rats given NA-DCVC or NA-DCVCS exhibited kidney lesions and effects on renal function distinct from those caused by DCVCS. NA-DCVC and NA-DCVCS primarily affected the cortico-medullary proximal tubules (S(2)-S(3) segments) while DCVCS primarily affected the outer cortical proximal tubules (S(1)-S(2) segments). When NA-DCVCS or DCVCS was incubated with GSH in phosphate buffer pH 7.4 at 37°C, the corresponding glutathione conjugates were detected, but NA-DCVC was not reactive with GSH. Because NA-DCVCS exhibited a longer half-life than DCVCS and addition of rat liver cytosol enhanced GSH conjugate formation, catalysis of GSH conjugate formation by the liver could explain the lower toxicity of NA-DCVCS in comparison with DCVCS. Collectively, these results provide clear evidence that NA-DCVCS formation could play a significant role in DCVC, NA-DCVC, and trichloroethylene nephrotoxicity. They also suggest a role for hepatic metabolism in the mechanism of NA-DCVC nephrotoxicity. Copyright © 2012 Elsevier Inc. All rights reserved.

  18. Chemical dependency and drug testing in the workplace.

    OpenAIRE

    Osterloh, J D; Becker, C E

    1990-01-01

    Urine testing for drug use in the workplace is now widespread, with the prevalence of positive drug tests in the work force being 0% to 15%. The prevalence of marijuana use is highest, and this can be reliably tested. Though it is prudent to rid the workplace of drug use, there is little scientific study on the relationship of drug use and workplace outcomes, such as productivity and safety. Probable-cause testing and preemployment testing are the most common applications. Random testing has ...

  19. A study on the chemical cleaning process and its qualification test by eddy current testing

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Ki Seok; Cheon, Keun Young; Nam, Min Woo [KHNP Central Research Institute, Daejeon (Korea, Republic of); Min, Kyoung Mahn [UMI Inc., Daejeon (Korea, Republic of)

    2013-12-15

    Steam Generator (SG) tube, as a barrier isolating the primary coolant system from the secondary side of nuclear power plants (NPP), must maintain the structural integrity for the public safety and their efficient power generation. So, SG tubes are subject to the periodic examination and the repairs if needed so that any defective tubes are not in service. Recently, corrosion related degradations were detected in the tubes of the domestic OPR-1000 NPP, as a form of axially oriented outer diameter stress corrosion cracking (ODSCC). According to the studies on the factors causing the heat fouling as well as developing corrosion cracking, densely scaled deposits on the secondary side of the SG tubes are mainly known to be problematic causing the adverse impacts against the soundness of the SG tubes. Therefore, the processes of various cleaning methods efficiently to dissolve and remove the deposits have been applied as well as it is imperative to maintain the structural integrity of the tubes after exposing to the cleaning agent. So qualification test (QT) should be carried out to assess the perfection of the chemical cleaning and QT is to apply the processes and to do ECT. In this paper, the chemical cleaning processes to dissolve and remove the scaled deposits are introduced and results of ECT on the artificial crack specimens to determine the effectiveness of those processes are represented.

  20. Characterization of the chemical reactivity and nephrotoxicity of N-acetyl-S-(1,2-dichlorovinyl)-L-cysteine sulfoxide, a potential reactive metabolite of trichloroethylene

    International Nuclear Information System (INIS)

    Irving, Roy M.; Pinkerton, Marie E.; Elfarra, Adnan A.

    2013-01-01

    N-Acetyl-S-(1,2-dichlorovinyl)-L-cysteine (NA-DCVC) has been detected in the urine of humans exposed to trichloroethylene and its related sulfoxide, N-acetyl-S-(1,2-dichlorovinyl)-L-cysteine sulfoxide (NA-DCVCS), has been detected as hemoglobin adducts in blood of rats dosed with S-(1,2-dichlorovinyl)-L-cysteine (DCVC) or S-(1,2-dichlorovinyl)-L-cysteine sulfoxide (DCVCS). Because the in vivo nephrotoxicity of NA-DCVCS was unknown, in this study, male Sprague–Dawley rats were dosed (i.p.) with 230 μmol/kg b.w. NA-DCVCS or its potential precursors, DCVCS or NA-DCVC. At 24 h post treatment, rats given NA-DCVC or NA-DCVCS exhibited kidney lesions and effects on renal function distinct from those caused by DCVCS. NA-DCVC and NA-DCVCS primarily affected the cortico-medullary proximal tubules (S 2 –S 3 segments) while DCVCS primarily affected the outer cortical proximal tubules (S 1 –S 2 segments). When NA-DCVCS or DCVCS was incubated with GSH in phosphate buffer pH 7.4 at 37 °C, the corresponding glutathione conjugates were detected, but NA-DCVC was not reactive with GSH. Because NA-DCVCS exhibited a longer half-life than DCVCS and addition of rat liver cytosol enhanced GSH conjugate formation, catalysis of GSH conjugate formation by the liver could explain the lower toxicity of NA-DCVCS in comparison with DCVCS. Collectively, these results provide clear evidence that NA-DCVCS formation could play a significant role in DCVC, NA-DCVC, and trichloroethylene nephrotoxicity. They also suggest a role for hepatic metabolism in the mechanism of NA-DCVC nephrotoxicity. - Highlights: ► NA-DCVCS and NA-DCVC toxicity are distinct from DCVCS toxicity. ► NA-DCVCS readily reacts with GSH to form mono- and di-GSH conjugates. ► Liver glutathione S-transferases enhance NA-DCVCS GSH conjugate formation. ► Renal localization of lesions suggests a role for NA-DCVCS in TCE nephrotoxicity

  1. Characterization of the chemical reactivity and nephrotoxicity of N-acetyl-S-(1,2-dichlorovinyl)-L-cysteine sulfoxide, a potential reactive metabolite of trichloroethylene

    Energy Technology Data Exchange (ETDEWEB)

    Irving, Roy M. [Molecular and Environmental Toxicology Center, University of Wisconsin-Madison, Madison, WI 53706 (United States); Pinkerton, Marie E. [Department of Pathobiological Sciences, University of Wisconsin-Madison, Madison, WI 53706 (United States); Elfarra, Adnan A., E-mail: elfarra@svm.vetmed.wisc.edu [Molecular and Environmental Toxicology Center, University of Wisconsin-Madison, Madison, WI 53706 (United States); Department of Comparative Biosciences, University of Wisconsin-Madison, Madison, WI 53706 (United States)

    2013-02-15

    N-Acetyl-S-(1,2-dichlorovinyl)-L-cysteine (NA-DCVC) has been detected in the urine of humans exposed to trichloroethylene and its related sulfoxide, N-acetyl-S-(1,2-dichlorovinyl)-L-cysteine sulfoxide (NA-DCVCS), has been detected as hemoglobin adducts in blood of rats dosed with S-(1,2-dichlorovinyl)-L-cysteine (DCVC) or S-(1,2-dichlorovinyl)-L-cysteine sulfoxide (DCVCS). Because the in vivo nephrotoxicity of NA-DCVCS was unknown, in this study, male Sprague–Dawley rats were dosed (i.p.) with 230 μmol/kg b.w. NA-DCVCS or its potential precursors, DCVCS or NA-DCVC. At 24 h post treatment, rats given NA-DCVC or NA-DCVCS exhibited kidney lesions and effects on renal function distinct from those caused by DCVCS. NA-DCVC and NA-DCVCS primarily affected the cortico-medullary proximal tubules (S{sub 2}–S{sub 3} segments) while DCVCS primarily affected the outer cortical proximal tubules (S{sub 1}–S{sub 2} segments). When NA-DCVCS or DCVCS was incubated with GSH in phosphate buffer pH 7.4 at 37 °C, the corresponding glutathione conjugates were detected, but NA-DCVC was not reactive with GSH. Because NA-DCVCS exhibited a longer half-life than DCVCS and addition of rat liver cytosol enhanced GSH conjugate formation, catalysis of GSH conjugate formation by the liver could explain the lower toxicity of NA-DCVCS in comparison with DCVCS. Collectively, these results provide clear evidence that NA-DCVCS formation could play a significant role in DCVC, NA-DCVC, and trichloroethylene nephrotoxicity. They also suggest a role for hepatic metabolism in the mechanism of NA-DCVC nephrotoxicity. - Highlights: ► NA-DCVCS and NA-DCVC toxicity are distinct from DCVCS toxicity. ► NA-DCVCS readily reacts with GSH to form mono- and di-GSH conjugates. ► Liver glutathione S-transferases enhance NA-DCVCS GSH conjugate formation. ► Renal localization of lesions suggests a role for NA-DCVCS in TCE nephrotoxicity.

  2. Critical experiment tests of bowing and expansion reactivity calculations for LMRS

    International Nuclear Information System (INIS)

    Schaefer, R.W.

    1988-01-01

    Experiments done in several LMR-type critical assemblies simulated core axial expansion, core radial expansion and bowing, coolant expansion, and control driveline expansion. For the most part new experimental techniques were developed to do these experiments. Calculations of the experiments basically used design-level methods, except when it was necessary to investigate complexities peculiar to the experiments. It was found that these feedback reactivities generally are overpredicted, but the predictions are within 30% of the experimental values. 14 refs., 2 figs., 4 tabs

  3. Analyzing relationships between surface perturbations and local chemical reactivity of metal sites: Alkali promotion of O2 dissociation on Ag(111)

    Science.gov (United States)

    Xin, Hongliang; Linic, Suljo

    2016-06-01

    Many commercial heterogeneous catalysts are complex structures that contain metal active sites promoted by multiple additives. Developing fundamental understanding about the impact of these perturbations on the local surface reactivity is crucial for catalyst development and optimization. In this contribution, we develop a general framework for identifying underlying mechanisms that control the changes in the surface reactivity of a metal site (more specifically the adsorbate-surface interactions) upon a perturbation in the local environment. This framework allows us to interpret fairly complex interactions on metal surfaces in terms of specific, physically transparent contributions that can be evaluated independently of each other. We use Cs-promoted dissociation of O2 as an example to illustrate our approach. We concluded that the Cs adsorbate affects the outcome of the chemical reaction through a strong alkali-induced electric field interacting with the static dipole moment of the O2/Ag(111) system.

  4. Chemical dispersibility testing of fresh and weathered oils

    International Nuclear Information System (INIS)

    Brandvik, P.J.; Daling, P.S.; Aareskjold, K.

    1991-05-01

    This activity in the DIspersants on Weathered Oils-project (DIWO) is a continuation and an extended study of the dispersibility study described in DIWO report No. 3. The main objective has been to study the chemical dispersibility of fresh and weathered oils produced or transported in Norwegian waters. Other important aims of this study have been: To correlate the effectiveness results obtained by three different laboratory methods; to determine the relationship between the dispersant effectiveness and the change in the oils' physico-chemical properties due to weathering (topping, photo-oxidation and w/o-emulsification). This study has been performed with 8 different oil types and 12 different weathering degrees of each oil type. The work performed clearly demonstrates that the oil type and especially the weathering properties are essential for the performance of dispersants at sea. 41 figs., 5 tabs., 16 refs

  5. Chemical dependency and drug testing in the workplace.

    Science.gov (United States)

    Osterloh, J D; Becker, C E

    1990-05-01

    Urine testing for drug use in the workplace is now widespread, with the prevalence of positive drug tests in the work force being 0% to 15%. The prevalence of marijuana use is highest, and this can be reliably tested. Though it is prudent to rid the workplace of drug use, there is little scientific study on the relationship of drug use and workplace outcomes, such as productivity and safety. Probable-cause testing and preemployment testing are the most common applications. Random testing has been less accepted owing to its higher costs, unresolved legal issues, and predictably poor test reliability. Legal issues have focused on the right to policy, discrimination, and the lack of due process. The legal cornerstone of a good program is a policy that is planned and agreed on by both labor and management, which serves both as a contract and as a procedure in which expectations and consequences are known. The National Institute on Drug Abuse is certifying laboratories doing employee drug testing. Testing methods when done correctly are less prone to error than in the past, but screening tests can be defeated by adulterants. Although the incidence of false-positive results is low, such tests are less reliable when the prevalence of drug abuse is also low.

  6. Cardiovascular reactivity to a marital conflict version of the Trier social stress test in intimate partner violence perpetrators.

    Science.gov (United States)

    Romero-Martínez, Angel; Nunes-Costa, Rui; Lila, Marisol; González-Bono, Esperanza; Moya-Albiol, Luis

    2014-07-01

    Intimate partner violence (IPV) perpetrators have been categorized into two groups based on their heart rate (HR) reactivity to stress following Gottman's studies. Overall, type I perpetrators tend to show autonomic underarousal, whereas type II or reactive perpetrators present a hyper-reactivity in anticipation of stress. In this study, changes in HR, pre-ejection period (PEP), vagal ratio as well as psychological state variables (anxiety and anger) in response to stress were assessed, comparing a group of type II IPV perpetrators (based on violence reports and psychological assessment; n = 17; mean age = 37) with non-violent controls (n = 17; mean age = 35) using modified version of the Trier Social Stress Test. IPV perpetrators had higher HRs and lower vagal ratios than controls, particularly during the recovery period. Moreover, the former presented shorter PEPs than controls. There were no differences between groups in the magnitude of response of the HR, PEP or vagal ratio. High baseline anxiety and anger were associated with an HR increase during the preparation time in IPV perpetrators but not in controls. These findings indicate a different cardiovascular pattern of response to psychosocial stress in IPV perpetrators, especially during recovery. Thus, they contribute to understanding the biological functioning of violence sub-types, supporting the validity of cardiovascular measures as diagnostic indicators for IPV classification.

  7. Assessment of soil phosphorus tests for situations in Australia where reactive phosphate rock and water-soluble fertilizers are used

    International Nuclear Information System (INIS)

    McLaughlin, M.J.

    2002-01-01

    A selection of commonly used soil P tests, which included anion and cation exchange resin membranes, were compared in a glasshouse experiment using subterranean clover, and evaluated in the field at 19 sites from the National Reactive Phosphate Rock Project in 1993 and at 6 sites in 1995. The ability of the soil P tests to predict plant response was used to evaluate the tests. In the glasshouse experiment, the resin test was less effective than the Bray and Colwell tests in its ability to assess the level of plant available P from the different fertilizer treatments. Seventy one percent of the variation in total P content of the subterranean clover tops was explained by resin extractable P values, whereas the Colwell procedure accounted for 81% and the Bray 1 procedure accounted for 78%. Water and CaCl 2 extracts were poor predictors of P content. In the field experiments, all tests evaluated performed poorly in describing the relationship between soil test P and the level of P applied and relative yield and soil test P over a wide range of soil types and environments. The best performing test was the Bray 1 test, though the relationship was poor. (author)

  8. Induction of molecular endpoints by reactive oxygen species in human lung cells predicted by physical chemical properties of engineered nanoparticles

    Science.gov (United States)

    A series of six titanium dioxide and two cerium oxide engineered nanomaterials were assessed for their ability to induce cytotoxicity, reactive oxygen species (ROS), and various types of DNA and protein damage in human respiratory BEAS-2B cells exposed in vitro for 72 hours at se...

  9. Physical and chemical test results of electrostatic safe flooring materials

    Science.gov (United States)

    Gompf, R. H.

    1988-01-01

    This test program was initiated because a need existed at the Kennedy Space Center (KSC) to have this information readily available to the engineer who must make the choice of which electrostatic safe floor to use in a specific application. The information, however, should be of value throughout both the government and private industry in the selection of a floor covering material. Included are the test results of 18 floor covering materials which by test evaluation at KSC are considered electrostatically safe. Tests were done and/or the data compiled in the following areas: electrostatics, flammability, hypergolic compatibility, outgassing, floor type, material thickness, and available colors. Each section contains the test method used to gather the data and the test results.

  10. An in vitro method for detecting chemical sensitization using human reconstructed skin models and its applicability to cosmetic, pharmaceutical, and medical device safety testing.

    Science.gov (United States)

    McKim, James M; Keller, Donald J; Gorski, Joel R

    2012-12-01

    Chemical sensitization is a serious condition caused by small reactive molecules and is characterized by a delayed type hypersensitivity known as allergic contact dermatitis (ACD). Contact with these molecules via dermal exposure represent a significant concern for chemical manufacturers. Recent legislation in the EU has created the need to develop non-animal alternative methods for many routine safety studies including sensitization. Although most of the alternative research has focused on pure chemicals that possess reasonable solubility properties, it is important for any successful in vitro method to have the ability to test compounds with low aqueous solubility. This is especially true for the medical device industry where device extracts must be prepared in both polar and non-polar vehicles in order to evaluate chemical sensitization. The aim of this research was to demonstrate the functionality and applicability of the human reconstituted skin models (MatTek Epiderm(®) and SkinEthic RHE) as a test system for the evaluation of chemical sensitization and its potential use for medical device testing. In addition, the development of the human 3D skin model should allow the in vitro sensitization assay to be used for finished product testing in the personal care, cosmetics, and pharmaceutical industries. This approach combines solubility, chemical reactivity, cytotoxicity, and activation of the Nrf2/ARE expression pathway to identify and categorize chemical sensitizers. Known chemical sensitizers representing extreme/strong-, moderate-, weak-, and non-sensitizing potency categories were first evaluated in the skin models at six exposure concentrations ranging from 0.1 to 2500 µM for 24 h. The expression of eight Nrf2/ARE, one AhR/XRE and two Nrf1/MRE controlled gene were measured by qRT-PCR. The fold-induction at each exposure concentration was combined with reactivity and cytotoxicity data to determine the sensitization potential. The results demonstrated that

  11. A randomized controlled trial to test the effect of multispecies probiotics on cognitive reactivity to sad mood.

    Science.gov (United States)

    Steenbergen, Laura; Sellaro, Roberta; van Hemert, Saskia; Bosch, Jos A; Colzato, Lorenza S

    2015-08-01

    Recent insights into the role of the human microbiota in cognitive and affective functioning have led to the hypothesis that probiotic supplementation may act as an adjuvant strategy to ameliorate or prevent depression. Heightened cognitive reactivity to normal, transient changes in sad mood is an established marker of vulnerability to depression and is considered an important target for interventions. The present study aimed to test if a multispecies probiotic containing Bifidobacterium bifidum W23, Bifidobacterium lactis W52, Lactobacillus acidophilus W37, Lactobacillus brevis W63, Lactobacillus casei W56, Lactobacillus salivarius W24, and Lactococcus lactis (W19 and W58) may reduce cognitive reactivity in non-depressed individuals. In a triple-blind, placebo-controlled, randomized, pre- and post-intervention assessment design, 20 healthy participants without current mood disorder received a 4-week probiotic food-supplement intervention with the multispecies probiotics, while 20 control participants received an inert placebo for the same period. In the pre- and post-intervention assessment, cognitive reactivity to sad mood was assessed using the revised Leiden index of depression sensitivity scale. Compared to participants who received the placebo intervention, participants who received the 4-week multispecies probiotics intervention showed a significantly reduced overall cognitive reactivity to sad mood, which was largely accounted for by reduced rumination and aggressive thoughts. These results provide the first evidence that the intake of probiotics may help reduce negative thoughts associated with sad mood. Probiotics supplementation warrants further research as a potential preventive strategy for depression. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

  12. Fixation of some chemically modified reactive dye during gamma irradiation of cotton fabrics in presence of vinyl and acrylic monomers

    International Nuclear Information System (INIS)

    Zohdy, M.H.; El-Naggar, A.M.; Abdallah, W.A.

    1999-01-01

    The radiation grafting of vinyl sulfone dye having an activated double bond in presence of styrene monomer or its mixtures with ethyl acrylate onto cotton fabric has been investigated. The chemical reaction of the vinyl sulfone form with peroxy radicals on cotton fabric through covalent bonding is tested by extracting the dyed samples in 50% aqueous DMF solution. It was found that the presence of styene monomer in the dyeing solution is essential for the reaction or grafting of the vinyl sulfone dye. However, when a constant styrene concentration of 5% was used in the dye bath, the color strength expressed as K/S was found to increase by increasing the dye concentration. The results showed that the color strength obtained in case of using 10% ethyl acrylate is much lower than in the case of using the same concentration of styrene monomer. A solvent composition of equal ratios of methanol and water has been proven to be suitable to produce the highest improvement in the color strength. The irradiation dose was found to play an important role in initiating the reaction of the vinyl sulfone dye

  13. Study of a new hybrid process combining slurry infiltration and Reactive Chemical Vapour Infiltration for the realisation of Ceramic Matrix Composites

    International Nuclear Information System (INIS)

    Ledain, Olivier

    2014-01-01

    Ceramic matrix composites were originally developed for aerospace,military aeronautics or energy applications thanks to their good properties at high temperature. They are generally made by Chemical Vapor Infiltration (CVI). A new short hybrid process combining fiber preform slurry impregnation of ceramic powders with an innovative Reactive CVI (RCVI) route is proposed to reduce the production time. This route is based on the combination of Reactive Chemical Vapour Deposition (RCVD), which is often used to deposit coatings on fibres, with the Chemical Vapor Infiltration (CVI).In RCVD, the absence of one element of the deposited carbide in the initial gas phase involves the consumption/conversion of the solid substrate. In this work, the RCVD growth and the associated consumption were studied with different parameters in the Ti-H-Cl-C chemical system. The study has been completed with the chemical products analysis, combining XRD, XPS and FTIR. Then, the partial conversion of sub-micrometer carbon powders into titanium carbide and the consolidation of green bodies by RCVI from H 2 /TiCl 4 gaseous infiltration were studied. The residual porosity and the final TiC content were measured in the bulk of the infiltrated powders by image analysis from scanning electron microscopy. Depending on temperature, few hundred micrometers-depth infiltrations are obtained.Finally, the results have been transposed to the RCVI into CMC-type pre-forms. Despite a minimal TiC content of 25% in the overall preform, the results shown a bad homogeneity of the infiltration and a poor cohesion of fibres with RCVI consolidated powder of their environment. (author) [fr

  14. Hot spot formation and chemical reaction initiation in shocked HMX crystals with nanovoids: a large-scale reactive molecular dynamics study.

    Science.gov (United States)

    Zhou, Tingting; Lou, Jianfeng; Zhang, Yangeng; Song, Huajie; Huang, Fenglei

    2016-07-14

    We report million-atom reactive molecular dynamic simulations of shock initiation of β-cyclotetramethylene tetranitramine (β-HMX) single crystals containing nanometer-scale spherical voids. Shock induced void collapse and subsequent hot spot formation as well as chemical reaction initiation are observed which depend on the void size and impact strength. For an impact velocity of 1 km s(-1) and a void radius of 4 nm, the void collapse process includes three stages; the dominant mechanism is the convergence of upstream molecules toward the centerline and the downstream surface of the void forming flowing molecules. Hot spot formation also undergoes three stages, and the principal mechanism is kinetic energy transforming to thermal energy due to the collision of flowing molecules on the downstream surface. The high temperature of the hot spot initiates a local chemical reaction, and the breakage of the N-NO2 bond plays the key role in the initial reaction mechanism. The impact strength and void size have noticeable effects on the shock dynamical process, resulting in a variation of the predominant mechanisms leading to void collapse and hot spot formation. Larger voids or stronger shocks result in more intense hot spots and, thus, more violent chemical reactions, promoting more reaction channels and generating more reaction products in a shorter duration. The reaction products are mainly concentrated in the developed hot spot, indicating that the chemical reactivity of the hmx crystal is greatly enhanced by void collapse. The detailed information derived from this study can aid a thorough understanding of the role of void collapse in hot spot formation and the chemical reaction initiation of explosives.

  15. Acute oral toxicity test of chemical compounds in silkworms.

    Science.gov (United States)

    Usui, Kimihito; Nishida, Satoshi; Sugita, Takuya; Ueki, Takuro; Matsumoto, Yasuhiko; Okumura, Hidenobu; Sekimizu, Kazuhisa

    2016-02-01

    This study performed an acute oral toxicity test of 59 compounds in silkworms. These compounds are listed in OECD guidelines as standard substances for a cytotoxicity test, and median lethal dose (LD(50)) werecalculated for each compound. Acute oral LD(50) values in mammals are listed in OECD guidelines and acute oral LD(50) values in silkworms were determined in this study. R(2) for the correlation between LD(50) values in mammals and LD(50) values in silkworms was 0.66. In addition, the acute oral toxicity test in silkworms was performed by two different facilities, and test results from the facilities were highly reproducible. These findings suggest that an acute oral toxicity test in silkworms is a useful way to evaluate the toxicity of compounds in mammals.

  16. Technical and economic feasibility study for the reactivation of the integral test facility of IPEN/CNEN Nuclear Engineering Center

    Energy Technology Data Exchange (ETDEWEB)

    Biaty, Flávia P.; Rocha, Marcelo da S.; Oliveira, Otávio L. de, E-mail: flavia.biaty@usp.br, E-mail: msrocha@ipen.br, E-mail: otavioluis@ipen.br [Instituto de Pesquisas Energéticas e Nucleares (IPEN/CNEN-SP), São Paulo, SP (Brazil)

    2017-07-01

    The Integral Test Facility of Nuclear Engineering Center (CEN/IPEN/CNEN-SP), known as 'Loop 70', is a semi-industrial thermal-hydraulic test facility and can operate as a BWR (Boiling Water Reactor) or a PWR (Pressurizing Water Reactor) mode. Designed and built in the 1980's, it is currently disabled. The experimental circuits ('test loop') are facilities that reproduce the thermohydraulic and fluid dynamic conditions that occur inside a reactor and are used to simulate the practical reality which it is not possible to be obtained through mathematical models. In this context, this research project aims the development of a Business Plan to analyze the technical and economic feasibility related to the reactivation of the facility. This methodology (adapted to the government sector) is a decision-making tool that will offer a wide perspective of the project, set the guidelines and actions that will define the future of the facility and provide a general rule to make investments on it. This paper presents the historic aspects to better understand the Loop 70's current situation. It also presents information about similar facilities around the world, services that can be offered (thermal-hydraulics parameters measurements, equipment qualification and transient analysis due accident situations), results of the strategic analysis (SWOT) performed, specific goals for each critical success or failure factor of the facility, financial aspects related to the reactivation and an overview of the facility's perspectives. (author)

  17. Increased preference for ethanol in the infant rat after prenatal ethanol exposure, expressed on intake and taste reactivity tests.

    Science.gov (United States)

    Arias, Carlos; Chotro, M Gabriela

    2005-03-01

    Previous studies have shown that prenatal exposure during gestational days 17 to 20 to low or moderate doses of ethanol (1 or 2 g/kg) increases alcohol intake in infant rats. Taking into account that higher consumption does not necessarily suggest a preference for alcohol, in the present study, the hedonic nature of the prenatal experience was analyzed further with the use of a taste reactivity test. General activity, wall climbing, passive drips, paw licking, and mouthing in response to intraoral infusions of alcohol, water, and a sucrose-quinine solution (which resembles alcohol taste in rats) were tested in 161 preweanling 14-day-old rat pups that were prenatally exposed to 0, 1, or 2 g/kg of alcohol during gestational days 17 to 20. Consumption of those substances was measured during the taste reactivity test and on postnatal day 15. Pups that were prenatally exposed to both doses of ethanol displayed lower levels of general activity and wall climbing than controls in response to ethanol. Infant rats that were treated prenatally with both doses of ethanol showed higher intake of the drug and also more mouthing and paw licking in response to ethanol taste. Only pups that were exposed to the higher ethanol dose in utero generalized those responses to the sucrose-quinine compound. These results seem to indicate that for the infant rat, the palatability of ethanol is enhanced after exposure to the drug during the last days of gestation.

  18. Technical and economic feasibility study for the reactivation of the integral test facility of IPEN/CNEN Nuclear Engineering Center

    International Nuclear Information System (INIS)

    Biaty, Flávia P.; Rocha, Marcelo da S.; Oliveira, Otávio L. de

    2017-01-01

    The Integral Test Facility of Nuclear Engineering Center (CEN/IPEN/CNEN-SP), known as 'Loop 70', is a semi-industrial thermal-hydraulic test facility and can operate as a BWR (Boiling Water Reactor) or a PWR (Pressurizing Water Reactor) mode. Designed and built in the 1980's, it is currently disabled. The experimental circuits ('test loop') are facilities that reproduce the thermohydraulic and fluid dynamic conditions that occur inside a reactor and are used to simulate the practical reality which it is not possible to be obtained through mathematical models. In this context, this research project aims the development of a Business Plan to analyze the technical and economic feasibility related to the reactivation of the facility. This methodology (adapted to the government sector) is a decision-making tool that will offer a wide perspective of the project, set the guidelines and actions that will define the future of the facility and provide a general rule to make investments on it. This paper presents the historic aspects to better understand the Loop 70's current situation. It also presents information about similar facilities around the world, services that can be offered (thermal-hydraulics parameters measurements, equipment qualification and transient analysis due accident situations), results of the strategic analysis (SWOT) performed, specific goals for each critical success or failure factor of the facility, financial aspects related to the reactivation and an overview of the facility's perspectives. (author)

  19. 76 FR 65385 - Testing of Certain High Production Volume Chemicals; Third Group of Chemicals

    Science.gov (United States)

    2011-10-21

    ... Mutations: Bacterial Reverse Mutation Test (in vitro): 40 CFR 799.9510. b. Chromosomal Damage: In Vitro... alternate test. 6. Mammalian Toxicity--Repeated Dose/Reproduction/Developmental--a. Combined Repeated Dose Toxicity Study with the Reproduction/ Developmental Toxicity Screening Test: 40 CFR 799.9365. b...

  20. C-reactive protein testing in patients with acute rhinosinusitis leads to a reduction in antibiotic use

    DEFF Research Database (Denmark)

    Llor, Carl; Bjerrum, Lars; Arranz, Javier

    2012-01-01

    OBJECTIVE: To evaluate the effect of C-reactive protein (CRP) testing on the antibiotic prescribing in patients with acute rhinosinusitis. METHODS: Audit-based study carried out in primary care centres in Spain. GPs registered episodes of rhinosinusitis during 3-week period before and after...... an intervention. Two types of intervention were considered: full intervention group (FIG) consisting in individual feedback based on results from the first registry, courses in rational antibiotic prescribing, guidelines, patient information leaflets, workshops on rapid tests and use of the CRP test. GPs...... in the partial intervention group (PIG) underwent all the above intervention except for the workshop and they did not have access to CRP. Multilevel logistic regression analysis was performed considering the prescription of antibiotics as the dependent variable. RESULTS: Two hundred and ten physicians were...

  1. 76 FR 77833 - Scientific Information Request on CYP2C19 Variants and Platelet Reactivity Tests

    Science.gov (United States)

    2011-12-14

    ... program. AHRQ is not requesting and will not consider marketing material, health economics information, or... of alternative test-and-treat strategies (including a no-testing strategy) for therapeutic decision...? a. What is the comparative effectiveness of the following testing strategies on therapeutic decision...

  2. Chemical analysis of reactive species and antimicrobial activity of/nwater treated by nanosecond pulsed DBD air plasma

    Czech Academy of Sciences Publication Activity Database

    Laurita, R.; Barbieri, D.; Gherardi, M.; Colombo, V.; Lukeš, Petr

    2015-01-01

    Roč. 3, č. 2 (2015), s. 53-61 ISSN 2212-8166 R&D Projects: GA MŠk(CZ) LD14080 Grant - others:European Cooperation in Science and Technology(XE) COST TD1208 Institutional support: RVO:61389021 Keywords : Dielectric barrier discharge * Plasma activated water * Reactive species * Peroxynitrite * Phenol degradation * Candida albicans * Staphylococcus aureus * Antimicrobial activity * Nosocomial infections Subject RIV: BL - Plasma and Gas Discharge Physics http://www.sciencedirect.com/science/article/pii/S2212816615300081

  3. Generation and Role of Reactive Oxygen and Nitrogen Species Induced by Plasma, Lasers, Chemical Agents, and Other Systems in Dentistry

    Science.gov (United States)

    Jha, Nayansi; Ryu, Jae Jun

    2017-01-01

    The generation of reactive oxygen and nitrogen species (RONS) has been found to occur during inflammatory procedures, during cell ischemia, and in various crucial developmental processes such as cell differentiation and along cell signaling pathways. The most common sources of intracellular RONS are the mitochondrial electron transport system, NADH oxidase, and cytochrome P450. In this review, we analyzed the extracellular and intracellular sources of reactive species, their cell signaling pathways, the mechanisms of action, and their positive and negative effects in the dental field. In dentistry, ROS can be found—in lasers, photosensitizers, bleaching agents, cold plasma, and even resin cements, all of which contribute to the generation and prevalence of ROS. Nonthermal plasma has been used as a source of ROS for biomedical applications and has the potential for use with dental stem cells as well. There are different types of dental stem cells, but their therapeutic use remains largely untapped, with the focus currently on only periodontal ligament stem cells. More research is necessary in this area, including studies about ROS mechanisms with dental cells, along with the utilization of reactive species in redox medicine. Such studies will help to provide successful treatment modalities for various diseases. PMID:29204250

  4. Increased retest reactivity by both patch and use test with methyldibromoglutaronitrile in sensitized individuals

    DEFF Research Database (Denmark)

    Jensen, Charlotte D; Johansen, Jeanne Duus; Menné, Torkil

    2006-01-01

    -exposure by both a patch test challenge and a use test with a liquid soap preserved with MDBGN. MDBGN dermatitis was elicited on the back and arms of sensitized individuals. One month later the previously eczematous areas were challenged with MDBGN. On the back, the test sites were patch-tested with a serial...... dilution of MDBGN and a use test was performed on the arms with an MDBGN-containing soap. A statistically significant increased response was seen on the areas with previous dermatitis on the back. Eight of the nine patients who developed dermatitis on the arms from the MDBGN-containing soap had...

  5. Leach testing of Idaho Chemical Processing Plant final waste forms

    International Nuclear Information System (INIS)

    Schuman, R.P.

    1980-01-01

    A number of pellets and highly durable glasses prepared from nonradioactive-simulated high-level wasste calcines have been leach tested. The leach tests are patterned on the IAEA standard test and the proposed Materials Characterization Center tests. Most tests are made with static distilled water at 25, 70, 95, 250, and 350 0 C and in refluxing distilled water, Soxhlet, at 95 0 C. Leach rates are determined by analyzing the leachate by instrumental activation analysis or spectrochemical analysis and from weight loss. Leaches are run on glass using cast and core drilled cylinders, broken pieces and coarse ground material. Sample form has a considerable effect on leach rates; solid pieces gave higher leach rates than ground glass when expressed in g/cm 2 /day. Cesium, molybdenum and weight loss leach rates of cast glass cylinders in distilled water varied from -7 g/cm 7 /day at 25 0 C to approx. 10 -3 g/cm 2 /day at 250 0 C. The leach rates in static distilled water at 95 0 C were considerably lower than those in refluxing distilled water, Soxhlet, at the same temperature. Even at 25 0 C, sodium, cesium, and molybdenum readily leached from the porous pellets, but the pellets showed no visible attack, even at 250 0 C

  6. Host-cell reactivation of UV-irradiated and chemically-treated herpes simplex virus-1 by xeroderma pigmentosum, xp heterozygotes and normal skin fibroblasts

    International Nuclear Information System (INIS)

    Selsky, C.A.

    1978-01-01

    The host-cell reactivation of UV-irradiated and N-acetoxy-2-acetylamino-fluorene-treated herpes simplex virus type 1 strain MP was studied in normal and xeroderma pigmentosum human skin fibroblasts. Virus treated with either agent demonstrated lower survival in XP cells from complementation groups A, B, C and D than in normal fibroblasts. The relative reactivation ability of XP cells from the different genetic complementation groups was found to be the same for both irradiated and chemically treated virus. In addition, the inactivation kinetics for virus treated with either agent in the XP variant were comparable to that seen in normal skin fibroblasts. The addition of 2 or 4 mmoles caffeine to the post-infection assay medium had no effect on the inactivation kinetics of virus treated by either agent in the XP variant or in XP cells from the different genetic complementation groups. Treatment of the virus with nitrogen mustard resulted in equivalent survival in normal and XP genetic complementation group D cells. No apparent defect was observed in the ability of XP heterozygous skin fibroblasts to repair virus damaged with up to 100 μg N-acetoxy-2-acetylaminofluorene per ml. These findings indicate that the repair of UV-irradiated and N-acetoxy-2-acetylaminofluorene-treated virus is accomplished by the same pathway or different pathways sharing a common intermediate step and that the excision defect of XP cells plays little if any role in the reactivation of nitrogen mustard treated virus. (Auth.)

  7. Oral Administration of the Japanese Traditional Medicine Keishibukuryogan-ka-yokuinin Decreases Reactive Oxygen Metabolites in Rat Plasma: Identification of Chemical Constituents Contributing to Antioxidant Activity

    Directory of Open Access Journals (Sweden)

    Yosuke Matsubara

    2017-02-01

    Full Text Available Insufficient detoxification and/or overproduction of reactive oxygen species (ROS induce cellular and tissue damage, and generated reactive oxygen metabolites become exacerbating factors of dermatitis. Keishibukuryogan-ka-yokuinin (KBGY is a traditional Japanese medicine prescribed to treat dermatitis such as acne vulgaris. Our aim was to verify the antioxidant properties of KBGY, and identify its active constituents by blood pharmacokinetic techniques. Chemical constituents were quantified in extracts of KBGY, crude components, and the plasma of rats treated with a single oral administration of KBGY. Twenty-three KBGY compounds were detected in plasma, including gallic acid, prunasin, paeoniflorin, and azelaic acid, which have been reported to be effective for inflammation. KBGY decreased level of the diacron-reactive oxygen metabolites (d-ROMs in plasma. ROS-scavenging and lipid hydroperoxide (LPO generation assays revealed that gallic acid, 3-O-methylgallic acid, (+-catechin, and lariciresinol possess strong antioxidant activities. Gallic acid was active at a similar concentration to the maximum plasma concentration, therefore, our findings indicate that gallic acid is an important active constituent contributing to the antioxidant effects of KBGY. KBGY and its active constituents may improve redox imbalances induced by oxidative stress as an optional treatment for skin diseases.

  8. In vitro screening of environmental chemicals for targeted testing prioritization: the ToxCast project.

    Science.gov (United States)

    Judson, Richard S; Houck, Keith A; Kavlock, Robert J; Knudsen, Thomas B; Martin, Matthew T; Mortensen, Holly M; Reif, David M; Rotroff, Daniel M; Shah, Imran; Richard, Ann M; Dix, David J

    2010-04-01

    Chemical toxicity testing is being transformed by advances in biology and computer modeling, concerns over animal use, and the thousands of environmental chemicals lacking toxicity data. The U.S. Environmental Protection Agency's ToxCast program aims to address these concerns by screening and prioritizing chemicals for potential human toxicity using in vitro assays and in silico approaches. This project aims to evaluate the use of in vitro assays for understanding the types of molecular and pathway perturbations caused by environmental chemicals and to build initial prioritization models of in vivo toxicity. We tested 309 mostly pesticide active chemicals in 467 assays across nine technologies, including high-throughput cell-free assays and cell-based assays, in multiple human primary cells and cell lines plus rat primary hepatocytes. Both individual and composite scores for effects on genes and pathways were analyzed. Chemicals displayed a broad spectrum of activity at the molecular and pathway levels. We saw many expected interactions, including endocrine and xenobiotic metabolism enzyme activity. Chemicals ranged in promiscuity across pathways, from no activity to affecting dozens of pathways. We found a statistically significant inverse association between the number of pathways perturbed by a chemical at low in vitro concentrations and the lowest in vivo dose at which a chemical causes toxicity. We also found associations between a small set of in vitro assays and rodent liver lesion formation. This approach promises to provide meaningful data on the thousands of untested environmental chemicals and to guide targeted testing of environmental contaminants.

  9. Development of an artificial neural network model for risk assessment of skin sensitization using human cell line activation test, direct peptide reactivity assay, KeratinoSens™ and in silico structure alert parameter.

    Science.gov (United States)

    Hirota, Morihiko; Ashikaga, Takao; Kouzuki, Hirokazu

    2018-04-01

    It is important to predict the potential of cosmetic ingredients to cause skin sensitization, and in accordance with the European Union cosmetic directive for the replacement of animal tests, several in vitro tests based on the adverse outcome pathway have been developed for hazard identification, such as the direct peptide reactivity assay, KeratinoSens™ and the human cell line activation test. Here, we describe the development of an artificial neural network (ANN) prediction model for skin sensitization risk assessment based on the integrated testing strategy concept, using direct peptide reactivity assay, KeratinoSens™, human cell line activation test and an in silico or structure alert parameter. We first investigated the relationship between published murine local lymph node assay EC3 values, which represent skin sensitization potency, and in vitro test results using a panel of about 134 chemicals for which all the required data were available. Predictions based on ANN analysis using combinations of parameters from all three in vitro tests showed a good correlation with local lymph node assay EC3 values. However, when the ANN model was applied to a testing set of 28 chemicals that had not been included in the training set, predicted EC3s were overestimated for some chemicals. Incorporation of an additional in silico or structure alert descriptor (obtained with TIMES-M or Toxtree software) in the ANN model improved the results. Our findings suggest that the ANN model based on the integrated testing strategy concept could be useful for evaluating the skin sensitization potential. Copyright © 2017 John Wiley & Sons, Ltd.

  10. Experimental data report for test TS-3 Reactivity Initiated Accident test in the NSRR with pre-irradiated BWR fuel rod

    International Nuclear Information System (INIS)

    Nakamura, Takehiko; Yoshinaga, Makio; Fujishiro, Toshio; Kobayashi, Shinsho; Yamahara, Takeshi; Sukegawa, Tomohide; Kikuchi, Teruo; Sobajima, Makoto.

    1993-09-01

    This report presents experimental data for Test TS-3 which was the third test in a series of Reactivity Initiated Accident (RIA) tests using pre-irradiated BWR fuel rods, performed in the Nuclear Safety Research Reactor (NSRR) in September, 1990. Test fuel rod used in the Test TS-3 was a short-sized BWR (7 x 7) type rod which was re-fabricated from a commercial rod irradiated in the Tsuruga Unit 1 power reactor of Japan Atomic Power Co. The fuel had an initial enrichment of 2.79 % and a burnup of 26 Gwd/tU. A pulse irradiation of the test fuel rod was performed under a cooling condition of stagnant water at atmospheric pressure and at ambient temperature which simulated a BWR's cold start-up RIA event. The energy deposition of the fuel rod in this test was evaluated to be 94 ± 4 cal/g · fuel (88 ± 4 cal/g · fuel in peak fuel enthalpy) and no fuel failure was observed. Descriptions on test conditions, test procedures, transient behavior of the test rod during the pulse irradiation, and results of pre-pulse and post-pulse irradiation examinations are described in this report. (author)

  11. Guidance on the Stand Down, Mothball, and Reactivation of Ground Test Facilities

    Science.gov (United States)

    Volkman, Gregrey T.; Dunn, Steven C.

    2013-01-01

    The development of aerospace and aeronautics products typically requires three distinct types of testing resources across research, development, test, and evaluation: experimental ground testing, computational "testing" and development, and flight testing. Over the last twenty plus years, computational methods have replaced some physical experiments and this trend is continuing. The result is decreased utilization of ground test capabilities and, along with market forces, industry consolidation, and other factors, has resulted in the stand down and oftentimes closure of many ground test facilities. Ground test capabilities are (and very likely will continue to be for many years) required to verify computational results and to provide information for regimes where computational methods remain immature. Ground test capabilities are very costly to build and to maintain, so once constructed and operational it may be desirable to retain access to those capabilities even if not currently needed. One means of doing this while reducing ongoing sustainment costs is to stand down the facility into a "mothball" status - keeping it alive to bring it back when needed. Both NASA and the US Department of Defense have policies to accomplish the mothball of a facility, but with little detail. This paper offers a generic process to follow that can be tailored based on the needs of the owner and the applicable facility.

  12. Aggressive chemical decontamination tests on small valves from the Garigliano BWR

    International Nuclear Information System (INIS)

    Bregani, F.

    1990-01-01

    In order to check the effectiveness of direct chemical decontamination on small and complex components, usually considered for storage without decontamination because of the small amount, some tests were performed on the DECO experimental loop. Four small stainless steel valves from the primary system of the Garigliano BWR were decontaminated using mainly aggressive chemicals such as HC1, HF, HNO 3 and their mixtures. On two valves, before the treatment with aggressive chemicals, a step with soft chemical (oxalic and citric acid mixture) was performed in order to see whether a softening action enhances the following aggressive decontamination. Moreover, in order to increase as much as possible the decontamination effectiveness, a decontamination process using ultrasounds jointly with aggressive chemicals was investigated. After an intensive laboratory testing programme, two smaller stainless steel valves from the primary system of the Garigliano BWR were decontaminated using ultrasounds in aggressive chemical solutions

  13. 78 FR 69414 - Toxic Substances Control Act Chemical Testing; Receipt of Test Data

    Science.gov (United States)

    2013-11-19

    ...; Acute emulsion polymerization in Inhalation Toxicity in paper, textile, fiber, and Rats; Bacterial.../ Reproduction Development Toxicity. Note: CAS No. = Chemical Abstracts Service Registry Number. Authority: 15 U...

  14. In Vitro Screening of Environmental Chemicals for Targeted Testing Prioritization: The ToxCast Project

    OpenAIRE

    Judson, Richard S.; Houck, Keith A.; Kavlock, Robert J.; Knudsen, Thomas B.; Martin, Matthew T.; Mortensen, Holly M.; Reif, David M.; Rotroff, Daniel M.; Shah, Imran; Richard, Ann M.; Dix, David J.

    2009-01-01

    Background Chemical toxicity testing is being transformed by advances in biology and computer modeling, concerns over animal use, and the thousands of environmental chemicals lacking toxicity data. The U.S. Environmental Protection Agency?s ToxCast program aims to address these concerns by screening and prioritizing chemicals for potential human toxicity using in vitro assays and in silico approaches. Objectives This project aims to evaluate the use of in vitro assays for understanding the ty...

  15. Chemical test for mammalian feces in grain products: collaborative study.

    Science.gov (United States)

    Gerber, H R

    1989-01-01

    A collaborative study was conducted to validate the use of the AOAC alkaline phosphatase method for mammalian feces in corn meal, 44.B01-44.B06, for 7 additional products: brown rice cream, oat bran, grits, semolina, pasta flour, farina, and barley plus (a mixture of barley, oat bran, and brown rice). The proposed method determines the presence of alkaline phosphatase, an enzyme contained in mammalian feces, by using phenolphthalein diphosphate as the enzyme substrate in a test agar medium. Fecal matter is separated from the grain products by specific gravity differences in 1% test agar. As the product is distributed on liquid test agar, fecal fragments float while the grain products sink. The alkaline phosphatase cleaves phosphate radicals from phenolphthalein diphosphate, generating free phenolphthalein, which produces a pink to red-purple color around the fecal particles in the previously colorless medium. Collaborators' recovery averages ranged from 21.7 particles (72.3%) for oat bran to 25.3 particles (84.3%) for semolina at the 30 particle spike level. Overall average background was 0.4 positive reactions per food type. The collaborators reported that the method was quick, simple, and easy to use. The method has been approved interim official first action for all 7 grain products.

  16. Standard test method for electrochemical reactivation (EPR) for detecting sensitization of AISI type 304 and 304L stainless steels

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    1994-01-01

    1.1 This test method covers a laboratory procedure for conducting an electrochemical reactivation (EPR) test on AISI Type 304 and 304L (UNS No. S30400 and S30403, respectively) stainless steels. This test method can provide a nondestructive means of quantifying the degree of sensitization in these steels (1, 2, 3). This test method has found wide acceptance in studies of the effects of sensitization on intergranular corrosion and intergranular stress corrosion cracking behavior (see Terminology G15). The EPR technique has been successfully used to evaluate other stainless steels and nickel base alloys (4), but the test conditions and evaluation criteria used were modified in each case from those cited in this test method. 1.2 The values stated in SI units are to be regarded as the standard. The inch-pound units given in parentheses are for information only. 1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this...

  17. Chemical and mineralogical characterization of highly and less reactive coal from Northern Natal and Venda-Pafuri coalfields in South Africa

    Science.gov (United States)

    Kataka, M. O.; Matiane, A. R.; Odhiambo, B. D. O.

    2018-01-01

    Spontaneous combustion of coal is a major hazard associated with the coal mining industry over centuries. It also a major cause of underground fires in South African collieries and in opencast operations, spoil heaps and stockpiles. Spontaneous combustion incidents are manifested in all major aspects of coal mining namely, underground mining, surface mining, including during sea-borne transportation, storage and waste disposal. Previous studies indicate that there are various factors (both intrinsic and extrinsic) that influence the spontaneous combustion of coals. This paper characterizes highly reactive coal from the Vryheid coalfields and less reactive coal from at Venda-Pafuri coalfield, to identify and delineate some intrinsic coal parameters that are considered to be most critical in terms of heat 'generation' and relationships between the two coals types by tracing their similarities and differences in their spontaneous combustion parameters. Various tests were carried out to characterize these coals in terms of their intrinsic properties, namely: ultimate, proximate, petrographic analysis and Glasser spontaneous tests. The ultimate and proximate analysis showed that spontaneous coal has high contents of carbon, oxygen, and volatile matter as compared to non-spontaneous coal, making it more susceptible to spontaneous combustion. Non-spontaneous coal has higher ash content than the spontaneous coal. Furthermore, the petrographic analysis showed that spontaneous coal has high total reactivity compared to the non-spontaneous coal. Results from Glasser spontaneous test indicate that spontaneous coal absorbs more oxygen than non-spontaneous coal, which explains why spontaneous coal is more susceptible to spontaneous combustion. High reactive coal has low values of critical self-heating temperature (CSHT), indicating that this coal has potential of spontaneous ignition.

  18. Physico-chemical properties of manufactured nanomaterials - Characterisation and relevant methods. An outlook based on the OECD Testing Programme.

    NARCIS (Netherlands)

    Rasmussen, Kirsten; Rauscher, Hubert; Mech, Agnieszka; Riego Sintes, Juan; Gilliland, Douglas; González, Mar; Kearns, Peter; Moss, Kenneth; Visser, Maaike; Groenewold, Monique; Bleeker, Eric A J

    Identifying and characterising nanomaterials require additional information on physico-chemical properties and test methods, compared to chemicals in general. Furthermore, regulatory decisions for chemicals are usually based upon certain toxicological properties, and these effects may not be

  19. Toxic Industrial Chemical Tests of Resistance to Permeation by Protective Suits

    National Research Council Canada - National Science Library

    Klemperer, Elizabeth

    2005-01-01

    A Natick program to select and test protective materials for soldiers and first responders who face a threat from chemical accidents or terrorist attacks was applied under Congressional legislation...

  20. Project W-314 Polyurea Special Protective Coating (SPC) Test Plan Chemical Compatibility and Physical Characteristics Testing

    International Nuclear Information System (INIS)

    MAUSER, R.W.

    2001-01-01

    This Test Plan outlines the testing to be done on the Special Protective Coating (SPC) Polyurea which includes: Tank Waste Compatibility, Decontamination Factor Testing, and Adhesion Strength Testing after a sample has been exposed to Radiation

  1. Quantitative sensory testing and pain-evoked cytokine reactivity: comparison of patients with sickle cell disease to healthy matched controls.

    Science.gov (United States)

    Campbell, Claudia M; Carroll, C Patrick; Kiley, Kasey; Han, Dingfen; Haywood, Carlton; Lanzkron, Sophie; Swedberg, Lauren; Edwards, Robert R; Page, Gayle G; Haythornthwaite, Jennifer A

    2016-04-01

    Sickle cell disease (SCD) is an inherited blood disorder associated with significant morbidity, which includes severe episodic pain, and, often, chronic pain. Compared to healthy individuals, patients with SCD report enhanced sensitivity to thermal detection and pain thresholds and have altered inflammatory profiles, yet no studies to date have examined biomarker reactivity after laboratory-induced pain. We sought to examine this relationship in patients with SCD compared to healthy control participants. We completed quantitative sensory testing in 83 patients with SCD and sequential blood sampling in 27 of them, whom we matched (sex, age, race, body mass index, and education) to 27 healthy controls. Surprisingly, few quantitative sensory testing differences emerged between groups. Heat pain tolerance, pressure pain threshold at the trapezius, thumb, and quadriceps, and thermal temporal summation at 45°C differed between groups in the expected direction, whereas conditioned pain modulation and pain ratings to hot water hand immersion were counterintuitive, possibly because of tailoring the water temperature to a perceptual level; patients with SCD received milder temperatures. In the matched subsample, group differences and group-by-time interactions were observed in biomarkers including tumor necrosis factor alpha, interleukin-1ß, interleukin-4, and neuropeptide Y. These findings highlight the utility of laboratory pain testing methods for understanding individual differences in inflammatory cytokines. Our findings suggest amplified pain-evoked proinflammatory cytokine reactivity among patients with SCD relative to carefully matched controls. Future research is warranted to evaluate the impact of enhanced pain-related cytokine response and whether it is predictive of clinical characteristics and the frequency/severity of pain crises in patients with SCD.

  2. Using laboratory flow experiments and reactive chemical transport modeling for designing waterflooding of the Agua Fria Reservoir, Poza Rica-Altamira Field, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Birkle, P.; Pruess, K.; Xu, T.; Figueroa, R.A. Hernandez; Lopez, M. Diaz; Lopez, E. Contreras

    2008-10-01

    Waterflooding for enhanced oil recovery requires that injected waters must be chemically compatible with connate reservoir waters, in order to avoid mineral dissolution-and-precipitation cycles that could seriously degrade formation permeability and injectivity. Formation plugging is a concern especially in reservoirs with a large content of carbonates, such as calcite and dolomite, as such minerals typically react rapidly with an aqueous phase, and have strongly temperature-dependent solubility. Clay swelling can also pose problems. During a preliminary waterflooding pilot project, the Poza Rica-Altamira oil field, bordering the Gulf coast in the eastern part of Mexico, experienced injectivity loss after five months of reinjection of formation waters into well AF-847 in 1999. Acidizing with HCl restored injectivity. We report on laboratory experiments and reactive chemistry modeling studies that were undertaken in preparation for long-term waterflooding at Agua Frma. Using analogous core plugs obtained from the same reservoir interval, laboratory coreflood experiments were conducted to examine sensitivity of mineral dissolution and precipitation effects to water composition. Native reservoir water, chemically altered waters, and distilled water were used, and temporal changes in core permeability, mineral abundances and aqueous concentrations of solutes were monitored. The experiments were simulated with the multi-phase, nonisothermal reactive transport code TOUGHREACT, and reasonable to good agreement was obtained for changes in solute concentrations. Clay swelling caused an additional impact on permeability behavior during coreflood experiments, whereas the modeled permeability depends exclusively on chemical processes. TOUGHREACT was then used for reservoir-scale simulation of injecting ambient-temperature water (30 C, 86 F) into a reservoir with initial temperature of 80 C (176 F). Untreated native reservoir water was found to cause serious porosity and

  3. Medium scale test study of chemical cleaning technique for secondary side of SG in PWR

    International Nuclear Information System (INIS)

    Zhang Mengqin; Zhang Shufeng; Yu Jinghua; Hou Shufeng

    1997-08-01

    The medium scale test study of chemical cleaning technique for removing corrosion product (Fe 3 O 4 ) in secondary side of SG in PWR has been completed. The test has been carried out in a medium scale test loop. The medium scale test evaluated the effect of the chemical cleaning technique (temperature, flow rate, cleaning time, cleaning process), the state of corrosion product deposition on magnetite (Fe 3 O 4 ) solubility and safety of materials of SG in cleaning process. The inhibitor component of chemical cleaning agent has been improved by electrochemical linear polarization method, the effect of inhibitor on corrosion resistance of materials have been examined in the medium scale test loop, the most components of chemical cleaning agent have been obtained, the EDTA is main component in cleaning agent. The electrochemical method for monitor corrosion of materials during cleaning process has been completed in the laboratory. The study of the medium scale test of chemical cleaning technique have had the optimum chemical cleaning technique for remove corrosion product in SG secondary side of PWR. (9 refs., 4 figs., 11 tabs.)

  4. Engineering of the chemical reactivity of the Ti/HfO₂ interface for RRAM: experiment and theory.

    Science.gov (United States)

    Calka, Pauline; Sowinska, Malgorzata; Bertaud, Thomas; Walczyk, Damian; Dabrowski, Jarek; Zaumseil, Peter; Walczyk, Christian; Gloskovskii, Andrei; Cartoixà, Xavier; Suñé, Jordi; Schroeder, Thomas

    2014-04-09

    The Ti/HfO2 interface plays a major role for resistance switching performances. However, clear interface engineering strategies to achieve reliable and reproducible switching have been poorly investigated. For this purpose, we present a comprehensive study of the Ti/HfO2 interface by a combined experimental-theoretical approach. Based on the use of oxygen-isotope marked Hf*O2, the oxygen scavenging capability of the Ti layer is clearly proven. More importantly, in line with ab initio theory, the combined HAXPES-Tof-SIMS study of the thin films deposited by MBE clearly establishes a strong impact of the HfO2 thin film morphology on the Ti/HfO2 interface reactivity. Low-temperature deposition is thus seen as a RRAM processing compatible way to establish the critical amount of oxygen vacancies to achieve reproducible and reliable resistance switching performances.

  5. Probing the reactivity of nucleophile residues in human 2,3-diphosphoglycerate/deoxy-hemoglobin complex by aspecific chemical modifications.

    Science.gov (United States)

    Scaloni, A; Ferranti, P; De Simone, G; Mamone, G; Sannolo, N; Malorni, A

    1999-06-11

    The use of aspecific methylation reaction in combination with MS procedures has been employed for the characterization of the nucleophilic residues present on the molecular surface of the human 2,3-diphosphoglycerate/deoxy-hemoglobin complex. In particular, direct molecular weight determinations by ESMS allowed to control the reaction conditions, limiting the number of methyl groups introduced in the modified globin chains. A combined LCESMS-Edman degradation approach for the analysis of the tryptic peptide mixtures yielded to the exact identification of methylation sites together with the quantitative estimation of their degree of modification. The reactivities observed were directly correlated with the pKa and the relative surface accessibility of the nucleophilic residues, calculated from the X-ray crystallographic structure of the protein. The results here described indicate that this methodology can be efficiently used in aspecific modification experiments directed to the molecular characterization of the surface topology in proteins and protein complexes.

  6. Evaluation by the Double Loop Electrochemical Potentiokinetic Reactivation Test of Aged Ferritic Stainless Steel Intergranular Corrosion Susceptibility

    Science.gov (United States)

    Sidhom, H.; Amadou, T.; Braham, C.

    2010-12-01

    An experimental design method was used to determine the effect of factors that significantly affect the response of the double loop-electrochemical potentiokinetic reactivation (DL-EPR) test in controlling the susceptibility to intergranular corrosion (IGC) of UNS S43000 (AISI 430) ferritic stainless steel. The test response is expressed in terms of the reactivation/activation current ratio ( I r / I a pct). Test results analysed by the analysis of variance (ANOVA) method show that the molarity of the H2SO4 electrolyte and the potential scanning rate have a more significant effect on the DL-EPR test response than the temperature and the depassivator agent concentration. On the basis of these results, a study was conducted in order to determine the optimal operating conditions of the test as a nondestructive technique for evaluating IGC resistance of ferritic stainless steel components. Three different heat treatments are considered in this study: solution annealing (nonsensitized), aging during 3 hours at 773 K (500 °C) (slightly sensitized), and aging during 2 hours at 873 K (600 °C) (highly sensitized). The aim is to find the operating conditions that simultaneously ensure the selectivity of the attack (intergranular and chromium depleted zone) and are able to detect the effect of low dechromization. It is found that a potential scanning rate of 2.5 mV/s in an electrolyte composed of H2SO4 3 M solution without depassivator, at a temperature around 293 K (20 °C), is the optimal operating condition for the DL-EPR test. Using this condition, it is possible to assess the degree of sensitization (DOS) to the IGC of products manufactured in ferritic stainless steels rapidly, reliably, and quantitatively. A time-temperature-start of sensitization (TTS) diagram for the UNS S43000 (France Inox, Villepinte, France) stainless steel was obtained with acceptable accuracy by this method when the IGC sensitization criterion was set to I r / I a > 1 pct. This diagram is in

  7. Investigating the Chemical Reactivity for Hydrogen in Siliciclastic Sediments: two Work Packages of the H2STORE Project

    Science.gov (United States)

    De Lucia, M.; Pilz, P.

    2014-12-01

    The H2STORE ("Hydrogen to Store") collaborative project, funded by the German government, investigates the feasibility of industrial-scale hydrogen storage from excess wind energy in siliciclastic depleted gas and oil reservoirs or suitable saline aquifers. In particular, two work packages (geochemical experiments and modelling) hosted at the German Research Centre for Geosciences (GFZ) focus on the possible impact of hydrogen on formation fluids and on the mineralogical, geochemical and petrophysical properties of reservoirs and caprocks. Laboratory experiments expose core samples from several potential reservoirs to pure hydrogen or hydrogen mixtures under site-specific conditions (temperatures up to 200 °C and pressure up to 300 bar). The resulting qualitative and, whereas possible, quantitative data are expected to ameliorate the precision of predictive geochemical and reactive transport modelling, which is also performed within the project. The combination of experiments and models will improve the knowledge about: (1) solubility model and mixing rule for of hydrogen and its gas mixtures in high saline formation fluids; (2) hydrogen reactivity in a broad spectrum of P-T conditions; (3) thermodynamics and kinetics of mineral dissolution or precipitation reactions and redox processes. It is known that under specific P-T conditions reactions between hydrogen and anorganic rock components such as carbonates can occur. However these conditions have never been precisely defined to date. A precise estimation of the hydrogen impact on reservoir behavior of different siliciclastic rock types is crucial for site selection and optimization of storage depth. Enhancing the overall understanding of such systems will benefit the operational reliability, the ecological tolerance, and the economic efficiency of future energy storing plants, crucial aspects for public acceptance and for industrial investors.

  8. Cost-effectiveness of point-of-care C-reactive protein testing to inform antibiotic prescribing decisions

    Science.gov (United States)

    Oppong, Raymond; Jit, Mark; Smith, Richard D; Butler, Christopher C; Melbye, Hasse; Mölstad, Sigvard; Coast, Joanna

    2013-01-01

    Background Point-of-care C-reactive protein (POCCRP) is a biomarker of inflammation that offers clinicians a rapid POC test to guide antibiotic prescribing decisions for acute cough and lower respiratory tract infections (LRTI). However, evidence that POCCRP is cost-effective is limited, particularly outside experimental settings. Aim To assess the cost-effectiveness of POCCRP as a diagnostic tool for acute cough and LRTI from the perspective of the health service. Design and setting Observational study of the presentation, management, and outcomes of patients with acute cough and LRTI in primary care settings in Norway and Sweden. Method Using hierarchical regression, data were analysed in terms of the effect on antibiotic use, cost, and patient outcomes (symptom severity after 7 and 14 days, time to recovery, and EQ-5D), while controlling for patient characteristics (self-reported symptom severity, comorbidities, and health-related quality of life) at first attendance. Results POCCRP testing is associated with non-significant positive reductions in antibiotic prescribing (P = 0.078) and increased cost (P = 0.092). Despite the uncertainty, POCCRP testing is also associated with a cost per quality-adjusted life year (QALY) gain of €9391. At a willingness-to-pay threshold of €30 000 per QALY gained, there is a 70% probability of CRP being cost-effective. Conclusion POCCRP testing is likely to provide a cost-effective diagnostic intervention both in terms of reducing antibiotic prescribing and in terms of QALYs gained. PMID:23834883

  9. Lessons Learned from the Construction of Upgrades to the NASA Glenn Icing Research Tunnel and Re-activation Testing

    Science.gov (United States)

    Sheldon, David W.; Andracchio, Charles R.; Krivanek, Thomas M.; Spera, David A.; Austinson, Todd A.

    2001-01-01

    Major upgrades were made in 1999 to the 6- by 9-Foot (1.8- by 2.7-m) Icing Research Tunnel (IRT) at the NASA Glenn Research Center. These included replacement of the electronic controls for the variable-speed drive motor, replacement of the heat exchanger, complete replacement and enlargement of the leg of the tunnel containing the new heat-exchanger, the addition of flow-expanding and flow-contracting turning vanes upstream and downstream of the heat exchanger, respectively, and the addition of fan outlet guide vanes (OGV's). This paper presents an overview of the construction and reactivation testing phases of the project. Important lessons learned during the technical and contract management work are documented.

  10. Structure, Reactivity and Dynamics

    Indian Academy of Sciences (India)

    Understanding structure, reactivity and dynamics is the core issue in chemical ... functional theory (DFT) calculations, molecular dynamics (MD) simulations, light- ... between water and protein oxygen atoms, the superionic conductors which ...

  11. Reactivity feedback coefficients of a material test research reactor fueled with high-density U{sub 3}Si{sub 2} dispersion fuels

    Energy Technology Data Exchange (ETDEWEB)

    Muhammad, Farhan [Department of Nuclear Engineering, Pakistan Institute of Engineering and Applied Sciences, Nilore, Islamabad 45650 (Pakistan)], E-mail: farhan73@hotmail.com; Majid, Asad [Department of Nuclear Engineering, Pakistan Institute of Engineering and Applied Sciences, Nilore, Islamabad 45650 (Pakistan)

    2008-10-15

    The reactivity feedback coefficients of a material test research reactor fueled with high-density U{sub 3}Si{sub 2} dispersion fuels were calculated. For this purpose, the low-density LEU fuel of an MTR was replaced with high-density U{sub 3}Si{sub 2} LEU fuels currently being developed under the RERTR program. Calculations were carried out to find the fuel temperature reactivity coefficient, moderator temperature reactivity coefficient and moderator density reactivity coefficient. Nuclear reactor analysis codes including WIMS-D4 and CITATION were employed to carry out these calculations. It is observed that the average values of fuel temperature reactivity feedback coefficient, moderator temperature reactivity coefficient and moderator density reactivity coefficient from 20 deg. C to 100 deg. C, at the beginning of life, followed the relationships (in units of {delta}k/k x 10{sup -5} K{sup -1}) -2.116 - 0.118 {rho}{sub U}, 0.713 - 37.309/{rho}{sub U} and -12.765 - 34.309/{rho}{sub U}, respectively for 4.0 {<=} {rho}{sub U} (g/cm{sup 3}) {<=} 6.0.

  12. Assessment of impacts at the advanced test reactor as a result of chemical releases at the Idaho Chemical Processing Plant

    International Nuclear Information System (INIS)

    Rood, A.S.

    1991-02-01

    This report provides an assessment of potential impacts at the Advanced Test Reactor Facility (ATR) resulting from accidental chemical spill at the Idaho Chemical Processing Plant (ICPP). Spills postulated to occur at the Lincoln Blvd turnoff to ICPP were also evaluated. Peak and time weighted average concentrations were calculated for receptors at the ATR facility and the Test Reactor Area guard station at a height above ground level of 1.0 m. Calculated concentrations were then compared to the 15 minute averaged Threshold Limit Value - Short Term Exposure Limit (TLV-STEL) and the 30 minute averaged Immediately Dangerous to Life and Health (IDLH) limit. Several different methodologies were used to estimate source strength and dispersion. Fifteen minute time weighted averaged concentrations of hydrofluoric acid and anhydrous ammonia exceeded TLV-STEL values for the cases considered. The IDLH value for these chemicals was not exceeded. Calculated concentrations of ammonium hydroxide, hexone, nitric acid, propane, gasoline, chlorine and liquid nitrogen were all below the TLV-STEL value

  13. Supra-molecular structure and chemical reactivity of cellulose I studied using CP/MAS (sup)13 C-NMR

    CSIR Research Space (South Africa)

    Chunilall, Viren

    2013-08-01

    Full Text Available There are a few traditional methods of analysing the chemical properties of cellulose I. Some of these methods include the Permanganate number determination, which is used to obtain the lignin content of the pulp [12]. The acid insoluble lignin content... – Fundamental Aspects 88 [10] Fengel D, Wegener G. Wood Chemistry, Ultrastructure, Reactions, Walter de Gruyter; 1984. [11] Uhlmann T. Ullmann's encyclopedia of industrial chemistry. Paper and Pulp. 1991; 18 (A). [12] Permanganate number of pulp, Tappi T...

  14. Single and double carbon vacancies in pyrene as first models for graphene defects: A survey of the chemical reactivity toward hydrogen

    Science.gov (United States)

    Nieman, Reed; Das, Anita; Aquino, Adélia J. A.; Amorim, Rodrigo G.; Machado, Francisco B. C.; Lischka, Hans

    2017-01-01

    Graphene is regarded as one of the most promising materials for nanoelectronics applications. Defects play an important role in modulating its electronic properties and also enhance its chemical reactivity. In this work the reactivity of single vacancies (SV) and double vacancies (DV) in reaction with a hydrogen atom Hr is studied. Because of the complicated open shell electronic structures of these defects due to dangling bonds, multireference configuration interaction (MRCI) methods are being used in combination with a previously developed defect model based on pyrene. Comparison of the stability of products derived from Csbnd Hr bond formation with different carbon atoms of the different polyaromatic hydrocarbons is made. In the single vacancy case the most stable structure is the one where the incoming hydrogen is bound to the carbon atom carrying the dangling bond. However, stable Csbnd Hr bonded structures are also observed in the five-membered ring of the single vacancy. In the double vacancy, most stable bonding of the reactant Hr atom is found in the five-membered rings. In total, Csbnd Hr bonds, corresponding to local energy minimum structures, are formed with all carbon atoms in the different defect systems and the pyrene itself. Reaction profiles for the four lowest electronic states show in the case of a single vacancy a complex picture of curve crossings and avoided crossings which will give rise to a complex nonadiabatic reaction dynamics involving several electronic states.

  15. Atmospheric photochemical reactivity and ozone production at two sites in Hong Kong: Application of a Master Chemical Mechanism-photochemical box model

    Science.gov (United States)

    Ling, Z. H.; Guo, H.; Lam, S. H. M.; Saunders, S. M.; Wang, T.

    2014-09-01

    A photochemical box model incorporating the Master Chemical Mechanism (v3.2), constrained with a full suite of measurements, was developed to investigate the photochemical reactivity of volatile organic compounds at a semirural site (Mount Tai Mo Shan (TMS)) and an urban site (Tsuen Wan (TW)) in Hong Kong. The levels of ozone (O3) and its precursors, and the magnitudes of the reactivity of O3 precursors, revealed significant differences in the photochemistry at the two sites. Simulated peak hydroperoxyl radical (HO2) mixing ratios were similar at TW and TMS (p = 0.05), while the simulated hydroxyl radical (OH) mixing ratios were much higher at TW (p TMS, but at TW, both HCHO and O3 photolyses were found to be major contributors. By contrast, radical-radical reactions governed HOx radical losses at TMS, while at TW, the OH + NO2 reaction was found to dominate in the morning and the radical-radical reactions at noon. Overall, the conversion of NO to NO2 by HO2 dictated the O3 production at the two sites, while O3 destruction was dominated by the OH + NO2 reaction at TW, and at TMS, O3 photolysis and the O3 + HO2 reaction were the major mechanisms. The longer OH chain length at TMS indicated that more O3 was produced for each radical that was generated at this site.

  16. Reactive transport modeling of chemical and isotope data to identify degradation processes of chlorinated ethenes in a diffusion-dominated media

    DEFF Research Database (Denmark)

    Chambon, Julie Claire Claudia; Damgaard, Ida; Jeannottat, Simon

    . Degradation and transport processes of chlorinated ethenes are not well understood in such geological settings, therefore risk assessment and remediation at these sites are particularly challenging. In this work, a combined approach of chemical and isotope analysis on core samples, and reactive transport...... the source zone (between 6 and 12 mbs). Concentrations and stable isotope ratios of the mother compounds and their daughter products, as well as redox parameters, fatty acids and microbial data, were analyzed with discrete sub-sampling along the cores. More samples (each 5 mm) were collected around...... of dechlorination and degradation pathways (biotic reductive dechlorination or abiotic β-elimination with iron minerals) in three core profiles. The model includes diffusion in the matrix, sequential reductive dechlorination, abiotic degradation, isotope fractionation due to degradation and due to diffusion...

  17. Reduction in size of bottom-mounted reactivity control mechanism of research reactor for seismic qualification test

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Jongoh; Kim, Gyeongho; Yoo, Yeonsik; Cho, Yeonggarp; Kim, Jongin [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2013-07-01

    A new research reactor employing bottom-mounted reactivity control mechanism (RCM) is under development and its safety function which is a shutdown of the reactor under earthquake events should be verified through a test. However, the real system is too heavy to be excited artificially, and hence the size of a test rig should be reduced somehow. As a preliminary study for development of a seismic test rig, this paper presents how to reduce the length of an extension shaft which is a main component of RCM while it maintains dynamic characteristics of the real system. In this paper, instead of reduction in length of the shaft, the inner/outer radius of the shaft and water gap size between the shaft and its guide tube will be modified in order to match its natural frequency and displacement due to seismic excitation to those of the real system. Furthermore, a proper mass which does not increase the stiffness will be inserted into the hollow shaft. Then, dynamic equation was derived for the beam model and an optimization problem was defined and solved. The result shows that the design modification is reasonable for description of dynamic characteristics of the real system under earthquake events.

  18. Pollen food allergy syndrome in Turkey: Clinical characteristics and evaluation of its association with skin test reactivity to pollens.

    Science.gov (United States)

    Özdemir, Seςil Kepil; Özgüςlü, Selcan

    2017-09-17

    There is limited data regarding pollen food allergy syndrome (PFAS) in Turkey. To investigate the clinical characteristics and possible risk factors of PFAS in Turkey, and to evaluate if there was an association between skin test reactivity to pollens and presence of PFAS. A total of 254 consecutive adult patients with pollen sensitivity were prospectively recruited. Patients were interviewed with a questionnaire including a list of pollen-associated foods. Patients were classified as having PFAS if they reported clear allergic symptoms compatible with PFAS. All participants underwent skin prick tests (SPT) to a panel of common aeroallergens, prick-to-prick tests with culprit fresh foods were performed in patients who gave consent. Self-reported PFAS was observed in 49 patients (19.3%). The most common culprit foods were kiwi, peach, tomato, melon and watermelon. Multiple logistic regression analysis showed that potential risk factors for PFAS were having asthma (OR=2.392, P=0.044) and tree pollen sensitization (OR=2.904, P=0.004). There were no significant differences in the SPT wheal sizes to individual pollen extracts between patients with and without PFAS with a positive SPT result for that pollen extract (P> 0.05). PFAS is frequent in pollen sensitized adults in Turkey. The most commonly implicated foods are kiwi, peach,tomato, melon and watermelon, in our geographical region. SPT wheal sizes to pollen extracts seems to be similar in patients with and without PFAS.

  19. Reduction in size of bottom-mounted reactivity control mechanism of research reactor for seismic qualification test

    International Nuclear Information System (INIS)

    Sun, Jongoh; Kim, Gyeongho; Yoo, Yeonsik; Cho, Yeonggarp; Kim, Jongin

    2013-01-01

    A new research reactor employing bottom-mounted reactivity control mechanism (RCM) is under development and its safety function which is a shutdown of the reactor under earthquake events should be verified through a test. However, the real system is too heavy to be excited artificially, and hence the size of a test rig should be reduced somehow. As a preliminary study for development of a seismic test rig, this paper presents how to reduce the length of an extension shaft which is a main component of RCM while it maintains dynamic characteristics of the real system. In this paper, instead of reduction in length of the shaft, the inner/outer radius of the shaft and water gap size between the shaft and its guide tube will be modified in order to match its natural frequency and displacement due to seismic excitation to those of the real system. Furthermore, a proper mass which does not increase the stiffness will be inserted into the hollow shaft. Then, dynamic equation was derived for the beam model and an optimization problem was defined and solved. The result shows that the design modification is reasonable for description of dynamic characteristics of the real system under earthquake events

  20. A quantum chemical study of the reactivity of acetaminophen (paracetamol) toxic metabolite N-acetyl-p-benzoquinone imine with deoxyguanosine and glutathione.

    Science.gov (United States)

    Klopčič, Ivana; Poberžnik, Matic; Mavri, Janez; Dolenc, Marija Sollner

    2015-12-05

    Acetaminophen (APAP) forms some reactive metabolites that can react with DNA. APAP is a potentially genotoxic drug and is classified as a Group 3 drug according to International Agency for Research on Cancer (IARC). One of the possible mechanisms of APAP genotoxicity after long term of use is that its reactive quinone imine (QI) metabolite of acetaminophen (NAPQI), can chemically react with DNA after glutathione (GSH) depletion. A quantum chemical study of the reactions between the NAPQI and deoxyguanosine (dG) or GSH was performed. Activation energies (ΔG(ǂ)) for the reactions associated with the 1, 4-Michael addition were calculated on the M062X/6-311++G (d,p) level of theory. We modeled the reaction with dG as a multi-step process. The first step is rate-limiting (ΔG(ǂ) = 26.7 kcal/mol) and consists of formation of a C-N bond between the C3 atom of the QI moiety and the N7 atom of dG. The second step involves proton transfer from the C3 moiety to the nitrogen atom of the QI with ΔG(ǂ) of 13.8 kcal/mol. The depurination reaction that follows has a ΔG(ǂ) of 25.7 kcal/mol. The calculated ΔG(ǂ) for the nucleophilic attack of the deprotonated S atom of GSH on the C3 atom of the NAPQI is 12.9 kcal/mol. Therefore, the QI will react with GSH much faster than with DNA. Our study gives mechanistic insight into the genotoxicity of the APAP metabolite and will be useful for estimating the genotoxic potential of existing drugs with a QI moiety. Our results show that clinical application of APAP is safe, while in the case of severely depleted GSH levels APAP should be administered with caution. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  1. Critical Reflections on the Hydrophobic Effect, its Origins and Manifestation: Water Structure, Chemical Reactivity, Micelles and Gels.

    Directory of Open Access Journals (Sweden)

    Sosale Chandrasekhar

    2017-09-01

    Full Text Available The origins of the Hydrophobic Effect (HE, its biological significance and its experimental basis are critically addressed in this brief review. It is argued that the mechanistic work reported on the HE in recent decades needs to be reassessed, as its conclusions are apparently debatable. Essentially, it is highly inaccurate to view the HE as a repulsive interaction, which is rather an attractive one. It appears inevitable that the HE is indeed a manifestation of the perturbation of the structure of water upon the introduction of hydrocarbon molecules into its interior. There appears to be no other satisfactory explanation for the formation of micellar aggregates and the existence of the critical micelle concentration. Also, the practical significance of the HE on the reactivity of organic compounds (e.g. cycloadditions is severely limited by their minuscule solubility levels, itself a manifestation of the HE! Other related phenomena apparently include the formation of gels and the occurrence of certain esterification reactions in water, which are briefly reviewed from a conceptual viewpoint.

  2. Entropy and chemical change. 1: Characterization of product (and reactant) energy distributions in reactive molecular collisions: Information and enthropy deficiency

    Science.gov (United States)

    Bernstein, R. B.; Levine, R. D.

    1972-01-01

    Optimal means of characterizing the distribution of product energy states resulting from reactive collisions of molecules with restricted distributions of initial states are considered, along with those for characterizing the particular reactant state distribution which yields a given set of product states at a specified total energy. It is suggested to represent the energy-dependence of global-type results in the form of square-faced bar plots, and of data for specific-type experiments as triangular-faced prismatic plots. The essential parameters defining the internal state distribution are isolated, and the information content of such a distribution is put on a quantitative basis. The relationship between the information content, the surprisal, and the entropy of the continuous distribution is established. The concept of an entropy deficiency, which characterizes the specificity of product state formation, is suggested as a useful measure of the deviance from statistical behavior. The degradation of information by experimental averaging is considered, leading to bounds on the entropy deficiency.

  3. Effects of Achyrocline satureioides Inflorescence Extracts against Pathogenic Intestinal Bacteria: Chemical Characterization, In Vitro Tests, and In Vivo Evaluation

    Directory of Open Access Journals (Sweden)

    Karla Suzana Moresco

    2017-01-01

    Full Text Available Three Achyrocline satureioides (AS inflorescences extracts were characterized: (i a freeze-dried extract prepared from the aqueous extractive solution and (ii a freeze-dried and (iii a spray-dried extract prepared from hydroethanol extractive solution (80% ethanol. The chemical profile, antioxidant potential, and antimicrobial activity against intestinal pathogenic bacteria of AS extracts were evaluated. In vitro antioxidant activity was determined by the total reactive antioxidant potential (TRAP assay. In vivo analysis and characterization of intestinal microbiota were performed in male Wistar rats (saline versus treated animals with AS dried extracts by high-throughput sequencing analysis: metabarcoding. Antimicrobial activity was tested in vitro by the disc diffusion tests. Moisture content of the extracts ranged from 10 to 15% and 5.7 to 17 mg kg−1 of fluorine. AS exhibited antioxidant activity, especially in its freeze-dried form which also exhibited a wide spectrum of antimicrobial activity against intestinal pathogenic bacteria greater than those observed by the antibiotic, amoxicillin, when tested against Bacillus cereus and Staphylococcus aureus. Antioxidant and antimicrobial activities of AS extracts seemed to be positively correlated with the present amount of flavonoids. These findings suggest a potential use of AS as a coadjuvant agent for treating bacterial-induced intestinal diseases with high rates of antibiotic resistance.

  4. The social role of C-reactive protein point-of-care testing to guide antibiotic prescription in Northern Thailand.

    Science.gov (United States)

    Haenssgen, Marco J; Charoenboon, Nutcha; Althaus, Thomas; Greer, Rachel C; Intralawan, Daranee; Lubell, Yoel

    2018-04-01

    New and affordable point-of-care testing (POCT) solutions are hoped to guide antibiotic prescription and to help limit antimicrobial resistance (AMR)-especially in low- and middle-income countries where resource constraints often prevent extensive diagnostic testing. Anthropological and sociological research has illuminated the role and impact of rapid point-of-care malaria testing. This paper expands our knowledge about the social implications of non-malarial POCT, using the case study of a C-reactive-protein point-of-care testing (CRP POCT) clinical trial with febrile patients at primary-care-level health centres in Chiang Rai province, northern Thailand. We investigate the social role of CRP POCT through its interactions with (a) the healthcare workers who use it, (b) the patients whose routine care is affected by the test, and (c) the existing patient-health system linkages that might resonate or interfere with CRP POCT. We conduct a thematic analysis of data from 58 purposively sampled pre- and post-intervention patients and healthcare workers in August 2016 and May 2017. We find widespread positive attitudes towards the test among patients and healthcare workers. Patients' views are influenced by an understanding of CRP POCT as a comprehensive blood test that provides specific diagnosis and that corresponds to notions of good care. Healthcare workers use the test to support their negotiations with patients but also to legitimise ethical decisions in an increasingly restrictive antibiotic policy environment. We hypothesise that CRP POCT could entail greater patient adherence to recommended antibiotic treatment, but it could also encourage riskier health behaviour and entail potentially adverse equity implications for patients across generations and socioeconomic strata. Our empirical findings inform the clinical literature on increasingly propagated point-of-care biomarker tests to guide antibiotic prescriptions, and we contribute to the anthropological and

  5. Buffer Chemical Polishing and RF Testing of the 56 MHz SRF Cavity

    Energy Technology Data Exchange (ETDEWEB)

    Burrill,A.

    2009-01-01

    The 56 MHz cavity presents a unique challenge in preparing it for RF testing prior to construction of the cryomodule. This challenge arises due to the physical dimensions and subsequent weight of the cavity, and is further complicated by the coaxial geometry, and the need to properly chemically etch and high pressure rinse the entire inner surface prior to RF testing. To the best of my knowledge, this is the largest all niobium SRF cavity to be chemically etched and subsequently tested in a vertical dewar at 4K, and these processes will be the topic of this technical note.

  6. Steam generator chemical cleaning demonstration test No. 1 in a pot boiler

    International Nuclear Information System (INIS)

    Key, G.L.; Helyer, M.H.

    1981-04-01

    The effectiveness of the Electric Power Research Institute (EPRI Mark I) chemical cleaning solvent process was tested utilizing a 12 tube pot boiler that had previously been fouled and dented under 30 days of high chloride fault chemistry operation. Specifically, the intent of this chemical cleaning test was to: (1) dissolve sludge from the tubesheet, (2) remove non-protective magnetite from dented tube/support crevice regions, and (3) quantify the extent of corrosion of steam generator material during the test. Two laboratory cleaning demonstrations of 191 and 142 hours were performed

  7. 76 FR 38169 - Toxic Substances Control Act Chemical Testing; Receipt of Test Data

    Science.gov (United States)

    2011-06-29

    ... (7405M), Office of Pollution Prevention and Toxics, Environmental Protection Agency, 1200 Pennsylvania... gold leaf, dyeing mixtures, antifreeze mixtures, extraction of resins and waxes, preservative for...: June 21, 2011. Maria J. Doa, Director, Chemical Control Division, Office of Pollution Prevention and...

  8. Testing Dust Control Preparation with Respect to Mine Employee Exposure to Inhalling Chemical Agents

    Directory of Open Access Journals (Sweden)

    Eugeniusz Orszulik

    2013-01-01

    Full Text Available This paper presents the results of tests used in dust hazard prevention for air-water spraying devices in collieries. The purpose of the tests was to evaluate mine employees’ exposure to inhalling chemical agents when the ZWILKOP ZW-10 preparation is used. The paper presents the results of the measurements of concentration, in a mine atmosphere, of the following chemical agents: hazardous substances 2-(2-butoxyethoxyethanol and 2-ethylhexan-1-ol, constituting ingredients of the preparation at mine employees’ workstations. The tests were performed during work related to the mining of coal in inclined drift C31, seam 415/1-2 on the premises of “Borynia-Zofiówka-Jastrzębie” Hard Coal Mine, Jastrzębie-Zdrój, Poland, using the TELESTO mist systems. Using aqueous solutions for the preparation at concentrations of 15 and 20‰ causes no exceedance of the allowable mine air concentrations for the chemical agents tested.

  9. Modeling Chemically Reactive Flow of Sutterby Nanofluid by a Rotating Disk in Presence of Heat Generation/Absorption

    Science.gov (United States)

    Hayat, T.; Ahmad, Salman; Ijaz Khan, M.; Alsaedi, A.

    2018-05-01

    In this article we investigate the flow of Sutterby liquid due to rotating stretchable disk. Mass and heat transport are analyzed through Brownian diffusion and thermophoresis. Further the effects of magnetic field, chemical reaction and heat source are also accounted. We employ transformation procedure to obtain a system of nonlinear ODE’s. This system is numerically solved by Built-in-Shooting method. Impacts of different involved parameter on velocity, temperature and concentration are described. Velocity, concentration and temperature gradients are numerically computed. Obtained results show that velocity is reduced through material parameter. Temperature and concentration are enhanced with thermophoresis parameter.

  10. Testing in power plant construction as well as in the petrochemical and chemical industry

    International Nuclear Information System (INIS)

    Riess, N.; Schittko, H.

    1978-01-01

    In general, the upgrading of requirements for the most different fields of engineering is also characterized by a corresponding effort in testing. In this context especially nondestructive tests of materials are of outstanding importance. In the fields of power plant construction (among others, components for nuclear power plants) as well as petrochemical and chemical industry considered here, almost all nondestructive test methods are applied. This paper discusses not so much theoretical testing problems, but rather test objects as well as specifications and testing equipment. (orig./HP) [de

  11. Qualification test of chemical cleaning for secondary side of steam generator in Qinshan Nuclear Power Plant

    International Nuclear Information System (INIS)

    Zhang Mengqin; Zhang Shufeng; Yu Jinghua; Hou Shufeng

    1997-07-01

    The chemical cleaning technique for removing sludge on the secondary side in Qinshan Nuclear Power Plant has been qualified. The chemical cleaning process will carry out during shutdown refuelling. The qualification test has studied the effect of chemical cleaning agent component, cleaning time on dissolution effectiveness of sludge (Fe 3 O 4 ) and to evaluate corrosion situation of main materials of SG in the cleaning process. The main component of cleaning agent is EDTA. The cleaning temperature is 20∼30 degree C. It is determined that allowable remains amount of cleaning agent (EDTA). The technique of cleaning, rinse, passivation for the chemical cleaning in Qinshan Nuclear Power Plant has been made. The qualification test shown that the technique can dissolve Fe 3 O 4 >1 g/L, the corrosion of materials is in allowable value, the allowable remains of EDTA is <0.01%. The technique character is static, ambient temperature. (9 refs., 12 tabs.)

  12. Annual Report, Fall 2016: Alternative Chemical Cleaning of Radioactive High Level Waste Tanks - Corrosion Test Results

    International Nuclear Information System (INIS)

    Wyrwas, R. B.

    2016-01-01

    The testing presented in this report is in support of the investigation of the Alternative Chemical Cleaning program to aid in developing strategies and technologies to chemically clean radioactive High Level Waste tanks prior to tank closure. The data and conclusions presented here were the examination of the corrosion rates of A285 carbon steel and 304L stainless steel exposed to two proposed chemical cleaning solutions: acidic permanganate (0.18 M nitric acid and 0.05M sodium permanganate) and caustic permanganate. (10 M sodium hydroxide and 0.05M sodium permanganate). These solutions have been proposed as a chemical cleaning solution for the retrieval of actinides in the sludge in the waste tanks, and were tested with both HM and PUREX sludge simulants at a 20:1 ratio.

  13. Annual Report, Fall 2016: Alternative Chemical Cleaning of Radioactive High Level Waste Tanks - Corrosion Test Results

    Energy Technology Data Exchange (ETDEWEB)

    Wyrwas, R. B. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2016-09-01

    The testing presented in this report is in support of the investigation of the Alternative Chemical Cleaning program to aid in developing strategies and technologies to chemically clean radioactive High Level Waste tanks prior to tank closure. The data and conclusions presented here were the examination of the corrosion rates of A285 carbon steel and 304L stainless steel exposed to two proposed chemical cleaning solutions: acidic permanganate (0.18 M nitric acid and 0.05M sodium permanganate) and caustic permanganate. (10 M sodium hydroxide and 0.05M sodium permanganate). These solutions have been proposed as a chemical cleaning solution for the retrieval of actinides in the sludge in the waste tanks, and were tested with both HM and PUREX sludge simulants at a 20:1 ratio.

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

    Science.gov (United States)

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

    2012-10-01

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

  15. 76 FR 38170 - Toxic Substances Control Act Chemical Testing; Receipt of Test Data

    Science.gov (United States)

    2011-06-29

    ... must be visible at all times in the building and returned upon departure. II. Test Data Submissions EPA... required by the applicable standards for the development of test data. 3. Describe the nature of the test.... See note. Chinese Hamster Ovary (CHO) Cells. Activated Sludge Die-away 0275.1. Copyrighted...

  16. Theoretical study of coupling mechanisms between oxygen diffusion, chemical reaction, mechanical stresses in a solid-gas reactive system

    International Nuclear Information System (INIS)

    Creton, N.; Optasanu, V.; Montesin, T.; Garruchet, S.

    2008-01-01

    This paper offers a study of oxygen dissolution into a solid, and its consequences on the mechanical behaviour of the material. In fact, mechanical strains strongly influence the oxidation processes and may be, in some materials, responsible for cracking. To realize this study, mechanical considerations are introduced into the classical diffusion laws. Simulations were made for the particular case of uranium dioxide, which undergoes the chemical fragmentation. According to our simulations, the hypothesis of a compression stress field into the oxidised UO 2 compound near the internal interface is consistent with some oxidation mechanisms of oxidation experimentally observed. More generally, this work will be extended to the simulation to an oxide layer growth on a metallic substrate. (authors)

  17. Enhancement of chemically induced reactive oxygen species production and DNA damage in human SH-SY5Y neuroblastoma cells by 872 MHz radiofrequency radiation

    Energy Technology Data Exchange (ETDEWEB)

    Luukkonen, Jukka [Department of Environmental Science, University of Kuopio, Bioteknia 2, P.O. Box 1627, FI-70211 Kuopio (Finland)], E-mail: Jukka.Luukkonen@uku.fi; Hakulinen, Pasi; Maeki-Paakkanen, Jorma [Department of Environmental Health, National Public Health Institute, P.O. Box 95, FI-70701 Kuopio (Finland); Juutilainen, Jukka; Naarala, Jonne [Department of Environmental Science, University of Kuopio, Bioteknia 2, P.O. Box 1627, FI-70211 Kuopio (Finland)

    2009-03-09

    The objective of the study was to investigate effects of 872 MHz radiofrequency (RF) radiation on intracellular reactive oxygen species (ROS) production and DNA damage at a relatively high SAR value (5 W/kg). The experiments also involved combined exposure to RF radiation and menadione, a chemical inducing intracellular ROS production and DNA damage. The production of ROS was measured using the fluorescent probe dichlorofluorescein and DNA damage was evaluated by the Comet assay. Human SH-SY5Y neuroblastoma cells were exposed to RF radiation for 1 h with or without menadione. Control cultures were sham exposed. Both continuous waves (CW) and a pulsed signal similar to that used in global system for mobile communications (GSM) mobile phones were used. Exposure to the CW RF radiation increased DNA breakage (p < 0.01) in comparison to the cells exposed only to menadione. Comparison of the same groups also showed that ROS level was higher in cells exposed to CW RF radiation at 30 and 60 min after the end of exposure (p < 0.05 and p < 0.01, respectively). No effects of the GSM signal were seen on either ROS production or DNA damage. The results of the present study suggest that 872 MHz CW RF radiation at 5 W/kg might enhance chemically induced ROS production and thus cause secondary DNA damage. However, there is no known mechanism that would explain such effects from CW RF radiation but not from GSM modulated RF radiation at identical SAR.

  18. Enhancement of chemically induced reactive oxygen species production and DNA damage in human SH-SY5Y neuroblastoma cells by 872 MHz radiofrequency radiation

    International Nuclear Information System (INIS)

    Luukkonen, Jukka; Hakulinen, Pasi; Maeki-Paakkanen, Jorma; Juutilainen, Jukka; Naarala, Jonne

    2009-01-01

    The objective of the study was to investigate effects of 872 MHz radiofrequency (RF) radiation on intracellular reactive oxygen species (ROS) production and DNA damage at a relatively high SAR value (5 W/kg). The experiments also involved combined exposure to RF radiation and menadione, a chemical inducing intracellular ROS production and DNA damage. The production of ROS was measured using the fluorescent probe dichlorofluorescein and DNA damage was evaluated by the Comet assay. Human SH-SY5Y neuroblastoma cells were exposed to RF radiation for 1 h with or without menadione. Control cultures were sham exposed. Both continuous waves (CW) and a pulsed signal similar to that used in global system for mobile communications (GSM) mobile phones were used. Exposure to the CW RF radiation increased DNA breakage (p < 0.01) in comparison to the cells exposed only to menadione. Comparison of the same groups also showed that ROS level was higher in cells exposed to CW RF radiation at 30 and 60 min after the end of exposure (p < 0.05 and p < 0.01, respectively). No effects of the GSM signal were seen on either ROS production or DNA damage. The results of the present study suggest that 872 MHz CW RF radiation at 5 W/kg might enhance chemically induced ROS production and thus cause secondary DNA damage. However, there is no known mechanism that would explain such effects from CW RF radiation but not from GSM modulated RF radiation at identical SAR

  19. Combined in vivo and in vitro approach for the characterization of penicillin-specific polyclonal lymphocyte reactivity: tolerance tests with safe penicillins instead of challenge with culprit drugs.

    Science.gov (United States)

    Sachs, B; Al Masaoudi, T; Merk, H F; Erdmann, S

    2004-10-01

    Amino-penicillins are a major cause of delayed-type reactions to penicillins. The aim of this study was to establish a diagnostic approach for the characterization of the individual penicillin-specific polyclonal lymphocyte reactivity in order to detect side chain-specific sensitization to amino-penicillins. Patients can then be advised to undergo a tolerance test with safe penicillins instead of provocation with culprit penicillins for confirmation of penicillin allergy. We investigated penicillin-specific polyclonal lymphocyte reactivity in nine patients with delayed-type reactions to amino-penicillins by a combined in vivo (patch, prick and intracutaneous tests with delayed readings) and in vitro (lymphocyte transformation test, LTT) approach. A combination of LTT and skin tests improved the sensitivity for the characterization of penicillin-specific polyclonal lymphocyte reactivity and allowed the detection of three different patterns of lymphocyte reactivity. Four patients showed a side chain-specific sensitization to amino-penicillins in vivo and in vitro and were advised to undergo tolerance tests with safe penicillins. Two patients agreed and were exposed to parenteral benzyl-penicillin and oral phenoxymethyl-penicillin which they tolerated without complications. These data suggest that a combined in vivo and in vitro approach is helpful for the detection of side chain-specific sensitization to amino-penicillins. Patients with such sensitization are very likely to tolerate safe penicillins, thereby expanding their therapeutic options when antibiotic treatment is required.

  20. Efficacy of a chairside diagnostic test kit for estimation of C-reactive protein levels in periodontal disease.

    Science.gov (United States)

    Nagarale, Girish; Ravindra, S; Thakur, Srinath; Setty, Swati

    2010-10-01

    C-reactive protein [CRP] levels increase to hundreds of mg/mL within hours following infection. Studies have shown that serum CRP levels were elevated in periodontal disease. However, in all the previous studies, CRP levels were measured by using high-sensitivity CRP assay kits with minimal detection limits of 0.1 to 3 mg/L, which was much below the normal value of 10 mg/L. These high-sensitivity CRP assays need a proper laboratory setup, and these methods cannot be used as a routine chair-side test in the dental office. The purpose of this study was to investigate the serum CRP levels in subjects with periodontal disease by using a rapid chair-side diagnostic test kit with a lower detection limit of 6 mg/L and to compare the CRP levels before and after periodontal therapy. A total of 45 systemically healthy subjects were selected for the study. Subjects were divided into three groups: group A: healthy controls, group B: gingivitis, group C: periodontitis. Serum levels of CRP were determined by using a latex slide agglutination method with commercially available kit with lower detection limit of 6 mg/L. CRP was negative in all the 15 subjects in groups A and B at baseline, 7th and 30th day. CRP was positive only in 2 subjects in Group C at baseline and 7th day. Estimation of serum CRP by using a rapid chair-side diagnostic test kit is not of any significance in subjects with periodontitis.

  1. Chemically reactive and naturally convective high speed MHD fluid flow through an oscillatory vertical porous plate with heat and radiation absorption effect

    Directory of Open Access Journals (Sweden)

    S.M. Arifuzzaman

    2018-04-01

    Full Text Available This paper concerns with the modelling of an unsteady natural convective and higher order chemically reactive magnetohydrodynamics (MHD fluid flow with the effect of heat and radiation absorption. The flow is generated through a vertical oscillating porous plate. Boundary layer approximations is carried out to establish a flow model which represents the time dependent momentum, energy and diffusion balance equations. Before being solved numerically, the governing partial differential equations (PDEs were transformed into a set of nonlinear ordinary differential equation (ODEs by using non-similar technique. A very efficient numerical approach solves the obtained nonlinear coupled ODEs so called Explicit Finite Difference Method (EFDM. An algorithm is implemented in Compaq Visual Fortran 6.6a as a solving tool. In addition, the stability and convergence analysis (SCA is examined and shown explicitly. The advantages of SCA is its optimizes the accuracy of system parameters such as Prandtl number (Pr and Schmidt number (Sc.The velocity, temperature and concentration fields in the boundary layer region are studied in detail and the outcomes are shown in graphically with the influence of various pertinent parameters such as Grashof number (Gr, modified Grashof number (Gr, magnetic parameter (M, Darcy number (Da,Prandtl number (Pr, Schmidt number (Sc, radiation (R, heat sink (Q,radiation absorption (Q1, Eckert number (Ec, Dufour number (Du,Soret number (Sr, Schmidt number (Sc, reaction index (P and chemical reaction (Kr. Furthermore, the effect of skin friction coefficient (Cf, Nusselt number (Nu and Sherwood number (Sh are also examined graphically. Keywords: MHD, Oscillating porous plate, Radiation absorption, High order chemical reaction, EFDM

  2. Hybrid graphene oxide/DAB-Am-16 dendrimer: Preparation, characterization chemical reactivity and their electrocatalytic detection of L-Dopamine

    Science.gov (United States)

    Do Carmo, Devaney Ribeiro; Fernandes, Daniela Silvestrini

    2017-09-01

    Graphene oxide (GO) was chemically modified with a poly(propylene)imine Generation 3.0 dendrimer (DAB-Am-16). The characterization, structure and properties of hybrid graphene oxide/DAB-Am-16 dendrimer was studied by Raman spectroscopy, Fourier-Transforming Infrared Spectroscopy (FT-IR), X-Ray Photoelectron Spectroscopic (XPS), X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM) and Thermogravimetric analysis. After functionalized the hybrid material (GOD) can interact with copper and subsequently with hexacyanoferrate (III) ions (GODHCu). The GODHCu incorporated into a graphite paste electrode (20% w/w) was applied to an electrocatalytic detection of neurotransmitter L-dopamine using differential pulse voltammetry. The analytical curve showed a linear response in the concentration range from 1.0 × 10-7 to 1.0 × 10-5 mol L-1 with a corresponding equation Y(A) = 1.706 × 10-5 + 0.862 [L-dopamine] and a correlation coefficient r2 = 0.998. The detection limit was 6.36 × 10-7 mol L-1 with a relative standard deviation of ±4% (n = 3) and an amperometric sensitivity of 0.862 A/mol L-1.

  3. A numerical analysis for non-linear radiation in MHD flow around a cylindrical surface with chemically reactive species

    Directory of Open Access Journals (Sweden)

    Junaid Ahmad Khan

    2018-03-01

    Full Text Available Boundary layer flow around a stretchable rough cylinder is modeled by taking into account boundary slip and transverse magnetic field effects. The main concern is to resolve heat/mass transfer problem considering non-linear radiative heat transfer and temperature/concentration jump aspects. Using conventional similarity approach, the equations of motion and heat transfer are converted into a boundary value problem whose solution is computed by shooting method for broad range of slip coefficients. The proposed numerical scheme appears to improve as the strengths of magnetic field and slip coefficients are enhanced. Axial velocity and temperature are considerably influenced by a parameter M which is inversely proportional to the radius of cylinder. A significant change in temperature profile is depicted for growing wall to ambient temperature ratio. Relevant physical quantities such as wall shear stress, local Nusselt number and local Sherwood number are elucidated in detail. Keywords: Stretchable boundary, Thermal radiation, Chemical reaction, Mathematical modeling, Non-linear differential system, Mass transfer

  4. Chemical dynamics between wells across a time-dependent barrier: Self-similarity in the Lagrangian descriptor and reactive basins.

    Science.gov (United States)

    Junginger, Andrej; Duvenbeck, Lennart; Feldmaier, Matthias; Main, Jörg; Wunner, Günter; Hernandez, Rigoberto

    2017-08-14

    In chemical or physical reaction dynamics, it is essential to distinguish precisely between reactants and products for all times. This task is especially demanding in time-dependent or driven systems because therein the dividing surface (DS) between these states often exhibits a nontrivial time-dependence. The so-called transition state (TS) trajectory has been seen to define a DS which is free of recrossings in a large number of one-dimensional reactions across time-dependent barriers and thus, allows one to determine exact reaction rates. A fundamental challenge to applying this method is the construction of the TS trajectory itself. The minimization of Lagrangian descriptors (LDs) provides a general and powerful scheme to obtain that trajectory even when perturbation theory fails. Both approaches encounter possible breakdowns when the overall potential is bounded, admitting the possibility of returns to the barrier long after the trajectories have reached the product or reactant wells. Such global dynamics cannot be captured by perturbation theory. Meanwhile, in the LD-DS approach, it leads to the emergence of additional local minima which make it difficult to extract the optimal branch associated with the desired TS trajectory. In this work, we illustrate this behavior for a time-dependent double-well potential revealing a self-similar structure of the LD, and we demonstrate how the reflections and side-minima can be addressed by an appropriate modification of the LD associated with the direct rate across the barrier.

  5. Integration of On-Column Chemical Reactions in Protein Characterization by Liquid Chromatography/Mass Spectrometry: Cross-Path Reactive Chromatography.

    Science.gov (United States)

    Pawlowski, Jake W; Carrick, Ian; Kaltashov, Igor A

    2018-01-16

    Profiling of complex proteins by means of mass spectrometry (MS) frequently requires that certain chemical modifications of their covalent structure (e.g., reduction of disulfide bonds), be carried out prior to the MS or MS/MS analysis. Traditionally, these chemical reactions take place in the off-line mode to allow the excess reagents (the majority of which interfere with the MS measurements and degrade the analytical signal) to be removed from the protein solution prior to MS measurements. In addition to a significant increase in the analysis time, chemical reactions may result in a partial or full loss of the protein if the modifications adversely affect its stability, e.g,, making it prone to aggregation. In this work we present a new approach to solving this problem by carrying out the chemical reactions online using the reactive chromatography scheme on a size exclusion chromatography (SEC) platform with MS detection. This is achieved by using a cross-path reaction scheme, i.e., by delaying the protein injection onto the SEC column (with respect to the injection of the reagent plug containing a disulfide-reducing agent), which allows the chemical reactions to be carried out inside the column for a limited (and precisely controlled) period of time, while the two plugs overlap inside the column. The reduced protein elutes separately from the unconsumed reagents, allowing the signal suppression in ESI to be avoided and enabling sensitive MS detection. The new method is used to measure fucosylation levels of a plasma protein haptoglobin at the whole protein level following online reduction of disulfide-linked tetrameric species to monomeric units. The feasibility of top-down fragmentation of disulfide-containing proteins is also demonstrated using β 2 -microglobulin and a monoclonal antibody (mAb). The new online technique is both robust and versatile, as the cross-path scheme can be readily expanded to include multiple reactions in a single experiment (as

  6. Serological cross-reactivity of Trypanosoma cruzi, Ehrlichia canis, Toxoplasma gondii, Neospora caninum and Babesia canis to Leishmania infantum chagasi tests in dogs

    Directory of Open Access Journals (Sweden)

    Maurício Franco Zanette

    2014-01-01

    Full Text Available Introduction: The aim of this study was to evaluate the serological cross-reactivity between Leishmania sp. and other canine pathogens. Methods: Positive serum samples for Ehrlichia canis, Babesia canis, Toxoplasma gondii, Neospora caninum and Trypanosoma cruzi were tested using three serological methods enzyme linked immunosorbent assay (ELISA, indirect immunofluorescent antibody test (IFAT and Kalazar Detect™, for canine visceral leishmaniasis. Results: Of the 57 dog samples tested, 24 (42.1% tested positive using one of the three serological methods: 10/57 (17.5% for ELISA, 11/57 (19.3% for IFAT and 3/57 (5.3% for Kalazar Detect™. Conclusions: Our results demonstrated that the presence of other infectious agents may lead to cross-reactivity on leishmaniasis serological tests.

  7. Host-guest complex of N-(2-chloroethyl), N-nitroso, N‧, N‧ -dicyclohexylsulfamid with β-cyclodextrin: Fluorescence, QTAIM analysis and structure-chemical reactivity

    Science.gov (United States)

    Bensouilah, Nadjia; Fisli, Hassina; Bensouilah, Hamza; Zaater, Sihem; Abdaoui, Mohamed; Boutemeur-Kheddis, Baya

    2017-10-01

    In this work, the inclusion complex of DCY/CENS: N-(2-chloroethyl), N-nitroso, N‧, N‧-dicyclohexylsulfamid and β-cyclodextrin (β-CD) is investigated using the fluorescence spectroscopy, PM3, ONIOM2 and DFT methods. The experimental part reveals that DCY/CENS forms a 1:1 stoichiometric ratio inclusion complex with β-CD. The constant of stability is evaluated using the Benesi-Hildebrand equation. The results of the theoretical optimization showed that the lipophilic fraction of molecule (cyclohexyl group) is inside of β-CD. Accordingly, the Nitroso-Chloroethyl moiety is situated outside the cavity of the macromolecule host. The favorable structure of the optimized complex indicates the existence of weak intermolecular hydrogen bonds and the most important van der Waals (vdW) interactions which are studied on the basis of Natural Bonding Orbital (NBO) analysis. The NBO is employed to compute the electronic donor-acceptor exchanges between drug and β-CD. Furthermore, a detailed topological charge density analysis based on the quantum theory of atoms in molecules (QTAIM), has been accomplished on the most favorable complex using B3LYP/6-31G(d) method. The presence of stabilizing intermolecular hydrogen bonds and van der Waals interactions in the most favorable complex is predicted. Also, the energies of these interactions are estimated with Espinosa's formula. The findings of this investigation reveal that the correlation between the structural parameters and the electronic density is good. Finally, and based on DFT calculations, the reactivity of the interesting molecule in free state was studied and compared with that in the complexed state using chemical potential, global hardness, global softness, electronegativity, electrophilicity and local reactivity descriptors.

  8. Sex differences in salivary cortisol reactivity to the Trier Social Stress Test (TSST): A meta-analysis.

    Science.gov (United States)

    Liu, Jenny J W; Ein, Natalie; Peck, Katlyn; Huang, Vivian; Pruessner, Jens C; Vickers, Kristin

    2017-08-01

    Some, but not all studies using the Trier Social Stress Test (TSST) have demonstrated evidence in support of sex differences in salivary cortisol. The aim of the current meta-analysis is to examine sex differences in salivary cortisol following exposure to the TSST. We further explored the effects of modifications to the TSST protocol and procedural variations as potential moderators. We searched articles published from January, 1993 to February, 2016 in MedLine, PsychINFO, and ProQuest Theses and Dissertations. This meta-analysis is based on 34 studies, with a total sample size of 1350 individuals (640 women and 710 men). Using a random effects model, we found significant heterogeneity in salivary cortisol output across sexes, such that men were observed to have higher cortisol values at peak and recovery following the TSST compared to women. Modifications to the sampling trajectory of cortisol (i.e., duration of acclimation, peak sampling time, and duration of recovery) significantly moderated the heterogeneity across both sexes. Further, there are observed sex differences at various time points of the reactive cortisol following the TSST. Lastly, current results suggest that these sex differences can be, at least in part, attributed to variations in methodological considerations across studies. Future research could advance this line of inquiry by using other methods of analyses (e.g., area under the curve; AUC), in order to better understand the effects of methodological variations and their implications for research design. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. 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.

  10. Project W-314 Polyurea Special Protective Coating (SPC) Test Report Chemical Compatibility and Physical Characteristics Testing

    International Nuclear Information System (INIS)

    MAUSER, R.W.

    2001-01-01

    This Engineering Test report outlines the results obtained from testing polyurea on its decon factor, tank waste compatibility, and adhesion strength when subjected to a high level of gamma radiation. This report is used in conjunction with RPP-7187 Project W-314 Pit Coatings Repair Requirements Analysis, to document the fact polyurea meets the project W-314 requirements contained in HNF-SD-W314-PDS-005 and is therefore an acceptable SPC for use in W-314 pit refurbishments

  11. 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

  12. Test Operations Procedure (TOP) 3-2-609; Chemical Compatibility of Nonmetallic Materials used in Small Arms Systems

    National Research Council Canada - National Science Library

    1999-01-01

    ...) by conditioning them in various chemical solutions. Physical properties of the material to be tested are measured before and after conditioning to determine the degradation attributable to the chemical solution...

  13. Including Bioconcentration Kinetics for the Prioritization and Interpretation of Regulatory Aquatic Toxicity Tests of Highly Hydrophobic Chemicals

    DEFF Research Database (Denmark)

    Kwon, Jung-Hwan; Lee, So-Young; Kang, Hyun-Joong

    2016-01-01

    experiments. In this work, internal concentrations of highly hydrophobic chemicals were predicted for standard acute ecotoxicity tests at three trophic levels, algae, invertebrate, and fish. As demonstrated by comparison with maximum aqueous concentrations at water solubility, chemicals with an octanol...

  14. chemical studies on the reactivity of some organic extractants for extraction and separation of certain elements from aqueous solutions

    International Nuclear Information System (INIS)

    Aly, M.M.I.

    2010-01-01

    Lanthanide elements such as lanthanum and neodymium are important elements in photo-electronic and metallurgical industries as well as in nuclear technology. The main constituents of the spent nuclear fuel are actinides like uranium, thorium and various fission products including lanthanides. The co-ordination compounds of the trivalent lanthanum and neodymium continues to be an active research area, which includes the specific spectroscopic and magnetic properties of rare earth ions and their applications as super molecular device, contrast-enhancing agents in magnetic resonance imaging, optical signal amplifiers and electroluminescent (EL) devices. Hence, the separation and purification of these elements is of great concern. Solvent extraction technique is employed to separate and purify rare earth elements in an industrial scale, but the separation of lanthanum and neodymium is a difficult task, as lanthanide ions exhibit similar chemical and physical properties. They have generally common and stable +3 oxidation state that requires synthesis of certain extractants which are able to extract them from different aqueous solutions. During the last twenty years, different publications have pointed out the remarkable properties of alkyl amide in the field of separation chemistry. These extractants are able to form stable co-ordination compounds with different metallic ions. In this concern, this thesis deals with the synthesis of different amide extractants namely N, N diethylacetoamide (DEAA), N, N Teteraphenyl malonamide (TPMA), N, N diphenylbenzamide (DPBA), N, N' diphenylacetoamide (DPAA), and N, N' Teteraethyl malonamide (TEMA), which were synthesized, characterized and compared with Aliquat-336 in kerosene for extraction and separation of La (III) and Nd (III). The effect of the different parameters affecting the extraction of these metals from aqueous nitric acid medium in the different systems has been studied in terms of shaking time, nitric acid, hydrogen

  15. Steepest-entropy-ascent quantum thermodynamic modeling of the relaxation process of isolated chemically reactive systems using density of states and the concept of hypoequilibrium state

    Science.gov (United States)

    Li, Guanchen; von Spakovsky, Michael R.

    2016-01-01

    This paper presents a study of the nonequilibrium relaxation process of chemically reactive systems using steepest-entropy-ascent quantum thermodynamics (SEAQT). The trajectory of the chemical reaction, i.e., the accessible intermediate states, is predicted and discussed. The prediction is made using a thermodynamic-ensemble approach, which does not require detailed information about the particle mechanics involved (e.g., the collision of particles). Instead, modeling the kinetics and dynamics of the relaxation process is based on the principle of steepest-entropy ascent (SEA) or maximum-entropy production, which suggests a constrained gradient dynamics in state space. The SEAQT framework is based on general definitions for energy and entropy and at least theoretically enables the prediction of the nonequilibrium relaxation of system state at all temporal and spatial scales. However, to make this not just theoretically but computationally possible, the concept of density of states is introduced to simplify the application of the relaxation model, which in effect extends the application of the SEAQT framework even to infinite energy eigenlevel systems. The energy eigenstructure of the reactive system considered here consists of an extremely large number of such levels (on the order of 10130) and yields to the quasicontinuous assumption. The principle of SEA results in a unique trajectory of system thermodynamic state evolution in Hilbert space in the nonequilibrium realm, even far from equilibrium. To describe this trajectory, the concepts of subsystem hypoequilibrium state and temperature are introduced and used to characterize each system-level, nonequilibrium state. This definition of temperature is fundamental rather than phenomenological and is a generalization of the temperature defined at stable equilibrium. In addition, to deal with the large number of energy eigenlevels, the equation of motion is formulated on the basis of the density of states and a set of

  16. Can vaccinia virus be replaced by MVA virus for testing virucidal activity of chemical disinfectants?

    Directory of Open Access Journals (Sweden)

    Rapp Ingrid

    2010-06-01

    Full Text Available Abstract Background Vaccinia virus strain Lister Elstree (VACV is a test virus in the DVV/RKI guidelines as representative of the stable enveloped viruses. Since the potential risk of laboratory-acquired infections with VACV persists and since the adverse effects of vaccination with VACV are described, the replacement of VACV by the modified vaccinia Ankara strain (MVA was studied by testing the activity of different chemical biocides in three German laboratories. Methods The inactivating properties of different chemical biocides (peracetic acid, aldehydes and alcohols were tested in a quantitative suspension test according to the DVV/RKI guideline. All tests were performed with a protein load of 10% fetal calf serum with both viruses in parallel using different concentrations and contact times. Residual virus was determined by endpoint dilution method. Results The chemical biocides exhibited similar virucidal activity against VACV and MVA. In three cases intra-laboratory differences were determined between VACV and MVA - 40% (v/v ethanol and 30% (v/v isopropanol are more active against MVA, whereas MVA seems more stable than VACV when testing with 0.05% glutardialdehyde. Test accuracy across the three participating laboratories was high. Remarkably inter-laboratory differences in the reduction factor were only observed in two cases. Conclusions Our data provide valuable information for the replacement of VACV by MVA for testing chemical biocides and disinfectants. Because MVA does not replicate in humans this would eliminate the potential risk of inadvertent inoculation with vaccinia virus and disease in non-vaccinated laboratory workers.

  17. 40 CFR 230.61 - Chemical, biological, and physical evaluation and testing.

    Science.gov (United States)

    2010-07-01

    ... in § 230.60, that the likelihood of contamination by contaminants is acceptably low, unless the... be obtained from bioassays in lieu of chemical tests. (2) Water column effects. (i) Sediments... in evaluating water column effects. The permitting authority may specify bioassays when such...

  18. Chemical explosions during 1961-1988 at the Semipalatinsk test site

    International Nuclear Information System (INIS)

    Khalturin, V.I.; Rautian, T.G.; Richards, P.G.

    2000-01-01

    The paper gives us a information about the time in the origin, coordinates, magnitudes and energy classes of the 29 chemical explosions, conducted at the Semipalatinsk test site during the soviet time between 1961 and 1988. The estimates of authors, data from Russian official publications, NORSAR and Hagfros observatories were used. (author)

  19. Mode of Action Frameworks in Toxicity Testing and Chemical Risk Assessment

    NARCIS (Netherlands)

    Meek, B.

    2009-01-01

    Recently, legislative mandates worldwide are requiring systematic consideration of much larger numbers of chemicals. This necessitates more efficient and effective toxicity testing, as a basis to be more predictive in a risk assessment context. This in turn requires much more emphasis early in the

  20. Expanding the test set: Chemicals with potential to disrupt mammalian brain development

    Science.gov (United States)

    High-throughput test methods including molecular, cellular, and alternative species-based assays that examine critical events of normal brain development are being developed for detection of developmental neurotoxcants. As new assays are developed, a "training set' of chemicals i...

  1. Phase Equilibrium, Chemical Equilibrium, and a Test of the Third Law: Experiments for Physical Chemistry.

    Science.gov (United States)

    Dannhauser, Walter

    1980-01-01

    Described is an experiment designed to provide an experimental basis for a unifying point of view (utilizing theoretical framework and chemistry laboratory experiments) for physical chemistry students. Three experiments are described: phase equilibrium, chemical equilibrium, and a test of the third law of thermodynamics. (Author/DS)

  2. Biological and chemical tests of contaminated soils to determine bioavailability and environmentally acceptable endpoints (EAE)

    International Nuclear Information System (INIS)

    Montgomery, C.R.; Menzie, C.A.; Pauwells, S.J.

    1995-01-01

    The understanding of the concept of bioavailability of soil contaminants to receptors and its use in supporting the development of EAE is growing but still incomplete. Nonetheless, there is increased awareness of the importance of such data to determine acceptable cleanup levels and achieve timely site closures. This presentation discusses a framework for biological and chemical testing of contaminated soils developed as part of a Gas Research Institute (GRI) project entitled ''Environmentally Acceptable Endpoints in Soil Using a Risk Based Approach to Contaminated Site Management Based on Bioavailability of Chemicals in Soil.'' The presentation reviews the GRI program, and summarizes the findings of the biological and chemical testing section published in the GRI report. The three primary components of the presentation are: (1) defining the concept of bioavailability within the existing risk assessment paradigm, (2) assessing the usefulness of the existing tests to measure bioavailability and test frameworks used to interpret these measurements, and (3) suggesting how a small selection of relevant tests could be incorporated into a flexible testing scheme for soils to address this issue

  3. The testing of thermal-mechanical-hydrological-chemical processes using a large block

    International Nuclear Information System (INIS)

    Lin, W.; Wilder, D.G.; Blink, J.A.; Blair, S.C.; Buscheck, T.A.; Chesnut, D.A.; Glassley, W.E.; Lee, K.; Roberts, J.J.

    1994-01-01

    The radioactive decay heat from nuclear waste packages may, depending on the thermal load, create coupled thermal-mechanical-hydrological-chemical (TMHC) processes in the near-field environment of a repository. A group of tests on a large block (LBT) are planned to provide a timely opportunity to test and calibrate some of the TMHC model concepts. The LBT is advantageous for testing and verifying model concepts because the boundary conditions are controlled, and the block can be characterized before and after the experiment. A block of Topopah Spring tuff of about 3 x 3 x 4.5 m will be sawed and isolated at Fran Ridge, Nevada Test Site. Small blocks of the rock adjacent to the large block will be collected for laboratory testing of some individual thermal-mechanical, hydrological, and chemical processes. A constant load of about 4 MPa will be applied to the top and sides of the large block. The sides will be sealed with moisture and thermal barriers. The large block will be heated with one heater in each borehole and guard heaters on the sides so that a dry-out zone and a condensate zone will exist simultaneously. Temperature, moisture content, pore pressure, chemical composition, stress and displacement will be measured throughout the block during the heating and cool-down phases. The results from the experiments on small blocks and the tests on the large block will provide a better understanding of some concepts of the coupled TMHC processes

  4. Selection of reference soils for chemicals testing in the European Community

    International Nuclear Information System (INIS)

    Kuhnt, G.; Hertling, T.; Schmotz, W.; Vetter, L.; Fraenzle, M.; Geissler, S.; Knabe, I.; Maass, R.; Struckmeyer, A.; Heinrich, U.

    1991-01-01

    Based on an multivariate statistical evaluation of binary and metric data relating to the soil cover of the European Community five regionally representative reference soils (EURO-Soils) have been identified for chemicals testing in the EC. The soil material sampled at representative localities in Italy, Greece, Great Britain, France and Germany was treated and prepared according to OECD Test Guideline 106 and analysed in detail. The homogenised specimens were subject to an EC-wide ring test to evaluate the feasibility of the modified guideline and to validate the physical-chemical amenability of the reference soils for sorption tests. The results proved the validity of the soils selected for assessing the potential behaviour of new chemicals in soil on the basis of a comparative evaluation of the individual test results obtained. In the light of this parametric assessment potential test soils were subsequently identified in the individual EC Member States which correspond as far as possible to the above reference soils in terms of both taxonomy and sorption-relevant properties. (orig.). 164 refs., 30 tabs., 24 figs [de

  5. 78 FR 66700 - Toxic Substances Control Act Chemical Testing; Receipt of Test Data

    Science.gov (United States)

    2013-11-06

    ... additive for food Rat--Up-and-Down processing, and as Procedure. ingredient in aluminum Micronucleus Test... Toxicity to Fish; Acute Toxicity to Daphnia; Toxicity to Algae; Acute Toxicity to Mammals; Bacterial..., cold Study in Zebra Fish set, and sheet-fed (Brachydanio rerio). applications. Acute Toxicity Study in...

  6. Testing the control of mineral supply rates on chemical erosion in the Klamath Mountains

    Science.gov (United States)

    West, N.; Ferrier, K.

    2017-12-01

    The relationship between rates of chemical erosion and mineral supply is central to many problems in Earth science, including the role of tectonics in the global carbon cycle, nutrient supply to soils and streams via soil production, and lithologic controls on landscape evolution. We aim to test the relationship between mineral supply rates and chemical erosion in the forested uplands of the Klamath mountains, along a latitudinal transect of granodioritic plutons that spans an expected gradient in mineral supply rates associated with the geodynamic response to the migration of the Mendocino Triple Junction. We present 10Be-derived erosion rates and Zr-derived chemical depletion factors, as well as bulk soil and rock geochemistry on 10 ridgetops along the transect to test hypotheses about supply-limited and kinetically-limited chemical erosion. Previous studies in this area, comparing basin-averaged erosion rates and modeled uplift rates, suggest this region may be adjusted to an approximate steady state. Our preliminary results suggest that chemical erosion at these sites is influenced by both mineral supply rates and dissolution kinetics.

  7. Calcium oxide/carbon dioxide reactivity in a packed bed reactor of a chemical heat pump for high-temperature gas reactors

    International Nuclear Information System (INIS)

    Kato, Yukitaka; Yamada, Mitsuteru; Kanie, Toshihiro; Yoshizawa, Yoshio

    2001-01-01

    The thermal performance of a chemical heat pump that uses a calcium oxide/carbon dioxide reaction system was discussed as a heat storage system for utilizing heat output from high temperature gas reactors (HTGR). Calcium oxide/carbon dioxide reactivity for the heat pump was measured using a packed bed reactor containing 1.0 kg of reactant. The reactor was capable of storing heat at 900 deg. C by decarbonation of calcium carbonate and generating up to 997 deg. C by carbonation of calcium oxide. The amount of stored heat in the reactor was 800-900 kJ kg -1 . The output temperature of the reactor could be controlled by regulating the carbonation pressure. The thermal storage performance of the reactor was superior to that of conventional sensible heat storage systems. A heat pump using this CaO/CO 2 reactor is expected to contribute to thermal load leveling and to realize highly efficient utilization of HTGR output due to the high heat storage density and high-quality temperature output of the heat pump

  8. Quantum chemical study of the structure, spectroscopy and reactivity of NO+.(H2O)n=1-5 clusters

    Science.gov (United States)

    Linton, Kirsty A.; Wright, Timothy G.; Besley, Nicholas A.

    2018-03-01

    Quantum chemical methods including Møller-Plesset perturbation (MP2) theory and density functional theory (DFT) have been used to study the structure, spectroscopy and reactivity of NO+.(H2O)n=1-5 clusters. MP2/6-311++G** calculations are shown to describe the structure and spectroscopy of the clusters well. DFT calculations with exchange-correlation functionals with a low fraction of Hartree-Fock exchange give a binding energy of NO+.(H2O) that is too high and incorrectly predict the lowest energy structure of NO+.(H2O)2, and this error may be associated with a delocalization of charge onto the water molecule directly binding to NO+. Ab initio molecular dynamics (AIMD) simulations were performed to study the NO+.(H2O)5 H+.(H2O)4 + HONO reaction to investigate the formation of HONO from NO+.(H2O)5. Whether an intracluster reaction to form HONO is observed depends on the level of electronic structure theory used. Of note is that methods that accurately describe the relative energies of the product and reactant clusters did not show reactions on the timescales studied. This suggests that in the upper atmosphere the reaction may occur owing to the energy present in the NO+.(H2O)5 complex following its formation. This article is part of the theme issue `Modern theoretical chemistry'.

  9. Development and Testing of a High Capacity Plasma Chemical Reactor in the Ukraine

    Energy Technology Data Exchange (ETDEWEB)

    Reilly, Raymond W.

    2012-07-30

    This project, Development and Testing of a High Capacity Plasma Chemical Reactor in the Ukraine was established at the Kharkiv Institute of Physics and Technology (KIPT). The associated CRADA was established with Campbell Applied Physics (CAP) located in El Dorado Hills, California. This project extends an earlier project involving both CAP and KIPT conducted under a separate CRADA. The initial project developed the basic Plasma Chemical Reactor (PCR) for generation of ozone gas. This project built upon the technology developed in the first project, greatly enhancing the output of the PCR while also improving reliability and system control.

  10. Aquatic toxicity testing of liquid hydrophobic chemicals – Passive dosing exactly at the saturation limit

    DEFF Research Database (Denmark)

    Stibany, Felix; Nørgaard Schmidt, Stine; Schäffer, Andreas

    2017-01-01

    The aims of the present study were (1) to develop a passive dosing approach for aquatic toxicity testing of liquid substances with very high Kow values and (2) to apply this approach to the model substance dodecylbenzene (DDB, Log Kow = 8.65). The first step was to design a new passive dosing...... format for testing DDB exactly at its saturation limit. Silicone O-rings were saturated by direct immersion in pure liquid DDB, which resulted in swelling of >14%. These saturated O-rings were used to establish and maintain DDB exposure exactly at the saturation limit throughout 72-h algal growth...... at chemical activity of unity was higher than expected relative to a reported hydrophobicity cut-off in toxicity, but lower than expected relative to a reported chemical activity range for baseline toxicity. The present study introduces a new effective approach for toxicity testing of an important group...

  11. Toxicity tests with crustaceans for detecting sublethal effects of potential endocrine disrupting chemicals

    DEFF Research Database (Denmark)

    Wollenberger, Leah

    /antagonistic activity with the ecdysteroid-responsive Drosophila melanogaster BII cell line 6) to draft an OECD guideline proposal for testing of chemicals based on the experimental work performed within this study In preliminary investigations with A. tonsa were studied various parameters related to processes......New and updated test methods to detect and characterise endocrine disrupting chemicals are urgently needed for the purpose of environmental risk assessment. Although endocrine disruption in invertebrates has not been studied as extensive as in vertebrates, in particular in fish, numerous reports...... of the present Ph.D. project were: 1) to develop a fully synthetic saltwater medium suitable for laboratory culturing of marine copepods including their feeding organism as well as for toxicity testing 2) to identify sensitive endpoints related to growth, development and reproduction of the pelagic calanoid...

  12. Demographic, risk factors and motivations among blood donors with reactive serologic tests for syphilis in São Paulo, Brazil.

    Science.gov (United States)

    Ferreira, S C; de Almeida-Neto, C; Nishiya, A S; Oliveira, C D L; Ferreira, J E; Alencar, C S; Levi, J E; Salles, N A; Mendrone, A; Sabino, E C

    2014-06-01

    To identify the demographic characteristics, risk factors and motivations for donating among blood donors with reactive serologic tests for syphilis. Post-donation interviews with syphilis seropositive blood donors improve recruitment and screening strategies. This case-control study compares 75 Venereal Disease Research Laboratory (VDRL) > 8, EIA+ (enzyme immunoassay) and FTA-ABS+ (fluorescent treponemal antibody); 80 VDRL-, EIA+ and FTA-ABS+; and 34 VDRL- and EIA- donors between 2004 and 2009. Donors were assessed by their demographic characteristics, sexual behaviour, history of alcohol and illicit drugs use, and motivations to donate. Donors with VDRL > 8 were more likely to be divorced [AOR = 12·53; 95% confidence interval (CI) 1·30-120·81], to have had more than six sexual partners (AOR=7·1; 95% CI 1·12-44·62) and to report male-male-sex in the past 12 months (AOR=8·18; 95% CI 1·78-37·60). Donors with VDRL-, EIA+ and FTA-ABS+ were less likely to be female (AOR=0·26; 95% CI 0·07-0·96), more likely to be older (AOR=10·2; 95% CI 2·45-42·58 ≥ 39 and illicit drugs use; 30·7% (VDRL > 8) and 12·5% (VDRL-, EIA+ and FTA-ABS+) of donors reported that they had been at risk for HIV infection (P = 0·004). One-third of donors came to the blood bank to help a friend or a relative who needed blood. Although donors exposed to syphilis reported and recognised some high risk behaviour, most were motivated by direct appeal to donate blood. Monitoring the risk profile of blood donors can benefit public health and improve blood safety. © 2014 The Authors. Transfusion Medicine © 2014 British Blood Transfusion Society.

  13. An experimental test of assessment reactivity within a web-based brief alcohol intervention study for college students.

    Science.gov (United States)

    Fazzino, Tera L; Rose, Gail L; Helzer, John E

    2016-01-01

    Web-based brief alcohol intervention (WBI) programs have efficacy in a wide range of college students and have been widely disseminated to universities to address heavy alcohol use. In the majority of efficacy studies, web-based research assessments were conducted before the intervention. Web-based research assessments may elicit reactivity, which could inflate estimates of WBI efficacy. The current study tested whether web-based research assessments conducted in combination with a WBI had additive effects on alcohol use outcomes, compared to a WBI only. Undergraduate students (n=856) from universities in the United States and Canada participated in this online study. Eligible individuals were randomized to complete 1) research assessments+WBI or 2) WBI-only. Alcohol consumption, alcohol-related problems, and protective behaviors were assessed at one-month follow up. Multiple regression using 20 multiply imputed datasets indicated that there were no significant differences at follow up in alcohol use, alcohol-related problems, or protective behaviors used when controlling for variables with theoretical and statistical relevance. A repeated measures analysis of covariance revealed a significant decrease in peak estimated blood alcohol concentration in both groups, but no differential effects by randomized group. There were no significant moderating effects from gender, hazardous alcohol use, or motivation to change drinking. Web-based research assessments combined with a web-based alcohol intervention did not inflate estimates of intervention efficacy when measured within-subjects. Our findings suggest universities may be observing intervention effects similar to those cited in efficacy studies, although effectiveness trials are needed. Copyright © 2015 Elsevier Ltd. All rights reserved.

  14. Assessment of reactivity of three treponemal tests in non-treponemal non-reactive cases from sexually transmitted diseases clinic, antenatal clinic, integrated counselling and testing centre, other different outdoor patient departments/indoor patients of a tertiary care centre and peripheral health clinic attendees

    Directory of Open Access Journals (Sweden)

    M Bala

    2013-01-01

    Full Text Available In India, many state reference centres for sexually transmitted infections perform only a single screening assay for syphilis diagnosis. In this study, Treponema pallidum haemagglutination (TPHA was performed on 1115 Venereal Disease Research Laboratory (VDRL/rapid plasma regain (RPR non-reactive and 107 reactive sera out of 10,489 tested by VDRL/RPR according to the National AIDS Control Organisation syphilis testing protocol. A total of 47 Specimens reactive in TPHA and non-reactive with VDRL test were subjected to fluorescent treponemal antibody absorption and enzyme-immunoassay. Seroprevalence considering both VDRL and TPHA positivity was highest (4.4% in sexually transmitted diseases clinic attendees than in other subject groups. Positivity by two treponemal tests in 24 (2.2% cases non-reactive by VDRL/RPR was representative of the fully treated patients or latent or late syphilis cases. The findings highlight that a suitable treponemal confirmatory test should be performed in all the diagnostic laboratories.

  15. A computational environment for creating and testing reduced chemical kinetic mechanisms

    Energy Technology Data Exchange (ETDEWEB)

    Montgomery, C.J.; Swensen, D.A.; Harding, T.V.; Cremer, M.A.; Bockelie, M.J. [Reaction Engineering International, Salt Lake City, UT (USA)

    2002-02-01

    This paper describes software called computer assisted reduced mechanism problem solving environment (CARM-PSE) that gives the engineer the ability to rapidly set up, run and examine large numbers of problems comparing detailed and reduced (approximate) chemistry. CARM-PSE integrates the automatic chemical mechanism reduction code CARM and the codes that simulate perfectly stirred reactors and plug flow reactors into a user-friendly computational environment. CARM-PSE gives the combustion engineer the ability to easily test chemical approximations over many hundreds of combinations of inputs in a multidimensional parameter space. The demonstration problems compare detailed and reduced chemical kinetic calculations for methane-air combustion, including nitrogen oxide formation, in a stirred reactor and selective non-catalytic reduction of NOx, in coal combustion flue gas.

  16. Toxicity testing of chemical mixtures: some general aspects and need of international guidelines.

    Science.gov (United States)

    Kappus, H; Yang, R S

    1996-01-01

    The topics discussed by the Working Group on Toxicity Testing of Chemical Mixtures included the following (1) the study designs and results from two real-life exposure scenarios as additional information to the various investigations reported at the conference; (2) the need to take into consideration low-level, long-term exposure (i.e. mimicking human exposure conditions) as well as the issue of limited resources in experimental toxicology studies; (3) the importance of exploring alternative and predictive toxicology methodologies to minimize animal use and to conserve resources; (4) the realization that interactive toxicity should include the consideration of physical and biological agents in addition to chemicals. Two specific studies reported at the conference were also discussed. A number of recommendations were made concerning the planning and implementation of toxicology studies on chemical mixtures.

  17. The testing of materials within the purview of the laws concerning the control of chemical substances

    International Nuclear Information System (INIS)

    Bosselmann, K.; Linden, W.

    1989-01-01

    The main approach adopted for this book is the question of whether and to what extent the commercially available chemical products (ranging from foodstuffs and drugs to pesticides and similar pollutants) have been assessed for environmental and health safety prior to release. The relevant existing laws concerning the testing and characterisation of substances are analysed and compared with a view to the major environmental principle, to prevent chemicals-induced hazards to health and the environment. The book reviews the following laws (and their implementing provisions): law on chemical substances, pesticides, fertilisers, drugs, detergents, leaded petrol, food and feedstuffs, explosives, and transport of hazardous materials. Environmentally significant laws reviewed include the waste management act, the atomic energy act (non-recycable wastes, plutonium, tritium), the water management act, and the act for protection against harmful effects on the environment. (orig./HP) [de

  18. Design and analysis of hot internals for the reactivity control and reserve shutdown units under test at the helium test facility - HTR2008-58159

    International Nuclear Information System (INIS)

    Beyer, E. J. J.; Craig, K. J.

    2008-01-01

    This paper describes the design process followed by Westinghouse Electric South Africa for the insertion of hot internals into the Reactivity Control System (RCS) and Reserve Shutdown System (RSS) Units Under Test (UUTs) at the Helium Test Facility (HTF) at Pelindaba (South Africa)). The aim of the UUTs is to allow the validation of the high temperature operation of the RCS and RSS systems for implementation into the proposed Demonstration Power Plant of the PBMR. The units use electrical heaters to obtain pebble-bed reactor thermal conditions for both the control rods and small absorber spheres (SAS) under a pressurized helium environment. Design challenges include providing for strength under elevated temperatures (900 deg. C maximum); pressure boundary integrity (9 MPa maximum); separation of different volumes (representing core barrel, reactor citadel and other Reactor Pressure Vessel (RPV) volumes); thermal protection of carbon steel vessels by using thermal insulation; allowing for diverse thermal expansion coefficients of different materials; allowing for de-pressurization events within the insulation and internals having access for temperature, pressure, stress and proximity sensors and electrical wiring through high pressure penetrations; and provision for assembly of the hot internals both on and off-site. thermal analyses using Computational Fluid Dynamics (CFD) were performed to evaluate both worst-case and operational conditions of the UUTs. Factors that were considered include thermal insulation properties, heat transfer modes (internal radiation, external radiation and natural convection, forced internal convection for cooling) and operating pressure (ranging from 1 to 9 MPa). The thermal design uses elements originally proposed for hot gas duct design. The results obtained show that the proposed design satisfies ASME VIII requirements of the pressure boundary and that all challenges are successfully met. (authors)

  19. REACTIVITY AND ENDOGENOUS INTOXICATION CELLULAR TESTS OF THE FIRST TIME DIAGNOSTED SOCIALLY ADOPTED PATIENTS WITH INFILTRATIVE LUNG TUBERCULOSIS

    Directory of Open Access Journals (Sweden)

    A. V. Mordyk

    2015-01-01

    Full Text Available The purpose of the research was to assess the endogenous intoxication degree and reactivity condition of an organism by calculation the blood leukocyte indexes and their influence assessment for the outcome of first time diagnosed infiltrative lung tuberculosis for the revealed socially safe patients. Case-records of 260 patients were analysed retrospectively. Inclusion criteria were: first time diagnosed and confirmed diagnosis of infiltrative lungs tuberculosis; age at least 18 years; socially adopted patients (the patients taking official or informal work place, the constant income in a family, a residence, a registration. Exception criteria were: extra pulmonary or other forms of lung tuberculosis at the patient; existence of a serious somatic illness; HIV infection; existence of malignant new growths; mental diseases; the social disadaptation (homeless persons who aren’t working, released from jails or being under examination, abusing alcohol in the form of hard drinkings and accepting drugs. All patients included in research were divided into two groups: first (main — patients with a failure in quantity the 66, second (group of comparison — patients with a favourable outcome of infiltrative tuberculosis of lungs, in number of 194. Failure criterion was the existence (preservation of a disintegration lung cavity confirmed by the last X-ray picture. According patients blood test results the intoxication leukocyte index (ILI, with Kalf-Kalif formula, an blood leukocytes shift index (BLSI, an organism resistance index (ORI, a Dashtayants nuclear index was carried out. Followly the Spirmen correlation analysis with Statistica 6.0 software package was estimated. As a result of research the following data were obtained. The Dashtayants nuclear index high level at primary blood test has the strongest impact on development of infiltrative lungs tuberculosis failure in patients; the ILI and BLSI high levels at the time of the beginning of

  20. In vitro chemical and cellular tests applied to uranium trioxide with different hydration states

    International Nuclear Information System (INIS)

    Ansoborlo, E.; Chalabreysse, J.; Henge-Napoli, M.H.; Pujol, E.

    1992-01-01

    A simple and rapid in vitro chemical solubility test applicable to industrial uranium trioxide (UO 3 ) was developed together with two in vitro cellular tests using rat alveolar macrophages maintained either in gas phase or in alginate beads at 37 degrees C. Industrial UO 3 was characterized by particle size, X-ray, and IR spectra, and chemical transformation (e.g., aging and hydration of the dust) was also studied. Solvents used for the in vitro chemical solubility study included carbonates, citrates, phosphates, water, Eagle's basal medium, and Gamble's solution (simulated lung fluid), alone, with oxygen, or with superoxide ions. Results, expressed in terms of the half-time of dissolution, according to International Commission on Radiological Protection (ICRP) classification (D,W,Y), varied for different hydration states of UO 3 , showing a lower solubility of hydrated UO 3 in solvents compared to basic UO 3 or UO 3 heated at 450 degrees C. Two in vitro cellular tests on cultured rat alveolar macrophages (cells maintained in gas phase and cells immobilized in alginate beads) were used on the same UO 3 samples and generally showed a lower solution transfer rate in the presence of macrophages than in the culture medium alone. The results of in vitro chemical and cellular tests were compared, with four main conclusions; a good reproducibility of the three tests in Eagle's basal medium of the effect of hydration state on solubility, the classification of UO 3 in terms of ICRP solubility criteria, and the ability of macrophoges to decrease uranium solubility in medium. 16 refs., 3 figs., 4 tabs

  1. Mycobacterium tuberculosis epitope-specific interferon-g production in healthy Brazilians reactive and non-reactive to tuberculin skin test

    Directory of Open Access Journals (Sweden)

    Bosco Christiano Maciel da Silva

    2014-12-01

    Full Text Available The interferon (IFN-γ response to peptides can be a useful diagnostic marker of Mycobacterium tuberculosis (MTB latent infection. We identified promiscuous and potentially protective CD4+ T-cell epitopes from the most conserved regions of MTB antigenic proteins by scanning the MTB antigenic proteins GroEL2, phosphate-binding protein 1 precursor and 19 kDa antigen with the TEPITOPE algorithm. Seven peptide sequences predicted to bind to multiple human leukocyte antigen (HLA-DR molecules were synthesised and tested with IFN-γ enzyme-linked immunospot (ELISPOT assays using peripheral blood mononuclear cells (PBMCs from 16 Mantoux tuberculin skin test (TST-positive and 16 TST-negative healthy donors. Eighty-eight percent of TST-positive donors responded to at least one of the peptides, compared to 25% of TST-negative donors. Each individual peptide induced IFN-γ production by PBMCs from at least 31% of the TST-positive donors. The magnitude of the response against all peptides was 182 ± 230 x 106 IFN-γ spot forming cells (SFC among TST-positive donors and 36 ± 62 x 106 SFC among TST-negative donors (p = 0.007. The response to GroEL2 (463-477 was only observed in the TST-positive group. This combination of novel MTB CD4 T-cell epitopes should be tested in a larger cohort of individuals with latent tuberculosis (TB to evaluate its potential to diagnose latent TB and it may be included in ELISPOT-based IFN-γ assays to identify individuals with this condition.

  2. Potential energy profile, structural, vibrational and reactivity descriptors of trans-2-methoxycinnamic acid by FTIR, FT-Raman and quantum chemical studies

    Science.gov (United States)

    Arjunan, V.; Anitha, R.; Thenmozhi, S.; Marchewka, M. K.; Mohan, S.

    2016-06-01

    The stable conformers of trans-2-methoxycinnamic acid (trans-2MCA) are determined by potential energy profile analysis. The energies of the s-cis and s-trans conformers of trans-2MCA determined by B3LYP/cc-pVTZ method are -612.9788331 Hartrees and -612.9780953 Hartrees, respectively. The vibrational and electronic investigations of the stable s-cis and s-trans conformers of trans-2-methoxycinnamic acid have been carried out extensively with FTIR and FT-Raman spectral techniques. The s-cis conformer (I) with a (C16-C17-C18-O19) dihedral angle equal to 0° is found to be more favoured relative to the one s-trans (II) with (C16-C17-C18-O19) = 180°, possibly due to delocalization, hydrogen bonding and steric repulsion effects between the methoxy and acrylic acid groups. The DFT studies are performed with B3LYP method by utilizing 6-311++G** and cc-pVTZ basis sets to determine the structure, thermodynamic properties, vibrational characteristics and chemical shifts of the compound. The total dipole moments of the conformers determined by B3LYP/cc-pVTZ method are 3.35 D and 4.87 D for s-cis and s-trans, respectively. It reveals the higher polarity of s-trans conformer of trans-2MCA molecule. The electronic and steric influence of the methoxy group on the skeletal frequencies has been analysed. The energies of the frontier molecular orbitals and the LUMO-HOMO energy gap have been determined. The MEP of s-cis conformer lie in the range +1.374e × 10-2 to -1.374e × 10-2 while for s-trans it is +1.591e × 10-2 to -1.591e × 10-2. The total electron density of s-cis conformer lie in the range +5.273e × 10-2 to -5.273e × 10-2 while for s-trans it is +5.403e × 10-2 to -5.403e × 10-2. The MEP and total electron density shows that the s-cis conformer is less polar, less reactive and more stable than the s-trans conformer. All the reactivity descriptors of the molecule have been discussed. Intramolecular electronic interactions and their stabilisation energies have analysed

  3. Testing the Control of Mineral Supply Rates on Chemical Erosion Rates in the Klamath Mountains

    Science.gov (United States)

    West, N.; Ferrier, K.

    2016-12-01

    The relationship between rates of chemical erosion and mineral supply is central to many problems in Earth science, including how tightly Earth's climate should be coupled to tectonics, how strongly nutrient supply to soils and streams depends on soil production, and how much lithology affects landscape evolution. Despite widespread interest in this relationship, there remains no consensus on how closely coupled chemical erosion rates should be to mineral supply rates. To address this, we have established a network of field sites in the Klamath Mountains along a latitudinal transect that spans an expected gradient in mineral supply rates associated with the geodynamic response to the migration of the Mendocino Triple Junction. Here, we present new measurements of regolith geochemistry and topographic analyses that will be compared with cosmogenic 10Be measurements to test hypotheses about supply-limited and kinetically-limited chemical erosion on granodioritic ridgetops. Previous studies in this area suggest a balance between rock uplift rates and basin wide erosion rates, implying the study ridgetops may have adjusted to an approximate steady state. Preliminary data are consistent with a decrease in chemical depletion fraction (CDF) with increasing ridgetop curvature. To the extent that ridgetop curvature reflects ridgetop erosion rates, this implies that chemical erosion rates at these sites are influenced by both mineral supply rates and dissolution kinetics.

  4. Effects of high density dispersion fuel loading on the uncontrolled reactivity insertion transients of a low enriched uranium fueled material test research reactor

    Energy Technology Data Exchange (ETDEWEB)

    Muhammad, Farhan [Department of Nuclear Engineering, Pakistan Institute of Engineering and Applied Sciences, Nilore, Islamabad 45650 (Pakistan)], E-mail: farhan73@hotmail.com; Majid, Asad [Department of Nuclear Engineering, Pakistan Institute of Engineering and Applied Sciences, Nilore, Islamabad 45650 (Pakistan)

    2009-08-15

    The effects of using high density low enriched uranium on the uncontrolled reactivity insertion transients of a material test research reactor were studied. For this purpose, the low density LEU fuel of an MTR was replaced with high density U-Mo (9w/o) LEU fuels currently being developed under the RERTR program having uranium densities of 6.57 gU/cm{sup 3}, 7.74 gU/cm{sup 3} and 8.57 gU/cm{sup 3}. Simulations were carried out to determine the reactor performance under reactivity insertion transients with totally failed control rods. Ramp reactivities of 0.25$/0.5 s and 1.35$/0.5 s were inserted with reactor operating at full power level of 10 MW. Nuclear reactor analysis code PARET was employed to carry out these calculations. It was observed that when reactivity insertion was 0.25$/0.5 s, the new power level attained increased by 5.8% as uranium density increases from 6.57 gU/cm{sup 3} to 8.90 gU/cm{sup 3}. This results in increased maximum temperatures of fuel, clad and coolant outlet, achieved at the new power level, by 4.7 K, 4.4 K and 2.4 K, respectively. When reactivity insertion was 1.35$/0.5 s, the feedback reactivities were unable to control the reactor which resulted in the bulk boiling of the coolant; the one with the highest fuel density was the first to reach the boiling point.

  5. Chemical decontamination for decommissioning purposes. (Vigorous decontamination tests of steel samples in a special test loop)

    International Nuclear Information System (INIS)

    Bregani, F.; Pascali, R.; Rizzi, R.

    1984-01-01

    The aim of the research activities described was to develop vigorous decontamination techniques for decommissioning purposes, taking into account the cost of treatment of the radwaste, to achieve possibly unrestricted release of the treated components, and to obtain know-how for in situ hard decontamination. The decontamination procedures for strong decontamination have been optimized in static and dynamic tests (DECO-loop). The best values have been found for: (i) hydrochloric acid: 4 to 5% vol. at low temperature, 0.7 to 1% vol. at high temperature (80 0 C); (ii) hydrofluoric plus nitric acid: 1.5% vol. HF + 5% vol. HNO 3 at low temperature; 0.3 to 0.5% vol. HF + 2.5 to 5% vol. HNO 3 at high temperature. High flow rates are not necessary, but a good re-circulation of the solution is needed. The final contamination levels, after total oxide removal, are in accordance with limits indicated for unrestricted release of materials in some countries. The arising of the secondary waste is estimated. Decontamination of a 10 m 2 surface would typically produce 0.5 to 3.0 kg of dry waste, corresponding to 1.6 to 10 kg of concrete conditioned waste

  6. Mixed waste chemical compatibility: A testing program for plastic packaging components

    International Nuclear Information System (INIS)

    Nigrey, P.J.

    1995-01-01

    The purpose of hazardous and radioactive materials packaging is to enable these materials to be transported without posing a threat to the health or property of the general public. To achieve this aim, regulations in the United States have been written establishing general design requirements for such packagings. While no regulations have been written specifically for mixed waste packaging, regulations for the constituents of mixed wastes, i.e., hazardous and radioactive substances, have been codified by the US Department of Transportation (DOT, 49 CFR 173) and the US Nuclear Regulatory Commission (NRC, 10 CFR 71). The design requirements for both hazardous [49 CFR 173.24 (e)(1)] and radioactive [49 CFR 173.412 (g)] materials packaging specify packaging compatibility, i.e., that the materials of the packaging at sign d any contents be chemically compatible with each other. Furthermore, Type A [49 CFR 173.412 (g)] and Type B (10 CFR 71.43) packaging design requirements stipulate that there be no significant chemical, galvanic, or other reaction between the materials and contents of the package. Based on these requirements, a Chemical Compatibility Testing Program was developed in the Transportation Systems Department at Sandia National Laboratories (SNL). The program attempts to assure any regulatory body that the issue of packaging material compatibility towards hazardous and radioactive materials has been addressed. This program has been described in considerable detail in an internal SNL document, the Chemical Compatibility Test Plan ampersand Procedure Report (Nigrey 1993)

  7. Correlation of Chemical and Physical Test Data for the Environmental Ageing of Tefzel (ETFE)

    Science.gov (United States)

    Morgan, G. J.; Campion, R. P.

    1996-01-01

    In a similar approach to that used for the previously issued correlation report for Coflon (CAPP/M.10), this report aims to identify any correlations between mechanical property changes and chemical/morphological changes for Tefzel, using information supplied in other MERL and TRI project reports (plus latest data which will be included in final reports for Phase 1). Differences identified with Coflon behaviour will be of scientific interest as well as appropriate to project applications, as Tefzel and Coflon are chemical isomers. Owing to the considerable chemical resistance of Tefzel, much of its testing so far has been based on mechanical properties. Where changes have occurred, chemical analysis can now be targeted more effectively. Relevant test data collated here include: tensile modulus and related properties, permeation coefficients, % crystallinity, and other observations where significant. Fluids based on methanol and amine (Fluid G), a mixture of methane, carbon dioxide and hydrogen sulphide gases plus an aqueous amine solution (Fluid F), and an aromatic oil mix of heptane, cyclohexane, toluene and I-propanol (Fluid 1) have affected Tefzel to varying degrees, and are discussed in some detail herein.

  8. Correlation of Chemical and Physical Test Data for the Environmental Ageing of Tefzel (ETFE). Revised

    Science.gov (United States)

    Morgan, G. J.; Campion, R. P.

    1997-01-01

    In a similar approach to that used for the previously issued correlation report for Coflon (CAPP/M.10), this report aims to identify any correlations between mechanical property changes and chemical/morphological changes for Tefzel, using information supplied in other MERL and TRI project reports. Differences identified with Coflon behaviour will be of scientific interest as well as appropriate to project applications, as Tefzel and Coflon are chemical isomers. Owing to the considerable chemical resistance of Tefzel, much of its testing so far has been based on mechanical properties. Where changes have occurred, chemical analysis can now be targeted more effectively. Relevant test data collated here include: tensile modulus and related properties, permeation coefficients, % crystallinity, some crack growth resistance measurements, and other observations where significant. Fluids based on methanol and amine (Fluid G), a mixture of methane, carbon dioxide and hydrogen sulphide gases plus an aqueous amine solution (Fluid F), and an aromatic oil mix of heptane, cyclohexane, toluene and 1-propanol (Fluid I) have affected Tefzel to varying degrees, and are discussed in some detail herein.

  9. Single-well reactive tracer test and stable isotope analysis for determination of microbial activity in a fast hydrocarbon-contaminated aquifer

    International Nuclear Information System (INIS)

    Burbery, L.; Cassiani, G.; Andreotti, G.; Ricchiuto, T.; Semple, K.T.

    2004-01-01

    Single-well reactive tracer tests, such as the push-pull test are useful tools for characterising in-situ bioattenuation processes in contaminated aquifers. However, the analytical models that are used to interpret push-pull data may be over-simplified, and potentially overlook important processes responsible for the frequent discrepancy between predicted and observed results obtained from push-pull tests. In this study, the limitations underlying the push-pull test methodology were investigated and were supported with results from a push-pull test conducted in a sulphate-reducing aquifer contaminated by crude oil. Poor ( 20% mass recoveries were achieved. Push-pull test data collected from sulphate-reducing aquifers indicate that the assumption of a well-mixed batch reactor system is incorrect and that reaction rates obtained from push-pull tests in such systems may be affected by the extraction regime implemented. Evidence of microbial respiration of the reactive tracer was provided by stable sulphur isotope analysis, from which an isotope fractionation factor of +9.9±8.1%o was estimated. The stable isotope data support the argument that reaction rates calculated using push-pull tests are not uniformly distributed in space and time and are likely to be influenced by heterogeneities in the flow field. - Reaction rates calculated by push-pull tests are not uniformly distributed in time and space

  10. Enhanced durability and reactivity for zinc ferrite desulfurization sorbent. Volume 1, Bench-scale testing and analysis

    Energy Technology Data Exchange (ETDEWEB)

    Jha, M.C.; Berggren, M.H.

    1989-05-02

    AMAX Research & Development Center (AMAX R&D) has been investigating methods for enhancing the reactivity and durability of the zinc ferrite desulfurization sorbent. Zinc ferrite sorbents are intended for use in desulfurization of hot coal gas in integrated gasification combined cycle (IGCC) or molten carbonate fuel cell (MCFC) applications. For the present program, the reactivity of the sorbent may be defined as its sulfur sorption capacity at the breakthrough point and at saturation in a bench-scale, fixed-bed reactor. Durability may be defined as the ability of the sorbent to maintain important physical characteristics such As size, strength, and specific surface area during 10 cycles of sulfidation and oxidation.

  11. Biodecolorization and biodegradation of Reactive Blue by ...

    African Journals Online (AJOL)

    SERVER

    2007-06-18

    Jun 18, 2007 ... Aspergillus sp. effectively decolorized Reactive Blue and other structurally different synthetic dyes. Agitation was found to be an important ... Few chemically different dyes such as Reactive Black (75%), Reactive Yellow (70%),. Reactive Red (33%) and ..... Degradation of azo dyes by the lignin degrading ...

  12. Influence of chemicals on clays. Pt. 2. Structure and solidity tests

    Energy Technology Data Exchange (ETDEWEB)

    Komodromos, A; Goettner, J J

    1988-12-01

    Continuing an earlier contribution, this article describes tests carried through to verify in how far chemicals in dumped wastes are capable of impairing clay as sealing of the bottom of sanitary landfills. The following was found: Non-polar organic solvents should not be deposited in sanitary landfills with clay as a sealing layer at the bottom, and mineral sealings should be thicker than 60 cms if reactions cannot be excluded with certainty.

  13. Chemical Composition Analysis and Product Consistency Tests of the ORP Phase 5 Nepheline Study Glasses

    Energy Technology Data Exchange (ETDEWEB)

    Fox, K. M. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Edwards, T. B. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Caldwell, M. E. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Riley, W. T. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2018-02-01

    In this report, the Savannah River National Laboratory (SRNL) provides chemical analyses and Product Consistency Test (PCT) results for a series of simulated high-level waste glass compositions fabricated by the Pacific Northwest National Laboratory (PNNL). These data will be used in the development of improved models for the prediction of nepheline crystallization in support of the Hanford Tank Waste Treatment and Immobilization Plant (WTP).

  14. Production of chemically reactive radioactive ion beams through on-line separation; Production de faisceaux d'ions radioactifs chimiquement reactifs par separation en ligne

    Energy Technology Data Exchange (ETDEWEB)

    Joinet, A

    2003-10-01

    The ISOL (isotope separation on line) allows the production of secondary radioactive ion beams through spallation or fragmentation or fission reactions that take place in a thick target bombarded by a high intensity primary beam. The challenge is to increase the intensity and purity of the radioactive beam. The optimization of the system target/source requires the right choice of material for the target by taking into account the stability of the material, its reactivity and the ionization method used. The target is an essential part of the system because radioactive elements are generated in it and are released more or less quickly. Tests have been made in order to select the best fitted material for the release of S, Se, Te, Ge and Sn. Materials tested as target filling are: ZrO{sub 2}, Nb, Ti, V,TiO{sub 2}, CeO{sub x}, ThO{sub 2}, C, ZrC{sub 4} and VC). Other molecules such as: COSe, COS, SeS, COTe, GeS, SiS, SnS have been studied to ease the extraction of recoil nuclei (Se, S, Te, Ge and Sn) produced inside the target.

  15. Production of chemically reactive radioactive ion beams through on-line separation; Production de faisceaux d'ions radioactifs chimiquement reactifs par separation en ligne

    Energy Technology Data Exchange (ETDEWEB)

    Joinet, A

    2003-10-01

    The ISOL (isotope separation on line) allows the production of secondary radioactive ion beams through spallation or fragmentation or fission reactions that take place in a thick target bombarded by a high intensity primary beam. The challenge is to increase the intensity and purity of the radioactive beam. The optimization of the system target/source requires the right choice of material for the target by taking into account the stability of the material, its reactivity and the ionization method used. The target is an essential part of the system because radioactive elements are generated in it and are released more or less quickly. Tests have been made in order to select the best fitted material for the release of S, Se, Te, Ge and Sn. Materials tested as target filling are: ZrO{sub 2}, Nb, Ti, V,TiO{sub 2}, CeO{sub x}, ThO{sub 2}, C, ZrC{sub 4} and VC). Other molecules such as: COSe, COS, SeS, COTe, GeS, SiS, SnS have been studied to ease the extraction of recoil nuclei (Se, S, Te, Ge and Sn) produced inside the target.

  16. A randomized controlled trial to test the effect of multispecies probiotics on cognitive reactivity to sad mood

    NARCIS (Netherlands)

    Steenbergen, L.; Sellaro, R.; van Hemert, S.; Bosch, J.A.; Colzato, L.S.

    2015-01-01

    Background: Recent insights into the role of the human microbiota in cognitive and affective functioning have led to the hypothesis that probiotic supplementation may act as an adjuvant strategy to ameliorate or prevent depression. Objective: Heightened cognitive reactivity to normal, transient

  17. Performance test of multicomponent quantum mechanical calculation with polarizable continuum model for proton chemical shift.

    Science.gov (United States)

    Kanematsu, Yusuke; Tachikawa, Masanori

    2015-05-21

    Multicomponent quantum mechanical (MC_QM) calculations with polarizable continuum model (PCM) have been tested against liquid (1)H NMR chemical shifts for a test set of 80 molecules. Improvement from conventional quantum mechanical calculations was achieved for MC_QM calculations. The advantage of the multicomponent scheme could be attributed to the geometrical change from the equilibrium geometry by the incorporation of the hydrogen nuclear quantum effect, while that of PCM can be attributed to the change of the electronic structure according to the polarization by solvent effects.

  18. Measurements of total OH reactivity during PROPHET-AMOS 2016

    Science.gov (United States)

    Rickly, P.; Sakowski, J.; Bottorff, B.; Lew, M.; Stevens, P. S.; Sklaveniti, S.; Locoge, N.; Dusanter, S.

    2017-12-01

    As one of the main oxidant in the atmosphere, the hydroxyl radical (OH) initiates the oxidation of volatile organic compounds that can lead to the formation of ozone and secondary organic aerosols. Understanding both the sources and sinks of OH is therefore important to address issues related to air quality and climate change. Measurements of total OH reactivity can provide an important test of our understanding of the OH radical budget. Recent measurements of total reactivity in many environments have been greater than calculated based on the measured concentration of VOCs, suggesting that important OH sinks in these environments are not well characterized. Measurements of total OH reactivity were performed in a forested environment during the PROPHET - AMOS field campaign (Program for Research on Oxidants: PHotochemisty, Emissions, and Transport - Atmospheric Measurements of Oxidants in Summer) using the Comparative Reactivity Method (CRM) and the Total OH Loss Rate Method (TOHLM). The site is characterized by large emissions of isoprene and monoterpenes and low anthropogenic influence. Measurements of total OH reactivity using these two techniques agree to within their respective uncertainties, giving confidence in the measured OH reactivity. In addition, measurements of trace gases (VOCs, NOx, O3) were used to perform a comprehensive apportionment of OH sinks. These measurements are used in a chemical model using the Master Chemical Mechanism to calculate the expected OH reactivity. The results will be compared to previous measurements of total OH reactivity at this site.

  19. Assessing Stress-Induced Sleep Reactivity in College Students: The European Portuguese Version of the Ford Insomnia Response to Stress Test (FIRST)

    OpenAIRE

    Marques, Daniel Ruivo; Allen Gomes, Ana; Drake, Christopher Lawrence; Roth, Thomas; de Azevedo, Maria Helena Pinto

    2016-01-01

    Over the past few years, the comprehensive models of insomnia have exhibited impressive developments. However, there is scarce knowledge on predisposing or vulnerability factors for insomnia. One of the most promising constructs to aid in filling this gap is stress-induced sleep reactivity assessed through self-report. Our aim was to study the psychometric properties of the European Portuguese version of the Ford Insomnia Response to Stress Test (FIRST).

  20. 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.

  1. 78 FR 27860 - Revocation of TSCA Section 4 Testing Requirements for One High Production Volume Chemical Substance

    Science.gov (United States)

    2013-05-13

    ... unit for this chemical substance are no longer supported. III. Amendment to Chemical Testing... proposed rule document (Ref. 4). The EDF comment indicated support for the May 14, 2012 Federal Register.... Fresh Water Algal Growth Inhibition Test with C.I. Pigment Blue 61 study. Submitted on April 13, 2012...

  2. 77 FR 21065 - Certain High Production Volume Chemicals; Test Rule and Significant New Use Rule; Fourth Group of...

    Science.gov (United States)

    2012-04-09

    ... 2070-AJ66 Certain High Production Volume Chemicals; Test Rule and Significant New Use Rule; Fourth... an opportunity to comment on a proposed test rule for 23 high production volume (HPV) chemical... necessary, to prohibit or limit that activity before it occurs. The opportunity to present oral comment was...

  3. Evaluation of precipitates used in strainer head loss testing. Part I. Chemically generated precipitates

    International Nuclear Information System (INIS)

    Bahn, Chi Bum; Kasza, Ken E.; Shack, William J.; Natesan, Ken; Klein, Paul

    2009-01-01

    The purpose of the current program was to evaluate the properties of chemical precipitates proposed by industry that have been used in sump strainer head loss testing. Specific precipitates that were evaluated included aluminum oxyhydroxide (AlOOH) and sodium aluminum silicate (SAS) prepared according to the procedures in WCAP-16530-NP, along with precipitates formed from injecting chemicals into the test loop according to the procedure used by one sump strainer test vendor for U.S. pressurized water reactors. The settling rates of the surrogate precipitates are strongly dependent on their particle size and are reasonably consistent with those expected from Stokes' Law or colloid aggregation models. Head loss tests showed that AlOOH and SAS surrogates are quite effective in increasing the head loss across a perforated pump inlet strainer that has an accumulated fibrous debris bed. The characteristics of aluminum hydroxide precipitate using sodium aluminate were dependent on whether it was formed in high-purity or ordinary tap water and whether excess silicate was present or not.

  4. Correlation of Chemical and Physical Test Data For the Environment Ageing of Coflon (PVDF). Revised

    Science.gov (United States)

    Morgan, G. J.; Campion, R. P.

    1997-01-01

    This report aims to identify correlations between mechanical property changes and chemical/morphological structure changes for Coflon. It is intended both to illustrate the overall methodology and to indicate the testing that needs to be undertaken in order to obtain correlations. Many fluid exposures have now been carried out on Coflon during the project and many data generated as a result. The report summarises the changes observed in mechanical and physical properties and relates these as well as possible to the chemistry thought to be occurring during ageing. For this purpose, data have been collated from already-issued MERL and TRI technical and progress reports. Most of the mechanical testing of aged testpieces has been performed soon after the completion of the exposure; however, there is of necessity a delay in obtaining chemical analysis of the same testpieces, so that more physical than chemical data are shown. Three fluids have so far caused measurable deterioration of Coflon, these being: methanol (Fluid A), a methanol and amine mixture (Fluid G), and a mixture of methane, carbon dioxide gas and hydrogen sulphide gas plus aqueous amine (Fluid F). Only the effects of these fluids will be dealt with in any detail in this report, although other fluids are assessed to give relevant background information. Relevant test data collated here include: tensile modulus and related properties, mode of sample failure at break, fracture toughness, fatigue crack growth rate and resistance, stress relaxation rate, permeation coefficients, % crystallinity and molecular weight distributions together with changes in fluorine levels, and other observations where appropriate. However, not all of these were obtained for every ageing condition. Because of the wide range of tests employed, and the different ways in which their results are obtained, the following section has been included to serve as a background for making comparisons.

  5. Hydrologic testing in wells near the Idaho Chemical Processing Plant at the Idaho National Engineering Laboratory

    International Nuclear Information System (INIS)

    Johnson, G.S.; Olsen, J.H.; Ralston, D.R.

    1994-01-01

    The Snake River Plain aquifer beneath the INEL is often viewed as a 2-dimensional system, but may actually possess 3-dimensional properties of concern. A straddle-packer system is being used by the State's INEL Oversight Program to isolate specific aquifer intervals and define the 3-dimensional chemical and hydrologic characteristics of the aquifer. The hydrologic test results from wells USGS 44, 45, and 46 near the Idaho Chemical Processing Plant indicate that: (1) Vertical variation in static head is less than 0.3 feed, (2) barometric efficiencies are between 25 and 55 percent, and (3) the system responds to distant pumping as a multi-layered, but interconnected system. 3 refs., 7 figs., 3 tabs

  6. Chemical-Cleaning Demonstration Test No. 2 in a mock-up steam generator

    International Nuclear Information System (INIS)

    Jevec, J.M.; Leedy, W.S.

    1983-04-01

    This report describes the results of the mockup demonstration test of the first modified baseline process under Contract S-127, Chemical Cleaning of Nuclear Steam Generators. The objective of this program is to determine the feasibility of cleaning the secondary side of nuclear steam generators with state-of-the-art chemical cleaning technology. The first step was to benchmark a baseline process. This process was then modified to attempt to eliminate the causes of unacceptable cleaning performance. The modified baseline process consists of an EDTA/H 2 O 2 -based copper solvent and a near-neutral, EDTA/N 2 H 4 -based magnetite and crevice solvent. This report also presents the results of three inhibitor evaluation mockup runs used in the evaluation of the modified baseline process

  7. 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...

  8. Standard test methods for chemical, mass spectrometric, spectrochemical, nuclear, and radiochemical analysis of uranium hexafluoride

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2011-01-01

    1.1 These test methods cover procedures for subsampling and for chemical, mass spectrometric, spectrochemical, nuclear, and radiochemical analysis of uranium hexafluoride UF6. Most of these test methods are in routine use to determine conformance to UF6 specifications in the Enrichment and Conversion Facilities. 1.2 The analytical procedures in this document appear in the following order: Note 1—Subcommittee C26.05 will confer with C26.02 concerning the renumbered section in Test Methods C761 to determine how concerns with renumbering these sections, as analytical methods are replaced with stand-alone analytical methods, are best addressed in subsequent publications. Sections Subsampling of Uranium Hexafluoride 7 - 10 Gravimetric Determination of Uranium 11 - 19 Titrimetric Determination of Uranium 20 Preparation of High-Purity U3O 8 21 Isotopic Analysis 22 Isotopic Analysis by Double-Standard Mass-Spectrometer Method 23 - 29 Determination of Hydrocarbons, Chlorocarbons, and Partially Substitut...

  9. Accelerated detection of brown-rot decay : comparison of soil block test, chemical analysis, mechanical properties, and immunodetection

    Science.gov (United States)

    C. A. Clausen; S. N. Kartal

    2003-01-01

    Early detection of wood decay is critical because decay fungi can cause rapid structural failure. The objective of this study was to compare the sensitivity of different methods purported to detect brown-rot decay in the early stages of development. The immunodiagnostic wood decay (IWD)test, soil block test/cake pan test, mechanical property tests, and chemical...

  10. Efficacy studies of Reactive Skin Decontamination Lotion, M291 Skin Decontamination Kit, 0.5% bleach, 1% soapy water, and Skin Exposure Reduction Paste Against Chemical Warfare Agents, part 2: guinea pigs challenged with soman.

    Science.gov (United States)

    Braue, Ernest H; Smith, Kelly H; Doxzon, Bryce F; Lumpkin, Horace L; Clarkson, Edward D

    2011-03-01

    This report, the second in a series of five, directly compares the efficacy of Reactive Skin Decontamination Lotion (RSDL), the M291 Skin Decontamination Kit (SDK), 0.5% bleach (sodium or calcium hypochlorite solution), 1% soapy water, and Skin Exposure Reduction Paste Against Chemical Warfare Agents (SERPACWA) in the haired guinea pig model following exposure to soman (GD). In all experiments, guinea pigs were close-clipped and given anesthesia. In the decontamination experiments, the animals were challenged with GD and decontaminated after a 2-minute delay for the standard procedure or at longer times for the delayed-decontamination experiments. Positive control animals were challenged with GD in the same manner as the treated animals, except that they received no treatment. All animals were observed during the first 4 hours and again at 24 hours after exposure for signs of toxicity and death. The protective ratio (PR, defined as the median lethal dose [LD(50)] of the treatment group divided by the LD(50) of the untreated positive control animals) was calculated from the derived probit dose-response curves established for each treatment group and nontreated control animals. SERPACWA was applied as a thin coating (0.1 mm thick), allowed to dry for 15 minutes, and challenged with GD. After a 2-hour challenge, any remaining GD was blotted off the animal, but no additional decontamination was done. Significance in this report is defined as p decontamination experiments, the calculated PRs for RSDL, 0.5% bleach, 1% soapy water, and M291 SDK were 14, 2.7, 2.2, and 2.6, respectively. RSDL was by far the most effective decontamination product tested and significantly better than any of the other products. Bleach, soapy water, and the M291 SDK provided equivalent and modest protection. Since only RSDL provided at least good protection (PR > 5), it was the only decontamination product evaluated for delayed decontamination. In the GD delayed-decontamination experiments

  11. Influence of cytochrome 2C19 allelic variants on on-treatment platelet reactivity evaluated by five different platelet function tests.

    Science.gov (United States)

    Gremmel, Thomas; Kopp, Christoph W; Moertl, Deddo; Seidinger, Daniela; Koppensteiner, Renate; Panzer, Simon; Mannhalter, Christine; Steiner, Sabine

    2012-05-01

    The antiplatelet effect of clopidogrel has been linked to cytochrome P450 2C19 (CYP2C19) carrier status. The presence of loss of function and gain of function variants were found to have a gene-dose effect on clopidogrel metabolism. However, genotyping is only one aspect of predicting response to clopidogrel and several platelet function tests are available to measure platelet response. Patients and methods We studied the influence of CYP2C19 allelic variants on on-treatment platelet reactivity as assessed by light transmission aggregometry (LTA), the VerifyNow P2Y12 assay, the VASP assay, multiple electrode aggregometry (MEA), and the Impact-R in 288 patients after stenting for cardiovascular disease. Allelic variants of CYP2C19 were determined with the Infiniti® CYP450 2C19+ assay and categorized into four metabolizer states (ultrarapid, extensive, intermediate, poor). Platelet reactivity increased linearly from ultrarapid to poor metabolizers using the VerifyNow P2Y12 assay (P = 0.04), the VASP assay (P = 0.02) and the Impact-R (P = 0.04). The proportion of patients with high on-treatment residual platelet reactivity (HRPR) identified by LTA, the VerifyNow P2Y12 assay and the VASP assay increased when the metabolizer status decreased, while no such relationship could be identified for results of MEA and Impact-R. The presence of loss of function variants (*2/*2, *2-8*/wt, *2/*17) was an independent predictor of HRPR in LTA and the VASP assay while it did not reach statistical significance in the VerifyNow P2Y12 assay, MEA, and the Impact-R. Depending on the type of platelet function test differences in the association of on-treatment platelet reactivity with CYP2C19 carrier status are observed. Copyright © 2011 Elsevier Ltd. All rights reserved.

  12. Novel Semi-Direct OH Reactivity (kOH) Measurements by Chemical Ionization Mass Spectrometry during a Chamber Instrument Comparison Campaign and Continuous Ambient Air Sampling at a Central European GAW Station

    Science.gov (United States)

    Muller, J.; Kubistin, D.; Elste, T.; Plass-Duelmer, C.; Claude, A.; Englert, J.; Holla, R.; Fuchs, H.; Hofzumahaus, A.; Holland, F.; Novelli, A.; Tillmann, R.; Wegener, R.; Rohrer, F.; Yu, Z.; Bohn, B.; Williams, J.; Pfannerstill, E.; Edtbauer, A.; Kluepfel, T.

    2016-12-01

    Total OH reactivity (kOH) has been recognized as a useful measure to gauge the potential atmospheric oxidation capacity and a few different in-situ measurement techniques have been developed over the last 15 years. Here results are presented from a novel semi-direct method developed by the German Weather Service (DWD) utilizing a chemical ionization mass spectrometer (CIMS). Recently in April 2016, the CIMS system participated in a half-blind kOH instrument comparison campaign at the Forschungszentrum Jülich (FZJ) SAPHIR chamber. Experiments provided controlled conditions with a range of different VOC mixtures and varying NOx levels, representing environments dominated by biogenic or urban emissions. Alongside CIMS, kOH was also measured by systems using the comparative reactivity method (CRM) and the pump-probe technique with OH detection. The intercomparison revealed a good performance of CIMS at lower OH reactivities (0-15 s-1), a range for which the instrumental set up was optimized. Limitations of the CIMS system consist of an upper limit for kOH detection and the need for applying a chemical correction function as a result of instrument-internal HOx recycling. Findings and instrument parameters obtained from the FZJ SAPHIR campaign and flow tube experiments are then applied to ambient air kOH measurements at the Meteorological Observatory Hohenpeissenberg (MOHp), Germany. The CIMS instrument is used there for long-term measurements of OH, H2SO4, ROx and kOH. Here, we show ambient air kOH measurements, interpreted in conjunction with volatile organic compounds (VOC) and inorganic trace gases also measured at the GAW station Hohenpeissenberg. These observations provide a unique dataset to investigate turnover rates and seasonal cycles of reactive trace gases, i.e. sources that make up total OH reactivity in this central European, rural setting.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2012-07-01

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

  14. Spontaneous stabilization of HTGRs without reactor scram and core cooling—Safety demonstration tests using the HTTR: Loss of reactivity control and core cooling

    Energy Technology Data Exchange (ETDEWEB)

    Takamatsu, Kuniyoshi, E-mail: takamatsu.kuniyoshi@jaea.go.jp; Yan, Xing L.; Nakagawa, Shigeaki; Sakaba, Nariaki; Kunitomi, Kazuhiko

    2014-05-01

    It is well known that a High-Temperature Gas-cooled Reactor (HTGR) has superior safety characteristics; for example, an HTGR has a self-control system that uses only physical phenomena against various accidents. Moreover, the large heat capacity and low power density of the core result in very slow temperature transients. Therefore, an HTGR serves inherently safety features against loss of core cooling accidents such as the Tokyo Electric Power Co., Inc. (TEPCO)’s Fukushima Daiichi Nuclear Power Station (NPS) disaster. Herein we would like to demonstrate the inherent safety features using the High-Temperature Engineering Test Reactor (HTTR). The HTTR is the first HTGR in Japan with a thermal power of 30 MW and a maximum reactor outlet coolant temperature of 950 °C; it was built at the Oarai Research and Development Center of Japan Atomic Energy Agency (JAEA). In this study, an all-gas-circulator trip test was analyzed as a loss of forced cooling (LOFC) test with an initial reactor power of 9 MW to demonstrate LOFC accidents. The analytical results indicate that reactor power decreases from 9 MW to 0 MW owing to the negative reactivity feedback effect of the core, even if the reactor shutdown system is not activated. The total reactivity decreases for 2–3 h and then gradually increases in proportion to xenon reactivity; therefore, the HTTR achieves recritical after an elapsed time of 6–7 h, which is different from the elapsed time at reactor power peak occurrence. After the reactor power peak occurs, the total reactivity oscillates several times because of the negative reactivity feedback effect and gradually decreases to zero. Moreover, the new conclusions are as follows: the greater the amount of residual heat removed from the reactor core, the larger the stable reactor power after recriticality owing to the heat balance of the reactor system. The minimum reactor power and the reactor power peak occurrence are affected by the neutron source. The greater the

  15. Cardiovascular and cortisol reactivity and habituation to a virtual reality version of the Trier Social Stress Test: a pilot study

    DEFF Research Database (Denmark)

    Jönsson, Peter; Wallergård, Mattias; Osterberg, Kai

    2010-01-01

    reactivity and habituation to repeated stress provocations using a virtual reality (VR) version of TSST. The VR system was a CAVE™ system with three rear projected walls (4 m×3 m), and one floor projection. The system also included a head tracking system and passive stereoscopy. The virtual audience...... studies using the real-life TSST. If these results can be replicated with larger samples, VR technology may be used as a simple and standardized tool for social stress induction in experimental settings....