Computer program to solve two-dimensional shock-wave interference problems with an equilibrium chemically reacting air model

Science.gov (United States)

Glass, Christopher E.

1990-08-01

The computer program EASI, an acronym for Equilibrium Air Shock Interference, was developed to calculate the inviscid flowfield, the maximum surface pressure, and the maximum heat flux produced by six shock wave interference patterns on a 2-D, cylindrical configuration. Thermodynamic properties of the inviscid flowfield are determined using either an 11-specie, 7-reaction equilibrium chemically reacting air model or a calorically perfect air model. The inviscid flowfield is solved using the integral form of the conservation equations. Surface heating calculations at the impingement point for the equilibrium chemically reacting air model use variable transport properties and specific heat. However, for the calorically perfect air model, heating rate calculations use a constant Prandtl number. Sample calculations of the six shock wave interference patterns, a listing of the computer program, and flowcharts of the programming logic are included.

Extension of a semi-implicit shock-capturing algorithm for 3-D fully coupled, chemically reacting flows in generalized coordinates

International Nuclear Information System (INIS)

Shinn, J.L.; Yee, H.C.; Uenishi, K.; NASA, Ames Research Center, Moffett Field, CA; Vigyan Research Associates, Inc., Hampton, VA)

1987-01-01

A semiimplicit high-resolution shock-capturing method for multidimensional systems of hyperbolic conservation laws with stiff source terms has been developed by Yee and Shinn (1987). The goal of this work is to extend this method to solve the three-dimensional fully coupled Navier-Stokes equations for a hypersonic chemically reacting flow in generalized coordinates. In this formulation, the global continuity equation was replaced by all the species continuity equations. The shock-capturing technique is a second-order-accurate, symmetric total-variation-diminishing method which accounts fully and directly for the coupling among the fluid and all the species. To verify the current approach, it was implemented into an existing computer code which contained the MacCormack method. Test results for a five-species reacting flow are shown to be oscillation-free around the shock, and the time spent per iteration only doubles when compared to the result using classical way of supplying numerical dissipation. The extra computation is more than justified by the elimination of spurious oscillation and nonlinear instability associated with the classical shock-capturing schemes in computing hypersonic reacting flows. 27 references

Comparison of Mixing Calculations for Reacting and Non-Reacting Flows in a Cylindrical Duct

Science.gov (United States)

Oechsle, V. L.; Mongia, H. C.; Holdeman, J. D.

1994-01-01

A production 3-D elliptic flow code has been used to calculate non-reacting and reacting flow fields in an experimental mixing section relevant to a rich burn/quick mix/lean burn (RQL) combustion system. A number of test cases have been run to assess the effects of the variation in the number of orifices, mass flow ratio, and rich-zone equivalence ratio on the flow field and mixing rates. The calculated normalized temperature profiles for the non-reacting flow field agree qualitatively well with the normalized conserved variable isopleths for the reacting flow field indicating that non-reacting mixing experiments are appropriate for screening and ranking potential rapid mixing concepts. For a given set of jet momentum-flux ratio, mass flow ratio, and density ratio (J, MR, and DR), the reacting flow calculations show a reduced level of mixing compared to the non-reacting cases. In addition, the rich-zone equivalence ratio has noticeable effect on the mixing flow characteristics for reacting flows.

Applied patent RFID systems for building reacting HEPA air ventilation system in hospital operation rooms.

Science.gov (United States)

Lin, Jesun; Pai, Jar-Yuan; Chen, Chih-Cheng

2012-12-01

RFID technology, an automatic identification and data capture technology to provide identification, tracing, security and so on, was widely applied to healthcare industry in these years. Employing HEPA ventilation system in hospital is a way to ensure healthful indoor air quality to protect patients and healthcare workers against hospital-acquired infections. However, the system consumes lots of electricity which cost a lot. This study aims to apply the RFID technology to offer a unique medical staff and patient identification, and reacting HEPA air ventilation system in order to reduce the cost, save energy and prevent the prevalence of hospital-acquired infection. The system, reacting HEPA air ventilation system, contains RFID tags (for medical staffs and patients), sensor, and reacting system which receives the information regarding the number of medical staff and the status of the surgery, and controls the air volume of the HEPA air ventilation system accordingly. A pilot program was carried out in a unit of operation rooms of a medical center with 1,500 beds located in central Taiwan from Jan to Aug 2010. The results found the air ventilation system was able to function much more efficiently with less energy consumed. Furthermore, the indoor air quality could still keep qualified and hospital-acquired infection or other occupational diseases could be prevented.

Combined LAURA-UPS solution procedure for chemically-reacting flows. M.S. Thesis

Science.gov (United States)

Wood, William A.

1994-01-01

A new procedure seeks to combine the thin-layer Navier-Stokes solver LAURA with the parabolized Navier-Stokes solver UPS for the aerothermodynamic solution of chemically-reacting air flowfields. The interface protocol is presented and the method is applied to two slender, blunted shapes. Both axisymmetric and three dimensional solutions are included with surface pressure and heat transfer comparisons between the present method and previously published results. The case of Mach 25 flow over an axisymmetric six degree sphere-cone with a noncatalytic wall is considered to 100 nose radii. A stability bound on the marching step size was observed with this case and is attributed to chemistry effects resulting from the noncatalytic wall boundary condition. A second case with Mach 28 flow over a sphere-cone-cylinder-flare configuration is computed at both two and five degree angles of attack with a fully-catalytic wall. Surface pressures are seen to be within five percent with the present method compared to the baseline LAURA solution and heat transfers are within 10 percent. The effect of grid resolution is investigated and the nonequilibrium results are compared with a perfect gas solution, showing that while the surface pressure is relatively unchanged by the inclusion of reacting chemistry the nonequilibrium heating is 25 percent higher. The procedure demonstrates significant, order of magnitude reductions in solution time and required memory for the three dimensional case over an all thin-layer Navier-Stokes solution.

Thermodynamic Analysis of Chemically Reacting Mixtures-Comparison of First and Second Order Models.

Science.gov (United States)

Pekař, Miloslav

2018-01-01

Recently, a method based on non-equilibrium continuum thermodynamics which derives thermodynamically consistent reaction rate models together with thermodynamic constraints on their parameters was analyzed using a triangular reaction scheme. The scheme was kinetically of the first order. Here, the analysis is further developed for several first and second order schemes to gain a deeper insight into the thermodynamic consistency of rate equations and relationships between chemical thermodynamic and kinetics. It is shown that the thermodynamic constraints on the so-called proper rate coefficient are usually simple sign restrictions consistent with the supposed reaction directions. Constraints on the so-called coupling rate coefficients are more complex and weaker. This means more freedom in kinetic coupling between reaction steps in a scheme, i.e., in the kinetic effects of other reactions on the rate of some reaction in a reacting system. When compared with traditional mass-action rate equations, the method allows a reduction in the number of traditional rate constants to be evaluated from data, i.e., a reduction in the dimensionality of the parameter estimation problem. This is due to identifying relationships between mass-action rate constants (relationships which also include thermodynamic equilibrium constants) which have so far been unknown.

REACT-Mod: a mathematical model for transient calculation of chemical reactions with U-Pu-Np-Tc in the aqueous nitric acid solution

International Nuclear Information System (INIS)

Tachimori, Shoichi; Kitamura, Tatsuaki.

1996-10-01

A computer code REACT-Mod which simulates various chemical reactions in an aqueous nitric acid solution involving uranium, plutonium, neptunium, technetium etc. e.g., redox, radiolytic and disproportionation reactions of 68, was developed based on the kinetics model. The numerical solution method adopted in the code are two, a kinetics model totally based on the rate law of which differential equations are solved by the modified Porsing method, and a two-step model based on both the rate law and equilibrium law. Only the former treats 27 radiolytic reactions. The latter is beneficially used to have a quick and approximate result by economical computation. The present report aims not only to explain the concept, chemical reactions treated and characteristics of the model but also to provide details of the program for users of the REACT-Mod code. (author)

Recent advances in ultrafast-laser-based spectroscopy and imaging for reacting plasmas and flames

Science.gov (United States)

Patnaik, Anil K.; Adamovich, Igor; Gord, James R.; Roy, Sukesh

2017-10-01

Reacting flows and plasmas are prevalent in a wide array of systems involving defense, commercial, space, energy, medical, and consumer products. Understanding the complex physical and chemical processes involving reacting flows and plasmas requires measurements of key parameters, such as temperature, pressure, electric field, velocity, and number densities of chemical species. Time-resolved measurements of key chemical species and temperature are required to determine kinetics related to the chemical reactions and transient phenomena. Laser-based, noninvasive linear and nonlinear spectroscopic approaches have proved to be very valuable in providing key insights into the physico-chemical processes governing reacting flows and plasmas as well as validating numerical models. The advent of kilohertz rate amplified femtosecond lasers has expanded the multidimensional imaging of key atomic species such as H, O, and N in a significant way, providing unprecedented insight into preferential diffusion and production of these species under chemical reactions or electric-field driven processes. These lasers not only provide 2D imaging of chemical species but have the ability to perform measurements free of various interferences. Moreover, these lasers allow 1D and 2D temperature-field measurements, which were quite unimaginable only a few years ago. The rapid growth of the ultrafast-laser-based spectroscopic measurements has been fueled by the need to achieve the following when measurements are performed in reacting flows and plasmas. They are: (1) interference-free measurements (collision broadening, photolytic dissociation, Stark broadening, etc), (2) time-resolved single-shot measurements at a rate of 1-10 kHz, (3) spatially-resolved measurements, (4) higher dimensionality (line, planar, or volumetric), and (5) simultaneous detection of multiple species. The overarching goal of this article is to review the current state-of-the-art ultrafast-laser-based spectroscopic

Transport-induced shifts in condensate dew-point and composition in multicomponent systems with chemical reaction

Science.gov (United States)

Rosner, D. E.; Nagarajan, R.

1985-01-01

Partial heterogeneous condensation phenomena in multicomponent reacting systems are analyzed taking into consideration the chemical element transport phenomena. It is demonstrated that the dew-point surface temperature in chemically reactive systems is not a purely thermodynamic quantity, but is influenced by the multicomponent diffusion and Soret-mass diffusion phenomena. Several distinct dew-points are shown to exist in such systems and, as a result of transport constraints, the 'sharp' locus between two chemically distinct condensates is systematically moved to a difference mainstream composition.

Chemical reactions in reverse micelle systems

Science.gov (United States)

Matson, Dean W.; Fulton, John L.; Smith, Richard D.; Consani, Keith A.

1993-08-24

This invention is directed to conducting chemical reactions in reverse micelle or microemulsion systems comprising a substantially discontinuous phase including a polar fluid, typically an aqueous fluid, and a microemulsion promoter, typically a surfactant, for facilitating the formation of reverse micelles in the system. The system further includes a substantially continuous phase including a non-polar or low-polarity fluid material which is a gas under standard temperature and pressure and has a critical density, and which is generally a water-insoluble fluid in a near critical or supercritical state. Thus, the microemulsion system is maintained at a pressure and temperature such that the density of the non-polar or low-polarity fluid exceeds the critical density thereof. The method of carrying out chemical reactions generally comprises forming a first reverse micelle system including an aqueous fluid including reverse micelles in a water-insoluble fluid in the supercritical state. Then, a first reactant is introduced into the first reverse micelle system, and a chemical reaction is carried out with the first reactant to form a reaction product. In general, the first reactant can be incorporated into, and the product formed in, the reverse micelles. A second reactant can also be incorporated in the first reverse micelle system which is capable of reacting with the first reactant to form a product.

Reaction Ensemble Molecular Dynamics: Direct Simulation of the Dynamic Equilibrium Properties of Chemically Reacting Mixtures

Czech Academy of Sciences Publication Activity Database

Brennan, J.K.; Lísal, Martin; Gubbins, K.E.; Rice, B.M.

2004-01-01

Roč. 70, č. 6 (2004), 0611031-0611034 ISSN 1063-651X R&D Projects: GA ČR GA203/03/1588 Grant - others:NSF(US) CTS-0211792 Institutional research plan: CEZ:AV0Z4072921 Keywords : reacting systems * simulation * molecular dynamics Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.352, year: 2004

A framework for the design of reacting systems with phase transfer catalysis

DEFF Research Database (Denmark)

Piccolo, Chiara; Shaw, Andrew; Hodges, George

2012-01-01

A generic modelling framework for phase transition catalyst based reacting systems has been developed and converted into a software tool. The modelling framework accommodates models of different types representing different sub-systems of the PTCbased reactive system; databases of model parameters...... and carefully collected and checked (for thermodynamic consistency) experimentally measured data. The models, data and software have been tested on various PTC-based reactive systems. Illustrative examples are provided....

Chemical modeling of irreversible reactions in nuclear waste-water-rock systems

International Nuclear Information System (INIS)

Wolery, T.J.

1981-02-01

Chemical models of aqueous geochemical systems are usually built on the concept of thermodynamic equilibrium. Though many elementary reactions in a geochemical system may be close to equilibrium, others may not be. Chemical models of aqueous fluids should take into account that many aqueous redox reactions are among the latter. The behavior of redox reactions may critically affect migration of certain radionuclides, especially the actinides. In addition, the progress of reaction in geochemical systems requires thermodynamic driving forces associated with elementary reactions not at equilibrium, which are termed irreversible reactions. Both static chemical models of fluids and dynamic models of reacting systems have been applied to a wide spectrum of problems in water-rock interactions. Potential applications in nuclear waste disposal range from problems in geochemical aspects of site evaluation to those of waste-water-rock interactions. However, much further work in the laboratory and the field will be required to develop and verify such applications of chemical modeling

Fungal decay resistance of wood reacted with phosphorus pentoxide-amine system

Science.gov (United States)

Hong-Lin Lee; George C. Chen; Roger M. Rowell

2004-01-01

Resistance of wood reacted in situ with phosphorus pentoxide-amine to the brown-rot fungus Gloeophyllum trabeum and white-rot fungus Trametes versicolor was examined. Wood reacted with either octyl, tribromo, or nitro derivatives were more resistant to both fungi. Threshold retention values of phosphoramide-reacted wood to white-rot fungus T. versicolor ranged from 2.9...

Thermal properties of wood reacted with a phosphorus pentoxide–amine system

Science.gov (United States)

Hong-Lin Lee; George C. Chen; Roger M. Rowell

2004-01-01

The objective of this research was to improve the fire-retardant properties of wood in one treatment using a phosphorus pentoxide–amine system. Phosphorus pentoxide and 16 amines including alkyl, halophenyl, and phenyl amines were compounded in N,N-dimethylformamide and the resulting solutions containing phosphoramides were reacted with wood. The characteristics of...

The REACT Project

DEFF Research Database (Denmark)

Bloch, Paul; Blystad, Astrid; Byskov, Jens

decisions; and the provision of leadership and the enforcement of conditions. REACT - "REsponse to ACcountable priority setting for Trust in health systems" is an EU-funded five-year intervention study, which started in 2006 testing the application and effects of the AFR approach in one district each...... selected disease and programme interventions and services, within general care and on health systems management. Efforts to improve health sector performance have not yet been satisfactory, and adequate and sustainable improvements in health outcomes have not been shown. Priority setting in health systems...... improvements to health systems performance discussed....

Steam bubble growth in the bulk of overheated N2O4-NO chemically reacting solution

International Nuclear Information System (INIS)

Nemtsev, V.A.; Cherkashin, A.M.

1989-01-01

A mathematical model and numerical investigation of the vapour bubble growth that begins from the bubble critical size at the positive radius fluctuation during the initial moment in the bulk of the overheated N 2 O 4 -NO liquid solution are presented. The mathematical model has been stated under the following assumptions: the movement of a bubble wall and surrounding liquid is spherically symmetrical; thermal parameters in the bubble are distributed uniformly; the vapour phase follows the ideal gas law; heat transfer is not affected by the compressibility of liquid; if dissolution of light components is determined by Henry's law, then Hertz-Knudsen's equation determines the velocity of phase transition for a N 2 O 4 component. The mathematical model presented can be applied to another fluids, including chemically reacting ones

Multiphase reacting flows modelling and simulation

CERN Document Server

Marchisio, Daniele L

2007-01-01

The papers in this book describe the most widely applicable modeling approaches and are organized in six groups covering from fundamentals to relevant applications. In the first part, some fundamentals of multiphase turbulent reacting flows are covered. In particular the introduction focuses on basic notions of turbulence theory in single-phase and multi-phase systems as well as on the interaction between turbulence and chemistry. In the second part, models for the physical and chemical processes involved are discussed. Among other things, particular emphasis is given to turbulence modeling strategies for multiphase flows based on the kinetic theory for granular flows. Next, the different numerical methods based on Lagrangian and/or Eulerian schemes are presented. In particular the most popular numerical approaches of computational fluid dynamics codes are described (i.e., Direct Numerical Simulation, Large Eddy Simulation, and Reynolds-Averaged Navier-Stokes approach). The book will cover particle-based meth...

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

KAUST Repository

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

2014-01-01

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

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

KAUST Repository

Kedia, Kushal S.

2014-09-01

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

Propel: A Discontinuous-Galerkin Finite Element Code for Solving the Reacting Navier-Stokes Equations

Science.gov (United States)

Johnson, Ryan; Kercher, Andrew; Schwer, Douglas; Corrigan, Andrew; Kailasanath, Kazhikathra

2017-11-01

This presentation focuses on the development of a Discontinuous Galerkin (DG) method for application to chemically reacting flows. The in-house code, called Propel, was developed by the Laboratory of Computational Physics and Fluid Dynamics at the Naval Research Laboratory. It was designed specifically for developing advanced multi-dimensional algorithms to run efficiently on new and innovative architectures such as GPUs. For these results, Propel solves for convection and diffusion simultaneously with detailed transport and thermodynamics. Chemistry is currently solved in a time-split approach using Strang-splitting with finite element DG time integration of chemical source terms. Results presented here show canonical unsteady reacting flow cases, such as co-flow and splitter plate, and we report performance for higher order DG on CPU and GPUs.

Direct numerical simulations of reacting flows with detailed chemistry using many-core/GPU acceleration

KAUST Repository

Herná ndez Pé rez, Francisco E.; Mukhadiyev, Nurzhan; Xu, Xiao; Sow, Aliou; Lee, Bok Jik; Sankaran, Ramanan; Im, Hong G.

2018-01-01

A new direct numerical simulation (DNS) code for multi-component gaseous reacting flows has been developed at KAUST, with the state-of-the-art programming model for next generation high performance computing platforms. The code, named KAUST Adaptive Reacting Flows Solver (KARFS), employs the MPI+X programming, and relies on Kokkos for “X” for performance portability to multi-core, many-core and GPUs, providing innovative software development while maintaining backward compatibility with established parallel models and legacy code. The capability and potential of KARFS to perform DNS of reacting flows with large, detailed reaction mechanisms is demonstrated with various model problems involving ignition and turbulent flame propagations with varying degrees of chemical complexities.

Direct numerical simulations of reacting flows with detailed chemistry using many-core/GPU acceleration

KAUST Repository

Hernández Pérez, Francisco E.

2018-03-29

A new direct numerical simulation (DNS) code for multi-component gaseous reacting flows has been developed at KAUST, with the state-of-the-art programming model for next generation high performance computing platforms. The code, named KAUST Adaptive Reacting Flows Solver (KARFS), employs the MPI+X programming, and relies on Kokkos for “X” for performance portability to multi-core, many-core and GPUs, providing innovative software development while maintaining backward compatibility with established parallel models and legacy code. The capability and potential of KARFS to perform DNS of reacting flows with large, detailed reaction mechanisms is demonstrated with various model problems involving ignition and turbulent flame propagations with varying degrees of chemical complexities.

CFD analysis of hypersonic, chemically reacting flow fields

Science.gov (United States)

Edwards, T. A.

1993-01-01

Design studies are underway for a variety of hypersonic flight vehicles. The National Aero-Space Plane will provide a reusable, single-stage-to-orbit capability for routine access to low earth orbit. Flight-capable satellites will dip into the atmosphere to maneuver to new orbits, while planetary probes will decelerate at their destination by atmospheric aerobraking. To supplement limited experimental capabilities in the hypersonic regime, computational fluid dynamics (CFD) is being used to analyze the flow about these configurations. The governing equations include fluid dynamic as well as chemical species equations, which are being solved with new, robust numerical algorithms. Examples of CFD applications to hypersonic vehicles suggest an important role this technology will play in the development of future aerospace systems. The computational resources needed to obtain solutions are large, but solution adaptive grids, convergence acceleration, and parallel processing may make run times manageable.

Approximate solution to the Kolmogorov equation for a fission chain-reacting system

International Nuclear Information System (INIS)

Ruby, L.; McSwine, T.L.

1986-01-01

An approximate solution has been obtained for the Kolmogorov equation describing a fission chain-reacting system. The method considers the population of neutrons, delayed-neutron precursors, and detector counts. The effect of the detector is separated from the statistics of the chain reaction by a weak coupling assumption that predicts that the detector responds to the average rather than to the instantaneous neutron population. An approximate solution to the remaining equation, involving the populations of neutrons and precursors, predicts a negative-binomial behaviour for the neutron probability distribution

Direct numerical simulation of turbulent reacting flows

Energy Technology Data Exchange (ETDEWEB)

Chen, J.H. [Sandia National Laboratories, Livermore, CA (United States)

1993-12-01

The development of turbulent combustion models that reflect some of the most important characteristics of turbulent reacting flows requires knowledge about the behavior of key quantities in well defined combustion regimes. In turbulent flames, the coupling between the turbulence and the chemistry is so strong in certain regimes that is is very difficult to isolate the role played by one individual phenomenon. Direct numerical simulation (DNS) is an extremely useful tool to study in detail the turbulence-chemistry interactions in certain well defined regimes. Globally, non-premixed flames are controlled by two limiting cases: the fast chemistry limit, where the turbulent fluctuations. In between these two limits, finite-rate chemical effects are important and the turbulence interacts strongly with the chemical processes. This regime is important because industrial burners operate in regimes in which, locally the flame undergoes extinction, or is at least in some nonequilibrium condition. Furthermore, these nonequilibrium conditions strongly influence the production of pollutants. To quantify the finite-rate chemistry effect, direct numerical simulations are performed to study the interaction between an initially laminar non-premixed flame and a three-dimensional field of homogeneous isotropic decaying turbulence. Emphasis is placed on the dynamics of extinction and on transient effects on the fine scale mixing process. Differential molecular diffusion among species is also examined with this approach, both for nonreacting and reacting situations. To address the problem of large-scale mixing and to examine the effects of mean shear, efforts are underway to perform large eddy simulations of round three-dimensional jets.

Chemical equilibrium. [maximizing entropy of gas system to derive relations between thermodynamic variables

Science.gov (United States)

1976-01-01

The entropy of a gas system with the number of particles subject to external control is maximized to derive relations between the thermodynamic variables that obtain at equilibrium. These relations are described in terms of the chemical potential, defined as equivalent partial derivatives of entropy, energy, enthalpy, free energy, or free enthalpy. At equilibrium, the change in total chemical potential must vanish. This fact is used to derive the equilibrium constants for chemical reactions in terms of the partition functions of the species involved in the reaction. Thus the equilibrium constants can be determined accurately, just as other thermodynamic properties, from a knowledge of the energy levels and degeneracies for the gas species involved. These equilibrium constants permit one to calculate the equilibrium concentrations or partial pressures of chemically reacting species that occur in gas mixtures at any given condition of pressure and temperature or volume and temperature.

A model for reaction rates in turbulent reacting flows

Science.gov (United States)

Chinitz, W.; Evans, J. S.

1984-01-01

To account for the turbulent temperature and species-concentration fluctuations, a model is presented on the effects of chemical reaction rates in computer analyses of turbulent reacting flows. The model results in two parameters which multiply the terms in the reaction-rate equations. For these two parameters, graphs are presented as functions of the mean values and intensity of the turbulent fluctuations of the temperature and species concentrations. These graphs will facilitate incorporation of the model into existing computer programs which describe turbulent reacting flows. When the model was used in a two-dimensional parabolic-flow computer code to predict the behavior of an experimental, supersonic hydrogen jet burning in air, some improvement in agreement with the experimental data was obtained in the far field in the region near the jet centerline. Recommendations are included for further improvement of the model and for additional comparisons with experimental data.

A computer model for one-dimensional mass and energy transport in and around chemically reacting particles, including complex gas-phase chemistry, multicomponent molecular diffusion, surface evaporation, and heterogeneous reaction

Science.gov (United States)

Cho, S. Y.; Yetter, R. A.; Dryer, F. L.

1992-01-01

Various chemically reacting flow problems highlighting chemical and physical fundamentals rather than flow geometry are presently investigated by means of a comprehensive mathematical model that incorporates multicomponent molecular diffusion, complex chemistry, and heterogeneous processes, in the interest of obtaining sensitivity-related information. The sensitivity equations were decoupled from those of the model, and then integrated one time-step behind the integration of the model equations, and analytical Jacobian matrices were applied to improve the accuracy of sensitivity coefficients that are calculated together with model solutions.

ENVIRONMENT: a computational platform to stochastically simulate reacting and self-reproducing lipid compartments

Science.gov (United States)

Mavelli, Fabio; Ruiz-Mirazo, Kepa

2010-09-01

'ENVIRONMENT' is a computational platform that has been developed in the last few years with the aim to simulate stochastically the dynamics and stability of chemically reacting protocellular systems. Here we present and describe some of its main features, showing how the stochastic kinetics approach can be applied to study the time evolution of reaction networks in heterogeneous conditions, particularly when supramolecular lipid structures (micelles, vesicles, etc) coexist with aqueous domains. These conditions are of special relevance to understand the origins of cellular, self-reproducing compartments, in the context of prebiotic chemistry and evolution. We contrast our simulation results with real lab experiments, with the aim to bring together theoretical and experimental research on protocell and minimal artificial cell systems.

Sentinel Gap basalt reacted in a temperature gradient

International Nuclear Information System (INIS)

Charles, R.W.; Bayhurst, G.K.

1983-01-01

Six basalt prisms were reacted in a controlled temperature gradient hydrothermal circulation system for two months. The prisms were centered at 72, 119, 161, 209, 270, and 310 0 C. Total pressure was 1/3 kbar. All prisms showed large weight loss: 5.5% to 14.9%. The matrix micropegmatite and natural nontronitic alteration reacted readily to clays at all temperatures. The first four prisms were coated with a calcium smectite, and the last two prisms were covered with discrete patches of potassium-rich phengite and alkali feldspar. The results indicated that clays may act as adsorbers of various ions

Sentinel Gap basalt reacted in a temperature gradient

International Nuclear Information System (INIS)

Charles, R.W.; Bayhurst, G.K.

1982-01-01

Six basalt prisms were reacted in a controlled temperature gradient hydrothermal circulation system for two months. The prisms are centered at 72, 119, 161, 209, 270, and 310 0 C. Total pressure is 1/3 kbar. All prisms show large weight loss: 5.5% to 14.9%. The matrix micropegmatite and natural nontronitic alteration readily reacts to clays at all temperatures. The first four prisms are coated with a Ca-smectite while the last two prisms are covered with discrete patches of K rich phengite and alkali feldspar. The clays may act as adsorbers of various ions

Computation of turbulent reacting flow in a solid-propellant ducted rocket

Science.gov (United States)

Chao, Yei-Chin; Chou, Wen-Fuh; Liu, Sheng-Shyang

1995-05-01

A mathematical model for computation of turbulent reacting flows is developed under general curvilinear coordinate systems. An adaptive, streamline grid system is generated to deal with the complex flow structures in a multiple-inlet solid-propellant ducted rocket (SDR) combustor. General tensor representations of the k-epsilon and algebraic stress (ASM) turbulence models are derived in terms of contravariant velocity components, and modification caused by the effects of compressible turbulence is also included in the modeling. The clipped Gaussian probability density function is incorporated in the combustion model to account for fluctuations of properties. Validation of the above modeling is first examined by studying mixing and reacting characteristics in a confined coaxial-jet problem. This is followed by study of nonreacting and reacting SDR combustor flows. The results show that Gibson and Launder's ASM incorporated with Sarkar's modification for compressible turbulence effects based on the general curvilinear coordinate systems yields the most satisfactory prediction for this complicated SDR flowfield.

Study of transport and micro-structural properties of magnesium di-boride strand under react and bend mode and bend and react mode

International Nuclear Information System (INIS)

Kundu, Ananya; Das, Subrat Kumar; Bano, Anees; Pradhan, Subrata

2015-01-01

I-V characterization of commercial multi-filamentary Magnesium Di-Boride (MgB 2 ) wire of diameter 0.83 mm were studied in cryocooler based self-field characterization system under both react and bent mode and bent and react mode for a range of temperature 6 K - 25 K. This study is of practical technical relevance where the heat treatment of the superconducting wire makes the sample less flexible for winding in magnet and in other applications. There are limited reported data, available on degradation of MgB 2 wire with bending induced strain in react and wind and wind and react method. In the present work the bending diameter were varied from 80 mm to 20 mm in the interval of 10 mm change of bending diameter and for each case critical current (Ic) of the strand is measured for the above range of temperature. An ETP copper made customized sample holder for mounting the MgB 2 strand was fabricated and is thermally anchored to the cooling stage of the cryocooler. It is seen from the experimental data that in react and bent mode the critical current degrades from 105 A to 87 A corresponding to bending diameter of 80 mm and 20 mm respectively. The corresponding bending strain was analytically estimated and compared with the simulation result. It is also observed that in react and bent mode, the degradation of the transport property of the strand is less as compared to react and bent mode. For bent and react mode in the same sample, the critical current (Ic) was measured to be ∼145 A at 15 K for bending diameter of 20 mm. Apart from studying the bending induced strain on MgB 2 strand, the tensile test of the strand at RT was carried out. The electrical characterizations of the samples were accompanied by the microstructure analyses of the bent strand to examine the bending induced degradation in the grain structure of the strand. All these experimental findings are expected to be used as input to fabricate prototype MgB 2 based magnet. (author)

Combining discrete equations method and upwind downwind-controlled splitting for non-reacting and reacting two-fluid computations

International Nuclear Information System (INIS)

Tang, K.

2012-01-01

When numerically investigating multiphase phenomena during severe accidents in a reactor system, characteristic lengths of the multi-fluid zone (non-reactive and reactive) are found to be much smaller than the volume of the reactor containment, which makes the direct modeling of the configuration hardly achievable. Alternatively, we propose to consider the physical multiphase mixture zone as an infinitely thin interface. Then, the reactive Riemann solver is inserted into the Reactive Discrete Equations Method (RDEM) to compute high speed combustion waves represented by discontinuous interfaces. An anti-diffusive approach is also coupled with RDEM to accurately simulate reactive interfaces. Increased robustness and efficiency when computing both multiphase interfaces and reacting flows are achieved thanks to an original upwind downwind-controlled splitting method (UDCS). UDCS is capable of accurately solving interfaces on multi-dimensional unstructured meshes, including reacting fronts for both deflagration and detonation configurations. (author)

Lie Group Solution for Free Convective Flow of a Nanofluid Past a Chemically Reacting Horizontal Plate in a Porous Media

Directory of Open Access Journals (Sweden)

M. M. Rashidi

2014-01-01

Full Text Available The optimal homotopy analysis method (OHAM is employed to investigate the steady laminar incompressible free convective flow of a nanofluid past a chemically reacting upward facing horizontal plate in a porous medium taking into account heat generation/absorption and the thermal slip boundary condition. Using similarity transformations developed by Lie group analysis, the continuity, momentum, energy, and nanoparticle volume fraction equations are transformed into a set of coupled similarity equations. The OHAM solutions are obtained and verified by numerical results using a Runge-Kutta-Fehlberg fourth-fifth order method. The effect of the emerging flow controlling parameters on the dimensionless velocity, temperature, and nanoparticle volume fraction have been presented graphically and discussed. Good agreement is found between analytical and numerical results of the present paper with published results. This close agreement supports our analysis and the accuracy of the numerical computations. This paper also includes a representative set of numerical results for reduced Nusselt and Sherwood numbers in a table for various values of the parameters. It is concluded that the reduced Nusselt number increases with the Lewis number and reaction parameter whist it decreases with the order of the chemical reaction, thermal slip, and generation parameters.

Measurements of non-reacting and reacting flow fields of a liquid swirl flame burner

Science.gov (United States)

Chong, Cheng Tung; Hochgreb, Simone

2015-03-01

The understanding of the liquid fuel spray and flow field characteristics inside a combustor is crucial for designing a fuel efficient and low emission device. Characterisation of the flow field of a model gas turbine liquid swirl burner is performed by using a 2-D particle imaging velocimetry(PIV) system. The flow field pattern of an axial flow burner with a fixed swirl intensity is compared under confined and unconfined conditions, i.e., with and without the combustor wall. The effect of temperature on the main swirling air flow is investigated under open and non-reacting conditions. The result shows that axial and radial velocities increase as a result of decreased flow density and increased flow volume. The flow field of the main swirling flow with liquid fuel spray injection is compared to non-spray swirling flow. Introduction of liquid fuel spray changes the swirl air flow field at the burner outlet, where the radial velocity components increase for both open and confined environment. Under reacting condition, the enclosure generates a corner recirculation zone that intensifies the strength of radial velocity. The reverse flow and corner recirculation zone assists in stabilizing the flame by preheating the reactants. The flow field data can be used as validation target for swirl combustion modelling.

Stochastic models for turbulent reacting flows

Energy Technology Data Exchange (ETDEWEB)

Kerstein, A. [Sandia National Laboratories, Livermore, CA (United States)

1993-12-01

The goal of this program is to develop and apply stochastic models of various processes occurring within turbulent reacting flows in order to identify the fundamental mechanisms governing these flows, to support experimental studies of these flows, and to further the development of comprehensive turbulent reacting flow models.

TPR system: a powerful technique to monitor carbon nanotube formation during chemical vapour deposition

International Nuclear Information System (INIS)

Tristao, Juliana Cristina; Moura, Flavia Cristina Camilo; Lago, Rochel Montero; Sapag, Karim

2010-01-01

In this work, a TPR (Temperature Programmed Reduction) system is used as a powerful tool to monitor carbon nanotubes production during CVD (Chemical Vapour Deposition), The experiments were carried out using catalyst precursors based on Fe-Mo supported on Al 2 O 3 and methane as carbon source. As methane reacts on the Fe metal surface, carbon is deposited and H2 is produced. TPR is very sensitive to the presence of H2 and affords information on the temperature where catalyst is active to form different forms of carbon, the reaction kinetics, the catalyst deactivation and carbon yields. (author)

Modeling of turbulent chemical reaction

Science.gov (United States)

Chen, J.-Y.

1995-01-01

Viewgraphs are presented on modeling turbulent reacting flows, regimes of turbulent combustion, regimes of premixed and regimes of non-premixed turbulent combustion, chemical closure models, flamelet model, conditional moment closure (CMC), NO(x) emissions from turbulent H2 jet flames, probability density function (PDF), departures from chemical equilibrium, mixing models for PDF methods, comparison of predicted and measured H2O mass fractions in turbulent nonpremixed jet flames, experimental evidence of preferential diffusion in turbulent jet flames, and computation of turbulent reacting flows.

Mechanism for Self-Reacted Friction Stir Welding

Science.gov (United States)

Venable, Richard; Bucher, Joseph

2004-01-01

A mechanism has been designed to apply the loads (the stirring and the resection forces and torques) in self-reacted friction stir welding. This mechanism differs somewhat from mechanisms used in conventional friction stir welding, as described below. The tooling needed to apply the large reaction loads in conventional friction stir welding can be complex. Self-reacted friction stir welding has become popular in the solid-state welding community as a means of reducing the complexity of tooling and to reduce costs. The main problems inherent in self-reacted friction stir welding originate in the high stresses encountered by the pin-and-shoulder assembly that produces the weld. The design of the present mechanism solves the problems. The mechanism includes a redesigned pin-and-shoulder assembly. The welding torque is transmitted into the welding pin by a square pin that fits into a square bushing with set-screws. The opposite or back shoulder is held in place by a Woodruff key and high-strength nut on a threaded shaft. The Woodruff key reacts the torque, while the nut reacts the tensile load on the shaft.

Study of Transport and Micro-structural properties of Magnesium Di-Boride Strand under react and bend mode and bend and react mode

International Nuclear Information System (INIS)

Kundu, Ananya; Kumar Das, Subrat; Bano, Anees; Pradhan, Subrata

2017-01-01

I-V characterization of commercial multi-filamentary Magnesium Di-Boride (MgB 2 ) wire of diameter 0.83 mm were studied in Cryocooler at self-field I-V characterization system under both react and bend mode and bend and react mode for a range of temperature 6 K - 25 K. This study is of practical technical relevance where the heat treatment of the superconducting wire makes the wire less flexible for winding in magnet and in other applications. In the present work the bending diameter was varied from 40 mm to 20 mm and for each case critical current (I c ) of the strand is measured for above range of temperature. A customized sample holder is fabricated and thermally anchored with the 2 nd cold stage of Cryocooler. It is observed from the measurement that the strand is more susceptible to degradation for react and bend cases. The transport measurement of the strand was accompanied by SEM analyses of bend samples. Also the tensile strength of the raw strands and the heat treated strands were carried out at room temperature in Universal Testing Machine (UTM) to have an estimate about the limiting winding tension value during magnet fabrication. (paper)

Chemical changes in the chloroform-paraffin system irradiated by 60Co gamma-rays, 1

International Nuclear Information System (INIS)

Yoshino, Tomio; Sakaue, Muneko; Shimizu, Yasuko; Kawamura, Fumio.

1979-01-01

It has been reported that the chloroform-paraffin-dye system have excellent sensitivity for radiation as a solid chemical dosimeter or a phantom. However, the chemical changes in the irradiated system are not examined in detail. In the present study, the effect of paraffin on changes in the above system of a liquid state irradiated by 60 Co γ-rays was examined by using various normal paraffin, and the other variable factors on the changes were done. When the chloroform solution and the solution containing 25 per cent of paraffin by volume with 5.0 x 15 -5 mol/liter of Methyl Yellow as a dye were irradiated by 2000 R, G values for the formation of hydrogen chloride in the both solutions were 8.4 and 10.8, respectively, and were little affected by the kind of those, from C 6 (hexane) to C 36 (hexatria-contane). These results suggest that chlorine radical formed by radiolysis of chloroform may react with hydrogen atom from paraffin, thereby increasing the amount of hydrogen chloride. Presence of oxygen increased G value of the chloroform solution from 7.6 to 8.4, but did little that of the solution containing paraffin. (author)

Some aspects of theory and mathematics of thermal runaway in reacting chemical systems that may be relevant to critical behaviour in confined plasmas

International Nuclear Information System (INIS)

Ball, R. The

1999-01-01

The concept of an endothermally stabilised chemical reactor as an enthalpy coupled thermokinetic system is introduced, and given precise mathematical expression in the form of a four-dimensional dynamical system. Criteria are defined for which the system is free of all kinds of thermal misbehaviour. This important dynamical result defines bounds for a large region of the parameter space within which the reactor may be operated safely. The formalism of singularity theory is extended to bifurcation surfaces in a studio of multiplicity and stability in the CSTR problem

Eco-friendly synthesis for MCM-41 nanoporous materials using the non-reacted reagents in mother liquor.

Science.gov (United States)

Ng, Eng-Poh; Goh, Jia-Yi; Ling, Tau Chuan; Mukti, Rino R

2013-03-04

Nanoporous materials such as Mobil composite material number 41 (MCM-41) are attractive for applications such as catalysis, adsorption, supports, and carriers. Green synthesis of MCM-41 is particularly appealing because the chemical reagents are useful and valuable. We report on the eco-friendly synthesis of MCM-41 nanoporous materials via multi-cycle approach by re-using the non-reacted reagents in supernatant as mother liquor after separating the solid product. This approach was achieved via minimal requirement of chemical compensation where additional fresh reactants were added into the mother liquor followed by pH adjustment after each cycle of synthesis. The solid product of each successive batch was collected and characterized while the non-reacted reagents in supernatant can be recovered and re-used to produce subsequent cycle of MCM-41. The multi-cycle synthesis is demonstrated up to three times in this research. This approach suggests a low cost and eco-friendly synthesis of nanoporous material since less waste is discarded after the product has been collected, and in addition, product yield can be maintained at the high level.

Chemical systems, chemical contiguity and the emergence of life

DEFF Research Database (Denmark)

Kee, Terrence P.; Monnard, Pierre Alain

2017-01-01

to complex chemical systems over specific isolated functional apparatuses. We will summarize the recent advances in system chemistry and show that chemical systems in the geochemical context imply a form of chemical contiguity in the syntheses of the various molecules that precede modern biomolecules....

Large-Eddy Simulations of Reacting Liquid Spray

Science.gov (United States)

Lederlin, Thomas; Sanjose, Marlene; Gicquel, Laurent; Cuenot, Benedicte; Pitsch, Heinz; Poinsot, Thierry

2008-11-01

Numerical simulation, which is commonly used in many stages of aero-engine design, still has to demonstrate its predictive capability for two-phase reacting flows. This study is a collaboration between Stanford University and CERFACS to perform LES of a realistic spray combustor installed at ONERA, Toulouse. The experimental configuration is computed on the same unstructured mesh with two different solvers: Stanford's CDP code and CERFACS's AVBP code. CDP uses a low-Mach, variable-density solver with implicit time advancement. Droplets are tracked in a Lagrangian point-particle framework. The combustion model uses a flamelet approach, based on two transported scalars, mixture fraction and reaction progress variable. AVBP is a fully compressible solver with explicit time advancement. The liquid phase is described with an Eulerian method. The flame-turbulence interaction is modeled using a dynamically-thickened flame. Results are compared with experimental data for three regimes: purely gaseous non-reacting flow, non-reacting flow with evaporating droplets, reacting flow with droplets. Both simulations show a good agreement with experimental data and also stress the difference and relative advantages of the numerical methods.

Chemical deposition methods using supercritical fluid solutions

Science.gov (United States)

Sievers, Robert E.; Hansen, Brian N.

1990-01-01

A method for depositing a film of a desired material on a substrate comprises dissolving at least one reagent in a supercritical fluid comprising at least one solvent. Either the reagent is capable of reacting with or is a precursor of a compound capable of reacting with the solvent to form the desired product, or at least one additional reagent is included in the supercritical solution and is capable of reacting with or is a precursor of a compound capable of reacting with the first reagent or with a compound derived from the first reagent to form the desired material. The supercritical solution is expanded to produce a vapor or aerosol and a chemical reaction is induced in the vapor or aerosol so that a film of the desired material resulting from the chemical reaction is deposited on the substrate surface. In an alternate embodiment, the supercritical solution containing at least one reagent is expanded to produce a vapor or aerosol which is then mixed with a gas containing at least one additional reagent. A chemical reaction is induced in the resulting mixture so that a film of the desired material is deposited.

Processes for converting biomass-derived feedstocks to chemicals and liquid fuels

Science.gov (United States)

Held, Andrew; Woods, Elizabeth; Cortright, Randy; Gray, Matthew

2018-04-17

The present invention provides processes, methods, and systems for converting biomass-derived feedstocks to liquid fuels and chemicals. The method generally includes the reaction of a hydrolysate from a biomass deconstruction process with hydrogen and a catalyst to produce a reaction product comprising one of more oxygenated compounds. The process also includes reacting the reaction product with a condensation catalyst to produce C.sub.4+ compounds useful as fuels and chemicals.

Processes for converting biomass-derived feedstocks to chemicals and liquid fuels

Science.gov (United States)

Held, Andrew; Woods, Elizabeth; Cortright, Randy; Gray, Matthew

2017-05-23

The present invention provides processes, methods, and systems for converting biomass-derived feedstocks to liquid fuels and chemicals. The method generally includes the reaction of a hydrolysate from a biomass deconstruction process with hydrogen and a catalyst to produce a reaction product comprising one of more oxygenated compounds. The process also includes reacting the reaction product with a condensation catalyst to produce C.sub.4+ compounds useful as fuels and chemicals.

On Medium Chemical Reaction in Diffusion-Based Molecular Communication: a Two-Way Relaying Example

OpenAIRE

Farahnak-Ghazani, Maryam; Aminian, Gholamali; Mirmohseni, Mahtab; Gohari, Amin; Nasiri-Kenari, Masoumeh

2016-01-01

Chemical reactions are a prominent feature of molecular communication (MC) systems, with no direct parallels in wireless communications. While chemical reactions may be used inside the transmitter nodes, receiver nodes or the communication medium, we focus on its utility in the medium in this paper. Such chemical reactions can be used to perform computation over the medium as molecules diffuse and react with each other (physical-layer computation). We propose the use of chemical reactions for...

Statistical analysis of the velocity and scalar fields in reacting turbulent wall-jets

Science.gov (United States)

Pouransari, Z.; Biferale, L.; Johansson, A. V.

2015-02-01

The concept of local isotropy in a chemically reacting turbulent wall-jet flow is addressed using direct numerical simulation (DNS) data. Different DNS databases with isothermal and exothermic reactions are examined. The chemical reaction and heat release effects on the turbulent velocity, passive scalar, and reactive species fields are studied using their probability density functions (PDFs) and higher order moments for velocities and scalar fields, as well as their gradients. With the aid of the anisotropy invariant maps for the Reynolds stress tensor, the heat release effects on the anisotropy level at different wall-normal locations are evaluated and found to be most accentuated in the near-wall region. It is observed that the small-scale anisotropies are persistent both in the near-wall region and inside the jet flame. Two exothermic cases with different Damköhler numbers are examined and the comparison revealed that the Damköhler number effects are most dominant in the near-wall region, where the wall cooling effects are influential. In addition, with the aid of PDFs conditioned on the mixture fraction, the significance of the reactive scalar characteristics in the reaction zone is illustrated. We argue that the combined effects of strong intermittency and strong persistency of anisotropy at the small scales in the entire domain can affect mixing and ultimately the combustion characteristics of the reacting flow.

Large eddy simulation and direct numerical simulation of high speed turbulent reacting flows

Science.gov (United States)

Adumitroaie, V.; Frankel, S. H.; Madnia, C. K.; Givi, P.

The objective of this research is to make use of Large Eddy Simulation (LES) and Direct Numerical Simulation (DNS) for the computational analyses of high speed reacting flows. Our efforts in the first phase of this research conducted within the past three years have been directed in several issues pertaining to intricate physics of turbulent reacting flows. In our previous 5 semi-annual reports submitted to NASA LaRC, as well as several technical papers in archival journals, the results of our investigations have been fully described. In this progress report which is different in format as compared to our previous documents, we focus only on the issue of LES. The reason for doing so is that LES is the primary issue of interest to our Technical Monitor and that our other findings were needed to support the activities conducted under this prime issue. The outcomes of our related investigations, nevertheless, are included in the appendices accompanying this report. The relevance of the materials in these appendices are, therefore, discussed only briefly within the body of the report. Here, results are presented of a priori and a posterior analyses for validity assessments of assumed Probability Density Function (PDF) methods as potential subgrid scale (SGS) closures for LES of turbulent reacting flows. Simple non-premixed reacting systems involving an isothermal reaction of the type A + B yields Products under both chemical equilibrium and non-equilibrium conditions are considered. A priori analyses are conducted of a homogeneous box flow, and a spatially developing planar mixing layer to investigate the performance of the Pearson Family of PDF's as SGS models. A posteriori analyses are conducted of the mixing layer using a hybrid one-equation Smagorinsky/PDF SGS closure. The Smagorinsky closure augmented by the solution of the subgrid turbulent kinetic energy (TKE) equation is employed to account for hydrodynamic fluctuations, and the PDF is employed for modeling the

Incorporation of a Chemical Equilibrium Equation of State into LOCI-Chem

Science.gov (United States)

Cox, Carey F.

2005-01-01

Renewed interest in development of advanced high-speed transport, reentry vehicles and propulsion systems has led to a resurgence of research into high speed aerodynamics. As this flow regime is typically dominated by hot reacting gaseous flow, efficient models for the characteristic chemical activity are necessary for accurate and cost effective analysis and design of aerodynamic vehicles that transit this regime. The LOCI-Chem code recently developed by Ed Luke at Mississippi State University for NASA/MSFC and used by NASA/MSFC and SSC represents an important step in providing an accurate, efficient computational tool for the simulation of reacting flows through the use of finite-rate kinetics [3]. Finite rate chemistry however, requires the solution of an additional N-1 species mass conservation equations with source terms involving reaction kinetics that are not fully understood. In the equilibrium limit, where the reaction rates approach infinity, these equations become very stiff. Through the use of the assumption of local chemical equilibrium the set of governing equations is reduced back to the usual gas dynamic equations, and thus requires less computation, while still allowing for the inclusion of reacting flow phenomenology. The incorporation of a chemical equilibrium equation of state module into the LOCI-Chem code was the primary objective of the current research. The major goals of the project were: (1) the development of a chemical equilibrium composition solver, and (2) the incorporation of chemical equilibrium solver into LOCI-Chem. Due to time and resource constraints, code optimization was not considered unless it was important to the proper functioning of the code.

Low Mach number asymptotics for reacting compressible fluid flows

Czech Academy of Sciences Publication Activity Database

Feireisl, Eduard; Petzeltová, Hana

2010-01-01

Roč. 26, č. 2 (2010), s. 455-480 ISSN 1078-0947 R&D Projects: GA ČR GA201/05/0164 Institutional research plan: CEZ:AV0Z10190503 Keywords : low Mach number * Navier-Stokes-Fourier system * reacting fluids Subject RIV: BA - General Mathematics Impact factor: 0.986, year: 2010 http://www.aimsciences.org/journals/displayArticles.jsp?paperID=4660

Quantitative imaging of turbulent and reacting flows

Energy Technology Data Exchange (ETDEWEB)

Paul, P.H. [Sandia National Laboratories, Livermore, CA (United States)

1993-12-01

Quantitative digital imaging, using planar laser light scattering techniques is being developed for the analysis of turbulent and reacting flows. Quantitative image data, implying both a direct relation to flowfield variables as well as sufficient signal and spatial dynamic range, can be readily processed to yield two-dimensional distributions of flowfield scalars and in turn two-dimensional images of gradients and turbulence scales. Much of the development of imaging techniques to date has concentrated on understanding the requisite molecular spectroscopy and collision dynamics to be able to determine how flowfield variable information is encoded into the measured signal. From this standpoint the image is seen as a collection of single point measurements. The present effort aims at realizing necessary improvements in signal and spatial dynamic range, signal-to-noise ratio and spatial resolution in the imaging system as well as developing excitation/detection strategies which provide for a quantitative measure of particular flowfield scalars. The standard camera used for the study is an intensified CCD array operated in a conventional video format. The design of the system was based on detailed modeling of signal and image transfer properties of fast UV imaging lenses, image intensifiers and CCD detector arrays. While this system is suitable for direct scalar imaging, derived quantities (e.g. temperature or velocity images) require an exceptionally wide dynamic range imaging detector. To apply these diagnostics to reacting flows also requires a very fast shuttered camera. The authors have developed and successfully tested a new type of gated low-light level detector. This system relies on fast switching of proximity focused image-diode which is direct fiber-optic coupled to a cooled CCD array. Tests on this new detector show significant improvements in detection limit, dynamic range and spatial resolution as compared to microchannel plate intensified arrays.

An implicit multigrid algorithm for computing hypersonic, chemically reacting viscous flows

International Nuclear Information System (INIS)

Edwards, J.R.

1996-01-01

An implicit algorithm for computing viscous flows in chemical nonequilibrium is presented. Emphasis is placed on the numerical efficiency of the time integration scheme, both in terms of periteration workload and overall convergence rate. In this context, several techniques are introduced, including a stable, O(m 2 ) approximate factorization of the chemical source Jacobian and implementations of V-cycle and filtered multigrid acceleration methods. A five species-seventeen reaction air model is used to calculate hypersonic viscous flow over a cylinder at conditions corresponding to flight at 5 km/s, 60 km altitude and at 11.36 km/s, 76.42 km altitude. Inviscid calculations using an eleven-species reaction mechanism including ionization are presented for a case involving 11.37 km/s flow at an altitude of 84.6 km. Comparisons among various options for the implicit treatment of the chemical source terms and among different multilevel approaches for convergence acceleration are presented for all simulations

Insulation and Heat Treatment of Bi-2212 Wire for Wind-and-React Coils

Energy Technology Data Exchange (ETDEWEB)

Peter K. F. Hwang

2007-10-22

Higher Field Magnets demand higher field materials such as Bi-2212 round superconducting wire. The Bi-2212 wire manufacture process depends on the coil fabrication method and wire insulation material. Considering the wind-and-react method, the coil must unifirmly heated to the melt temperature and uniformly cooled to the solidification temperature. During heat treat cycle for tightly wound coils, the leakage melt from conductor can chemically react with insulation on the conductor and creat short turns in the coils. In this research project, conductor, insulation, and coils are made to systemically study the suitable insulation materials, coil fabrication method, and heat treatment cycles. In this phase I study, 800 meters Bi-2212 wire with 3 different insulation materials have been produced. Best insulation material has been identified after testing six small coils for insulation integrity and critical current at 4.2 K. Four larger coils (2" dia) have been also made with Bi-2212 wrapped with best insulation and with different heattreatment cycle. These coils were tested for Ic in a 6T background field and at 4.2 K. The test result shows that Ic from 4 coils are very close to short samples (1 meter) result. It demonstrates that HTS coils can be made with Bi-2212 wire with best insulation consistently. Better wire insulation, improving coil winding technique, and wire manufacture process can be used for a wide range of high field magnet application including acclerators such as Muon Collider, fusion energy research, NMR spectroscopy, MRI, and other industrial magnets.

Insulation and Heat Treatment of Bi-2212 Wires for Wind-and-React Coils

International Nuclear Information System (INIS)

Hwang, Peter K.F.

2007-01-01

Higher Field Magnets demand higher field materials such as Bi-2212 round superconducting wire. The Bi-2212 wire manufacture process depends on the coil fabrication method and wire insulation material. Considering the wind-and-react method, the coil must unifirmly heated to the melt temperature and uniformly cooled to the solidification temperature. During heat treat cycle for tightly wound coils, the leakage melt from conductor can chemically react with insulation on the conductor and creat short turns in the coils. In this research project, conductor, insulation, and coils are made to systemically study the suitable insulation materials, coil fabrication method, and heat treatment cycles. In this phase I study, 800 meters Bi-2212 wire with 3 different insulation materials have been produced. Best insulation material has been identified after testing six small coils for insulation integrity and critical current at 4.2 K. Four larger coils (2-inch dia) have been also made with Bi-2212 wrapped with best insulation and with different heattreatment cycle. These coils were tested for Ic in a 6T background field and at 4.2 K. The test result shows that Ic from 4 coils are very close to short samples (1 meter) result. It demonstrates that HTS coils can be made with Bi-2212 wire with best insulation consistently. Better wire insulation, improving coil winding technique, and wire manufacture process can be used for a wide range of high field magnet application including acclerators such as Muon Collider, fusion energy research, NMR spectroscopy, MRI, and other industrial magnets.

Reacting plasma project at IPP Japan

International Nuclear Information System (INIS)

Miyahara, A.; Momota, H.; Hamada, Y.; Kawamura, K.; Akimune, H.

1981-01-01

Contributed papers of the seminar on burning plasma held at UCLA are collected. Paper on ''overview of reacting plasma project'' described aim and philosophy of R-Project in Japan. Paper on ''Burning plasma and requirements for design'' gave theoretical aspect of reacting plasma physics while paper on ''plasma container, heating and diagnostics'' treated experimental aspect. Tritium handling is essential for the next step experiment; therefore, paper on ''Tritium problems in burning plasma experiments'' took an important part of this seminar. As appendix, paper on ''a new type of D - ion source using Si-semiconductor'' was added because such an advanced R and D work is essential for R-Project. (author)

Efficient removal of sulfur hexafluoride (SF6) through reacting with recycled electroplating sludge.

Science.gov (United States)

Zhang, Jia; Zhou, Ji Zhi; Liu, Qiang; Qian, Guangren; Xu, Zhi Ping

2013-06-18

This paper reports that recycled electroplating sludge is able to efficiently remove greenhouse gas sulfur hexafluoride (SF6). The removal process involves various reactions of SF6 with the recycled sludge. Remarkably, the sludge completely removed SF6 at a capacity of 1.10 mmol/g (SF6/sludge) at 600 °C. More importantly, the evolved gases were SO2, SiF4, and a limited amount of HF, with no toxic SOF4, SO2F2, or SF4 being detected. These generated gases can be readily captured and removed by NaOH solution. The reacted solids were further found to be various metal fluorides, thus revealing that SF6 removal takes place by reacting with various metal oxides and silicate in the sludge. Moreover, the kinetic investigation revealed that the SF6 reaction with the sludge is a first-order chemically controlled process. This research thus demonstrates that the waste electroplating sludge can be potentially used as an effective removal agent for one of the notorious greenhouse gases, SF6.

System for chemical decontamination of nuclear reactor primary systems

International Nuclear Information System (INIS)

Schlonski, J.S.; McGiure, M.F.; Corpora, G.J.

1992-01-01

This patent describes a method of chemically decontaminating a nuclear reactor primary system, having a residual heat removal system with one or more residual heat removal heat exchangers, each having an upstream and a downstream side, at or above ambient pressure. It comprises: injecting decontamination chemicals using an injection means; circulating the injected decontamination chemicals throughout the primary system; directing the circulated decontamination chemicals and process fluids to a means for removing suspended solids and dissolved materials after the circulated chemicals and process fluids have passed through the residual heat removal heat exchanger; decontaminating the process fluids; and feeding the decontaminated process fluids to the injection means. This patent also describes a chemical decontamination system for use at, or above, ambient pressure in a nuclear reactor primary system having a residual heat removal system. It comprises: means for injecting decontamination chemicals into the primary system; means for removing dissolved and suspended materials and decontamination chemicals from the primary system; one or more residual heat removal pumps; means located downstream of one of the residual heat removal heat exchangers; and a return line connecting the means

Computational Systems Chemical Biology

OpenAIRE

Oprea, Tudor I.; May, Elebeoba E.; Leitão, Andrei; Tropsha, Alexander

2011-01-01

There is a critical need for improving the level of chemistry awareness in systems biology. The data and information related to modulation of genes and proteins by small molecules continue to accumulate at the same time as simulation tools in systems biology and whole body physiologically-based pharmacokinetics (PBPK) continue to evolve. We called this emerging area at the interface between chemical biology and systems biology systems chemical biology, SCB (Oprea et al., 2007).

Cross-reacting and heterospecific monoclonal antibodies produced against arabis mosaic nepovirus.

Science.gov (United States)

Frison, E A; Stace-Smith, R

1992-10-01

Monoclonal antibodies (MAbs) were produced against arabis mosaic nepovirus (AMV). A hybridoma screening procedure was applied which involved the testing of culture supernatants, before the hybridomas were cloned to single cell lines, for their reaction with eight nepoviruses [AMV, cherry leafroll virus (CLRV), grapevine fanleaf virus (GFLV), peach rosette mosaic virus, raspberry ringspot virus (RRSV), tobacco ringspot virus, tomato black ring virus (TBRV) and tomato ringspot virus]. In addition to AMV-specific MAbs, this screening technique has allowed the selection of two cross-reacting MAbs: one reacting with AMV and GFLV, and one reacting with AMV and RRSV. This is the first report of MAbs cross-reacting with these nepoviruses. In addition, five heterospecific MAbs (HS-MAbs) could be selected: two reacting with RRSV, two with CLRV and one with TBRV. The usefulness of the screening technique that was applied for the selection of cross-reacting MAbs and HS-MAbs, and the potential use of such antibodies are discussed.

Chemical digestion of low level nuclear solid waste material

International Nuclear Information System (INIS)

Cooley, C.R.; Lerch, R.E.

1976-01-01

A chemical digestion for treatment of low level combustible nuclear solid waste material is provided and comprises reacting the solid waste material with concentrated sulfuric acid at a temperature within the range of 230 0 --300 0 C and simultaneously and/or thereafter contacting the reacting mixture with concentrated nitric acid or nitrogen dioxide. In a special embodiment spent ion exchange resins are converted by this chemical digestion to noncombustible gases and a low volume noncombustible residue. 6 claims, no drawings

REAC/TS radiation accident registry. Update of accidents in the United States

International Nuclear Information System (INIS)

Ricks, R.C.; Berger, M.E.; Holloway, E.C.; Goans, R.E.

2000-01-01

Serious injury due to ionizing radiation is a rare occurrence. From 1944 to the present, 243 US accidents meeting dose criteria for classification as serious are documented in the REAC/TS Registry. Thirty individuals have lost their lives in radiation accidents in the United States. The Registry is part of the overall REAC/TS program providing 24-hour direct or consultative assistance regarding medical and heath physics problems associated with radiation accidents in local, national, and international incidents. The REAC/TS Registry serves as a repository of medically important information documenting the consequences of these accidents. Registry data are gathered from various sources. These include reports from the World Heath Organization (WHO), International Atomic Energy Agency (IAEA), US Nuclear Regulatory Commission (US NRC), state radiological health departments, medical/health physics literature, personal communication, the Internet, and most frequently, from calls for medical assistance to REAC/TS, as part of our 24-hour medical assistance program. The REAC/TS Registry for documentation of radiation accidents serves several useful purposes: 1) weaknesses in design, safety practices, training or control can be identified, and trends noted; 2) information regarding the medical consequences of injuries and the efficacy of treatment protocols is available to the treating physician; and 3) Registry case studies serve as valuable teaching tools. This presentation will review and summarize data on the US radiation accidents including their classification by device, accident circumstances, and frequency by respective states. Data regarding accidents with fatal outcomes will be reviewed. The inclusion of Registry data in the IAEA's International Reporting System of Radiation Events (RADEV) will also be discussed. (author)

On the deduction of chemical reaction pathways from measurements of time series of concentrations.

Science.gov (United States)

Samoilov, Michael; Arkin, Adam; Ross, John

2001-03-01

We discuss the deduction of reaction pathways in complex chemical systems from measurements of time series of chemical concentrations of reacting species. First we review a technique called correlation metric construction (CMC) and show the construction of a reaction pathway from measurements on a part of glycolysis. Then we present two new improved methods for the analysis of time series of concentrations, entropy metric construction (EMC), and entropy reduction method (ERM), and illustrate (EMC) with calculations on a model reaction system. (c) 2001 American Institute of Physics.

Development of a Reduced-Order Model for Reacting Gas-Solids Flow using Proper Orthogonal Decomposition

Energy Technology Data Exchange (ETDEWEB)

McDaniel, Dwayne [Florida International Univ., Miami, FL (United States); Dulikravich, George [Florida International Univ., Miami, FL (United States); Cizmas, Paul [Florida International Univ., Miami, FL (United States)

2017-11-27

This report summarizes the objectives, tasks and accomplishments made during the three year duration of this research project. The report presents the results obtained by applying advanced computational techniques to develop reduced-order models (ROMs) in the case of reacting multiphase flows based on high fidelity numerical simulation of gas-solids flow structures in risers and vertical columns obtained by the Multiphase Flow with Interphase eXchanges (MFIX) software. The research includes a numerical investigation of reacting and non-reacting gas-solids flow systems and computational analysis that will involve model development to accelerate the scale-up process for the design of fluidization systems by providing accurate solutions that match the full-scale models. The computational work contributes to the development of a methodology for obtaining ROMs that is applicable to the system of gas-solid flows. Finally, the validity of the developed ROMs is evaluated by comparing the results against those obtained using the MFIX code. Additionally, the robustness of existing POD-based ROMs for multiphase flows is improved by avoiding non-physical solutions of the gas void fraction and ensuring that the reduced kinetics models used for reactive flows in fluidized beds are thermodynamically consistent.

Criterion for selection of quasi-equilibrium and quasi-frozen flows of chemically reacting mixture N2O4 reversible 2NO2reversible 2NO+O2 with heat isobaric supply (removal)

International Nuclear Information System (INIS)

Kostik, G.Eh.; Shiryaeva, N.M.

1979-01-01

Is suggested the criterion of quasi-equilibrium and quasi-frozen flows with isobaric heat supply (removal), including the basic external factors, which affect on the kinetics of chemical process. This criterion is the complex [g/Fq], where g is the coolant rate, F is the channel cross-section, q is the heat flow. Estimated formulae for quasi-equilibrium [g/Fq]sub(e) and quasi-frozen [g/Fq]sub(f) flows are obtained. The states of deviation from equilibrium and frozen conditions in linear region are considered, are listed graphical dependences lg[g/Fq]sub(e), lg[g/Fq]sub(el), lg[g/Fq]sub(f), lg[g/Eq]sub(fl), as functions of equilibrium parameter Tsub(e), pressure and frozen coordinate of epsilonsub(2f) reaction. This graphs give the possibility to estimate rapidly and obviously the flow character of chemically reacting coolant

Chemical Kinetics of Progesterone Radioimmunoassay System

International Nuclear Information System (INIS)

Abdel-Fattah, A.A.; Moustsfs, K.A.; El-Kolally, M.T.

2004-01-01

Progesterone is one of the steroids secreted by the corpus Iuteum in females during the menstrual cycle, and in a much higher amount by the placenta during pregnancy. It is also secreted in a minor quantities by the adrenal cortex in both males and females. Measurement of serum progesterone represents one of diagnostic values in menstrual disorders and infertility. The progesterone radioimmunoassay is based on the competition between unlabelled progesterone and a fixed quantity of 125 I-labeled progesterone for a limited number of binding sites on progesterone specific antibody. Allowing for a fixed amount of magnetizable immunosorbent to react, the antigen-antibody complex is bound on solid particles which are then separated by magnetic rack, and the radioactivity of the solid phase was counted using gamma counter. In this work, the chemical kinetics of the assay was followed, where the specific rate constant (K) was calculated at 4 degree and 37 degree and the activation energy (E act ) were calculated and the reaction rate was deduced

Systems and methods for solar cells with CIS and CIGS films made by reacting evaporated copper chlorides with selenium

Science.gov (United States)

Albin, David S.; Noufi, Rommel

2015-06-09

Systems and methods for solar cells with CIS and CIGS films made by reacting evaporated copper chlorides with selenium are provided. In one embodiment, a method for fabricating a thin film device comprises: providing a semiconductor film comprising indium (In) and selenium (Se) upon a substrate; heating the substrate and the semiconductor film to a desired temperature; and performing a mass transport through vapor transport of a copper chloride vapor and se vapor to the semiconductor film within a reaction chamber.

Entropy Filtered Density Function for Large Eddy Simulation of Turbulent Reacting Flows

Science.gov (United States)

Safari, Mehdi

Analysis of local entropy generation is an effective means to optimize the performance of energy and combustion systems by minimizing the irreversibilities in transport processes. Large eddy simulation (LES) is employed to describe entropy transport and generation in turbulent reacting flows. The entropy transport equation in LES contains several unclosed terms. These are the subgrid scale (SGS) entropy flux and entropy generation caused by irreversible processes: heat conduction, mass diffusion, chemical reaction and viscous dissipation. The SGS effects are taken into account using a novel methodology based on the filtered density function (FDF). This methodology, entitled entropy FDF (En-FDF), is developed and utilized in the form of joint entropy-velocity-scalar-turbulent frequency FDF and the marginal scalar-entropy FDF, both of which contain the chemical reaction effects in a closed form. The former constitutes the most comprehensive form of the En-FDF and provides closure for all the unclosed filtered moments. This methodology is applied for LES of a turbulent shear layer involving transport of passive scalars. Predictions show favor- able agreements with the data generated by direct numerical simulation (DNS) of the same layer. The marginal En-FDF accounts for entropy generation effects as well as scalar and entropy statistics. This methodology is applied to a turbulent nonpremixed jet flame (Sandia Flame D) and predictions are validated against experimental data. In both flows, sources of irreversibility are predicted and analyzed.

Potential performance improvement using a reacting gas (nitrogin tetroxide) as the working fluid in a closed Brayton cycle

Science.gov (United States)

Stochl, R. J.

1979-01-01

The results of an analysis to estimate the performance that could be obtained by using a chemically reacting gas (nitrogen tetroxide) as the working fluid in a closed Brayton cycle are presented. Compared with data for helium as the working fluid, these results indicate efficiency improvements from 4 to 90 percent, depending on turbine inlet temperature, pressures, and gas residence time in heat transfer equipment.

Chemical stimulation techniques for geothermal wells: experiments on the three-well EGS system at Soultz-sous-Forêts, France

OpenAIRE

Portier, Sandrine; Vuataz, François-David; Nami, Patrick; Sanjuan, Bernard; Gérard, André

2012-01-01

Rock matrix stimulation is a method of enhancing well production or injection within a broad range of challenging environments, varying from naturally fractured limestones to sandstones with complex mineralogy. A common and often successful stimulation option, matrix acidizing, utilizes acids that react and remove mineral phases restricting fluid flow. Reviewed is the technology of chemical treatments available for oil, gas and geothermal wells and the key elements and results of the chemical...

A constitutive theory of reacting electrolyte mixtures

Science.gov (United States)

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

2013-11-01

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

Introduction to the Chemical Management System

International Nuclear Information System (INIS)

Sawyer, J.G.

1993-01-01

The CMS, a Laboratory-wide electronic chemical inventory tracking system, will assist PNL by establishing comprehensive, integrated, Laboratory-wide databases supported by consistent and standardized procedures for chemical inventory management. It will provide PNL with the information needed to meet its current chemical management responsibilities and regulatory requirements. Its objectives are to provide an inventory of all chemicals being held at PNL facilities, to provide a specific location for all chemical containers, to ensure that health and safety regulatory codes are being upheld, and to provide PNL staff and managers with hazardous-chemical information for better inventory management. It is composed of 5 modules: chemical purchasing; chemical inventory; chemical names, properties, and hazardous groups; reporting; and system manager

Hazardous chemical tracking system (HAZ-TRAC)

International Nuclear Information System (INIS)

Bramlette, J.D.; Ewart, S.M.; Jones, C.E.

1990-07-01

Westinghouse Idaho Nuclear Company, Inc. (WINCO) developed and implemented a computerized hazardous chemical tracking system, referred to as Haz-Trac, for use at the Idaho Chemical Processing Plant (ICPP). Haz-Trac is designed to provide a means to improve the accuracy and reliability of chemical information, which enhances the overall quality and safety of ICPP operations. The system tracks all chemicals and chemical components from the time they enter the ICPP until the chemical changes form, is used, or becomes a waste. The system runs on a Hewlett-Packard (HP) 3000 Series 70 computer. The system is written in COBOL and uses VIEW/3000, TurboIMAGE/DBMS 3000, OMNIDEX, and SPEEDWARE. The HP 3000 may be accessed throughout the ICPP, and from remote locations, using data communication lines. Haz-Trac went into production in October, 1989. Currently, over 1910 chemicals and chemical components are tracked on the system. More than 2500 personnel hours were saved during the first six months of operation. Cost savings have been realized by reducing the time needed to collect and compile reporting information, identifying and disposing of unneeded chemicals, and eliminating duplicate inventories. Haz-Trac maintains information required by the Superfund Amendment Reauthorization Act (SARA), the Comprehensive Environmental Response, Compensation and Liability Act (CERCLA) and the Occupational Safety and Health Administration (OSHA)

Hazardous chemical tracking system (HAZ-TRAC)

Energy Technology Data Exchange (ETDEWEB)

Bramlette, J D; Ewart, S M; Jones, C E

1990-07-01

Westinghouse Idaho Nuclear Company, Inc. (WINCO) developed and implemented a computerized hazardous chemical tracking system, referred to as Haz-Trac, for use at the Idaho Chemical Processing Plant (ICPP). Haz-Trac is designed to provide a means to improve the accuracy and reliability of chemical information, which enhances the overall quality and safety of ICPP operations. The system tracks all chemicals and chemical components from the time they enter the ICPP until the chemical changes form, is used, or becomes a waste. The system runs on a Hewlett-Packard (HP) 3000 Series 70 computer. The system is written in COBOL and uses VIEW/3000, TurboIMAGE/DBMS 3000, OMNIDEX, and SPEEDWARE. The HP 3000 may be accessed throughout the ICPP, and from remote locations, using data communication lines. Haz-Trac went into production in October, 1989. Currently, over 1910 chemicals and chemical components are tracked on the system. More than 2500 personnel hours were saved during the first six months of operation. Cost savings have been realized by reducing the time needed to collect and compile reporting information, identifying and disposing of unneeded chemicals, and eliminating duplicate inventories. Haz-Trac maintains information required by the Superfund Amendment Reauthorization Act (SARA), the Comprehensive Environmental Response, Compensation and Liability Act (CERCLA) and the Occupational Safety and Health Administration (OSHA).

Laminar or turbulent boundary-layer flows of perfect gases or reacting gas mixtures in chemical equilibrium

Science.gov (United States)

Anderson, E. C.; Lewis, C. H.

1971-01-01

Turbulent boundary layer flows of non-reacting gases are predicted for both interal (nozzle) and external flows. Effects of favorable pressure gradients on two eddy viscosity models were studied in rocket and hypervelocity wind tunnel flows. Nozzle flows of equilibrium air with stagnation temperatures up to 10,000 K were computed. Predictions of equilibrium nitrogen flows through hypervelocity nozzles were compared with experimental data. A slender spherically blunted cone was studied at 70,000 ft altitude and 19,000 ft/sec. in the earth's atmosphere. Comparisons with available experimental data showed good agreement. A computer program was developed and fully documented during this investigation for use by interested individuals.

Approximate method for stochastic chemical kinetics with two-time scales by chemical Langevin equations

International Nuclear Information System (INIS)

Wu, Fuke; Tian, Tianhai; Rawlings, James B.; Yin, George

2016-01-01

The frequently used reduction technique is based on the chemical master equation for stochastic chemical kinetics with two-time scales, which yields the modified stochastic simulation algorithm (SSA). For the chemical reaction processes involving a large number of molecular species and reactions, the collection of slow reactions may still include a large number of molecular species and reactions. Consequently, the SSA is still computationally expensive. Because the chemical Langevin equations (CLEs) can effectively work for a large number of molecular species and reactions, this paper develops a reduction method based on the CLE by the stochastic averaging principle developed in the work of Khasminskii and Yin [SIAM J. Appl. Math. 56, 1766–1793 (1996); ibid. 56, 1794–1819 (1996)] to average out the fast-reacting variables. This reduction method leads to a limit averaging system, which is an approximation of the slow reactions. Because in the stochastic chemical kinetics, the CLE is seen as the approximation of the SSA, the limit averaging system can be treated as the approximation of the slow reactions. As an application, we examine the reduction of computation complexity for the gene regulatory networks with two-time scales driven by intrinsic noise. For linear and nonlinear protein production functions, the simulations show that the sample average (expectation) of the limit averaging system is close to that of the slow-reaction process based on the SSA. It demonstrates that the limit averaging system is an efficient approximation of the slow-reaction process in the sense of the weak convergence.

Three-dimensional reacting shock–bubble interaction

NARCIS (Netherlands)

Diegelmann, Felix; Hickel, S.; Adams, Nikolaus A.

2017-01-01

We investigate a reacting shock–bubble interaction through three-dimensional numerical simulations with detailed chemistry. The convex shape of the bubble focuses the shock and generates regions of high pressure and temperature, which are sufficient to ignite the diluted stoichiometric

Methane reacts with heteropolyacids chemisorbed on silica to produce acetic acid under soft conditions

KAUST Repository

Sun, Miao

2013-01-16

Selective functionalization of methane at moderate temperature is of crucial economic, environmental, and scientific importance. Here, we report that methane reacts with heteropolyacids (HPAs) chemisorbed on silica to produce acetic acid under soft conditions. Specially, when chemisorbed on silica, H 4SiW12O40, H3PW12O 40, H4SiMo12O40, and H 3PMo12O40 activate the primary C-H bond of methane at room temperature and atmospheric pressure. With these systems, acetic acid is produced directly from methane, in a single step, in the absence of Pd and without adding CO. Extensive surface characterization by solid-state NMR spectroscopy, IR spectroscopy, cyclic voltammetry, and X-ray photoelectron spectroscopy suggests that C-H activation of methane is triggered by the protons in the HPA-silica interface with concerted reduction of the Keggin cage, leading to water formation and hydration of the interface. This is the simplest and mildest way reported to date to functionalize methane. © 2012 American Chemical Society.

Lean premixed reacting flows with swirl and wall-separation zones in a contracting chamber

Science.gov (United States)

Zhang, Yuxin; Rusak, Zvi; Wang, Shixiao

2017-11-01

Low Mach number lean premixed reacting swirling flows with wall-separation zones in a contracting circular finite-length open chamber are studied. Assuming a complete reaction with high activation energy and chemical equilibrium behind the reaction zone, a nonlinear partial differential equation is derived for the solution of the flow stream function behind the reaction zone in terms of the inlet total enthalpy for a reacting flow, specific entropy and the circulation functions. Bifurcation diagrams of steady flows are described as the inlet swirl level is increased at fixed chamber contraction and reaction heat release. The approach is applied to an inlet solid-body rotation flow with constant profiles of the axial velocity, temperature and mixture reactant mass fraction. The computed results provide predictions of the critical inlet swirl levels for the first appearance of wall-separation states and for the size of the separation zone as a function of the inlet swirl ratio, Mach number, chamber contraction and heat release of the reaction. The methodology developed in this paper provides a theoretical feasibility for the development of the technology of swirl-assisted combustion where the reaction zone is supported and stabilized by a wall-separation zone.

Characterization of forced response of density stratified reacting wake

Science.gov (United States)

Pawar, Samadhan A.; Sujith, Raman I.; Emerson, Benjamin; Lieuwen, Tim

2018-02-01

The hydrodynamic stability of a reacting wake depends primarily on the density ratio [i.e., ratio of unburnt gas density (ρu) to burnt gas density (ρb)] of the flow across the wake. The variation of the density ratio from high to low value, keeping ρ u / ρ b > 1 , transitions dynamical characteristics of the reacting wake from a linearly globally stable (or convectively unstable) to a globally unstable mode. In this paper, we propose a framework to analyze the effect of harmonic forcing on the deterministic and synchronization characteristics of reacting wakes. Using the recurrence quantification analysis of the forced wake response, we show that the deterministic behaviour of the reacting wake increases as the amplitude of forcing is increased. Furthermore, for different density ratios, we found that the synchronization of the top and bottom branches of the wake with the forcing signal is dependent on whether the mean frequency of the natural oscillations of the wake (fn) is lesser or greater than the frequency of external forcing (ff). We notice that the response of both branches (top and bottom) of the reacting wake to the external forcing is asymmetric and symmetric for the low and high density ratios, respectively. Furthermore, we characterize the phase-locking behaviour between the top and bottom branches of the wake for different values of density ratios. We observe that an increase in the density ratio results in a gradual decrease in the relative phase angle between the top and bottom branches of the wake, which leads to a change in the vortex shedding pattern from a sinuous (anti-phase) to a varicose (in-phase) mode of the oscillations.

Acoustic wave propagation in fluids with coupled chemical reactions

International Nuclear Information System (INIS)

Margulies, T.S.; Schwarz, W.H.

1984-08-01

This investigation presents a hydroacoustic theory which accounts for sound absorption and dispersion in a multicomponent mixture of reacting fluids (assuming a set of first-order acoustic equations without diffusion) such that several coupled reactions can occur simultaneously. General results are obtained in the form of a biquadratic characteristic equation (called the Kirchhoff-Langevin equation) for the complex propagation variable chi = - (α + iω/c) in which α is the attenuation coefficient, c is the phase speed of the progressive wave and ω is the angular frequency. Computer simulations of sound absorption spectra have been made for three different chemical systems, each comprised of two-step chemical reactions using physico-chemical data available in the literature. The chemical systems studied include: (1) water-dioxane, (2) aqueous solutions of glycine and (3) cobalt polyphosphate mixtures. Explicit comparisons are made between the exact biquadratic characteristic solution and the approximate equation (sometimes referred to as a Debye equation) previously applied to interpret the experimental data for the chemical reaction contribution to the absorption versus frequency. The relative chemical reaction and classical viscothermal contributions to the sound absorption are also presented. Several discrepancies that can arise when estimating thermodynamic data (chemical reaction heats or volume changes) for multistep chemical reaction systems when making dilute solution or constant density assumptions are discussed

Chemical systems, chemical contiguity and the emergence of life

Directory of Open Access Journals (Sweden)

Terrence P. Kee

2017-08-01

Full Text Available Charting the emergence of living cells from inanimate matter remains an intensely challenging scientific problem. The complexity of the biochemical machinery of cells with its exquisite intricacies hints at cells being the product of a long evolutionary process. Research on the emergence of life has long been focusing on specific, well-defined problems related to one aspect of cellular make-up, such as the formation of membranes or the build-up of information/catalytic apparatus. This approach is being gradually replaced by a more “systemic” approach that privileges processes inherent to complex chemical systems over specific isolated functional apparatuses. We will summarize the recent advances in system chemistry and show that chemical systems in the geochemical context imply a form of chemical contiguity in the syntheses of the various molecules that precede modern biomolecules.

Soil chemical sensor and precision agricultural chemical delivery system and method

Science.gov (United States)

Colburn, Jr., John W.

1991-01-01

A real time soil chemical sensor and precision agricultural chemical delivery system includes a plurality of ground-engaging tools in association with individual soil sensors which measure soil chemical levels. The system includes the addition of a solvent which rapidly saturates the soil/tool interface to form a conductive solution of chemicals leached from the soil. A multivalent electrode, positioned within a multivalent frame of the ground-engaging tool, applies a voltage or impresses a current between the electrode and the tool frame. A real-time soil chemical sensor and controller senses the electrochemical reaction resulting from the application of the voltage or current to the leachate, measures it by resistivity methods, and compares it against pre-set resistivity levels for substances leached by the solvent. Still greater precision is obtained by calibrating for the secondary current impressed through solvent-less soil. The appropriate concentration is then found and the servo-controlled delivery system applies the appropriate amount of fertilizer or agricultural chemicals substantially in the location from which the soil measurement was taken.

An experimental and numerical study of confined non-reacting and reacting turbulent jets to facilitate homogeneous combustion in industrial furnaces

Science.gov (United States)

Lee, Insu

Confined non-reacting turbulent jets are ideal for recirculating the hot flue gas back into the furnace from an external exhaust duct. Such jets are also used inside the furnace to internally entrain and recirculate the hot flue gas to preheat and dilute the reactants. Both internal and external implementation of confined turbulent jets increase the furnace thermal efficiency. For external implementation, depending on the circumstances, the exhaust gas flow may be co- or counter-flow relative to the jet flow. Inside the furnaces, fuel and air jets are injected separately. To create a condition which can facilitate near homogeneous combustion, these jets have to first mix with the burned gas inside the furnace and simultaneously being heated and diluted prior to combustion. Clearly, the combustion pattern and emissions from reacting confined turbulent jets are affected by jet interactions, mixing and entrainment of hot flue gas. In this work, the flow and mixing characteristics of a non-reacting and reacting confined turbulent jet are investigated experimentally and numerically. This work consists of two parts: (i) A study of flow and mixing characteristics of non-reacting confined turbulent jets with co- or counter-flowing exhaust/flue gas. Here the axial and radial distributions of temperature, velocity and NO concentration (used as a tracer gas) were measured. FLUENT was used to numerically simulate the experimental results. This work provides the basic understanding of the flow and mixing characteristics of confined turbulent jets and develops some design considerations for recirculating flue gas back into the furnace as expressed by the recirculation zone and the stagnation locations. (ii) Numerical calculations of near homogeneous combustion are performed for the existing furnace. The exact geometry of the furnace in the lab is used and the real dimensional boundary conditions are considered. The parameters such as air nozzle diameter (dair), fuel nozzle

Low temperature radio-chemical energy conversion processes

International Nuclear Information System (INIS)

Gomberg, H.J.

1986-01-01

This patent describes a radio-chemical method of converting radiated energy into chemical energy form comprising the steps of: (a) establishing a starting chemical compound in the liquid phase that chemically reacts endothermically to radiation and heat energy to produce a gaseous and a solid constituent of the compound, (b) irradiating the compound in its liquid phase free of solvents to chemically release therefrom in response to the radiation the gaseous and solid constituents, (c) physically separating the solid and gaseous phase constituents from the liquid, and (d) chemically processing the constituents to recover therefrom energy stored therein by the irradiation step (b)

Rock-fluid chemical interactions at reservoir conditions: The influence of brine chemistry and extent of reaction

Science.gov (United States)

Anabaraonye, B. U.; Crawshaw, J.; Trusler, J. P. M.

2016-12-01

Following carbon dioxide injection in deep saline aquifers, CO2 dissolves in the formation brines forming acidic solutions that can subsequently react with host reservoir minerals, altering both porosity and permeability. The direction and rates of these reactions are influenced by several factors including properties that are associated with the brine system. Consequently, understanding and quantifying the impacts of the chemical and physical properties of the reacting fluids on overall reaction kinetics is fundamental to predicting the fate of the injected CO2. In this work, we present a comprehensive experimental study of the kinetics of carbonate-mineral dissolution in different brine systems including sodium chloride, sodium sulphate and sodium bicarbonate of varying ionic strengths. The impacts of the brine chemistry on rock-fluid chemical reactions at different extent of reactions are also investigated. Using a rotating disk technique, we have investigated the chemical interactions between the CO2-saturated brines and carbonate minerals at conditions of pressure (up to 10 MPa) and temperature (up to 373 K) pertinent to carbon storage. The changes in surface textures due to dissolution reaction were studied by means of optical microscopy and vertical scanning interferometry. Experimental results are compared to previously derived models.

ReACT!: An Interactive Educational Tool for AI Planning for Robotics

Science.gov (United States)

Dogmus, Zeynep; Erdem, Esra; Patogulu, Volkan

2015-01-01

This paper presents ReAct!, an interactive educational tool for artificial intelligence (AI) planning for robotics. ReAct! enables students to describe robots' actions and change in dynamic domains without first having to know about the syntactic and semantic details of the underlying formalism, and to solve planning problems using…

MPSalsa a finite element computer program for reacting flow problems. Part 2 - user`s guide

Energy Technology Data Exchange (ETDEWEB)

Salinger, A.; Devine, K.; Hennigan, G.; Moffat, H. [and others

1996-09-01

This manual describes the use of MPSalsa, an unstructured finite element (FE) code for solving chemically reacting flow problems on massively parallel computers. MPSalsa has been written to enable the rigorous modeling of the complex geometry and physics found in engineering systems that exhibit coupled fluid flow, heat transfer, mass transfer, and detailed reactions. In addition, considerable effort has been made to ensure that the code makes efficient use of the computational resources of massively parallel (MP), distributed memory architectures in a way that is nearly transparent to the user. The result is the ability to simultaneously model both three-dimensional geometries and flow as well as detailed reaction chemistry in a timely manner on MT computers, an ability we believe to be unique. MPSalsa has been designed to allow the experienced researcher considerable flexibility in modeling a system. Any combination of the momentum equations, energy balance, and an arbitrary number of species mass balances can be solved. The physical and transport properties can be specified as constants, as functions, or taken from the Chemkin library and associated database. Any of the standard set of boundary conditions and source terms can be adapted by writing user functions, for which templates and examples exist.

Temporal Control over Transient Chemical Systems using Structurally Diverse Chemical Fuels.

Science.gov (United States)

Chen, Jack L-Y; Maiti, Subhabrata; Fortunati, Ilaria; Ferrante, Camilla; Prins, Leonard J

2017-08-25

The next generation of adaptive, intelligent chemical systems will rely on a continuous supply of energy to maintain the functional state. Such systems will require chemical methodology that provides precise control over the energy dissipation process, and thus, the lifetime of the transiently activated function. This manuscript reports on the use of structurally diverse chemical fuels to control the lifetime of two different systems under dissipative conditions: transient signal generation and the transient formation of self-assembled aggregates. The energy stored in the fuels is dissipated at different rates by an enzyme, which installs a dependence of the lifetime of the active system on the chemical structure of the fuel. In the case of transient signal generation, it is shown that different chemical fuels can be used to generate a vast range of signal profiles, allowing temporal control over two orders of magnitude. Regarding self-assembly under dissipative conditions, the ability to control the lifetime using different fuels turns out to be particularly important as stable aggregates are formed only at well-defined surfactant/fuel ratios, meaning that temporal control cannot be achieved by simply changing the fuel concentration. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Fabrication of chemically cross-linked porous gelatin matrices.

Science.gov (United States)

Bozzini, Sabrina; Petrini, Paola; Altomare, Lina; Tanzi, Maria Cristina

2009-01-01

The aim of this study was to chemically cross-link gelatin, by reacting its free amino groups with an aliphatic diisocyanate. To produce hydrogels with controllable properties, the number of reacting amino groups was carefully determined. Porosity was introduced into the gelatin-based hydrogels through the lyophilization process. Porous and non-porous matrices were characterized with respect to their chemical structure, morphology, water uptake and mechanical properties. The physical, chemical and mechanical properties of the porous matrices are related to the extent of their cross-linking, showing that they can be controlled by varying the reaction parameters. Water uptake values (24 hours) vary between 160% and 200% as the degree of cross-linking increases. The flexibility of the samples also decreases by changing the extent of cross-linking. Young's modulus shows values between 0.188 KPa, for the highest degree, and 0.142 KPa for the lowest degree. The matrices are potential candidates for use as tissue-engineering scaffolds by modulating their physical chemical properties according to the specific application.

Plasma-chemical processes and systems

International Nuclear Information System (INIS)

Castro B, J.

1987-01-01

The direct applications of plasma technology on chemistry and metallurgy are presented. The physical fundaments of chemically active non-equilibrium plasma, the reaction kinetics, and the physical chemical transformations occuring in the electrical discharges, which are applied in the industry, are analysed. Some plasma chemical systems and processes related to the energy of hydrogen, with the chemical technology and with the metallurgy are described. Emphasis is given to the optimization of the energy effectiveness of these processes to obtain reducers and artificial energetic carriers. (M.C.K.) [pt

Investigation of Na-CO2 Reaction with Initial Reaction in Various Reacting Surface

International Nuclear Information System (INIS)

Kim, Hyun Su; Park, Gunyeop; Kim, Soo Jae; Park, Hyun Sun; Kim, Moo Hwan; Wi, Myung-Hwan

2015-01-01

The reaction products that cause oxidation and erosion are threaten the heat transfer tubes so that it is necessary to investigate Na-CO 2 reaction according to various experimental parameter. Unlike SWR, Na-CO 2 reaction is more complex to deal with reaction kinetics. Since a comprehensive understanding of Na-CO 2 reaction mechanism is crucial for the safety analysis, the reaction phenomenon under the various conditions was investigated. The current issue is to make a database for developing computational code for CO 2 gas leak situation because it is experimentally difficult to analyze the actual accident situation. Most studies on Na-CO 2 interaction reports that chemical reaction is getting vigorous as temperature increased and reactivity is sensitive as temperature change between 400 .deg. C and 600 .deg. C. Therefore, temperature range is determined based on the operating condition (450 - 500 .deg. C) of KALIMER-600 employed as supercritical CO 2 brayton cycle energy conversion system for Na-CO 2 heat exchanger. And next parameter is sodium surface area which contact between sodium and CO 2 when CO 2 is injected into sodium pool in the accident situation. So, the fundamental surface reaction is experimentally studied in the range of 8 - 12cm 2 . Additionally, it has been reported in recent years that CO 2 Flow rate affects reactivity less significantly and CO 2 flow rate is assumed that 5 SLPM (standard liter per minute) is suitable as a basis for a small leakage. The finally selected control parameters is sodium temperature and reacting surface area with constant CO 2 flow rate. Na-CO 2 reaction test is performed for investigating risk of potential accident which contacts with liquid sodium and CO 2 . Amount of reaction is saturated as time passed because of kept a balance between production of solid phase reaction products and amount of diffusivity. These results contribute to make a database for the SFR safety analysis and additional experiments are needed

A proposed chemical mechanism for biological phosphate removal ...

African Journals Online (AJOL)

DRINIE

2003-04-02

Apr 2, 2003 ... Water Utilisation Division, Department of Chemical Engineering, University of ... wastewater reacts with orthophosphate under anaerobic conditions to make ... role of acetates and other short-chain carbon compounds in bio-.

Advanced chemical oxygen iodine lasers for novel beam generation

Science.gov (United States)

Wu, Kenan; Zhao, Tianliang; Huai, Ying; Jin, Yuqi

2018-03-01

Chemical oxygen iodine laser, or COIL, is an impressive type of chemical laser that emits high power beam with good atmospheric transmissivity. Chemical oxygen iodine lasers with continuous-wave plane wave output are well-developed and are widely adopted in directed energy systems in the past several decades. Approaches of generating novel output beam based on chemical oxygen iodine lasers are explored in the current study. Since sophisticated physical processes including supersonic flowing of gaseous active media, chemical reacting of various species, optical power amplification, as well as thermal deformation and vibration of mirrors take place in the operation of COIL, a multi-disciplinary model is developed for tracing the interacting mechanisms and evaluating the performance of the proposed laser architectures. Pulsed output mode with repetition rate as high as hundreds of kHz, pulsed output mode with low repetition rate and high pulse energy, as well as novel beam with vector or vortex feature can be obtained. The results suggest potential approaches for expanding the applicability of chemical oxygen iodine lasers.

Combustion driven NF3 chemical laser

International Nuclear Information System (INIS)

1975-01-01

Stable, inert, non-corrosive nitrogen trifluoride gas and an inorganic source of hydrogen or deuterium gas are used as reactants in a compact combustion driven chemical laser. Nitrogen trifluoride is introduced into the combustion chamber of a chemical laser together with a hydrogen source selected from hydrogen, hydrazine, ammonia, acetylene, or benzene and the deuterated isotopes thereof and an optional inert diluent gas wherein the nitrogen trifluoride and the hydrogen- or deuterium-source gas hypergolically reacted upon heating to initiation temperature. Dissociated products from the reaction pass into a laser cavity at supersonic velocities where they are reacted with a source gas which is the isotopic opposite of the gas introduced into the combustor and which has been heated by regenerative cooling. Excited molecules of hydrogen fluoride or deuterium fluoride produce laser radiation which leaves the optical resonator cavity transversely to the flow of gases

Dietary antioxidant synergy in chemical and biological systems.

Science.gov (United States)

Wang, Sunan; Zhu, Fan

2017-07-24

Antioxidant (AOX) synergies have been much reported in chemical ("test-tube" based assays focusing on pure chemicals), biological (tissue culture, animal and clinical models), and food systems during the past decade. Tentative synergies differ from each other due to the composition of AOX and the quantification methods. Regeneration mechanism responsible for synergy in chemical systems has been discussed. Solvent effects could contribute to the artifacts of synergy observed in the chemical models. Synergy in chemical models may hardly be relevant to biological systems that have been much less studied. Apparent discrepancies exist in understanding the molecular mechanisms in both chemical and biological systems. This review discusses diverse variables associated with AOX synergy and molecular scenarios for explanation. Future research to better utilize the synergy is suggested.

Numerical Modeling of Mixing of Chemically Reacting, Non-Newtonian Slurry for Tank Waste Retrieval

International Nuclear Information System (INIS)

Yuen, David A.; Onishi, Yasuo; Rustad, James R.; Michener, Thomas E.; Felmy, Andrew R.; Ten, Arkady A.; Hier, Catherine A.

2000-01-01

Many highly radioactive wastes will be retrieved by installing mixer pumps that inject high-speed jets to stir up the sludge, saltcake, and supernatant liquid in the tank, blending them into a slurry. This slurry will then be pumped out of the tank into a waste treatment facility. Our objectives are to investigate interactions-chemical reactions, waste rheology, and slurry mixing-occurring during the retrieval operation and to provide a scientific basis for the waste retrieval decision-making process. Specific objectives are to: (1) Evaluate numerical modeling of chemically active, non-Newtonian tank waste mixing, coupled with chemical reactions and realistic rheology; (2) Conduct numerical modeling analysis of local and global mixing of non-Newtonian and Newtonian slurries; and (3) Provide the bases to develop a scientifically justifiable, decision-making support tool for the tank waste retrieval operation

Demonstration of Hybrid DSMC-CFD Capability for Nonequilibrium Reacting Flow

Science.gov (United States)

2018-02-09

AFRL-RV-PS- TR-2018-0056 AFRL-RV-PS- TR-2018-0056 DEMONSTRATION OF HYBRID DSMC-CFD CAPABILITY FOR NONEQUILIBRIUM REACTING FLOW Thomas E...4. TITLE AND SUBTITLE Demonstration of Hybrid DSMC-CFD Capability for Nonequilibrium Reacting Flow 5a. CONTRACT NUMBER 5b. GRANT NUMBER FA9453-17-1...simulation codes. The models are based on new ab-intio rate data obtained using state -of-the-art potential energy surfaces for air species. A probability

Numerical Modeling of Mixing of Chemically Reacting, Non-Newtonian Slurry for Tank Waste Retrieval

International Nuclear Information System (INIS)

Yuen, D.A.; Onishi, Y.

2001-01-01

In the U.S. Department of Energy (DOE) complex, 100 million gallons of radioactive and chemical wastes from plutonium production are stored in 281 underground storage tanks. Retrieval of the wastes from the tanks is the first step in its ultimate treatment and disposal. Because billions of dollars are being spent on this effort, waste retrieval demands a strong scientific basis for its successful completion. As will be discussed in Section 4.2, complex interactions among waste chemical reactions, rheology, and mixing of solid and liquid tank waste (and possibly with a solvent) will occur in DSTs during the waste retrieval (mixer pump) operations. The ultimate goal of this study was to develop the ability to simulate the complex chemical and rheological changes that occur in the waste during processing for retrieval. This capability would serve as a scientific assessment tool allowing a priori evaluation of the consequences of proposed waste retrieval operations. Hanford tan k waste is a multiphase, multicomponent, high-ionic strength, and highly basic mixture of liquids and solids. Wastes stored in the 4,000-m3 DSTs will be mixed by 300-hp mixer pumps that inject high-speed (18.3 m/s) jets to stir up the sludge and supernatant liquid for retrieval. During waste retrieval operations, complex interactions occur among waste mixing, chemical reactions, and associated rheology. Thus, to determine safe and cost-effective operational parameters for waste retrieval, decisions must rely on new scientific knowledge to account for physical mixing of multiphase flows, chemical reactions, and waste rheology. To satisfy this need, we integrated a computational fluid dynamics code with state-of-the-art equilibrium and kinetic chemical models and non-Newtonian rheology (Onishi (and others) 1999). This development is unique and holds great promise for addressing the complex phenomena of tank waste retrieval. The current model is, however, applicable only to idealized tank waste

Diffusion approximations to the chemical master equation only have a consistent stochastic thermodynamics at chemical equilibrium.

Science.gov (United States)

Horowitz, Jordan M

2015-07-28

The stochastic thermodynamics of a dilute, well-stirred mixture of chemically reacting species is built on the stochastic trajectories of reaction events obtained from the chemical master equation. However, when the molecular populations are large, the discrete chemical master equation can be approximated with a continuous diffusion process, like the chemical Langevin equation or low noise approximation. In this paper, we investigate to what extent these diffusion approximations inherit the stochastic thermodynamics of the chemical master equation. We find that a stochastic-thermodynamic description is only valid at a detailed-balanced, equilibrium steady state. Away from equilibrium, where there is no consistent stochastic thermodynamics, we show that one can still use the diffusive solutions to approximate the underlying thermodynamics of the chemical master equation.

Transfer of chemicals in PWR systems: secondary side

International Nuclear Information System (INIS)

Jonas, O.

1978-01-01

Transfer of chemicals in the secondary side of pressurized water reactor systems with recirculating and once-through steam generators is considered. Chemical data on water, steam and deposit chemistry of twenty-six operating units are given and major physical-chemical processes and differences between the two systems and between fossil and PWR systems are discussed. It is concluded that the limited available data show the average water and steam chemistry to be within recommended limits, but large variations of impurity concentrations and corrosion problems encountered indicate that our knowledge of the system chemistry and chemical thermodynamics, system design, sampling, analysis and operation need improvement. (author)

Chemically reacting flow of a compressible thermally radiating two-component plasma

International Nuclear Information System (INIS)

Bestman, A.R.

1990-12-01

The paper studies the compressible flow of a hot two-component plasma in the presence of gravitation and chemical reaction in a vertical channel. For the optically thick gas approximation, closed form analytical solutions are possible. Asymptotic solutions are also obtained for the general differential approximation when the temperature of the two bounding walls are the same. In the general case the problem is reduced to the solution of standard nonlinear integral equations which can be tackled by iterative procedure. The results are discussed quantitatively. The problem may be applicable to the understanding of explosive hydrogen-burning model of solar flares. (author). 6 refs, 4 figs

Acute hepatitis due to Epstein–Barr virus with cross-reacting antibodies to cytomegalovirus

Directory of Open Access Journals (Sweden)

Asli Karadeniz

2018-01-01

Full Text Available Epstein–Barr virus (EBV is the cause of systemic infection known as infectious mononucleosis with classic presentation of fever, oropharyngitis and lymphadenitis. EBV rarely causes acute hepatitis. In this report, we present a 19-year-old patient presented with nausea, fatigue and jaundice. Her physical examination and laboratory tests revealed the diagnosis as acute hepatitis due to EBV with cross-reacting antibodies to cytomegalovirus.

Whole system chemical geothermometry

International Nuclear Information System (INIS)

Pang Zhonghe

1999-01-01

Chemical and isotopic geothermometers are equations or models based on temperature dependent chemical reactions or isotope equilibrium fractionation reactions from which equilibrium temperatures of these reactions can be calculated. The major drawback of all the conventional geothermometry methods lies in their incapability on making a judgement on the equilibrium status of the studied systems. This review will focus on two of recent approaches in this field. Zhangzhou Geothermal Field in SE China will be used as an example to demonstrate the applications

Experimental investigation of a reacting transverse jet in a high pressure oscillating vitiated crossflow

Science.gov (United States)

Fugger, Christopher A.

Staged combustion is one design approach in a gas turbine engine to reduce pollutant emission levels. In axially staged combustion, portions of the air and fuel are injected downstream of a lean premixed low NOx primary combustion zone. The gas residence time at elevated temperatures is decreased resulting in lower thermal NOx, and the reduced oxygen and high temperature vitiated primary zone flow further help to reduce pollutant emissions and quickly complete combustion. One implementation of axially staged combustion is transverse fuel jet injection. An important consideration for staged combustion systems, though, is how the primary and secondary combustion zones can couple through the acoustic resonances of the chamber. These couplings can lead to additional source terms that pump energy into the resonant acoustic field and help sustain the high-amplitude combustor pressure oscillations. An understanding of these couplings is important so that it may be possible to design a secondary combustion system that provides inherent damping to the combustor system. To systematically characterize the coupling of a reacting jet in unsteady crossflow in detail, the effects of an an unsteady pressure flowfield and an unsteady velocity flowfield are separately investigated. An optically accessible resonant combustion chamber was designed and built as part of this work to generate a standing wave unsteady vitiated crossflow at a chamber pressure of 0.9 MPa. The location of transverse jet injection corresponds to one of two locations, where one location is the pressure node and the other location the pressure anti-node of the resonant chamber acoustic mode. The injection location is optically accessible, and the dynamic interactions between the transverse jet flow and the 1st and 2nd axial combustor modes are measured using 10 kHz OH-PLIF and 2D PIV. This document analyzes five test cases: two non-reacting jets and three reacting jets. All cases correspond to jet injection

Improving Resilience to Emergencies through Advanced Cyber Technologies: the I-REACT project

Directory of Open Access Journals (Sweden)

Claudia Maltoni

2017-08-01

be equipped with essential tools for early warning and response. At the same time, private companies could leverage specific set of I-REACT components to improve their business, when linked to disaster management. Overall, I-REACT aims to be a European-wide contribution to build more secure and resilient societies to disasters.

KEEFEKTIFAN STRATEGI REACT DITINJAU DARI PRESTASI BELAJAR, KEMAMPUAN PENYELESAIAN MASALAH, KONEKSI MATEMATIS, SELF EFFICACY

Directory of Open Access Journals (Sweden)

Runtyani Irjayanti Putri

2015-11-01

Full Text Available Penelitian ini bertujuan untuk: (1 mendeskripsikan keefektifan strategi pembelajaran REACT pada pembelajaran turunan fungsi ditinjau dari prestasi belajar matematika, kemampuan penyelesaian masalah matematis, kemampuan koneksi matematis, dan Self efficacy siswa SMA Negeri 4 Magelang, (2 menentukan strategi pembelajaran yang lebih efektif diantara strategi REACT dan pembelajaran konvensional pada pembelajaran turunan fungsi ditinjau dari aspek prestasi belajar matematika, kemampuan penyelesaian masalah matematis, kemampuan koneksi matematis, dan Self efficacy siswa SMA Negeri 4 Magelang. Penelitian ini adalah penelitian quasi experiment. Teknik pengumpulan data yang digunakan adalah teknik tes dan nontes. Teknik analisis data yang digunakan adalah uji one sample t-test, uji T2 Hotelling’s, dan uji t-Bonferroni. Hasil penelitian menunjukkan bahwa: (1 strategi pembelajaran REACT efektif pada pembelajaran turunan fungsi ditinjau dari prestasi belajar matematika, kemampuan penyelesaian masalah matematis, kemampuan koneksi matematis, dan Self efficacy siswa SMA Negeri 4 Magelang, dan (2 strategi pembelajaran REACT lebih efektif daripada pembelajaran konvensional pada pembelajaran turunan fungsi ditinjau dari aspek prestasi belajar matematika, kemampuan penyelesaian masalah matematis, kemampuan koneksi matematis, dan Self efficacy siswa SMA Negeri 4 Magelang. Kata Kunci: strategi REACT, prestasi belajar, kemampuan penyelesaian masalah matematis, kemampuan koneksi matematis, dan Self efficacy siswa SMA   THE EFFECTIVENESS OF REACT STRATEGY VIEWED FROM LEARNING ACHIEVEMENT, PROBLEM SOLVING ABILITY, MATHEMATICAL CONNECTION, SELF EFFICACY Abstract The aims of this study are to: (1 to describe the effectiveness of the REACT strategy viewed from Mathematics Learning Achievement, Mathematics Problem Solving Ability, Mathematics Connection Ability, and Student Self efficacy of State Senior High School 4 Magelang Students, and (2 determine a more effective

Chemical detection, identification, and analysis system

International Nuclear Information System (INIS)

Morel, R.S.; Gonzales, D.; Mniszewski, S.

1990-01-01

The chemical detection, identification, and analysis system (CDIAS) has three major goals. The first is to display safety information regarding chemical environment before personnel entry. The second is to archive personnel exposure to the environment. Third, the system assists users in identifying the stage of a chemical process in progress and suggests safety precautions associated with that process. In addition to these major goals, the system must be sufficiently compact to provide transportability, and it must be extremely simple to use in order to keep user interaction at a minimum. The system created to meet these goals includes several pieces of hardware and the integration of four software packages. The hardware consists of a low-oxygen, carbon monoxide, explosives, and hydrogen sulfide detector; an ion mobility spectrometer for airborne vapor detection; and a COMPAQ 386/20 portable computer. The software modules are a graphics kernel, an expert system shell, a data-base management system, and an interface management system. A supervisory module developed using the interface management system coordinates the interaction of the other software components. The system determines the safety of the environment using conventional data acquisition and analysis techniques. The low-oxygen, carbon monoxide, hydrogen sulfide, explosives, and vapor detectors are monitored for hazardous levels, and warnings are issued accordingly

Process to separate alkali metal salts from alkali metal reacted hydrocarbons

Energy Technology Data Exchange (ETDEWEB)

Gordon, John Howard; Alvare, Javier; Larsen, Dennis; Killpack, Jeff

2017-06-27

A process to facilitate gravimetric separation of alkali metal salts, such as alkali metal sulfides and polysulfides, from alkali metal reacted hydrocarbons. The disclosed process is part of a method of upgrading a hydrocarbon feedstock by removing heteroatoms and/or one or more heavy metals from the hydrocarbon feedstock composition. This method reacts the oil feedstock with an alkali metal and an upgradant hydrocarbon. The alkali metal reacts with a portion of the heteroatoms and/or one or more heavy metals to form an inorganic phase containing alkali metal salts and reduced heavy metals, and an upgraded hydrocarbon feedstock. The inorganic phase may be gravimetrically separated from the upgraded hydrocarbon feedstock after mixing at a temperature between about 350.degree. C. to 400.degree. C. for a time period between about 15 minutes and 2 hours.

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

Prediction of reacting atoms for the major biotransformation reactions of organic xenobiotics.

Science.gov (United States)

Rudik, Anastasia V; Dmitriev, Alexander V; Lagunin, Alexey A; Filimonov, Dmitry A; Poroikov, Vladimir V

2016-01-01

The knowledge of drug metabolite structures is essential at the early stage of drug discovery to understand the potential liabilities and risks connected with biotransformation. The determination of the site of a molecule at which a particular metabolic reaction occurs could be used as a starting point for metabolite identification. The prediction of the site of metabolism does not always correspond to the particular atom that is modified by the enzyme but rather is often associated with a group of atoms. To overcome this problem, we propose to operate with the term "reacting atom", corresponding to a single atom in the substrate that is modified during the biotransformation reaction. The prediction of the reacting atom(s) in a molecule for the major classes of biotransformation reactions is necessary to generate drug metabolites. Substrates of the major human cytochromes P450 and UDP-glucuronosyltransferases from the Biovia Metabolite database were divided into nine groups according to their reaction classes, which are aliphatic and aromatic hydroxylation, N- and O-glucuronidation, N-, S- and C-oxidation, and N- and O-dealkylation. Each training set consists of positive and negative examples of structures with one labelled atom. In the positive examples, the labelled atom is the reacting atom of a particular reaction that changed adjacency. Negative examples represent non-reacting atoms of a particular reaction. We used Labelled Multilevel Neighbourhoods of Atoms descriptors for the designation of reacting atoms. A Bayesian-like algorithm was applied to estimate the structure-activity relationships. The average invariant accuracy of prediction obtained in leave-one-out and 20-fold cross-validation procedures for five human isoforms of cytochrome P450 and all isoforms of UDP-glucuronosyltransferase varies from 0.86 to 0.99 (0.96 on average). We report that reacting atoms may be predicted with reasonable accuracy for the major classes of metabolic reactions

Development and Validation of Chemical Kinetic Mechanism Reduction Scheme for Large-Scale Mechanisms

DEFF Research Database (Denmark)

Poon, Hiew Mun; Ng, Hoon Kiat; Gan, Suyin

2014-01-01

This work is an extension to a previously reported work on chemical kinetic mechanism reduction scheme for large-scale mechanisms. Here, Perfectly Stirred Reactor (PSR) was added as a criterion of data source for mechanism reduction instead of using only auto-ignition condition. As a result......) simulations were performed to study the spray combustion phenomena within a constant volume bomb. Both non-reacting and reacting conditions were applied in this study. Liquid and vapor penetration lengths were replicated for non-reacting diesel spray. For reacting diesel spray, both ignition delay and lift......-off length were simulated. The simulation results were then compared to the experimental data of Sandia National Laboratories and No. 2 Diesel Fuel (D2) was designated as the reference fuel. Both liquid and vapor penetrations for non-reacting condition were well-matched, while ignition delay was advanced...

Numerical simulation of reacting and non-reacting flow in a combustion chamber; Numerisk simulering av reagerande och icke-reagerande stroemning i en braennkammare

Energy Technology Data Exchange (ETDEWEB)

Borg, A.; Revstedt, J.

1996-04-01

The purpose of this work has been to do a preliminary study of how well numerical calculations with different turbulence models can predict the flow and temperature fields of a strongly swirling and combusting flow in an experimental combustion chamber and to see which parameters in the mathematical model are the most important. The combustion chamber on which we have done the calculations is called Validation Rig II and was designed by Volvo Aero Corporation. The main part of the study has been carried out on a non-reacting flow but some work has also been done on reacting flow. In most cases it has not been meaningful to compare the calculations with the measurements because they differ quite a lot from each other. For the non-reacting case the following investigations have been made: * How the solution differs for different turbulence models, * The solutions sensitivity to inlet boundary conditions, * How different types of leakage disturb the flow, and * The difference in results between two different CFD-codes, the commercial code CFDS-Flow3D and a code developed at the department of fluid mechanics. For the reacting cases we have studied the influence of: * one or two reaction steps, * the effects of a change in reaction rate, * the influence of thermal radiation, and * the effects of changing the boundary conditions for temperature on the walls. The results from these calculations show that the inlet turbulence intensity has very little effect on the values of the turbulent quantities as well as the velocity profiles at the outlet. Changing the turbulence model or the outlet boundary conditions gives some change in velocity profiles at the outlet but only marginal effects on the swirl number. 21 refs, 54 figs, 19 tabs

Method for producing chemical energy

Science.gov (United States)

Jorgensen, Betty S.; Danen, Wayne C.

2004-09-21

Fluoroalkylsilane-coated metal particles having a central metal core, a buffer layer surrounding the core, and a fluoroalkylsilane layer attached to the buffer layer are prepared by combining a chemically reactive fluoroalkylsilane compound with an oxide coated metal particle having a hydroxylated surface. The resulting fluoroalkylsilane layer that coats the particles provides them with excellent resistance to aging. The particles can be blended with oxidant particles to form energetic powder that releases chemical energy when the buffer layer is physically disrupted so that the reductant metal core can react with the oxidant.

Study of Intelligent Secure Chemical Inventory Management System

Science.gov (United States)

Shukran, Mohd Afizi Mohd; Naim Abdullah, Muhammad; Nazri Ismail, Mohd; Maskat, Kamaruzaman; Isa, Mohd Rizal Mohd; Shahfee Ishak, Muhammad; Adib Khairuddin, Muhamad

2017-08-01

Chemical inventory management system has been experiencing a new revolution from traditional inventory system which is manual to an automated inventory management system. In this paper, some review of the classic and modern approaches to chemical inventory management system has been discussed. This paper also describe about both type of inventory management. After a comparative analysis of the traditional method and automated method, it can be said that both methods have some distinctive characteristics. Moreover, the automated inventory management method has higher accuracy of calculation because the calculations are handled by software, eliminating possible errors and saving time. The automated inventory system also allows users and administrators to track the availability, location and consumption of chemicals. The study of this paper can provide forceful review analysis support for the chemical inventory management related research.

29 CFR 1910.161 - Fixed extinguishing systems, dry chemical.

Science.gov (United States)

2010-07-01

... 29 Labor 5 2010-07-01 2010-07-01 false Fixed extinguishing systems, dry chemical. 1910.161 Section... § 1910.161 Fixed extinguishing systems, dry chemical. (a) Scope and application. This section applies to all fixed extinguishing systems, using dry chemical as the extinguishing agent, installed to meet a...

Engineered Barrier System: Physical and Chemical Environment

International Nuclear Information System (INIS)

Dixon, P.

2004-01-01

The conceptual and predictive models documented in this Engineered Barrier System: Physical and Chemical Environment Model report describe the evolution of the physical and chemical conditions within the waste emplacement drifts of the repository. The modeling approaches and model output data will be used in the total system performance assessment (TSPA-LA) to assess the performance of the engineered barrier system and the waste form. These models evaluate the range of potential water compositions within the emplacement drifts, resulting from the interaction of introduced materials and minerals in dust with water seeping into the drifts and with aqueous solutions forming by deliquescence of dust (as influenced by atmospheric conditions), and from thermal-hydrological-chemical (THC) processes in the drift. These models also consider the uncertainty and variability in water chemistry inside the drift and the compositions of introduced materials within the drift. This report develops and documents a set of process- and abstraction-level models that constitute the engineered barrier system: physical and chemical environment model. Where possible, these models use information directly from other process model reports as input, which promotes integration among process models used for total system performance assessment. Specific tasks and activities of modeling the physical and chemical environment are included in the technical work plan ''Technical Work Plan for: In-Drift Geochemistry Modeling'' (BSC 2004 [DIRS 166519]). As described in the technical work plan, the development of this report is coordinated with the development of other engineered barrier system analysis model reports

MP Salsa: a finite element computer program for reacting flow problems. Part 1--theoretical development

Energy Technology Data Exchange (ETDEWEB)

Shadid, J.N.; Moffat, H.K.; Hutchinson, S.A.; Hennigan, G.L.; Devine, K.D.; Salinger, A.G.

1996-05-01

The theoretical background for the finite element computer program, MPSalsa, is presented in detail. MPSalsa is designed to solve laminar, low Mach number, two- or three-dimensional incompressible and variable density reacting fluid flows on massively parallel computers, using a Petrov-Galerkin finite element formulation. The code has the capability to solve coupled fluid flow, heat transport, multicomponent species transport, and finite-rate chemical reactions, and to solver coupled multiple Poisson or advection-diffusion- reaction equations. The program employs the CHEMKIN library to provide a rigorous treatment of multicomponent ideal gas kinetics and transport. Chemical reactions occurring in the gas phase and on surfaces are treated by calls to CHEMKIN and SURFACE CHEMKIN, respectively. The code employs unstructured meshes, using the EXODUS II finite element data base suite of programs for its input and output files. MPSalsa solves both transient and steady flows by using fully implicit time integration, an inexact Newton method and iterative solvers based on preconditioned Krylov methods as implemented in the Aztec solver library.

Comparison of improved finite-difference WENO schemes for the implicit large eddy simulation of turbulent non-reacting and reacting high-speed shear flows

International Nuclear Information System (INIS)

Zhao, S.; Lardjane, N.; Fedioun, I.

2014-01-01

Improved WENO schemes, Z, M, and their combination MZ, originally designed to capture sharper discontinuities than the classical fifth order Jiang-Shu scheme does, are evaluated for the purpose of implicit large eddy simulation of free shear flows. 1D Fourier analysis of errors reveals the built-in filter and dissipative properties of the schemes, which are subsequently applied to the canonical Rayleigh-Taylor and Taylor-Green flows. Large eddy simulations of a transonic non-reacting and a supersonic reacting air/H2 jets are then performed at resolution 128 * 128 * 512, showing no significant difference in the flow statistics. However, the computational time varies from one scheme to the other, the Z scheme providing the smaller wall-time due to larger allowed time steps. (authors)

Engineered Barrier System: Physical and Chemical Environment

Energy Technology Data Exchange (ETDEWEB)

P. Dixon

2004-04-26

The conceptual and predictive models documented in this Engineered Barrier System: Physical and Chemical Environment Model report describe the evolution of the physical and chemical conditions within the waste emplacement drifts of the repository. The modeling approaches and model output data will be used in the total system performance assessment (TSPA-LA) to assess the performance of the engineered barrier system and the waste form. These models evaluate the range of potential water compositions within the emplacement drifts, resulting from the interaction of introduced materials and minerals in dust with water seeping into the drifts and with aqueous solutions forming by deliquescence of dust (as influenced by atmospheric conditions), and from thermal-hydrological-chemical (THC) processes in the drift. These models also consider the uncertainty and variability in water chemistry inside the drift and the compositions of introduced materials within the drift. This report develops and documents a set of process- and abstraction-level models that constitute the engineered barrier system: physical and chemical environment model. Where possible, these models use information directly from other process model reports as input, which promotes integration among process models used for total system performance assessment. Specific tasks and activities of modeling the physical and chemical environment are included in the technical work plan ''Technical Work Plan for: In-Drift Geochemistry Modeling'' (BSC 2004 [DIRS 166519]). As described in the technical work plan, the development of this report is coordinated with the development of other engineered barrier system analysis model reports.

Nb3Sn dipole magnet reacted after winding

International Nuclear Information System (INIS)

Taylor, C.; Scanlan, R.; Peters, C.; Wolgast, R.; Gilbert, W.; Hassenzahl, W.; Meuser, R.; Rechen, J.

1984-09-01

A 5 cm bore dia., 1-m-long dipole model magnet was constructed by winding un-reacted cable, followed by reaction and epoxy-impregnation. Experience and test results are described on the 1.7 mm dia. internal-tin wire, the eleven-strand flattened cable, fiberglass insulation, and construction of the magnet. Each half of the magnet has two double-pancake-type windings that were reacted in a single operation. The two double-pancakes were then separately vacuum impregnated after soldering the flexible Nb-Ti leads to the Nb 3 Sn conductors. No iron flux return yoke was used. In initial tests a central field of 8.0 T was reached at 4.4 K. However, evidence from training behavior, and 1.8 K tests indicate that premature quenching, rather than critical current of the cable, limited the field intensity. The magnet was reassembled and more rigidly clamped; additional test results are reported

A proposed chemical mechanism for biological phosphate removal ...

African Journals Online (AJOL)

This paper presents an alternative for the ";all biological"; phosphate removal model. It is postulated that a chemical substance in wastewater reacts with orthophosphate under anaerobic conditions to make the so-called luxury uptake of phosphorus possible in biological nutrient removal (BNR) activated sludge plants.

Motivation, procedures and aims of reacting plasma experiments

International Nuclear Information System (INIS)

Miyahara, Akira

1982-01-01

A project of reacting plasma experiment (R-project) was proposed at the Institute of Plasma Physics (IPP), Nagoya University. It is necessary to bridge plasma physics and fusion engineering by means of a messenger wire like burning plasma experiment. This is a motivation of the R-project. The university linkage organization of Japan for fusion engineering category carried out a lot of contribution to R-tokamak design. The project consists of four items, namely, R-tokamak design, research and development (R and D), site and facilities, and international collaboration. The phase 1 experiment (R 1 - phase) corresponds to burning plasma experiment without D + T fuel, while the phase-2 experiment (R 2 -phase) with D + T fuel. One reference design was finished. Intensive efforts have been carried out by the R and D team on the following items, wall material, vacuum system, tritium system, neutronics, remote control system, pulsed superconducting magnet development, negative ion source, and alpha-particle diagnostics. The problems concerning site and major facilities are also important, because tritium handling, neutron and gamma-ray sky shines and the activation of devices cause impact to surrounding area. The aims of burning plasma experiment are to enter tritium into the fusion device, and to study burning plasma physics. (Kato, T.)

A sequential-move game for enhancing safety and security cooperation within chemical clusters

International Nuclear Information System (INIS)

Pavlova, Yulia; Reniers, Genserik

2011-01-01

The present paper provides a game theoretic analysis of strategic cooperation on safety and security among chemical companies within a chemical industrial cluster. We suggest a two-stage sequential move game between adjacent chemical plants and the so-called Multi-Plant Council (MPC). The MPC is considered in the game as a leader player who makes the first move, and the individual chemical companies are the followers. The MPC's objective is to achieve full cooperation among players through establishing a subsidy system at minimum expense. The rest of the players rationally react to the subsidies proposed by the MPC and play Nash equilibrium. We show that such a case of conflict between safety and security, and social cooperation, belongs to the 'coordination with assurance' class of games, and we explore the role of cluster governance (fulfilled by the MPC) in achieving a full cooperative outcome in domino effects prevention negotiations. The paper proposes an algorithm that can be used by the MPC to develop the subsidy system. Furthermore, a stepwise plan to improve cross-company safety and security management in a chemical industrial cluster is suggested and an illustrative example is provided.

A polarization system for persistent chemical detection

Science.gov (United States)

Craven-Jones, Julia; Appelhans, Leah; Couphos, Eric; Embree, Todd; Finnegan, Patrick; Goldstein, Dennis; Karelitz, David; LaCasse, Charles; Luk, Ting S.; Mahamat, Adoum; Massey, Lee; Tanbakuchi, Anthony; Washburn, Cody; Vigil, Steven

2015-09-01

We report on the development of a prototype polarization tag based system for detecting chemical vapors. The system primarily consists of two components, a chemically sensitive tag that experiences a change in its optical polarization properties when exposed to a specific chemical of interest, and an optical imaging polarimeter that is used to measure the polarization properties of the tags. Although the system concept could be extended to other chemicals, for the initial system prototype presented here the tags were developed to be sensitive to hydrogen fluoride (HF) vapors. HF is used in many industrial processes but is highly toxic and thus monitoring for its presence and concentration is often of interest for personnel and environmental safety. The tags are periodic multilayer structures that are produced using standard photolithographic processes. The polarimetric imager has been designed to measure the degree of linear polarization reflected from the tags in the short wave infrared. By monitoring the change in the reflected polarization signature from the tags, the polarimeter can be used to determine if the tag was exposed to HF gas. In this paper, a review of the system development effort and preliminary test results are presented and discussed, as well as our plan for future work.

How do patients and providers react to different incentives in the Chinese multiple health security systems?

Science.gov (United States)

Zhang, Chun-Yu; Hashimoto, Hideki

2015-03-05

China has achieved universal health insurance coverage. This study examined how patients and hospitals react to the different designs of the plans and to monitoring of patients by the local authority in the Chinese multiple health security schemes. The sample for analysis consisted of 1006 orthopedic inpatients who were admitted between January and December 2011 at a tertiary teaching hospital located in Beijing. We conducted general linear regression analyses to investigate whether medical expenditure and length of stay differed according to the different incentives. Patients under plans with lower copayment rates consumed significantly more medication compared with those under plans with higher copayment rates. Under plans with an annual ceiling for insurance coverage, patients spent significantly more in the second half of the year than in the first half of the year. The length of stay was shorter among patients when there were government monitoring and a penalty to the hospital service provider. Our results indicate that the different designs and monitoring of the health security systems in China cause opportunistic behavior by patients and providers. Reformation is necessary to reduce those incentives, and improve equity and efficiency in healthcare use.

Self-Calibrating, Variable-Flow Pumping System

Science.gov (United States)

Walls, Joe T.

1994-01-01

Pumping system provides accurate, controlled flows of two chemical liquids mixed in spray head and react to form rigid or flexible polyurethane or polyisocyanurate foam. Compatible with currently used polyurethane-based coating materials and gas-bubble-forming agents (called "blowing agents" in industry) and expected to be compatible with materials that used in near future. Handles environmentally acceptable substitutes for chlorofluorocarbon foaming agents.

Chemical vapor deposited fiber coatings and chemical vapor infiltrated ceramic matrix composites

Energy Technology Data Exchange (ETDEWEB)

Kmetz, M.A.

1992-01-01

Conventional Chemical Vapor Deposition (CVD) and Organometallic Chemical Vapor Deposition (MOCVD) were employed to deposit a series of interfacial coatings on SiC and carbon yarn. Molybdenum, tungsten and chromium hexacarbonyls were utilized as precursors in a low temperature (350[degrees]C) MOCVD process to coat SiC yarn with Mo, W and Cr oxycarbides. Annealing studies performed on the MoOC and WOC coated SiC yarns in N[sub 2] to 1,000[degrees]C establish that further decomposition of the oxycarbides occurred, culminating in the formation of the metals. These metals were then found to react with Si to form Mo and W disilicide coatings. In the Cr system, heating in N[sub 2] above 800[degrees]C resulted in the formation of a mixture of carbides and oxides. Convention CVD was also employed to coat SiC and carbon yarn with C, Bn and a new interface designated BC (a carbon-boron alloy). The coated tows were then infiltrated with SiC, TiO[sub 2], SiO[sub 2] and B[sub 4]C by a chemical vapor infiltration process. The B-C coatings were found to provide advantageous interfacial properties over carbon and BN coatings in several different composite systems. The effectiveness of these different coatings to act as a chemically inert barrier layer and their relationship to the degree of interfacial debonding on the mechanical properties of the composites were examined. The effects of thermal stability and strength of the coated fibers and composites were also determined for several difference atmospheres. In addition, a new method for determining the tensile strength of the as-received and coated yarns was also developed. The coated fibers and composites were further characterized by AES, SEM, XPS, IR and X-ray diffraction analysis.

Optimal stretching in the reacting wake of a bluff body.

Science.gov (United States)

Wang, Jinge; Tithof, Jeffrey; Nevins, Thomas D; Colón, Rony O; Kelley, Douglas H

2017-12-01

We experimentally study spreading of the Belousov-Zhabotinsky reaction behind a bluff body in a laminar flow. Locations of reacted regions (i.e., regions with high product concentration) correlate with a moderate range of Lagrangian stretching and that range is close to the range of optimal stretching previously observed in topologically different flows [T. D. Nevins and D. H. Kelley, Phys. Rev. Lett. 117, 164502 (2016)]. The previous work found optimal stretching in a closed, vortex dominated flow, but this article uses an open flow and only a small area of appreciable vorticity. We hypothesize that optimal stretching is common in advection-reaction-diffusion systems with an excitation threshold, including excitable and bistable systems, and that the optimal range depends on reaction chemistry and not on flow shape or characteristic speed. Our results may also give insight into plankton blooms behind islands in ocean currents.

A stochastic model of particle dispersion in turbulent reacting gaseous environments

Science.gov (United States)

Sun, Guangyuan; Lignell, David; Hewson, John

2012-11-01

We are performing fundamental studies of dispersive transport and time-temperature histories of Lagrangian particles in turbulent reacting flows. The particle-flow statistics including the full particle temperature PDF are of interest. A challenge in modeling particle motions is the accurate prediction of fine-scale aerosol-fluid interactions. A computationally affordable stochastic modeling approach, one-dimensional turbulence (ODT), is a proven method that captures the full range of length and time scales, and provides detailed statistics of fine-scale turbulent-particle mixing and transport. Limited results of particle transport in ODT have been reported in non-reacting flow. Here, we extend ODT to particle transport in reacting flow. The results of particle transport in three flow configurations are presented: channel flow, homogeneous isotropic turbulence, and jet flames. We investigate the functional dependence of the statistics of particle-flow interactions including (1) parametric study with varying temperatures, Reynolds numbers, and particle Stokes numbers; (2) particle temperature histories and PDFs; (3) time scale and the sensitivity of initial and boundary conditions. Flow statistics are compared to both experimental measurements and DNS data.

Large Eddy Simulation of Spatially Developing Turbulent Reacting Shear Layers with the One-Dimensional Turbulence Model

Science.gov (United States)

Hoffie, Andreas Frank

model. The chemical reaction is simulated with a global single-step, second-order equilibrium reaction with an Arrhenius reaction rate. The two benchmark cases of constant density reacting and variable density non-reacting shear layers used to determine ODT parameters yield perfect agreement with regards to first and second-order flow statistics as well as shear layer growth rate. The variable density non-reacting shear layer also serves as a testing case for the LES-ODT model to simulate passive scalar mixing. The variable density, reacting shear layer cases only agree reasonably well and indicate that more work is necessary to improve variable density coupling of ODT and LES. The disagreement is attributed to the fact that the ODT filtered density is kept constant across the Runge-Kutta steps. Furthermore, a more in-depth knowledge of large scale and subgrid turbulent kinetic energy (TKE) spectra at several downstream locations as well as TKE budgets need to be studied to obtain a better understanding about the model as well as about the flow under investigation. The local Reynolds number based on the one-percent thickness at the exit is Redelta ≈ 5300, for the constant density reacting and for the variable density non-reacting case. For the variable density reacting shear layer, the Reynolds number based on the 1% thickness is Redelta ≈ 2370. The variable density reacting shear layers show suppressed growth rates due to density variations caused by heat release. This has also been reported in literature. A Lewis number parameter study is performed to extract non-unity Lewis number effects. An increase in the Lewis number leads to a further suppression of the growth rate, however to an increase spread of second-order flow statistics. Major focus and challenge of this work is to improve and advance the three-dimensional coupling of the one-dimensional ODT domains while keeping the solution correct. This entails major restructuring of the model. The turbulent

Temperature lowering in cryogenic chemical-synthesis techniques and system

International Nuclear Information System (INIS)

Martinez, H.E.; Nelson, T.O.; Vikdal, L.N.

1993-01-01

When evaluating a chemical synthesis process for a reaction that occurs on the cryogenically cooled walls, it is sometimes necessary to reduce the wall temperatures to enhance the chemical process. To evaluate the chemical process at lower than atmospheric boiling of liquid nitrogen, we built a system and used it to reduce the temperature of the liquid nitrogen. The technique of lowering the liquid nitrogen temperature by reducing the pressure of the boil-off is established knowledge. This paper presents the engineering aspects of the system, design features, equipment requirements, methods of control, and results of the chemical synthesis. The heat input to the system was ∼400 watts, placing a relatively large demand on the pumping system. Our system is a scale-up of the small laboratory experiment, and it provides the information needed to design an effective system. The major problem encountered was the large quantity of liquid escaping the system during the processing, placing a large gas load on the vacuum system

Chemical heat pump and chemical energy storage system

Science.gov (United States)

Clark, Edward C.; Huxtable, Douglas D.

1985-08-06

A chemical heat pump and storage system employs sulfuric acid and water. In one form, the system includes a generator and condenser, an evaporator and absorber, aqueous acid solution storage and water storage. During a charging cycle, heat is provided to the generator from a heat source to concentrate the acid solution while heat is removed from the condenser to condense the water vapor produced in the generator. Water is then stored in the storage tank. Heat is thus stored in the form of chemical energy in the concentrated acid. The heat removed from the water vapor can be supplied to a heat load of proper temperature or can be rejected. During a discharge cycle, water in the evaporator is supplied with heat to generate water vapor, which is transmitted to the absorber where it is condensed and absorbed into the concentrated acid. Both heats of dilution and condensation of water are removed from the thus diluted acid. During the discharge cycle the system functions as a heat pump in which heat is added to the system at a low temperature and removed from the system at a high temperature. The diluted acid is stored in an acid storage tank or is routed directly to the generator for reconcentration. The generator, condenser, evaporator, and absorber all are operated under pressure conditions specified by the desired temperature levels for a given application. The storage tanks, however, can be maintained at or near ambient pressure conditions. In another form, the heat pump system is employed to provide usable heat from waste process heat by upgrading the temperature of the waste heat.

Culturing Security System of Chemical Laboratory in Indonesia

Directory of Open Access Journals (Sweden)

Eka Dian Pusfitasari

2017-04-01

Full Text Available Indonesia has experiences on the lack of chemical security such as: a number of bombing terrors and hazardous chemicals found in food. Bomb used in terror is a homemade bomb made from chemicals which are widely spread in the research laboratories such as a mixture of pottasium chlorate, sulphur, and alumunium. Therefore, security of chemicals should be implemented to avoid the misused of the chemicals. Although it has experienced many cases of the misuse of chemicals, and many regulations and seminars related to chemical security have been held, but the implementation of chemical security is still a new thing for Indonesian citizens. The evident is coming from the interviews conducted in this study. Questions asked in this interview/survey included: the implementation of chemical safety and chemical security in laboratory; chemical inventory system and its regulation; and training needed for chemical security implementation. Respondents were basically a researcher from Government Research Institutes, University laboratories, senior high school laboratories, and service laboratories were still ambiguous in distinguishing chemical safety and chemical security. Because of this condition, most Indonesia chemical laboratories did not totally apply chemical security system. Education is very important step to raise people awareness and address this problem. Law and regulations should be sustained by all laboratory personnel activities to avoid chemical diversion to be used for harming people and environment. The Indonesia Government could also develop practical guidelines and standards to be applied to all chemical laboratories in Indonesia. These acts can help Government’s efforts to promote chemical security best practices which usually conducted by doing seminars and workshop.

Keefektifan Strategi Pembelajaran React Pada Kemampuan Siswa Kelas VII Aspek Komunikasi Matematis

Directory of Open Access Journals (Sweden)

A.T. Arifin

2014-06-01

Full Text Available AbstrakTujuan penelitian ini adalah mengetahui pembelajaran dengan strategi REACT efektif ter-hadap kemampuan komunikasi matematis siswa. Metode pengumpulan data dilakukan de-ngan metode dokumentasi, tes, dan observasi. Hasil uji proporsi menunjukkan bahwa hasil belajar siswa kelas eksperimen pada aspek kemampuan komunikasi matematis telah men-capai ketuntasan klasikal, mencapai lebih dari 80 % yaitu sebesar 96,7%. Dilihat dari nilai rata-rata tes kemampuan komunikasi matematis kelas eksperimen  adalah 83,61 sedangkan kelas kontrol adalah 73,79 dapat disimpulkan bahwa kemampuan komunikasi matematis siswa kelas eksperimen lebih baik daripada kemampuan komunikasi matematis siswa kon-trol. Hasil penelitian menunjukkan bahwa penerapan strategi pembelajaran REACT efektif terhadap kemampuan komunikasi matematis siswa materi segiempat kelas VII SMP Negeri 1 Gembong. Kata kunci:      keefektifan, kemampuan komunikasi matematis, Relating Experiencing Applying Cooperating Transferring (REACT  AbstractThe purpose of this study was to determine the effectiveness of the application of REACT learning strategy approach to mathematic communication ability of students. Methods of data collection is done by the method of documentation, testing, and observation. The test results showed that the proportion of student learning outcomes in the experimental class with the aspects of mathematic communication ability has reached the classical completeness, reached more than 80% is equal to 96.7%. Judging from the value of the average test learners' ability to mathematic communication experimental class was 83.61 while the control class is 73.79 it can be concluded that the mathematic communication skills of learners experimental classes are better than mathematic communication abilities of learners control class. The results showed that the application of REACT learning strategy approach effective to mathematic communication abilities of students of class VII

ENGINEERED BARRIER SYSTEM: PHYSICAL AND CHEMICAL ENVIRONMENT

International Nuclear Information System (INIS)

Jarek, R.

2004-01-01

The purpose of this report is to describe the evolution of the physical and chemical environmental conditions within the waste emplacement drifts of the repository, including the drip shield and waste package surfaces. The abstraction model is used in the total system performance assessment for the license application (TSPA LA) to assess the performance of the engineered barrier system and the waste form. This report develops and documents a set of these abstraction-level models that describe the engineered barrier system physical and chemical environment. Where possible, these models use information directly from other reports as input, which promotes integration among process models used for TSPA-LA. Specific tasks and activities of modeling the physical and chemical environment are included in ''Technical Work Plan for: Near-Field Environment and Transport In-Drift Geochemistry Model Report Integration'' (BSC 2004 [DIRS 171156], Section 1.2.2). As described in the technical work plan, the development of this report is coordinated with the development of other engineered barrier system reports

ENGINEERED BARRIER SYSTEM: PHYSICAL AND CHEMICAL ENVIRONMENT

International Nuclear Information System (INIS)

G.H. Nieder-Westermann

2005-01-01

The purpose of this report is to describe the evolution of the physical and chemical environmental conditions within the waste emplacement drifts of the repository, including the drip shield and waste package surfaces. The abstraction model is used in the total system performance assessment for the license application (TSPA LA) to assess the performance of the engineered barrier system and the waste form. This report develops and documents a set of these abstraction-level models that describe the engineered barrier system physical and chemical environment. Where possible, these models use information directly from other reports as input, which promotes integration among process models used for TSPA-LA. Specific tasks and activities of modeling the physical and chemical environment are included in ''Technical Work Plan for: Near-Field Environment and Transport In-Drift Geochemistry Model Report Integration'' (BSC 2004 [DIRS 171156], Section 1.2.2). As described in the technical work plan, the development of this report is coordinated with the development of other engineered barrier system reports

Equilibrium Constant as Solution to the Open Chemical Systems

OpenAIRE

Zilbergleyt, B.

2008-01-01

According to contemporary views, equilibrium constant is relevant only to true thermodynamic equilibria in isolated systems with one chemical reaction. The paper presents a novel formula that ties-up equilibrium constant and chemical system composition at any state, isolated or open as well. Extending the logarithmic logistic map of the Discrete Thermodynamics of Chemical Equilibria, this formula maps the system population at isolated equilibrium into the population at any open equilibrium at...

Investigation of Na-CO{sub 2} Reaction with Initial Reaction in Various Reacting Surface

Energy Technology Data Exchange (ETDEWEB)

Kim, Hyun Su; Park, Gunyeop; Kim, Soo Jae; Park, Hyun Sun; Kim, Moo Hwan [POSTECH, Pohang (Korea, Republic of); Wi, Myung-Hwan [KAERI, Daejeon (Korea, Republic of)

2015-10-15

The reaction products that cause oxidation and erosion are threaten the heat transfer tubes so that it is necessary to investigate Na-CO{sub 2} reaction according to various experimental parameter. Unlike SWR, Na-CO{sub 2} reaction is more complex to deal with reaction kinetics. Since a comprehensive understanding of Na-CO{sub 2} reaction mechanism is crucial for the safety analysis, the reaction phenomenon under the various conditions was investigated. The current issue is to make a database for developing computational code for CO{sub 2} gas leak situation because it is experimentally difficult to analyze the actual accident situation. Most studies on Na-CO{sub 2} interaction reports that chemical reaction is getting vigorous as temperature increased and reactivity is sensitive as temperature change between 400 .deg. C and 600 .deg. C. Therefore, temperature range is determined based on the operating condition (450 - 500 .deg. C) of KALIMER-600 employed as supercritical CO{sub 2} brayton cycle energy conversion system for Na-CO{sub 2} heat exchanger. And next parameter is sodium surface area which contact between sodium and CO{sub 2} when CO{sub 2} is injected into sodium pool in the accident situation. So, the fundamental surface reaction is experimentally studied in the range of 8 - 12cm{sup 2}. Additionally, it has been reported in recent years that CO{sub 2} Flow rate affects reactivity less significantly and CO{sub 2} flow rate is assumed that 5 SLPM (standard liter per minute) is suitable as a basis for a small leakage. The finally selected control parameters is sodium temperature and reacting surface area with constant CO{sub 2} flow rate. Na-CO{sub 2} reaction test is performed for investigating risk of potential accident which contacts with liquid sodium and CO{sub 2}. Amount of reaction is saturated as time passed because of kept a balance between production of solid phase reaction products and amount of diffusivity. These results contribute to make a

Chemical signal activation of an organocatalyst enables control over soft material formation.

Science.gov (United States)

Trausel, Fanny; Maity, Chandan; Poolman, Jos M; Kouwenberg, D S J; Versluis, Frank; van Esch, Jan H; Eelkema, Rienk

2017-10-12

Cells can react to their environment by changing the activity of enzymes in response to specific chemical signals. Artificial catalysts capable of being activated by chemical signals are rare, but of interest for creating autonomously responsive materials. We present an organocatalyst that is activated by a chemical signal, enabling temporal control over reaction rates and the formation of materials. Using self-immolative chemistry, we design a deactivated aniline organocatalyst that is activated by the chemical signal hydrogen peroxide and catalyses hydrazone formation. Upon activation of the catalyst, the rate of hydrazone formation increases 10-fold almost instantly. The responsive organocatalyst enables temporal control over the formation of gels featuring hydrazone bonds. The generic design should enable the use of a large range of triggers and organocatalysts, and appears a promising method for the introduction of signal response in materials, constituting a first step towards achieving communication between artificial chemical systems.Enzymes regulated by chemical signals are common in biology, but few such artificial catalysts exist. Here, the authors design an aniline catalyst that, when activated by a chemical trigger, catalyses formation of hydrazone-based gels, demonstrating signal response in a soft material.

Simultaneous Temperature and Velocity Diagnostic for Reacting Flows, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — A diagnostic technique is proposed for measuring temperature and velocity simultaneously in a high temperature reacting flow for aiding research in propulsion. The...

Developing Dynamic Single Page Web Applications Using Meteor : Comparing JavaScript Frameworks: Blaze and React

OpenAIRE

Yetayeh, Asabeneh

2017-01-01

This paper studies Meteor which is a JavaScript full-stack framework to develop interactive single page web applications. Meteor allows building web applications entirely in JavaScript. Meteor uses Blaze, React or AngularJS as a view layer and Node.js and MongoDB as a back-end. The main purpose of this study is to compare the performance of Blaze and React. A multi-user Blaze and React web applications with similar HTML and CSS were developed. Both applications were deployed on Heroku’s w...

Engineered Barrier System: Physical and Chemical Environment Model

International Nuclear Information System (INIS)

Jolley, D. M.; Jarek, R.; Mariner, P.

2004-01-01

The conceptual and predictive models documented in this Engineered Barrier System: Physical and Chemical Environment Model report describe the evolution of the physical and chemical conditions within the waste emplacement drifts of the repository. The modeling approaches and model output data will be used in the total system performance assessment (TSPA-LA) to assess the performance of the engineered barrier system and the waste form. These models evaluate the range of potential water compositions within the emplacement drifts, resulting from the interaction of introduced materials and minerals in dust with water seeping into the drifts and with aqueous solutions forming by deliquescence of dust (as influenced by atmospheric conditions), and from thermal-hydrological-chemical (THC) processes in the drift. These models also consider the uncertainty and variability in water chemistry inside the drift and the compositions of introduced materials within the drift. This report develops and documents a set of process- and abstraction-level models that constitute the engineered barrier system: physical and chemical environment model. Where possible, these models use information directly from other process model reports as input, which promotes integration among process models used for total system performance assessment. Specific tasks and activities of modeling the physical and chemical environment are included in the technical work plan ''Technical Work Plan for: In-Drift Geochemistry Modeling'' (BSC 2004 [DIRS 166519]). As described in the technical work plan, the development of this report is coordinated with the development of other engineered barrier system analysis model reports

Lightweight autonomous chemical identification system (LACIS)

Science.gov (United States)

Lozos, George; Lin, Hai; Burch, Timothy

2012-06-01

Smiths Detection and Intelligent Optical Systems have developed prototypes for the Lightweight Autonomous Chemical Identification System (LACIS) for the US Department of Homeland Security. LACIS is to be a handheld detection system for Chemical Warfare Agents (CWAs) and Toxic Industrial Chemicals (TICs). LACIS is designed to have a low limit of detection and rapid response time for use by emergency responders and could allow determination of areas having dangerous concentration levels and if protective garments will be required. Procedures for protection of responders from hazardous materials incidents require the use of protective equipment until such time as the hazard can be assessed. Such accurate analysis can accelerate operations and increase effectiveness. LACIS is to be an improved point detector employing novel CBRNE detection modalities that includes a militaryproven ruggedized ion mobility spectrometer (IMS) with an array of electro-resistive sensors to extend the range of chemical threats detected in a single device. It uses a novel sensor data fusion and threat classification architecture to interpret the independent sensor responses and provide robust detection at low levels in complex backgrounds with minimal false alarms. The performance of LACIS prototypes have been characterized in independent third party laboratory tests at the Battelle Memorial Institute (BMI, Columbus, OH) and indoor and outdoor field tests at the Nevada National Security Site (NNSS). LACIS prototypes will be entering operational assessment by key government emergency response groups to determine its capabilities versus requirements.

Different event-related patterns of gamma-band power in brain waves of fast- and slow-reacting subjects.

Science.gov (United States)

Jokeit, H; Makeig, S

1994-01-01

Fast- and slow-reacting subjects exhibit different patterns of gamma-band electroencephalogram (EEG) activity when responding as quickly as possible to auditory stimuli. This result appears to confirm long-standing speculations of Wundt that fast- and slow-reacting subjects produce speeded reactions in different ways and demonstrates that analysis of event-related changes in the amplitude of EEG activity recorded from the human scalp can reveal information about event-related brain processes unavailable using event-related potential measures. Time-varying spectral power in a selected (35- to 43-Hz) gamma frequency band was averaged across trials in two experimental conditions: passive listening and speeded reacting to binaural clicks, forming 40-Hz event-related spectral responses. Factor analysis of between-subject event-related spectral response differences split subjects into two near-equal groups composed of faster- and slower-reacting subjects. In faster-reacting subjects, 40-Hz power peaked near 200 ms and 400 ms poststimulus in the react condition, whereas in slower-reacting subjects, 40-Hz power just before stimulus delivery was larger in the react condition. These group differences were preserved in separate averages of relatively long and short reaction-time epochs for each group. gamma-band (20-60 Hz)-filtered event-related potential response averages did not differ between the two groups or conditions. Because of this and because gamma-band power in the auditory event-related potential is small compared with the EEG, the observed event-related spectral response features must represent gamma-band EEG activity reliably induced by, but not phase-locked to, experimental stimuli or events. PMID:8022783

Study of subgrid-scale velocity models for reacting and nonreacting flows

Science.gov (United States)

Langella, I.; Doan, N. A. K.; Swaminathan, N.; Pope, S. B.

2018-05-01

A study is conducted to identify advantages and limitations of existing large-eddy simulation (LES) closures for the subgrid-scale (SGS) kinetic energy using a database of direct numerical simulations (DNS). The analysis is conducted for both reacting and nonreacting flows, different turbulence conditions, and various filter sizes. A model, based on dissipation and diffusion of momentum (LD-D model), is proposed in this paper based on the observed behavior of four existing models. Our model shows the best overall agreements with DNS statistics. Two main investigations are conducted for both reacting and nonreacting flows: (i) an investigation on the robustness of the model constants, showing that commonly used constants lead to a severe underestimation of the SGS kinetic energy and enlightening their dependence on Reynolds number and filter size; and (ii) an investigation on the statistical behavior of the SGS closures, which suggests that the dissipation of momentum is the key parameter to be considered in such closures and that dilatation effect is important and must be captured correctly in reacting flows. Additional properties of SGS kinetic energy modeling are identified and discussed.

Chemical dosimetry system for criticality accidents.

Science.gov (United States)

Miljanić, Saveta; Ilijas, Boris

2004-01-01

Ruder Bosković Institute (RBI) criticality dosimetry system consists of a chemical dosimetry system for measuring the total (neutron + gamma) dose, and a thermoluminescent (TL) dosimetry system for a separate determination of the gamma ray component. The use of the chemical dosemeter solution chlorobenzene-ethanol-trimethylpentane (CET) is based on the radiolytic formation of hydrochloric acid, which protonates a pH indicator, thymolsulphonphthalein. The high molar absorptivity of its red form at 552 nm is responsible for a high sensitivity of the system: doses in the range 0.2-15 Gy can be measured. The dosemeter has been designed as a glass ampoule filled with the CET solution and inserted into a pen-shaped plastic holder. For dose determinations, a newly constructed optoelectronic reader has been used. The RBI team took part in the International Intercomparison of Criticality Accident Dosimetry Systems at the SILENE Reactor, Valduc, June 2002, with the CET dosimetry system. For gamma ray dose determination TLD-700 TL detectors were used. The results obtained with CET dosemeter show very good agreement with the reference values.

Effects of Fusion Tack Welds on Self-Reacting Friction Stir Welds

Science.gov (United States)

Nunes, A. C., Jr.; Pendleton, M. L.; Brooke, S. A.; Russell, C. K.

2012-01-01

In order to know whether fusion tack welds would affect the strength of self-reacting friction stir seam welds in 2195-T87 aluminum alloy, the fracture stresses of 144 tensile test coupons cut from 24 welded panels containing segments of friction stir welds were measured. Each of the panels was welded under unique processing conditions. A measure of the effect of the tack welds for each panel was devised. An analysis of the measures of the tack weld effect supported the hypothesis that fusion tack welds do not affect the strength of self-reacting friction stir welds to a 5% level of confidence.

Identification of streptococcal proteins reacting with sera from Behçet's disease and rheumatic disorders.

Science.gov (United States)

Cho, Sung Bin; Lee, Ju Hee; Ahn, Keun Jae; Cho, Suhyun; Park, Yong-Beom; Lee, Soo-Kon; Bang, Dongsik; Lee, Kwang Hoon

2010-01-01

We evaluated the reactivity of sera from Behçet's disease (BD), systemic lupus erythematosus (SLE), dermatomyositis (DM), rheumatoid arthritis (RA), and Takayasu's arteritis (TA) patients against human α-enolase and streptococcal α-enolase, and identified additional streptococcal antigens. Enzyme-linked immunosorbent assay (ELISA) and immunoblotting were performed using sera from patients with BD, SLE, DM, RA, and TA and healthy volunteers (control) against human α-enolase and streptococcal α-enolase. Immunoblot analysis and matrix-assisted laser desorption ionisation-time-of-flight mass spectrometry were used to identify and recombine other streptococcal antigens. Specific positive signals against recombinant human α-enolase were detected by IgM ELISA of serum samples from 50% of BD, 14.3% of SLE, 57.1% of DM, 42.9% of RA, and 57.1% of TA patients. Specific positive signals against streptococcal α-enolase were detected from 42.9% of BD, 14.3% of DM, and 14.3% of TA patients. No SLE and RA sera reacted against streptococcal α-enolase antigen. Streptococcal proteins reacting with sera were identified as hypothetical protein (HP) for SLE and DM patients, acid phosphatase (AP) for RA patients, and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) for TA patients. We observed that RA patients did not present serum reactivity against either HP or GAPDH though BD, SLE, DM, and TA patients did. Also, AP reacted with sera from BD, SLE, DM, RA, and TA patients.

ENGINEERED BARRIER SYSTEM: PHYSICAL AND CHEMICAL ENVIRONMENT

Energy Technology Data Exchange (ETDEWEB)

R. Jarek

2004-11-23

The purpose of this report is to describe the evolution of the physical and chemical environmental conditions within the waste emplacement drifts of the repository, including the drip shield and waste package surfaces. The abstraction model is used in the total system performance assessment for the license application (TSPA LA) to assess the performance of the engineered barrier system and the waste form. This report develops and documents a set of these abstraction-level models that describe the engineered barrier system physical and chemical environment. Where possible, these models use information directly from other reports as input, which promotes integration among process models used for TSPA-LA. Specific tasks and activities of modeling the physical and chemical environment are included in ''Technical Work Plan for: Near-Field Environment and Transport In-Drift Geochemistry Model Report Integration'' (BSC 2004 [DIRS 171156], Section 1.2.2). As described in the technical work plan, the development of this report is coordinated with the development of other engineered barrier system reports.

ENGINEERED BARRIER SYSTEM: PHYSICAL AND CHEMICAL ENVIRONMENT

Energy Technology Data Exchange (ETDEWEB)

G.H. Nieder-Westermann

2005-04-07

The purpose of this report is to describe the evolution of the physical and chemical environmental conditions within the waste emplacement drifts of the repository, including the drip shield and waste package surfaces. The abstraction model is used in the total system performance assessment for the license application (TSPA LA) to assess the performance of the engineered barrier system and the waste form. This report develops and documents a set of these abstraction-level models that describe the engineered barrier system physical and chemical environment. Where possible, these models use information directly from other reports as input, which promotes integration among process models used for TSPA-LA. Specific tasks and activities of modeling the physical and chemical environment are included in ''Technical Work Plan for: Near-Field Environment and Transport In-Drift Geochemistry Model Report Integration'' (BSC 2004 [DIRS 171156], Section 1.2.2). As described in the technical work plan, the development of this report is coordinated with the development of other engineered barrier system reports.

Engineered Barrier System: Physical and Chemical Environment Model

Energy Technology Data Exchange (ETDEWEB)

D. M. Jolley; R. Jarek; P. Mariner

2004-02-09

The conceptual and predictive models documented in this Engineered Barrier System: Physical and Chemical Environment Model report describe the evolution of the physical and chemical conditions within the waste emplacement drifts of the repository. The modeling approaches and model output data will be used in the total system performance assessment (TSPA-LA) to assess the performance of the engineered barrier system and the waste form. These models evaluate the range of potential water compositions within the emplacement drifts, resulting from the interaction of introduced materials and minerals in dust with water seeping into the drifts and with aqueous solutions forming by deliquescence of dust (as influenced by atmospheric conditions), and from thermal-hydrological-chemical (THC) processes in the drift. These models also consider the uncertainty and variability in water chemistry inside the drift and the compositions of introduced materials within the drift. This report develops and documents a set of process- and abstraction-level models that constitute the engineered barrier system: physical and chemical environment model. Where possible, these models use information directly from other process model reports as input, which promotes integration among process models used for total system performance assessment. Specific tasks and activities of modeling the physical and chemical environment are included in the technical work plan ''Technical Work Plan for: In-Drift Geochemistry Modeling'' (BSC 2004 [DIRS 166519]). As described in the technical work plan, the development of this report is coordinated with the development of other engineered barrier system analysis model reports.

A sequential-move game for enhancing safety and security cooperation within chemical clusters.

Science.gov (United States)

Pavlova, Yulia; Reniers, Genserik

2011-02-15

The present paper provides a game theoretic analysis of strategic cooperation on safety and security among chemical companies within a chemical industrial cluster. We suggest a two-stage sequential move game between adjacent chemical plants and the so-called Multi-Plant Council (MPC). The MPC is considered in the game as a leader player who makes the first move, and the individual chemical companies are the followers. The MPC's objective is to achieve full cooperation among players through establishing a subsidy system at minimum expense. The rest of the players rationally react to the subsidies proposed by the MPC and play Nash equilibrium. We show that such a case of conflict between safety and security, and social cooperation, belongs to the 'coordination with assurance' class of games, and we explore the role of cluster governance (fulfilled by the MPC) in achieving a full cooperative outcome in domino effects prevention negotiations. The paper proposes an algorithm that can be used by the MPC to develop the subsidy system. Furthermore, a stepwise plan to improve cross-company safety and security management in a chemical industrial cluster is suggested and an illustrative example is provided. Copyright © 2010 Elsevier B.V. All rights reserved.

Birefringence characteristics in sperm heads allow for the selection of reacted spermatozoa for intracytoplasmic sperm injection.

Science.gov (United States)

Gianaroli, Luca; Magli, M Cristina; Ferraretti, Anna P; Crippa, Andor; Lappi, Michela; Capitani, Serena; Baccetti, Baccio

2010-02-01

To verify clinical outcome after injection of spermatozoa that have undergone the acrosome reaction (reacted spermatozoa) vs. those still having an intact acrosome (nonreacted spermatozoa). Prospective, randomized study. Reproductive Medicine Unit, Italian Society for the Study of Reproductive Medicine, Bologna, Italy. According to a prospective randomization including 71 couples with severe male factor infertility, intracytoplasmic sperm injection (ICSI) was performed under polarized light that permitted analysis of the pattern of birefringence in the sperm head. Twenty-three patients had their oocytes injected with reacted spermatozoa, 26 patient's oocytes were injected with nonreacted spermatozoa, and in 22 patients both reacted and nonreacted spermatozoa were injected. Intracytoplasmic sperm injection was performed under polarized light to selectively inject acrosome-reacted and acrosome-nonreacted spermatozoa. Rates of fertilization, cleavage, pregnancy, implantation, and ongoing implantation. There was no effect on the fertilizing capacity and embryo development of either type of sperm, whereas the implantation rate was higher in oocytes injected with reacted spermatozoa (39.0%) vs. those injected with nonreacted spermatozoa (8.6%). The implantation rate was 24.4% in the group injected with both reacted and nonreacted spermatozoa. The delivery rate per cycle followed the same trend. Spermatozoa that have undergone the acrosome reaction seem to be more prone to supporting the development of viable ICSI embryos. Copyright 2010 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.

Construction of a Linux based chemical and biological information system.

Science.gov (United States)

Molnár, László; Vágó, István; Fehér, András

2003-01-01

A chemical and biological information system with a Web-based easy-to-use interface and corresponding databases has been developed. The constructed system incorporates all chemical, numerical and textual data related to the chemical compounds, including numerical biological screen results. Users can search the database by traditional textual/numerical and/or substructure or similarity queries through the web interface. To build our chemical database management system, we utilized existing IT components such as ORACLE or Tripos SYBYL for database management and Zope application server for the web interface. We chose Linux as the main platform, however, almost every component can be used under various operating systems.

Chemical looping reactor system design double loop circulating fluidized bed (DLCFB)

Energy Technology Data Exchange (ETDEWEB)

Bischi, Aldo

2012-05-15

Chemical looping combustion (CLC) is continuously gaining more importance among the carbon capture and storage (CCS) technologies. It is an unmixed combustion process which takes place in two steps. An effective way to realize CLC is to use two interconnected fluidized beds and a metallic powder circulating among them, acting as oxygen carrier. The metallic powder oxidizes at high temperature in one of the two reactors, the air reactor (AR). It reacts in a highly exothermic reaction with the oxygen of the injected fluidising air. Afterwards the particles are sent to the other reactor where the fuel is injected, the fuel reactor (FR). There, they transport heat and oxygen necessary for the reaction with the injected fuel to take place. At high temperatures, the particle's oxygen reacts with the fuel producing Co2 and steam, and the particles are ready to start the loop again. The overall reaction, the sum of the enthalpy changes of the oxygen carrier oxidation and reduction reactions, is the same as for the conventional combustion. Two are the key features, which make CLC promising both for costs and capture efficiency. First, the high inherent irreversibility of the conventional combustion is avoided because the energy is utilized stepwise. Second, the Co2 is intrinsically separated within the process; so there is in principle no need either of extra carbon capture devices or of expensive air separation units to produce oxygen for oxy-combustion. A lot of effort is taking place worldwide on the development of new chemical looping oxygen carrier particles, reactor systems and processes. The current work is focused on the reactor system: a new design is presented, for the construction of an atmospheric 150kWth prototype working with gaseous fuel and possibly with inexpensive oxygen carriers derived from industrial by-products or natural minerals. It consists of two circulating fluidized beds capable to operate in fast fluidization regime; this will increase the

Nonlinear Hamiltonian mechanics applied to molecular dynamics theory and computational methods for understanding molecular spectroscopy and chemical reactions

CERN Document Server

Farantos, Stavros C

2014-01-01

This brief presents numerical methods for describing and calculating invariant phase space structures, as well as solving the classical and quantum equations of motion for polyatomic molecules. Examples covered include simple model systems to realistic cases of molecules spectroscopically studied. Vibrationally excited and reacting molecules are nonlinear dynamical systems, and thus, nonlinear mechanics is the proper theory to elucidate molecular dynamics by investigating invariant structures in phase space. Intramolecular energy transfer, and the breaking and forming of a chemical bond have now found a rigorous explanation by studying phase space structures.

Second law analysis of a reacting temperature dependent viscous ...

African Journals Online (AJOL)

In this paper, entropy generation during the flow of a reacting viscous fluid through an inclined Channel with isothermal walls are investigated. The coupled energy and momentum equations were solved numerically. Previous results in literature (Adesanya et al 2006 [[17]) showed both velocity and temperature have two ...

Wave propagation in a quasi-chemical equilibrium plasma

Science.gov (United States)

Fang, T.-M.; Baum, H. R.

1975-01-01

Wave propagation in a quasi-chemical equilibrium plasma is studied. The plasma is infinite and without external fields. The chemical reactions are assumed to result from the ionization and recombination processes. When the gas is near equilibrium, the dominant role describing the evolution of a reacting plasma is played by the global conservation equations. These equations are first derived and then used to study the small amplitude wave motion for a near-equilibrium situation. Nontrivial damping effects have been obtained by including the conduction current terms.

Longitudinally Vibrating Elastic Rods with Locally and Non-Locally Reacting Viscous Dampers

Directory of Open Access Journals (Sweden)

Şefaatdin Yüksel

2005-01-01

Full Text Available Eigencharacteristics of a longitudinally vibrating elastic rod with locally and non-locally reacting damping are analyzed. The rod is considered as a continuous system and complex eigenfrequencies are determined as solution of a characteristic equation. The variation of the damping ratios with respect to damper locations and damping coefficients for the first four eigenfrequencies are obtained. It is shown that at any mode of locally or non-locally damped elastic rod, the variation of damping ratio with damper location is linearly proportional to absolute value of the mode shape of undamped system. It is seen that the increasing damping coefficient does not always increase the damping ratio and there are optimal values for the damping ratio. Optimal values for external damping coefficients of viscous dampers and locations of the dampers are presented.

Development of a Persistent Chemical Agent Simulator System (PCASS)

Science.gov (United States)

Mcginness, W. G.

1983-01-01

The development of a persistent chemical agent simulation system (PCASS) is described. This PCASS is to be used for the military training of troops to simulate actual chemical warfare. The purpose of this system is to facilitate in the determination of chemical contamination and effectiveness of decontamination for training purposes. The fluorescent tracer employed has no daylight activation, but yet is easily removed with a decontaminate solution or water and surfactants. Also employed is a time delayed color developing system. When an individual is subjected to the PCASS and does not decontaminate adequately, red blotches or red coloration will develop as a function of time and temperature. The intent of this is to simulate the delayed chemical reaction of mustard contaminates.

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

International Nuclear Information System (INIS)

Kustova, Elena V.; Kremer, Gilberto M.

2014-01-01

Highlights: • State-to-state approach for coupled vibrational relaxation and chemical reactions. • Self-consistent model for rates of non-equilibrium reactions and energy transitions. • In viscous flows mass action law is violated. • Cross coupling between reaction rates and non-equilibrium pressure in viscous flow. • Results allow implementing the state-to-state approach for viscous flow simulations. - Abstract: Viscous gas flows with vibrational relaxation and chemical reactions in the state-to-state approach are analyzed. A modified Chapman–Enskog method is used for the determination of chemical reaction and vibrational transition rates and non-equilibrium pressure. Constitutive equations depend on the thermodynamic forces: velocity divergence and chemical reaction/transition affinity. As an application, N 2 flow with vibrational relaxation across a shock wave is investigated. Two distinct processes occur behind the shock: for small values of the distance the affinity is large and vibrational relaxation is in its initial stage; for large distances the affinity is small and the chemical reaction is in its final stage. The affinity contributes more to the transition rate than the velocity divergence and the effect of these two contributions are more important for small distances from the shock front. For the non-equilibrium pressure, the term associated with the bulk viscosity increases by a small amount the hydrostatic pressure

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

Energy Technology Data Exchange (ETDEWEB)

Kustova, Elena V., E-mail: e.kustova@spbu.ru [Department of Mathematics and Mechanics, Saint Petersburg State University, 198504 Universitetskiy pr. 28, Saint Petersburg (Russian Federation); Kremer, Gilberto M., E-mail: kremer@fisica.ufpr.br [Departamento de Física, Universidade Federal do Paraná, Caixa Postal 19044, 81531-980 Curitiba (Brazil)

2014-12-05

Highlights: • State-to-state approach for coupled vibrational relaxation and chemical reactions. • Self-consistent model for rates of non-equilibrium reactions and energy transitions. • In viscous flows mass action law is violated. • Cross coupling between reaction rates and non-equilibrium pressure in viscous flow. • Results allow implementing the state-to-state approach for viscous flow simulations. - Abstract: Viscous gas flows with vibrational relaxation and chemical reactions in the state-to-state approach are analyzed. A modified Chapman–Enskog method is used for the determination of chemical reaction and vibrational transition rates and non-equilibrium pressure. Constitutive equations depend on the thermodynamic forces: velocity divergence and chemical reaction/transition affinity. As an application, N{sub 2} flow with vibrational relaxation across a shock wave is investigated. Two distinct processes occur behind the shock: for small values of the distance the affinity is large and vibrational relaxation is in its initial stage; for large distances the affinity is small and the chemical reaction is in its final stage. The affinity contributes more to the transition rate than the velocity divergence and the effect of these two contributions are more important for small distances from the shock front. For the non-equilibrium pressure, the term associated with the bulk viscosity increases by a small amount the hydrostatic pressure.

Graphene composites containing chemically bonded metal oxides

Indian Academy of Sciences (India)

the oxide layers are chemically bonded to graphene (Zhang ... sists of three glass chambers, one to contain the metal halide. (TiCl4, SiCl4 ... In this step, the metal halide reacts with the oxygen function- ... 1·0 g of FeCl3 were vigorously stirred in 30 ml of ethylene ... Reaction with water vapour results in hydrolysis of the un-.

Differing Event-Related Patterns of Gamma-Band Power in Brain Waves of Fast- and Slow-Reacting Subjects

Science.gov (United States)

1994-05-01

Wilhelm Wundt proposed that there are two types of subjects in sim- ple RT experiments: fast-reacting subjects, who respond before they fully...quickly as possible to auditory stimuli. This result appears to confirm long-standing speculations of Wundt that fast- and slow-reacting subjects...accord with the hypothesis of Wundt and others that slower ("sensorial") responders wait to fully perceive a stimulus and then react to their perception

A Finite Element Theory for Predicting the Attenuation of Extended-Reacting Liners

Science.gov (United States)

Watson, W. R.; Jones, M. G.

2009-01-01

A non-modal finite element theory for predicting the attenuation of an extended-reacting liner containing a porous facesheet and located in a no-flow duct is presented. The mathematical approach is to solve separate wave equations in the liner and duct airway and to couple these two solutions by invoking kinematic constraints at the facesheet that are consistent with a continuum theory of fluid motion. Given the liner intrinsic properties, a weak Galerkin finite element formulation with cubic polynomial basis functions is used as the basis for generating a discrete system of acoustic equations that are solved to obtain the coupled acoustic field. A state-of-the-art, asymmetric, parallel, sparse equation solver is implemented that allows tens of thousands of grid points to be analyzed. A grid refinement study is presented to show that the predicted attenuation converges. Excellent comparison of the numerically predicted attenuation to that of a mode theory (using a Haynes 25 metal foam liner) is used to validate the computational approach. Simulations are also presented for fifteen porous plate, extended-reacting liners. The construction of some of the porous plate liners suggest that they should behave as resonant liners while the construction of others suggest that they should behave as broadband attenuators. In each case the finite element theory is observed to predict the proper attenuation trend.

A review of chemical decontamination systems for nuclear facilities

International Nuclear Information System (INIS)

Chen, L.; Chamberlain, D.B.; Conner, C.; Vandegrift, G.F.

1996-01-01

With the downsizing of the Department of Energy (DOE) complex, many of its buildings and facilities will be decommissioned and dismantled. As part of this decommissioning, some form of decontamination will be required. To develop an appropriate technology for in situ chemical decontamination of equipment interiors in the decommissioning of DOE nuclear facilities, knowledge of the existing chemical decontamination methods is needed. This paper attempts to give an up-to-date review of chemical decontamination methods. This survey revealed that aqueous systems are the most widely used for the decontamination and cleaning of metal surfaces. We have subdivided the aqueous systems by types of chemical solvent: acid, alkaline permanganate, highly oxidizing, peroxide, and proprietary. Two other systems, electropolishing and foams and gels, are also described in this paper

Thermo effect of chemical reaction in irreversible electrochemical systems

International Nuclear Information System (INIS)

Tran Vinh Quy; Nguyen Tang

1989-01-01

From first law of thermodynamics the expressions of statistical calculation of 'Fundamental' and 'Thermo-chemical' thermal effects are obtained. Besides, method of calculation of thermal effect of chemical reactions in non-equilibrium electro-chemical systems is accurately discussed. (author). 7 refs

Solutions of the chemical kinetic equations for initially inhomogeneous mixtures.

Science.gov (United States)

Hilst, G. R.

1973-01-01

Following the recent discussions by O'Brien (1971) and Donaldson and Hilst (1972) of the effects of inhomogeneous mixing and turbulent diffusion on simple chemical reaction rates, the present report provides a more extensive analysis of when inhomogeneous mixing has a significant effect on chemical reaction rates. The analysis is then extended to the development of an approximate chemical sub-model which provides much improved predictions of chemical reaction rates over a wide range of inhomogeneities and pathological distributions of the concentrations of the reacting chemical species. In particular, the development of an approximate representation of the third-order correlations of the joint concentration fluctuations permits closure of the chemical sub-model at the level of the second-order moments of these fluctuations and the mean concentrations.

Conservation-dissipation structure of chemical reaction systems.

Science.gov (United States)

Yong, Wen-An

2012-12-01

In this Brief Report, we show that balanced chemical reaction systems governed by the law of mass action have an elegant conservation-dissipation structure. From this structure a number of important conclusions can be easily deduced. In particular, with the help of this structure we can rigorously justify the classical partial equilibrium approximation in chemical kinetics.

Stochastic thermodynamics and entropy production of chemical reaction systems

Science.gov (United States)

Tomé, Tânia; de Oliveira, Mário J.

2018-06-01

We investigate the nonequilibrium stationary states of systems consisting of chemical reactions among molecules of several chemical species. To this end, we introduce and develop a stochastic formulation of nonequilibrium thermodynamics of chemical reaction systems based on a master equation defined on the space of microscopic chemical states and on appropriate definitions of entropy and entropy production. The system is in contact with a heat reservoir and is placed out of equilibrium by the contact with particle reservoirs. In our approach, the fluxes of various types, such as the heat and particle fluxes, play a fundamental role in characterizing the nonequilibrium chemical state. We show that the rate of entropy production in the stationary nonequilibrium state is a bilinear form in the affinities and the fluxes of reaction, which are expressed in terms of rate constants and transition rates, respectively. We also show how the description in terms of microscopic states can be reduced to a description in terms of the numbers of particles of each species, from which follows the chemical master equation. As an example, we calculate the rate of entropy production of the first and second Schlögl reaction models.

Multi-scenario modelling of uncertainty in stochastic chemical systems

International Nuclear Information System (INIS)

Evans, R. David; Ricardez-Sandoval, Luis A.

2014-01-01

Uncertainty analysis has not been well studied at the molecular scale, despite extensive knowledge of uncertainty in macroscale systems. The ability to predict the effect of uncertainty allows for robust control of small scale systems such as nanoreactors, surface reactions, and gene toggle switches. However, it is difficult to model uncertainty in such chemical systems as they are stochastic in nature, and require a large computational cost. To address this issue, a new model of uncertainty propagation in stochastic chemical systems, based on the Chemical Master Equation, is proposed in the present study. The uncertain solution is approximated by a composite state comprised of the averaged effect of samples from the uncertain parameter distributions. This model is then used to study the effect of uncertainty on an isomerization system and a two gene regulation network called a repressilator. The results of this model show that uncertainty in stochastic systems is dependent on both the uncertain distribution, and the system under investigation. -- Highlights: •A method to model uncertainty on stochastic systems was developed. •The method is based on the Chemical Master Equation. •Uncertainty in an isomerization reaction and a gene regulation network was modelled. •Effects were significant and dependent on the uncertain input and reaction system. •The model was computationally more efficient than Kinetic Monte Carlo

Chemical composition of hydrothermal ores from Mid-Okinawa trough and Suiyo Seamount determined by neutron activation analysis

International Nuclear Information System (INIS)

Noguchi, Takuroh; Taira, Naoto; Oomori, Tamotsu; Taira, Hatsuo; Tanahara, Akira; Takada, Jitsuya

2007-01-01

Neutron activation analysis of 13 hydrothermal ore samples (70 subsamples) collected from the Mid-Okinawa Trough and Suiyo Seamount revealed higher contents of precious metal such as Au and Ag, and those of As, Sb, Ga, and Hg than those from mid-ocean ridge hydrothermal systems. In addition, the Mid-Okinawa Trough samples were richer in Ag and Sb than those from the Suiyo Seamount. The geochemical differences among these hydrothermal ore deposits are regarded as reflecting both differences in the chemical composition of the hosted magma of hydrothermal system and the abundance of sediments that is reacted with hydrothermal fluids. (author)

Systems approach to chemical spill response information needs

Energy Technology Data Exchange (ETDEWEB)

Parnarouskis, M.C.; Flessner, M.F.; Potts, R.G.

1980-01-01

The Chemical Hazards Response Information System (CHRIS) has been specifically designed to meet the emergency needs of US Coast Guard field personnel, currently providing them with information on 900 hazardous chemicals, with methods of predicting hazards resulting from accidental discharges, and with procedures for selecting and implementing response to accident discharges. The major components of CHRIS and the computerized hazard assessment models within the Hazard Assessment Computer System are described in detail.

[A surface reacted layer study of titanium-zirconium alloy after dental casting].

Science.gov (United States)

Zhang, Y; Guo, T; Li, Z; Li, C

2000-10-01

To investigate the influence of the mold temperature on the surface reacted layer of Ti-Zr alloy castings. Ti-Zr alloy was casted into a mold which was made of a zircon (ZrO2.SiO2) for inner coating and a phosphate-bonded material for outer investing with a casting machine (China) designed as vacuum, pressure and centrifuge. At three mold temperatures (room temperature, 300 degrees C, 600 degrees C) the Ti-Zr alloy was casted separately. The surface roughness of the castings was calculated by instrument of smooth finish (China). From the surface to the inner part the Knoop hardness and thickness in reacted layer of Ti-Zr alloy casting was measured. The structure of the surface reacted layer was analysed by SEM. Elemental analyses of the interfacial zone of the casting was made by element line scanning observation. The surface roughness of the castings was increased significantly with the mold temperature increasing. At a higher mold temperature the Knoop hardness of the reactive layer was increased. At the three mold temperature the outmost surface was very hard, and microhardness data decreased rapidly where they reached constant values. The thickness was about 85 microns for castings at room temperature and 300 degrees C, 105 microns for castings at 600 degrees C. From the SEM micrograph of the Ti-Zr alloy casting, the surface reacted layer could be divided into three different layers. The first layer was called non-structure layer, which thickness was about 10 microns for room temperature group, 20 microns for 300 degrees C and 25 microns for 600 degrees C. The second layer was characterized by coarse-grained acicular crystal, which thickness was about 50 microns for three mold temperatures. The third layer was Ti-Zr alloy. The element line scanning showed non-structure layer with higher level of element of O, Al, Si and Zr, The higher the mold temperature during casting, the deeper the Si permeating and in the second layer the element Si could also be found

Experimental thermodynamics experimental thermodynamics of non-reacting fluids

CERN Document Server

Neindre, B Le

2013-01-01

Experimental Thermodynamics, Volume II: Experimental Thermodynamics of Non-reacting Fluids focuses on experimental methods and procedures in the study of thermophysical properties of fluids. The selection first offers information on methods used in measuring thermodynamic properties and tests, including physical quantities and symbols for physical quantities, thermodynamic definitions, and definition of activities and related quantities. The text also describes reference materials for thermometric fixed points, temperature measurement under pressures, and pressure measurements. The publicatio

''A Parallel Adaptive Simulation Tool for Two Phase Steady State Reacting Flows in Industrial Boilers and Furnaces''; FINAL

International Nuclear Information System (INIS)

Michael J. Bockelie

2002-01-01

This DOE SBIR Phase II final report summarizes research that has been performed to develop a parallel adaptive tool for modeling steady, two phase turbulent reacting flow. The target applications for the new tool are full scale, fossil-fuel fired boilers and furnaces such as those used in the electric utility industry, chemical process industry and mineral/metal process industry. The type of analyses to be performed on these systems are engineering calculations to evaluate the impact on overall furnace performance due to operational, process or equipment changes. To develop a Computational Fluid Dynamics (CFD) model of an industrial scale furnace requires a carefully designed grid that will capture all of the large and small scale features of the flowfield. Industrial systems are quite large, usually measured in tens of feet, but contain numerous burners, air injection ports, flames and localized behavior with dimensions that are measured in inches or fractions of inches. To create an accurate computational model of such systems requires capturing length scales within the flow field that span several orders of magnitude. In addition, to create an industrially useful model, the grid can not contain too many grid points - the model must be able to execute on an inexpensive desktop PC in a matter of days. An adaptive mesh provides a convenient means to create a grid that can capture both fine flow field detail within a very large domain with a ''reasonable'' number of grid points. However, the use of an adaptive mesh requires the development of a new flow solver. To create the new simulation tool, we have combined existing reacting CFD modeling software with new software based on emerging block structured Adaptive Mesh Refinement (AMR) technologies developed at Lawrence Berkeley National Laboratory (LBNL). Specifically, we combined: -physical models, modeling expertise, and software from existing combustion simulation codes used by Reaction Engineering International

Chemical reaction networks as a model to describe UVC- and radiolytically-induced reactions of simple compounds.

Science.gov (United States)

Dondi, Daniele; Merli, Daniele; Albini, Angelo; Zeffiro, Alberto; Serpone, Nick

2012-05-01

When a chemical system is submitted to high energy sources (UV, ionizing radiation, plasma sparks, etc.), as is expected to be the case of prebiotic chemistry studies, a plethora of reactive intermediates could form. If oxygen is present in excess, carbon dioxide and water are the major products. More interesting is the case of reducing conditions where synthetic pathways are also possible. This article examines the theoretical modeling of such systems with random-generated chemical networks. Four types of random-generated chemical networks were considered that originated from a combination of two connection topologies (viz., Poisson and scale-free) with reversible and irreversible chemical reactions. The results were analyzed taking into account the number of the most abundant products required for reaching 50% of the total number of moles of compounds at equilibrium, as this may be related to an actual problem of complex mixture analysis. The model accounts for multi-component reaction systems with no a priori knowledge of reacting species and the intermediates involved if system components are sufficiently interconnected. The approach taken is relevant to an earlier study on reactions that may have occurred in prebiotic systems where only a few compounds were detected. A validation of the model was attained on the basis of results of UVC and radiolytic reactions of prebiotic mixtures of low molecular weight compounds likely present on the primeval Earth.

How Did the Asian Stock Markets React to Bank Mergera after the 1997 Financial Crisis?

OpenAIRE

Meslier-Crouzille , Céline; Lepetit , Laetitia; Bautista , Carlos C.

2008-01-01

International audience; The objective of this paper is to empirically assess the stock market reaction to the announcement of bank mergers and acquisitions (M&As) in eight East Asian countries over the 1997-2003 period. M&As are classified according to the status of entity, the time period of the deal and the maturity of the banking system. A bivariate GARCH model is used to estimate abnormal returns taking beta conditional variability into account. We find that the market reacted negatively ...

Does the StartReact Effect Apply to First-Trial Reactive Movements?

Directory of Open Access Journals (Sweden)

Katrin Sutter

Full Text Available StartReact is the acceleration of reaction time by a startling acoustic stimulus (SAS. The SAS is thought to release a pre-prepared motor program. Here, we investigated whether the StartReact effect is applicable to the very first trial in a series of repeated unpractised single-joint movements.Twenty healthy young subjects were instructed to perform a rapid ankle dorsiflexion movement in response to an imperative stimulus. Participants were divided in two groups of ten. Both groups performed 17 trials. In one group a SAS (116 dB was given in the first trial, whereas the other group received a non-startling sound (70 dB as the first imperative stimulus. In the remaining 16 trials, the SAS was given as the imperative stimulus in 25% of the trials in both groups. The same measurement was repeated one week later, but with the first-trial stimuli counterbalanced between groups.When a SAS was given in the very first trial, participants had significantly shorter onset latencies compared to first-trial responses to a non-startling stimulus. Succeeding trials were significantly faster compared to the first trial, both for trials with and without a SAS. However, the difference between the first and succeeding trials was significantly larger for responses to a non-startling stimulus compared to responses triggered by a SAS. SAS-induced acceleration in the first trial of the second session was similar to that in succeeding trials of session 1.The present results confirm that the StartReact phenomenon also applies to movements that have not yet been practiced in the experimental context. The excessive SAS-induced acceleration in the very first trial may be due to the absence of integration of novel context-specific information with the existing motor memory for movement execution. Our findings demonstrate that StartReact enables a rapid release of motor programs in the very first trial also without previous practice, which might provide a behavioural

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

Sensitive Diagnostics for Chemically Reacting Flows

KAUST Repository

Farooq, Aamir

2015-01-01

This talk will feature latest diagnostic developments for sensitive detection of gas temperature and important combustion species. Advanced optical strategies, such as intrapulse chirping, wavelength modulation, and cavity ringdown are employed.

Numerical Simulation of Chemically Reacting Flows

Science.gov (United States)

2015-09-03

flam in three spa ructured gri olves couple ed nature pr described in e LRR3D a Jacobian (no e rate of Ne t way, so th may be nonz local connec ion...the M formulation. omputationa prediction, mostly over mportant ad taggered gri . With all t pproach th 2012, the M ncluding fla mes with ad ate

Sensitive Diagnostics for Chemically Reacting Flows

KAUST Repository

Farooq, Aamir

2015-11-02

This talk will feature latest diagnostic developments for sensitive detection of gas temperature and important combustion species. Advanced optical strategies, such as intrapulse chirping, wavelength modulation, and cavity ringdown are employed.

[Prospects in getting accordance between chemical analytic control means and medical technical requirements to safety system concerning chemical weapons destruction].

Science.gov (United States)

Rembovskiĭ, V R; Mogilenkova, L A; Savel'eva, E I

2005-01-01

The major unit monitoring chemical weapons destruction objects is a system of chemical analyticcontrol over the technologic process procedures and possibility of environment and workplace pollution withtoxicchemicals and their destruction products. At the same time, physical and chemical control means meet sanitary and hygienic requirements incompletely. To provide efficient control, internationally recognized approaches should be adapted to features of Russian system monitoring pollution of chemical weapons destruction objects with toxic chemicals.

Physical and chemical trigger factors in environmental intolerance.

Science.gov (United States)

Claeson, Anna-Sara; Palmquist, Eva; Nordin, Steven

2018-04-01

Individuals with environmental intolerance (EI) react to exposure from different environmental sources at levels tolerated by most people and that are below established toxicological and hazardous thresholds. The main aim of this study was to determine the prevalence of attributing symptoms to chemical and physical sources in the environment among individuals with different forms of self-reported EI and in referents. Cross-sectional data from a population-based study, the Västerbotten Environmental Health Study (n = 3406), were used and individuals with self-reported EI to chemicals, buildings, electromagnetic fields and sounds as well as a group with multiple EIs were identified. The Environmental-Symptom Attribution Scale was used to quantify degree to which health symptoms are attributed to 40 specific environmental exposures and sources, with subscales referring to the four types of EI. All EI groups, except the group with building related intolerance (BRI), reported more symptoms from the expected sources compared to the referents. In addition, individuals with chemical and sound intolerance reported symptoms from building related trigger factors, and individuals with electromagnetic hypersensitivity reported symptoms from chemical trigger factors. The study suggests that individuals with BRI react to fewer and more specific trigger factors than do individuals with other EIs, and that it is important to ask about different sources since three of the EI groups attribute their symptoms to a wide variety of sources in addition to the sources to which their EI implicates. Copyright © 2018 Elsevier GmbH. All rights reserved.

Chemical repair of trypsin-histidinyl radical

International Nuclear Information System (INIS)

Jovanovic, S.V.; Ruvarac, I.; Jankovic, I.; Josimovic, L.

1991-01-01

Oxyl radicals, such as hydroxyl, alkoxyl and peroxyl, react with biomolecules to produce bioradicals. Unless chemically repaired by suitable antioxidants, these bioradicals form stable products. This leads to loss of biological function of parent biomolecules with deleterious biological results, such as mutagenesis and cancer. Consequently, the understanding of the mechanisms of oxyl radical damage to biomolecules and chemical repair of such damage is crucial for the development of strategies for anticarcinogenesis and radioprotection. In this study the chemical repair of the histidinyl radical generated upon the trichloromethylperoxyl radical reaction with trypsin vas investigated by gamma radiolysis. The trypsin histidinyl radical is a resonance-stabilized heterocyclic free radical which was found to be unreactive with oxygen. The efficacy of the chemical repair of the trypsin-histidinyl radical by endogenous antioxidants which are electron donors (e.g. 5-hydroxytryptophan, uric acid) is compared to that of antioxidants which are H-atom donors (e. g. glutathione). 9 refs., 2 figs., 1 tab

TPR system: a powerful technique to monitor carbon nanotube formation during chemical vapour deposition; Sistema RTP: uma tecnica poderosa para o monitoramento da formacao de nanotubos de carbono durante o processo por deposicao de vapor quimico

Energy Technology Data Exchange (ETDEWEB)

Tristao, Juliana Cristina; Moura, Flavia Cristina Camilo; Lago, Rochel Montero, E-mail: rochel@ufmg.b [Universidade Federal de Minas Gerais (DQ/UFMG), Belo Horizonte, MG (Brazil). Dept. de Quimica; Sapag, Karim [Universidade Nacional de San Luis (Argentina). Lab. de Ciencias de Superficies y Medios Porosos

2010-07-01

In this work, a TPR (Temperature Programmed Reduction) system is used as a powerful tool to monitor carbon nanotubes production during CVD (Chemical Vapour Deposition), The experiments were carried out using catalyst precursors based on Fe-Mo supported on Al{sub 2}O{sub 3} and methane as carbon source. As methane reacts on the Fe metal surface, carbon is deposited and H2 is produced. TPR is very sensitive to the presence of H2 and affords information on the temperature where catalyst is active to form different forms of carbon, the reaction kinetics, the catalyst deactivation and carbon yields. (author)

Chemical Detection Architecture for a Subway System [video

OpenAIRE

Ignacio, Joselito; Center for Homeland Defense and Security Naval Postgraduate School

2014-01-01

This proposed system process aims to improve subway safety through better enabling the rapid detection and response to a chemical release in a subway system. The process is designed to be location-independent and generalized to most subway systems despite each system's unique characteristics.

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.

Chemical Reactions in Turbulent Mixing Flows

Science.gov (United States)

1992-07-01

Chemically-Reacting, Gas-Phase Turbulent Jets (Gilbrech 1991), that explored Reynolds number effects on turbulent flame length and the influence of...and asymptotes to a constant value beyond the flame tip. The main result of the work is that the flame length , as estimated from the temperature...8217. Specifically, the normalized flame length Lf/d* displays a linear dependence on the stoichiometric mixture ratio 0, with a slope that decreases from Re "• 1.0

Design and synthesis of reactive separation systems

Energy Technology Data Exchange (ETDEWEB)

Doherty, M.F.

1992-01-01

During the last decade there has been a rapid upturn in interest in reactive distillation. The chemical process industry recognizes the favorable economics of carrying out reaction simultaneously with distillation for certain classes of reacting systems, and many new processes have been built based on this technology. Interest is also increasing by academics and software vendors. Systematic design methods for reactive distillation systems have only recently begun to emerge. In this report we survey the available design techniques and point out the contributions made by our group at the University of Massachusetts.

Microfabricated Gas Phase Chemical Analysis Systems

International Nuclear Information System (INIS)

FRYE-MASON, GREGORY CHARLES; HELLER, EDWIN J.; HIETALA, VINCENT M.; KOTTENSTETTE, RICHARD; LEWIS, PATRICK R.; MANGINELL, RONALD P.; MATZKE, CAROLYN M.; WONG, CHUNGNIN C.

1999-01-01

A portable, autonomous, hand-held chemical laboratory ((micro)ChemLab(trademark)) is being developed for trace detection (ppb) of chemical warfare (CW) agents and explosives in real-world environments containing high concentrations of interfering compounds. Microfabrication is utilized to provide miniature, low-power components that are characterized by rapid, sensitive and selective response. Sensitivity and selectivity are enhanced using two parallel analysis channels, each containing the sequential connection of a front-end sample collector/concentrator, a gas chromatographic (GC) separator, and a surface acoustic wave (SAW) detector. Component design and fabrication and system performance are described

Introducing DAE Systems in Undergraduate and Graduate Chemical Engineering Curriculum

Science.gov (United States)

Mandela, Ravi Kumar; Sridhar, L. N.; Rengaswamy, Raghunathan

2010-01-01

Models play an important role in understanding chemical engineering systems. While differential equation models are taught in standard modeling and control courses, Differential Algebraic Equation (DAE) system models are not usually introduced. These models appear naturally in several chemical engineering problems. In this paper, the introduction…

Rule-Based Multidisciplinary Tool for Unsteady Reacting Real-Fluid Flows, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — A design and analysis computational tool is proposed for simulating unsteady reacting flows in combustor devices used in reusable launch vehicles. Key aspects...

Chemical Cell Lysis System Applicable to Lab-on-a-Disc.

Science.gov (United States)

Lim, Dayeseul; Yoo, Jae Chern

2017-09-01

The design and fabrication of a heating system has been a significant challenge in implementing chemical lysis on a lab-on-a-disc (LOD). The proposed system contains a sample inlet, phase change material (PCM) array, heating chamber, and valve in a single disc, providing cost-effective, rapid, and fully automated chemical cell lysis. Compared to the conventional cell lysis system, our cell lysis system has many advantages, such as a compact structure that is easily integrated into the LOD and reduced processing time and labor. The experiments are conducted with Salmonella typhimurium strains to demonstrate the performance. The experimental results show that the proposed approach is greatly effective in realizing a chemical cell lysis system on an LOD with higher throughput in terms of purity and yield of DNA.

Non-equilibrium reaction rates in chemical kinetic equations

Science.gov (United States)

Gorbachev, Yuriy

2018-05-01

Within the recently proposed asymptotic method for solving the Boltzmann equation for chemically reacting gas mixture, the chemical kinetic equations has been derived. Corresponding one-temperature non-equilibrium reaction rates are expressed in terms of specific heat capacities of the species participate in the chemical reactions, bracket integrals connected with the internal energy transfer in inelastic non-reactive collisions and energy transfer coefficients. Reactions of dissociation/recombination of homonuclear and heteronuclear diatomic molecules are considered. It is shown that all reaction rates are the complex functions of the species densities, similarly to the unimolecular reaction rates. For determining the rate coefficients it is recommended to tabulate corresponding bracket integrals, additionally to the equilibrium rate constants. Correlation of the obtained results with the irreversible thermodynamics is established.

Nanomotor dynamics in a chemically oscillating medium

Energy Technology Data Exchange (ETDEWEB)

Robertson, Bryan, E-mail: bryan.robertson@mail.utoronto.ca; Kapral, Raymond, E-mail: rkapral@chem.utoronto.ca [Chemical Physics Theory Group, Department of Chemistry, University of Toronto, Toronto, Ontario M5S 3H6 (Canada)

2015-04-21

Synthetic nanomotors powered by chemical reactions have potential uses as cargo transport vehicles in both in vivo and in vitro applications. In many situations, motors will have to operate in out-of-equilibrium complex chemically reacting media, which supply fuel to the motors and remove the products they produce. Using molecular simulation and mean-field theory, this paper describes some of the new features that arise when a chemically powered nanomotor, operating through a diffusiophoretic mechanism, moves in an environment that supports an oscillatory chemical reaction network. It is shown how oscillations in the concentrations in chemical species in the environment give rise to oscillatory motor dynamics. More importantly, since the catalytic reactions on the motor that are responsible for its propulsion couple to the bulk phase reaction network, the motor can change its local environment. This process can give rise to distinctive spatiotemporal structures in reaction-diffusion media that occur as a result of active motor motion. Such locally induced nonequilibrium structure will play an important role in applications that involve motor dynamics in complex chemical media.

Nanomotor dynamics in a chemically oscillating medium

International Nuclear Information System (INIS)

Robertson, Bryan; Kapral, Raymond

2015-01-01

Synthetic nanomotors powered by chemical reactions have potential uses as cargo transport vehicles in both in vivo and in vitro applications. In many situations, motors will have to operate in out-of-equilibrium complex chemically reacting media, which supply fuel to the motors and remove the products they produce. Using molecular simulation and mean-field theory, this paper describes some of the new features that arise when a chemically powered nanomotor, operating through a diffusiophoretic mechanism, moves in an environment that supports an oscillatory chemical reaction network. It is shown how oscillations in the concentrations in chemical species in the environment give rise to oscillatory motor dynamics. More importantly, since the catalytic reactions on the motor that are responsible for its propulsion couple to the bulk phase reaction network, the motor can change its local environment. This process can give rise to distinctive spatiotemporal structures in reaction-diffusion media that occur as a result of active motor motion. Such locally induced nonequilibrium structure will play an important role in applications that involve motor dynamics in complex chemical media

Double shock experiments and reactive flow modeling on LX-17 to understand the reacted equation of state

International Nuclear Information System (INIS)

Vandersall, Kevin S; Garcia, Frank; Fried, Laurence E; Tarver, Craig M

2014-01-01

Experimental data from measurements of the reacted state of an energetic material are desired to incorporate reacted states in modeling by computer codes. In a case such as LX-17 (92.5% TATB and 7.5% Kel-F by weight), where the time dependent kinetics of reaction is still not fully understood and the reacted state may evolve over time, this information becomes even more vital. Experiments were performed to measure the reacted state of LX-17 using a double shock method involving the use of two flyer materials (with known properties) mounted on the projectile that send an initial shock through the material close to or above the Chapman-Jouguet (CJ) state followed by a second shock at a higher magnitude into the detonated material. By measuring the parameters of the first and second shock waves, information on the reacted state can be obtained. The LX-17 detonation reaction zone profiles plus the arrival times and amplitudes of reflected shocks in LX-17 detonation reaction products were measured using Photonic Doppler Velocimetry (PDV) probes and an aluminum foil coated LiF window. A discussion of this work will include the experimental parameters, velocimetry profiles, data interpretation, reactive CHEETAH and Ignition and Growth modeling, as well as detail on possible future experiments.

The Theory of Thermodynamics for Chemical Reactions in Dispersed Heterogeneous Systems

Science.gov (United States)

Yongqiang; Baojiao; Jianfeng

1997-07-01

In this paper, the expressions of Gibbs energy change, enthalpy change, entropy change, and equilibrium constant for chemical reactions in dispersed heterogeneous systems are derived using classical thermodynamics theory. The thermodynamical relations for the same reaction system between the dispersed and the block state are also derived. The effects of degree of dispersion on thermodynamical properties, reaction directions, and chemical equilibria are discussed. The results show that the present equation of thermodynamics for chemical reactions is only a special case of the above-mentioned formulas and that the effect of the dispersity of a heterogeneous system on the chemical reaction obeys the Le Chatelier principle of movement of equilibria.

On microscopic simulations of systems with model chemical reactions

International Nuclear Information System (INIS)

Gorecki, J.; Gorecka, J.N.

1998-01-01

Large scale computer simulations of model chemical systems play the role of idealized experiments in which theories may be tested. In this paper we present two applications of microscopic simulations based on the reactive hard sphere model. We investigate the influence of internal fluctuations on an oscillating chemical system and observe how they modify the phase portrait of it. Another application, we consider, is concerned with the propagation of a chemical wave front associated with a thermally activated reaction. It is shown that the nonequilibrium effects increase the front velocity if compared with the velocity of the front generated by a nonactivated process characterized by the same rate constant. (author)

Chemical interaction of B4C, B, and C with Mo/Si layered structures

International Nuclear Information System (INIS)

Rooij-Lohmann, V. I. T. A. de; Veldhuizen, L. W.; Zoethout, E.; Yakshin, A. E.; Kruijs, R. W. E. van de; Thijsse, B. J.; Gorgoi, M.; Schaefers, F.; Bijkerk, F.

2010-01-01

To enhance the thermal stability, B 4 C diffusion barrier layers are often added to Mo/Si multilayer structures for extreme ultraviolet optics. Knowledge about the chemical interaction between B 4 C and Mo or Si, however is largely lacking. Therefore, the chemical processes during annealing up to 600 deg. C of a Mo/B 4 C/Si layered structure have been investigated in situ with hard x-ray photoelectron spectroscopy and ex situ with depth profiling x-ray photoelectron spectroscopy. Mo/B/Si and Mo/C/Si structures have also been analyzed as reference systems. The chemical processes in these systems have been identified, with two stages being distinguished. In the first stage, B and C diffuse and react predominantly with Mo. MoSi x forms in the second stage. If the diffusion barrier consists of C or B 4 C, a compound forms that is stable up to the maximum probed temperature and annealing time. We suggest that the diffusion barrier function of B 4 C interlayers as reported in literature can be caused by the stability of the formed compound, rather than by the stability of B 4 C itself.

Ultrasound-mediated drug delivery by gas bubbles generated from a chemical reaction.

Science.gov (United States)

Lee, Sungmun; Al-Kaabi, Leena; Mawart, Aurélie; Khandoker, Ahsan; Alsafar, Habiba; Jelinek, Herbert F; Khalaf, Kinda; Park, Ji-Ho; Kim, Yeu-Chun

2018-02-01

Highly echogenic and ultrasound-responsive microbubbles such as nitrogen and perfluorocarbons have been exploited as ultrasound-mediated drug carriers. Here, we propose an innovative method for drug delivery using microbubbles generated from a chemical reaction. In a novel drug delivery system, luminol encapsulated in folate-conjugated bovine serum albumin nanoparticles (Fol-BSAN) can generate nitrogen gas (N 2 ) by chemical reaction when it reacts with hydrogen peroxide (H 2 O 2 ), one of reactive oxygen species (ROS). ROS plays an important role in the initiation and progression of cancer and elevated ROS have been observed in cancer cells both in vitro and in vivo. High-intensity focussed ultrasound (HIFU) is used to burst the N 2 microbubbles, causing site-specific delivery of anticancer drugs such as methotrexate. In this research, the drug delivery system was optimised by using water-soluble luminol and Mobil Composition of Matter-41 (MCM-41), a mesoporous material, so that the delivery system was sensitive to micromolar concentrations of H 2 O 2 . HIFU increased the drug release from Fol-BSAN by 52.9 ± 2.9% in 10 minutes. The cytotoxicity of methotrexate was enhanced when methotrexate is delivered to MDA-MB-231, a metastatic human breast cancer cell line, using Fol-BSAN with HIFU. We anticipate numerous applications of chemically generated microbubbles for ultrasound-mediated drug delivery.

Chemical compatibility study of lithium titanate with Indian reduced activation ferritic martensitic steel

International Nuclear Information System (INIS)

Sonak, Sagar; Jain, Uttam; Haldar, Rumu; Kumar, Sanjay

2015-01-01

Highlights: • Chemical compatibility between Li_2TiO_3 and Indian RAFM steel has been studied at ITER operating temperature. • The lithium titanate chemically reacted with ferritic martensitic steel to form a brittle and non-adherent oxide layer. • The layer grew in a parabolic manner as a function of heating time. • Diffusion of oxygen (from Li_2TiO_3) appears to be controlling the oxide layer. - Abstract: Chemical compatibility between lithium titanate and Indian reduced activation ferritic-martensitic steel (In-RAFMS) was studied for the first time under ITER operating temperature. Lithium titanate required for the study was synthesized in-house. Coupons of In-RAFMS were packed inside lithium titanate powder and heated at 550 °C up to 900 h under inert argon atmosphere. The lithium titanate chemically reacted with ferritic martensitic steel to form a brittle and non-adherent oxide layer. The layer grew in a parabolic manner as a function of heating time. Microstructural and phase evolution of this oxide layer was studied using XRD, SEM and EPMA. Iron and chromium enriched zones were found within the oxide layer. Diffusion of oxygen (from Li_2TiO_3) appears to be controlling the oxide layer.

Numerical simulation of low Mach number reacting flows

International Nuclear Information System (INIS)

Bell, J B; Aspden, A J; Day, M S; Lijewski, M J

2007-01-01

Using examples from active research areas in combustion and astrophysics, we demonstrate a computationally efficient numerical approach for simulating multiscale low Mach number reacting flows. The method enables simulations that incorporate an unprecedented range of temporal and spatial scales, while at the same time, allows an extremely high degree of reaction fidelity. Sample applications demonstrate the efficiency of the approach with respect to a traditional time-explicit integration method, and the utility of the methodology for studying the interaction of turbulence with terrestrial and astrophysical flame structures

REAC/TS Radiation Accident Registry: An Overview

Energy Technology Data Exchange (ETDEWEB)

Doran M. Christensen, DO, REAC/TS Associate Director and Staff Physician Becky Murdock, REAC/TS Registry and Health Physics Technician

2012-12-12

Over the past four years, REAC/TS has presented a number of case reports from its Radiation Accident Registry. Victims of radiological or nuclear incidents must meet certain dose criteria for an incident to be categorized as an “accident” and be included in the registry. Although the greatest numbers of “accidents” in the United States that have been entered into the registry involve radiation devices, the greater percentage of serious accidents have involved sealed sources of one kind or another. But if one looks at the kinds of accident scenarios that have resulted in extreme consequence, i.e., death, the greater share of deaths has occurred in medical settings.

Non-equilibrium Quasi-Chemical Nucleation Model

Science.gov (United States)

Gorbachev, Yuriy E.

2018-04-01

Quasi-chemical model, which is widely used for nucleation description, is revised on the basis of recent results in studying of non-equilibrium effects in reacting gas mixtures (Kolesnichenko and Gorbachev in Appl Math Model 34:3778-3790, 2010; Shock Waves 23:635-648, 2013; Shock Waves 27:333-374, 2017). Non-equilibrium effects in chemical reactions are caused by the chemical reactions themselves and therefore these contributions should be taken into account in the corresponding expressions for reaction rates. Corrections to quasi-equilibrium reaction rates are of two types: (a) spatially homogeneous (caused by physical-chemical processes) and (b) spatially inhomogeneous (caused by gas expansion/compression processes and proportional to the velocity divergency). Both of these processes play an important role during the nucleation and are included into the proposed model. The method developed for solving the generalized Boltzmann equation for chemically reactive gases is applied for solving the set of equations of the revised quasi-chemical model. It is shown that non-equilibrium processes lead to essential deviation of the quasi-stationary distribution and therefore the nucleation rate from its traditional form.

Features in chemical kinetics. I. Signatures of self-emerging dimensional reduction from a general format of the evolution law.

Science.gov (United States)

Nicolini, Paolo; Frezzato, Diego

2013-06-21

Simplification of chemical kinetics description through dimensional reduction is particularly important to achieve an accurate numerical treatment of complex reacting systems, especially when stiff kinetics are considered and a comprehensive picture of the evolving system is required. To this aim several tools have been proposed in the past decades, such as sensitivity analysis, lumping approaches, and exploitation of time scales separation. In addition, there are methods based on the existence of the so-called slow manifolds, which are hyper-surfaces of lower dimension than the one of the whole phase-space and in whose neighborhood the slow evolution occurs after an initial fast transient. On the other hand, all tools contain to some extent a degree of subjectivity which seems to be irremovable. With reference to macroscopic and spatially homogeneous reacting systems under isothermal conditions, in this work we shall adopt a phenomenological approach to let self-emerge the dimensional reduction from the mathematical structure of the evolution law. By transforming the original system of polynomial differential equations, which describes the chemical evolution, into a universal quadratic format, and making a direct inspection of the high-order time-derivatives of the new dynamic variables, we then formulate a conjecture which leads to the concept of an "attractiveness" region in the phase-space where a well-defined state-dependent rate function ω has the simple evolution ω[over dot]=-ω(2) along any trajectory up to the stationary state. This constitutes, by itself, a drastic dimensional reduction from a system of N-dimensional equations (being N the number of chemical species) to a one-dimensional and universal evolution law for such a characteristic rate. Step-by-step numerical inspections on model kinetic schemes are presented. In the companion paper [P. Nicolini and D. Frezzato, J. Chem. Phys. 138, 234102 (2013)] this outcome will be naturally related to the

30 CFR 75.1101-15 - Construction of dry powder chemical systems.

Science.gov (United States)

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Construction of dry powder chemical systems. 75.1101-15 Section 75.1101-15 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR...-15 Construction of dry powder chemical systems. (a) Each self-contained dry powder system shall be...

Oxidative Tritium Decontamination System

International Nuclear Information System (INIS)

Gentile, Charles A.; Parker, John J.; Guttadora, Gregory L.; Ciebiera, Lloyd P.

2002-01-01

The Princeton Plasma Physics Laboratory, Tritium Systems Group has developed and fabricated an Oxidative Tritium Decontamination System (OTDS), which is designed to reduce tritium surface contamination on various components and items. The system is configured to introduce gaseous ozone into a reaction chamber containing tritiated items that require a reduction in tritium surface contamination. Tritium surface contamination (on components and items in the reaction chamber) is removed by chemically reacting elemental tritium to tritium oxide via oxidation, while purging the reaction chamber effluent to a gas holding tank or negative pressure HVAC system. Implementing specific concentrations of ozone along with catalytic parameters, the system is able to significantly reduce surface tritium contamination on an assortment of expendable and non-expendable items. This paper will present the results of various experimentation involving employment of this system

Combustion flame-plasma hybrid reactor systems, and chemical reactant sources

Science.gov (United States)

Kong, Peter C

2013-11-26

Combustion flame-plasma hybrid reactor systems, chemical reactant sources, and related methods are disclosed. In one embodiment, a combustion flame-plasma hybrid reactor system comprising a reaction chamber, a combustion torch positioned to direct a flame into the reaction chamber, and one or more reactant feed assemblies configured to electrically energize at least one electrically conductive solid reactant structure to form a plasma and feed each electrically conductive solid reactant structure into the plasma to form at least one product is disclosed. In an additional embodiment, a chemical reactant source for a combustion flame-plasma hybrid reactor comprising an elongated electrically conductive reactant structure consisting essentially of at least one chemical reactant is disclosed. In further embodiments, methods of forming a chemical reactant source and methods of chemically converting at least one reactant into at least one product are disclosed.

Grafting of copolymer styrene maleic anhydride on poly(ethylene terephthalate) film by chemical reaction and by plasma method

Energy Technology Data Exchange (ETDEWEB)

Bigan, Muriel; Bigot, Julien [Laboratoire de Chimie Organique et Macromoleculaire (UMR 8009), Universite des Sciences et Technologies de Lille, 59655 Villeneuve d' Ascq Cedex (France); Mutel, Brigitte [Laboratoire de Genie des Procedes d' Interactions Fluides reactifs-Materiaux (UPRES-EA 3751), Batiment C5, Universite des Sciences et Technologies de Lille, 59655 Villeneuve d' Ascq Cedex (France)], E-mail: Brigitte.mutel@univ-lille1.fr; Coqueret, Xavier [Laboratoire Reactions Selectives et Applications (UMR-CNRS 6519) Universite de Reims Champagne-Ardennes, B.P. 1039, 51687 Reims Cedex 2 (France)

2008-02-15

This work deals with the chemical grafting of a styrene maleic anhydride copolymer on the surface of a previously hydrolyzed polyethylene terephthalate (PET) film 12 {mu}m thick via covalent bond. Two different ways are studied. The first one involves an activation of the hydrolyzed PET by the triethylamine before the grafting step. In the second one, the copolymer reacts with the 4-dimethylaminopyridine in order to form maleinyl pyridinium salt which reacts with alcohol function of the hydrolyzed PET. Characterization and quantification of the grafting are performed by Fourier transform infrared spectroscopy. Factorial experiment designs are used to optimize the process and to estimate experimental parameters effects. The opportunity to associate the chemical process to a cold remote nitrogen plasma one is also examined.

Chemical decontamination method in nuclear facility system

International Nuclear Information System (INIS)

Takahashi, Ryota; Sakai, Hitoshi; Oka, Shigehiro.

1996-01-01

Pumps and valves in a closed recycling loop system incorporating materials to be chemically decontaminated are decomposed, a guide plate having the decomposed parts as an exit/inlet of a decontaminating liquid is formed, and a decontaminating liquid recycling loop comprising a recycling pump and a heater is connected to the guide plate. Decontaminating liquid from a decontaminating liquid storage tank is supplied to the decontaminating liquid recycling loop. With such constitutions, the decontaminating liquid is filled in the recycling closed loop system incorporating materials to be decontaminated, and the materials to be decontaminated are chemically decontaminated. The decontaminating liquid after the decontamination is discharged and flows, if necessary, in a recycling system channel for repeating supply and discharge. After the decontamination, the guide plate is removed and returned to the original recycling loop. When pipelines of a reactor recycling system are decontaminated, the amount of decontaminations can be decreased, and reforming construction for assembling the recycling loop again, which requires cutting for pipelines in the system is no more necessary. Accordingly, the amount of wastes can be decreased, and therefore, the decontamination operation is facilitated and radiation dose can be reduced. (T.M.)

Study on chemical buffering property of GMZ sodium bentonite in air

International Nuclear Information System (INIS)

Wen Zhijian; Liu Yuemiao; Zong Zihua; Zhou Jia

2008-01-01

The high level radioactive wastes are characterized by very high initial radioactivity, the longer-lived actinides, many of actinides alpha-emitters. At present, the deep geological disposal is regarded as the most reasonable and effective way to safely disposal high-level radioactive wastes in the world. The conceptual model of HLW geological disposal in China is based on a multi-barrier system that combines an isolating geological environment with an engineered barrier system. The buffer is one of the engineered barrier materials and GMZ Na-bentonite is selected as the base material. The most important role related to buffer is chemical buffering, which means buffering of changes in water chemistry. This paper presents the experiments of GMZ-1 Na-bentonite reacted with distilled water in the air. The results and discussion of bench tests are reported. (authors)

Endocrine Disrupting Chemical Impacts on Aquatic Systems

Science.gov (United States)

Jobling, Susan

2014-07-01

We often talk about the importance of water, but one area that's often overlooked is the safety of our water supply. How many people actually think about the purity of their water when they turn on the tap? We may have real reason to be concerned because our water delivery systems and treatment technology seem to be stuck in the past, relying on old water treatment and water delivery systems. While these systems still do a great job filtering out particles, parasites and bacteria, they usually fail to remove 21st century contaminants like pesticides, industrial chemicals, lead, pharmaceuticals and arsenic. Indeed our water contains already a whole plethora of things in daily commerce and pharmaceuticals are increasingly showing up in the water supply, including antibiotics, anti-convulsants, mood altering medications and sex hormones. As the world's dependence on chemicals grows, our water supplies will continue to feel the effects, which inevitably will touch every person on this planet...

Radiolytic production of chemical fuels in fusion reactor systems

Energy Technology Data Exchange (ETDEWEB)

Fish, J D

1977-06-01

Miley's energy flow diagram for fusion reactor systems is extended to include radiolytic production of chemical fuel. Systematic study of the economics and the overall efficiencies of fusion reactor systems leads to a criterion for evaluating the potential of radiolytic production of chemical fuel as a means of enhancing the performance of a fusion reactor system. The ecumenicity of the schema is demonstrated by application to (1) tokamaks, (2) mirror machines, (3) theta-pinch reactors, (4) laser-heated solenoids, and (5) inertially confined, laser-pellet devices. Pure fusion reactors as well as fusion-fission hybrids are considered.

Radiolytic production of chemical fuels in fusion reactor systems

International Nuclear Information System (INIS)

Fish, J.D.

1977-06-01

Miley's energy flow diagram for fusion reactor systems is extended to include radiolytic production of chemical fuel. Systematic study of the economics and the overall efficiencies of fusion reactor systems leads to a criterion for evaluating the potential of radiolytic production of chemical fuel as a means of enhancing the performance of a fusion reactor system. The ecumenicity of the schema is demonstrated by application to (1) tokamaks, (2) mirror machines, (3) theta-pinch reactors, (4) laser-heated solenoids, and (5) inertially confined, laser-pellet devices. Pure fusion reactors as well as fusion-fission hybrids are considered

Nanoscale chemical state analysis of resistance random access memory device reacting with Ti

Science.gov (United States)

Shima, Hisashi; Nakano, Takashi; Akinaga, Hiro

2010-05-01

The thermal stability of the resistance random access memory material in the reducing atmosphere at the elevated temperature was improved by the addition of Ti. The unipolar resistance switching before and after the postdeposition annealing (PDA) process at 400 °C was confirmed in Pt/CoO/Ti(5 nm)/Pt device, while the severe degradation of the initial resistance occurs in the Pt/CoO/Pt and Pt/CoO/Ti(50 nm)/Pt devices. By investigating the chemical bonding states of Co, O, and Ti using electron energy loss spectroscopy combined with transmission electron microscopy, it was revealed that excess Ti induces the formation of metallic Co, while the thermal stability was improved by trace Ti. Moreover, it was indicated that the filamentary conduction path can be thermally induced after PDA in the oxide layer by analyzing electrical properties of the degraded devices. The adjustment of the reducing elements is quite essential in order to participate in their profits.

How relay protection and automatic control systems react to the energizing of a 500 kV line

Energy Technology Data Exchange (ETDEWEB)

Gusev, V S; Kokovich, V E; Ovchinnikov, V V

1966-04-01

When the three phases of a 500 to 750 KV line are switched on to load by existing types of circuit breaker, a heavy aperiodic component of current appears in the secondaries of the neutral current transformers. The dc component, although damped, has a relatively long decay period. This effect is particularly evident in the case of high speed or nonsynchronized autoreclosure. The presence of such a large dc component can cause maloperation of the line earth fault protection unless special precautions are taken. Two complementary solutions are described, preventing the first stage earth fault protection from reacting to the aperiodic component, and reducing the time constant of the CT secondary circuits.

CMOS-MEMS Chemiresistive and Chemicapacitive Chemical Sensor System

Science.gov (United States)

Lazarus, Nathan S.

Integrating chemical sensors with testing electronics is a powerful technique with the potential to lower power and cost and allow for lower system limits of detection. This thesis explores the possibility of creating an integrated sensor system intended to be embedded within respirator cartridges to notify the user that hazardous chemicals will soon leak into the face mask. For a chemical sensor designer, this application is particularly challenging due to the need for a very sensitive and cheap sensor that will be exposed to widely varying environmental conditions during use. An octanethiol-coated gold nanoparticle chemiresistor to detect industrial solvents is developed, focusing on characterizing the environmental stability and limits of detection of the sensor. Since the chemiresistor was found to be highly sensitive to water vapor, a series of highly sensitive humidity sensor topologies were developed, with sensitivities several times previous integrated capacitive humidity sensors achieved. Circuit techniques were then explored to reduce the humidity sensor limits of detection, including the analysis of noise, charge injection, jitter and clock feedthrough in a charge-based capacitance measurement (CBCM) circuit and the design of a low noise Colpitts LC oscillator. The characterization of high resistance gold nanoclusters for capacitive chemical sensing was also performed. In the final section, a preconcentrator, a heater element intended to release a brief concentrated pulse of analate, was developed and tested for the purposes of lowering the system limit of detection.

Computational Investigation of Soot and Radiation in Turbulent Reacting Flows

Science.gov (United States)

Lalit, Harshad

This study delves into computational modeling of soot and infrared radiation for turbulent reacting flows, detailed understanding of both of which is paramount in the design of cleaner engines and pollution control. In the first part of the study, the concept of Stochastic Time and Space Series Analysis (STASS) as a numerical tool to compute time dependent statistics of radiation intensity is introduced for a turbulent premixed flame. In the absence of high fidelity codes for large eddy simulation or direct numerical simulation of turbulent flames, the utility of STASS for radiation imaging of reacting flows to understand the flame structure is assessed by generating images of infrared radiation in spectral bands dominated by radiation from gas phase carbon dioxide and water vapor using an assumed PDF method. The study elucidates the need for time dependent computation of radiation intensity for validation with experiments and the need for accounting for turbulence radiation interactions for correctly predicting radiation intensity and consequently the flame temperature and NOx in a reacting fluid flow. Comparison of single point statistics of infrared radiation intensity with measurements show that STASS can not only predict the flame structure but also estimate the dynamics of thermochemical scalars in the flame with reasonable accuracy. While a time series is used to generate realizations of thermochemical scalars in the first part of the study, in the second part, instantaneous realizations of resolved scale temperature, CO2 and H2O mole fractions and soot volume fractions are extracted from a large eddy simulation (LES) to carry out quantitative imaging of radiation intensity (QIRI) for a turbulent soot generating ethylene diffusion flame. A primary motivation of the study is to establish QIRI as a computational tool for validation of soot models, especially in the absence of conventional flow field and measured scalar data for sooting flames. Realizations of

Release mitigation spray safety systems for chemical demilitarization applications.

Energy Technology Data Exchange (ETDEWEB)

Leonard, Jonathan; Tezak, Matthew Stephen; Brockmann, John E.; Servantes, Brandon; Sanchez, Andres L.; Tucker, Mark David; Allen, Ashley N.; Wilson, Mollye C.; Lucero, Daniel A.; Betty, Rita G.

2010-06-01

Sandia National Laboratories has conducted proof-of-concept experiments demonstrating effective knockdown and neutralization of aerosolized CBW simulants using charged DF-200 decontaminant sprays. DF-200 is an aqueous decontaminant, developed by Sandia National Laboratories, and procured and fielded by the US Military. Of significance is the potential application of this fundamental technology to numerous applications including mitigation and neutralization of releases arising during chemical demilitarization operations. A release mitigation spray safety system will remove airborne contaminants from an accidental release during operations, to protect personnel and limit contamination. Sandia National Laboratories recently (November, 2008) secured funding from the US Army's Program Manager for Non-Stockpile Chemical Materials Agency (PMNSCMA) to investigate use of mitigation spray systems for chemical demilitarization applications. For non-stockpile processes, mitigation spray systems co-located with the current Explosive Destruction System (EDS) will provide security both as an operational protective measure and in the event of an accidental release. Additionally, 'tented' mitigation spray systems for native or foreign remediation and recovery operations will contain accidental releases arising from removal of underground, unstable CBW munitions. A mitigation spray system for highly controlled stockpile operations will provide defense from accidental spills or leaks during routine procedures.

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

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

Computational singular perturbation analysis of stochastic chemical systems with stiffness

Science.gov (United States)

Wang, Lijin; Han, Xiaoying; Cao, Yanzhao; Najm, Habib N.

2017-04-01

Computational singular perturbation (CSP) is a useful method for analysis, reduction, and time integration of stiff ordinary differential equation systems. It has found dominant utility, in particular, in chemical reaction systems with a large range of time scales at continuum and deterministic level. On the other hand, CSP is not directly applicable to chemical reaction systems at micro or meso-scale, where stochasticity plays an non-negligible role and thus has to be taken into account. In this work we develop a novel stochastic computational singular perturbation (SCSP) analysis and time integration framework, and associated algorithm, that can be used to not only construct accurately and efficiently the numerical solutions to stiff stochastic chemical reaction systems, but also analyze the dynamics of the reduced stochastic reaction systems. The algorithm is illustrated by an application to a benchmark stochastic differential equation model, and numerical experiments are carried out to demonstrate the effectiveness of the construction.

Mass transfer with chemical reaction in multiphase systems

International Nuclear Information System (INIS)

Alper, E.

1983-01-01

These volumes deal with the phenomenon of 'mass transfer with chemical reaction' which is of industrial, biological and physiological importance. In process engineering, it is encountered both in separation processes and in reaction engineering and both aspects are covered here in four sections: introduction; gas-liquid system; liquid-liquid system; and gas-liquid-solid system

Stochastic Mapping for Chemical Plume Source Localization With Application to Autonomous Hydrothermal Vent Discovery

Science.gov (United States)

2007-02-01

silkworm moth Bombyx mori to a series of silkworm moth mimics called PheGMots (Pheromone Guided Mobile Robots). Two European groups at the University of...coastal and estuarine sea floor. Chemical plumes in these habitats are thus turbulent themselves and, like atmospheric odor plumes, consist of discrete...their habitats are typically lower than in air, and they too must react to chemical stimulus on the time scales associated with the small scale

Design and synthesis of reactive separation systems. Final report

Energy Technology Data Exchange (ETDEWEB)

Doherty, M.F.

1992-12-31

During the last decade there has been a rapid upturn in interest in reactive distillation. The chemical process industry recognizes the favorable economics of carrying out reaction simultaneously with distillation for certain classes of reacting systems, and many new processes have been built based on this technology. Interest is also increasing by academics and software vendors. Systematic design methods for reactive distillation systems have only recently begun to emerge. In this report we survey the available design techniques and point out the contributions made by our group at the University of Massachusetts.

Semi-implicit iterative methods for low Mach number turbulent reacting flows: Operator splitting versus approximate factorization

Science.gov (United States)

MacArt, Jonathan F.; Mueller, Michael E.

2016-12-01

Two formally second-order accurate, semi-implicit, iterative methods for the solution of scalar transport-reaction equations are developed for Direct Numerical Simulation (DNS) of low Mach number turbulent reacting flows. The first is a monolithic scheme based on a linearly implicit midpoint method utilizing an approximately factorized exact Jacobian of the transport and reaction operators. The second is an operator splitting scheme based on the Strang splitting approach. The accuracy properties of these schemes, as well as their stability, cost, and the effect of chemical mechanism size on relative performance, are assessed in two one-dimensional test configurations comprising an unsteady premixed flame and an unsteady nonpremixed ignition, which have substantially different Damköhler numbers and relative stiffness of transport to chemistry. All schemes demonstrate their formal order of accuracy in the fully-coupled convergence tests. Compared to a (non-)factorized scheme with a diagonal approximation to the chemical Jacobian, the monolithic, factorized scheme using the exact chemical Jacobian is shown to be both more stable and more economical. This is due to an improved convergence rate of the iterative procedure, and the difference between the two schemes in convergence rate grows as the time step increases. The stability properties of the Strang splitting scheme are demonstrated to outpace those of Lie splitting and monolithic schemes in simulations at high Damköhler number; however, in this regime, the monolithic scheme using the approximately factorized exact Jacobian is found to be the most economical at practical CFL numbers. The performance of the schemes is further evaluated in a simulation of a three-dimensional, spatially evolving, turbulent nonpremixed planar jet flame.

Effects of continuum breakdown on hypersonic aerothermodynamics for reacting flow

Science.gov (United States)

Holman, Timothy D.; Boyd, Iain D.

2011-02-01

This study investigates the effects of continuum breakdown on the surface aerothermodynamic properties (pressure, stress, and heat transfer rate) of a sphere in a Mach 25 flow of reacting air in regimes varying from continuum to a rarefied gas. Results are generated using both continuum [computational fluid dynamics (CFD)] and particle [direct simulation Monte Carlo (DSMC)] approaches. The DSMC method utilizes a chemistry model that calculates the backward rates from an equilibrium constant. A preferential dissociation model is modified in the CFD method to better compare with the vibrationally favored dissociation model that is utilized in the DSMC method. Tests of these models are performed to confirm their validity and to compare the chemistry models in both numerical methods. This study examines the effect of reacting air flow on continuum breakdown and the surface properties of the sphere. As the global Knudsen number increases, the amount of continuum breakdown in the flow and on the surface increases. This increase in continuum breakdown significantly affects the surface properties, causing an increase in the differences between CFD and DSMC. Explanations are provided for the trends observed.

System chemical biology studies of endocrine disruptors

DEFF Research Database (Denmark)

Taboureau, Olivier; Oprea, Tudor I.

Endocrine disrupting chemicals (EDCs) alter hormonal balance and other physiological systems through inappropriate developmental or adult exposure, perturbing the reproductive function of further generations. While disruption of key receptors (e.g., estrogen, androgen, and thyroid) at the ligand...

Developing chemical information system; Henbosuru kagaku joho -intanetto no sekai

Energy Technology Data Exchange (ETDEWEB)

Chihara, H.

1999-12-01

With the internet's popularization, the chemical information system greatly changes. In this paper, recent development of a chemical information system using the internet is summarized. To begin with, the kinds of online information systems using WWW and how to use them are described. Next, features of the electronic journals and how to use them are described. Next, CAS and STN as internet editions of the secondary information are introduced. Next, the Scifinder and the SciFinder Scholar which CAS developed as information retrieval tools for researcher are explained well. Next, ISI and DIALOG are introduced as information retrieval services of the other web editions. Finally, realization of retrieval and display of the English database by Japanese and preparation of a fact database such as density, boiling point, spectra, etc. and the offer of them by the internet are mentioned as a future image of chemical information systems. (NEDO)

Radiated flow of chemically reacting nanoliquid with an induced magnetic field across a permeable vertical plate

Directory of Open Access Journals (Sweden)

B. Mahanthesh

Full Text Available Impact of induced magnetic field over a flat porous plate by utilizing incompressible water-copper nanoliquid is examined analytically. Flow is supposed to be laminar, steady and two-dimensional. The plate is subjected to a regular free stream velocity as well as suction velocity. Flow formulation is developed by considering Maxwell–Garnetts (MG and Brinkman models of nanoliquid. Impacts of thermal radiation, viscous dissipation, temperature dependent heat source/sink and first order chemical reaction are also retained. The subjected non-linear problems are non-dimensionalized and analytic solutions are presented via series expansion method. The graphs are plotted to analyze the influence of pertinent parameters on flow, magnetism, heat and mass transfer fields as well as friction factor, current density, Nusselt and Sherwood numbers. It is found that friction factor at the plate is more for larger magnetic Prandtl number. Also the rate of heat transfer decayed with increasing nanoparticles volume fraction and the strength of magnetism. Keywords: Induced magnetic field, Nanoliquids, Heat source/sink, Series expansion method, Chemical reaction, Thermal radiation

Systems analysis of past, present, and future chemical terrorism scenarios.

Energy Technology Data Exchange (ETDEWEB)

Hoette, Trisha Marie

2012-03-01

Throughout history, as new chemical threats arose, strategies for the defense against chemical attacks have also evolved. As a part of an Early Career Laboratory Directed Research and Development project, a systems analysis of past, present, and future chemical terrorism scenarios was performed to understand how the chemical threats and attack strategies change over time. For the analysis, the difficulty in executing chemical attack was evaluated within a framework of three major scenario elements. First, historical examples of chemical terrorism were examined to determine how the use of chemical threats, versus other weapons, contributed to the successful execution of the attack. Using the same framework, the future of chemical terrorism was assessed with respect to the impact of globalization and new technologies. Finally, the efficacy of the current defenses against contemporary chemical terrorism was considered briefly. The results of this analysis justify the need for continued diligence in chemical defense.

An Experimental Framework for Generating Evolvable Chemical Systems in the Laboratory

Science.gov (United States)

Baum, David A.; Vetsigian, Kalin

2017-12-01

Most experimental work on the origin of life has focused on either characterizing the chemical synthesis of particular biochemicals and their precursors or on designing simple chemical systems that manifest life-like properties such as self-propagation or adaptive evolution. Here we propose a new class of experiments, analogous to artificial ecosystem selection, where we select for spontaneously forming self-propagating chemical assemblages in the lab and then seek evidence of a response to that selection as a key indicator that life-like chemical systems have arisen. Since surfaces and surface metabolism likely played an important role in the origin of life, a key experimental challenge is to find conditions that foster nucleation and spread of chemical consortia on surfaces. We propose high-throughput screening of a diverse set of conditions in order to identify combinations of "food," energy sources, and mineral surfaces that foster the emergence of surface-associated chemical consortia that are capable of adaptive evolution. Identification of such systems would greatly advance our understanding of the emergence of self-propagating entities and the onset of adaptive evolution during the origin of life.

Simplified mathematical model for heat supply and removal with allowance for chemical reaction kinetics in the N2O4 reversible 2NO2 reversible 2NO + O2 system

International Nuclear Information System (INIS)

Shiryaeva, N.M.

1977-01-01

The processes of heat supply and removal with chemical reactions proceeding in the circuit are usually described by a set of nonlinear ordinary differential equations. Considering a non-equilibrium state of a chemically reacting gas relative to equilibrium, to which the nonequilibrium system approaches according to a certain process and applying the Tailor series expansion near this equilibrium point, a set of differential equations can be reduced to one differential and some algebraic equations. The analysis shows that of the differential equation obtained can be quasilinearized, and then the linear differential equation can be solved. On the basis of the analytical solutions obtained the calculations of flow parameters have been performed for the cases of cooling and heating the dissociating coolant in channels of a constant cross-section at various pressures. The calculation results are in a satisfactory agreement with the numerical solution of a set of differential equations performed on the ''Minsk-22'' computer. The solution may be applied to calculate isobaric processes in thermodynamic cycles, where the N 2 O 4 coolant is used

Non-equilibrium reacting gas flows kinetic theory of transport and relaxation processes

CERN Document Server

Nagnibeda, Ekaterina; Nagnibeda, Ekaterina

2009-01-01

This volume develops the kinetic theory of transport phenomena and relaxation processes in the flows of reacting gas mixtures. The theory is applied to the modeling of non-equilibrium flows behind strong shock waves, in the boundary layer, and in nozzles.

Virtual Exploration of the Ring Systems Chemical Universe.

Science.gov (United States)

Visini, Ricardo; Arús-Pous, Josep; Awale, Mahendra; Reymond, Jean-Louis

2017-11-27

Here, we explore the chemical space of all virtually possible organic molecules focusing on ring systems, which represent the cyclic cores of organic molecules obtained by removing all acyclic bonds and converting all remaining atoms to carbon. This approach circumvents the combinatorial explosion encountered when enumerating the molecules themselves. We report the chemical universe database GDB4c containing 916 130 ring systems up to four saturated or aromatic rings and maximum ring size of 14 atoms and GDB4c3D containing the corresponding 6 555 929 stereoisomers. Almost all (98.6%) of these ring systems are unknown and represent chiral 3D-shaped macrocycles containing small rings and quaternary centers reminiscent of polycyclic natural products. We envision that GDB4c can serve to select new ring systems from which to design analogs of such natural products. The database is available for download at www.gdb.unibe.ch together with interactive visualization and search tools as a resource for molecular design.

'REACTS'. A pragmatic approach for providing medical care and physician education for radiation emergencies

International Nuclear Information System (INIS)

Lushbaugh, C.C.; Andrews, G.A.; Huebner, K.F.; Cloutier, R.J.; Beck, W.L.; Berger, J.D.

1976-01-01

Because serious radiation incidents have been rare, few medical personnel (notably only some in France, Russia, Belgium, Canada, Yugoslavia, Japan, Great Britain and the United States) have first-hand experience in radiation-accident management. The generation of physicians who participated in those accidents now needs to pass on the bits of knowledge that were gleaned from them. These case histories are difficult for the local, non-radiology physician to obtain when he is called upon to help formulate the medical-emergency response plan required everywhere for licensing power reactors. The Radiation Emergency Assistance Center and Training Site (REACTS) in Oak Ridge, Tennessee, supported by the US Energy Research and Development Administration, is designed to meet these medical and educational needs. REACTS, located in the Oak Ridge Hospital of the Methodist Church, is not involved in the hospital's daily community functions except insofar as REACTS is the radiation emergency arm of the area's major disaster plan. Its dual mission is training physicians, nurses, and paramedical emergency personnel in radiation-accident management, and treating irradiated and contaminated persons. Its training activities are carried out by the Special Training Division of Oak Ridge Associated Universities. Formal courses in radiation medicine and health physics and practical laboratory experience are now conducted twice a year for physicians. They will be expanded in the future to include training of paramedical personnel. Follow-up studies of radiation-accident survivors are carried out in REACTS to ensure the preservation of valuable human data and radiation-accident experiences. This unique facility and its staff are dedicated to meet the needs of the far-flung public and private medical domains in the United States for nuclear-production energy

Tax havens under international pressure: How do they react?

OpenAIRE

Patrice Pieretti; Giuseppe Pulina

2015-01-01

This paper contributes to the literature about tax havens by providing a more comprehensive analysis of their role. The aim is to analyze how low-tax jurisdictions can react to growing international pressure exerted, by high-tax countries, to enforce compliance with anti aggressive tax planning standards. To this end, we model how a small tax haven tries to be attractive to multinationals located in a high-tax region by providing aggressive tax planning services and/or a favorable environment...

Hyperchaos and chaotic hierarchy in low-dimensional chemical systems

Science.gov (United States)

Baier, Gerold; Sahle, Sven

1994-06-01

Chemical reaction chains with feedback of one of the products on the source of the chain are considered. A strategy is presented in terms of ordinary differential equations which creates one, two, and three positive Lyapunov exponents as the finite dimension of the system is increased. In particular, a nonlinear inhibition loop in a chemical reaction sequence controls the type of chaos. The bifurcation scenarios are studied and chaos and hyperchaos are found for broad regions of bifurcation parameter. Some implications for the occurrence of higher chaos in real systems are discussed.

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

Energy Technology Data Exchange (ETDEWEB)

1980-02-01

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

Responding to excessive alcohol consumption in third-level (REACT): a study protocol.

Science.gov (United States)

Davoren, Martin P; Calnan, Susan; Mulcahy, Judith; Lynch, Emily; Perry, Ivan J; Byrne, Michael

2018-05-11

Problem alcohol use is an ongoing, worldwide phenomenon of considerable concern. Throughout the past 20 years, national policies have noted the importance of students when tackling alcohol consumption. Considering alcohol is a multifaceted issue, a multi-component response is required to combat its excessive use. This protocol sets out the approach used for developing, implementing and evaluating the REACT (Responding to Excessive Alcohol Consumption in Third-level) Programme. This evaluation will provide the evidence base for programme development, implementation and improvement. Stage one involved defining the multi-component intervention. This was developed following a systematic review of existing literature and a Delphi-consensus workshop involving university students, staff and relevant stakeholders. Following this, the programme is being implemented across the Higher Education sector in Ireland. A number of Higher Education Institutes have declined the invitation to participate in the programme. These institutions will act as control sites. Each intervention site will have a steering committee whose membership will include a mix of students and academic and student service staff. This steering committee will report to the REACT research team on the implementation of mandatory and optional action points at local sites. An online cross-sectional study at baseline and two-years post intervention will be utilised to determine the impact of the REACT programme. The impact assessment will focus on (1) whether the intervention has reduced alcohol consumption among third-level students (2); whether the programme altered students attitudes toward alcohol and (3) whether the programme has decreased the second-hand effects associated with excessive consumption. Finally, qualitative research will focus on factors influencing the take-up and implementation of this programme as well as students' views on the initiative. Alcohol consumption has remained on the policy

CHEMTRAN and the Interconversion of Chemical Substructure Systems

Science.gov (United States)

Granito, Charles E.

1973-01-01

The need for the interconversion of chemical substructure systems is discussed and CHEMTRAN, a new service, designed especially for creating interconversion programs, is introduced. (7 references) (Author)

Versatile Dual Photoresponsive System for Precise Control of Chemical Reactions.

Science.gov (United States)

Xu, Can; Bing, Wei; Wang, Faming; Ren, Jinsong; Qu, Xiaogang

2017-08-22

A versatile method for photoregulation of chemical reactions was developed through a combination of near-infrared (NIR) and ultraviolet (UV) light sensitive materials. This regulatory effect was achieved through photoresponsive modulation of reaction temperature and pH values, two prominent factors influencing reaction kinetics. Photothermal nanomaterial graphene oxide (GO) and photobase reagent malachite green carbinol base (MGCB) were selected for temperature and pH regulation, respectively. Using nanocatalyst- and enzyme-mediated chemical reactions as model systems, we demonstrated the feasibility and high efficiency of this method. In addition, a photoresponsive, multifunctional "Band-aid"-like hydrogel platform was presented for programmable wound healing. Overall, this simple, efficient, and reversible system was found to be effective for controlling a wide variety of chemical reactions. Our work may provide a method for remote and sustainable control over chemical reactions for industrial and biomedical applications.

Combustion science and engineering

CERN Document Server

Annamalai, Kalyan

2006-01-01

Introduction and Review of Thermodynamics Introduction Combustion Terminology Matter and Its Properties Microscopic Overview of Thermodynamics Conservation of Mass and Energy and the First Law of Thermodynamics The Second Law of Thermodynamics Summary Stoichiometry and Thermochemistry of Reacting Systems Introduction Overall Reactions Gas Analyses Global Conservation Equations for Reacting Systems Thermochemistry Summary Appendix Reaction Direction and Equilibrium Introduction Reaction Direction and Chemical Equilibrium Chemical Equilibrium Relations Vant Hoff Equation Adi

THE STABILITY OF OPTICALLY THIN REACTING PLASMAS: EFFECTS OF THE BULK VISCOSITY

International Nuclear Information System (INIS)

Ibanez S, Miguel H.

2009-01-01

The thermochemical stability of reacting plasmas is analyzed by taking into account the change in the thermodynamical equilibrium values during the fluctuation. This shift in the equilibrium produces two main effects: a change in the four instability criteria for reacting gases resulting when the above effect is neglected and adds a fifth instability criterion due to the fact that the corresponding secular equation becomes a fifth-order polynomial. The above results are applied to several plasma models, in particular, to a photoionized hydrogen plasma for which the bulk viscosity can be more important than the dynamic viscosity and the thermometric conductivity. Therefore, the bulk viscosity may quench thermochemical instabilities were the thermal conduction is unable of stabilizing. This occurs for low values of the photoionizing energy E. The implications of the above results in explaining the formation of clump structures in different regions of the interstellar medium are outlined.

Selective chemical detection by energy modulation of sensors

Science.gov (United States)

Stetter, J.R.; Otagawa, T.

1985-05-20

A portable instrument for use in the field in detecting, identifying, and quantifying a component of a sampled fluid includes a sensor which chemically reacts with the component of interest or a derivative thereof, an electrical heating filament for heating the sample before it is applied to the sensor, and modulating means for continuously varying the temperature of the filament (and hence the reaction rate) between two values sufficient to produce the chemical reaction. In response to this thermal modulation, the sensor produces a modulated output signal, the modulation of which is a function of the activation energy of the chemical reaction, which activation energy is specific to the particular component of interest and its concentration. Microprocessor means compares the modulated output signal with standard responses for a plurality of components to identify and quantify the particular component of interest. 4 figs.

Thermocouple-based Temperature Sensing System for Chemical Cell Inside Micro UAV Device

Science.gov (United States)

Han, Yanhui; Feng, Yue; Lou, Haozhe; Zhang, Xinzhao

2018-03-01

Environmental temperature of UAV system is crucial for chemical cell component inside. Once the temperature of this chemical cell is over 259 °C and keeps more than 20 min, the high thermal accumulation would result in an explosion, which seriously damage the whole UAV system. Therefore, we develop a micro temperature sensing system for monitoring the temperature of chemical cell thermally influenced by UAV device deployed in a 300 °C temperature environment, which is quite useful for insensitive munitions and UAV safety enhancement technologies.

A portable system for nuclear, chemical agent, and explosives identification

International Nuclear Information System (INIS)

Parker, W.E.; Buckley, W.M.; Kreek, S.A.; Mauger, G.J.; Lavietes, A.D.; Dougan, A.D.; Caffrey, A.J.

2001-01-01

The FRIS/PINS hybrid integrates the LLNL-developed Field Radionuclide Identification System (FRIS) with the INEEL-developed Portable Isotopic Neutron Spectroscopy (PINS) chemical assay system to yield a combined general radioisotope, special nuclear material, and chemical weapons/explosives detection and identification system. The PINS system uses a neutron source and a high-purity germanium γ-ray detector. The FRIS system uses an electromechanically cooled germanium detector and its own analysis software to detect and identify special nuclear material and other radioisotopes. The FRIS/PINS combined system also uses the electromechanically-cooled germanium detector. There is no other currently available integrated technology that can combine a prompt-gamma neutron-activation analysis capability for CWE with a passive radioisotope measurement and identification capability for special nuclear material

A Portable System for Nuclear, Chemical Agent and Explosives Identification

International Nuclear Information System (INIS)

Parker, W.E.; Buckley, W.M.; Kreek, S.A.; Caffrey, A.J.; Mauger, G.J.; Lavietes, A.D.; Dougan, A.D.

2000-01-01

The FRIS/PINS hybrid integrates the LLNL-developed Field Radionuclide Identification System (FRIS) with the INEEL-developed Portable Isotopic Neutron Spectroscopy (PINS) chemical assay system to yield a combined general radioisotope, special nuclear material, and chemical weapons/explosives detection and identification system. The PINS system uses a neutron source and a high-purity germanium γ-ray detector. The FRIS system uses an electrochemically cooled germanium detector and its own analysis software to detect and identify special nuclear material and other radioisotopes. The FRIS/PINS combined system also uses the electromechanically-cooled germanium detector. There is no other currently available integrated technology that can combine an active neutron interrogation and analysis capability for CWE with a passive radioisotope measurement and identification capability for special nuclear material

Insect-gene-activity detection system for chemical and biological warfare agents and toxic industrial chemicals

Science.gov (United States)

Mackie, Ryan S.; Schilling, Amanda S.; Lopez, Arturo M.; Rayms-Keller, Alfredo

2002-02-01

Detection of multiple chemical and biological weapons (CBW) agents and/or complex mixtures of toxic industrial chemicals (TIC) is imperative for both the commercial and military sectors. In a military scenario, a multi-CBW attack would create confusion, thereby delaying decontamination and therapeutic efforts. In the commercial sector, polluted sites invariably contain a mixture of TIC. Novel detection systems capable of detecting CBW and TIC are sorely needed. While it may be impossible to build a detector capable of discriminating all the possible combinations of CBW, a detection system capable of statistically predicting the most likely composition of a given mixture is within the reach of current emerging technologies. Aquatic insect-gene activity may prove to be a sensitive, discriminating, and elegant paradigm for the detection of CBW and TIC. We propose to systematically establish the expression patterns of selected protein markers in insects exposed to specific mixtures of chemical and biological warfare agents to generate a library of biosignatures of exposure. The predicting capabilities of an operational library of biosignatures of exposures will allow the detection of emerging novel or genetically engineered agents, as well as complex mixtures of chemical and biological weapons agents. CBW and TIC are discussed in the context of war, terrorism, and pollution.

Materials study for reacting plasma machine

International Nuclear Information System (INIS)

Kamada, Kohji; Hamada, Yasuji

1982-01-01

A new reacting plasma machine is designed, and will be constructed at the Institute of Plasma Physics, Nagoya University. It is important to avoid the activation of the materials for the machine, accordingly, aluminum alloy has been considered as the material since the induced activity of aluminum due to 14 MeV neutrons is small. The vacuum chamber of the new machine consists of four modules, and the remote control of each module is considered. However, the cost of the remote control of modules is expensive. To minimize the dependence on the remote control, the use of aluminum alloy is considered as the first step. The low electrical resistivity, over-ageing, weak mechanical strength and eddy current characteristics of aluminum alloy must be improved. The physical and electrical properties of various aluminum alloys have been investigated. Permeability of hydrogen through aluminum, the recycling characteristics and surface coating materials have been also studied. (Kato, T.)

COMPUTER SUPPORT SYSTEMS FOR ESTIMATING CHEMICAL TOXICITY: PRESENT CAPABILITIES AND FUTURE TRENDS

Science.gov (United States)

Computer Support Systems for Estimating Chemical Toxicity: Present Capabilities and Future Trends A wide variety of computer-based artificial intelligence (AI) and decision support systems exist currently to aid in the assessment of toxicity for environmental chemicals. T...

An LES-PBE-PDF approach for modeling particle formation in turbulent reacting flows

Science.gov (United States)

Sewerin, Fabian; Rigopoulos, Stelios

2017-10-01

Many chemical and environmental processes involve the formation of a polydispersed particulate phase in a turbulent carrier flow. Frequently, the immersed particles are characterized by an intrinsic property such as the particle size, and the distribution of this property across a sample population is taken as an indicator for the quality of the particulate product or its environmental impact. In the present article, we propose a comprehensive model and an efficient numerical solution scheme for predicting the evolution of the property distribution associated with a polydispersed particulate phase forming in a turbulent reacting flow. Here, the particulate phase is described in terms of the particle number density whose evolution in both physical and particle property space is governed by the population balance equation (PBE). Based on the concept of large eddy simulation (LES), we augment the existing LES-transported probability density function (PDF) approach for fluid phase scalars by the particle number density and obtain a modeled evolution equation for the filtered PDF associated with the instantaneous fluid composition and particle property distribution. This LES-PBE-PDF approach allows us to predict the LES-filtered fluid composition and particle property distribution at each spatial location and point in time without any restriction on the chemical or particle formation kinetics. In view of a numerical solution, we apply the method of Eulerian stochastic fields, invoking an explicit adaptive grid technique in order to discretize the stochastic field equation for the number density in particle property space. In this way, sharp moving features of the particle property distribution can be accurately resolved at a significantly reduced computational cost. As a test case, we consider the condensation of an aerosol in a developed turbulent mixing layer. Our investigation not only demonstrates the predictive capabilities of the LES-PBE-PDF model but also

ReACT Methodology Proof of Concept Final Report

Energy Technology Data Exchange (ETDEWEB)

Bri Rolston; Sarah Freeman

2014-03-01

The Department of Energy’s Office of Electricity Delivery and Energy Reliability (DOE-OE) funded INL Researchers to evaluate a novel process for assessing and mitigating cyber security risks. The proof of concept level of the method was tested in an industry environment. This case study, plus additional case studies will support the further development of the method into a tool to assist industry in securing their critical networks. This report provides an understanding of the process developed in the Response Analysis and Characterization Tool (ReACT) project. This report concludes with lessons learned and a roadmap for final development of these tools for use by industry.

Self-regulating chemo-mechano-chemical systems

Science.gov (United States)

Aizenberg, Joanna; He, Ximin; Aizenberg, Michael

2017-05-16

A chemo-mechano-chemical (C.sub.1-M-C.sub.2) system includes a base supporting an actuatable structure, said structure comprising a functionalized portion and being embedded in an environmentally responsive gel capable of volume change in response to an environmental stimulus; a first fluid layer disposed over the base and in contact with the actuatable structure, said first fluid layer comprising the environmentally responsive gel; and a second fluid layer in contact with the actuatable structure, wherein the layers are positioned such that the functionalized portion is in contact with the second layer in a first relaxed state and in contact with the first layer in a second actuated state and wherein the functionalized portion interacts with at least one of the layers to provide a chemical or physical response.

Chemical Hydride Slurry for Hydrogen Production and Storage

Energy Technology Data Exchange (ETDEWEB)

McClaine, Andrew W

2008-09-30

The purpose of this project was to investigate and evaluate the attractiveness of using a magnesium chemical hydride slurry as a hydrogen storage, delivery, and production medium for automobiles. To fully evaluate the potential for magnesium hydride slurry to act as a carrier of hydrogen, potential slurry compositions, potential hydrogen release techniques, and the processes (and their costs) that will be used to recycle the byproducts back to a high hydrogen content slurry were evaluated. A 75% MgH₂ slurry was demonstrated, which was just short of the 76% goal. This slurry is pumpable and storable for months at a time at room temperature and pressure conditions and it has the consistency of paint. Two techniques were demonstrated for reacting the slurry with water to release hydrogen. The first technique was a continuous mixing process that was tested for several hours at a time and demonstrated operation without external heat addition. Further work will be required to reduce this design to a reliable, robust system. The second technique was a semi-continuous process. It was demonstrated on a 2 kWh scale. This system operated continuously and reliably for hours at a time, including starts and stops. This process could be readily reduced to practice for commercial applications. The processes and costs associated with recycling the byproducts of the water/slurry reaction were also evaluated. This included recovering and recycling the oils of the slurry, reforming the magnesium hydroxide and magnesium oxide byproduct to magnesium metal, hydriding the magnesium metal with hydrogen to form magnesium hydride, and preparing the slurry. We found that the SOM process, under development by Boston University, offers the lowest cost alternative for producing and recycling the slurry. Using the H2A framework, a total cost of production, delivery, and distribution of $4.50/kg of hydrogen delivered or $4.50/gge was determined. Experiments performed at Boston

Fourier transform infrared spectra applications to chemical systems

CERN Document Server

Ferraro, John R

1978-01-01

Fourier Transform Infrared Spectroscopy: Applications to Chemical Systems presents the chemical applications of the Fourier transform interferometry (FT-IR).The book contains discussions on the applications of FT-IR in the fields of chromatography FT-IR, polymers and biological macromolecules, emission spectroscopy, matrix isolation, high-pressure interferometry, and far infrared interferometry. The final chapter is devoted to the presentation of the use of FT-IR in solving national technical problems such as air pollution, space exploration, and energy related subjects.Researc

Chemical characteristics and enhanced hepatoprotective activities of Maillard reaction products derived from milk protein-sugar system.

Science.gov (United States)

Oh, Nam Su; Young Lee, Ji; Lee, Hyun Ah; Joung, Jae Yeon; Shin, Yong Kook; Kim, Sae Hun; Kim, Younghoon; Lee, Kwang Won

2016-02-01

The objective of this study was to investigate the characteristics, antioxidative properties, and hepatoprotective effects of Maillard reaction products (MRP) from milk protein reacted with sugars. The MRP were obtained from milk protein, whey protein concentrates and sodium caseinate, using 2 types of sugars, lactose and glucose, by heating the mixture at 55°C for 7d in a sodium phosphate buffer (pH 7.4). Changes in the chemical modification of the milk protein were monitored by measuring the protein-bound carbonyls and PAGE protein profiles. The results showed that the amount of protein-bound carbonyls increased after Maillard reaction (MR). In addition, sodium dodecyl sulfate-PAGE analysis indicated a formation of high-molecular weight complexes through MR. The modification sites induced by MR of milk protein were monitored by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry analysis of tryptic-digested gel spots of MRP. As a result, modification and their localization in AA sequence of MRP was identified. Also, the MRP showed higher antioxidant activities than the intact milk protein, and they reduced intracellular reactive oxygen species production and inhibited the depletion of the reduced glutathione concentrations in the HepG2 cells. In particular, glucose-sodium caseinate MRP showed the highest biological activities among all MRP. Therefore, these results suggest that the MRP from milk protein reacting with sugars possess effective antioxidant activity and have a protective ability against oxidative damage. Copyright © 2016 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Full system chemical decontamination used in nuclear decommissioning

International Nuclear Information System (INIS)

Elder, George; Rottner, Bernard; Braehler, Georg

2012-01-01

The decommissioning of nuclear power stations at the end of the operational period of electricity generation offers technical challenges in the safe dismantling of the facility and the minimization of radioactive waste arising from the decommissioning activities. These challenges have been successfully overcome as demonstrated by decommissioning of the first generation of nuclear power plants. One of the techniques used in decommissioning is that of chemical decontamination which has a number of functions and advantages as given here: 1. Removal of contamination from metal surfaces in the reactors cooling systems. 2. Reduction of radioactive exposure to decommissioning workers 3. Minimization of metal waste by decontamination and recycling of metal components 4. Control of contamination when dismantling reactor and waste systems 5. Reduction in costs due to lower radiation fields, lower contamination levels and minimal metal waste volume for disposal. One such chemical decontamination technology was developed for the Electric Power Research Institute (EPRI) by Bradtec (Bradtec is an ONET Technologies subsidiary) and is known as the EPRI DFD system. This paper gives a description of the EPRI DFD system, and highlights the experience using the system. (orig.)

Possibility of the development of a Serbian protection system against chemical accidents

Directory of Open Access Journals (Sweden)

Dejan R. Inđić

2012-10-01

Full Text Available The paper presents a draft of a system model for responding in case of chemical accidents in accordance with the current legislation regarding the environment protection, the structure and elements of the existing response system in case of chemical accidents, other works dealing with the issue as well as the prospects planned by those responsible for the environmental protection. The paper discuss the possibilities of different institutions and agencies of the Republic of Serbia to engage in specialized methods of cooperation and protection against chemical hazards in accordance with Article X of the Convention on the Prohibition of Chemical Weapons.

Formal modeling of a system of chemical reactions under uncertainty.

Science.gov (United States)

Ghosh, Krishnendu; Schlipf, John

2014-10-01

We describe a novel formalism representing a system of chemical reactions, with imprecise rates of reactions and concentrations of chemicals, and describe a model reduction method, pruning, based on the chemical properties. We present two algorithms, midpoint approximation and interval approximation, for construction of efficient model abstractions with uncertainty in data. We evaluate computational feasibility by posing queries in computation tree logic (CTL) on a prototype of extracellular-signal-regulated kinase (ERK) pathway.

Studies on the different forms of material reacting with antiinsulin antibodies in the fetal and adult rat

International Nuclear Information System (INIS)

Felix, J.M.; Sutter-Dub, M.T.; Legrele, C.; Reims Univ., 51

1975-01-01

The nature of peak B (MW = 10-12,000, proinsulin) and peak C (MW = 50-100,000, 'big big' insulin) materials detected by the double antibody (DA) procedure in elution profiles of rat sera after Sephadex G 50 or G 100 chromatography (cf. preceding companion paper) is further investigated. Peak B is converted by mild tryptic digestion in an immunoreactive material behaving in rechromatography exactly like insulin monomer. Peak C is less easily detected by the dextran coated charcoal (DCC) method; it resists 8 M urea 37 0 C for 1 hr, is not an artifact due to the complement system; its relative importance is very much reduced in pancreatic extracts or perifusates. Incubation of biologically active 125 I labelled insulin in rat sera results in appearance of labelled material behaving on chromatography like peak C natural material, having the electrophoretic mobility of rat α 1 globulins and albumin, and resisting 8 M urea, acidic pHs and 0.5 M NaCl. Similar incubation in buffer supplemented with bovine albumin results in appearance of a labelled material having the electrophoretic mobility of beef albumin; N-ethyl-maleimide provides against this binding, which might result from (S-S)-(SH) interchanges. Rat α globulins and albumin (but not beef albumin) cross-react with the DA procedure; they do not react with the DCC method. Insulin bound to plasma proteins react with both methods. It is suggested that peak C material, as detected by the DA method in rat serum, consists both of insulin covalently bound to plasma proteins and of certain plasma proteins; the DCC method detects only bound insulin. In streptozotocin treated rats, peak C material persists after the complete disappearance of insulin and proinsulin when detected by the (DA) procedure, but disappears when detected by the DCC procedure. (orig.) [de

Studies on the different forms of material reacting with antiinsulin antibodies in the fetal and adult rat

Energy Technology Data Exchange (ETDEWEB)

Felix, J M; Sutter-Dub, M T; Legrele, C [Reims Univ., 51 (France). Lab. de Physiologie Animale; Reims Univ., 51 (France). Centre de Biologie et de Biochimie du Developpement)

1975-09-01

The nature of peak B (MW = 10-12,000, proinsulin) and peak C (MW = 50-100,000, 'big big' insulin) materials detected by the double antibody (DA) procedure in elution profiles of rat sera after Sephadex G 50 or G 100 chromatography (cf. preceding companion paper) is further investigated. Peak B is converted by mild tryptic digestion in an immunoreactive material behaving in rechromatography exactly like insulin monomer. Peak C is less easily detected by the dextran coated charcoal (DCC) method; it resists 8 M urea 37/sup 0/C for 1 hr, is not an artifact due to the complement system; its relative importance is very much reduced in pancreatic extracts or perifusates. Incubation of biologically active /sup 125/I labelled insulin in rat sera results in appearance of labelled material behaving on chromatography like peak C natural material, having the electrophoretic mobility of rat ..cap alpha../sub 1/ globulins and albumin, and resisting 8 M urea, acidic pHs and 0.5 M NaCl. Similar incubation in buffer supplemented with bovine albumin results in appearance of a labelled material having the electrophoretic mobility of beef albumin; N-ethyl-maleimide provides against this binding, which might result from (S-S)-(SH) interchanges. Rat ..cap alpha.. globulins and albumin (but not beef albumin) cross-react with the DA procedure; they do not react with the DCC method. Insulin bound to plasma proteins react with both methods. It is suggested that peak C material, as detected by the DA method in rat serum, consists both of insulin covalently bound to plasma proteins and of certain plasma proteins; the DCC method detects only bound insulin. In streptozotocin treated rats, peak C material persists after the complete disappearance of insulin and proinsulin when detected by the (DA) procedure, but disappears when detected by the DCC procedure.

A novel class of chemicals that react with abasic sites in DNA and specifically kill B cell cancers.

Directory of Open Access Journals (Sweden)

Shanqiao Wei

Full Text Available Most B cell cancers overexpress the enzyme activation-induced deaminase at high levels and this enzyme converts cytosines in DNA to uracil. The constitutive expression of this enzyme in these cells greatly increases the uracil content of their genomes. We show here that these genomes also contain high levels of abasic sites presumably created during the repair of uracils through base-excision repair. We further show that three alkoxyamines with an alkyne functional group covalently link to abasic sites in DNA and kill immortalized cell lines created from B cell lymphomas, but not other cancers. They also do not kill normal B cells. Treatment of cancer cells with one of these chemicals causes strand breaks, and the sensitivity of the cells to this chemical depends on the ability of the cells to go through the S phase. However, other alkoxyamines that also link to abasic sites- but lack the alkyne functionality- do not kill cells from B cell lymphomas. This shows that the ability of alkoxyamines to covalently link to abasic sites is insufficient for their cytotoxicity and that the alkyne functionality may play a role in it. These chemicals violate the commonly accepted bioorthogonality of alkynes and are attractive prototypes for anti-B cell cancer agents.

ANALYTICAL SYNTHESIS OF CHEMICAL REACTOR CONTROL SYSTEM

Directory of Open Access Journals (Sweden)

Alexander Labutin

2017-02-01

Full Text Available The problem of the analytical synthesis of the synergetic control system of chemical reactor for the realization of a complex series-parallel exothermal reaction has been solved. The synthesis of control principles is performed using the analytical design method of aggregated regulators. Synthesized nonlinear control system solves the problem of stabilization of the concentration of target component at the exit of reactor and also enables one to automatically transfer to new production using the equipment.

IgE antibodies of fish allergic patients cross-react with frog parvalbumin.

Science.gov (United States)

Hilger, C; Thill, L; Grigioni, F; Lehners, C; Falagiani, P; Ferrara, A; Romano, C; Stevens, W; Hentges, F

2004-06-01

The major allergens in fish are parvalbumins. Important immunoglobulin (Ig)E cross-recognition of parvalbumins from different fish species has been shown. Recently frog parvalbumin alpha has been found to be responsible for a case of IgE-mediated anaphylaxis triggered by the ingestion of frog meat. The aim of this study was to investigate whether IgE antibodies of fish allergic persons cross-react with frog parvalbumin and to appreciate its clinical relevance. The sera of 15 fish allergic patients and one fish and frog allergic patient were tested by IgE-immunoblotting against frog muscle extract. Sera were tested against recombinant parvalbumin alpha and beta from Rana esculenta. Skin prick tests were performed in selected patients with recombinant frog parvalbumin. Ca(2+) depletion experiments and inhibition studies with purified cod and frog recombinant parvalbumin were done to characterize the cross-reactive pattern. Fourteen of the sera tested had IgE antibodies recognizing low molecular weight components in frog muscle extract. Calcium depletion experiments or inhibition of patient sera with purified cod parvalbumin led to a significant or complete decrease in IgE binding. When tested against recombinant parvalbumins, three of 13 sera reacted with alpha parvalbumin and 11 of 12 reacted with beta parvalbumin from R. esculenta. Skin prick tests performed with recombinant frog parvalbumin were positive in fish allergic patients. Inhibition studies showed that a fish and frog allergic patient was primarily sensitized to fish parvalbumin. Cod parvalbumin, a major cross-reactive allergen among different fish species, shares IgE binding epitopes with frog parvalbumin. This in vitro cross-reactivity seems to be also clinically relevant. Parvalbumins probably represent a new family of cross-reactive allergens.

Alcohols react with MCM-41 at room temperature and chemically modify mesoporous silica.

Science.gov (United States)

Björklund, Sebastian; Kocherbitov, Vitaly

2017-08-30

Mesoporous silica has received much attention due to its well-defined structural order, high surface area, and tunable pore diameter. To successfully employ mesoporous silica for nanotechnology applications it is important to consider how it is influenced by solvent molecules due to the fact that most preparation procedures involve treatment in various solvents. In the present work we contribute to this important topic with new results on how MCM-41 is affected by a simple treatment in alcohol at room temperature. The effects of alcohol treatment are characterized by TGA, FTIR, and sorption calorimetry. The results are clear and show that treatment of MCM-41 in methanol, ethanol, propanol, butanol, pentanol, or octanol at room temperature introduces alkoxy groups that are covalently bound to the silica surface. It is shown that alcohol treated MCM-41 becomes more hydrophobic and that this effect is sequentially more prominent going from methanol to octanol. Chemical formation of alkoxy groups onto MCM-41 occurs both for calcined and hydroxylated MCM-41 and the alkoxy groups are hydrolytically unstable and can be replaced by silanol groups after exposure to water. The results are highly relevant for mesoporous silica applications that involve contact or treatment in protic solvents, which is very common.

Development of a Chemical Equilibrium Model for a Molten Core-Concrete Interaction Analysis Module

Energy Technology Data Exchange (ETDEWEB)

Seo, Jae Uk; Lee, Dae Young; Park, Chang Hwan [FNC Technology Co., Yongin (Korea, Republic of)

2016-10-15

This molten core could interact with the reactor cavity region which consists of concrete. In this process, components of molten core react with components of concrete through a lot of chemical reactions. As a result, many kinds of gas species are generated and those move up forming rising bubbles into the reactor containment atmosphere. These rising bubbles are the carrier of the many kinds of the aerosols coming from the MCCI (Molten Core Concrete Interaction) layers. To evaluate the amount of the aerosols released from the MCCI layers, the amount of the gas species generated from those layers should be calculated. The chemical equilibrium state originally implies the final state of the multiple chemical reactions; therefore, investigating the equilibrium composition of molten core can be applicable to predict the gas generation status. The most common way for finding the chemical equilibrium state is a minimization of total Gibbs free energy of the system. In this paper, the method to make good guess of initial state is suggested and chemical reaction results are compared with results of CSSI report No 164. Total mass of system and the number of atoms of each element are conserved. The tendency of calculation results is similar with results presented in CSNI Report except a few species. These differences may be caused by absence of Gibbs energy data of the species such as Fe{sub 2}SiO{sub 4}, CaFe{sub 2}O{sub 4}, U(OH){sub 3}, UO(OH), UO{sub 2}(OH), U{sub 3}O{sub 7}, La, Ce.

Process Control Systems in the Chemical Industry: Safety vs. Security

Energy Technology Data Exchange (ETDEWEB)

Jeffrey Hahn; Thomas Anderson

2005-04-01

Traditionally, the primary focus of the chemical industry has been safety and productivity. However, recent threats to our nation’s critical infrastructure have prompted a tightening of security measures across many different industry sectors. Reducing vulnerabilities of control systems against physical and cyber attack is necessary to ensure the safety, security and effective functioning of these systems. The U.S. Department of Homeland Security has developed a strategy to secure these vulnerabilities. Crucial to this strategy is the Control Systems Security and Test Center (CSSTC) established to test and analyze control systems equipment. In addition, the CSSTC promotes a proactive, collaborative approach to increase industry's awareness of standards, products and processes that can enhance the security of control systems. This paper outlines measures that can be taken to enhance the cybersecurity of process control systems in the chemical sector.

ZnS nanoflakes deposition by modified chemical method

International Nuclear Information System (INIS)

Desai, Mangesh A.; Sartale, S. D.

2014-01-01

We report deposition of zinc sulfide nanoflakes on glass substrates by modified chemical method. The modified chemical method involves adsorption of zinc–thiourea complex on the substrate and its dissociation in presence of hydroxide ions to release sulfur ions from thiourea which react with zinc ions present in the complex to form zinc sulfide nanoflakes at room temperature. Influence of zinc salt and thiourea concentrations ratios on the morphology of the films was investigated by scanning electron microscope (SEM). The ratio of zinc and thiourea in the zinc–thiourea complex significantly affect the size of the zinc sulfide nanoflakes, especially width and density of the nanoflakes. The X-ray diffraction analysis exhibits polycrystalline nature of the zinc sulfide nanoflakes with hexagonal phase

MHD flow and heat transfer of a viscous reacting fluid over a ...

African Journals Online (AJOL)

This paper presents a boundary layer flow analysis for a viscous, incompressible, electrically conducting reacting fluid over a stretching sheet in the presence of a magnetic field. It is shown that the Hartmann, Prandtl and the Eckert numbers have effect on the velocity and temperature fields. Journal of the Nigerian ...

Performance of coils wound from long lengths of surface-coated, reacted, BSCCO-2212 conductor

Energy Technology Data Exchange (ETDEWEB)

Walker, M.S.; Hazelton, D.W.; Gardner, M.T. [Intermagnetics General Corp., Latham, NY (United States)] [and others

1996-10-01

React-before-wind surface-coated BSCCO-2212 is being established as a relatively low cost HTS conductor for practical applications. Quality tape is presently being manufactured in 450-500m lengths at a cost estimated to be 1/3-1/5 of the industry costs of BSCCO-2223 powder-in-tube tape. Robust, mechanically sound coils for applications ranging from NMR insert magnets to transformer windings are being made from this BSCCO-2212 tape. The coils have performed consistently through test and thermal cycling without degradation and as projected from short sample measurements. A hybrid approach, which uses mainly BSCCO- 2212 augmented by BSCCO-2223 conductor in the high radial field end regions, is expected to halve magnet system costs.

The assembly and use of continuous flow systems for chemical synthesis.

Science.gov (United States)

Britton, Joshua; Jamison, Timothy F

2017-11-01

The adoption of and opportunities in continuous flow synthesis ('flow chemistry') have increased significantly over the past several years. Continuous flow systems provide improved reaction safety and accelerated reaction kinetics, and have synthesised several active pharmaceutical ingredients in automated reconfigurable systems. Although continuous flow platforms are commercially available, systems constructed 'in-lab' provide researchers with a flexible, versatile, and cost-effective alternative. Herein, we describe the assembly and use of a modular continuous flow apparatus from readily available and affordable parts in as little as 30 min. Once assembled, the synthesis of a sulfonamide by reacting 4-chlorobenzenesulfonyl chloride with dibenzylamine in a single reactor coil with an in-line quench is presented. This example reaction offers the opportunity to learn several important skills including reactor construction, charging of a back-pressure regulator, assembly of stainless-steel syringes, assembly of a continuous flow system with multiple junctions, and yield determination. From our extensive experience of single-step and multistep continuous flow synthesis, we also describe solutions to commonly encountered technical problems such as precipitation of solids ('clogging') and reactor failure. Following this protocol, a nonspecialist can assemble a continuous flow system from reactor coils, syringes, pumps, in-line liquid-liquid separators, drying columns, back-pressure regulators, static mixers, and packed-bed reactors.

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

3D simulation of polyurethane foam injection and reacting mold flow in a complex geometry

Science.gov (United States)

Özdemir, İ. Bedii; Akar, Fırat

2018-05-01

The aim of the present work is to develop a flow model which can be used to determine the paths of the polyurethane foam in the mold filling process of a refrigerator cabinet so that improvements in the distribution and the size of the venting holes can be achieved without the expensive prototyping and experiments. For this purpose, the multi-component, two-phase chemically reacting flow is described by Navier Stokes and 12 scalar transport equations. The air and the multi-component foam zones are separated by an interface, which moves only with advection since the mass diffusion of species are set zero in the air zone. The inverse density, viscosity and other diffusion coefficients are calculated by a mass fraction weighted average of the corresponding temperature-dependent values of all species. Simulations are performed in a real refrigerator geometry, are able to reveal the problematical zones where air bubbles and voids trapped in the solidified foam are expected to occur. Furthermore, the approach proves itself as a reliable design tool to use in deciding the locations of air vents and sizing the channel dimensions.

Why Targets of Economic Sanctions React Differently: Reference Point Effects on North Korea and Libya

Directory of Open Access Journals (Sweden)

Jiyoun Park

2017-06-01

Full Text Available The international community has frequently introduced economic sanctions to curb the proliferation of weapons of mass destruction, to which each target nation has reacted differently. This paper explores the reasons why each target of economic sanctions reacts differently by specif- ically building a model based on reference point effects, and by analyzing the cases of North Korea and Libya. According to the results, when the reference point level increases, as in the case of North Korea, the target resists more firmly; on the other hand, when the reference point decreases, like in the case of Libya, the target resists more subtly.

The Responsive Environmental Assessment for Classroom Teaching (REACT): the dimensionality of student perceptions of the instructional environment.

Science.gov (United States)

Nelson, Peter M; Demers, Joseph A; Christ, Theodore J

2014-06-01

This study details the initial development of the Responsive Environmental Assessment for Classroom Teachers (REACT). REACT was developed as a questionnaire to evaluate student perceptions of the classroom teaching environment. Researchers engaged in an iterative process to develop, field test, and analyze student responses on 100 rating-scale items. Participants included 1,465 middle school students across 48 classrooms in the Midwest. Item analysis, including exploratory and confirmatory factor analysis, was used to refine a 27-item scale with a second-order factor structure. Results support the interpretation of a single general dimension of the Classroom Teaching Environment with 6 subscale dimensions: Positive Reinforcement, Instructional Presentation, Goal Setting, Differentiated Instruction, Formative Feedback, and Instructional Enjoyment. Applications of REACT in research and practice are discussed along with implications for future research and the development of classroom environment measures. PsycINFO Database Record (c) 2014 APA, all rights reserved.

Chemical cleaning the service water system at a nuclear power plant

International Nuclear Information System (INIS)

Brice, T.O.; Glover, W.A.

1994-01-01

Chemical cleaning a large cooling water system in a nuclear power plant presented many unique problems. The selection, qualification, and performance of the cleaning process were done using a phased approach. The piping was inspected to determine the extent of the problem. Deposit samples were removed from the service water system pipe and tested in the laboratory to determine the most effective cleaning solvent for deposit removal. An engineering study was performed to define the design parameters required to implement the system-wide chemical cleaning

Sticky tunes: how do people react to involuntary musical imagery?

Directory of Open Access Journals (Sweden)

Victoria J Williamson

Full Text Available The vast majority of people experience involuntary musical imagery (INMI or 'earworms'; perceptions of spontaneous, repetitive musical sound in the absence of an external source. The majority of INMI episodes are not bothersome, while some cause disruption ranging from distraction to anxiety and distress. To date, little is known about how the majority of people react to INMI, in particular whether evaluation of the experience impacts on chosen response behaviours or if attempts at controlling INMI are successful or not. The present study classified 1046 reports of how people react to INMI episodes. Two laboratories in Finland and the UK conducted an identical qualitative analysis protocol on reports of INMI reactions and derived visual descriptive models of the outcomes using grounded theory techniques. Combined analysis carried out across the two studies confirmed that many INMI episodes were considered neutral or pleasant, with passive acceptance and enjoyment being among the most popular response behaviours. A significant number of people, however, reported on attempts to cope with unwanted INMI. The most popular and effective behaviours in response to INMI were seeking out the tune in question, and musical or verbal distraction. The outcomes of this study contribute to our understanding of the aetiology of INMI, in particular within the framework of memory theory, and present testable hypotheses for future research on successful INMI coping strategies.

Sticky Tunes: How Do People React to Involuntary Musical Imagery?

Science.gov (United States)

Williamson, Victoria J.; Liikkanen, Lassi A.; Jakubowski, Kelly; Stewart, Lauren

2014-01-01

The vast majority of people experience involuntary musical imagery (INMI) or ‘earworms’; perceptions of spontaneous, repetitive musical sound in the absence of an external source. The majority of INMI episodes are not bothersome, while some cause disruption ranging from distraction to anxiety and distress. To date, little is known about how the majority of people react to INMI, in particular whether evaluation of the experience impacts on chosen response behaviours or if attempts at controlling INMI are successful or not. The present study classified 1046 reports of how people react to INMI episodes. Two laboratories in Finland and the UK conducted an identical qualitative analysis protocol on reports of INMI reactions and derived visual descriptive models of the outcomes using grounded theory techniques. Combined analysis carried out across the two studies confirmed that many INMI episodes were considered neutral or pleasant, with passive acceptance and enjoyment being among the most popular response behaviours. A significant number of people, however, reported on attempts to cope with unwanted INMI. The most popular and effective behaviours in response to INMI were seeking out the tune in question, and musical or verbal distraction. The outcomes of this study contribute to our understanding of the aetiology of INMI, in particular within the framework of memory theory, and present testable hypotheses for future research on successful INMI coping strategies. PMID:24497938

Chemical basis for minimal cognition

DEFF Research Database (Denmark)

Hanczyc, Martin; Ikegami, Takashi

tension between the drop of oil and its environment. We embed a chemical reaction in the oil phase that reacts with water when an oily precursor comes in contact with the water phase at the liquidliquid interface. This reaction not only powers the droplet to move in the aqueous phase but also allows...... for sustained movement. The direction of the movement is governed by a self-generated pH gradient that surrounds the droplet. In addition this self-generated gradient can be overridden by an externally imposed pH gradient, and therefore the direction of droplet motion may be controlled. Also we noticed...... that convection flow is generated inside the oil droplet to cause the movement, which was also confirmed by simulating the fluid dynamics integrated with chemical reactions (Matsuno et al., 2007, ACAL 07, Springer, p.179, Springer). We can observe that the droplet senses the gradient in the environment (either...

ENGINEERED BARRIER SYSTEM: PHYSICAL AND CHEMICAL ENVIRONMENT

International Nuclear Information System (INIS)

R. Jarek

2005-01-01

The purpose of this model report is to describe the evolution of the physical and chemical environmental conditions within the waste emplacement drifts of the repository, including the drip shield and waste package surfaces. The resulting seepage evaporation and gas abstraction models are used in the total system performance assessment for the license application (TSPA-LA) to assess the performance of the engineered barrier system and the waste form. This report develops and documents a set of abstraction-level models that describe the engineered barrier system physical and chemical environment. Where possible, these models use information directly from other reports as input, which promotes integration among process models used for TSPA-LA. Specific tasks and activities of modeling the physical and chemical environment are included in ''Technical Work Plan for: Near-Field Environment and Transport In-Drift Geochemistry Model Report Integration'' (BSC 2005 [DIRS 173782], Section 1.2.2). As described in the technical work plan, the development of this report is coordinated with the development of other engineered barrier system reports. To be consistent with other project documents that address features, events, and processes (FEPs), Table 6.14.1 of the current report includes updates to FEP numbers and FEP subjects for two FEPs identified in the technical work plan (TWP) governing this report (BSC 2005 [DIRS 173782]). FEP 2.1.09.06.0A (Reduction-oxidation potential in EBS), as listed in Table 2 of the TWP (BSC 2005 [DIRS 173782]), has been updated in the current report to FEP 2.1.09.06.0B (Reduction-oxidation potential in Drifts; see Table 6.14-1). FEP 2.1.09.07.0A (Reaction kinetics in EBS), as listed in Table 2 of the TWP (BSC 2005 [DIRS 173782]), has been updated in the current report to FEP 2.1.09.07.0B (Reaction kinetics in Drifts; see Table 6.14-1). These deviations from the TWP are justified because they improve integration with FEPs documents. The updates

Comparison of PDF and Moment Closure Methods in the Modeling of Turbulent Reacting Flows

Science.gov (United States)

Norris, Andrew T.; Hsu, Andrew T.

1994-01-01

In modeling turbulent reactive flows, Probability Density Function (PDF) methods have an advantage over the more traditional moment closure schemes in that the PDF formulation treats the chemical reaction source terms exactly, while moment closure methods are required to model the mean reaction rate. The common model used is the laminar chemistry approximation, where the effects of turbulence on the reaction are assumed negligible. For flows with low turbulence levels and fast chemistry, the difference between the two methods can be expected to be small. However for flows with finite rate chemistry and high turbulence levels, significant errors can be expected in the moment closure method. In this paper, the ability of the PDF method and the moment closure scheme to accurately model a turbulent reacting flow is tested. To accomplish this, both schemes were used to model a CO/H2/N2- air piloted diffusion flame near extinction. Identical thermochemistry, turbulence models, initial conditions and boundary conditions are employed to ensure a consistent comparison can be made. The results of the two methods are compared to experimental data as well as to each other. The comparison reveals that the PDF method provides good agreement with the experimental data, while the moment closure scheme incorrectly shows a broad, laminar-like flame structure.

SQL Triggers Reacting on Time Events: An Extension Proposal

Science.gov (United States)

Behrend, Andreas; Dorau, Christian; Manthey, Rainer

Being able to activate triggers at timepoints reached or after time intervals elapsed has been acknowledged by many authors as a valuable functionality of a DBMS. Recently, the interest in time-based triggers has been renewed in the context of data stream monitoring. However, up till now SQL triggers react to data changes only, even though research proposals and prototypes have been supporting several other event types, in particular time-based ones, since long. We therefore propose a seamless extension of the SQL trigger concept by time-based triggers, focussing on semantic issues arising from such an extension.

Methane reacts with heteropolyacids chemisorbed on silica to produce acetic acid under soft conditions

KAUST Repository

Sun, Miao; Abou-Hamad, Edy; Rossini, Aaron J.; Zhang, Jizhe; Lesage, Anne; Zhu, Haibo; Pelletier, Jeremie; Emsley, Lyndon; Caps, Valerie; Basset, Jean-Marie

2013-01-01

Selective functionalization of methane at moderate temperature is of crucial economic, environmental, and scientific importance. Here, we report that methane reacts with heteropolyacids (HPAs) chemisorbed on silica to produce acetic acid under soft

Sistema RTP: uma técnica poderosa para o monitoramento da formação de nanotubos de carbono durante o processo por deposição de vapor químico TPR system: a powerful technique to monitor carbon nanotube formation during chemical vapour deposition

Directory of Open Access Journals (Sweden)

Juliana Cristina Tristão

2010-01-01

Full Text Available In this work, a TPR (Temperature Programmed Reduction system is used as a powerful tool to monitor carbon nanotubes production during CVD (Chemical Vapour Deposition, The experiments were carried out using catalyst precursors based on Fe-Mo supported on Al2O3 and methane as carbon source. As methane reacts on the Fe metal surface, carbon is deposited and H2 is produced. TPR is very sensitive to the presence of H2 and affords information on the temperature where catalyst is active to form different forms of carbon, the reaction kinetics, the catalyst deactivation and carbon yields.

A multi-attribute Systemic Risk Index for comparing and prioritizing chemical industrial areas

International Nuclear Information System (INIS)

Reniers, G.L.L.; Sörensen, K.; Dullaert, W.

2012-01-01

Measures taken to decrease interdependent risks within chemical industrial areas should be based on quantitative data from a holistic (cluster-based) point of view. Therefore, this paper examines the typology of networks representing industrial areas to formulate recommendations to more effectively protect a chemical cluster against existing systemic risks. Chemical industrial areas are modeled as two distinct complex networks and are prioritized by computing two sub-indices with respect to existing systemic safety and security risks (using Domino Danger Units) and supply chain risks (using units from an ordinal expert scale). Subsequently, a Systemic Risk Index for the industrial area is determined employing the Borda algorithm, whereby the systemic risk index considers both a safety and security network risk index and a supply chain network risk index. The developed method allows decreasing systemic risks within chemical industrial areas from a holistic (inter-organizational and/or inter-cluster) perspective. An illustrative example is given.

Process for carrying out a chemical reaction with ionic liquid and carbon dioxide under pressure

NARCIS (Netherlands)

Kroon, M.C.; Shariati, A.; Florusse, L.J.; Peters, C.J.; Van Spronsen, J.; Witkamp, G.J.; Sheldon, R.A.; Gutkowski, K.I.

2006-01-01

The invention is directed to a process for carrying out a chemical reaction in an ionic liquid as solvent and CO2 as cosolvent, in which process reactants are reacted in a homogeneous phase at selected pressure and temperature to generate a reaction product at least containing an end-product of the

Temporal cross-correlation asymmetry and departure from equilibrium in a bistable chemical system.

Science.gov (United States)

Bianca, C; Lemarchand, A

2014-06-14

This paper aims at determining sustained reaction fluxes in a nonlinear chemical system driven in a nonequilibrium steady state. The method relies on the computation of cross-correlation functions for the internal fluctuations of chemical species concentrations. By employing Langevin-type equations, we derive approximate analytical formulas for the cross-correlation functions associated with nonlinear dynamics. Kinetic Monte Carlo simulations of the chemical master equation are performed in order to check the validity of the Langevin equations for a bistable chemical system. The two approaches are found in excellent agreement, except for critical parameter values where the bifurcation between monostability and bistability occurs. From the theoretical point of view, the results imply that the behavior of cross-correlation functions cannot be exploited to measure sustained reaction fluxes in a specific nonlinear system without the prior knowledge of the associated chemical mechanism and the rate constants.

Development of a Mechanical Analysis System Considering Chemical Transitions of Barrier Materials

International Nuclear Information System (INIS)

Sahara, F.; Murakami, T.; Ito, H.; Kobayashi, I.; Yokozeki, K.

2006-01-01

An analysis system for the long-term mechanical behavior of barrier materials (MACBECE: Mechanical Analysis system considering Chemical transitions of Bentonite-based and Cement-based materials) was developed in order to improve the reliability of the evaluation of the hydraulic field that is one of the important environmental conditions in the safety assessment of the TRU waste disposal in Japan. The MACBECE is a system that calculates the deformation of barrier materials using their chemical property changes as inputs, and subsequently their hydraulic conductivity taking both their chemical property changes and deformation into consideration. This paper provides a general description of MACBECE and the results of experimental analysis carried out using MACBECE. (authors)

Chemical Engineering Education in a Bologna Three Cycle Degree System

DEFF Research Database (Denmark)

Gani, Rafiqul

For the purpose of harmonization of European higher education, Europe’s education system has been going through major changes under what is commonly known as the ”Bologna Process”. The Bologna declaration in 1999 was the start of the introduction of a three cycle degree system in higher education...... in Europe. To date, many European universities have adopted this degree structure. The Working Party on Education (WPE) of the European Federation of Chemical Engineering (EFCE) carried out research to determine the contents of higher education in chemical engineering (ChE) and related disciplines...... such as applied chemistry and process engineering throughout Europe. The result has been a set of recommendations for the first (BS), second (MS) and third (PhD) cycle chemical engineering education aligned to the Bologna Process. They recommend that students studying towards bachelor and masters qualifications...

LES-ODT Simulations of Turbulent Reacting Shear Layers

Science.gov (United States)

Hoffie, Andreas; Echekki, Tarek

2012-11-01

Large-eddy simulations (LES) combined with the one-dimensional turbulence (ODT) simulations of a spatially developing turbulent reacting shear layer with heat release and high Reynolds numbers were conducted and compared to results from direct numerical simulations (DNS) of the same configuration. The LES-ODT approach is based on LES solutions for momentum on a coarse grid and solutions for momentum and reactive scalars on a fine ODT grid, which is embedded in the LES computational domain. The shear layer is simulated with a single-step, second-order reaction with an Arrhenius reaction rate. The transport equations are solved using a low Mach number approximation. The LES-ODT simulations yield reasonably accurate predictions of turbulence and passive/reactive scalars' statistics compared to DNS results.

Detecting and Reacting to Change: The Effect of Exposure to Narrow Categorizations

Science.gov (United States)

Chakravarti, Amitav; Fang, Christina; Shapira, Zur

2011-01-01

The ability to detect a change, to accurately assess the magnitude of the change, and to react to that change in a commensurate fashion are of critical importance in many decision domains. Thus, it is important to understand the factors that systematically affect people's reactions to change. In this article we document a novel effect: Decision…

Iteration scheme for implicit calculations of kinetic and equilibrium chemical reactions in fluid dynamics

International Nuclear Information System (INIS)

Ramshaw, J.D.; Chang, C.H.

1995-01-01

An iteration scheme for the implicit treatment of equilibrium chemical reactions in partial equilibrium flow has previously been described. Here we generalize this scheme to kinetic reactions as well as equilibrium reactions. This extends the applicability of the scheme to problems with kinetic reactions that are fast in regions of the flow field but slow in others. The resulting scheme thereby provides a single unified framework for the implicit treatment of an arbitrary number of coupled equilibrium and kinetic reactions in chemically reacting fluid flow. 10 refs., 2 figs

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

The development of the globally harmonized system (GHS) of classification and labelling of hazardous chemicals

International Nuclear Information System (INIS)

Winder, Chris; Azzi, Rola; Wagner, Drew

2005-01-01

The hazards of chemicals can be classified using classification criteria that are based on physical, chemical and ecotoxicological endpoints. These criteria may be developed be iteratively, based on scientific or regulatory processes. A number of national and international schemes have been developed over the past 50 years, and some, such as the UN Dangerous Goods system or the EC system for hazardous substances, are in widespread use. However, the unnecessarily complicated multiplicity of existing hazard classifications created much unnecessary confusion at the user level, and a recommendation was made at the 1992 Rio Earth summit to develop a globally harmonized chemical hazard classification and compatible labelling system, including material safety data sheets and easily understandable symbols, that could be used for manufacture, transport, use and disposal of chemical substances. This became the globally harmonized system for the Classification and Labelling of Chemicals (GHS). The developmental phase of the GHS is largely complete. Consistent criteria for categorising chemicals according to their toxic, physical, chemical and ecological hazards are now available. Consistent hazard communication tools such as labelling and material safety data sheets are also close to finalisation. The next phase is implementation of the GHS. The Intergovernmental Forum for Chemical Safety recommends that all countries implement the GHS as soon as possible with a view to have the system fully operational by 2008. When the GHS is in place, the world will finally have one system for classification of chemical hazards

Roadmap for a Smart Factory: A Modular, Intelligent Concept for the Production of Specialty Chemicals.

Science.gov (United States)

Reitze, Arnulf; Jürgensmeyer, Nikolas; Lier, Stefan; Kohnke, Marco; Riese, Julia; Grünewald, Marcus

2018-04-09

Digitalization and increasing the flexibility of production concepts offer the possibility to react to market challenges in the field of specialty chemicals. Shorter product lifetimes, increasing product individualization, and the resulting market volatility impose new requirements on plant operators. Novel concepts such as modular production plants and developments in digitalization (Industry 4.0) are able to assist the implementation of smart factories in specialty chemicals. These essential concepts will be presented in this Minireview. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Comparing Spray Characteristics from Reynolds Averaged Navier-Stokes (RANS) National Combustion Code (NCC) Calculations Against Experimental Data for a Turbulent Reacting Flow

Science.gov (United States)

Iannetti, Anthony C.; Moder, Jeffery P.

2010-01-01

Developing physics-based tools to aid in reducing harmful combustion emissions, like Nitrogen Oxides (NOx), Carbon Monoxide (CO), Unburnt Hydrocarbons (UHC s), and Sulfur Dioxides (SOx), is an important goal of aeronautics research at NASA. As part of that effort, NASA Glenn Research Center is performing a detailed assessment and validation of an in-house combustion CFD code known as the National Combustion Code (NCC) for turbulent reacting flows. To assess the current capabilities of NCC for simulating turbulent reacting flows with liquid jet fuel injection, a set of Single Swirler Lean Direct Injection (LDI) experiments performed at the University of Cincinnati was chosen as an initial validation data set. This Jet-A/air combustion experiment operates at a lean equivalence ratio of 0.75 at atmospheric pressure and has a 4 percent static pressure drop across the swirler. Detailed comparisons of NCC predictions for gas temperature and gaseous emissions (CO and NOx) against this experiment are considered in a previous work. The current paper is focused on detailed comparisons of the spray characteristics (radial profiles of drop size distribution and at several radial rakes) from NCC simulations against the experimental data. Comparisons against experimental data show that the use of the correlation for primary spray break-up implemented by Raju in the NCC produces most realistic results, but this result needs to be improved. Given the single or ten step chemical kinetics models, use of a spray size correlation gives similar, acceptable results

Construction of a risk assessment system for chemical residues in agricultural products.

Science.gov (United States)

Choi, Shinai; Hong, Jiyeon; Lee, Dayeon; Paik, Minkyoung

2014-01-01

Continuous monitoring of chemical residues in agricultural and food products has been performed by various government bodies in South Korea. These bodies have made attempts to systematically manage this information by creating a monitoring database system as well as a system based on these data with which to assess the health risk of chemical residues in agricultural products. Meanwhile, a database system is being constructed consisting of information about monitoring and, following this, a demand for convenience has led to the need for an evaluation tool to be constructed with the data processing system. Also, in order to create a systematic and effective tool for the risk assessment of chemical residues in foods and agricultural products, various evaluation models are being developed, both domestically and abroad. Overseas, systems such as Dietary Exposure Evaluation Model: Food Commodity Intake Database and Cumulative and Aggregate Risk Evaluation System are being used; these use the US Environmental Protection Agency as a focus, while the EU has developed Pesticide Residue Intake Model for assessments of pesticide exposure through food intake. Following this, the National Academy of Agricultural Science (NAAS) created the Agricultural Products Risk Assessment System (APRAS) which supports the use and storage of monitoring information and risk assessments. APRAS efficiently manages the monitoring data produced by NAAS and creates an extraction feature included in the database system. Also, the database system in APRAS consists of a monitoring database system held by the NAAS and food consumption database system. Food consumption data is based on Korea National Health and Nutrition Examination Survey. This system is aimed at exposure and risk assessments for chemical residues in agricultural products with regards to different exposure scenarios.

Some Sensitivity Studies of Chemical Transport Simulated in Models of the Soil-Plant-Litter System

Energy Technology Data Exchange (ETDEWEB)

Begovich, C.L.

2002-10-28

Fifteen parameters in a set of five coupled models describing carbon, water, and chemical dynamics in the soil-plant-litter system were varied in a sensitivity analysis of model response. Results are presented for chemical distribution in the components of soil, plants, and litter along with selected responses of biomass, internal chemical transport (xylem and phloem pathways), and chemical uptake. Response and sensitivity coefficients are presented for up to 102 model outputs in an appendix. Two soil properties (chemical distribution coefficient and chemical solubility) and three plant properties (leaf chemical permeability, cuticle thickness, and root chemical conductivity) had the greatest influence on chemical transport in the soil-plant-litter system under the conditions examined. Pollutant gas uptake (SO{sub 2}) increased with change in plant properties that increased plant growth. Heavy metal dynamics in litter responded to plant properties (phloem resistance, respiration characteristics) which induced changes in the chemical cycling to the litter system. Some of the SO{sub 2} and heavy metal responses were not expected but became apparent through the modeling analysis.

A rapid method for the computation of equilibrium chemical composition of air to 15000 K

Science.gov (United States)

Prabhu, Ramadas K.; Erickson, Wayne D.

1988-01-01

A rapid computational method has been developed to determine the chemical composition of equilibrium air to 15000 K. Eleven chemically reacting species, i.e., O2, N2, O, NO, N, NO+, e-, N+, O+, Ar, and Ar+ are included. The method involves combining algebraically seven nonlinear equilibrium equations and four linear elemental mass balance and charge neutrality equations. Computational speeds for determining the equilibrium chemical composition are significantly faster than the often used free energy minimization procedure. Data are also included from which the thermodynamic properties of air can be computed. A listing of the computer program together with a set of sample results are included.

Electronic dissipation processes during chemical reactions on surfaces

CERN Document Server

Stella, Kevin

2012-01-01

Hauptbeschreibung Every day in our life is larded with a huge number of chemical reactions on surfaces. Some reactions occur immediately, for others an activation energy has to be supplied. Thus it happens that though a reaction should thermodynamically run off, it is kinetically hindered. Meaning the partners react only to the thermodynamically more stable product state within a mentionable time if the activation energy of the reaction is supplied. With the help of catalysts the activation energy of a reaction can be lowered. Such catalytic processes on surfaces are widely used in industry. A

Numerical solution of stiff systems of ordinary differential equations with applications to electronic circuits

Science.gov (United States)

Rosenbaum, J. S.

1971-01-01

Systems of ordinary differential equations in which the magnitudes of the eigenvalues (or time constants) vary greatly are commonly called stiff. Such systems of equations arise in nuclear reactor kinetics, the flow of chemically reacting gas, dynamics, control theory, circuit analysis and other fields. The research reported develops an A-stable numerical integration technique for solving stiff systems of ordinary differential equations. The method, which is called the generalized trapezoidal rule, is a modification of the trapezoidal rule. However, the method is computationally more efficient than the trapezoidal rule when the solution of the almost-discontinuous segments is being calculated.

Development of techniques for tagging precursor and essential chemicals

Energy Technology Data Exchange (ETDEWEB)

Swansiger, W.A.; Shepodd, T.J. [Sandia National Labs., Livermore, CA (United States); Phillips, M.L.F. [Sandia National Labs., Albuquerque, NM (United States)

1994-01-01

The ability to identify the manufacturers and distributors of chemicals seized in raids of illicit drug labs would be of great value in controlling the diversion of these chemicals. We developed a tagging scheme based on the addition of sub-ppM concentrations of various combinations of rare-earth elements to the target chemicals and evaluated a number of techniques for detecting the tags. We developed soluble tags for tagging liquids and selected Inductively Coupled Plasma-Mass Spectrometry (ICP-MS) as the preferred detection technique. We developed insoluble tags for tagging solids and developed methods to analyze them and mix them into solid precursors. We have successfully demonstrated the tagging of several solvents and two of the precursor chemicals used in one of the most popular clandestine methamphetamine syntheses (ephedrine reacting with hydriodic acid/red phosphorus). The tagging scheme is capable of yielding tens of thousands of signatures (using holmium as an internal standard and up to 9 rare-earths at up to 3 concentrations yields 3{sup 9} {minus} 1 = 19,682 signatures) and is applicable to most of the chemicals on the precursor and essential chemicals list. In the concentrations employed, the tags are safe enough to be added to pharmaceuticals and cheap enough to tag tanker loads of chemicals.

Numerical Investigation into CO Emission, O Depletion, and Thermal Decomposition in a Reacting Slab

Directory of Open Access Journals (Sweden)

O. D. Makinde

2011-01-01

Full Text Available The emission of carbon dioxide (CO2 is closely associated with oxygen (O2 depletion, and thermal decomposition in a reacting stockpile of combustible materials like fossil fuels (e.g., coal, oil, and natural gas. Moreover, it is understood that proper assessment of the emission levels provides a crucial reference point for other assessment tools like climate change indicators and mitigation strategies. In this paper, a nonlinear mathematical model for estimating the CO2 emission, O2 depletion, and thermal stability of a reacting slab is presented and tackled numerically using a semi-implicit finite-difference scheme. It is assumed that the slab surface is subjected to a symmetrical convective heat and mass exchange with the ambient. Both numerical and graphical results are presented and discussed quantitatively with respect to various parameters embedded in the problem.

On mathematical modeling and numerical simulation of chemical kinetics in turbulent lean premixed combustion

Energy Technology Data Exchange (ETDEWEB)

Lilleberg, Bjorn

2011-07-01

This thesis investigates turbulent reacting lean premixed flows with detailed treatment of the chemistry. First, the fundamental equations which govern laminar and turbulent reacting flows are presented. A perfectly stirred reactor numerical code is developed to investigate the role of unmixedness and chemical kinetics in driving combustion instabilities. This includes both global single-step and detailed chemical kinetic mechanisms. The single-step mechanisms predict to some degree a similar behavior as the detailed mechanisms. However, it is shown that simple mechanisms can by themselves introduce instabilities. Magnussens Eddy Dissipation Concept (EDC) for turbulent combustion is implemented in the open source CFD toolbox OpenFOAM R for treatment of both fast and detailed chemistry. RANS turbulence models account for the turbulent compressible flow. A database of pre-calculated chemical time scales, which contains the influence of chemical kinetics, is coupled to EDC with fast chemistry to account for local extinction in both diffusion and premixed flames. Results are compared to fast and detailed chemistry calculations. The inclusion of the database shows significantly better results than the fast chemistry calculations while having a comparably small computational cost. Numerical simulations of four piloted lean premixed jet flames falling into the 'well stirred reactor/broken reaction zones' regime, with strong finite-rate chemistry effects, are performed. Measured and predicted scalars compare well for the two jets with the lowest velocities. The two jets with the highest velocities experience extinction and reignition, and the simulations are able to capture the decrease and increase of the OH mass fractions, but the peak values are higher than in the experiments. Also numerical simulations of a lean premixed lifted jet flame with high sensitivity to turbulence modeling and chemical kinetics are performed. Limitations of the applied turbulence and

Customizable Generation of Synthetically Accessible, Local Chemical Subspaces.

Science.gov (United States)

Pottel, Joshua; Moitessier, Nicolas

2017-03-27

Screening large libraries of chemicals has been an efficient strategy to discover bioactive compounds; however a portion of the potential for success is limited to the available libraries. Synergizing combinatorial and computational chemistries has emerged as a time-efficient strategy to explore the chemical space more widely. Ideally, streamlining the evaluation process for larger, feasible chemical libraries would become commonplace. Thus, combinatorial tools and, for example, docking methods would be integrated to identify novel bioactive entities. The idea is simple in nature, but much more complex in practice; combinatorial chemistry is more than the coupling of chemicals into products: synthetic feasibility includes chemoselectivity, stereoselectivity, protecting group chemistry, and chemical availability which must all be considered for combinatorial library design. In addition, intuitive interfaces and simple user manipulation is key for optimal use of such tools by organic chemists-crucial for the integration of such software in medicinal chemistry laboratories. We present herein Finders and React2D-integrated into the Virtual Chemist platform, a modular software suite. This approach enhances virtual combinatorial chemistry by identifying available chemicals compatible with a user-defined chemical transformation and by carrying out the reaction leading to libraries of realistic, synthetically accessible chemicals-all with a completely automated, black-box, and efficient design. We demonstrate its utility by generating ∼40 million synthetically accessible, stereochemically accurate compounds from a single library of 100 000 purchasable molecules and 56 well-characterized chemical reactions.

Cellular automaton model of mass transport with chemical reactions

International Nuclear Information System (INIS)

Karapiperis, T.; Blankleider, B.

1993-10-01

The transport and chemical reactions of solutes are modelled as a cellular automaton in which molecules of different species perform a random walk on a regular lattice and react according to a local probabilistic rule. The model describes advection and diffusion in a simple way, and as no restriction is placed on the number of particles at a lattice site, it is also able to describe a wide variety of chemical reactions. Assuming molecular chaos and a smooth density function, we obtain the standard reaction-transport equations in the continuum limit. Simulations on one-and two-dimensional lattices show that the discrete model can be used to approximate the solutions of the continuum equations. We discuss discrepancies which arise from correlations between molecules and how these discrepancies disappear as the continuum limit is approached. Of particular interest are simulations displaying long-time behaviour which depends on long-wavelength statistical fluctuations not accounted for by the standard equations. The model is applied to the reactions a + b ↔ c and a + b → c with homogeneous and inhomogeneous initial conditions as well as to systems subject to autocatalytic reactions and displaying spontaneous formation of spatial concentration patterns. (author) 9 figs., 34 refs

Chemical Sensor Systems and Associated Algorithms for Fire Detection: A Review

Directory of Open Access Journals (Sweden)

Jordi Fonollosa

2018-02-01

Full Text Available Indoor fire detection using gas chemical sensing has been a subject of investigation since the early nineties. This approach leverages the fact that, for certain types of fire, chemical volatiles appear before smoke particles do. Hence, systems based on chemical sensing can provide faster fire alarm responses than conventional smoke-based fire detectors. Moreover, since it is known that most casualties in fires are produced from toxic emissions rather than actual burns, gas-based fire detection could provide an additional level of safety to building occupants. In this line, since the 2000s, electrochemical cells for carbon monoxide sensing have been incorporated into fire detectors. Even systems relying exclusively on gas sensors have been explored as fire detectors. However, gas sensors respond to a large variety of volatiles beyond combustion products. As a result, chemical-based fire detectors require multivariate data processing techniques to ensure high sensitivity to fires and false alarm immunity. In this paper, we the survey toxic emissions produced in fires and defined standards for fire detection systems. We also review the state of the art of chemical sensor systems for fire detection and the associated signal and data processing algorithms. We also examine the experimental protocols used for the validation of the different approaches, as the complexity of the test measurements also impacts on reported sensitivity and specificity measures. All in all, further research and extensive test under different fire and nuisance scenarios are still required before gas-based fire detectors penetrate largely into the market. Nevertheless, the use of dynamic features and multivariate models that exploit sensor correlations seems imperative.

Chemical Sensor Systems and Associated Algorithms for Fire Detection: A Review.

Science.gov (United States)

Fonollosa, Jordi; Solórzano, Ana; Marco, Santiago

2018-02-11

Indoor fire detection using gas chemical sensing has been a subject of investigation since the early nineties. This approach leverages the fact that, for certain types of fire, chemical volatiles appear before smoke particles do. Hence, systems based on chemical sensing can provide faster fire alarm responses than conventional smoke-based fire detectors. Moreover, since it is known that most casualties in fires are produced from toxic emissions rather than actual burns, gas-based fire detection could provide an additional level of safety to building occupants. In this line, since the 2000s, electrochemical cells for carbon monoxide sensing have been incorporated into fire detectors. Even systems relying exclusively on gas sensors have been explored as fire detectors. However, gas sensors respond to a large variety of volatiles beyond combustion products. As a result, chemical-based fire detectors require multivariate data processing techniques to ensure high sensitivity to fires and false alarm immunity. In this paper, we the survey toxic emissions produced in fires and defined standards for fire detection systems. We also review the state of the art of chemical sensor systems for fire detection and the associated signal and data processing algorithms. We also examine the experimental protocols used for the validation of the different approaches, as the complexity of the test measurements also impacts on reported sensitivity and specificity measures. All in all, further research and extensive test under different fire and nuisance scenarios are still required before gas-based fire detectors penetrate largely into the market. Nevertheless, the use of dynamic features and multivariate models that exploit sensor correlations seems imperative.

Chemical Sensor Systems and Associated Algorithms for Fire Detection: A Review

Science.gov (United States)

Fonollosa, Jordi

2018-01-01

Indoor fire detection using gas chemical sensing has been a subject of investigation since the early nineties. This approach leverages the fact that, for certain types of fire, chemical volatiles appear before smoke particles do. Hence, systems based on chemical sensing can provide faster fire alarm responses than conventional smoke-based fire detectors. Moreover, since it is known that most casualties in fires are produced from toxic emissions rather than actual burns, gas-based fire detection could provide an additional level of safety to building occupants. In this line, since the 2000s, electrochemical cells for carbon monoxide sensing have been incorporated into fire detectors. Even systems relying exclusively on gas sensors have been explored as fire detectors. However, gas sensors respond to a large variety of volatiles beyond combustion products. As a result, chemical-based fire detectors require multivariate data processing techniques to ensure high sensitivity to fires and false alarm immunity. In this paper, we the survey toxic emissions produced in fires and defined standards for fire detection systems. We also review the state of the art of chemical sensor systems for fire detection and the associated signal and data processing algorithms. We also examine the experimental protocols used for the validation of the different approaches, as the complexity of the test measurements also impacts on reported sensitivity and specificity measures. All in all, further research and extensive test under different fire and nuisance scenarios are still required before gas-based fire detectors penetrate largely into the market. Nevertheless, the use of dynamic features and multivariate models that exploit sensor correlations seems imperative. PMID:29439490

ENGINEERED BARRIER SYSTEM: PHYSICAL AND CHEMICAL ENVIRONMENT

Energy Technology Data Exchange (ETDEWEB)

R. Jarek

2005-08-29

The purpose of this model report is to describe the evolution of the physical and chemical environmental conditions within the waste emplacement drifts of the repository, including the drip shield and waste package surfaces. The resulting seepage evaporation and gas abstraction models are used in the total system performance assessment for the license application (TSPA-LA) to assess the performance of the engineered barrier system and the waste form. This report develops and documents a set of abstraction-level models that describe the engineered barrier system physical and chemical environment. Where possible, these models use information directly from other reports as input, which promotes integration among process models used for TSPA-LA. Specific tasks and activities of modeling the physical and chemical environment are included in ''Technical Work Plan for: Near-Field Environment and Transport In-Drift Geochemistry Model Report Integration'' (BSC 2005 [DIRS 173782], Section 1.2.2). As described in the technical work plan, the development of this report is coordinated with the development of other engineered barrier system reports. To be consistent with other project documents that address features, events, and processes (FEPs), Table 6.14.1 of the current report includes updates to FEP numbers and FEP subjects for two FEPs identified in the technical work plan (TWP) governing this report (BSC 2005 [DIRS 173782]). FEP 2.1.09.06.0A (Reduction-oxidation potential in EBS), as listed in Table 2 of the TWP (BSC 2005 [DIRS 173782]), has been updated in the current report to FEP 2.1.09.06.0B (Reduction-oxidation potential in Drifts; see Table 6.14-1). FEP 2.1.09.07.0A (Reaction kinetics in EBS), as listed in Table 2 of the TWP (BSC 2005 [DIRS 173782]), has been updated in the current report to FEP 2.1.09.07.0B (Reaction kinetics in Drifts; see Table 6.14-1). These deviations from the TWP are justified because they improve integration with FEPs

A survey of chemicals inducing lipid peroxidation in biological systems.

Science.gov (United States)

Kappus, H

1987-01-01

A great number of drugs and chemicals are reviewed which have been shown to stimulate lipid peroxidation in any biological system. The underlying mechanisms, as far as known, are also dealt with. Lipid peroxidation induced by iron ions, organic hydroperoxides, halogenated hydrocarbons, redox cycling drugs, glutathione depleting chemicals, ethanol, heavy metals, ozone, nitrogen dioxide and a number of miscellaneous compounds, e.g. hydrazines, pesticides, antibiotics, are mentioned. It is shown that lipid peroxidation is stimulated by many of these compounds. However, quantitative estimates cannot be given yet and it is still impossible to judge the biological relevance of chemical-induced lipid peroxidation.

Assessing the chemical contamination dynamics in a mixed land use stream system

DEFF Research Database (Denmark)

Sonne, Anne Thobo; McKnight, Ursula S.; Rønde, Vinni

2017-01-01

Traditionally, the monitoring of streams for chemical and ecological status has been limited to surface water concentrations, where the dominant focus has been on general water quality and the risk for eutrophication. Mixed land use stream systems, comprising urban areas and agricultural production......, are challenging to assess with multiple chemical stressors impacting stream corridors. New approaches are urgently needed for identifying relevant sources, pathways and potential impacts for implementation of suitable source management and remedial measures. We developed a method for risk assessing chemical...... stressors in these systems and applied the approach to a 16-km groundwater-fed stream corridor (Grindsted, Denmark). Three methods were combined: (i) in-stream contaminant mass discharge for source quantification, (ii) Toxic Units and (iii) environmental standards. An evaluation of the chemical quality...

Characterizing chemical systems with on-line computers and graphics

International Nuclear Information System (INIS)

Frazer, J.W.; Rigdon, L.P.; Brand, H.R.; Pomernacki, C.L.

1979-01-01

Incorporating computers and graphics on-line to chemical experiments and processes opens up new opportunities for the study and control of complex systems. Systems having many variables can be characterized even when the variable interactions are nonlinear, and the system cannot a priori be represented by numerical methods and models. That is, large sets of accurate data can be rapidly acquired, then modeling and graphic techniques can be used to obtain partial interpretation plus design of further experimentation. The experimenter can thus comparatively quickly iterate between experimentation and modeling to obtain a final solution. We have designed and characterized a versatile computer-controlled apparatus for chemical research, which incorporates on-line instrumentation and graphics. It can be used to determine the mechanism of enzyme-induced reactions or to optimize analytical methods. The apparatus can also be operated as a pilot plant to design control strategies. On-line graphics were used to display conventional plots used by biochemists and three-dimensional response-surface plots

A chemically inert drug can stimulate T cells in vitro by their T cell receptor in non-sensitised individuals

International Nuclear Information System (INIS)

Engler, Olivier B.; Strasser, Ingrid; Naisbitt, Dean J.; Cerny, Andreas; Pichler, Werner J.

2004-01-01

Drugs can interact with T cell receptors (TCR) after binding to peptide-MHC structures. This binding may involve the formation of a stable, covalent bond between a chemically reactive drug and MHC or the peptide embedded within. Alternatively, if the drug is chemically inert, the binding may be non-covalent and readily reversible. Both types of drug presentation account for a substantial number of adverse side effects to drugs. Presently no tests are available to predict the ability of chemically inert drugs to stimulate an immune response. Here we present data on the successful induction of a primary T cell immune response in vitro against a chemically inert drug using blood from healthy individuals, previously not exposed to the drug. Blood lymphocytes were stimulated by the chemically inert drug sulfamethoxazole and the protein-reactive drug-metabolite sulfamethoxazole-nitroso in the presence of IL-2. 9/10 individuals reacted in response to sulfamethoxazole-nitroso, but only three reacted to the chemically inert compound sulfamethoxazole. Drug reactive T cells could be detected after 14-35 days of cell culture by drug-specific proliferation or cytotoxicity, which was MHC-restricted. These cells were CD4, CD8 positive or CD4/CD8 double positive and T cell clones generated secreted Th0 type cytokines. Drug interaction lead to down-regulation of specific TCR. These data confirm the ability of chemically inert drugs to stimulate certain T cells by their TCR and may provide the opportunity to screen new drugs for their ability to interact with TCRs

Building an R&D chemical registration system.

Science.gov (United States)

Martin, Elyette; Monge, Aurélien; Duret, Jacques-Antoine; Gualandi, Federico; Peitsch, Manuel C; Pospisil, Pavel

2012-05-31

Small molecule chemistry is of central importance to a number of R&D companies in diverse areas such as the pharmaceutical, nutraceutical, food flavoring, and cosmeceutical industries. In order to store and manage thousands of chemical compounds in such an environment, we have built a state-of-the-art master chemical database with unique structure identifiers. Here, we present the concept and methodology we used to build the system that we call the Unique Compound Database (UCD). In the UCD, each molecule is registered only once (uniqueness), structures with alternative representations are entered in a uniform way (normalization), and the chemical structure drawings are recognizable to chemists and to a cartridge. In brief, structural molecules are entered as neutral entities which can be associated with a salt. The salts are listed in a dictionary and bound to the molecule with the appropriate stoichiometric coefficient in an entity called "substance". The substances are associated with batches. Once a molecule is registered, some properties (e.g., ADMET prediction, IUPAC name, chemical properties) are calculated automatically. The UCD has both automated and manual data controls. Moreover, the UCD concept enables the management of user errors in the structure entry by reassigning or archiving the batches. It also allows updating of the records to include newly discovered properties of individual structures. As our research spans a wide variety of scientific fields, the database enables registration of mixtures of compounds, enantiomers, tautomers, and compounds with unknown stereochemistries.

Building an R&D chemical registration system

Directory of Open Access Journals (Sweden)

Martin Elyette

2012-05-01

Full Text Available Abstract Small molecule chemistry is of central importance to a number of R&D companies in diverse areas such as the pharmaceutical, nutraceutical, food flavoring, and cosmeceutical industries. In order to store and manage thousands of chemical compounds in such an environment, we have built a state-of-the-art master chemical database with unique structure identifiers. Here, we present the concept and methodology we used to build the system that we call the Unique Compound Database (UCD. In the UCD, each molecule is registered only once (uniqueness, structures with alternative representations are entered in a uniform way (normalization, and the chemical structure drawings are recognizable to chemists and to a cartridge. In brief, structural molecules are entered as neutral entities which can be associated with a salt. The salts are listed in a dictionary and bound to the molecule with the appropriate stoichiometric coefficient in an entity called “substance”. The substances are associated with batches. Once a molecule is registered, some properties (e.g., ADMET prediction, IUPAC name, chemical properties are calculated automatically. The UCD has both automated and manual data controls. Moreover, the UCD concept enables the management of user errors in the structure entry by reassigning or archiving the batches. It also allows updating of the records to include newly discovered properties of individual structures. As our research spans a wide variety of scientific fields, the database enables registration of mixtures of compounds, enantiomers, tautomers, and compounds with unknown stereochemistries.

Reacting to different types of concept drift: the Accuracy Updated Ensemble algorithm.

Science.gov (United States)

Brzezinski, Dariusz; Stefanowski, Jerzy

2014-01-01

Data stream mining has been receiving increased attention due to its presence in a wide range of applications, such as sensor networks, banking, and telecommunication. One of the most important challenges in learning from data streams is reacting to concept drift, i.e., unforeseen changes of the stream's underlying data distribution. Several classification algorithms that cope with concept drift have been put forward, however, most of them specialize in one type of change. In this paper, we propose a new data stream classifier, called the Accuracy Updated Ensemble (AUE2), which aims at reacting equally well to different types of drift. AUE2 combines accuracy-based weighting mechanisms known from block-based ensembles with the incremental nature of Hoeffding Trees. The proposed algorithm is experimentally compared with 11 state-of-the-art stream methods, including single classifiers, block-based and online ensembles, and hybrid approaches in different drift scenarios. Out of all the compared algorithms, AUE2 provided best average classification accuracy while proving to be less memory consuming than other ensemble approaches. Experimental results show that AUE2 can be considered suitable for scenarios, involving many types of drift as well as static environments.

Chemical equilibrium in the GaP-HCl and InP-HCl systems

International Nuclear Information System (INIS)

Goliusov, V.A.; Voronin, V.A.; Chuchmarev, S.K.

1983-01-01

Chemical equilibrium in the GaP-HCl and InP-HCl systems is investigated experimentally, polynomial dependence of the total pressure on temperature (800-1100 K) and hydrochloric aci concntration under the experimental conditions is obtained. The technique for equilibrium calculation in hydrogencontaining chemical systems based on the tensimetric investigation results is suggested. The equilibrium gas phase composition in the GaP(InP)-HCl systems and self consistent, within the framework of the designed equilibrium model thermodynamic characteristics are determined. The effectiveness of gas-phase indium- and gallium phosphides precipitation in the GaP(InP)-HCl systems is calculated

[Formation mechanism and chemical safety of nonintentional chemical substances present in chlorinated drinking water and wastewater].

Science.gov (United States)

Onodera, Sukeo

2010-09-01

This paper reviews the formation mechanism and chemical safety of nonintentional chemical substances (NICS) present in chlorine-treated water containing organic contaminants. Undesirable compounds, i.e., NICS, may be formed under certain conditions when chlorine reacts with organic matter. The rate and extent of chlorine consumption with organics are strongly dependent on their chemical structures, particularly whether double bonds or sulfur and nitrogen atoms occur in the molecules. Organothiophosphorus pesticides (P=S type) are easily oxidized to their phosphorus compounds (P=O type) in chlorinated water containing HOCl as little as 0.5 mg/l, resulting in an increase in cholinesterase-inhibitory activity. Chlorination of phenols in water also produces a series of highly chlorinated compounds, including chlorophenols, chloroquinones, chlorinated carboxylic acids, and polychlorinated phenoxyphenols (PCPPs). In some of these chloroquinones, 2,6-dichloroalkylsemiquinones exhibit a strong mutagenic response as do positive controls used in the Ames test. 2-phenoxyphenols in these PCPPs are particularly interesting, as they are present in the chlorine-treated phenol solution and they are also precursors (predioxins) of the highly toxic chlorinated dioxins. Polynuclear aromatic hydrocarbons (PAHs) were found to undergo chemical changes due to hypochlorite reactions to give chloro-substituted PAHs, oxygenated (quinones) and hydroxylated (phenols) compounds, but they exhibit a lower mutagenic response. In addition, field work was performed in river water and drinking water to obtain information on chemical distribution and their safety, and the results are compared with those obtained in the model chlorination experiments.

Phase transitions in thin films of Sn-Sb-Se system

International Nuclear Information System (INIS)

Samsudi Sakrani; Abdalla Belal Adam; Yussof Wahab

1998-01-01

The preparation and formation of covalent ternary Sn-Sb-Se system were investigated. A solid state reaction technique was employed whereby the evaporated multilayers of Sn/Se/Sb/Sn reacted chemically at a fixed temperature of 240 o C and were allowed to a room temperature slow-cooling. X-ray diffraction analysis showed that phase changes occurred in the system, with indication of amorphization for the predicted Sn 9 .3Sb 8 .1Se 4 4.9 and Sn 1 3.2Sb 4 3.4Se 4 3.4 compositions. These enabled the preliminary topological phase transitions of Sn-Sb-Se system according to the Gibb's triangle in which the areas of crystalline-amorphous were located. (Author)

A hybrid solar chemical looping combustion system with a high solar share

International Nuclear Information System (INIS)

Jafarian, Mehdi; Arjomandi, Maziar; Nathan, Graham J.

2014-01-01

Highlights: • A novel hybrid solar chemical looping combustion system is presented. • This hybrid CLC system integrates a CLC plant with a solar thermal energy plant. • The oxygen carrier particles are used for chemical and sensible thermal energy storage. • A solar cavity reactor is proposed for fuel reactor. • The calculations show a total solar share of around 60% can be achieved. - Abstract: A novel hybrid solar chemical looping combustion (Hy-Sol-CLC) is presented, in which the oxygen carrier particles in a CLC system are employed to provide thermal energy storage for concentrated solar thermal energy. This hybrid aims to take advantage of key features of a chemical looping combustion (CLC) system that are desirable for solar energy systems, notably their inherent chemical and sensible energy storage systems, the relatively low temperature of the “fuel” reactor (to which the concentrated solar thermal energy is added in a hybrid) relative to that of the final temperature of the product gas and the potential to operate the fuel reactor at a different pressure to the heated gas stream. By this approach, it is aimed to achieve high efficiency of the solar energy, infrastructure sharing, economic synergy, base load power generation and a high solar fraction of the total energy. In the proposed Hy-Sol-CLC system, a cavity solar receiver has been chosen for fuel reactor while for the storage of the oxygen carrier particles two reservoirs have been added to a conventional CLC. A heat exchanger is also proposed to provide independent control of the temperatures of the storage reservoirs from those of solar fuel and air reactors. The system is simulated using Aspen Plus software for the average diurnal profile of normal irradiance for Port Augusta, South Australia. The operating temperature of the fuel reactor, solar absorption efficiency, solar share, fraction of the solar thermal energy stored within the solar reactor, the fractions of sensible and

Matriptase autoactivation is tightly regulated by the cellular chemical environments.

Directory of Open Access Journals (Sweden)

Jehng-Kang Wang

Full Text Available The ability of cells to rapidly detect and react to alterations in their chemical environment, such as pH, ionic strength and redox potential, is essential for cell function and survival. We present here evidence that cells can respond to such environmental alterations by rapid induction of matriptase autoactivation. Specifically, we show that matriptase autoactivation can occur spontaneously at physiological pH, and is significantly enhanced by acidic pH, both in a cell-free system and in living cells. The acid-accelerated autoactivation can be attenuated by chloride, a property that may be part of a safety mechanism to prevent unregulated matriptase autoactivation. Additionally, the thio-redox balance of the environment also modulates matriptase autoactivation. Using the cell-free system, we show that matriptase autoactivation is suppressed by cytosolic reductive factors, with this cytosolic suppression being reverted by the addition of oxidizing agents. In living cells, we observed rapid induction of matriptase autoactivation upon exposure to toxic metal ions known to induce oxidative stress, including CoCl2 and CdCl2. The metal-induced matriptase autoactivation is suppressed by N-acetylcysteine, supporting the putative role of altered cellular redox state in metal induced matriptase autoactivation. Furthermore, matriptase knockdown rendered cells more susceptible to CdCl2-induced cell death compared to control cells. This observation implies that the metal-induced matriptase autoactivation confers cells with the ability to survive exposure to toxic metals and/or oxidative stress. Our results suggest that matriptase can act as a cellular sensor of the chemical environment of the cell that allows the cell to respond to and protect itself from changes in the chemical milieu.

A Study of Interactions between Mixing and Chemical Reaction Using the Rate-Controlled Constrained-Equilibrium Method

Science.gov (United States)

Hadi, Fatemeh; Janbozorgi, Mohammad; Sheikhi, M. Reza H.; Metghalchi, Hameed

2016-10-01

The rate-controlled constrained-equilibrium (RCCE) method is employed to study the interactions between mixing and chemical reaction. Considering that mixing can influence the RCCE state, the key objective is to assess the accuracy and numerical performance of the method in simulations involving both reaction and mixing. The RCCE formulation includes rate equations for constraint potentials, density and temperature, which allows taking account of mixing alongside chemical reaction without splitting. The RCCE is a dimension reduction method for chemical kinetics based on thermodynamics laws. It describes the time evolution of reacting systems using a series of constrained-equilibrium states determined by RCCE constraints. The full chemical composition at each state is obtained by maximizing the entropy subject to the instantaneous values of the constraints. The RCCE is applied to a spatially homogeneous constant pressure partially stirred reactor (PaSR) involving methane combustion in oxygen. Simulations are carried out over a wide range of initial temperatures and equivalence ratios. The chemical kinetics, comprised of 29 species and 133 reaction steps, is represented by 12 RCCE constraints. The RCCE predictions are compared with those obtained by direct integration of the same kinetics, termed detailed kinetics model (DKM). The RCCE shows accurate prediction of combustion in PaSR with different mixing intensities. The method also demonstrates reduced numerical stiffness and overall computational cost compared to DKM.

Invariant boxes and stability of some systems from biomathematics and chemical reactions

International Nuclear Information System (INIS)

Pavel, N.H.

1984-08-01

A general theorem on the flow-invariance of a time-dependent rectangular box with respect to a differential system is first recalled [''Analysis of some non-linear problems'' in Banach Spaces and Applications, Univ. of Iasi (Romania) (1982)]. Then a theorem applicable to the study of some differential systems from biomathematics and chemical reactions is given and proved. The theorem can be applied to enzymatic reactions, the chemical mechanism in the Belousov reaction, and the kinetic system for the chemical scheme of Hanusse of two processes with three intermediate species [in Pavel, N.H., Differential Equations, Flow-invariance and Applications, Pitman Publishing, Ltd., London (to appear)]. Next, the matrices A for which the corresponding linear system x'=Ax is component-wise positive asymptotically stable are characterized. In the Appendix a partial answer to an open problem regarding the preservation of both continuity and dissipativity in the extension of functions to a Banach space is given

Modelling of the chemical state in groundwater infiltration systems

International Nuclear Information System (INIS)

Zysset, A.

1993-01-01

Groundwater is replenished by water stemming either from precipitations, lakes or rivers. The area where such an infiltration occurs is characterized by a change in the environmental conditions, such as a decrease of the flow velocity and an increase in the solid surface marking the boundary of the flow field. With these changes new chemical processes may become relevant to the transport behavior of contaminants. Since the rates of chemical processes usually are a function of the concentrations of several species, an understanding of infiltration sites may require a multicomponent approach. The present study aims at formulating a mathematical model together with its numerical solution for groundwater infiltration sites. Such a model should improve the understanding of groundwater quality changes related to infiltrating contaminants. The groundwater quality is of vital interest to men because at many places most of the drinking water originates from groundwater. In the first part of the present study two partial models are formulated: one accounting for the transport in a one-dimensional, homogeneous and saturated porous medium, the other accounting for chemical reactions. This second model is initially stated for general kinetic systems. Then, it is specified for two systems, namely for a system governed only by reactions which are fast compared to the transport processes and for a system with biologically mediated redox reactions of dissolved substrates. In the second part of the study a numerical solution to the model is developed. For this purpose, the two partial models are coupled. The coupling is either iterative as in the case of a system with fast reactions or sequential as in all other cases. The numerical solutions of simple test cases are compared to analytical solutions. In the third part the model is evaluated using observations of infiltration sites reported in the literature. (author) figs., tabs., 155 refs

Recent advances in microbial production of fuels and chemicals using tools and strategies of systems metabolic engineering

DEFF Research Database (Denmark)

Cho, Changhee; Choi, So Young; Luo, Zi Wei

2015-01-01

The advent of various systems metabolic engineering tools and strategies has enabled more sophisticated engineering of microorganisms for the production of industrially useful fuels and chemicals. Advances in systems metabolic engineering have been made in overproducing natural chemicals...... and producing novel non-natural chemicals. In this paper, we review the tools and strategies of systems metabolic engineering employed for the development of microorganisms for the production of various industrially useful chemicals belonging to fuels, building block chemicals, and specialty chemicals......, in particular focusing on those reported in the last three years. It was aimed at providing the current landscape of systems metabolic engineering and suggesting directions to address future challenges towards successfully establishing processes for the bio-based production of fuels and chemicals from renewable...

BETWEEN THE RIGHT AND THE COMMON. HOW GROUPS REACT TO SOCIALLY UNDESIRABLE BEHAVIOUR

Directory of Open Access Journals (Sweden)

Komendant-Brodowska Agata

2017-06-01

Full Text Available The aim of the paper is to analyse the relationship between group characteristics and the scope of reaction of the group to socially undesirable behaviour. Sometimes small groups or communities fail to react to undesirable or violent behaviour and their apathy can have devastating consequences. Such a situation can occur among co-workers witnessing workplace mobbing, or neighbours who do not react to a suspicion of domestic violence. Reasons for their inaction are diverse and can include fear, doubts concerning the necessity of such a reaction, and also conformity. In the paper I examine a seemingly favourable situation: I assume that reaction is costless and all the members of the group would like to react (internalised norm, but they also want to conform. In order to analyse the factors that can influence the scope of group reaction, a structurally embedded sequential coordination game was played for different initial conditions. Computer simulations were conducted for networks of a specific type (Erd¨os-R´enyi random graph. The main aim of the analysis was to identify non-structural and structural features of the group that can impede or even block the intervention of the group. There is a positive relationship between the scope of group reaction and the strength of the internalized norm, whereas the level of conformity affects the chances of group intervention in a negative way. Heterogeneity of the group is an important factor - the scope of reaction is higher when members of the group have different levels of norm internalisation and conformity. There is a non-linear relationship between network density and the scope of reaction. Both low and high density can make it harder for people to act.

Numerical prediction of flow and mixing characteristics in CVCS chemical addition system

International Nuclear Information System (INIS)

Chang, K.S.

1999-01-01

A numerical result of the flow and mixing characteristics is presented for the flow field created by water injected into a cylindrical tank with an initially stationary fluid. The flow is relevant to the operation of the chemical addition system in the chemical and volume control system (CVCS) of nuclear power plants. This study was undertaken to provide a basis for modification of the previous design which gave a number of difficulties in installation and operation of the chemical addition system because it needs a special reciprocating pump with a high actual head. For the tank of length-to-diameter ratios (L/D) of 1, 2 and 3, each with and without a baffle inside, calculation results were obtained by solving the unsteady laminar two-dimensional elliptic forms of governing equations for the mass, momentum and species concentration. Finite-difference method was used to obtain discretization equations, and the SIMPLER solution algorithm was employed for the calculation procedure. Results showed that the baffle was very effective in enhancing the mixing in the tank, and that a baffle should be installed near the tank entrance in order to inject chemicals into the reactor coolant system (RCS) within the operating time required. (orig.)

Chemical and Metallurgy Research (CMR) Sample Tracking System Design Document

International Nuclear Information System (INIS)

Bargelski, C. J.; Berrett, D. E.

1998-01-01

The purpose of this document is to describe the system architecture of the Chemical and Metallurgy Research (CMR) Sample Tracking System at Los Alamos National Laboratory. During the course of the document observations are made concerning the objectives, constraints and limitations, technical approaches, and the technical deliverables

DESIGN, FABRICATION AND TEST OF THE REACT AND WIND, NB(3)SN, LDX FLOATING COIL CONDUCTOR

International Nuclear Information System (INIS)

SMITH, B.A.; MICHAEL, P.C.; MINERVINI, J.V.; TAKAYASU, M.; SCHULTZ, J.H.; GREGORY, E.; PYON, T.; SAMPSON, W.B.; GHOSH, A.; SCANLAN, R.

2000-01-01

The Levitated Dipole Experiment (LDX) is a novel approach for studying magnetic confinement of a fusion plasma. In this approach, a superconducting ring coil is magnetically levitated for up to 8 hours a day in the center of a 5 meter diameter vacuum vessel. The levitated coil, with on-board helium supply, is called the gloating Coil (F-Coil). Although the maximum field at the coil is only 5.3 tesla, a react-and-wind Nb 3 Sn conductor was selected because the relatively high critical temperature will enable the coil to remain levitated while it warms from 5 K to 10 K. Since pre-reacted Nb 3 Sn tape is no longer commercially available, a composite conductor was designed that contains an 18 strand Nb 3 Sn Rutherford cable. The cable was reacted and then soldered into a structural copper channel that completes the conductor and also provides quench protection. The strain state of the cable was continuously controlled during fabrication steps such as: soldering into the copper channel, spooling, and coil winding, to prevent degradation of the critical current. Measurements of strand and cable critical currents are reported, as well as estimates of the effect of fabrication, winding and operating strains on critical current

Realistic Creativity Training for Innovation Practitioners: The Know-Recognize-React Model

DEFF Research Database (Denmark)

Valgeirsdóttir, Dagný; Onarheim, Balder

2017-01-01

As creativity becomes increasingly recognized as important raw material for innovation, the importance of identifying ways to increase practitioners’ creativity through rigorously designed creativity training programs is highlighted. Therefore we sat out to design a creativity training program...... the transdisciplinary study described in this paper. Co-creation was employed as a method to ensure the three layers of focus would be taken into consideration. The result is a program called Creative Awareness Training which is based on the new Know-Recognize-React model....

Recent advances in microbial production of fuels and chemicals using tools and strategies of systems metabolic engineering.

Science.gov (United States)

Cho, Changhee; Choi, So Young; Luo, Zi Wei; Lee, Sang Yup

2015-11-15

The advent of various systems metabolic engineering tools and strategies has enabled more sophisticated engineering of microorganisms for the production of industrially useful fuels and chemicals. Advances in systems metabolic engineering have been made in overproducing natural chemicals and producing novel non-natural chemicals. In this paper, we review the tools and strategies of systems metabolic engineering employed for the development of microorganisms for the production of various industrially useful chemicals belonging to fuels, building block chemicals, and specialty chemicals, in particular focusing on those reported in the last three years. It was aimed at providing the current landscape of systems metabolic engineering and suggesting directions to address future challenges towards successfully establishing processes for the bio-based production of fuels and chemicals from renewable resources. Copyright © 2014 Elsevier Inc. All rights reserved.

Radiation-chemical formation of acids in polyvinyl butyral films with chlorinated additives

International Nuclear Information System (INIS)

Kriminiskaya, Z.K.

1993-01-01

Radiochromic indicators are commonly produced by reacting an indicator dye with an acid formed inside a polymer by irradiation. Halogenated and unhalogenated polymers were used, the latter containing halogenated organics. It was therefore of interest to study the formation of acid in polyvinyl butyral (PVD) with addition of a halogenated compound. Yields were measured of radiation-chemical acid formation in PVB films containing chloral hydrate and hexachloroethane. 5 refs., 1 fig., 2 tabs

WAR DSS: A DECISION SUPPORT SYSTEM FOR ENVIRONMENTALLY CONSCIOUS CHEMICAL PROCESS DESIGN

Science.gov (United States)

The second generation of the Waste Reduction (WAR) Algorithm is constructed as a decision support system (DSS) in the design of chemical manufacturing facilities. The WAR DSS is a software tool that can help reduce the potential environmental impacts (PEIs) of industrial chemical...

Development of chemical cleaning formulation for service water system of FBTR

International Nuclear Information System (INIS)

Velmurugan, S.; Narasimhan, S.V.; Das, P.C.; Mathur, P.K.

1995-01-01

Service water system of Fast Breeder Test Reactor (FBTR) was found to be corroded and at few locations, the corrosion product oxides were choking the smaller diameter pipelines. An attempt was made to develop a chemical cleaning formulation to chemically remove the oxides using a surface conditioner and chelating agents. Of the several complexants tested, hydroxyethylethylene diamine tetraacetic acid (HEDTA) was found to be better than other complexants from the point of view of oxide dissolution efficiency, solubility etc. A two stage chemical cleaning process involving conditioning of the oxide layer with 0.1% tannic acid followed by exposure of the conditioned oxide layer with a formulation containing 1% HEDTA + 0.5% Sodium Gluconate +0.2% hexamine was recommended to remove the corrosion product oxide present in the service water system. (author). 4 refs., 2 tabs

Hybrid Combustion-Gasification Chemical Looping

Energy Technology Data Exchange (ETDEWEB)

Herbert Andrus; Gregory Burns; John Chiu; Gregory Lijedahl; Peter Stromberg; Paul Thibeault

2009-01-07

For the past several years Alstom Power Inc. (Alstom), a leading world-wide power system manufacturer and supplier, has been in the initial stages of developing an entirely new, ultra-clean, low cost, high efficiency power plant for the global power market. This new power plant concept is based on a hybrid combustion-gasification process utilizing high temperature chemical and thermal looping technology The process consists of the oxidation, reduction, carbonation, and calcination of calcium-based compounds, which chemically react with coal, biomass, or opportunity fuels in two chemical loops and one thermal loop. The chemical and thermal looping technology can be alternatively configured as (i) a combustion-based steam power plant with CO{sub 2} capture, (ii) a hybrid combustion-gasification process producing a syngas for gas turbines or fuel cells, or (iii) an integrated hybrid combustion-gasification process producing hydrogen for gas turbines, fuel cells or other hydrogen based applications while also producing a separate stream of CO{sub 2} for use or sequestration. In its most advanced configuration, this new concept offers the promise to become the technology link from today's Rankine cycle steam power plants to tomorrow's advanced energy plants. The objective of this work is to develop and verify the high temperature chemical and thermal looping process concept at a small-scale pilot facility in order to enable AL to design, construct and demonstrate a pre-commercial, prototype version of this advanced system. In support of this objective, Alstom and DOE started a multi-year program, under this contract. Before the contract started, in a preliminary phase (Phase 0) Alstom funded and built the required small-scale pilot facility (Process Development Unit, PDU) at its Power Plant Laboratories in Windsor, Connecticut. Construction was completed in calendar year 2003. The objective for Phase I was to develop the indirect combustion loop with CO{sub 2

Chemically assisted laser ablation ICP mass spectrometry.

Science.gov (United States)

Hirata, Takafumi

2003-01-15

A new laser ablation technique combined with a chemical evaporation reaction has been developed for elemental ratio analysis of solid samples using an inductively coupled plasma mass spectrometer (ICPMS). Using a chemically assisted laser ablation (CIA) technique developed in this study, analytical repeatability of the elemental ratio measurement was successively improved. To evaluate the reliability of the CLA-ICPMS technique, Pb/U isotopic ratios were determined for zircon samples that have previously been analyzed by other techniques. Conventional laser ablation for Pb/U shows a serious elemental fractionation during ablation mainly due to the large difference in elemental volatility between Pb and U. In the case of Pb/U ratio measurement, a Freon R-134a gas (1,1,1,2-tetrafluoroethane) was introduced into the laser cell as a fluorination reactant. The Freon gas introduced into the laser cell reacts with the ablated sample U, and refractory U compounds are converted to a volatile U fluoride compound (UF6) under the high-temperature condition at the ablation site. This avoids the redeposition of U around the ablation pits. Although not all the U is reacted with Freon, formation of volatile UF compounds improves the transmission efficiency of U. Typical precision of the 206Pb/238U ratio measurement is 3-5% (2sigma) for NIST SRM 610 and Nancy 91500 zircon standard, and the U-Pb age data obtained here show good agreement within analytical uncertainties with the previously reported values. Since the observed Pb/U ratio for solid samples is relatively insensitive to laser power and ablation time, optimization of ablation conditions or acquisition parameters no longer needs to be performed on a sample-to-sample basis.

Tutorial Review: Simulation of Oscillating Chemical Reactions Using Microsoft Excel Macros

Directory of Open Access Journals (Sweden)

Abdolhossein Naseri

2016-12-01

Full Text Available Oscillating reactions are one of the most interesting topics in chemistry and analytical chemistry. Fluctuations in concentrations of one the reacting species (usually a reaction intermediate create an oscillating chemical reaction. In oscillating systems, the reaction is far from thermodynamic equilibrium. In these systems, at least one autocatalytic step is required. Developing an instinctive feeling for how oscillating reactions work will be invaluable to future generations of chemists. Some software programs have been released for simulating oscillating systems; however, the algorithm details of such software are not transparent to chemists. In contrast, function of spreadsheet tools, like Microsoft Excel, is well understood, and the software is nearly universally available. In this work, the simulation and visualization of different oscillating systems are performed using Microsoft excel. The simple repetitive solving of the ordinary differential equation of an autocatalytic reaction (a spreadsheet row followed by time, easily automated by a subroutine (a “Macro” in Excel, readily simulates an oscillating reaction. This permits the simulation of some oscillating systems such asBelousov-Zhabotinsky. The versatility of an easily understandable computational platform further enables the simulation of the effects of linear and nonlinear parameters such as concentrations of reactants and catalyst, and kinetic constants. These parameters are readily changed to examine their effects.

Modeling study of rarefied gas effects on hypersonic reacting stagnation flows

Science.gov (United States)

Wang, Zhihui; Bao, Lin

2014-12-01

Recent development of the near space hypersonic sharp leading vehicles has raised a necessity to fast and accurately predict the aeroheating in hypersonic rarefied flows, which challenges our understanding of the aerothermodynamics and aerothermochemistry. The present flow and heat transfer problem involves complex rarefied gas effects and nonequilibrium real gas effects which are beyond the scope of the traditional prediction theory based on the continuum hypothesis and equilibrium assumption. As a typical example, it has been found that the classical Fay-Riddell equation fails to predict the stagnation point heat flux, when the flow is either rarefied or chemical nonequilibrium. In order to design a more general theory covering the rarefied reacting flow cases, an intuitive model is proposed in this paper to describe the nonequilibrium dissociation-recombination flow along the stagnation streamline towards a slightly blunted nose in hypersonic rarefied flows. Some characteristic flow parameters are introduced, and based on these parameters, an explicitly analytical bridging function is established to correct the traditional theory to accurately predict the actual aeroheating performance. It is shown that for a small size nose in medium density flows, the flow at the outer edge of the stagnation point boundary layer could be highly nonequilibrium, and the aeroheating performance is distinguished from that of the big blunt body reentry flows at high altitudes. As a result, when the rarefied gas effects and the nonequilibrium real gas effects are both significant, the classical similarity law could be questionable, and it is inadequate to directly analogize results from the classical blunt body reentry problems to the present new generation sharp-leading vehicles. In addition, the direct simulation Monte Carlo method is also employed to validate the conclusion.

Effects of radiative heat transfer on the turbulence structure in inert and reacting mixing layers

International Nuclear Information System (INIS)

Ghosh, Somnath; Friedrich, Rainer

2015-01-01

We use large-eddy simulation to study the interaction between turbulence and radiative heat transfer in low-speed inert and reacting plane temporal mixing layers. An explicit filtering scheme based on approximate deconvolution is applied to treat the closure problem arising from quadratic nonlinearities of the filtered transport equations. In the reacting case, the working fluid is a mixture of ideal gases where the low-speed stream consists of hydrogen and nitrogen and the high-speed stream consists of oxygen and nitrogen. Both streams are premixed in a way that the free-stream densities are the same and the stoichiometric mixture fraction is 0.3. The filtered heat release term is modelled using equilibrium chemistry. In the inert case, the low-speed stream consists of nitrogen at a temperature of 1000 K and the highspeed stream is pure water vapour of 2000 K, when radiation is turned off. Simulations assuming the gas mixtures as gray gases with artificially increased Planck mean absorption coefficients are performed in which the large-eddy simulation code and the radiation code PRISSMA are fully coupled. In both cases, radiative heat transfer is found to clearly affect fluctuations of thermodynamic variables, Reynolds stresses, and Reynolds stress budget terms like pressure-strain correlations. Source terms in the transport equation for the variance of temperature are used to explain the decrease of this variance in the reacting case and its increase in the inert case

Large scale sodium interactions. Part 3. Chemical phenomena with limestone concrete

International Nuclear Information System (INIS)

Sallach, R.A.

1977-01-01

The description of the chemical processes and reaction products resulting from the exposure of concrete to molten sodium metal is important for a thorough, realistic assessment of the safety of CRBR-type reactors. Concretes are in general complex heterogenous substances whose ingredients can be derived from many sources. Consequently a wide variety of reaction processes and products might be anticipated. Initial attention has focused on a concrete in which both the aggregate and sandy components are derived from limestone. Presented are the chemical observations and experimental data from tests in which molten sodium metal at approximately 500 0 C is dropped into cold limestone concrete crucibles. Thermocouples immersed in the sodium pool indicate that the reaction proceeds in two stages. In the first stage which lasts 5 to 8 minutes, the temperature of the reacting mass hovers around 500 0 C. This stage is followed by a second stage of longer duration--greater than 100 minutes--where the temperature is 700 to 800 0 C. The main reaction product is a hard, fused, black slag which contains about 3/4 of the sodium in the initial charge. A secondary product is sodium oxide aerosol which accounts for the remaining 1/4 of the charge. It is significant that no free sodium metal is found in the slag; all sodium has completely reacted

Essentials of water systems design in the oil, gas, and chemical processing industries

CERN Document Server

Bahadori, Alireza; Boyd, Bill

2013-01-01

Essentials of Water Systems Design in the Oil, Gas and Chemical Processing Industries provides valuable insight for decision makers by outlining key technical considerations and requirements of four critical systems in industrial processing plants—water treatment systems, raw water and plant water systems, cooling water distribution and return systems, and fire water distribution and storage facilities. The authors identify the key technical issues and minimum requirements related to the process design and selection of various water supply systems used in the oil, gas, and chemical processing industries. This book is an ideal, multidisciplinary work for mechanical engineers, environmental scientists, and oil and gas process engineers.

PENGARUH MODEL PEMBELAJARAN INKUIRI BERSTRATEGI REACT TERHADAP HASIL BELAJAR KIMIA SISWA SMA KELAS XI

Directory of Open Access Journals (Sweden)

Riva Ismawati

2015-11-01

Full Text Available This study aimed to determine the effect of inquiry learning model with REACT strategy on learning outcomes and to determine the contribution to the learning outcomes. The expected benefits are improvements in learning chemistry subjects in class XI of high school through constructivism learning activities. The population in this study were students of class XI of high school in Semarang. The analysis showed the early stages of the population have the same degree of homogeneity and normal distribution. Average learning outcomes after experimental class treated were better than the control class, which amounted to 75.52 and 67.14. Test the difference between two average results obtained t from calculation (4.85> t from table (1.66, so we can conclude the experimental class learning results are better than the control class. Correlation test resulted biserial correlation coefficient (rb of 0.58 and t from calculation (5.68> t from table (1.99, so the influence was significant. Effect of application of inquiry learning model with REACT strategy shown by the coefficient of determination of 33.64%.The cognitive learning outcomes of experimental class had reached mastery learning classical while control class not yet. The average value of affective and psychomotor experimental classes are better than the control class. Based on these results, it can be concluded that the inquiry learning with REACT strategy have positive effect on learning outcomes chemistry in student class XI of high school in Semarang.

Multiphase integral reacting flow computer code (ICOMFLO): User`s guide

Energy Technology Data Exchange (ETDEWEB)

Chang, S.L.; Lottes, S.A.; Petrick, M.

1997-11-01

A copyrighted computational fluid dynamics computer code, ICOMFLO, has been developed for the simulation of multiphase reacting flows. The code solves conservation equations for gaseous species and droplets (or solid particles) of various sizes. General conservation laws, expressed by elliptic type partial differential equations, are used in conjunction with rate equations governing the mass, momentum, enthalpy, species, turbulent kinetic energy, and turbulent dissipation. Associated phenomenological submodels of the code include integral combustion, two parameter turbulence, particle evaporation, and interfacial submodels. A newly developed integral combustion submodel replacing an Arrhenius type differential reaction submodel has been implemented to improve numerical convergence and enhance numerical stability. A two parameter turbulence submodel is modified for both gas and solid phases. An evaporation submodel treats not only droplet evaporation but size dispersion. Interfacial submodels use correlations to model interfacial momentum and energy transfer. The ICOMFLO code solves the governing equations in three steps. First, a staggered grid system is constructed in the flow domain. The staggered grid system defines gas velocity components on the surfaces of a control volume, while the other flow properties are defined at the volume center. A blocked cell technique is used to handle complex geometry. Then, the partial differential equations are integrated over each control volume and transformed into discrete difference equations. Finally, the difference equations are solved iteratively by using a modified SIMPLER algorithm. The results of the solution include gas flow properties (pressure, temperature, density, species concentration, velocity, and turbulence parameters) and particle flow properties (number density, temperature, velocity, and void fraction). The code has been used in many engineering applications, such as coal-fired combustors, air

Basic chemically recuperated gas turbines--power plant optimization and thermodynamics second law analysis

International Nuclear Information System (INIS)

Alves, Lourenco Gobira; Nebra, Silvia Azucena

2004-01-01

One of the proposals to increase the performance of the gas turbines is to improve chemical recuperated cycle. In this cycle, the heat in the turbine exhaust gases is used to heat and modify the chemical characteristics of the fuel. One mixture of natural gas and steam receives heat from the exhaust turbine gases; the mixture components react among themselves producing hot synthesis gas. In this work, an analysis and nonlinear optimization of the cycle were made in order to investigate the temperature and pressure influence on the global cycle performance. The chemical composition in the reformer was assumed according to chemical equilibrium equations, which presents good agreement with data from literature. The mixture of hot gases was treated like ideal gases. The maximum net profit was achieved and a thermodynamic second law analysis was made in order to detect the greatest sources of irreversibility

Numerical solutions of several reflected shock-wave flow fields with nonequilibrium chemical reactions

Science.gov (United States)

Hanson, R. K.; Presley, L. L.; Williams, E. V.

1972-01-01

The method of characteristics for a chemically reacting gas is used in the construction of the time-dependent, one-dimensional flow field resulting from the normal reflection of an incident shock wave at the end wall of a shock tube. Nonequilibrium chemical reactions are allowed behind both the incident and reflected shock waves. All the solutions are evaluated for oxygen, but the results are generally representative of any inviscid, nonconducting, and nonradiating diatomic gas. The solutions clearly show that: (1) both the incident- and reflected-shock chemical relaxation times are important in governing the time to attain steady state thermodynamic properties; and (2) adjacent to the end wall, an excess-entropy layer develops wherein the steady state values of all the thermodynamic variables except pressure differ significantly from their corresponding Rankine-Hugoniot equilibrium values.

Audit Report. Johnston Atoll Chemical Agent Disposal System Preparation for Year 2000

National Research Council Canada - National Science Library

1998-01-01

.... The overall audit objective was to determine whether the Johnston Atoll Chemical Agent Disposal System was adequately preparing its information technology systems to resolve date-processing issues...

Nonequilibrium thermodynamics transport and rate processes in physical, chemical and biological systems

CERN Document Server

Demirel, Yasar

2014-01-01

Natural phenomena consist of simultaneously occurring transport processes and chemical reactions. These processes may interact with each other and may lead to self-organized structures, fluctuations, instabilities, and evolutionary systems. Nonequilibrium Thermodynamics, 3rd edition emphasizes the unifying role of thermodynamics in analyzing the natural phenomena. This third edition updates and expands on the first and second editions by focusing on the general balance equations for coupled processes of physical, chemical, and biological systems. The new edition contains a new chapte

Study of the chemical composition of the resinous exudate isolated from Heliotropium sclerocarpum and evaluation of the antioxidant properties of the phenolic compounds and the resin.

Science.gov (United States)

Modak, Brenda; Salina, Melissa; Rodilla, Jesús; Torres, René

2009-11-12

Heliotropium sclerocarpum Phil. (Heliotropiaceae) is a resinous bush that grows in the Atacama of northern Chile. The chemical composition of its resinous exudate was analyzed for the first time. One aromatic geranyl derivative: filifolinol (1), one flavanone: naringenin (2) and a new type of 3-oxo-2-arylbenzofuran derivative 3 were isolated and their structures were determined. The antioxidant activity of the phenolic compounds and resin was evaluated using the bleaching of DPPH radical method and expressed as fast reacting equivalents (FRE) and total reacting equivalents (TRE).

On energetics of hydrocarbon chemical reactions by ionizing irradiation

International Nuclear Information System (INIS)

Zaykin, Yu.A.; Zaykina, R.F.; Mirkin, G.

2002-01-01

Complete text of publication follows. The present global energy crisis requires the industry to look for technologies that are more effective and, particularly, less energy consuming. The hydrocarbon processing technology based on the electron radiation-induced thermal chemical conversion has a great potential. Comparing the presently predominant thermocatalytic processing, it is much more energy efficient, because chemical conversions go at a minimal processing temperature and pressure. To compare energy consumption by electron irradiation with thermal and thermocatalytic technologies of hydrocarbon processing one must see major differences between them. While traditional thermocatalytic processes are equilibrium and their energetics can be evaluated based on principles of classic thermodynamics, HEET processing is non-equilibrium and this evaluation approach is not valid for it. However, a theoretical description of radiation-chemical conversion using reaction rate constants determined in thermally equilibrium systems is approximately adequate to radiation processes by substituting equilibrium concentrations of reacting particles as their non-equilibrium concentrations under irradiation. In particular, description of radical reactions initiated by radiation requires substitution of thermally equilibrium radical concentration by much higher concentration defined by the dynamic equilibrium of radical radiation generation and their recombination. The paper presents the comparative analysis of energy consumption in different stages of hydrocarbon processing using classic thermal cracking by heating versus radiation induced cracking. It is shown that in the most energy-consuming stage of processing - the chain reaction initiation necessary for concentration of active radicals, irradiation processing has the great advantage compared to thermal cracking by heating and allows cutting down the total energy consumption by approximately 40%

Design of High Quality Chemical XOR Gates with Noise Reduction.

Science.gov (United States)

Wood, Mackenna L; Domanskyi, Sergii; Privman, Vladimir

2017-07-05

We describe a chemical XOR gate design that realizes gate-response function with filtering properties. Such gate-response function is flat (has small gradients) at and in the vicinity of all the four binary-input logic points, resulting in analog noise suppression. The gate functioning involves cross-reaction of the inputs represented by pairs of chemicals to produce a practically zero output when both are present and nearly equal. This cross-reaction processing step is also designed to result in filtering at low output intensities by canceling out the inputs if one of the latter has low intensity compared with the other. The remaining inputs, which were not reacted away, are processed to produce the output XOR signal by chemical steps that result in filtering at large output signal intensities. We analyze the tradeoff resulting from filtering, which involves loss of signal intensity. We also discuss practical aspects of realizations of such XOR gates. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

MINEQL, Chemical Equilibrium Composition of Aqueous Systems

International Nuclear Information System (INIS)

Westall, John C.; Zachary, Joseph L.; Morel, Francois M.M.; Parsons, Ralph M.; Schweingruber, M.

1994-01-01

1 - Description of program or function: MINEQL is a subroutine package to calculate equilibrium composition of an aqueous system, accounting for mass transfer. MINEQL-EIR contains an additional base on enthalpy and heat capacity data and has the option to do calculations at temperatures different from 25 degrees C. 2 - Method of solution: In MINEQL, the Gibbs free-energy function is minimized and mass balance chemical reaction equations are solved simultaneously. In MINEQL-EIR, the iteration scheme to solve the system of equations has been improved to make the probability of divergence very small. 3 - Restrictions on the complexity of the problem: MINEQL does not take into account mass transfer of water molecules

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.

40 CFR 63.443 - Standards for the pulping system at kraft, soda, and semi-chemical processes.

Science.gov (United States)

2010-07-01

... Paper Industry § 63.443 Standards for the pulping system at kraft, soda, and semi-chemical processes. (a... operator of each pulping system using a semi-chemical or soda process subject to the requirements of this... kraft, soda, and semi-chemical processes. 63.443 Section 63.443 Protection of Environment ENVIRONMENTAL...

Photochemistry of limonene secondary organic aerosol studied with chemical ionization mass spectrometry

Science.gov (United States)

Pan, Xiang

Limonene is one of the most abundant monoterpenes in the atmosphere. Limonene easily reacts with gas-phase oxidants in air such as NO3, ozone and OH. Secondary organic aerosol (SOA) is formed when low vapor pressure products condense into particles. Chemicals in SOA particles can undergo further reactions with oxidants and with solar radiation that significantly change SOA composition over the course of several days. The goal of this work was to characterize radiation induced reaction in SOA. To perform experiments, we have designed and constructed an Atmospheric Pressure Chemical Ionization Mass Spectrometer (APCIMS) coupled to a photochemical cell containing SOA samples. In APCIMS, (H2O)nH 3O+ clusters are generated in a 63Ni source and react with gaseous organic analytes. Most organic chemicals are not fragmented by the ionization process. We have focused our attention on limonene SOA prepared in two different ways. The first type of SOA is produced by oxidation of limonene by ozone; and the second type of SOA is formed by the NO3-induced oxidation of limonene. They model the SOA formed under daytime and nighttime conditions, respectively. Ozone initiated oxidation is the most important chemical sink for limonene both indoors, where it is used for cleaning purposes, and outdoors. Terpenes are primarily oxidized by reactions with NO3 at night time. We generated limonene SOA under different ozone and limonene concentrations. The resulting SOA samples were exposed to wavelength-tunable radiation in the UV-Visible range between 270 nm and 630 nm. The results show that the photodegradation rates strongly depend on radiation wavelengths. Gas phase photodegradation products such as acetone, formaldehyde, acetaldehyde, and acetic acid were shown to have different production rates for SOA formed in different concentration conditions. Even for SOA prepared under the lowest concentrations, the SOA photodegradation was efficient. The conclusion is that exposure of SOA to

From Detailed Description of Chemical Reacting Carbon Particles to Subgrid Models for CFD

Directory of Open Access Journals (Sweden)

Schulze S.

2013-04-01

Full Text Available This work is devoted to the development and validation of a sub-model for the partial oxidation of a spherical char particle moving in an air/steam atmosphere. The particle diameter is 2 mm. The coal particle is represented by moisture- and ash-free nonporous carbon while the coal rank is implemented using semi-global reaction rate expressions taken from the literature. The submodel includes six gaseous chemical species (O2, CO2, CO, H2O, H2, N2. Three heterogeneous reactions are employed, along with two homogeneous semi-global reactions, namely carbon monoxide oxidation and the water-gas-shift reaction. The distinguishing feature of the subgrid model is that it takes into account the influence of homogeneous reactions on integral characteristics such as carbon combustion rates and particle temperature. The sub-model was validated by comparing its results with a comprehensive CFD-based model resolving the issues of bulk flow and boundary layer around the particle. In this model, the Navier-Stokes equations coupled with the energy and species conservation equations were used to solve the problem by means of the pseudo-steady state approach. At the surface of the particle, the balance of mass, energy and species concentration was applied including the effect of the Stefan flow and heat loss due to radiation at the surface of the particle. Good agreement was achieved between the sub-model and the CFD-based model. Additionally, the CFD-based model was verified against experimental data published in the literature (Makino et al. (2003 Combust. Flame 132, 743-753. Good agreement was achieved between numerically predicted and experimentally obtained data for input conditions corresponding to the kinetically controlled regime. The maximal discrepancy (10% between the experiments and the numerical results was observed in the diffusion-controlled regime. Finally, we discuss the influence of the Reynolds number, the ambient O2 mass fraction and the ambient

Improving integrative searching of systems chemical biology data using semantic annotation.

Science.gov (United States)

Chen, Bin; Ding, Ying; Wild, David J

2012-03-08

Systems chemical biology and chemogenomics are considered critical, integrative disciplines in modern biomedical research, but require data mining of large, integrated, heterogeneous datasets from chemistry and biology. We previously developed an RDF-based resource called Chem2Bio2RDF that enabled querying of such data using the SPARQL query language. Whilst this work has proved useful in its own right as one of the first major resources in these disciplines, its utility could be greatly improved by the application of an ontology for annotation of the nodes and edges in the RDF graph, enabling a much richer range of semantic queries to be issued. We developed a generalized chemogenomics and systems chemical biology OWL ontology called Chem2Bio2OWL that describes the semantics of chemical compounds, drugs, protein targets, pathways, genes, diseases and side-effects, and the relationships between them. The ontology also includes data provenance. We used it to annotate our Chem2Bio2RDF dataset, making it a rich semantic resource. Through a series of scientific case studies we demonstrate how this (i) simplifies the process of building SPARQL queries, (ii) enables useful new kinds of queries on the data and (iii) makes possible intelligent reasoning and semantic graph mining in chemogenomics and systems chemical biology. Chem2Bio2OWL is available at http://chem2bio2rdf.org/owl. The document is available at http://chem2bio2owl.wikispaces.com.

Performance metrics for the evaluation of hyperspectral chemical identification systems

Science.gov (United States)

Truslow, Eric; Golowich, Steven; Manolakis, Dimitris; Ingle, Vinay

2016-02-01

Remote sensing of chemical vapor plumes is a difficult but important task for many military and civilian applications. Hyperspectral sensors operating in the long-wave infrared regime have well-demonstrated detection capabilities. However, the identification of a plume's chemical constituents, based on a chemical library, is a multiple hypothesis testing problem which standard detection metrics do not fully describe. We propose using an additional performance metric for identification based on the so-called Dice index. Our approach partitions and weights a confusion matrix to develop both the standard detection metrics and identification metric. Using the proposed metrics, we demonstrate that the intuitive system design of a detector bank followed by an identifier is indeed justified when incorporating performance information beyond the standard detection metrics.

Errors of Students Learning With React Strategy in Solving the Problems of Mathematical Representation Ability

Directory of Open Access Journals (Sweden)

Delsika Pramata Sari

2017-06-01

Full Text Available The purpose of this study was to investigate the errors experienced by students learning with REACT strategy and traditional learning in solving problems of mathematical representation ability. This study used quasi experimental pattern with static-group comparison design. The subjects of this study were 47 eighth grade students of junior high school in Bandung consisting of two samples. The instrument used was a test to measure students' mathematical representation ability. The reliability coefficient about the mathematical representation ability was 0.56. The most prominent errors of mathematical representation ability of students learning with REACT strategy and traditional learning, was on indicator that solving problem involving arithmetic symbols (symbolic representation. In addition, errors were also experienced by many students with traditional learning on the indicator of making the image of a real world situation to clarify the problem and facilitate its completion (visual representation.

Study on chemical buffering property of GMZ sodium bentonite under atmospheric condition

International Nuclear Information System (INIS)

Wen Zhijian

2012-01-01

At present, the deep geological disposal is regarded as the most reasonable and effective way to safely disposal the high-level radioactive wastes in the world. The conceptual model of HLW geological disposal in China is based on a multi-barrier system that combines an isolating geological environment with an engineered barrier system. The buffer is one of the engineered barrier materials and GMZ Na-bentonite is selected as the basic material. One of the most important functions related to buffer is the chemical buffering, which means buffering the changes in pore water chemistry. This paper presents the experiments of GMZ-1 Na-bentonite reacted with distilled water under atmospheric condition. The batch tests and results discussion are reported. Na and Mg in batch test solution are co-provided by interlayer cations of montmorillonite and solids dissolution, K and Ca are provided by dissolution of solids. The result is a pre-requisite for predicting near-field nuclide migration and assesses the long-term stability of the engineered barrier materials. (author)

Development of clean chemical mechanical polishing systems; Clean CMP system

Energy Technology Data Exchange (ETDEWEB)

Tsujimura, M.; Hosokawa, M. [Ebara Corp., Tokyo (Japan)

1998-10-20

Described herein are clean chemical mechanical polishing (CMP) systems developed by Ebara. A CMP system needs advanced peripheral techniques, in addition to those for grinding adopted by the conventional system, in order to fully exhibit its inherent functions. An integrated design concept is essential for the CMP steps, including slurry supplying, polishing, washing, process controlling and waste fluid treatment. The Ebara has adopted a standard concept `Clean CMP, dry-in and dry-out of wafers,` and provided world`s highest grades of techniques for inter-layer insulating film, shallow trench isolation, plug and wiring. The head for the polishing module is specially designed by FEM, to improve homogeneity of wafers from the center to edges. The dresser is also specially designed, to improve pad surface topolody after dressing. A slurry dipsersing method is developed to reduce slurry consumption. Various washing modules, designed to have the same external shape, can be allocated to various functions. 10 figs.

Investigation of the properties of fully reacted unstoichiometric polydimethylsiloxane networks and their extracted network fractions

DEFF Research Database (Denmark)

Frankær, Sarah Maria Grundahl; Jensen, Mette Krog; Bejenariu, Anca Gabriela

2012-01-01

We investigated the linear dynamic response of a series of fully reacted unstoichiometric polydimethylsiloxane (PDMS) networks and of the two corresponding network fractions namely the sol and the washed network. The sol and the washed network were separated by a simple extraction process. This way...

Economic analysis of coal-based polygeneration system for methanol and power production

International Nuclear Information System (INIS)

Lin, Hu; Jin, Hongguang; Gao, Lin; Han, Wei

Polygeneration system for chemical and power co-production has been regarded as one of promising technologies to use fossil fuel more efficiently and cleanly. In this paper the thermodynamic and economic performances of three types of coal-based polygeneration system were investigated and the influence of energy saving of oxygenation systems on system economic performance was revealed. The primary cost saving ratio (PCS) is presented as a criterion, which represents the cost saving of polygeneration system compared with the single-product systems with the same products outputs, to evaluate economic advantages of polygeneration system. As a result, the system, adopting un-reacted syngas partly recycled to the methanol synthesis reactor and without the shift process, can get the optimal PCS of 11.8%, which results from the trade-off between the installed capital cost saving and the energy saving effects on the cost saving, and represents the optimal coupling relationship among chemical conversion, energy utilization and economic performance. And both of fuel price and the level of equipment capital cost affect on PCS faintly. This paper provides an evaluation method for polygeneration systems based on both technical and economic viewpoints. (author)

Study of the Chemical Composition of the Resinous Exudate Isolated from Heliotropium Sclerocarpum and Evaluation of the Antioxidant Properties of the Phenolic Compounds and the Resin

Directory of Open Access Journals (Sweden)

René Torres

2009-11-01

Full Text Available Heliotropium sclerocarpum Phil. (Heliotropiaceae is a resinous bush that grows in the Atacama of northern Chile. The chemical composition of its resinous exudate was analyzed for the first time. One aromatic geranyl derivative: filifolinol (1, one flavanone: naringenin (2 and a new type of 3-oxo-2-arylbenzofuran derivative 3 were isolated and their structures were determined. The antioxidant activity of the phenolic compounds and resin was evaluated using the bleaching of DPPH radical method and expressed as fast reacting equivalents (FRE and total reacting equivalents (TRE.

33 CFR 149.416 - What are the requirements for a dry chemical fire suppression system?

Science.gov (United States)

2010-07-01

... the requirements for a dry chemical fire suppression system? Each natural gas deepwater port must be... dry chemical fire suppression system? 149.416 Section 149.416 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) DEEPWATER PORTS DEEPWATER PORTS: DESIGN, CONSTRUCTION...

Pulse-density modulation control of chemical oscillation far from equilibrium in a droplet open-reactor system.

Science.gov (United States)

Sugiura, Haruka; Ito, Manami; Okuaki, Tomoya; Mori, Yoshihito; Kitahata, Hiroyuki; Takinoue, Masahiro

2016-01-20

The design, construction and control of artificial self-organized systems modelled on dynamical behaviours of living systems are important issues in biologically inspired engineering. Such systems are usually based on complex reaction dynamics far from equilibrium; therefore, the control of non-equilibrium conditions is required. Here we report a droplet open-reactor system, based on droplet fusion and fission, that achieves dynamical control over chemical fluxes into/out of the reactor for chemical reactions far from equilibrium. We mathematically reveal that the control mechanism is formulated as pulse-density modulation control of the fusion-fission timing. We produce the droplet open-reactor system using microfluidic technologies and then perform external control and autonomous feedback control over autocatalytic chemical oscillation reactions far from equilibrium. We believe that this system will be valuable for the dynamical control over self-organized phenomena far from equilibrium in chemical and biomedical studies.

INSPACE CHEMICAL PROPULSION SYSTEMS AT NASA's MARSHALL SPACE FLIGHT CENTER: HERITAGE AND CAPABILITIES

Science.gov (United States)

McRight, P. S.; Sheehy, J. A.; Blevins, J. A.

2005-01-01

NASA s Marshall Space Flight Center (MSFC) is well known for its contributions to large ascent propulsion systems such as the Saturn V rocket and the Space Shuttle external tank, solid rocket boosters, and main engines. This paper highlights a lesser known but very rich side of MSFC-its heritage in the development of in-space chemical propulsion systems and its current capabilities for spacecraft propulsion system development and chemical propulsion research. The historical narrative describes the flight development activities associated with upper stage main propulsion systems such as the Saturn S-IVB as well as orbital maneuvering and reaction control systems such as the S-IVB auxiliary propulsion system, the Skylab thruster attitude control system, and many more recent activities such as Chandra, the Demonstration of Automated Rendezvous Technology (DART), X-37, the X-38 de-orbit propulsion system, the Interim Control Module, the US Propulsion Module, and multiple technology development activities. This paper also highlights MSFC s advanced chemical propulsion research capabilities, including an overview of the center s Propulsion Systems Department and ongoing activities. The authors highlight near-term and long-term technology challenges to which MSFC research and system development competencies are relevant. This paper concludes by assessing the value of the full range of aforementioned activities, strengths, and capabilities in light of NASA s exploration missions.

Application of a reversible chemical reaction system to solar thermal power plants

Science.gov (United States)

Hanseth, E. J.; Won, Y. S.; Seibowitz, L. P.

1980-01-01

Three distributed dish solar thermal power systems using various applications of SO2/SO3 chemical energy storage and transport technology were comparatively assessed. Each system features various roles for the chemical system: (1) energy storage only, (2) energy transport, or (3) energy transport and storage. These three systems were also compared with the dish-Stirling, using electrical transport and battery storage, and the central receiver Rankine system, with thermal storage, to determine the relative merit of plants employing a thermochemical system. As an assessment criterion, the busbar energy costs were compared. Separate but comparable solar energy cost computer codes were used for distributed receiver and central receiver systems. Calculations were performed for capacity factors ranging from 0.4 to 0.8. The results indicate that SO2/SO3 technology has the potential to be more cost effective in transporting the collected energy than in storing the energy for the storage capacity range studied (2-15 hours)

Fabrication of a Combustion-Reacted High-Performance ZnO Electron Transport Layer with Silver Nanowire Electrodes for Organic Solar Cells.

Science.gov (United States)

Park, Minkyu; Lee, Sang-Hoon; Kim, Donghyuk; Kang, Juhoon; Lee, Jung-Yong; Han, Seung Min

2018-02-28

Herein, a new methodology for solution-processed ZnO fabrication on Ag nanowire network electrode via combustion reaction is reported, where the amount of heat emitted during combustion was minimized by controlling the reaction temperature to avoid damaging the underlying Ag nanowires. The degree of participation of acetylacetones, which are volatile fuels in the combustion reaction, was found to vary with the reaction temperature, as revealed by thermogravimetric and compositional analyses. An optimized processing temperature of 180 °C was chosen to successfully fabricate a combustion-reacted ZnO and Ag nanowire hybrid electrode with a sheet resistance of 30 Ω/sq and transmittance of 87%. A combustion-reacted ZnO on Ag nanowire hybrid structure was demonstrated as an efficient transparent electrode and electron transport layer for the PTB7-Th-based polymer solar cells. The superior electrical conductivity of combustion-reacted ZnO, compared to that of conventional sol-gel ZnO, increased the external quantum efficiency over the entire absorption range, whereas a unique light scattering effect due to the presence of nanopores in the combustion-derived ZnO further enhanced the external quantum efficiency in the 450-550 nm wavelength range. A power conversion efficiency of 8.48% was demonstrated for the PTB7-Th-based polymer solar cell with the use of a combustion-reacted ZnO/Ag NW hybrid transparent electrode.

Determination of solute organic concentration in contaminated soils using a chemical-equilibrium soil column system

DEFF Research Database (Denmark)

Gamst, Jesper; Kjeldsen, Peter; Christensen, Thomas Højlund

2007-01-01

using two soils with different content of organic carbon (f(oc) of 1.5 and 6.5%, respectively). A quadruple blind test of the ER-V system using glass beads in stead of soil showed an acceptable recovery (65-85%) of all of the 11 VOCs tested. Only for the most volatile compound (heptane, K-H similar...... to 80) an unacceptable recovery was found (9%). The contact time needed for obtaining chemical equilibrium was tested in the ER-H system by performing five test with different duration (1, 2, 4, 7 and 19 days) using the low organic carbon soil. Seven days of contact time appeared sufficient...... for determination of solute concentration in a contaminated soil were developed; (1) a chemical Equilibrium and Recirculation column test for Volatile organic chemicals (ER-V) and (2) a chemical Equilibrium and Recirculation column test for Hydrophobic organic chemicals (ER-H). The two test systems were evaluated...

Where do organic chemicals found in soil systems come from

International Nuclear Information System (INIS)

Dragun, J.; Mason, S.A.; Barkach, J.H.

1991-01-01

Today's regulatory climate encourages the private sector to assess the environmental condition of their facilities. An environmental assessment often includes the collection of soil samples. Despite the trend to obtain reams of numbers to show the presence of chemicals, many misconceptions exist among environmental scientists and engineers regarding the interpretation of those numbers. The presence of organic chemicals in soil may or may not be problematic. This depends primarily upon the source. If an industrial point source is responsible for the spill or bulk release, then remedial activity usually ensues. However, if the source is not an industrial release, then remedial activity may not be required. This paper will briefly discuss the sources, other than industrial point sources, responsible for the presence of organic chemicals in soil systems

Reaction Mechanism Generator: Automatic construction of chemical kinetic mechanisms

Science.gov (United States)

Gao, Connie W.; Allen, Joshua W.; Green, William H.; West, Richard H.

2016-06-01

Reaction Mechanism Generator (RMG) constructs kinetic models composed of elementary chemical reaction steps using a general understanding of how molecules react. Species thermochemistry is estimated through Benson group additivity and reaction rate coefficients are estimated using a database of known rate rules and reaction templates. At its core, RMG relies on two fundamental data structures: graphs and trees. Graphs are used to represent chemical structures, and trees are used to represent thermodynamic and kinetic data. Models are generated using a rate-based algorithm which excludes species from the model based on reaction fluxes. RMG can generate reaction mechanisms for species involving carbon, hydrogen, oxygen, sulfur, and nitrogen. It also has capabilities for estimating transport and solvation properties, and it automatically computes pressure-dependent rate coefficients and identifies chemically-activated reaction paths. RMG is an object-oriented program written in Python, which provides a stable, robust programming architecture for developing an extensible and modular code base with a large suite of unit tests. Computationally intensive functions are cythonized for speed improvements.

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.

Modulated molecular beam mass spectrometry: A generalized expression for the ''reaction product vector'' for linear systems

International Nuclear Information System (INIS)

Chang, H.; Weinberg, W.H.

1977-01-01

A generalized expression is developed that relates the ''reaction product vector'', epsilon exp(-iphi), to the kinetic parameters of a linear system. The formalism is appropriate for the analysis of modulated molecular beam mass spectrometry data and facilitates the correlation of experimental results to (proposed) linear models. A study of stability criteria appropriate for modulated molecular beam mass spectrometry experiments is also presented. This investigation has led to interesting inherent limitations which have not heretofore been emphasized, as well as a delineation of the conditions under which stable chemical oscillations may occur in the reacting system

Evaluation of a porcine internal mammary artery (No-React II) as a small-diameter conduit

NARCIS (Netherlands)

Ostapczuk, S; Poniewierski, J; Thiel, A; Knieriem, HJ; Orlowski, T; Rakhorst, G; Krian, A

1998-01-01

Background. The patency of biologic small-diameter vascular grafts in the aortocoronary position is still unsatisfactory. Most of the studies suggest that xeno-grafts are to be avoided as an aortocoronary bypass. Methods. The porcine internal mammary artery treated by the No-React II procedure was

Tillage, fertilization systems and chemical attributes of a Paleudult

Directory of Open Access Journals (Sweden)

Evelyn Penedo Dorneles

2015-02-01

Full Text Available Tillage and fertilization methods may affect soil fertility. With the aim of assessing changes in soil chemical properties over a period of ten years, soil samples of a Paleudult were collected over nine seasons at three layer depths (0-5, 5-10, 10-20 cm and were chemically analyzed. Grain yield and nutrient export in two summer crops, soybean (Glycine max and corn (Zea mays, in a field experiment set in Eldorado do Sul, in the state of Rio Grande do Sul, Brazil, were determined. Three soil tillage systems were evaluated, conventional (CT, reduced (RT and no-tillage (NT, combined with mineral (lime and fertilizers and organic (poultry litter fertilization. The no-tillage system stood out as compared to the others, especially in the surface layer, in terms of values of organic matter, soil pH, available phosphorus, cation exchange capacity and base saturation. Phosphorus content was higher under organic than mineral fertilization due to the criteria used for the establishment of fertilizer doses. Under organic fertilization, soil pH values were similar to those obtained in limed soil samples because of the cumulative effect of the organic fertilizer. Soybean yield was lower under NT in comparison to the RT and CT systems. Consequently, soybean grain exported a lower content of nutrients than maize grain. Maize yield was not affected by either tillage or fertilization systems.

Improving integrative searching of systems chemical biology data using semantic annotation

Directory of Open Access Journals (Sweden)

Chen Bin

2012-03-01

Full Text Available Abstract Background Systems chemical biology and chemogenomics are considered critical, integrative disciplines in modern biomedical research, but require data mining of large, integrated, heterogeneous datasets from chemistry and biology. We previously developed an RDF-based resource called Chem2Bio2RDF that enabled querying of such data using the SPARQL query language. Whilst this work has proved useful in its own right as one of the first major resources in these disciplines, its utility could be greatly improved by the application of an ontology for annotation of the nodes and edges in the RDF graph, enabling a much richer range of semantic queries to be issued. Results We developed a generalized chemogenomics and systems chemical biology OWL ontology called Chem2Bio2OWL that describes the semantics of chemical compounds, drugs, protein targets, pathways, genes, diseases and side-effects, and the relationships between them. The ontology also includes data provenance. We used it to annotate our Chem2Bio2RDF dataset, making it a rich semantic resource. Through a series of scientific case studies we demonstrate how this (i simplifies the process of building SPARQL queries, (ii enables useful new kinds of queries on the data and (iii makes possible intelligent reasoning and semantic graph mining in chemogenomics and systems chemical biology. Availability Chem2Bio2OWL is available at http://chem2bio2rdf.org/owl. The document is available at http://chem2bio2owl.wikispaces.com.

Cross-reacting antibacterial auto-antibodies are produced within coronary atherosclerotic plaques of acute coronary syndrome patients.

Directory of Open Access Journals (Sweden)

Filippo Canducci

Full Text Available Coronary atherosclerosis, the main condition predisposing to acute myocardial infarction, has an inflammatory component caused by stimuli that are yet unknown. We molecularly investigated the nature of the immune response within human coronary lesion in four coronary plaques obtained by endoluminal atherectomy from four patients. We constructed phage-display libraries containing the IgG1/kappa antibody fragments produced by B-lymphocytes present in each plaque. By immunoaffinity, we selected from these libraries a monoclonal antibody, arbitrarily named Fab7816, able to react both with coronary and carotid atherosclerotic tissue samples. We also demonstrated by confocal microscopy that this monoclonal antibody recognized human transgelin type 1, a cytoskeleton protein involved in atherogenesis, and that it co-localized with fibrocyte-like cells transgelin+, CD68+, CD45+ in human sections of coronary and carotid plaques. In vitro fibrocytes obtained by differentiating CD14+ cells isolated from peripheral blood mononuclear cells also interacted with Fab7816, thus supporting the hypothesis of a specific recognition of fibrocytes into the atherosclerotic lesions. Interestingly, the same antibody, cross-reacted with the outer membrane proteins of Proteus mirabilis and Klebsiella pneumoniae (and possibly with homologous proteins of other enterobacteriaceae present in the microbiota. From all the other three libraries, we were able to clone, by immunoaffinity selection, human monoclonal antibodies cross-reacting with bacterial outer membrane proteins and with transgelin. These findings demonstrated that in human atherosclerotic plaques a local cross-reactive immune response takes place.

[Advances in novel carrier systems of chemical constituents from spice volatile oils].

Science.gov (United States)

Zhang, Jia-jia; Zhu, Yuan; Yu, Jiang-nan; Xu, Xi-ming

2015-10-01

Recent years, chemical constituents from spice volatile oils have gained worldwide concern owing to its multiple pharmacological effects and safety for using as the natural antibacterial agents. However, their poor dissolution, strong volatility, serious irritation, weak stability, easy oxidation and low bioavailability characteristics are the major obstacle in the preparation of effective oral formulation and practical application. Therefore, there is an urgent need to select a novel carrier system that can delivery the chemical constituents from spice volatile oils more efficiently with improving their stability as well as alleviating the irritation, and develop the functional food, health products and even medicine for exerting their pharmacological effects, which also is the focus and nodus of the research on their application. This review presents recent systematic studies on their novel carrier systems, including cyclodextrin inclusion complex, liposomes, nanoemulsions, nanoparticles, solid dispersion and so on, and summarizes the characteristics, application range and problems of each novel carrier systems, in order to provide some beneficial thoughts in further developing new products of chemical constituents from spice volatile oils.

Competitor's marketing : How banks acquire and react to knowledge about their competitor's marketing.

OpenAIRE

Puelma, Rodrigo; Persson, Annika

2008-01-01

Abstract   Introduction The way banks compete has changed dramatically during recent years, mostly because of international trends such as advances in information technology, globalisation and deregulations. This has made competition harsher meaning that survival and success requires knowledge about the competitors and understanding about the way they act and react. Within marketing there is a need to identify suitable strategies to acquire knowledge about competitor’s marketing and methods t...

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

Maintenance Management Systems in the Czech Enterprises of Chemical and Food Industries

Directory of Open Access Journals (Sweden)

Lenka Branska

2016-12-01

Full Text Available Purpose of the article: The aim of this article is to use the results of the qualitative research to describe the current form of maintenance systems used in enterprises of chemical and food industries, and then to discuss and generalize the results. Methodology/methods: The primary qualitative research was conducted in five companies, which can be regarded as typical representatives of the industries. The main objective of the primary research in individual companies was to determine how they perform the strategic and tactical operational planning of maintenance, implementation of these plans and their control. Individual interviews with respondents were used as the research method. The results of the research were processed using the content analysis method. Subsequently, comparison of the findings from individual businesses and subsequent synthesis thereof was performed, which allowed making generalizations. Scientific aim: The scientific aim of the article is to develop knowledge in the field of maintenance management by specifying the form of the maintenance systems utilized in Czech enterprises of the chemical and food industries and identifying the main opportunities for their improvement. Findings: Czech enterprises of the chemical and food industries utilize maintenance management systems. These systems are aimed at prevention, emphasizing the planning of maintenance activities in fixed periodic intervals. Also, they often utilize diagnostic maintenance. However, the maintenance systems currently used cannot be considered fully operational, with regard to the relatively large volume of after-failure repairs. Conclusions: Production equipment maintenance systems are irreplaceable in chemical and food industry enterprises, but there is great potential for improvement. Improvement should be focused on the area of strategic as well as tactical and operational planning of production equipment maintenance. In terms of strategy, the biggest

Effect of borohydride addition rate on chemically prepared amorphous Fe-B particles

International Nuclear Information System (INIS)

Koch, C.B.; Morup, S.; Linderoth, S.

1991-01-01

Amorphous Fe-B alloys can be prepared by reacting aqueous solutions of Fe salts and NaBH 4 . In this paper the effect of the addition rate of the NaBH 4 solution to the FeSO 4 solution on the precipitate is investigated. The chemical composition of the amorphous alloys formed varies between Fe 79 B 21 and Fe 68 B 32 . The hyperfine parameters of the alloys, derived from Mossbauer spectra, show a decrease from 29 to 25 T of the magnetic hyperfine field and an increase from 0.19 to 0.28 mms -1 of the isomer shift with increasing NaBH 4 addition rate. The results suggest that alloys with different structures but identical composition may be produced by chemical reduction

Electrochemical/chemical oxidation of bisphenol A in a four-electron/two-proton process in aprotic organic solvents

International Nuclear Information System (INIS)

Chan, Ya Yun; Yue, Yanni; Li, Yongxin; Webster, Richard D.

2013-01-01

Graphical abstract: - Highlights: • Bisphenol A undergoes a chemically irreversible voltammetric oxidation process. • Chemical oxidation was performed to overcome adsorption effects that cause electrode fouling. • A new product was isolated from chemical oxidation with 4 mol equiv. of the one-electron oxidant, NO + . • The oxidative mechanism was proposed to be a four-electron/two-proton process. - Abstract: The electrochemical behavior of bisphenol A (BPA) was examined using cyclic voltammetry, bulk electrolysis and chemical oxidation in aprotic organic solvents. It was found that BPA undergoes a chemically irreversible voltammetric oxidation process to form compounds that cannot be electrochemically converted back to the starting materials on the voltammetric timescale. To overcome the effects of electrode fouling during controlled potential electrolysis experiments, NO + was used as a one-electron chemical oxidant. A new product, hydroxylated bisdienone was isolated from the chemical oxidation of BPA with 4 mol equiv of NO + SbF 6 − in low water content CH 3 CN. The structure of the cation intermediate species was deduced and it was proposed that BPA is oxidized in a four-electron/two-proton process to form a relatively unstable dication which reacts quickly in the presence of water in acetonitrile (in a mechanism that is similar to phenols in general). However, as the water content of the solvent increased it was found that the chemical oxidation mechanism produced a nitration product in high yield. The findings from this study provide useful insights into the reactions that can occur during oxidative metabolism of BPA and highlight the possibility of the role of a bisdienone cation as a reactive metabolite in biological systems

'Reacting to the unknown': experiencing the first birth at home or in hospital in Australia.

Science.gov (United States)

Dahlen, Hannah G; Barclay, Lesley; Homer, Caroline S E

2010-08-01

to explore the experiences of a small group of first-time mothers giving birth at home or in hospital. a grounded theory methodology was used. Data were generated from in-depth interviews with women in their own homes. Sydney, Australia. 19 women were interviewed. Seven women who gave birth for the first time in a public hospital and seven women who gave birth for the first time at home were interviewed, and their experiences were contrasted with two mothers who gave birth for the first time in a birth centre, one mother who gave birth for the first time in a private hospital and two women who had given birth more than once. these women shared common experiences of giving birth as 'novices'. Regardless of birth setting, they were all 'reacting to the unknown'. As they entered labour, the women chose different levels of responsibility for their birth. They also readjusted their expectations when the reality of labour occurred, reacted to the 'force' of labour, and connected or disconnected from the labour and eventually the baby. knowing that first-time mothers, irrespective of birth setting, are essentially 'reacting to the unknown' as they negotiate the experience of birth, could alter the way in which care is provided and increase the sensitivity of midwives to women's needs. Most importantly, midwives need to be aware of the need to help women adjust their expectations during labour and birth. Identifying the 'novice' status of first-time mothers also better explains previous research that reports unrealistic expectations and fear that may be associated with first-time birthing. Crown Copyright 2008. Published by Elsevier Ltd. All rights reserved.

"Reacting to the Past" to Be Proactive in the Present: Feminist Roots of High-Impact Practices

Science.gov (United States)

Lidinsky, April

2014-01-01

In this article, the author explains a high-impact role-playing pedagogy developed at Barnard College called "Reacting to the Past," which she uses to introduce first-year and general education students to feminist history, current feminist issues, and feminist pedagogy.

CHEMSIMUL - A program package for numerical simulation of chemical reaction systems

International Nuclear Information System (INIS)

Lang Rasmussen, O.; Bjergbakke, E.

1984-01-01

A description is given of a program package, CHEMSIMUL, for numerical simulation of chemical reaction systems. The main components in the package are a translator of chemical equations to differential equations, a balance equation program, a differential equation solver, EPISODE, and an input/output program. The performance of the program is demonstrated by four examples. A manual for the input file and the complete program text with comments are given in Appendices I and II. (author)

Chemical Evolution of Groundwater Near a Sinkhole Lake, Northern Florida: 2. Chemical Patterns, Mass Transfer Modeling, and Rates of Mass Transfer Reactions

Science.gov (United States)

Katz, Brian G.; Plummer, L. Niel; Busenberg, Eurybiades; Revesz, Kinga M.; Jones, Blair F.; Lee, Terrie M.

1995-06-01

Chemical patterns along evolutionary groundwater flow paths in silicate and carbonate aquifers were interpreted using solute tracers, carbon and sulfur isotopes, and mass balance reaction modeling for a complex hydrologic system involving groundwater inflow to and outflow from a sinkhole lake in northern Florida. Rates of dominant reactions along defined flow paths were estimated from modeled mass transfer and ages obtained from CFC-modeled recharge dates. Groundwater upgradient from Lake Barco remains oxic as it moves downward, reacting with silicate minerals in a system open to carbon dioxide (CO2), producing only small increases in dissolved species. Beneath and downgradient of Lake Barco the oxic groundwater mixes with lake water leakage in a highly reducing, silicate-carbonate mineral environment. A mixing model, developed for anoxic groundwater downgradient from the lake, accounted for the observed chemical and isotopic composition by combining different proportions of lake water leakage and infiltrating meteoric water. The evolution of major ion chemistry and the 13C isotopic composition of dissolved carbon species in groundwater downgradient from the lake can be explained by the aerobic oxidation of organic matter in the lake, anaerobic microbial oxidation of organic carbon, and incongruent dissolution of smectite minerals to kaolinite. The dominant process for the generation of methane was by the CO2 reduction pathway based on the isotopic composition of hydrogen (δ2H(CH4) = -186 to -234‰) and carbon (δ13C(CH4) = -65.7 to -72.3‰). Rates of microbial metabolism of organic matter, estimated from the mass transfer reaction models, ranged from 0.0047 to 0.039 mmol L-1 yr-1 for groundwater downgradient from the lake.

Recent Activities in Electro-Thermal Chemical Launcher Technologies at BAE Systems

National Research Council Canada - National Science Library

Dyvik, Jahn; Herbig, Juleigh; Appleton, Randall; O'Reilly, John; Shin, Jonathan

2006-01-01

..., improvement of power connections to the gun to allow electromagnetic field containment and automated connection to the round, and tests of the completed ETC system with various chemical propellants...

Desarrollo de una aplicación móvil mediante React-Native

OpenAIRE

Raja Lentijo, David

2018-01-01

In this document has been developed an application to share food recipes with social format where the users can interact between them. The goal of this applications is to create a global platform when users wants to find something related with cooking, know where have to go and don't have to use a web browser. All has developed with React-Native that allows to develop native applications for Android and IOS platforms, and reduce the processing time respect to hybrid applications. Also, the co...

Predicting Anatomical Therapeutic Chemical (ATC) Classification of Drugs by Integrating Chemical-Chemical Interactions and Similarities

Science.gov (United States)

Chen, Lei; Zeng, Wei-Ming; Cai, Yu-Dong; Feng, Kai-Yan; Chou, Kuo-Chen

2012-01-01

The Anatomical Therapeutic Chemical (ATC) classification system, recommended by the World Health Organization, categories drugs into different classes according to their therapeutic and chemical characteristics. For a set of query compounds, how can we identify which ATC-class (or classes) they belong to? It is an important and challenging problem because the information thus obtained would be quite useful for drug development and utilization. By hybridizing the informations of chemical-chemical interactions and chemical-chemical similarities, a novel method was developed for such purpose. It was observed by the jackknife test on a benchmark dataset of 3,883 drug compounds that the overall success rate achieved by the prediction method was about 73% in identifying the drugs among the following 14 main ATC-classes: (1) alimentary tract and metabolism; (2) blood and blood forming organs; (3) cardiovascular system; (4) dermatologicals; (5) genitourinary system and sex hormones; (6) systemic hormonal preparations, excluding sex hormones and insulins; (7) anti-infectives for systemic use; (8) antineoplastic and immunomodulating agents; (9) musculoskeletal system; (10) nervous system; (11) antiparasitic products, insecticides and repellents; (12) respiratory system; (13) sensory organs; (14) various. Such a success rate is substantially higher than 7% by the random guess. It has not escaped our notice that the current method can be straightforwardly extended to identify the drugs for their 2nd-level, 3rd-level, 4th-level, and 5th-level ATC-classifications once the statistically significant benchmark data are available for these lower levels. PMID:22514724

Investigations on the optimum design of chemical addition system for nuclear power plants

Energy Technology Data Exchange (ETDEWEB)

Chang, Byong Hoon [Junior College of Inchon, Inchon (Korea, Republic of); Chung, Chang Kyu; Choi, Han Rim; Kim, Eun Kee; Ro, Tae Sun [Korea Power Engineering Company, Inc. Taejon (Korea, Republic of)

1998-12-31

Mixing characteristics of the chemical additives in the chemical injection tank of the chemical and volume control system(CVCS) were investigated for the Yonggwang Nuclear units 5 and 6. Numerical calculations were performed with a low-Reynolds number turbulence model. Studies were also conducted for the injection tank with a disk located at 1/4H, 2/4H, and 3/4H from the inlet in order to see the effect in the enhancement of chemical mixing. Results show that the optimum arrangement is to locate a disk close to the inlet. 10 refs., 4 figs. (Author)

Investigations on the optimum design of chemical addition system for nuclear power plants

Energy Technology Data Exchange (ETDEWEB)

Chang, Byong Hoon [Junior College of Inchon, Inchon (Korea, Republic of); Chung, Chang Kyu; Choi, Han Rim; Kim, Eun Kee; Ro, Tae Sun [Korea Power Engineering Company, Inc. Taejon (Korea, Republic of)

1997-12-31

Mixing characteristics of the chemical additives in the chemical injection tank of the chemical and volume control system(CVCS) were investigated for the Yonggwang Nuclear units 5 and 6. Numerical calculations were performed with a low-Reynolds number turbulence model. Studies were also conducted for the injection tank with a disk located at 1/4H, 2/4H, and 3/4H from the inlet in order to see the effect in the enhancement of chemical mixing. Results show that the optimum arrangement is to locate a disk close to the inlet. 10 refs., 4 figs. (Author)

System and method for treatment of a medium

Science.gov (United States)

Singh, Surinder Prabhjot; Acharya, Harish Radhakrishna; Perry, Robert James; McDermott, John Brian

2017-05-23

A system and method for treatment of a medium is disclosed. The system includes a plurality of separator zones and a plurality of heat transfer zones. Each of the separator zone and the heat transfer zone among the plurality of separator zones and heat transfer zones respectively, are disposed alternatively in a flow duct. Further, each separator zone includes an injector device for injecting a sorbent into the corresponding separator zone. Within the corresponding separator zone, the injected sorbent is reacted with a gaseous medium flowing in the flow duct, so as to generate a reacted gaseous medium and a reacted sorbent. Further, each heat transfer zone exchanges heat between the reacted gaseous medium fed from the corresponding separator zone and a heat transfer medium.

Errors of Students Learning with React Strategy in Solving the Problems of Mathematical Representation Ability

Science.gov (United States)

Sari, Delsika Pramata; Darhim; Rosjanuardi, Rizky

2018-01-01

The purpose of this study was to investigate the errors experienced by students learning with REACT strategy and traditional learning in solving problems of mathematical representation ability. This study used quasi experimental pattern with static-group comparison design. The subjects of this study were 47 eighth grade students of junior high…

Gaussian approximations for stochastic systems with delay: Chemical Langevin equation and application to a Brusselator system

International Nuclear Information System (INIS)

Brett, Tobias; Galla, Tobias

2014-01-01

We present a heuristic derivation of Gaussian approximations for stochastic chemical reaction systems with distributed delay. In particular, we derive the corresponding chemical Langevin equation. Due to the non-Markovian character of the underlying dynamics, these equations are integro-differential equations, and the noise in the Gaussian approximation is coloured. Following on from the chemical Langevin equation, a further reduction leads to the linear-noise approximation. We apply the formalism to a delay variant of the celebrated Brusselator model, and show how it can be used to characterise noise-driven quasi-cycles, as well as noise-triggered spiking. We find surprisingly intricate dependence of the typical frequency of quasi-cycles on the delay period

Gaussian approximations for stochastic systems with delay: chemical Langevin equation and application to a Brusselator system.

Science.gov (United States)

Brett, Tobias; Galla, Tobias

2014-03-28

We present a heuristic derivation of Gaussian approximations for stochastic chemical reaction systems with distributed delay. In particular, we derive the corresponding chemical Langevin equation. Due to the non-Markovian character of the underlying dynamics, these equations are integro-differential equations, and the noise in the Gaussian approximation is coloured. Following on from the chemical Langevin equation, a further reduction leads to the linear-noise approximation. We apply the formalism to a delay variant of the celebrated Brusselator model, and show how it can be used to characterise noise-driven quasi-cycles, as well as noise-triggered spiking. We find surprisingly intricate dependence of the typical frequency of quasi-cycles on the delay period.

Recent Theoretical Approaches to Minimal Artificial Cells

Directory of Open Access Journals (Sweden)

Fabio Mavelli

2014-05-01

Full Text Available Minimal artificial cells (MACs are self-assembled chemical systems able to mimic the behavior of living cells at a minimal level, i.e. to exhibit self-maintenance, self-reproduction and the capability of evolution. The bottom-up approach to the construction of MACs is mainly based on the encapsulation of chemical reacting systems inside lipid vesicles, i.e. chemical systems enclosed (compartmentalized by a double-layered lipid membrane. Several researchers are currently interested in synthesizing such simple cellular models for biotechnological purposes or for investigating origin of life scenarios. Within this context, the properties of lipid vesicles (e.g., their stability, permeability, growth dynamics, potential to host reactions or undergo division processes… play a central role, in combination with the dynamics of the encapsulated chemical or biochemical networks. Thus, from a theoretical standpoint, it is very important to develop kinetic equations in order to explore first—and specify later—the conditions that allow the robust implementation of these complex chemically reacting systems, as well as their controlled reproduction. Due to being compartmentalized in small volumes, the population of reacting molecules can be very low in terms of the number of molecules and therefore their behavior becomes highly affected by stochastic effects both in the time course of reactions and in occupancy distribution among the vesicle population. In this short review we report our mathematical approaches to model artificial cell systems in this complex scenario by giving a summary of three recent simulations studies on the topic of primitive cell (protocell systems.

Chemically reacting fluid flow induced by an exponentially accelerated infinite vertical plate in a magnetic field and variable temperature via LTT and FEM

Directory of Open Access Journals (Sweden)

Srinivasa Raju R.

2016-01-01

Full Text Available In this research paper, we found both numerical and analytical solutions for the effect of chemical reaction on unsteady, incompressible, viscous fluid flow past an exponentially accelerated vertical plate with heat absorption and variable temperature in a magnetic field. The flow problem is governed by a system of coupled non-linear partial differential equations with suitable boundary conditions. We have solved the governing equations by an efficient, accurate, powerful finite element method (FEM as well as Laplace transform technique (LTT. The evaluation of the numerical results are performed and graphical results for the velocity, temperature and concentration profiles within the boundary layer are discussed. Also, the expressions for the skin-friction, Nusselt number and the Sherwood number coefficients have been derived and discussed through graphs and tabular forms for different values of the governing parameters.

Chemical Kinetics of Hydrocarbon Ignition in Practical Combustion Systems

International Nuclear Information System (INIS)

Westbrook, C.K.

2000-01-01

Chemical kinetic factors of hydrocarbon oxidation are examined in a variety of ignition problems. Ignition is related to the presence of a dominant chain branching reaction mechanism that can drive a chemical system to completion in a very short period of time. Ignition in laboratory environments is studied for problems including shock tubes and rapid compression machines. Modeling of the laboratory systems are used to develop kinetic models that can be used to analyze ignition in practical systems. Two major chain branching regimes are identified, one consisting of high temperature ignition with a chain branching reaction mechanism based on the reaction between atomic hydrogen with molecular oxygen, and the second based on an intermediate temperature thermal decomposition of hydrogen peroxide. Kinetic models are then used to describe ignition in practical combustion environments, including detonations and pulse combustors for high temperature ignition, and engine knock and diesel ignition for intermediate temperature ignition. The final example of ignition in a practical environment is homogeneous charge, compression ignition (HCCI) which is shown to be a problem dominated by the kinetics intermediate temperature hydrocarbon ignition. Model results show why high hydrocarbon and CO emissions are inevitable in HCCI combustion. The conclusion of this study is that the kinetics of hydrocarbon ignition are actually quite simple, since only one or two elementary reactions are dominant. However, there are many combustion factors that can influence these two major reactions, and these are the features that vary from one practical system to another

Reliability Evaluation and Improvement Approach of Chemical Production Man - Machine - Environment System

Science.gov (United States)

Miao, Yongchun; Kang, Rongxue; Chen, Xuefeng

2017-12-01

In recent years, with the gradual extension of reliability research, the study of production system reliability has become the hot topic in various industries. Man-machine-environment system is a complex system composed of human factors, machinery equipment and environment. The reliability of individual factor must be analyzed in order to gradually transit to the research of three-factor reliability. Meanwhile, the dynamic relationship among man-machine-environment should be considered to establish an effective blurry evaluation mechanism to truly and effectively analyze the reliability of such systems. In this paper, based on the system engineering, fuzzy theory, reliability theory, human error, environmental impact and machinery equipment failure theory, the reliabilities of human factor, machinery equipment and environment of some chemical production system were studied by the method of fuzzy evaluation. At last, the reliability of man-machine-environment system was calculated to obtain the weighted result, which indicated that the reliability value of this chemical production system was 86.29. Through the given evaluation domain it can be seen that the reliability of man-machine-environment integrated system is in a good status, and the effective measures for further improvement were proposed according to the fuzzy calculation results.

Therapeutic preparations of IVIg contain naturally occurring anti-HLA-E antibodies that react with HLA-Ia (HLA-A/-B/-Cw) alleles.

Science.gov (United States)

Ravindranath, Mepur H; Terasaki, Paul I; Pham, Tho; Jucaud, Vadim; Kawakita, Satoru

2013-03-14

The US Food and Drug Administration approved intravenous immunoglobulin (IVIg), extracted from the plasma of thousands of blood donors, for removing HLA antibodies (Abs) in highly sensitized patients awaiting organ transplants. Since the blood of healthy individuals has HLA Abs, we tested different IVIg preparations for reactivity to HLA single antigen Luminex beads. All preparations showed high levels of HLA-Ia and -Ib reactivity. Since normal nonalloimmunized males have natural antibodies to the heavy chains (HCs) of HLA antigens, the preparations were then tested against iBeads coated only with intact HLA antigens. All IVIg preparations varied in level of antibody reactivity to intact HLA antigens. We raised monoclonal Abs against HLA-E that mimicked IVIg's HLA-Ia and HLA-Ib reactivity but reacted only to HLA-I HCs. Inhibition experiments with synthetic peptides showed that HLA-E shares epitopes with HLA-Ia alleles. Importantly, depleting anti-HLA-E Abs from IVIg totally eliminated the HLA-Ia reactivity of IVIg. Since anti-HLA-E mAbs react with HLA-Ia, they might be useful in suppressing HLA antibody production, similar to the way anti-RhD Abs suppress production. At the same time, anti-HLA-E mAb, which reacts only to HLA-I HCs, is unlikely to produce transfusion-related acute lung injury, in contrast to antibodies reacting to intact-HLA.

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

International Nuclear Information System (INIS)

Besmann, T.M.

1986-01-01

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

Porous TiO₂-Based Gas Sensors for Cyber Chemical Systems to Provide Security and Medical Diagnosis.

Science.gov (United States)

Galstyan, Vardan

2017-12-19

Gas sensors play an important role in our life, providing control and security of technical processes, environment, transportation and healthcare. Consequently, the development of high performance gas sensor devices is the subject of intense research. TiO₂, with its excellent physical and chemical properties, is a very attractive material for the fabrication of chemical sensors. Meanwhile, the emerging technologies are focused on the fabrication of more flexible and smart systems for precise monitoring and diagnosis in real-time. The proposed cyber chemical systems in this paper are based on the integration of cyber elements with the chemical sensor devices. These systems may have a crucial effect on the environmental and industrial safety, control of carriage of dangerous goods and medicine. This review highlights the recent developments on fabrication of porous TiO₂-based chemical gas sensors for their application in cyber chemical system showing the convenience and feasibility of such a model to provide the security and to perform the diagnostics. The most of reports have demonstrated that the fabrication of doped, mixed and composite structures based on porous TiO₂ may drastically improve its sensing performance. In addition, each component has its unique effect on the sensing properties of material.

Chemical Stimulation of Engineered Geothermal Systems

Energy Technology Data Exchange (ETDEWEB)

Rose, Peter, E.

2008-08-08

The objective of this project is to design, develop and demonstrate methods for the chemical stimulation of candidate EGS reservoirs as well as the chemical treatment of mineral-scaled wellbores. First, a set of candidate chemical compounds capable of dissolving calcite was identified. A series of tests was then performed on each candidate in order to screen it for thermal stability and reactivity towards calcite. A detailed analysis was then performed on each compound that emerged from the screening tests in order to characterize its decay kinetics and reaction kinetics as functions of temperature and chemical composition. From among the compounds emerging from the laboratory studies, one compounds was chosen for a field experiment in order to verify the laboratory predictions.

Chemical shift-based identification of monosaccharide spin-systems with NMR spectroscopy to complement untargeted glycomics.

Science.gov (United States)

Klukowski, Piotr; Schubert, Mario

2018-06-15

A better understanding of oligosaccharides and their wide-ranging functions in almost every aspect of biology and medicine promises to uncover hidden layers of biology and will support the development of better therapies. Elucidating the chemical structure of an unknown oligosaccharide is still a challenge. Efficient tools are required for non-targeted glycomics. Chemical shifts are a rich source of information about the topology and configuration of biomolecules, whose potential is however not fully explored for oligosaccharides. We hypothesize that the chemical shifts of each monosaccharide are unique for each saccharide type with a certain linkage pattern, so that correlated data measured by NMR spectroscopy can be used to identify the chemical nature of a carbohydrate. We present here an efficient search algorithm, GlycoNMRSearch, that matches either a subset or the entire set of chemical shifts of an unidentified monosaccharide spin system to all spin systems in an NMR database. The search output is much more precise than earlier search functions and highly similar matches suggest the chemical structure of the spin system within the oligosaccharide. Thus searching for connected chemical shift correlations within all electronically available NMR data of oligosaccharides is a very efficient way of identifying the chemical structure of unknown oligosaccharides. With an improved database in the future, GlycoNMRSearch will be even more efficient deducing chemical structures of oligosaccharides and there is a high chance that it becomes an indispensable technique for glycomics. The search algorithm presented here, together with a graphical user interface, is available at http://glyconmrsearch.santos.pwr.edu.pl. Supplementary data are available at Bioinformatics online.

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)

Chemical and Biological Defense: DOD Needs Consistent Policies and Clear Processes to Address the Survivability of Weapon Systems Against Chemical and Biological Threats

National Research Council Canada - National Science Library

2006-01-01

DOD, joint, and military service weapon system acquisition policies inconsistently address and do not establish a clear process for considering and testing system chemical and biological survivability...

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.

Changes in the Chemistry of Groundwater Reacted with CO2: Comparison of Laboratory Results with the ZERT Field Pilot

Science.gov (United States)

Kharaka, Yousif K.; Thordsen, James J.; Abedini, Atosa A.; Beers, Sarah; Thomas, Burt

2017-01-01

As part of the ZERT program, sediments from two wells at the ZERT site, located in Bozeman, Montana, USA were reacted with a solution having the composition of local groundwater. A total of 50 water samples were collected from 7 containers placed for 15 days in a glove box with one atmosphere of CO2 to investigate detailed changes in the concentrations of major, minor and trace inorganic compounds, and to compare these with changes observed in groundwater at the ZERT site following CO2 injection. Laboratory results included rapid changes in pH (8.6 to 5.7), alkalinity (243 to 1295 mg/L as HCO3), electrical conductance (539 to 1822 μS/cm), Ca (28 to 297 mg/L), Mg (18 to 63 mg/L), Fe (5 to 43 μg/L) and Mn (2 to 837 μg/L) following CO2 injection. These chemical changes, which are in general agreement with those obtained from sampling the ZERT monitoring wells, could provide early detection of CO2 leakage into shallow groundwater. Dissolution of calcite, some dolomite and minor Mn-oxides, and desorption/ion exchange are likely the main geochemical processes responsible for the observed changes.

[Research on determination of chemical purity of andrographolide by coulometric titration method].

Science.gov (United States)

Yang, Ning; Yang, Dezhi; Xu, Lishen; Lv, Yang

2010-04-01

The determination of chemical purity of andrographolide by coulometric titration method is studied in this paper. The coulometric titration was carried out in a mixture composed of 4 mol x L(-1) hydrochloric acid and 1 mol x L(-1) potassium bromide solution and 1 mol x L(-1) potassium nitrate solution (1:1). Bromine is electrogenerated at the anode and reacts with the andrographolide. The number of electrons involved in the eleatrode reaction is 2. Purity of andrographolide is 99.76% compared with 99.77% utilizing area normalization method by HPLC. The RSD are 0.33% and 0.02% respectively. The results from two methods are consistent, so the determination of chemical purity of andrographolide by coulometric titration method is scientific and feasible. The method is rapid, simple, convenient, sensitive and accurate. The reference material is not essential in the method. The method is suitable for determination of chemical purity of andrographolide.

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

Science.gov (United States)

West, William; Whitacre, Jay; Lim, James

2008-01-01

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

Computer program determines chemical composition of physical system at equilibrium

Science.gov (United States)

Kwong, S. S.

1966-01-01

FORTRAN 4 digital computer program calculates equilibrium composition of complex, multiphase chemical systems. This is a free energy minimization method with solution of the problem reduced to mathematical operations, without concern for the chemistry involved. Also certain thermodynamic properties are determined as byproducts of the main calculations.

Water system integration of a chemical plant

International Nuclear Information System (INIS)

Zheng Pingyou; Feng Xiao; Qian Feng; Cao Dianliang

2006-01-01

Water system integration can minimize both the freshwater consumption and the wastewater discharge of a plant. In industrial applications, it is the key to determine reasonably the contaminants and the limiting concentrations, which will decide the freshwater consumption and wastewater discharge of the system. In this paper, some rules to determine the contaminants and the limiting concentrations are proposed. As a case study, the water system in a chemical plant that produces sodium hydroxide and PVC (polyvinyl chloride) is integrated. The plant consumes a large amount of freshwater and discharges a large amount of wastewater, so minimization of both the freshwater consumption and the wastewater discharge is very important to it. According to the requirements of each water using process on the water used in it, the contaminants and the limiting concentrations are determined. Then, the optimal water reuse scheme is firstly studied based on the water network with internal water mains. To reduce the freshwater consumption and the wastewater discharge further, decentralized regeneration recycling is considered. The water using network is simplified by mixing some of the used water. After the water system integration, the freshwater consumption is reduced 25.5%, and the wastewater discharge is reduced 48%

Tracking the behavior of Maillard browning in lysine/arginine-sugar model systems under high hydrostatic pressure.

Science.gov (United States)

Ma, Xiao-Juan; Gao, Jin-Yan; Tong, Ping; Li, Xin; Chen, Hong-Bing

2017-12-01

High-pressure processing is gaining popularity in the food industry. However, its effect on the Maillard reaction during high-pressure-assisted pasteurization and sterilization is not well documented. This study aimed to investigate the effects of high hydrostatic pressure on the Maillard reaction during these processes using amino acid (lysine or arginine)-sugar (glucose or fructose) solution models. High pressure retarded the intermediate and final stages of the Maillard reaction in the lysine-sugar model. For the lysine-glucose model, the degradation rate of Amadori compounds was decelerated, while acceleration was observed in the arginine-sugar model. Increased temperature not only accelerated the Maillard reaction over time but also formed fluorescent compounds with different emission wavelengths. Lysine reacted with the sugars more readily than arginine under the same conditions. In addition, it was easier for lysine to react with glucose, whereas arginine reacted more readily with fructose under high pressure. High pressure exerts different effects on lysine-sugar and arginine-sugar models. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Adaptive Finite Element Method Assisted by Stochastic Simulation of Chemical Systems

KAUST Repository

Cotter, Simon L.; Vejchodský , Tomá š; Erban, Radek

2013-01-01

Stochastic models of chemical systems are often analyzed by solving the corresponding Fokker-Planck equation, which is a drift-diffusion partial differential equation for the probability distribution function. Efficient numerical solution of the Fokker-Planck equation requires adaptive mesh refinements. In this paper, we present a mesh refinement approach which makes use of a stochastic simulation of the underlying chemical system. By observing the stochastic trajectory for a relatively short amount of time, the areas of the state space with nonnegligible probability density are identified. By refining the finite element mesh in these areas, and coarsening elsewhere, a suitable mesh is constructed and used for the computation of the stationary probability density. Numerical examples demonstrate that the presented method is competitive with existing a posteriori methods. © 2013 Society for Industrial and Applied Mathematics.

Experimental-demonstrative system for energy conversion using hydrogen fuel cell - preliminary results

International Nuclear Information System (INIS)

Stoenescu, D.; Stefanescu, I.; Patularu, I.; Culcer, M.; Lazar, R.E.; Carcadea, E.; Mirica, D. . E-mail address of corresponding author: daniela@icsi.ro; Stoenescu, D.)

2005-01-01

It is well known that hydrogen is the most promising solution of future energy, both for long and medium term strategies. Hydrogen can be produced using many primary sources (natural gas, methane, biomass, etc.), it can be burned or chemically react having a high yield of energy conversion, being a non-polluted fuel. This paper presents the preliminary results obtained by ICSI Rm. Valcea in an experimental-demonstrative conversion energy system made by a sequence of hydrogen purification units and a CO removing reactors until a CO level lower than 10ppm, that finally feeds a hydrogen fuel stack. (author)

Remarkable nanoconfinement effects on chemical equilibrium manifested in nucleotide dimerization and H-D exchange reactions.

Science.gov (United States)

Polak, Micha; Rubinovich, Leonid

2011-10-06

Nanoconfinement entropic effects on chemical equilibrium involving a small number of molecules, which we term NCECE, are revealed by two widely diverse types of reactions. Employing statistical-mechanical principles, we show how the NCECE effect stabilizes nucleotide dimerization observed within self-assembled molecular cages. Furthermore, the effect provides the basis for dimerization even under an aqueous environment inside the nanocage. Likewise, the NCECE effect is pertinent to a longstanding issue in astrochemistry, namely the extra deuteration commonly observed for molecules reacting on interstellar dust grain surfaces. The origin of the NCECE effect is elucidated by means of the probability distributions of the reaction extent and related variations in the reactant-product mixing entropy. Theoretical modelling beyond our previous preliminary work highlights the role of the nanospace size in addition to that of the nanosystem size, namely the limited amount of molecules in the reaction mixture. Furthermore, the NCECE effect can depend also on the reaction mechanism, and on deviations from stoichiometry. The NCECE effect, leading to enhanced, greatly variable equilibrium "constants", constitutes a unique physical-chemical phenomenon, distinguished from the usual thermodynamical properties of macroscopically large systems. Being significant particularly for weakly exothermic reactions, the effects should stabilize products in other closed nanoscale structures, and thus can have notable implications for the growing nanotechnological utilization of chemical syntheses conducted within confined nanoreactors.

Chemical factors that control lignin polymerization.

Science.gov (United States)

Sangha, Amandeep K; Davison, Brian H; Standaert, Robert F; Davis, Mark F; Smith, Jeremy C; Parks, Jerry M

2014-01-09

Lignin is a complex, branched polymer that reinforces plant tissue. Understanding the factors that govern lignin structure is of central importance to the development of technologies for converting lignocellulosic biomass into fuels because lignin imparts resistance to chemical, enzymatic, and mechanical deconstruction. Lignin is formed by enzymatic oxidation of phenolic monomers (monolignols) of three main types, guaiacyl (G), syringyl (S), and p-hydroxyphenyl (H) subunits. It is known that increasing the relative abundance of H subunits results in lower molecular weight lignin polymers and hence more easily deconstructed biomass, but it is not known why. Here, we report an analysis of frontier molecular orbitals in mono-, di-, and trilignols, calculated using density functional theory, which points to a requirement of strong p-electron density on the reacting phenolic oxygen atom of the neutral precursor for enzymatic oxidation to occur. This model is consistent with a proton-coupled electron transfer (PCET) mechanism and for the first time explains why H subunits in certain linkages (β-β or β-5) react poorly and tend to "cap" the polymer. In general, β-5 linkages with either a G or H terminus are predicted to inhibit elongation. More broadly, the model correctly accounts for the reactivity of the phenolic groups in a diverse set of dilignols comprising H and G subunits. Thus, we provide a coherent framework for understanding the propensity toward growth or termination of different terminal subunits in lignin.

Development and testing of bumper limiter of aluminum alloy vacuum vessel for reacting plasma experiment

International Nuclear Information System (INIS)

Uchikawa, T.; Fujiwara, M.; Ioki, K.; Irie, T.; Nayama, R.; Nishikawa, M.; Onozuka, M.; Tomita, M.

1985-01-01

Two types of graphite bumper limiters were designed and trially fabricated for a reacting plasma device, R-tokamak. High heat load tests were conducted to examine thermal behavior and thermal shock resistance of the limiters by using a 100kW electron beam facility. The experimental data were compared with the results of 3-D thermal analysis

Development and testing of bumper limiter of aluminum alloy vacuum vessel for reacting plasma experiment

Energy Technology Data Exchange (ETDEWEB)

Uchikawa, T.; Fujiwara, M.; Ioki, K.; Irie, T.; Nayama, R.; Nishikawa, M.; Onozuka, M.; Tomita, M.

1985-07-01

Two types of graphite bumper limiters were designed and trially fabricated for a reacting plasma device, R-tokamak. High heat load tests were conducted to examine thermal behavior and thermal shock resistance of the limiters by using a 100kW electron beam facility. The experimental data were compared with the results of 3-D thermal analysis.

A Self-Calibrating Remote Control Chemical Monitoring System

Energy Technology Data Exchange (ETDEWEB)

Jessica Croft

2007-06-01

The Susie Mine, part of the Upper Tenmile Mining Area, is located in Rimini, MT about 15 miles southwest of Helena, MT. The Upper Tenmile Creek Mining Area is an EPA Superfund site with 70 abandoned hard rock mines and several residential yards prioritized for clean up. Water from the Susie mine flows into Tenmile Creek from which the city of Helena draws part of its water supply. MSE Technology Applications in Butte, Montana was contracted by the EPA to build a treatment system for the Susie mine effluent and demonstrate a system capable of treating mine waste water in remote locations. The Idaho National Lab was contracted to design, build and demonstrate a low maintenance self-calibrating monitoring system that would monitor multiple sample points, allow remote two-way communications with the control software and allow access to the collected data through a web site. The Automated Chemical Analysis Monitoring (ACAM) system was installed in December 2006. This thesis documents the overall design of the hardware, control software and website, the data collected while MSE-TA’s system was operational, the data collected after MSE-TA’s system was shut down and suggested improvements to the existing system.

Performance of two swine manure treatment systems on chemical composition and on the reduction of pathogens.

Science.gov (United States)

Viancelli, A; Kunz, A; Steinmetz, R L R; Kich, J D; Souza, C K; Canal, C W; Coldebella, A; Esteves, P A; Barardi, C R M

2013-01-01

Swine effluents must be correctly handled to avoid negative environmental impacts. In this study, the profiles of two swine manure treatment systems were evaluated: a solid-liquid separation step, followed by an anaerobic reactor, and an aerobic step (System 1); and a biodigester followed by serial lagoons (System 2). Both systems were described by the assessment of chemical, bacterial and viral parameters. The results showed that in System 1, there was reduction of chemicals (COD, phosphorus, total Kjeldhal nitrogen - TKN - and NH(3)), total coliforms and Escherichia coli; however, the same reduction was not observed for Salmonella sp. Viral particles were significantly reduced but not totally eliminated from the effluent. In System 2, there was a reduction of chemicals, bacteria and viruses with no detection of Salmonella sp., circovirus, parvovirus, and torque teno virus in the effluent. The chemical results indicate that the treated effluent can be reused for cleaning swine facilities. However, the microbiological results show a need of additional treatment to achieve a complete inactivation for cases when direct contact with animals is required. Copyright © 2012 Elsevier Ltd. All rights reserved.

Simulation and Analysis of Isotope Separation System for Fusion Fuel Recovery System

Science.gov (United States)

Senevirathna, Bathiya; Gentile, Charles

2011-10-01

This paper presents results of a simulation of the Fuel Recovery System (FRS) for the Laser Inertial Fusion Engine (LIFE) reactor. The LIFE reaction will produce exhaust gases that will need to be recycled in the FRS along with xenon, the chamber's intervention gas. Solids and liquids will first be removed and then vapor traps are used to remove large gas molecules such as lead. The gas will be reacted with lithium at high temperatures to extract the hydrogen isotopes, protium, deuterium, and tritium in hydride form. The hydrogen isotopes will be recovered using a lithium blanket processing system already in place and this product will be sent to the Isotope Separation System (ISS). The ISS will be modeled in software to analyze its effectiveness. Aspen HYSYS was chosen for this purpose for its widespread use industrial gas processing systems. Reactants and corresponding chemical reactions had to be initialized in the software. The ISS primarily consists of four cryogenic distillation columns and these were modeled in HYSYS based on design requirements. Fractional compositions of the distillate and liquid products were analyzed and used to optimize the overall system.

Analysis Of Convective Plane Stagnation Point Chemically Reactive Mhd Flow Past A Vertical Porous Plate With A Convective Boundary Condition In The Presence Of A Uniform Magnetic Field.

OpenAIRE

Adeniyan, A.,

2013-01-01

The numerical investigation of a stagnation point boundary layer flow , mass and heat transfer of a steady two dimensional , incompressible , viscous electrically conducting, chemically reacting laminar fluid over a vertical convectively heated , electrically neutral flat plate exposed to a transverse uniform magnetic field has been carried out to examine the influence of the simultaneous presence of the effects of a convective boundary condition, chemical reaction, heat transfer and suctio...

Predictive Modelling of Phase-Transfer Catalyst Systems for Improved and Innovative Design

DEFF Research Database (Denmark)

Anantpinijwatna, Amata; Hyung Kim, Sun; Sales-Cruz, Mauricio

2016-01-01

Phase-transfer catalyst (PTC) systems contain two immiscible liquid phases with a heterogeneous PTC transferring active ion from one phase to the other for converting the reactant to the desired product, and in the process generating the inactive ion. This type of reacting systems is receiving...... increasing attention as a novel organic synthesis option due to its flexible and easier operation, higher production yield, and ability to eliminate expensive solvents, although, not eliminating the use of solvents. New mathematical models of the PTC system, which includes physical and chemical equilibrium......, reaction mechanism and unit operation has been developed. In the developed model, the PTC system is divided into four sub-systems of aqueous-organic solvent partition, inorganic salt in aqueous phase, PTC in aqueous phase, and PTC in aqueous phase. Each subsystem requires an appropriate thermodynamic model...

Chemical sensor system

Science.gov (United States)

Darrach, Murray R. (Inventor); Chutjian, Ara (Inventor)

2008-01-01

A chemical sensing apparatus and method for the detection of sub parts-per-trillion concentrations of molecules in a sample by optimizing electron utilization in the formation of negative ions is provided. A variety of media may be sampled including air, seawater, dry sediment, or undersea sediment. An electrostatic mirror is used to reduce the kinetic energy of an electron beam to zero or near-zero kinetic energy.

Fuel-cladding chemical interaction