WorldWideScience

Sample records for methods included chemical

  1. Aerosol simulation including chemical and nuclear reactions

    International Nuclear Information System (INIS)

    Marwil, E.S.; Lemmon, E.C.

    1985-01-01

    The numerical simulation of aerosol transport, including the effects of chemical and nuclear reactions presents a challenging dynamic accounting problem. Particles of different sizes agglomerate and settle out due to various mechanisms, such as diffusion, diffusiophoresis, thermophoresis, gravitational settling, turbulent acceleration, and centrifugal acceleration. Particles also change size, due to the condensation and evaporation of materials on the particle. Heterogeneous chemical reactions occur at the interface between a particle and the suspending medium, or a surface and the gas in the aerosol. Homogeneous chemical reactions occur within the aersol suspending medium, within a particle, and on a surface. These reactions may include a phase change. Nuclear reactions occur in all locations. These spontaneous transmutations from one element form to another occur at greatly varying rates and may result in phase or chemical changes which complicate the accounting process. This paper presents an approach for inclusion of these effects on the transport of aerosols. The accounting system is very complex and results in a large set of stiff ordinary differential equations (ODEs). The techniques for numerical solution of these ODEs require special attention to achieve their solution in an efficient and affordable manner. 4 refs

  2. Chemical control methods and tools

    Science.gov (United States)

    Steven Manning; James. Miller

    2011-01-01

    After determining the best course of action for control of an invasive plant population, it is important to understand the variety of methods available to the integrated pest management professional. A variety of methods are now widely used in managing invasive plants in natural areas, including chemical, mechanical, and cultural control methods. Once the preferred...

  3. Chemical microreactor and method thereof

    Science.gov (United States)

    Morse, Jeffrey D [Martinez, CA; Jankowski, Alan [Livermore, CA

    2011-08-09

    A method for forming a chemical microreactor includes forming at least one capillary microchannel in a substrate having at least one inlet and at least one outlet, integrating at least one heater into the chemical microreactor, interfacing the capillary microchannel with a liquid chemical reservoir at the inlet of the capillary microchannel, and interfacing the capillary microchannel with a porous membrane near the outlet of the capillary microchannel, the porous membrane being positioned beyond the outlet of the capillary microchannel, wherein the porous membrane has at least one catalyst material imbedded therein.

  4. Chemical decontamination method

    International Nuclear Information System (INIS)

    Nishiwaki, Hitoshi.

    1996-01-01

    Metal wastes contaminated by radioactive materials are contained in a rotational decontamination vessel, and the metal wastes are rotated therein while being in contact with a slight amount of a decontamination liquid comprising a mineral acid. As the mineral acid, a mixed acid of nitric acid, hydrochloric acid and fluoric acid is preferably used. Alternatively, chemical decontamination can also be conducted by charging an acid resistant stirring medium in the rotational decontamination vessel. The surface of the metal wastes is uniformly covered by the slight amount of decontamination liquid to dissolve the surface layer. In addition, heat of dissolution generated in this case is accumulated in the inside of the rotational decontamination vessel, the temperature is elevated with no particular heating, thereby enabling to obtain an excellent decontamination effect substantially at the same level as in the case of heating the liquid to 70degC in a conventional immersion decontamination method. Further, although contact areas between the metal wastes and the immersion vessel are difficult to be decontaminated in the immersion decontamination method, all of areas can be dissolved uniformly in the present invention. (T.M.)

  5. Chemical equilibrium of ablation materials including condensed species

    Science.gov (United States)

    Stroud, C. W.; Brinkley, K. L.

    1975-01-01

    Equilibrium is determined by finding chemical composition with minimum free energy. Method of steepest descent is applied to quadratic representation of free-energy surface. Solution is initiated by selecting arbitrary set of mole fractions, from which point on free-energy surface is computed.

  6. Modeling Electric Double-Layers Including Chemical Reaction Effects

    DEFF Research Database (Denmark)

    Paz-Garcia, Juan Manuel; Johannesson, Björn; Ottosen, Lisbeth M.

    2014-01-01

    A physicochemical and numerical model for the transient formation of an electric double-layer between an electrolyte and a chemically-active flat surface is presented, based on a finite elements integration of the nonlinear Nernst-Planck-Poisson model including chemical reactions. The model works...... for symmetric and asymmetric multi-species electrolytes and is not limited to a range of surface potentials. Numerical simulations are presented, for the case of a CaCO3 electrolyte solution in contact with a surface with rate-controlled protonation/deprotonation reactions. The surface charge and potential...... are determined by the surface reactions, and therefore they depends on the bulk solution composition and concentration...

  7. Designing monitoring programs for chemicals of emerging concern in potable reuse ⋯ What to include and what not to include?

    KAUST Repository

    Drewes, Jorg; Anderson, Paul D.; Denslow, Nancy D.; Olivieri, Adam W.; Schlenk, Daniel K.; Snyder, Shane A.; Maruya, Keith

    2012-01-01

    This study discussed a proposed process to prioritize chemicals for reclaimed water monitoring programs, selection of analytical methods required for their quantification, toxicological relevance of chemicals of emerging concern regarding human health, and related issues. Given that thousands of chemicals are potentially present in reclaimed water and that information about those chemicals is rapidly evolving, a transparent, science-based framework was developed to guide prioritization of which compounds of emerging concern (CECs) should be included in reclaimed water monitoring programs. The recommended framework includes four steps: (1) compile environmental concentrations (e.g., measured environmental concentration or MEC) of CECs in the source water for reuse projects; (2) develop a monitoring trigger level (MTL) for each of these compounds (or groups thereof) based on toxicological relevance; (3) compare the environmental concentration (e.g., MEC) to the MTL; CECs with a MEC/MTL ratio greater than 1 should be prioritized for monitoring, compounds with a ratio less than '1' should only be considered if they represent viable treatment process performance indicators; and (4) screen the priority list to ensure that a commercially available robust analytical method is available for that compound. © IWA Publishing 2013.

  8. Designing monitoring programs for chemicals of emerging concern in potable reuse--what to include and what not to include?

    Science.gov (United States)

    Drewes, J E; Anderson, P; Denslow, N; Olivieri, A; Schlenk, D; Snyder, S A; Maruya, K A

    2013-01-01

    This study discussed a proposed process to prioritize chemicals for reclaimed water monitoring programs, selection of analytical methods required for their quantification, toxicological relevance of chemicals of emerging concern regarding human health, and related issues. Given that thousands of chemicals are potentially present in reclaimed water and that information about those chemicals is rapidly evolving, a transparent, science-based framework was developed to guide prioritization of which compounds of emerging concern (CECs) should be included in reclaimed water monitoring programs. The recommended framework includes four steps: (1) compile environmental concentrations (e.g., measured environmental concentration or MEC) of CECs in the source water for reuse projects; (2) develop a monitoring trigger level (MTL) for each of these compounds (or groups thereof) based on toxicological relevance; (3) compare the environmental concentration (e.g., MEC) to the MTL; CECs with a MEC/MTL ratio greater than 1 should be prioritized for monitoring, compounds with a ratio less than '1' should only be considered if they represent viable treatment process performance indicators; and (4) screen the priority list to ensure that a commercially available robust analytical method is available for that compound.

  9. Designing monitoring programs for chemicals of emerging concern in potable reuse ⋯ What to include and what not to include?

    KAUST Repository

    Drewes, Jorg

    2012-11-01

    This study discussed a proposed process to prioritize chemicals for reclaimed water monitoring programs, selection of analytical methods required for their quantification, toxicological relevance of chemicals of emerging concern regarding human health, and related issues. Given that thousands of chemicals are potentially present in reclaimed water and that information about those chemicals is rapidly evolving, a transparent, science-based framework was developed to guide prioritization of which compounds of emerging concern (CECs) should be included in reclaimed water monitoring programs. The recommended framework includes four steps: (1) compile environmental concentrations (e.g., measured environmental concentration or MEC) of CECs in the source water for reuse projects; (2) develop a monitoring trigger level (MTL) for each of these compounds (or groups thereof) based on toxicological relevance; (3) compare the environmental concentration (e.g., MEC) to the MTL; CECs with a MEC/MTL ratio greater than 1 should be prioritized for monitoring, compounds with a ratio less than \\'1\\' should only be considered if they represent viable treatment process performance indicators; and (4) screen the priority list to ensure that a commercially available robust analytical method is available for that compound. © IWA Publishing 2013.

  10. The role of chemical engineering in medicinal research including Alzheimer's.

    Science.gov (United States)

    Kontogeorgis, Georgios M

    2015-01-01

    Various disciplines of chemical engineering, especially thermodynamics and kinetics, play an important role in medicinal research and this has been particularly recognized during the last 10-15 years (von Stockar and van der Wielen, J Biotechnol 59:25, 1997; Prausnitz, Fluid Phase Equilib 53:439, 1989; Prausnitz, Pure Appl Chem 79:1435, 2007; Dey and Prausnitz, Ind Eng Chem Res 50:3, 2011; Prausnitz, J Chem Thermodynamics 35:21, 2003; Tsivintzelis et al. AIChE J 55:756, 2009). It is expected that during the twenty-first century chemical engineering and especially thermodynamics can contribute as significantly to the life sciences development as it has been done with the oil and gas and chemical sectors in the twentieth century. Moreover, it has during the recent years recognized that thermodynamics can help in understanding diseases like human cataract, sickle-cell anemia, Creuzfeldt-Jacob ("mad cow" disease), and Alzheimer's which are connected to "protein aggregation." Several articles in the Perspectives section of prominent chemical engineering journals have addressed this issue (Hall, AIChE J 54:1956, 2008; Vekilov, AIChE J 54:2508, 2008). This work reviews recent applications of thermodynamics (and other areas of chemical engineering) first in drug development and then in the understanding of the mechanism of Alzheimer's and similar diseases.

  11. Chemical methods of rock analysis

    National Research Council Canada - National Science Library

    Jeffery, P. G; Hutchison, D

    1981-01-01

    .... Such methods include those based upon spectrophotometry, flame emission spectrometry and atomic absorption spectroscopy, as well as gravimetry, titrimetry and the use of ion-selective electrodes...

  12. Chemical composition of planetary nebulae : Including ISO results

    NARCIS (Netherlands)

    Pottasch, [No Value; Beintema, DA; Salas, JB; Feibelman, WA; Henney, WJ; Franco, J; Martos, M; Pena, M

    2002-01-01

    The method of determining abundances using Infrared Space Observatory spectra is discussed. The results for seven planetary nebula are given. Using these data, a preliminary discussion of their evolution is given.

  13. Heat Diffusion in Gases, Including Effects of Chemical Reaction

    Science.gov (United States)

    Hansen, C. Frederick

    1960-01-01

    The diffusion of heat through gases is treated where the coefficients of thermal conductivity and diffusivity are functions of temperature. The diffusivity is taken proportional to the integral of thermal conductivity, where the gas is ideal, and is considered constant over the temperature interval in which a chemical reaction occurs. The heat diffusion equation is then solved numerically for a semi-infinite gas medium with constant initial and boundary conditions. These solutions are in a dimensionless form applicable to gases in general, and they are used, along with measured shock velocity and heat flux through a shock reflecting surface, to evaluate the integral of thermal conductivity for air up to 5000 degrees Kelvin. This integral has the properties of a heat flux potential and replaces temperature as the dependent variable for problems of heat diffusion in media with variable coefficients. Examples are given in which the heat flux at the stagnation region of blunt hypersonic bodies is expressed in terms of this potential.

  14. Finite element modeling of contaminant transport in soils including the effect of chemical reactions.

    Science.gov (United States)

    Javadi, A A; Al-Najjar, M M

    2007-05-17

    The movement of chemicals through soils to the groundwater is a major cause of degradation of water resources. In many cases, serious human and stock health implications are associated with this form of pollution. Recent studies have shown that the current models and methods are not able to adequately describe the leaching of nutrients through soils, often underestimating the risk of groundwater contamination by surface-applied chemicals, and overestimating the concentration of resident solutes. Furthermore, the effect of chemical reactions on the fate and transport of contaminants is not included in many of the existing numerical models for contaminant transport. In this paper a numerical model is presented for simulation of the flow of water and air and contaminant transport through unsaturated soils with the main focus being on the effects of chemical reactions. The governing equations of miscible contaminant transport including advection, dispersion-diffusion and adsorption effects together with the effect of chemical reactions are presented. The mathematical framework and the numerical implementation of the model are described in detail. The model is validated by application to a number of test cases from the literature and is then applied to the simulation of a physical model test involving transport of contaminants in a block of soil with particular reference to the effects of chemical reactions. Comparison of the results of the numerical model with the experimental results shows that the model is capable of predicting the effects of chemical reactions with very high accuracy. The importance of consideration of the effects of chemical reactions is highlighted.

  15. 75 FR 9437 - Wacker Chemical Corporation Wacker Polymers Division a Subsidiary of Wacker Chemie AG Including...

    Science.gov (United States)

    2010-03-02

    ... Chemical Corporation Wacker Polymers Division a Subsidiary of Wacker Chemie AG Including On-Site Leased.... and Yoh Managed Staffing South Brunswick, NJ; Wacker Chemical Corporation Wacker Polymers Division a... of Wacker Chemical Corporation, Wacker Polymers Division, a subsidiary of Wacker Chemie AG, including...

  16. Chemical Tracer Methods: Chapter 7

    Science.gov (United States)

    Healy, Richard W.

    2017-01-01

    Tracers have a wide variety of uses in hydrologic studies: providing quantitative or qualitative estimates of recharge, identifying sources of recharge, providing information on velocities and travel times of water movement, assessing the importance of preferential flow paths, providing information on hydrodynamic dispersion, and providing data for calibration of water flow and solute-transport models (Walker, 1998; Cook and Herczeg, 2000; Scanlon et al., 2002b). Tracers generally are ions, isotopes, or gases that move with water and that can be detected in the atmosphere, in surface waters, and in the subsurface. Heat also is transported by water; therefore, temperatures can be used to trace water movement. This chapter focuses on the use of chemical and isotopic tracers in the subsurface to estimate recharge. Tracer use in surface-water studies to determine groundwater discharge to streams is addressed in Chapter 4; the use of temperature as a tracer is described in Chapter 8.Following the nomenclature of Scanlon et al. (2002b), tracers are grouped into three categories: natural environmental tracers, historical tracers, and applied tracers. Natural environmental tracers are those that are transported to or created within the atmosphere under natural processes; these tracers are carried to the Earth’s surface as wet or dry atmospheric deposition. The most commonly used natural environmental tracer is chloride (Cl) (Allison and Hughes, 1978). Ocean water, through the process of evaporation, is the primary source of atmospheric Cl. Other tracers in this category include chlorine-36 (36Cl) and tritium (3H); these two isotopes are produced naturally in the Earth’s atmosphere; however, there are additional anthropogenic sources of them.

  17. Catalyst support structure, catalyst including the structure, reactor including a catalyst, and methods of forming same

    Science.gov (United States)

    Van Norman, Staci A.; Aston, Victoria J.; Weimer, Alan W.

    2017-05-09

    Structures, catalysts, and reactors suitable for use for a variety of applications, including gas-to-liquid and coal-to-liquid processes and methods of forming the structures, catalysts, and reactors are disclosed. The catalyst material can be deposited onto an inner wall of a microtubular reactor and/or onto porous tungsten support structures using atomic layer deposition techniques.

  18. 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.

  19. Composite material including nanocrystals and methods of making

    Science.gov (United States)

    Bawendi, Moungi G.; Sundar, Vikram C.

    2010-04-06

    Temperature-sensing compositions can include an inorganic material, such as a semiconductor nanocrystal. The nanocrystal can be a dependable and accurate indicator of temperature. The intensity of emission of the nanocrystal varies with temperature and can be highly sensitive to surface temperature. The nanocrystals can be processed with a binder to form a matrix, which can be varied by altering the chemical nature of the surface of the nanocrystal. A nanocrystal with a compatibilizing outer layer can be incorporated into a coating formulation and retain its temperature sensitive emissive properties.

  20. Device for collecting chemical compounds and related methods

    Science.gov (United States)

    Scott, Jill R.; Groenewold, Gary S.; Rae, Catherine

    2013-01-01

    A device for sampling chemical compounds from fixed surfaces and related methods are disclosed. The device may include a vacuum source, a chamber and a sorbent material. The device may utilize vacuum extraction to volatilize the chemical compounds from the fixed surfaces so that they may be sorbed by the sorbent material. The sorbent material may then be analyzed using conventional thermal desorption/gas chromatography/mass spectrometry (TD/GC/MS) instrumentation to determine presence of the chemical compounds. The methods may include detecting release and presence of one or more chemical compounds and determining the efficacy of decontamination. The device may be useful in collection and analysis of a variety of chemical compounds, such as residual chemical warfare agents, chemical attribution signatures and toxic industrial chemicals.

  1. Microfluidic devices and methods including porous polymer monoliths

    Science.gov (United States)

    Hatch, Anson V; Sommer, Gregory J; Singh, Anup K; Wang, Ying-Chih; Abhyankar, Vinay V

    2014-04-22

    Microfluidic devices and methods including porous polymer monoliths are described. Polymerization techniques may be used to generate porous polymer monoliths having pores defined by a liquid component of a fluid mixture. The fluid mixture may contain iniferters and the resulting porous polymer monolith may include surfaces terminated with iniferter species. Capture molecules may then be grafted to the monolith pores.

  2. Methods of producing adsorption media including a metal oxide

    Science.gov (United States)

    Mann, Nicholas R; Tranter, Troy J

    2014-03-04

    Methods of producing a metal oxide are disclosed. The method comprises dissolving a metal salt in a reaction solvent to form a metal salt/reaction solvent solution. The metal salt is converted to a metal oxide and a caustic solution is added to the metal oxide/reaction solvent solution to adjust the pH of the metal oxide/reaction solvent solution to less than approximately 7.0. The metal oxide is precipitated and recovered. A method of producing adsorption media including the metal oxide is also disclosed, as is a precursor of an active component including particles of a metal oxide.

  3. Survey of Nuclear Methods in Chemical Technology

    International Nuclear Information System (INIS)

    Broda, E.

    1966-01-01

    An attempt is made to classify nuclear methods on a logical basis to facilitate assimilation by the technologist. The three main groups are: (I) Tracer methods, (II) Methods based on the influence of absorbers on radiations to be measured, and (III) Radiation chemical methods. The variants of the first two groups are discussed in some detail, and typical examples are given. Group I can be subdivided into (1) Indicator methods, (2) Emanation methods, (3) Radioreagent methods, and (4) Isotope dilution methods, Group II into (5) Activation methods, (6) Absorption methods, (7) Induced Nuclear Reaction methods, (8) Scattering methods, and (9) Fluorescence methods. While the economic benefits due to nuclear methods already run into hundreds of millions of dollars annually, owing to radiation protection problems radiochemical methods in the strict sense are not widely used in actual production. It is suggested that more use should be made of pilot plant tracer studies of chemical processes as used in industry. (author)

  4. Chemical methods of rock analysis

    National Research Council Canada - National Science Library

    Jeffery, P. G; Hutchison, D

    1981-01-01

    A practical guide to the methods in general use for the complete analysis of silicate rock material and for the determination of all those elements present in major, minor or trace amounts in silicate...

  5. 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.

  6. Unsteady panel method for complex configurations including wake modeling

    CSIR Research Space (South Africa)

    Van Zyl, Lourens H

    2008-01-01

    Full Text Available implementations of the DLM are however not very versatile in terms of geometries that can be modeled. The ZONA6 code offers a versatile surface panel body model including a separated wake model, but uses a pressure panel method for lifting surfaces. This paper...

  7. Initiation devices, initiation systems including initiation devices and related methods

    Energy Technology Data Exchange (ETDEWEB)

    Daniels, Michael A.; Condit, Reston A.; Rasmussen, Nikki; Wallace, Ronald S.

    2018-04-10

    Initiation devices may include at least one substrate, an initiation element positioned on a first side of the at least one substrate, and a spark gap electrically coupled to the initiation element and positioned on a second side of the at least one substrate. Initiation devices may include a plurality of substrates where at least one substrate of the plurality of substrates is electrically connected to at least one adjacent substrate of the plurality of substrates with at least one via extending through the at least one substrate. Initiation systems may include such initiation devices. Methods of igniting energetic materials include passing a current through a spark gap formed on at least one substrate of the initiation device, passing the current through at least one via formed through the at least one substrate, and passing the current through an explosive bridge wire of the initiation device.

  8. Comparison of Chemical and Physical-chemical Wastewater Discoloring Methods

    Directory of Open Access Journals (Sweden)

    Durašević, V.

    2007-11-01

    Full Text Available Today's chemical and physical-chemical wastewater discoloration methods do not completely meet demands regarding degree of discoloration. In this paper discoloration was performed using Fenton (FeSO4 . 7 H2O + H2O2 + H2SO4 and Fenton-like (FeCl3 . 6 H2O + H2O2 + HCOOH chemical methods and physical-chemical method of coagulation/flocculation (using poly-electrolyte (POEL combining anion active coagulant (modified poly-acrylamides and cationic flocculant (product of nitrogen compounds in combination with adsorption on activated carbon. Suitability of aforementioned methods was investigated on reactive and acid dyes, regarding their most common use in the textile industry. Also, investigations on dyes of different chromogen (anthraquinone, phthalocyanine, azo and xanthene were carried out in order to determine the importance of molecular spatial structure. Oxidative effect of Fenton and Fenton-like reagents resulted in decomposition of colored chromogen and high degree of discoloration. However, the problem is the inability of adding POEL in stechiometrical ratio (also present in physical-chemical methods, when the phenomenon of overdosing coagulants occurs in order to obtain a higher degree of discoloration, creating a potential danger of burdening water with POEL. Input and output water quality was controlled through spectrophotometric measurements and standard biological parameters. In addition, part of the investigations concerned industrial wastewaters obtained from dyeing cotton materials using reactive dye (C. I. Reactive Blue 19, a process that demands the use of vast amounts of electrolytes. Also, investigations of industrial wastewaters was labeled as a crucial step carried out in order to avoid serious misassumptions and false conclusions, which may arise if dyeing processes are only simulated in the laboratory.

  9. Chemical Methods for Peptide and Protein Production

    Directory of Open Access Journals (Sweden)

    Istvan Toth

    2013-04-01

    Full Text Available Since the invention of solid phase synthetic methods by Merrifield in 1963, the number of research groups focusing on peptide synthesis has grown exponentially. However, the original step-by-step synthesis had limitations: the purity of the final product decreased with the number of coupling steps. After the development of Boc and Fmoc protecting groups, novel amino acid protecting groups and new techniques were introduced to provide high quality and quantity peptide products. Fragment condensation was a popular method for peptide production in the 1980s, but unfortunately the rate of racemization and reaction difficulties proved less than ideal. Kent and co-workers revolutionized peptide coupling by introducing the chemoselective reaction of unprotected peptides, called native chemical ligation. Subsequently, research has focused on the development of novel ligating techniques including the famous click reaction, ligation of peptide hydrazides, and the recently reported a-ketoacid-hydroxylamine ligations with 5-oxaproline. Several companies have been formed all over the world to prepare high quality Good Manufacturing Practice peptide products on a multi-kilogram scale. This review describes the advances in peptide chemistry including the variety of synthetic peptide methods currently available and the broad application of peptides in medicinal chemistry.

  10. Chemical methods for peptide and protein production.

    Science.gov (United States)

    Chandrudu, Saranya; Simerska, Pavla; Toth, Istvan

    2013-04-12

    Since the invention of solid phase synthetic methods by Merrifield in 1963, the number of research groups focusing on peptide synthesis has grown exponentially. However, the original step-by-step synthesis had limitations: the purity of the final product decreased with the number of coupling steps. After the development of Boc and Fmoc protecting groups, novel amino acid protecting groups and new techniques were introduced to provide high quality and quantity peptide products. Fragment condensation was a popular method for peptide production in the 1980s, but unfortunately the rate of racemization and reaction difficulties proved less than ideal. Kent and co-workers revolutionized peptide coupling by introducing the chemoselective reaction of unprotected peptides, called native chemical ligation. Subsequently, research has focused on the development of novel ligating techniques including the famous click reaction, ligation of peptide hydrazides, and the recently reported α-ketoacid-hydroxylamine ligations with 5-oxaproline. Several companies have been formed all over the world to prepare high quality Good Manufacturing Practice peptide products on a multi-kilogram scale. This review describes the advances in peptide chemistry including the variety of synthetic peptide methods currently available and the broad application of peptides in medicinal chemistry.

  11. Spectroscopic Chemical Analysis Methods and Apparatus

    Science.gov (United States)

    Hug, William F. (Inventor); Reid, Ray D. (Inventor); Bhartia, Rohit (Inventor); Lane, Arthur L. (Inventor)

    2018-01-01

    Spectroscopic chemical analysis methods and apparatus are disclosed which employ deep ultraviolet (e.g. in the 200 nm to 300 nm spectral range) electron beam pumped wide bandgap semiconductor lasers, incoherent wide bandgap semiconductor light emitting devices, and hollow cathode metal ion lasers to perform non-contact, non-invasive detection of unknown chemical analytes. These deep ultraviolet sources enable dramatic size, weight and power consumption reductions of chemical analysis instruments. In some embodiments, Raman spectroscopic detection methods and apparatus use ultra-narrow-band angle tuning filters, acousto-optic tuning filters, and temperature tuned filters to enable ultra-miniature analyzers for chemical identification. In some embodiments Raman analysis is conducted along with photoluminescence spectroscopy (i.e. fluorescence and/or phosphorescence spectroscopy) to provide high levels of sensitivity and specificity in the same instrument.

  12. Including chemical-related impact categories in LCA on printed matter does it matter?

    DEFF Research Database (Denmark)

    Larsen, Henrik Fred; Hansen, Morten Søes; Hauschild, Michael Zwicky

    2004-01-01

    global warming, acidification and nutrification. The studies focus on energy consumption including the emissions and impact categories related to energy. The chemical-related impact categories comprising ecotoxicity and human toxicity are not included at all or only to a limited degree. In this paper we...... include these chemical-related impact categories by making use of some of the newest knowledge about emissions from the production at the printing industry combined with knowledge about the composition of the printing materials used during the production of offset printed matter. This paper is based...... printed matter produced on a fictitious sheet feed offset printing industry in Europe has been identified and shown in Figure 1 (light bars). „Ï The effect of including the chemical related impact categories is substantial as shown in Figure 1, e.g. the importance of paper is reduced from 67% to 31...

  13. VBSCF Methods: Classical Chemical Concepts and Beyond

    NARCIS (Netherlands)

    Rashid, Z.

    2013-01-01

    The aim of this research has been to extend the ab initio Valence Bond Self-Consistent Field (VBSCF) methodology and to apply this method to the electronic structure of molecules. The valence bond method directly deals with the chemical structure of molecules in a pictorial language, which chemists

  14. Chemical decontaminating method for stainless steel

    International Nuclear Information System (INIS)

    Onuma, Tsutomu; Akimoto, Hidetoshi.

    1990-01-01

    Radioactive metal wastes comprising passivated stainless steels are chemically decontaminated to such a radioactivity level as that of usual wastes. The present invention for chemically decontaminating stainless steels comprises a first step of immersing decontaminates into a sulfuric acid solution and a second step of immersing them into an aqueous solution prepared by adding oxidative metal salts to sulfuric acid, in which a portion of the surface of stainless steels as decontaminates are chemically ground to partially expose substrate materials and then the above-mentioned decontamination steps are applied. More than 90% of radioactive materials are removed in this method by the dissolution of the exposed substrate materials and peeling of cruds secured to the surface of the materials upon dissolution. This method is applicable to decontamination of articles having complicate shapes, can reduce the amount of secondary wastes after decontamination and also remarkably shorten the time required for decontamination. (T.M.)

  15. Impact of supersonic and subsonic aircraft on ozone: Including heterogeneous chemical reaction mechanisms

    International Nuclear Information System (INIS)

    Kinnison, D.E.; Wuebbles, D.J.

    1992-01-01

    Preliminary calculations suggest that heterogeneous reactions are important in calculating the impact on ozone from emissions of trace gases from aircraft fleets. In this study, three heterogeneous chemical processes that occur on background sulfuric acid aerosols are included and their effects on O 3 , NO x , Cl x , HCl, N 2 O 5 , ClONO 2 are calculated

  16. Mass spectrometry in identification of ecotoxicants including chemical and biological warfare agents

    International Nuclear Information System (INIS)

    Lebedev, Albert T.

    2005-01-01

    Mass spectrometry is a unique tool to detect and identify trace levels of organic and bioorganic compounds as well as microorganisms in the environment. The range of potential chemical warfare (CW) and biological warfare (BW) agents is very broad. An important advantage of mass spectrometry over other techniques involves potential for full spectrum detection of chemical and biological agents including mid-spectrum materials (i.e. bioactive peptides, toxins, etc.) for which biological approaches are inadequate. Being very fast (seconds and minutes), extremely sensitive (zeptomoles 10 -21 ), and informative (detailed qualitative and quantitative composition of mixtures containing hundreds of chemicals), mass spectrometry is a principal analytical tool at the sites of destruction of CW. Due to its unique features, mass spectrometry is applied not only for the detection of CW agents, but for the analysis of products of metabolism and degradation of these agents in organisms or environment as well. The present paper deals with some examples of successful application of mass spectrometry for the analyses of ecotoxicants, chemical warfare agents, explosives, and microorganisms including biology warfare agents

  17. A FILTRATION METHOD AND APPARATUS INCLUDING A ROLLER WITH PORES

    DEFF Research Database (Denmark)

    2008-01-01

    The present invention offers a method for separating dry matter from a medium. A separation chamber is at least partly defined by a plurality of rollers (2,7) and is capable of being pressure regulated. At least one of the rollers is a pore roller (7) having a surface with pores allowing permeabi...

  18. Chemically reducing decontamination method for radioactive metal

    International Nuclear Information System (INIS)

    Tanaka, Akio; Onuma, Tsutomu; Sato, Hitoshi.

    1994-01-01

    The present invention concerns a decontamination method of electrolytically reducing radioactive metal wastes, then chemically dissolving the surface thereof with a strong acid decontaminating solution. This method utilizes dissolving characteristics of stainless steels in the strong acid solution. That is, in the electrolytic reduction operation, a portion of the metal wastes is brought into contact with a strong acid decontaminating solution, and voltage and current are applied to the portion and keep it for a long period of time so as to make the potential of the immersed portion of the metal wastes to an active soluble region. Then, the electrolytic reduction operation is stopped, and the metal wastes are entirely immersed in the decontaminating solution to decontaminate by chemical dissolution. As the decontaminating solution, strong acid such as sulfuric acid, nitric acid is used. Since DC current power source capacity required for causing reaction in the active soluble region can be decreased, the decontamination facility can be minimized and simplified, and necessary electric power can be saved even upon decontamination of radioactive metal wastes made of stainless steels and having a great area. Further, chemical dissolution can be conducted without adding an expensive oxidizing agent. (N.H.)

  19. Chemical Methods to Knock Down the Amyloid Proteins

    Directory of Open Access Journals (Sweden)

    Na Gao

    2017-06-01

    Full Text Available Amyloid proteins are closely related with amyloid diseases and do tremendous harm to human health. However, there is still a lack of effective strategies to treat these amyloid diseases, so it is important to develop novel methods. Accelerating the clearance of amyloid proteins is a favorable method for amyloid disease treatment. Recently, chemical methods for protein reduction have been developed and have attracted much attention. In this review, we focus on the latest progress of chemical methods that knock down amyloid proteins, including the proteolysis-targeting chimera (PROTAC strategy, the “recognition-cleavage” strategy, the chaperone-mediated autophagy (CMA strategy, the selectively light-activatable organic and inorganic molecules strategy and other chemical strategies.

  20. Methods for forming complex oxidation reaction products including superconducting articles

    International Nuclear Information System (INIS)

    Rapp, R.A.; Urquhart, A.W.; Nagelberg, A.S.; Newkirk, M.S.

    1992-01-01

    This patent describes a method for producing a superconducting complex oxidation reaction product of two or more metals in an oxidized state. It comprises positioning at least one parent metal source comprising one of the metals adjacent to a permeable mass comprising at least one metal-containing compound capable of reaction to form the complex oxidation reaction product in step below, the metal component of the at least one metal-containing compound comprising at least a second of the two or more metals, and orienting the parent metal source and the permeable mass relative to each other so that formation of the complex oxidation reaction product will occur in a direction towards and into the permeable mass; and heating the parent metal source in the presence of an oxidant to a temperature region above its melting point to form a body of molten parent metal to permit infiltration and reaction of the molten parent metal into the permeable mass and with the oxidant and the at least one metal-containing compound to form the complex oxidation reaction product, and progressively drawing the molten parent metal source through the complex oxidation reaction product towards the oxidant and towards and into the adjacent permeable mass so that fresh complex oxidation reaction product continues to form within the permeable mass; and recovering the resulting complex oxidation reaction product

  1. Chemical analysis by nuclear methods. v. 2

    International Nuclear Information System (INIS)

    Alfassi, Z.B.

    1998-01-01

    'Chemical analysis by Nuclear Methods' is an effort of some renowned authors in field of nuclear chemistry and radiochemistry which is compiled by Alfassi, Z.B. and translated into Farsi version collected in two volumes. The second volume consists of the following chapters: Detecting ion recoil scattering and elastic scattering are dealt in the eleventh chapter, the twelfth chapter is devoted to nuclear reaction analysis using charged particles, X-ray emission is discussed at thirteenth chapter, the fourteenth chapter is about using ion microprobes, X-ray fluorescence analysis is discussed in the fifteenth chapter, alpha, beta and gamma ray scattering in chemical analysis are dealt in chapter sixteen, Moessbauer spectroscopy and positron annihilation are discussed in chapter seventeen and eighteen; The last two chapters are about isotope dilution analysis and radioimmunoassay

  2. Membrane for distillation including nanostructures, methods of making membranes, and methods of desalination and separation

    KAUST Repository

    Lai, Zhiping; Huang, Kuo-Wei; Chen, Wei

    2016-01-01

    In accordance with the purpose(s) of the present disclosure, as embodied and broadly described herein, embodiments of the present disclosure provide membranes, methods of making the membrane, systems including the membrane, methods of separation, methods of desalination, and the like.

  3. Membrane for distillation including nanostructures, methods of making membranes, and methods of desalination and separation

    KAUST Repository

    Lai, Zhiping

    2016-01-21

    In accordance with the purpose(s) of the present disclosure, as embodied and broadly described herein, embodiments of the present disclosure provide membranes, methods of making the membrane, systems including the membrane, methods of separation, methods of desalination, and the like.

  4. Include dispersion in quantum chemical modeling of enzymatic reactions: the case of isoaspartyl dipeptidase.

    Science.gov (United States)

    Zhang, Hai-Mei; Chen, Shi-Lu

    2015-06-09

    The lack of dispersion in the B3LYP functional has been proposed to be the main origin of big errors in quantum chemical modeling of a few enzymes and transition metal complexes. In this work, the essential dispersion effects that affect quantum chemical modeling are investigated. With binuclear zinc isoaspartyl dipeptidase (IAD) as an example, dispersion is included in the modeling of enzymatic reactions by two different procedures, i.e., (i) geometry optimizations followed by single-point calculations of dispersion (approach I) and (ii) the inclusion of dispersion throughout geometry optimization and energy evaluation (approach II). Based on a 169-atom chemical model, the calculations show a qualitative consistency between approaches I and II in energetics and most key geometries, demonstrating that both approaches are available with the latter preferential since both geometry and energy are dispersion-corrected in approach II. When a smaller model without Arg233 (147 atoms) was used, an inconsistency was observed, indicating that the missing dispersion interactions are essentially responsible for determining equilibrium geometries. Other technical issues and mechanistic characteristics of IAD are also discussed, in particular with respect to the effects of Arg233.

  5. Method of chemical decontamination of stainless steel

    International Nuclear Information System (INIS)

    Onuma, Tsutomu; Akimoto, Hidetoshi.

    1989-01-01

    The present invention concerns a decontamination method of chemically decontaminating radioactive metal wastes of passivated stainless steels to a radioactivity level identical with usual wastes, in which the amount of oxidizable metal salts used is decreased. Metal wastes of stainless steels contaminated at their surface with radioactive materials are immersed in a sulfuric acid solution. In this case, a voltage is applied for a certain period of time so that the potential of the stainless steels comes to an active region. Then, oxidizable metal salt (tetravalent cerium) is added into the sulfuric acid solution. According to this method, since most of radioactive materials are removed in the immersing step to the sulfuric acid solution, the amount of the tetravalent cerium used is as less as 1/700 and the decontamination time is as short as 1/4 as compared with those in the conventional method. (K.M.)

  6. Chemical Reactivity as Described by Quantum Chemical Methods

    Directory of Open Access Journals (Sweden)

    F. De Proft

    2002-04-01

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

  7. Chemical decontamination method for radioactive metal waste

    International Nuclear Information System (INIS)

    Tanaka, Akio; Onuma, Tsutomu; Yamazaki, Sei; Miura, Haruki.

    1993-01-01

    The present invention provides a chemical decontamination method for radioactive metal wastes, which are generated from radioactive material handling facilities and the surfaces of which are contaminated by radioactive materials. That is, it has a feature of applying acid dissolution simultaneously with mechanical grinding. The radioactive metal wastes are contained in a vessel such as a barrel together with abrasives in a sulfuric acid solution and rotated at several tens rotation per minute. By such procedures for the radioactive metal wastes, (1) cruds and passive membranes are mechanically removed, (2) exposed mother metal materials are uniformly brought into contact with sulfuric acid and further (3) the mother metal materials dissolve the cruds and the passive membranes also chemically by a reducing dissolution (so-called local cell effect). According to the method of the present invention, stainless steel metal wastes having cruds and passive membranes can rapidly and efficiently be decontaminated to a radiation level equal with that of ordinary wastes. (I.S.)

  8. Chemical countermeasures: Dispersants overview of dispersant use (including application) and research issues

    International Nuclear Information System (INIS)

    Butler, J.N.

    1992-01-01

    I will attempt in twenty minutes to summarize the state of research on oil spill dispersants as I perceive it. The expertise I bring to this task includes 20 years of experience with the fate and effects of petroleum in the marine environment, including participation in the 1973 and 1981 NRC studies and three years as chairman of the NRC committee on oil spill dispersants. I More recently I served on a committee of the International Maritime Organization which reviewed the open-quotes Impact of oil and related chemicals and wastes on the marine environment.close quotes That report will be published this year. However, my statements in this paper are not made as a representative of either NRC or IMO. They are my own interpretation of scientific literature cited in the above reviews. Dispersants are chemical formulations, which include surface active agents, designed to decrease the interfacial tension between oil and water. Because the first attempts to disperse oil on a large scale, at the Torrey Canyon spill of 1967, used highly toxic degreasing agents, dispersants have an undeserved reputation for toxicity. In fact, for twenty years dispersant formulations have been developed with an emphasis on reducing their toxicity to marine life. The dispersal of oil in water has been documented in the laboratory by dozens of papers (see references in NRC 1989, pp 70-79), and in the field by dozens of studies (NRC 1989, pp 165- 193). The toxicity of commercial dispersant formulations (NRC 1989, pp 81-123) and dispersed oil (NRC 1989, pp 123-147) has been tested on a wide variety of marine organisms ranging from algae to salmonid fishes. The NRC review has been updated by the IMO/GESAMP (1992) study, but the conclusions remain unchanged

  9. Chemical compositions, methods of making the chemical compositions, and structures made from the chemical compositions

    Science.gov (United States)

    Yang, Lei; Cheng, Zhe; Liu, Ze; Liu, Meilin

    2015-01-13

    Embodiments of the present disclosure include chemical compositions, structures, anodes, cathodes, electrolytes for solid oxide fuel cells, solid oxide fuel cells, fuel cells, fuel cell membranes, separation membranes, catalytic membranes, sensors, coatings for electrolytes, electrodes, membranes, and catalysts, and the like, are disclosed.

  10. Chemical Compounds and Extraction Methods of "Maollahm".

    Science.gov (United States)

    Sadeghpoor, Omid; Dayeni, Manijeh; Razi, Samane

    2016-05-01

    Maollahm or meat juice, a by-product of meat, is a traditional remedy in Persian medicine. This product was used as a nourishment or treatment substance for sick people. According to the ancient Persian medicine, animal meat has more affinity with the human body and the body easily absorbs its nutrition. Therefore, one could resort to maollahm for patients requiring urgent nourishment to boost and strengthen their body. In this work, different ways of preparing maollahm from poultry, goat, cow, and sheep meat are studied. Most of these methods are based on distillation or barbecue before distillation, as prescribed by traditional medicine books. The reactions, chemical processes, and volatile compounds related to different types of cooked meat are also compared with the outcome of recent research studies. The difference between various types of meat is related to their compounds. Different cooking processes such as barbecuing, roasting, cooking, and boiling have an effect on the taste, smell and the chemical constituents of maollahm. Additionally, the type of meat, animal feed, as well as using or removing the fat during the cooking process, have an effect on the produced volatile compounds. Cooking process and the type of meat have a direct effect on the compounds of maollahm. Possible reactions in the preparation process of maollahm are investigated and presented according to the new research studies.

  11. Fast New Method for Temporary Chemical Passivation

    Directory of Open Access Journals (Sweden)

    Marek Solčanský

    2012-12-01

    Full Text Available The main material parameter of silicon, that influences the effectiveness of photovoltaic cells, is the minority carrier bulk lifetime.It may change in the technological process especially during high temperature operations. Monitoring of the carrier bulk-lifetimeis necessary for modifying the whole technological process of production. For the measurement of the minority carrier bulk-lifetimethe characterization method MW PCD (Microwave Photoconductance Decay is used, where the result of measurement is the effectivecarrier lifetime, which is very dependent on the surface recombination velocity and therefore on the quality of a silicon surfacepassivation.This work deals with an examination of a different solution types for the chemical passivation of a silicon surface. Varioussolutions are tested on silicon wafers for their consequent comparison. The main purpose of this work is to find optimal solution, whichsuits the requirements of a time stability and start-up velocity of passivation, reproducibility of the measurements and a possibilityof a perfect cleaning of a passivating solution remains from a silicon surface. Another purpose of this work is to identify the parametersof other quinhydrone solutions with different concentrations as compared with the quinhydrone solution in methanol witha concentration of 0.07 mol/dm³ marked QM007 (referential solution.The method of an effective chemical passivation with a quinhydrone in methanol solution was suggested. The solution witha concentration of 0.07 mol /dm3 fulfills all required criteria. The work also confirms the influence of increased concentrationquinhydrone on the temporal stability of the passivation layer and the effect for textured silicon wafers. In conclusion, the influenceof an illumination and the temperature on the properties of the passivating solution QM007 is discussed.

  12. 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.

  13. Chemical decontamination method for radioactive metal waste

    International Nuclear Information System (INIS)

    Onuma, Tsutomu; Akimoto, Hidetoshi

    1991-01-01

    The invention relates to a decontamination method for radioactive metal waste products derived from equipment that handles radioactive materials whose surfaces have been contaminated; in particular it concerns a decontamination method that reduces the amount of radioactive waste by decontaminating radioactive waste substances to a level of radioactivity in line with normal waste products. In order to apply chemical decontamination to metal waste products whose surfaces are divided into carbon steel waste and stainless steel waste; the carbon steel waste is treated using only a primary process in which the waste is immersed in a sulfuric acid solution, while the stainless steel waste must be treated with both the primary process and then electrolytically reduces it for a specific length of time and a secondary process that uses a solution of sulfuric acid mixed with oxidizing metal salts. The method used to categorize metal waste into carbon steel waste and stainless steel waste involves determining the presence, or absence, of magnetism. Voltage is applied for a fixed duration; once that has stopped, electrolytic reduction repeats the operative cycle of applying, then stopping voltage until the potential of the radioactive metal waste is retained in the active region. 1 fig. 2 tabs

  14. Semiclassical methods in chemical reaction dynamics

    International Nuclear Information System (INIS)

    Keshavamurthy, S.

    1994-12-01

    Semiclassical approximations, simple as well as rigorous, are formulated in order to be able to describe gas phase chemical reactions in large systems. We formulate a simple but accurate semiclassical model for incorporating multidimensional tunneling in classical trajectory simulations. This model is based on the existence of locally conserved actions around the saddle point region on a multidimensional potential energy surface. Using classical perturbation theory and monitoring the imaginary action as a function of time along a classical trajectory we calculate state-specific unimolecular decay rates for a model two dimensional potential with coupling. Results are in good comparison with exact quantum results for the potential over a wide range of coupling constants. We propose a new semiclassical hybrid method to calculate state-to-state S-matrix elements for bimolecular reactive scattering. The accuracy of the Van Vleck-Gutzwiller propagator and the short time dynamics of the system make this method self-consistent and accurate. We also go beyond the stationary phase approximation by doing the resulting integrals exactly (numerically). As a result, classically forbidden probabilties are calculated with purely real time classical trajectories within this approach. Application to the one dimensional Eckart barrier demonstrates the accuracy of this approach. Successful application of the semiclassical hybrid approach to collinear reactive scattering is prevented by the phenomenon of chaotic scattering. The modified Filinov approach to evaluating the integrals is discussed, but application to collinear systems requires a more careful analysis. In three and higher dimensional scattering systems, chaotic scattering is suppressed and hence the accuracy and usefulness of the semiclassical method should be tested for such systems

  15. Semiclassical methods in chemical reaction dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Keshavamurthy, Srihari [Univ. of California, Berkeley, CA (United States)

    1994-12-01

    Semiclassical approximations, simple as well as rigorous, are formulated in order to be able to describe gas phase chemical reactions in large systems. We formulate a simple but accurate semiclassical model for incorporating multidimensional tunneling in classical trajectory simulations. This model is based on the existence of locally conserved actions around the saddle point region on a multidimensional potential energy surface. Using classical perturbation theory and monitoring the imaginary action as a function of time along a classical trajectory we calculate state-specific unimolecular decay rates for a model two dimensional potential with coupling. Results are in good comparison with exact quantum results for the potential over a wide range of coupling constants. We propose a new semiclassical hybrid method to calculate state-to-state S-matrix elements for bimolecular reactive scattering. The accuracy of the Van Vleck-Gutzwiller propagator and the short time dynamics of the system make this method self-consistent and accurate. We also go beyond the stationary phase approximation by doing the resulting integrals exactly (numerically). As a result, classically forbidden probabilties are calculated with purely real time classical trajectories within this approach. Application to the one dimensional Eckart barrier demonstrates the accuracy of this approach. Successful application of the semiclassical hybrid approach to collinear reactive scattering is prevented by the phenomenon of chaotic scattering. The modified Filinov approach to evaluating the integrals is discussed, but application to collinear systems requires a more careful analysis. In three and higher dimensional scattering systems, chaotic scattering is suppressed and hence the accuracy and usefulness of the semiclassical method should be tested for such systems.

  16. Method for fractional solid-waste sampling and chemical analysis

    DEFF Research Database (Denmark)

    Riber, Christian; Rodushkin, I.; Spliid, Henrik

    2007-01-01

    four subsampling methods and five digestion methods, paying attention to the heterogeneity and the material characteristics of the waste fractions, it was possible to determine 61 substances with low detection limits, reasonable variance, and high accuracy. For most of the substances of environmental...... of variance (20-85% of the overall variation). Only by increasing the sample size significantly can this variance be reduced. The accuracy and short-term reproducibility of the chemical characterization were good, as determined by the analysis of several relevant certified reference materials. Typically, six...... to eight different certified reference materials representing a range of concentrations levels and matrix characteristics were included. Based on the documentation provided, the methods introduced were considered satisfactory for characterization of the chemical composition of waste-material fractions...

  17. Investigating hydrogel dosimeter decomposition by chemical methods

    International Nuclear Information System (INIS)

    Jordan, Kevin

    2015-01-01

    The chemical oxidative decomposition of leucocrystal violet micelle hydrogel dosimeters was investigated using the reaction of ferrous ions with hydrogen peroxide or sodium bicarbonate with hydrogen peroxide. The second reaction is more effective at dye decomposition in gelatin hydrogels. Additional chemical analysis is required to determine the decomposition products

  18. The role of chemical engineering in medicinal research including Alzheimer’s

    DEFF Research Database (Denmark)

    Kontogeorgis, Georgios M.

    2015-01-01

    Various disciplines of chemical engineering, especially thermodynamics and kinetics, play an important role in medicinal research and this has been particularly recognized during the last 10–15 years (von Stockar and van der Wielen, J Biotechnol 59:25, 1997; Prausnitz, Fluid Phase Equilib 53......:439, 1989; Prausnitz, Pure Appl Chem 79:1435, 2007; Dey and Prausnitz, Ind Eng Chem Res 50:3, 2011; Prausnitz, J Chem Thermodynamics 35:21, 2003; Tsivintzelis et al. AIChE J 55:756, 2009). It is expected that during the twenty-first century chemical engineering and especially thermodynamics can contribute......” disease), and Alzheimer’s which are connected to “protein aggregation.” Several articles in the Perspectives section of prominent chemical engineering journals have addressed this issue (Hall, AIChE J 54:1956, 2008; Vekilov, AIChE J 54:2508, 2008). This work reviews recent applications of thermodynamics...

  19. Minimizing the Free Energy: A Computer Method for Teaching Chemical Equilibrium Concepts.

    Science.gov (United States)

    Heald, Emerson F.

    1978-01-01

    Presents a computer method for teaching chemical equilibrium concepts using material balance conditions and the minimization of the free energy. Method for the calculation of chemical equilibrium, the computer program used to solve equilibrium problems and applications of the method are also included. (HM)

  20. Device and method for enhanced collection and assay of chemicals with high surface area ceramic

    Science.gov (United States)

    Addleman, Raymond S.; Li, Xiaohong Shari; Chouyyok, Wilaiwan; Cinson, Anthony D.; Bays, John T.; Wallace, Krys

    2016-02-16

    A method and device for enhanced capture of target analytes is disclosed. This invention relates to collection of chemicals for separations and analysis. More specifically, this invention relates to a solid phase microextraction (SPME) device having better capability for chemical collection and analysis. This includes better physical stability, capacity for chemical collection, flexible surface chemistry and high affinity for target analyte.

  1. Assessment of chemical exposures: calculation methods for environmental professionals

    National Research Council Canada - National Science Library

    Daugherty, Jack E

    1997-01-01

    ... on by scientists, businessmen, and policymakers. Assessment of Chemical Exposures: Calculation Methods for Environmental Professionals addresses the expanding scope of exposure assessments in both the workplace and environment...

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

    Science.gov (United States)

    Armour, M. A.; And Others

    1985-01-01

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

  3. 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.

  4. Chemical Method of Urine Volume Measurement

    Science.gov (United States)

    Petrack, P.

    1967-01-01

    A system has been developed and qualified as flight hardware for the measurement of micturition volumes voided by crewmen during Gemini missions. This Chemical Urine Volume Measurement System (CUVMS) is used for obtaining samples of each micturition for post-flight volume determination and laboratory analysis for chemical constituents of physiological interest. The system is versatile with respect to volumes measured, with a capacity beyond the largest micturition expected to be encountered, and with respect to mission duration of inherently indefinite length. The urine sample is used for the measurement of total micturition volume by a tracer dilution technique, in which a fixed, predetermined amount of tritiated water is introduced and mixed into the voided urine, and the resulting concentration of the tracer in the sample is determined with a liquid scintillation spectrometer. The tracer employed does not interfere with the analysis for the chemical constituents of the urine. The CUVMS hardware consists of a four-way selector valve in which an automatically operated tracer metering pump is incorporated, a collection/mixing bag, and tracer storage accumulators. The assembled system interfaces with a urine receiver at the selector valve inlet, sample bags which connect to the side of the selector valve, and a flexible hose which carries the excess urine to the overboard drain connection. Results of testing have demonstrated system volume measurement accuracy within the specification limits of +/-5%, and operating reliability suitable for system use aboard the GT-7 mission, in which it was first used.

  5. Variational methods for chemical and nuclear reactions

    International Nuclear Information System (INIS)

    Crawford, O.H.

    1977-01-01

    All the variational functionals are derived which satisfy certain criteria of suitability for molecular and nuclear scattering, below the threshold energy for three-body breakup. The existence and uniqueness of solutions are proven. The most general suitable functional is specialized, by particular values of its parameters, to Kohn's taneta, Kato's cot(eta-theta), the inverse Kohn coeta, Kohn's S matrix, our S matrix, Lane and Robson's functional, and several new functionals, an infinite number of which are contained in the general expression. Four general ways of deriving algebraic methods from a given functional are discussed, and illustrated with specific algebraic results. These include equations of Lane and Robson and of Kohn, the fundamental R matrix relation, and new equations. The relative configuration space is divided as in the Wigner R matrix theory, and trial wavefunctions are needed for only the region where all the particles are interacting. In addition, a version of the general functional is presented which does not require any division of space

  6. Quality Control Guidelines for SAM Chemical Methods

    Science.gov (United States)

    Learn more about quality control guidelines and recommendations for the analysis of samples using the chemistry methods listed in EPA's Selected Analytical Methods for Environmental Remediation and Recovery (SAM).

  7. Field theoretical methods in chemical physics

    International Nuclear Information System (INIS)

    Paul, R.

    1982-01-01

    Field theory will become an important tool for the chemist, and this book presents a clear and thorough account of the theory itself and its applications for solving a wide variety of chemical problems. The author has brought together the foundations upon which the many and varied applications of field theory have been built, giving more intermediate steps than is usual in the derivations. This makes the book easily accessible to anyone with a background of calculus, statistical thermodynamics and elementary quantum chemistry. (orig./HK)

  8. 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.)

  9. Methods for the Determination of Chemical Contaminants in Drinking Water. Training Manual.

    Science.gov (United States)

    Office of Water Program Operations (EPA), Cincinnati, OH. National Training and Operational Technology Center.

    This training manual, intended for chemists and technicians with little or no experience in chemical procedures required to monitor drinking water, covers analytical methods for inorganic and organic chemical contaminants listed in the interim primary drinking water regulations. Topics include methods for heavy metals, nitrate, and organic…

  10. Method of operating a thermal engine powered by a chemical reaction

    Science.gov (United States)

    Ross, J.; Escher, C.

    1988-06-07

    The invention involves a novel method of increasing the efficiency of a thermal engine. Heat is generated by a non-linear chemical reaction of reactants, said heat being transferred to a thermal engine such as Rankine cycle power plant. The novel method includes externally perturbing one or more of the thermodynamic variables of said non-linear chemical reaction. 7 figs.

  11. A class of chemical pinning centers including two elements foreign to HTS

    Energy Technology Data Exchange (ETDEWEB)

    Weinstein, Roy; Sawh, Ravi-Persad

    2003-01-01

    Very small deposits are formed when two foreign elements, A and B, are added to textured (RE)BCO. These deposits increase the J{sub c} of samples and hence the maximum trapped field. Deposit sizes are generally in the range 200-400 nm. Their chemical composition is (A{sub x},B{sub y})(RE)Ba{sub 2}O{sub 6}, where x+y=1 and x=y{+-}0.1. Their structure is double perovskite. The deposits produce two types of pinning, one by refinement (e.g., of the Y211 phase) and the other due to the double perovskite deposits themselves. In those cases tested, the refinement increases J{sub c} by factors exceeding 1.33, and the deposits increase J{sub c} by factors exceeding 2, for a total increase by a factor exceeding 2.66. Element A can be U, W or Mo. Element B can be Pt or Zr. We speculate on possible additional elements in classes A and B.

  12. Chemical decontamination method for radioactive metal waste

    International Nuclear Information System (INIS)

    Onuma, Tsutomu; Tanaka, Akio; Shibuya, Sadao.

    1991-01-01

    When contaminants mainly composed of copper remained on the surface of stainless steel wastes sent from an electrolytic reduction as a first step are chemically decontaminated, metal wastes are discriminated to carbon steel wastes and stainless steel wastes. Then, the carbon steel wastes are applied only with the first step of immersing in a sulfuric acid solution, and stainless steel wastes are applied with a first step of immersing into a sulfuric acid solution for electrolytic reduction for a predetermined period of time and a second step of immersing into a liquid in which an oxidative metal salt is added to sulfuric acid. The decontamination liquid which is used for immersing the stainless steel wastes in the second step and the oxidation force of which is lowered is used as the sulfuric acid solution in the first step for the carbon steel wastes. In view of the above, the decontamination liquid of the second step can be utilized most effectively, enabling to greatly decrease the secondary wastes and to improve decontamination efficiency. (T.M.)

  13. Test Methods for Evaluating Solid Waste, Physical/Chemical Methods. First Update. (3rd edition)

    International Nuclear Information System (INIS)

    Friedman; Sellers.

    1988-01-01

    The proposed Update is for Test Methods for Evaluating Solid Waste, Physical/Chemical Methods, SW-846, Third Edition. Attached to the report is a list of methods included in the proposed update indicating whether the method is a new method, a partially revised method, or a totally revised method. Do not discard or replace any of the current pages in the SW-846 manual until the proposed update I package is promulgated. Until promulgation of the update package, the methods in the update package are not officially part of the SW-846 manual and thus do not carry the status of EPA-approved methods. In addition to the proposed Update, six finalized methods are included for immediate inclusion into the Third Edition of SW-846. Four methods, originally proposed October 1, 1984, will be finalized in a soon to be released rulemaking. They are, however, being submitted to subscribers for the first time in the update. These methods are 7211, 7381, 7461, and 7951. Two other methods were finalized in the 2nd Edition of SW-846. They were inadvertantly omitted from the 3rd Edition and are not being proposed as new. These methods are 7081 and 7761

  14. Chemical aspects of nuclear methods of analysis

    International Nuclear Information System (INIS)

    1985-01-01

    This final report includes papers which fall into three general areas: development of practical pre-analysis separation techniques, uranium/thorium separation from other elements for analytical and processing operations, and theory and mechanism of separation techniques. A separate abstract was prepared for each of the 9 papers

  15. Investigation of Evaluation method of chemical runaway reaction

    International Nuclear Information System (INIS)

    Sato, Yoshihiko; Sasaya, Shinji; Kurakata, Koichiro; Nojiri, Ichiro

    2002-02-01

    Safety study 'Study of evaluation of abnormal occurrence for chemical substances in the nuclear fuel facilities' will be carried out from 2001 to 2005. In this study, the prediction of thermal hazards of chemical substances will be investigated and prepared. The hazard prediction method of chemical substances will be constructed from these results. Therefore, the hazard prediction methods applied in the chemical engineering in which the chemical substances with the hazard of fire and explosion were often treated were investigated. CHETAH (The ASTM Computer Program for Chemical Thermodynamic and Energy Release Evaluation) developed by ASTM (American Society for Testing and Materials) and TSS (Thermal Safety Software) developed by CISP (ChemInform St. Petersburg) were introduced and the fire and explosion hazards of chemical substances and reactions in the reprocessing process were evaluated. From these evaluated results, CHETAH could almost estimate the heat of reaction at 10% accuracy. It was supposed that CHETAH was useful as a screening for the hazards of fire and explosion of the new chemical substances and so on. TSS could calculate the reaction rate and the reaction behavior from the data measured by the various calorimeters rapidly. It was supposed that TSS was useful as an evaluation method for the hazards of fire and explosion of the new chemical reactions and so on. (author)

  16. Composite materials and bodies including silicon carbide and titanium diboride and methods of forming same

    Science.gov (United States)

    Lillo, Thomas M.; Chu, Henry S.; Harrison, William M.; Bailey, Derek

    2013-01-22

    Methods of forming composite materials include coating particles of titanium dioxide with a substance including boron (e.g., boron carbide) and a substance including carbon, and reacting the titanium dioxide with the substance including boron and the substance including carbon to form titanium diboride. The methods may be used to form ceramic composite bodies and materials, such as, for example, a ceramic composite body or material including silicon carbide and titanium diboride. Such bodies and materials may be used as armor bodies and armor materials. Such methods may include forming a green body and sintering the green body to a desirable final density. Green bodies formed in accordance with such methods may include particles comprising titanium dioxide and a coating at least partially covering exterior surfaces thereof, the coating comprising a substance including boron (e.g., boron carbide) and a substance including carbon.

  17. Alternative Chemical Amplification Methods for Peroxy Radical Detection

    Science.gov (United States)

    Wood, E. C. D.

    2014-12-01

    Peroxy radicals (HO2, CH3O2, etc.) are commonly detected by the chemical amplification technique, in which ambient air is mixed with high concentrations of CO and NO, initiating a chain reaction that produces 30 - 200 NO2 molecules per sampled peroxy radical. The NO2 is then measured by one of several techniques. With the exception of CIMS-based techniques, the chemical amplification method has undergone only incremental improvements since it was first introduced in 1982. The disadvantages of the technique include the need to use high concentrations of CO and the greatly reduced sensitivity of the amplification chain length in the presence of water vapor. We present a new chemical amplification scheme in which either ethane or acetaldehyde is used in place of CO, with the NO2 product detected using Cavity Attenuated Phase Shift spectroscopy (CAPS). Under dry conditions, the amplification factor of the alternative amplifiers are approximately six times lower than the CO-based amplifier. The relative humidity "penalty" is not as severe, however, such that at typical ambient relative humidity (RH) values the amplification factor is within a factor of three of the CO-based amplifier. Combined with the NO2 sensitivity of CAPS and a dual-channel design, the detection limit of the ethane amplifier is less than 2 ppt (1 minute average, signal-to-noise ratio 2). The advantages of these alternative chemical amplification schemes are improved safety, a reduced RH correction, and increased sensitivity to organic peroxy radicals relative to HO2.

  18. Chemical Compounds and Extraction Methods of ?Maollahm?

    OpenAIRE

    Sadeghpoor, Omid; Dayeni, Manijeh; Razi, Samane

    2016-01-01

    Background: Maollahm or meat juice, a by-product of meat, is a traditional remedy in Persian medicine. This product was used as a nourishment or treatment substance for sick people. According to the ancient Persian medicine, animal meat has more affinity with the human body and the body easily absorbs its nutrition. Therefore, one could resort to maollahm for patients requiring urgent nourishment to boost and strengthen their body. Methods: In this work, different ways of preparing maollahm f...

  19. Investigation of Chemical Equilibrium Kinetics by the Electromigration Method

    CERN Document Server

    Bozhikov, G A; Bontchev, G D; Maslov, O D; Milanov, M V; Dmitriev, S N

    2002-01-01

    Measurement of the chemical reaction rates for complex formation as well as hydrolysis type reactions by the method of horizontal zone electrophoresis is outlined. The correlation between chemical equilibrium kinetics and electrodiffusion processes in a constant d.c. electric field is described. In model electromigration experiments the reaction rate constant of the complex formation of Hf(IV) and DTPA is determined.

  20. Particle-based modeling of heterogeneous chemical kinetics including mass transfer

    Science.gov (United States)

    Sengar, A.; Kuipers, J. A. M.; van Santen, Rutger A.; Padding, J. T.

    2017-08-01

    Connecting the macroscopic world of continuous fields to the microscopic world of discrete molecular events is important for understanding several phenomena occurring at physical boundaries of systems. An important example is heterogeneous catalysis, where reactions take place at active surfaces, but the effective reaction rates are determined by transport limitations in the bulk fluid and reaction limitations on the catalyst surface. In this work we study the macro-micro connection in a model heterogeneous catalytic reactor by means of stochastic rotation dynamics. The model is able to resolve the convective and diffusive interplay between participating species, while including adsorption, desorption, and reaction processes on the catalytic surface. Here we apply the simulation methodology to a simple straight microchannel with a catalytic strip. Dimensionless Damkohler numbers are used to comment on the spatial concentration profiles of reactants and products near the catalyst strip and in the bulk. We end the discussion with an outlook on more complicated geometries and increasingly complex reactions.

  1. Particle-based modeling of heterogeneous chemical kinetics including mass transfer.

    Science.gov (United States)

    Sengar, A; Kuipers, J A M; van Santen, Rutger A; Padding, J T

    2017-08-01

    Connecting the macroscopic world of continuous fields to the microscopic world of discrete molecular events is important for understanding several phenomena occurring at physical boundaries of systems. An important example is heterogeneous catalysis, where reactions take place at active surfaces, but the effective reaction rates are determined by transport limitations in the bulk fluid and reaction limitations on the catalyst surface. In this work we study the macro-micro connection in a model heterogeneous catalytic reactor by means of stochastic rotation dynamics. The model is able to resolve the convective and diffusive interplay between participating species, while including adsorption, desorption, and reaction processes on the catalytic surface. Here we apply the simulation methodology to a simple straight microchannel with a catalytic strip. Dimensionless Damkohler numbers are used to comment on the spatial concentration profiles of reactants and products near the catalyst strip and in the bulk. We end the discussion with an outlook on more complicated geometries and increasingly complex reactions.

  2. Method of cleaning oil slicks and chemical spills

    International Nuclear Information System (INIS)

    Billings, L.

    1992-01-01

    This patent describes a method of cleaning a floating chemical spill on a body of water. It comprises: providing a quantity of popular bark-based pelleted or granular product, flotation means and a flexible net having openings generally smaller than the smallest whole pellet dimension of the pelleted product, spreading the net over a chemical spill on the body of water, connecting the floatation means to the net thereby supporting the net adjacent the surface of the body of water, placing the poplar bark-based product on the net, absorbing the floating chemical spill into the product, and removing the chemical soaked product from the body of water

  3. Chemical residues in Dolphins from the US Atlantic coast including atlantic bottlenose obtained during the 1987/88 mass mortality

    Energy Technology Data Exchange (ETDEWEB)

    Kuehl, D.W.; Haebler, R.; Potter, C.

    1991-01-01

    Bottlenose dolphins (Tursiops truncatus) collected during the 1987/88 mass mortality event along the Atlantic coast of the United States have been analyzed for anthropogenic chemical contaminants. Average contaminant concentrations in adult males were higher than the average concentrations measured in adult females. Females could be divided into two groups by contaminant concentrations, one with low concentrations, and another with concentrations 4.4 times (PCBs) to 8.9 times (p,p'-DDE) greater. Contaminant concentrations in bottlenose were generally greater than the concentrations measured in either common (Delphinus delphis) or white-sided (Lagernorhynchus acutus) dolphins from the western North Atlantic Ocean. A subset of animals screened for unusual chemical contaminants showed that numerous polybrominated chemicals were present, including polybrominated biphenyls and diphenyl ethers not previously found in marine mammals from U.S. coastal waters.

  4. Solar cells, structures including organometallic halide perovskite monocrystalline films, and methods of preparation thereof

    KAUST Repository

    Bakr, Osman; Peng, Wei; Wang, Lingfei

    2017-01-01

    Embodiments of the present disclosure provide for solar cells including an organometallic halide perovskite monocrystalline film (see fig. 1.1B), other devices including the organometallic halide perovskite monocrystalline film, methods of making

  5. 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.

  6. Odour detection methods: olfactometry and chemical sensors.

    Science.gov (United States)

    Brattoli, Magda; de Gennaro, Gianluigi; de Pinto, Valentina; Loiotile, Annamaria Demarinis; Lovascio, Sara; Penza, Michele

    2011-01-01

    The complexity of the odours issue arises from the sensory nature of smell. From the evolutionary point of view olfaction is one of the oldest senses, allowing for seeking food, recognizing danger or communication: human olfaction is a protective sense as it allows the detection of potential illnesses or infections by taking into account the odour pleasantness/unpleasantness. Odours are mixtures of light and small molecules that, coming in contact with various human sensory systems, also at very low concentrations in the inhaled air, are able to stimulate an anatomical response: the experienced perception is the odour. Odour assessment is a key point in some industrial production processes (i.e., food, beverages, etc.) and it is acquiring steady importance in unusual technological fields (i.e., indoor air quality); this issue mainly concerns the environmental impact of various industrial activities (i.e., tanneries, refineries, slaughterhouses, distilleries, civil and industrial wastewater treatment plants, landfills and composting plants) as sources of olfactory nuisances, the top air pollution complaint. Although the human olfactory system is still regarded as the most important and effective "analytical instrument" for odour evaluation, the demand for more objective analytical methods, along with the discovery of materials with chemo-electronic properties, has boosted the development of sensor-based machine olfaction potentially imitating the biological system. This review examines the state of the art of both human and instrumental sensing currently used for the detection of odours. The olfactometric techniques employing a panel of trained experts are discussed and the strong and weak points of odour assessment through human detection are highlighted. The main features and the working principles of modern electronic noses (E-Noses) are then described, focusing on their better performances for environmental analysis. Odour emission monitoring carried out through

  7. Odour Detection Methods: Olfactometry and Chemical Sensors

    Directory of Open Access Journals (Sweden)

    Sara Lovascio

    2011-05-01

    Full Text Available The complexity of the odours issue arises from the sensory nature of smell. From the evolutionary point of view olfaction is one of the oldest senses, allowing for seeking food, recognizing danger or communication: human olfaction is a protective sense as it allows the detection of potential illnesses or infections by taking into account the odour pleasantness/unpleasantness. Odours are mixtures of light and small molecules that, coming in contact with various human sensory systems, also at very low concentrations in the inhaled air, are able to stimulate an anatomical response: the experienced perception is the odour. Odour assessment is a key point in some industrial production processes (i.e., food, beverages, etc. and it is acquiring steady importance in unusual technological fields (i.e., indoor air quality; this issue mainly concerns the environmental impact of various industrial activities (i.e., tanneries, refineries, slaughterhouses, distilleries, civil and industrial wastewater treatment plants, landfills and composting plants as sources of olfactory nuisances, the top air pollution complaint. Although the human olfactory system is still regarded as the most important and effective “analytical instrument” for odour evaluation, the demand for more objective analytical methods, along with the discovery of materials with chemo-electronic properties, has boosted the development of sensor-based machine olfaction potentially imitating the biological system. This review examines the state of the art of both human and instrumental sensing currently used for the detection of odours. The olfactometric techniques employing a panel of trained experts are discussed and the strong and weak points of odour assessment through human detection are highlighted. The main features and the working principles of modern electronic noses (E-Noses are then described, focusing on their better performances for environmental analysis. Odour emission monitoring

  8. Safety in the Chemical Laboratory--Chemical Management: A Method for Waste Reduction.

    Science.gov (United States)

    Pine, Stanley H.

    1984-01-01

    Discusses methods for reducing or eliminating waste disposal problems in the chemistry laboratory, considering both economic and environmental aspects of the problems. Proposes inventory control, shared use, solvent recycling, zero effluent, and various means of disposing of chemicals. (JM)

  9. Calculation of Multiphase Chemical Equilibrium by the Modified RAND Method

    DEFF Research Database (Denmark)

    Tsanas, Christos; Stenby, Erling Halfdan; Yan, Wei

    2017-01-01

    method. The modified RAND extends the classical RAND method from single-phase chemical reaction equilibrium of ideal systems to multiphase chemical equilibrium of nonideal systems. All components in all phases are treated in the same manner and the system Gibbs energy can be used to monitor convergence....... This is the first time that modified RAND was applied to multiphase chemical equilibrium systems. The combined algorithm was tested using nine examples covering vapor–liquid (VLE) and vapor–liquid–liquid equilibria (VLLE) of ideal and nonideal reaction systems. Successive substitution provided good initial......A robust and efficient algorithm for simultaneous chemical and phase equilibrium calculations is proposed. It combines two individual nonstoichiometric solving procedures: a nested-loop method with successive substitution for the first steps and final convergence with the second-order modified RAND...

  10. Virtual screening methods as tools for drug lead discovery from large chemical libraries.

    Science.gov (United States)

    Ma, X H; Zhu, F; Liu, X; Shi, Z; Zhang, J X; Yang, S Y; Wei, Y Q; Chen, Y Z

    2012-01-01

    Virtual screening methods have been developed and explored as useful tools for searching drug lead compounds from chemical libraries, including large libraries that have become publically available. In this review, we discussed the new developments in exploring virtual screening methods for enhanced performance in searching large chemical libraries, their applications in screening libraries of ~ 1 million or more compounds in the last five years, the difficulties in their applications, and the strategies for further improving these methods.

  11. Method of waste stabilization with dewatered chemically bonded phosphate ceramics

    Science.gov (United States)

    Wagh, Arun; Maloney, Martin D.

    2010-06-29

    A method of stabilizing a waste in a chemically bonded phosphate ceramic (CBPC). The method consists of preparing a slurry including the waste, water, an oxide binder, and a phosphate binder. The slurry is then allowed to cure to a solid, hydrated CBPC matrix. Next, bound water within the solid, hydrated CBPC matrix is removed. Typically, the bound water is removed by applying heat to the cured CBPC matrix. Preferably, the quantity of heat applied to the cured CBPC matrix is sufficient to drive off water bound within the hydrated CBPC matrix, but not to volatalize other non-water components of the matrix, such as metals and radioactive components. Typically, a temperature range of between 100.degree. C.-200.degree. C. will be sufficient. In another embodiment of the invention wherein the waste and water have been mixed prior to the preparation of the slurry, a select amount of water may be evaporated from the waste and water mixture prior to preparation of the slurry. Another aspect of the invention is a direct anyhydrous CBPC fabrication method wherein water is removed from the slurry by heating and mixing the slurry while allowing the slurry to cure. Additional aspects of the invention are ceramic matrix waste forms prepared by the methods disclosed above.

  12. Chemical analysis of cyanide in cyanidation process: review of methods

    International Nuclear Information System (INIS)

    Nova-Alonso, F.; Elorza-Rodriguez, E.; Uribe-Salas, A.; Perez-Garibay, R.

    2007-01-01

    Cyanidation, the world wide method for precious metals recovery, the chemical analysis of cyanide, is a very important, but complex operation. Cyanide can be present forming different species, each of them with different stability, toxicity, analysis method and elimination technique. For cyanide analysis, there exists a wide selection of analytical methods but most of them present difficulties because of the interference of species present in the solution. This paper presents the different available methods for chemical analysis of cyanide: titration, specific electrode and distillation, giving special emphasis on the interferences problem, with the aim of helping in the interpretation of the results. (Author)

  13. Comparison of different methods to include recycling in LCAs of aluminium cans and disposable polystyrene cups

    NARCIS (Netherlands)

    Harst-Wintraecken, van der Eugenie; Potting, José; Kroeze, Carolien

    2016-01-01

    Many methods have been reported and used to include recycling in life cycle assessments (LCAs). This paper evaluates six widely used methods: three substitution methods (i.e. substitution based on equal quality, a correction factor, and alternative material), allocation based on the number of

  14. Effect of drying methods on the chemical composition of three ...

    African Journals Online (AJOL)

    Three methods of drying (oven, sun and smoke) were used to dry Bonga spp., Sardinella spp. and Heterotis niloticus. The physico-chemical and minerals contents of the sample were determined using standard methods. Oven dried H. niloticus recorded the highest (16.42%) moisture content while the least moisture content ...

  15. A identification system for chemical warfare agents with PGNAA method

    International Nuclear Information System (INIS)

    Wang Bairong; Yin Guanghua; Yang Zhongping

    2006-01-01

    The principle and the experimental commanding of Chemical warfare Agents Identification with PGNAA method are discussed in this paper. The choosing of Detector, neutron source and the data processing method are detailed. Finally, a set of experimental instruments composed of Cf-232 and BGO detector is developed based on the theory discussed above. (authors)

  16. Identification system for chemical warfare agents with PGNAA method

    International Nuclear Information System (INIS)

    Wang Bairong; Yin Guanghua; Yang Zhongpin

    2007-01-01

    The principle and the experimental commanding of Chemical warfare Agents Identification with PGNAA method are discussed in this paper. The choosing of detector, neutron source and the data processing method are detailed. Finally, a set of experimental instruments composed of Cf-232 and BGO detector is developed based on this theory discussed above. (authors)

  17. Methods of uranium isotpic separation by chemical exchange chromatography

    International Nuclear Information System (INIS)

    Pena V, L.A.; Valle M, L.

    1985-01-01

    Chemical exchange chromatography as applied to isotope separation has undergone a constant development during the last few years. The results so far indicate that this method could eventually become commercially useful. This work presents a critical review of the experimental methods presently under study by principal research groups, and which have not get been compared. (Author)

  18. Insights: A New Method to Balance Chemical Equations.

    Science.gov (United States)

    Garcia, Arcesio

    1987-01-01

    Describes a method designed to balance oxidation-reduction chemical equations. Outlines a method which is based on changes in the oxidation number that can be applied to both molecular reactions and ionic reactions. Provides examples and delineates the steps to follow for each type of equation balancing. (TW)

  19. New methods of sup(111)In chemical separation

    International Nuclear Information System (INIS)

    Santos, D.F.; Osso Junior, J.A.; Bastos, M.A.V.; Britto, J.L.Q.; Silva, R.F.

    1986-01-01

    The cation exchange and thermochromatography methods for chemical separation of sup(111) In from silver targets are described. The cation exchange method is based on the difference between In and Ag distribution coefficients on cation exchange resin treated with HNO sub(3). The thermochromatography consists of indium diffusion on silver melted after sublimation and posterior condensation. (M.C.K.)

  20. Systems and Methods for Fabricating Structures Including Metallic Glass-Based Materials Using Low Pressure Casting

    Science.gov (United States)

    Hofmann, Douglas C. (Inventor); Kennett, Andrew (Inventor)

    2018-01-01

    Systems and methods to fabricate objects including metallic glass-based materials using low-pressure casting techniques are described. In one embodiment, a method of fabricating an object that includes a metallic glass-based material includes: introducing molten alloy into a mold cavity defined by a mold using a low enough pressure such that the molten alloy does not conform to features of the mold cavity that are smaller than 100 microns; and cooling the molten alloy such that it solidifies, the solid including a metallic glass-based material.

  1. Plant management in natural areas: balancing chemical, mechanical, and cultural control methods

    Science.gov (United States)

    Steven Manning; James. Miller

    2011-01-01

    After determining the best course of action for control of an invasive plant population, it is important to understand the variety of methods available to the integrated pest management professional. A variety of methods are now widely used in managing invasive plants in natural areas, including chemical, mechanical, and cultural control methods. Once the preferred...

  2. A method for the computation of turbulent polymeric liquids including hydrodynamic interactions and chain entanglements

    Energy Technology Data Exchange (ETDEWEB)

    Kivotides, Demosthenes, E-mail: demosthenes.kivotides@strath.ac.uk

    2017-02-12

    An asymptotically exact method for the direct computation of turbulent polymeric liquids that includes (a) fully resolved, creeping microflow fields due to hydrodynamic interactions between chains, (b) exact account of (subfilter) residual stresses, (c) polymer Brownian motion, and (d) direct calculation of chain entanglements, is formulated. Although developed in the context of polymeric fluids, the method is equally applicable to turbulent colloidal dispersions and aerosols. - Highlights: • An asymptotically exact method for the computation of polymer and colloidal fluids is developed. • The method is valid for all flow inertia and all polymer volume fractions. • The method models entanglements and hydrodynamic interactions between polymer chains.

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

    International Nuclear Information System (INIS)

    Teuschler, Linda K.

    2007-01-01

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

  4. [Bioinorganic chemical composition of the lens and methods of its investigation].

    Science.gov (United States)

    Avetisov, S E; Novikov, I A; Pakhomova, N A; Motalov, V G

    2018-01-01

    Bioinorganic chemical composition of the lens of human and experimental animals (cows, dogs, rats, rabbits) have been analyzed in various studies. In most cases, the studies employed different methods to determine the gross (total) composition of chemical elements and their concentrations in the examined samples. Less frequently, they included an assessment of the distribution of chemical elements in the lens and correlation of their concentration with its morphological changes. Chemical elements from all groups (series) of the periodic classification system were discovered in the lens substance. Despite similar investigation methods, different authors obtained contradicting results on the chemical composition of the lens. This article presents data suggesting possible correlation between inorganic chemical elements in the lens substance with the development and formation of lenticular opacities. All currently employed methods are known to only analyze limited number of select chemical elements in the tissues and do not consider the whole range of elements that can be analyzed with existing technology; furthermore, the majority of studies are conducted on the animal model lens. Therefore, it is feasible to continue the development of the chemical microanalysis method by increasing the sensitivity of Scanning Electron Microscopy with Energy Dispersive Spectroscopy (SEM/EDS) with the purpose of assessing the gross chemical composition and distribution of the elements in the lens substance, as well as revealing possible correlation between element concentration and morphological changes in the lens.

  5. Development of calculation method for one-dimensional kinetic analysis in fission reactors, including feedback effects

    International Nuclear Information System (INIS)

    Paixao, S.B.; Marzo, M.A.S.; Alvim, A.C.M.

    1986-01-01

    The calculation method used in WIGLE code is studied. Because of the non availability of such a praiseworthy solution, expounding the method minutely has been tried. This developed method has been applied for the solution of the one-dimensional, two-group, diffusion equations in slab, axial analysis, including non-boiling heat transfer, accountig for feedback. A steady-state program (CITER-1D), written in FORTRAN 4, has been implemented, providing excellent results, ratifying the developed work quality. (Author) [pt

  6. Solar cells, structures including organometallic halide perovskite monocrystalline films, and methods of preparation thereof

    KAUST Repository

    Bakr, Osman M.

    2017-03-02

    Embodiments of the present disclosure provide for solar cells including an organometallic halide perovskite monocrystalline film (see fig. 1.1B), other devices including the organometallic halide perovskite monocrystalline film, methods of making organometallic halide perovskite monocrystalline film, and the like.

  7. Methods for conversion of carbohydrates in ionic liquids to value-added chemicals

    Science.gov (United States)

    Zhao, Haibo [The Woodlands, TX; Holladay, Johnathan E [Kennewick, WA; Zhang, Zongchao C [Norwood, NJ

    2011-05-10

    Methods are described for converting carbohydrates including, e.g., monosaccharides, disaccharides, and polysaccharides in ionic liquids to value-added chemicals including furans, useful as chemical intermediates and/or feedstocks. Fructose is converted to 5-hydroxylmethylfurfural (HMF) in the presence of metal halide and acid catalysts. Glucose is effectively converted to HMF in the presence of chromium chloride catalysts. Yields of up to about 70% are achieved with low levels of impurities such as levulinic acid.

  8. In vitro antibacterial and chemical properties of essential oils including native plants from Brazil against pathogenic and resistant bacteria.

    Science.gov (United States)

    Barbosa, Lidiane Nunes; Probst, Isabella da Silva; Andrade, Bruna Fernanda Murbach Teles; Alves, Fernanda Cristina Bérgamo; Albano, Mariana; da Cunha, Maria de Lourdes Ribeiro de Souza; Doyama, Julio Toshimi; Rall, Vera Lúcia Mores; Fernandes Júnior, Ary

    2015-01-01

    The antimicrobials products from plants have increased in importance due to the therapeutic potential in the treatment of infectious diseases. Therefore, we aimed to examine the chemical characterisation (GC-MS) of essential oils (EO) from seven plants and measure antibacterial activities against bacterial strains isolated from clinical human specimens (methicillin-resistant Staphylococcus aureus (MRSA) and sensitive (MSSA), Escherichia coli, Pseudomonas aeruginosa, Salmonella Typhimurium) and foods (Salmonella Enteritidis). Assays were performed using the minimal inhibitory concentration (MIC and MIC90%) (mg/mL) by agar dilution and time kill curve methods (log CFU/mL) to aiming synergism between EO. EO chemical analysis showed a predominance of terpenes and its derivatives. The highest antibacterial activities were with Cinnamomun zeylanicum (0.25 mg/mL on almost bacteria tested) and Caryophyllus aromaticus EO (2.40 mg/mL on Salmonella Enteritidis), and the lowest activity was with Eugenia uniflora (from 50.80 mg/mL against MSSA to 92.40 mg/mL against both Salmonella sources and P. aeruginosa) EO. The time kill curve assays revealed the occurrence of bactericide synergism in combinations of C. aromaticus and C. zeylanicum with Rosmarinus. officinalis. Thus, the antibacterial activities of the EO were large and this can also be explained by complex chemical composition of the oils tested in this study and the synergistic effect of these EO, yet requires further investigation because these interactions between the various chemical compounds can increase or reduce (antagonism effect) the inhibitory effect of essential oils against bacterial strains.

  9. Method of manipulating the chemical properties of water to improve the effectiveness of a desired chemical process

    Science.gov (United States)

    Hawthorne, Steven B.; Miller, David J.; Yang, Yu; Lagadec, Arnaud Jean-Marie

    1999-01-01

    The method of the present invention is adapted to manipulate the chemical properties of water in order to improve the effectiveness of a desired chemical process. The method involves heating the water in the vessel to subcritical temperatures between 100.degree. to 374.degree. C. while maintaining sufficient pressure to the water to maintain the water in the liquid state. Various physiochemical properties of the water can be manipulated including polarity, solute solubility, surface tension, viscosity, and the disassociation constant. The method of the present invention has various uses including extracting organics from solids and semisolids such as soil, selectively extracting desired organics from nonaqueous liquids, selectively separating organics using sorbent phases, enhancing reactions by controlling the disassociation constant of water, cleaning waste water, and removing organics from water using activated carbon or other suitable sorbents.

  10. APPLICATION OF CHEMICAL METHODS TO THE SOLID WASTE MANAGEMENT

    Directory of Open Access Journals (Sweden)

    C. P. Bulimaga

    2008-12-01

    Full Text Available The present article is a synthesis analysis of application of chemical methods for the development of technologies of hazardous waste management. Here are offered some technologies of neutralization of the waste containing hexacyanofferates, galvanic wastes and those with contain of vanadium, which are collected at Power Thermoelectric Plants.

  11. Comparison of traditional physico-chemical methods and molecular ...

    African Journals Online (AJOL)

    This study was aim to review the efficiency of molecular markers and traditional physico-chemical methods for the identification of basmati rice. The study involved 44 promising varieties of Indica rices collected from geographically distant places and adapted to irrigated and aerobic agro-ecosystems. Quality data for ...

  12. Effect of integration of cultural, botanical, and chemical methods of ...

    African Journals Online (AJOL)

    A field experiment was conducted from November 2011 to June 2013 to evaluate the effects of botanical, cultural, and chemical methods on termite colony survival, crop and wooden damage, and other biological activities in Ghimbi district of western Ethiopia. The termite mounds were dug and the following treatments were ...

  13. Force measuring valve assemblies, systems including such valve assemblies and related methods

    Science.gov (United States)

    DeWall, Kevin George [Pocatello, ID; Garcia, Humberto Enrique [Idaho Falls, ID; McKellar, Michael George [Idaho Falls, ID

    2012-04-17

    Methods of evaluating a fluid condition may include stroking a valve member and measuring a force acting on the valve member during the stroke. Methods of evaluating a fluid condition may include measuring a force acting on a valve member in the presence of fluid flow over a period of time and evaluating at least one of the frequency of changes in the measured force over the period of time and the magnitude of the changes in the measured force over the period of time to identify the presence of an anomaly in a fluid flow and, optionally, its estimated location. Methods of evaluating a valve condition may include directing a fluid flow through a valve while stroking a valve member, measuring a force acting on the valve member during the stroke, and comparing the measured force to a reference force. Valve assemblies and related systems are also disclosed.

  14. Recycling of poly(ethylene terephthalate – A review focusing on chemical methods

    Directory of Open Access Journals (Sweden)

    B. Geyer

    2016-07-01

    Full Text Available Recycling of poly(ethylene terephthalate (PET is of crucial importance, since worldwide amounts of PETwaste increase rapidly due to its widespread applications. Hence, several methods have been developed, like energetic, material, thermo-mechanical and chemical recycling of PET. Most frequently, PET-waste is incinerated for energy recovery, used as additive in concrete composites or glycolysed to yield mixtures of monomers and undefined oligomers. While energetic and thermo-mechanical recycling entail downcycling of the material, chemical recycling requires considerable amounts of chemicals and demanding processing steps entailing toxic and ecological issues. This review provides a thorough survey of PET-recycling including energetic, material, thermo-mechanical and chemical methods. It focuses on chemical methods describing important reaction parameters and yields of obtained reaction products. While most methods yield monomers, only a few yield undefined low molecular weight oligomers for impaired applications (dispersants or plasticizers. Further, the present work presents an alternative chemical recycling method of PET in comparison to existing chemical methods.

  15. Electrochemical and chemical methods of metallizing plastic films

    OpenAIRE

    Chapples, J.

    1991-01-01

    This thesis describes two novel techniques for the metallization of non-electroactive polymer films and thicker sectioned polyethylene and nylon substrates. In the first approach, non-electroactive polymer substrates were impregnated with surface layers of polypyrrole and polyaniline, using electrochemical and chemical methods of polymerization. The relative merits of both these approaches are discussed and compared with other methods in the literature. The resultant composi...

  16. Development method of Hybrid Energy Storage System, including PEM fuel cell and a battery

    International Nuclear Information System (INIS)

    Ustinov, A; Khayrullina, A; Khmelik, M; Sveshnikova, A; Borzenko, V

    2016-01-01

    Development of fuel cell (FC) and hydrogen metal-hydride storage (MH) technologies continuously demonstrate higher efficiency rates and higher safety, as hydrogen is stored at low pressures of about 2 bar in a bounded state. A combination of a FC/MH system with an electrolyser, powered with a renewable source, allows creation of an almost fully autonomous power system, which could potentially replace a diesel-generator as a back-up power supply. However, the system must be extended with an electro-chemical battery to start-up the FC and compensate the electric load when FC fails to deliver the necessary power. Present paper delivers the results of experimental and theoretical investigation of a hybrid energy system, including a proton exchange membrane (PEM) FC, MH- accumulator and an electro-chemical battery, development methodology for such systems and the modelling of different battery types, using hardware-in-the-loop approach. The economic efficiency of the proposed solution is discussed using an example of power supply of a real town of Batamai in Russia. (paper)

  17. Development method of Hybrid Energy Storage System, including PEM fuel cell and a battery

    Science.gov (United States)

    Ustinov, A.; Khayrullina, A.; Borzenko, V.; Khmelik, M.; Sveshnikova, A.

    2016-09-01

    Development of fuel cell (FC) and hydrogen metal-hydride storage (MH) technologies continuously demonstrate higher efficiency rates and higher safety, as hydrogen is stored at low pressures of about 2 bar in a bounded state. A combination of a FC/MH system with an electrolyser, powered with a renewable source, allows creation of an almost fully autonomous power system, which could potentially replace a diesel-generator as a back-up power supply. However, the system must be extended with an electro-chemical battery to start-up the FC and compensate the electric load when FC fails to deliver the necessary power. Present paper delivers the results of experimental and theoretical investigation of a hybrid energy system, including a proton exchange membrane (PEM) FC, MH- accumulator and an electro-chemical battery, development methodology for such systems and the modelling of different battery types, using hardware-in-the-loop approach. The economic efficiency of the proposed solution is discussed using an example of power supply of a real town of Batamai in Russia.

  18. Electrode assemblies, plasma apparatuses and systems including electrode assemblies, and methods for generating plasma

    Science.gov (United States)

    Kong, Peter C; Grandy, Jon D; Detering, Brent A; Zuck, Larry D

    2013-09-17

    Electrode assemblies for plasma reactors include a structure or device for constraining an arc endpoint to a selected area or region on an electrode. In some embodiments, the structure or device may comprise one or more insulating members covering a portion of an electrode. In additional embodiments, the structure or device may provide a magnetic field configured to control a location of an arc endpoint on the electrode. Plasma generating modules, apparatus, and systems include such electrode assemblies. Methods for generating a plasma include covering at least a portion of a surface of an electrode with an electrically insulating member to constrain a location of an arc endpoint on the electrode. Additional methods for generating a plasma include generating a magnetic field to constrain a location of an arc endpoint on an electrode.

  19. Including mixed methods research in systematic reviews: Examples from qualitative syntheses in TB and malaria control

    Science.gov (United States)

    2012-01-01

    Background Health policy makers now have access to a greater number and variety of systematic reviews to inform different stages in the policy making process, including reviews of qualitative research. The inclusion of mixed methods studies in systematic reviews is increasing, but these studies pose particular challenges to methods of review. This article examines the quality of the reporting of mixed methods and qualitative-only studies. Methods We used two completed systematic reviews to generate a sample of qualitative studies and mixed method studies in order to make an assessment of how the quality of reporting and rigor of qualitative-only studies compares with that of mixed-methods studies. Results Overall, the reporting of qualitative studies in our sample was consistently better when compared with the reporting of mixed methods studies. We found that mixed methods studies are less likely to provide a description of the research conduct or qualitative data analysis procedures and less likely to be judged credible or provide rich data and thick description compared with standalone qualitative studies. Our time-related analysis shows that for both types of study, papers published since 2003 are more likely to report on the study context, describe analysis procedures, and be judged credible and provide rich data. However, the reporting of other aspects of research conduct (i.e. descriptions of the research question, the sampling strategy, and data collection methods) in mixed methods studies does not appear to have improved over time. Conclusions Mixed methods research makes an important contribution to health research in general, and could make a more substantial contribution to systematic reviews. Through our careful analysis of the quality of reporting of mixed methods and qualitative-only research, we have identified areas that deserve more attention in the conduct and reporting of mixed methods research. PMID:22545681

  20. A novel technique for including surface tension in PLIC-VOF methods

    Energy Technology Data Exchange (ETDEWEB)

    Meier, M.; Yadigaroglu, G. [Swiss Federal Institute of Technology, Nuclear Engineering Lab. ETH-Zentrum, CLT, Zurich (Switzerland); Smith, B. [Paul Scherrer Inst. (PSI), Villigen (Switzerland). Lab. for Thermal-Hydraulics

    2002-02-01

    Various versions of Volume-of-Fluid (VOF) methods have been used successfully for the numerical simulation of gas-liquid flows with an explicit tracking of the phase interface. Of these, Piecewise-Linear Interface Construction (PLIC-VOF) appears as a fairly accurate, although somewhat more involved variant. Including effects due to surface tension remains a problem, however. The most prominent methods, Continuum Surface Force (CSF) of Brackbill et al. and the method of Zaleski and co-workers (both referenced later), both induce spurious or 'parasitic' currents, and only moderate accuracy in regards to determining the curvature. We present here a new method to determine curvature accurately using an estimator function, which is tuned with a least-squares-fit against reference data. Furthermore, we show how spurious currents may be drastically reduced using the reconstructed interfaces from the PLIC-VOF method. (authors)

  1. Wireless Chemical Sensor and Sensing Method for Use Therewith

    Science.gov (United States)

    Woodard, Stanley E. (Inventor); Oglesby, Donald M. (Inventor); Taylor, Bryant D. (Inventor)

    2016-01-01

    A wireless chemical sensor includes an electrical conductor and a material separated therefrom by an electric insulator. The electrical conductor is an unconnected open-circuit shaped for storage of an electric field and a magnetic field. In the presence of a time-varying magnetic field, the first electrical conductor resonates to generate harmonic electric and magnetic field responses. The material is positioned at a location lying within at least one of the electric and magnetic field responses so-generated. The material changes in electrical conductivity in the presence of a chemical-of-interest.

  2. Comparison of different methods to include recycling in LCAs of aluminium cans and disposable polystyrene cups.

    Science.gov (United States)

    van der Harst, Eugenie; Potting, José; Kroeze, Carolien

    2016-02-01

    Many methods have been reported and used to include recycling in life cycle assessments (LCAs). This paper evaluates six widely used methods: three substitution methods (i.e. substitution based on equal quality, a correction factor, and alternative material), allocation based on the number of recycling loops, the recycled-content method, and the equal-share method. These six methods were first compared, with an assumed hypothetical 100% recycling rate, for an aluminium can and a disposable polystyrene (PS) cup. The substitution and recycled-content method were next applied with actual rates for recycling, incineration and landfilling for both product systems in selected countries. The six methods differ in their approaches to credit recycling. The three substitution methods stimulate the recyclability of the product and assign credits for the obtained recycled material. The choice to either apply a correction factor, or to account for alternative substituted material has a considerable influence on the LCA results, and is debatable. Nevertheless, we prefer incorporating quality reduction of the recycled material by either a correction factor or an alternative substituted material over simply ignoring quality loss. The allocation-on-number-of-recycling-loops method focusses on the life expectancy of material itself, rather than on a specific separate product. The recycled-content method stimulates the use of recycled material, i.e. credits the use of recycled material in products and ignores the recyclability of the products. The equal-share method is a compromise between the substitution methods and the recycled-content method. The results for the aluminium can follow the underlying philosophies of the methods. The results for the PS cup are additionally influenced by the correction factor or credits for the alternative material accounting for the drop in PS quality, the waste treatment management (recycling rate, incineration rate, landfilling rate), and the

  3. Methods of using structures including catalytic materials disposed within porous zeolite materials to synthesize hydrocarbons

    Science.gov (United States)

    Rollins, Harry W [Idaho Falls, ID; Petkovic, Lucia M [Idaho Falls, ID; Ginosar, Daniel M [Idaho Falls, ID

    2011-02-01

    Catalytic structures include a catalytic material disposed within a zeolite material. The catalytic material may be capable of catalyzing a formation of methanol from carbon monoxide and/or carbon dioxide, and the zeolite material may be capable of catalyzing a formation of hydrocarbon molecules from methanol. The catalytic material may include copper and zinc oxide. The zeolite material may include a first plurality of pores substantially defined by a crystal structure of the zeolite material and a second plurality of pores dispersed throughout the zeolite material. Systems for synthesizing hydrocarbon molecules also include catalytic structures. Methods for synthesizing hydrocarbon molecules include contacting hydrogen and at least one of carbon monoxide and carbon dioxide with such catalytic structures. Catalytic structures are fabricated by forming a zeolite material at least partially around a template structure, removing the template structure, and introducing a catalytic material into the zeolite material.

  4. Manual of selected physico-chemical analytical methods. IV

    International Nuclear Information System (INIS)

    Beran, M.; Klosova, E.; Krtil, J.; Sus, F.; Kuvik, V.; Vrbova, L.; Hamplova, M.; Lengyel, J.; Kelnar, L.; Zakouril, K.

    1990-11-01

    The Central Testing Laboratory of the Nuclear Research Institute at Rez has for a decade been participating in the development of analytical procedures and has been providing analyses of samples of different types and origin. The analytical procedures developed have been published in special journals and a number of them in the Manuals of analytical methods, in three parts. The 4th part of the Manual contains selected physico-chemical methods developed or modified by the Laboratory in the years 1986-1990 within the project ''Development of physico-chemical analytical methods''. In most cases, techniques are involved for non-nuclear applications. Some can find wider applications, especially in analyses of environmental samples. Others have been developed for specific cases of sample analyses or require special instrumentation (mass spectrometer), which partly restricts their applicability by other institutions. (author)

  5. Including mixed methods research in systematic reviews: examples from qualitative syntheses in TB and malaria control.

    Science.gov (United States)

    Atkins, Salla; Launiala, Annika; Kagaha, Alexander; Smith, Helen

    2012-04-30

    Health policy makers now have access to a greater number and variety of systematic reviews to inform different stages in the policy making process, including reviews of qualitative research. The inclusion of mixed methods studies in systematic reviews is increasing, but these studies pose particular challenges to methods of review. This article examines the quality of the reporting of mixed methods and qualitative-only studies. We used two completed systematic reviews to generate a sample of qualitative studies and mixed method studies in order to make an assessment of how the quality of reporting and rigor of qualitative-only studies compares with that of mixed-methods studies. Overall, the reporting of qualitative studies in our sample was consistently better when compared with the reporting of mixed methods studies. We found that mixed methods studies are less likely to provide a description of the research conduct or qualitative data analysis procedures and less likely to be judged credible or provide rich data and thick description compared with standalone qualitative studies. Our time-related analysis shows that for both types of study, papers published since 2003 are more likely to report on the study context, describe analysis procedures, and be judged credible and provide rich data. However, the reporting of other aspects of research conduct (i.e. descriptions of the research question, the sampling strategy, and data collection methods) in mixed methods studies does not appear to have improved over time. Mixed methods research makes an important contribution to health research in general, and could make a more substantial contribution to systematic reviews. Through our careful analysis of the quality of reporting of mixed methods and qualitative-only research, we have identified areas that deserve more attention in the conduct and reporting of mixed methods research.

  6. Method for innovative synthesis-design of chemical process flowsheets

    DEFF Research Database (Denmark)

    Kumar Tula, Anjan; Gani, Rafiqul

    Chemical process synthesis-design involve the identification of the processing route to reach a desired product from a specified set of raw materials, design of the operations involved in the processing route, the calculations of utility requirements, the calculations of waste and emission...... to the surrounding and many more. Different methods (knowledge-based [1], mathematical programming [2], hybrid, etc.) have been proposed and are also currently employed to solve these synthesis-design problems. D’ Anterroches [3] proposed a group contribution based approach to solve the synthesis-design problem...... of chemical processes, where, chemical process flowsheets could be synthesized in the same way as atoms or groups of atoms are synthesized to form molecules in computer aided molecular design (CAMD) techniques [4]. That, from a library of building blocks (functional process-groups) and a set of rules to join...

  7. Including Bioconcentration Kinetics for the Prioritization and Interpretation of Regulatory Aquatic Toxicity Tests of Highly Hydrophobic Chemicals

    DEFF Research Database (Denmark)

    Kwon, Jung-Hwan; Lee, So-Young; Kang, Hyun-Joong

    2016-01-01

    experiments. In this work, internal concentrations of highly hydrophobic chemicals were predicted for standard acute ecotoxicity tests at three trophic levels, algae, invertebrate, and fish. As demonstrated by comparison with maximum aqueous concentrations at water solubility, chemicals with an octanol...

  8. 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

  9. Complete Tangent Stiffness for eXtended Finite Element Method by including crack growth parameters

    DEFF Research Database (Denmark)

    Mougaard, J.F.; Poulsen, P.N.; Nielsen, L.O.

    2013-01-01

    the crack geometry parameters, such as the crack length and the crack direction directly in the virtual work formulation. For efficiency, it is essential to obtain a complete tangent stiffness. A new method in this work is presented to include an incremental form the crack growth parameters on equal terms......The eXtended Finite Element Method (XFEM) is a useful tool for modeling the growth of discrete cracks in structures made of concrete and other quasi‐brittle and brittle materials. However, in a standard application of XFEM, the tangent stiffness is not complete. This is a result of not including...... with the degrees of freedom in the FEM‐equations. The complete tangential stiffness matrix is based on the virtual work together with the constitutive conditions at the crack tip. Introducing the crack growth parameters as direct unknowns, both equilibrium equations and the crack tip criterion can be handled...

  10. Method and apparatus for controlling gas evolution from chemical reactions

    Science.gov (United States)

    Skorpik, James R.; Dodson, Michael G.

    1999-01-01

    The present invention is directed toward monitoring a thermally driven gas evolving chemical reaction with an acoustic apparatus. Signals from the acoustic apparatus are used to control a heater to prevent a run-away condition. A digestion module in combination with a robotic arm further automate physical handling of sample material reaction vessels. The invention is especially useful for carrying out sample procedures defined in EPA Methods SW-846.

  11. Earthquake analysis of structures including structure-soil interaction by a substructure method

    International Nuclear Information System (INIS)

    Chopra, A.K.; Guttierrez, J.A.

    1977-01-01

    A general substructure method for analysis of response of nuclear power plant structures to earthquake ground motion, including the effects of structure-soil interaction, is summarized. The method is applicable to complex structures idealized as finite element systems and the soil region treated as either a continuum, for example as a viscoelastic halfspace, or idealized as a finite element system. The halfspace idealization permits reliable analysis for sites where essentially similar soils extend to large depths and there is no rigid boundary such as soil-rock interface. For sites where layers of soft soil are underlain by rock at shallow depth, finite element idealization of the soil region is appropriate; in this case, the direct and substructure methods would lead to equivalent results but the latter provides the better alternative. Treating the free field motion directly as the earthquake input in the substructure method eliminates the deconvolution calculations and the related assumption -regarding type and direction of earthquake waves- required in the direct method. The substructure method is computationally efficient because the two substructures-the structure and the soil region- are analyzed separately; and, more important, it permits taking advantage of the important feature that response to earthquake ground motion is essentially contained in the lower few natural modes of vibration of the structure on fixed base. For sites where essentially similar soils extend to large depths and there is no obvious rigid boundary such as a soil-rock interface, numerical results for earthquake response of a nuclear reactor structure are presented to demonstrate that the commonly used finite element method may lead to unacceptable errors; but the substructure method leads to reliable results

  12. Method for contamination control and barrier apparatus with filter for containing waste materials that include dangerous particulate matter

    Science.gov (United States)

    Pinson, Paul A.

    1998-01-01

    A container for hazardous waste materials that includes air or other gas carrying dangerous particulate matter has incorporated in barrier material, preferably in the form of a flexible sheet, one or more filters for the dangerous particulate matter sealably attached to such barrier material. The filter is preferably a HEPA type filter and is preferably chemically bonded to the barrier materials. The filter or filters are preferably flexibly bonded to the barrier material marginally and peripherally of the filter or marginally and peripherally of air or other gas outlet openings in the barrier material, which may be a plastic bag. The filter may be provided with a backing panel of barrier material having an opening or openings for the passage of air or other gas into the filter or filters. Such backing panel is bonded marginally and peripherally thereof to the barrier material or to both it and the filter or filters. A coupling or couplings for deflating and inflating the container may be incorporated. Confining a hazardous waste material in such a container, rapidly deflating the container and disposing of the container, constitutes one aspect of the method of the invention. The chemical bonding procedure for producing the container constitutes another aspect of the method of the invention.

  13. Method for contamination control and barrier apparatus with filter for containing waste materials that include dangerous particulate matter

    International Nuclear Information System (INIS)

    Pinson, P.A.

    1998-01-01

    A container for hazardous waste materials that includes air or other gas carrying dangerous particulate matter has incorporated barrier material, preferably in the form of a flexible sheet, and one or more filters for the dangerous particulate matter sealably attached to such barrier material. The filter is preferably a HEPA type filter and is preferably chemically bonded to the barrier materials. The filter or filters are preferably flexibly bonded to the barrier material marginally and peripherally of the filter or marginally and peripherally of air or other gas outlet openings in the barrier material, which may be a plastic bag. The filter may be provided with a backing panel of barrier material having an opening or openings for the passage of air or other gas into the filter or filters. Such backing panel is bonded marginally and peripherally thereof to the barrier material or to both it and the filter or filters. A coupling or couplings for deflating and inflating the container may be incorporated. Confining a hazardous waste material in such a container, rapidly deflating the container and disposing of the container, constitutes one aspect of the method of the invention. The chemical bonding procedure for producing the container constitutes another aspect of the method of the invention. 3 figs

  14. Study on magnetite nanoparticles synthesized by chemical method

    International Nuclear Information System (INIS)

    Pei Wenli; Kumada, H.; Natusme, T.; Saito, H.; Ishio, S.

    2007-01-01

    Magnetite nanoparticles with controlled size were synthesized by chemical method. Higher deposition temperature and a rapid-raising temperature procedure are favorable to particle size distribution and fabrication of monodisperse nanoparticles. The larger nanoparticles can be synthesized by the two-step method. The large nanoparticle (up to 25 nm) without agglomeration was successfully produced. The saturation magnetization of 11 nm magnetite particles was 45 emu/g at room temperature, which is smaller than that of bulk magnetite due to surface effect. Hysteresis of the magnetite nanoparticle was very small, indicating superparamagnetic behavior. The magnetic domains of the 11 nm magnetite nanoparticles were successfully observed by MFM

  15. Development of a Benchtop Baking Method for Chemically Leavened Crackers

    Science.gov (United States)

    Traditionally, the baking performance of soft wheat flours has been evaluated by well-established benchtop cookie-baking methods. In contrast, a benchtop cracker-baking method has not been widely explored or implemented as an official method, due to hurdles including the difficulty in finding ideal...

  16. Spine surgeon's kinematics during discectomy, part II: operating table height and visualization methods, including microscope.

    Science.gov (United States)

    Park, Jeong Yoon; Kim, Kyung Hyun; Kuh, Sung Uk; Chin, Dong Kyu; Kim, Keun Su; Cho, Yong Eun

    2014-05-01

    Surgeon spine angle during surgery was studied ergonomically and the kinematics of the surgeon's spine was related with musculoskeletal fatigue and pain. Spine angles varied depending on operation table height and visualization method, and in a previous paper we showed that the use of a loupe and a table height at the midpoint between the umbilicus and the sternum are optimal for reducing musculoskeletal loading. However, no studies have previously included a microscope as a possible visualization method. The objective of this study is to assess differences in surgeon spine angles depending on operating table height and visualization method, including microscope. We enrolled 18 experienced spine surgeons for this study, who each performed a discectomy using a spine surgery simulator. Three different methods were used to visualize the surgical field (naked eye, loupe, microscope) and three different operating table heights (anterior superior iliac spine, umbilicus, the midpoint between the umbilicus and the sternum) were studied. Whole spine angles were compared for three different views during the discectomy simulation: midline, ipsilateral, and contralateral. A 16-camera optoelectronic motion analysis system was used, and 16 markers were placed from the head to the pelvis. Lumbar lordosis, thoracic kyphosis, cervical lordosis, and occipital angle were compared between the different operating table heights and visualization methods as well as a natural standing position. Whole spine angles differed significantly depending on visualization method. All parameters were closer to natural standing values when discectomy was performed with a microscope, and there were no differences between the naked eye and the loupe. Whole spine angles were also found to differ from the natural standing position depending on operating table height, and became closer to natural standing position values as the operating table height increased, independent of the visualization method

  17. Investigation of chemical equilibrium kinetics by the electromigration method

    International Nuclear Information System (INIS)

    Bozhikov, G.A.; Ivanov, P.I.; Maslov, O.D.; Dmitriev, S.N.; Bontchev, G.D.; Milanov, M.V.

    2003-01-01

    The measurement of the chemical reaction rates for complex formation as well as hydrolysis type reactions by the method of horizontal zone electrophoresis is outlined. The correlation between chemical equilibrium kinetics and electrodiffusion processes in a constant d.c. electric field is described. In model electromigration experiments the reaction rate constant of the formation a complex by Hf(IV) and diethylenetriaminepentaacetic acid (DTPA) is determined. The electrophoretic mobility, diffusion coefficient and stability constant of the [HfDTPA] - complex are calculated, taking into account experimental electrophoretic data obtained at 298.15±0.05 K and constant ionic strength. No-carrier-added 175 Hf radionuclide was used in electromigration experiments at concentrations of 10 -10 -10 -11 M. (orig.)

  18. Method for conversion of carbohydrate polymers to value-added chemical products

    Science.gov (United States)

    Zhang, Zongchao C [Norwood, NJ; Brown, Heather M [Kennewick, WA; Su, Yu [Richland, WA

    2012-02-07

    Methods are described for conversion of carbohydrate polymers in ionic liquids, including cellulose, that yield value-added chemicals including, e.g., glucose and 5-hydroxylmethylfurfural (HMF) at temperatures below 120.degree. C. Catalyst compositions that include various mixed metal halides are described that are selective for specified products with yields, e.g., of up to about 56% in a single step process.

  19. Earthquake analysis of structures including structure-soil interaction by a substructure method

    International Nuclear Information System (INIS)

    Chopra, A.K.; Guttierrez, J.A.

    1977-01-01

    A general substructure method for analysis of response of nuclear power plant structures to earthquake ground motion, including the effects of structure-soil interaction, is summarized. The method is applicable to complex structures idealized as finite element systems and the soil region treated as either a continuum, for example as a viscoelastic halfspace, or idealized as a finite element system. The halfspace idealization permits reliable analysis for sites where essentially similar soils extend to large depths and there is no rigid boundary such as soil-rock interface. For sites where layers of soft soil are underlain by rock at shallow depth, finite element idealization of the soil region is appropriate; in this case, the direct and substructure methods would lead to equivalent results but the latter provides the better alternative. Treating the free field motion directly as the earthquake input in the substructure eliminates the deconvolution calculations and the related assumption-regarding type and direction of earthquake waves-required in the direct method. (Auth.)

  20. Method and apparatus for controlling a powertrain system including a multi-mode transmission

    Science.gov (United States)

    Hessell, Steven M.; Morris, Robert L.; McGrogan, Sean W.; Heap, Anthony H.; Mendoza, Gil J.

    2015-09-08

    A powertrain including an engine and torque machines is configured to transfer torque through a multi-mode transmission to an output member. A method for controlling the powertrain includes employing a closed-loop speed control system to control torque commands for the torque machines in response to a desired input speed. Upon approaching a power limit of a power storage device transferring power to the torque machines, power limited torque commands are determined for the torque machines in response to the power limit and the closed-loop speed control system is employed to determine an engine torque command in response to the desired input speed and the power limited torque commands for the torque machines.

  1. Consolidation of the formation sand by chemical methods

    Directory of Open Access Journals (Sweden)

    Mariana Mihočová

    2006-10-01

    Full Text Available The sand control by consolidation involves the process of injecting chemicals into the naturally unconsolidated formation to provide an in situ grain-to-grain cementation. The sand consolidation chemicals are available for some 30 years. Several types of consolidating material were tried. Presently available systems utilize solidified plastics to provide the cementation. These systems include phenol resin, phenol-formaldehyde, epoxy, furan and phenolic-furfuryl.The sand consolidation with the steam injection is a novel technique. This process provides a highly alkaline liquid phase and temperatures to 300 °C to geochemically create cements by interacting with the dirty sand.While the formation consolidation has widely applied, our experience has proved a high level of success.

  2. An experimental design method leading to chemical Turing patterns.

    Science.gov (United States)

    Horváth, Judit; Szalai, István; De Kepper, Patrick

    2009-05-08

    Chemical reaction-diffusion patterns often serve as prototypes for pattern formation in living systems, but only two isothermal single-phase reaction systems have produced sustained stationary reaction-diffusion patterns so far. We designed an experimental method to search for additional systems on the basis of three steps: (i) generate spatial bistability by operating autoactivated reactions in open spatial reactors; (ii) use an independent negative-feedback species to produce spatiotemporal oscillations; and (iii) induce a space-scale separation of the activatory and inhibitory processes with a low-mobility complexing agent. We successfully applied this method to a hydrogen-ion autoactivated reaction, the thiourea-iodate-sulfite (TuIS) reaction, and noticeably produced stationary hexagonal arrays of spots and parallel stripes of pH patterns attributed to a Turing bifurcation. This method could be extended to biochemical reactions.

  3. A method of refining aromatic hydrocarbons from coal chemical production

    Energy Technology Data Exchange (ETDEWEB)

    Zieborak, K.; Koprowski, A.; Ratajczak, W.

    1979-10-01

    A method is disclosed for refining aromatic hydrocarbons of coal chemical production by contact of liquid aromatic hydrocarbons and their mixtures with a strongly acid macroporous sulfocationite in the H-form at atmospheric pressure and high temperature. The method is distinguished in that the aromatic hydrocarbons and their mixtures, from which alkali compounds have already been removed, are supplied for refinement with the sulfocationite with simultaneous addition of olefin derivatives of aromatic hydrocarbons, followed by separation of pure hydrocarbons by rectification. Styrene or alpha-methylstyrene is used as the olefin derivatives of the aromatic hydrocarbons. The method is performed in several stages with addition of olefin derivatives of aromatic hydrocarbons at each stage.

  4. A frequency domain linearized Navier-Stokes method including acoustic damping by eddy viscosity using RANS

    Science.gov (United States)

    Holmberg, Andreas; Kierkegaard, Axel; Weng, Chenyang

    2015-06-01

    In this paper, a method for including damping of acoustic energy in regions of strong turbulence is derived for a linearized Navier-Stokes method in the frequency domain. The proposed method is validated and analyzed in 2D only, although the formulation is fully presented in 3D. The result is applied in a study of the linear interaction between the acoustic and the hydrodynamic field in a 2D T-junction, subject to grazing flow at Mach 0.1. Part of the acoustic energy at the upstream edge of the junction is shed as harmonically oscillating disturbances, which are conveyed across the shear layer over the junction, where they interact with the acoustic field. As the acoustic waves travel in regions of strong shear, there is a need to include the interaction between the background turbulence and the acoustic field. For this purpose, the oscillation of the background turbulence Reynold's stress, due to the acoustic field, is modeled using an eddy Newtonian model assumption. The time averaged flow is first solved for using RANS along with a k-ε turbulence model. The spatially varying turbulent eddy viscosity is then added to the spatially invariant kinematic viscosity in the acoustic set of equations. The response of the 2D T-junction to an incident acoustic field is analyzed via a plane wave scattering matrix model, and the result is compared to experimental data for a T-junction of rectangular ducts. A strong improvement in the agreement between calculation and experimental data is found when the modification proposed in this paper is implemented. Discrepancies remaining are likely due to inaccuracies in the selected turbulence model, which is known to produce large errors e.g. for flows with significant rotation, which the grazing flow across the T-junction certainly is. A natural next step is therefore to test the proposed methodology together with more sophisticated turbulence models.

  5. Reliability and limitation of various diagnostic methods including nuclear medicine in myocardial disease

    International Nuclear Information System (INIS)

    Tokuyasu, Yoshiki; Kusakabe, Kiyoko; Yamazaki, Toshio

    1981-01-01

    Electrocardiography (ECG), echocardiography, nuclear method, cardiac catheterization, left ventriculography and endomyocardial biopsy (biopsy) were performed in 40 cases of cardiomyopathy (CM), 9 of endocardial fibroelastosis and 19 of specific heart muscle disease, and the usefulness and limitation of each method was comparatively estimated. In CM, various methods including biopsy were performed. The 40 patients were classified into 3 groups, i.e., hypertrophic (17), dilated (20) and non-hypertrophic.non-dilated (3) on the basis of left ventricular ejection fraction and hypertrophy of the ventricular wall. The hypertrophic group was divided into 4 subgroups: 9 septal, 4 apical, 2 posterior and 2 anterior. The nuclear study is useful in assessing the site of the abnormal ventricular thickening, perfusion defect and ventricular function. Echocardiography is most useful in detecting asymmetric septal hypertrophy. The biopsy gives the sole diagnostic clue, especially in non-hypertrophic.non-dilated cardiomyopathy. ECG is useful in all cases but correlation with the site of disproportional hypertrophy was not obtained. (J.P.N.)

  6. A method for including external feed in depletion calculations with CRAM and implementation into ORIGEN

    International Nuclear Information System (INIS)

    Isotalo, A.E.; Wieselquist, W.A.

    2015-01-01

    Highlights: • A method for handling external feed in depletion calculations with CRAM. • Source term can have polynomial or exponentially decaying time-dependence. • CRAM with source term and adjoint capability implemented to ORIGEN in SCALE. • The new solver is faster and more accurate than the original solver of ORIGEN. - Abstract: A method for including external feed with polynomial time dependence in depletion calculations with the Chebyshev Rational Approximation Method (CRAM) is presented and the implementation of CRAM to the ORIGEN module of the SCALE suite is described. In addition to being able to handle time-dependent feed rates, the new solver also adds the capability to perform adjoint calculations. Results obtained with the new CRAM solver and the original depletion solver of ORIGEN are compared to high precision reference calculations, which shows the new solver to be orders of magnitude more accurate. Furthermore, in most cases, the new solver is up to several times faster due to not requiring similar substepping as the original one

  7. Improved Riccati Transfer Matrix Method for Free Vibration of Non-Cylindrical Helical Springs Including Warping

    Directory of Open Access Journals (Sweden)

    A.M. Yu

    2012-01-01

    Full Text Available Free vibration equations for non-cylindrical (conical, barrel, and hyperboloidal types helical springs with noncircular cross-sections, which consist of 14 first-order ordinary differential equations with variable coefficients, are theoretically derived using spatially curved beam theory. In the formulation, the warping effect upon natural frequencies and vibrating mode shapes is first studied in addition to including the rotary inertia, the shear and axial deformation influences. The natural frequencies of the springs are determined by the use of improved Riccati transfer matrix method. The element transfer matrix used in the solution is calculated using the Scaling and Squaring method and Pad'e approximations. Three examples are presented for three types of springs with different cross-sectional shapes under clamped-clamped boundary condition. The accuracy of the proposed method has been compared with the FEM results using three-dimensional solid elements (Solid 45 in ANSYS code. Numerical results reveal that the warping effect is more pronounced in the case of non-cylindrical helical springs than that of cylindrical helical springs, which should be taken into consideration in the free vibration analysis of such springs.

  8. Methods of chemical and phase composition analysis of gallstones

    Science.gov (United States)

    Suvorova, E. I.; Pantushev, V. V.; Voloshin, A. E.

    2017-11-01

    This review presents the instrumental methods used for chemical and phase composition investigation of gallstones. A great body of data has been collected in the literature on the presence of elements and their concentrations, obtained by fluorescence microscopy, X-ray fluorescence spectroscopy, neutron activation analysis, proton (particle) induced X-ray emission, atomic absorption spectroscopy, high-resolution gamma-ray spectrometry, electron paramagnetic resonance. Structural methods—powder X-ray diffraction, infrared spectroscopy, Raman spectroscopy—provide information about organic and inorganic phases in gallstones. Stone morphology was studied at the macrolevel with optical microscopy. Results obtained by analytical scanning and transmission electron microscopy with X-ray energy dispersive spectrometry are discussed. The chemical composition and structure of gallstones determine the strategy of removing stone from the body and treatment of patients: surgery or dissolution in the body. Therefore one chapter of the review describes the potential of dissolution methods. Early diagnosis and appropriate treatment of the disease depend on the development of clinical methods for in vivo investigation, which gave grounds to present the main characteristics and potential of ultrasonography (ultrasound scanning), magnetic resonance imaging, and X-ray computed tomography.

  9. AN ANALYTICAL METHOD FOR CHEMICAL SPECIATION OF SELENIUM IN SOIL

    Directory of Open Access Journals (Sweden)

    Constantin Luca

    2010-10-01

    Full Text Available Selenium is an essential microelement, sometimes redoubtable, through its beneficial role - risk depending on its concentration in the food chain, at low dose is an important nutrient in the life of humans and animals, contrary at high doses, it becomes toxic. Selenium may be find itself in the environment (soil, sediment, water in many forms (oxidized, reduced, organometallic which determine their mobility and toxicity. Determination of chemical speciation (identification of different chemical forms provides much more complete information for a better understanding of the behavior and the potential impact on the environment. In this work we present the results of methodological research on the extraction of sequential forms of selenium in the soil and the coupling of analytical methods capable of identifying very small amounts of selenium in soils An efficient scheme of sequential extractions forms of selenium (SES consisting in atomic absorption spectrometry coupled with hydride generation (HGAAS has been developed into five experimental steps, detailed in the paper. This operational scheme has been applied to the analysis of chemical speciation in the following areas: the Bărăgan Plain and Central Dobrogea of Romania.

  10. Use of ab initio quantum chemical methods in battery technology

    Energy Technology Data Exchange (ETDEWEB)

    Deiss, E [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1997-06-01

    Ab initio quantum chemistry can nowadays predict physical and chemical properties of molecules and solids. An attempt should be made to use this tool more widely for predicting technologically favourable materials. To demonstrate the use of ab initio quantum chemistry in battery technology, the theoretical energy density (energy per volume of active electrode material) and specific energy (energy per mass of active electrode material) of a rechargeable lithium-ion battery consisting of a graphite electrode and a nickel oxide electrode has been calculated with this method. (author) 1 fig., 1 tab., 7 refs.

  11. Synthesis of Lead Sulfide Nanoparticles by Chemical Precipitation Method

    International Nuclear Information System (INIS)

    Chongad, L S; Sharma, A; Banerjee, M; Jain, A

    2016-01-01

    Lead sulfide (PbS) nanoparticles were prepared by chemical precipitation method (CPM) with the assistance of H 2 S gas. The microstructure and morphology of the synthesized nanoparticles have been investigated using X-ray diffraction (XRD) and transmission electron microscopy (TEM). The XRD patterns of the PbS nanoparticles reveal formation of cubic phase. To investigate the quality of prepared nanoparticles, the particles size, lattice constant, strain, dislocation density etc. have been determined using XRD. TEM images reveal formation of cubic nanoparticles and the particle size determined from TEM images agree well with those from XRD. (paper)

  12. Cancer morbidity in British military veterans included in chemical warfare agent experiments at Porton Down: cohort study

    Science.gov (United States)

    Linsell, L; Brooks, C; Keegan, T J; Langdon, T; Doyle, P; Maconochie, N E S; Fletcher, T; Nieuwenhuijsen, M J; Beral, V

    2009-01-01

    Objective To determine cancer morbidity in members of the armed forces who took part in tests of chemical warfare agents from 1941 to 1989. Design Historical cohort study, with cohort members followed up to December 2004. Data source Archive of UK government research facility at Porton Down, UK military personnel records, and national death and cancer records. Participants All veterans included in the cohort study of mortality, excluding those known to have died or been lost to follow-up before 1 January 1971 when the UK cancer registration system commenced: 17 013 male members of the UK armed forces who took part in tests (Porton Down veterans) and a similar group of 16 520 men who did not (non-Porton Down veterans). Main outcome measures Cancer morbidity in each group of veterans; rate ratios, with 95% confidence intervals, adjusted for age group and calendar period. Results 3457 cancers were reported in the Porton Down veterans compared with 3380 cancers in the non-Porton Down veterans. While overall cancer morbidity was the same in both groups (rate ratio 1.00, 95% confidence interval 0.95 to 1.05), Porton Down veterans had higher rates of ill defined malignant neoplasms (1.12, 1.02 to 1.22), in situ neoplasms (1.45, 1.06 to 2.00), and those of uncertain or unknown behaviour (1.32, 1.01 to 1.73). Conclusion Overall cancer morbidity in Porton Down veterans was no different from that in non-Porton Down veterans. PMID:19318700

  13. SU-F-J-86: Method to Include Tissue Dose Response Effect in Deformable Image Registration

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, J; Liang, J; Chen, S; Qin, A; Yan, D [Beaumont Health Systeml, Royal Oak, MI (United States)

    2016-06-15

    Purpose: Organ changes shape and size during radiation treatment due to both mechanical stress and radiation dose response. However, the dose response induced deformation has not been considered in conventional deformable image registration (DIR). A novel DIR approach is proposed to include both tissue elasticity and radiation dose induced organ deformation. Methods: Assuming that organ sub-volume shrinkage was proportional to the radiation dose induced cell killing/absorption, the dose induced organ volume change was simulated applying virtual temperature on each sub-volume. Hence, both stress and heterogeneity temperature induced organ deformation. Thermal stress finite element method with organ surface boundary condition was used to solve deformation. Initial boundary correspondence on organ surface was created from conventional DIR. Boundary condition was updated by an iterative optimization scheme to minimize elastic deformation energy. The registration was validated on a numerical phantom. Treatment dose was constructed applying both the conventional DIR and the proposed method using daily CBCT image obtained from HN treatment. Results: Phantom study showed 2.7% maximal discrepancy with respect to the actual displacement. Compared with conventional DIR, subvolume displacement difference in a right parotid had the mean±SD (Min, Max) to be 1.1±0.9(−0.4∼4.8), −0.1±0.9(−2.9∼2.4) and −0.1±0.9(−3.4∼1.9)mm in RL/PA/SI directions respectively. Mean parotid dose and V30 constructed including the dose response induced shrinkage were 6.3% and 12.0% higher than those from the conventional DIR. Conclusion: Heterogeneous dose distribution in normal organ causes non-uniform sub-volume shrinkage. Sub-volume in high dose region has a larger shrinkage than the one in low dose region, therefore causing more sub-volumes to move into the high dose area during the treatment course. This leads to an unfavorable dose-volume relationship for the normal organ

  14. Metal-assisted chemical etch porous silicon formation method

    Science.gov (United States)

    Li, Xiuling; Bohn, Paul W.; Sweedler, Jonathan V.

    2004-09-14

    A thin discontinuous layer of metal such as Au, Pt, or Au/Pd is deposited on a silicon surface. The surface is then etched in a solution including HF and an oxidant for a brief period, as little as a couple seconds to one hour. A preferred oxidant is H.sub.2 O.sub.2. Morphology and light emitting properties of porous silicon can be selectively controlled as a function of the type of metal deposited, Si doping type, silicon doping level, and/or etch time. Electrical assistance is unnecessary during the chemical etching of the invention, which may be conducted in the presence or absence of illumination.

  15. Engine including hydraulically actuated valvetrain and method of valve overlap control

    Science.gov (United States)

    Cowgill, Joel [White Lake, MI

    2012-05-08

    An exhaust valve control method may include displacing an exhaust valve in communication with the combustion chamber of an engine to an open position using a hydraulic exhaust valve actuation system and returning the exhaust valve to a closed position using the hydraulic exhaust valve actuation assembly. During closing, the exhaust valve may be displaced for a first duration from the open position to an intermediate closing position at a first velocity by operating the hydraulic exhaust valve actuation assembly in a first mode. The exhaust valve may be displaced for a second duration greater than the first duration from the intermediate closing position to a fully closed position at a second velocity at least eighty percent less than the first velocity by operating the hydraulic exhaust valve actuation assembly in a second mode.

  16. Flexible barrier film, method of forming same, and organic electronic device including same

    Science.gov (United States)

    Blizzard, John; Tonge, James Steven; Weidner, William Kenneth

    2013-03-26

    A flexible barrier film has a thickness of from greater than zero to less than 5,000 nanometers and a water vapor transmission rate of no more than 1.times.10.sup.-2 g/m.sup.2/day at 22.degree. C. and 47% relative humidity. The flexible barrier film is formed from a composition, which comprises a multi-functional acrylate. The composition further comprises the reaction product of an alkoxy-functional organometallic compound and an alkoxy-functional organosilicon compound. A method of forming the flexible barrier film includes the steps of disposing the composition on a substrate and curing the composition to form the flexible barrier film. The flexible barrier film may be utilized in organic electronic devices.

  17. Zirconium-based alloys, nuclear fuel rods and nuclear reactors including such alloys, and related methods

    Science.gov (United States)

    Mariani, Robert Dominick

    2014-09-09

    Zirconium-based metal alloy compositions comprise zirconium, a first additive in which the permeability of hydrogen decreases with increasing temperatures at least over a temperature range extending from 350.degree. C. to 750.degree. C., and a second additive having a solubility in zirconium over the temperature range extending from 350.degree. C. to 750.degree. C. At least one of a solubility of the first additive in the second additive over the temperature range extending from 350.degree. C. to 750.degree. C. and a solubility of the second additive in the first additive over the temperature range extending from 350.degree. C. to 750.degree. C. is higher than the solubility of the second additive in zirconium over the temperature range extending from 350.degree. C. to 750.degree. C. Nuclear fuel rods include a cladding material comprising such metal alloy compositions, and nuclear reactors include such fuel rods. Methods are used to fabricate such zirconium-based metal alloy compositions.

  18. Chemical methods for the determination of composition of cryolite

    International Nuclear Information System (INIS)

    Shivarudrappa, V.; Patil, B.N.; Marathe, S.G.; Jain, H.C.

    1989-01-01

    Preparation of uranium and plutonium alloys containing aluminium involves the use of cryolite and many times, cryolite which may be contaminated with alpha activity has to be analysed for its purity. In view of this, chemical methods for the determination of composition of commercial cryolite samples have been developed. Methods are standardised for the determination of individual constituents of cryolite viz., aluminium, sodium, fluoride and major impurities, calcium and magnesium. Studies on the dissolution of the sample, effect of one or more components on the determination of the other and their elimination are carried out. Aluminium and sodium are determined gravimetrically as oxinate and triple acetate respectively. Fluoride is determined by a volumetric procedure after cation exchange separtion of soluble fluoride. Calcium and magnesium are determined by a sequential pH-metri titration. This report describes the details of the procedures and the results of these studies for two commercial cryolite samples. (author). 7 tabs

  19. Preparation of polymeric biomaterials with the aid of radiation-chemical methods

    International Nuclear Information System (INIS)

    Kabanov, Vitalii Ya

    1998-01-01

    The results of the application of radiation-chemical methods for the preparation of polymeric biomaterials are surveyed and treated systematically. The characteristic features of these methods and their advantages and disadvantages are indicated. The properties of polymeric biomaterials prepared using ionising radiation are examined. Particular attention is devoted to studies carried out during the last 10-15 years. The bibliography includes 492 references.

  20. Second-principles method for materials simulations including electron and lattice degrees of freedom

    Science.gov (United States)

    García-Fernández, Pablo; Wojdeł, Jacek C.; Íñiguez, Jorge; Junquera, Javier

    2016-05-01

    We present a first-principles-based (second-principles) scheme that permits large-scale materials simulations including both atomic and electronic degrees of freedom on the same footing. The method is based on a predictive quantum-mechanical theory—e.g., density functional theory—and its accuracy can be systematically improved at a very modest computational cost. Our approach is based on dividing the electron density of the system into a reference part—typically corresponding to the system's neutral, geometry-dependent ground state—and a deformation part—defined as the difference between the actual and reference densities. We then take advantage of the fact that the bulk part of the system's energy depends on the reference density alone; this part can be efficiently and accurately described by a force field, thus avoiding explicit consideration of the electrons. Then, the effects associated to the difference density can be treated perturbatively with good precision by working in a suitably chosen Wannier function basis. Further, the electronic model can be restricted to the bands of interest. All these features combined yield a very flexible and computationally very efficient scheme. Here we present the basic formulation of this approach, as well as a practical strategy to compute model parameters for realistic materials. We illustrate the accuracy and scope of the proposed method with two case studies, namely, the relative stability of various spin arrangements in NiO (featuring complex magnetic interactions in a strongly-correlated oxide) and the formation of a two-dimensional electron gas at the interface between band insulators LaAlO3 and SrTiO3 (featuring subtle electron-lattice couplings and screening effects). We conclude by discussing ways to overcome the limitations of the present approach (most notably, the assumption of a fixed bonding topology), as well as its many envisioned possibilities and future extensions.

  1. Aperture-Tolerant, Chemical-Based Methods to Reduce Channeling

    Energy Technology Data Exchange (ETDEWEB)

    Randall S. Seright

    2007-09-30

    This final technical progress report describes work performed from October 1, 2004, through May 16, 2007, for the project, 'Aperture-Tolerant, Chemical-Based Methods to Reduce Channeling'. We explored the potential of pore-filling gels for reducing excess water production from both fractured and unfractured production wells. Several gel formulations were identified that met the requirements--i.e., providing water residual resistance factors greater than 2,000 and ultimate oil residual resistance factors (F{sub rro}) of 2 or less. Significant oil throughput was required to achieve low F{sub rro} values, suggesting that gelant penetration into porous rock must be small (a few feet or less) for existing pore-filling gels to provide effective disproportionate permeability reduction. Compared with adsorbed polymers and weak gels, strong pore-filling gels can provide greater reliability and behavior that is insensitive to the initial rock permeability. Guidance is provided on where relative-permeability-modification/disproportionate-permeability-reduction treatments can be successfully applied for use in either oil or gas production wells. When properly designed and executed, these treatments can be successfully applied to a limited range of oilfield excessive-water-production problems. We examined whether gel rheology can explain behavior during extrusion through fractures. The rheology behavior of the gels tested showed a strong parallel to the results obtained from previous gel extrusion experiments. However, for a given aperture (fracture width or plate-plate separation), the pressure gradients measured during the gel extrusion experiments were much higher than anticipated from rheology measurements. Extensive experiments established that wall slip and first normal stress difference were not responsible for the pressure gradient discrepancy. To explain the discrepancy, we noted that the aperture for gel flow (for mobile gel wormholing through concentrated

  2. Applicability of a panel method, which includes nonlinear effects, to a forward-swept-wing aircraft

    Science.gov (United States)

    Ross, J. C.

    1984-01-01

    The ability of a lower order panel method VSAERO, to accurately predict the lift and pitching moment of a complete forward-swept-wing/canard configuration was investigated. The program can simulate nonlinear effects including boundary-layer displacement thickness, wake roll up, and to a limited extent, separated wakes. The predictions were compared with experimental data obtained using a small-scale model in the 7- by 10- Foot Wind Tunnel at NASA Ames Research Center. For the particular configuration under investigation, wake roll up had only a small effect on the force and moment predictions. The effect of the displacement thickness modeling was to reduce the lift curve slope slightly, thus bringing the predicted lift into good agreement with the measured value. Pitching moment predictions were also improved by the boundary-layer simulation. The separation modeling was found to be sensitive to user inputs, but appears to give a reasonable representation of a separated wake. In general, the nonlinear capabilities of the code were found to improve the agreement with experimental data. The usefullness of the code would be enhanced by improving the reliability of the separated wake modeling and by the addition of a leading edge separation model.

  3. Quantum confinement of lead titanate nanocrystals by wet chemical method

    Energy Technology Data Exchange (ETDEWEB)

    Kaviyarasu, K., E-mail: kaviyarasuloyolacollege@gmail.com [UNESCO-UNISA Africa Chair in Nanosciences/Nanotechnology Laboratories, College of Graduate Studies, University of South Africa (UNISA), Muckleneuk Ridge, P O Box 392, Pretoria (South Africa); Nanosciences African Network (NANOAFNET), Materials Research Department (MSD), iThemba LABS-National Research Foundation - NRF, 1 Old Faure Road, 7129, P O Box 722, Somerset West, Western Cape Province (South Africa); Manikandan, E., E-mail: maniphysics@gmail.com [Nanosciences African Network (NANOAFNET), Materials Research Department (MSD), iThemba LABS-National Research Foundation - NRF, 1 Old Faure Road, 7129, P O Box 722, Somerset West, Western Cape Province (South Africa); Central Research Laboratory, Sree Balaji Medical College & Hospital, Bharath University, Chrompet, Chennai, Tamil Nadu (India); Nuru, Z.Y. [UNESCO-UNISA Africa Chair in Nanosciences/Nanotechnology Laboratories, College of Graduate Studies, University of South Africa (UNISA), Muckleneuk Ridge, P O Box 392, Pretoria (South Africa); Nanosciences African Network (NANOAFNET), Materials Research Department (MSD), iThemba LABS-National Research Foundation - NRF, 1 Old Faure Road, 7129, P O Box 722, Somerset West, Western Cape Province (South Africa); Maaza, M., E-mail: likmaaz@gmail.com [UNESCO-UNISA Africa Chair in Nanosciences/Nanotechnology Laboratories, College of Graduate Studies, University of South Africa (UNISA), Muckleneuk Ridge, P O Box 392, Pretoria (South Africa); Nanosciences African Network (NANOAFNET), Materials Research Department (MSD), iThemba LABS-National Research Foundation - NRF, 1 Old Faure Road, 7129, P O Box 722, Somerset West, Western Cape Province (South Africa)

    2015-11-15

    Lead Titanate (PbTiO{sub 3)} is a category of the practical semiconductor metal oxides, which is widely applied in various scientific and industrial fields because of its catalytic, optical, and electrical properties. PbTiO{sub 3} nanocrystalline materials have attracted a wide attention due to their unique properties. PbTiO{sub 3} nanocrystals were investigated by X-ray diffraction (XRD) to identify the PbTiO{sub 3} nanocrystals were composed a tetragonal structure. The diameter of a single sphere was around 20 nm and the diameter reached up to 3 μm. The chemical composition of the samples and the valence states of elements were determined by X-ray photoelectron spectroscopy (XPS) in detail. - Highlights: • Single crystalline NSs of PbTiO{sub 3} fabricated by wet chemical method. • PbTiO{sub 3} NSs were uniform and continuous along the long axis. • Tetragonal perovskite structure with the diameter 20 nm and length 3 μm. • XPS spectrum was fitted with Lorentzian function respectively. • The size of the images is also 10 μm × 10 μm.

  4. Methods of forming aluminum oxynitride-comprising bodies, including methods of forming a sheet of transparent armor

    Science.gov (United States)

    Chu, Henry Shiu-Hung [Idaho Falls, ID; Lillo, Thomas Martin [Idaho Falls, ID

    2008-12-02

    The invention includes methods of forming an aluminum oxynitride-comprising body. For example, a mixture is formed which comprises A:B:C in a respective molar ratio in the range of 9:3.6-6.2:0.1-1.1, where "A" is Al.sub.2O.sub.3, "B" is AlN, and "C" is a total of one or more of B.sub.2O.sub.3, SiO.sub.2, Si--Al--O--N, and TiO.sub.2. The mixture is sintered at a temperature of at least 1,600.degree. C. at a pressure of no greater than 500 psia effective to form an aluminum oxynitride-comprising body which is at least internally transparent and has at least 99% maximum theoretical density.

  5. Heat Recovery from High Temperature Slags: A Review of Chemical Methods

    Directory of Open Access Journals (Sweden)

    Yongqi Sun

    2015-03-01

    Full Text Available Waste heat recovery from high temperature slags represents the latest potential way to remarkably reduce the energy consumption and CO2 emissions of the steel industry. The molten slags, in the temperature range of 1723–1923 K, carry large amounts of high quality energy. However, the heat recovery from slags faces several fundamental challenges, including their low thermal conductivity, inside crystallization, and discontinuous availability. During past decades, various chemical methods have been exploited and performed including methane reforming, coal and biomass gasification, and direct compositional modification and utilization of slags. These methods effectively meet the challenges mentioned before and help integrate the steel industry with other industrial sectors. During the heat recovery using chemical methods, slags can act as not only heat carriers but also as catalysts and reactants, which expands the field of utilization of slags. Fuel gas production using the waste heat accounts for the main R&D trend, through which the thermal heat in the slag could be transformed into high quality chemical energy in the fuel gas. Moreover, these chemical methods should be extended to an industrial scale to realize their commercial application, which is the only way by which the substantial energy in the slags could be extracted, i.e., amounting to 16 million tons of standard coal in China.

  6. Development of a benchtop baking method for chemically leavened crackers. II. Validation of the method

    Science.gov (United States)

    A benchtop baking method has been developed to predict the contribution of gluten functionality to overall flour performance for chemically leavened crackers. Using a diagnostic formula and procedure, dough rheology was analyzed to evaluate the extent of gluten development during mixing and machinin...

  7. ZnSe thin films by chemical bath deposition method

    Energy Technology Data Exchange (ETDEWEB)

    Lokhande, C.D.; Patil, P.S.; Tributsch, H. [Hahn-Meitner-Institute, Bereich Physikalische Chemie, Abt. CS, Glienicker Strasse-100, D-14109 Berlin (Germany); Ennaoui, A. [Hahn-Meitner-Institute, Bereich Physikalische Chemie, Abt. CG, Glienicker Strasse-100, D-14109 Berlin (Germany)

    1998-09-04

    The ZnSe thin films have been deposited onto glass substrates by the simple chemical bath deposition method using selenourea as a selenide ion source from an aqueous alkaline medium. The effect of Zn ion concentration, bath temperature and deposition time period on the quality and thickness of ZnSe films has been studied. The ZnSe films have been characterized by XRD, TEM, EDAX, TRMC (time-resolved microwave conductivity), optical absorbance and RBS techniques for their structural, compositional, electronic and optical properties. The as-deposited ZnSe films are found to be amorphous, Zn rich with optical band gap, Eg, equal to 2.9 eV

  8. Trace impurities in coal by wet chemical methods

    International Nuclear Information System (INIS)

    Pollock, E.N.

    1975-01-01

    In determining trace elements in coal by wet chemical methods, conventional atomic absorption spectroscopy (AAS) was used to determine Li, Be, V, Cr, Mn, Co, Ni, Cu, Zn, Ag, Cd, and Pb after dry ashing and acid dissolutions. A graphite furnace accessory was used for the flameless AAS determination of Bi, Se, Sn, Te, Be, Pb, As, Cd, Cr, Sb, and Ge. Mercury can be determined by flameless AAS after oxygen bomb combustion. Arsenic and antimony can be determined as their hydrides by AAS after low temperature ashing. Germanium, tin, bismuth, and tellurium can be determined as their hydrides by AAS after high temperature ashing. Selenium can be determined as its hydride by AAS after a special combustion procedure or after oxygen bomb combustion. Fluorine can be determined by specific ion analysis after oxygen bomb combustion. Boron can be determined colorimetrically. (U.S.)

  9. Studies of coupled chemical and catalytic coal conversion methods

    Energy Technology Data Exchange (ETDEWEB)

    Stock, L.M.

    1990-01-01

    This report concerns our research on base-catalyzed coal solubilization and a new approach for hydrogen addition. The work on base-catalyzed, chemical solubilization is continuing. this report is focused on the hydrogenation research. Specifically it deals with the use of arene chromium carbonyl complexes as reagents for the addition of dideuterium to coal molecules. In one phase of the work, he has established that the aromatic hydrocarbons in a representative coal liquid can be converted in very good yield to arene chromium carbonyl compounds. In a second phase of the work directly related to our objective of improved methods for catalytic hydrogenation, he has established that the aromatic constituents of the same coal liquid add dideuterium in the presence of added napththalene chromium carbonyl.

  10. Impact of physical and chemical parameters on the hydroxyapatite nanopowder synthesized by chemical precipitation method

    Science.gov (United States)

    Thu Trang Pham, Thi; Phuong Nguyen, Thu; Pham, Thi Nam; Phuong Vu, Thi; Tran, Dai Lam; Thai, Hoang; Thanh Dinh, Thi Mai

    2013-09-01

    In this paper, the synthesis of hydroxyapatite (HAp) nanopowder was studied by chemical precipitation method at different values of reaction temperature, settling time, Ca/P ratio, calcination temperature, (NH4)2HPO4 addition rate, initial concentration of Ca(NO3)2 and (NH4)2HPO4. Analysis results of properties, morphology, structure of HAp powder from infrared (IR) spectra, x-ray diffraction (XRD), energy dispersive x-ray (EDX) spectra and scanning electron microscopy (SEM) indicated that the synthesized HAp powder had cylinder crystal shape with size less than 100 nm, single-phase structure. The variation of the synthesis conditions did not affect the morphology but affected the size of HAp crystals.

  11. Development of LLNA:DAE: a new local lymph node assay that includes the elicitation phase, discriminates borderline-positive chemicals, and is useful for cross-sensitization testing.

    Science.gov (United States)

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

    2014-02-01

    We developed a new local lymph node assay (LLNA) that includes the elicitation phase termed LLNA:DAE for discrimination of borderline-positive chemicals as classified by the LLNA modified by Daicel based on ATP content (LLNA:DA) and for cross-sensitization testing. Although the LLNA:DA method could help identify skin sensitizers, some skin irritants classified as non-sensitizers by the LLNA were classified as borderline positive. In addition, the evaluation for the cross-sensitization potential between chemicals was impossible. In the LLNA:DAE procedure, test group of mice received four applications of chemicals on the dorsum of the right ear for induction and one application on the dorsum of the left ear for elicitation. Control group of mice received one chemical application on the dorsum of the left ear. We evaluated the sensitizing potential by comparing the weights of the lymph nodes from the left ears between the two groups. The results of using the LLNA:DAE method to examine 24 chemicals, which contained borderline-positive chemicals, were consistent with those from the LLNA method, except for nickel chloride (NiCl2). Two chemical pairs, 2,4-dinitrochlorobenzene (DNCB) with 2,4-dinitrofluorobenzene (DNFB) and hydroquinone (HQ) with p-benzoquinone (p-BQ), showed clear cross-sensitization with each other, while another chemical pair, DNFB with hexylcinnamic aldehyde (HCA) did not. Taken together, our results suggest that the LLNA:DAE method is useful for discriminating borderline-positive chemicals and for determining chemical cross-sensitization.

  12. Fractionation of chemical elements including the REEs and 226Ra in stream contaminated with coal-mine effluent

    International Nuclear Information System (INIS)

    Centeno, L.M.; Faure, G.; Lee, G.; Talnagi, J.

    2004-01-01

    Water draining from abandoned open-pit coal mines in southeastern Ohio typically has a low pH and high concentrations of Fe, Al and Mn, as well as of trace metals (Pb, Cu, Zn, Ni, Co, etc.) and of the rare earth elements (REEs). The cations of different elements are sorbed selectively by Fe and Al hydroxide precipitates which form with increasing pH. As a result, the trace elements are separated from each other when the hydroxide precipitates are deposited in the channel of a flowing stream. Therefore, the low-energy environment of a stream contaminated by mine effluent is a favorable site for the chemical fractionation of the REEs and of other groups of elements with similar chemical properties. The interpretation of chemical analyses of water collected along a 30-km-stretch of Rush Creek near the town of New Lexington, Perry County, Ohio, indicates that the abundances of the REEs in the water appear to change downstream when they are normalized to the REE concentrations of the mine effluent. In addition, the Ce/La ratios (and those of all REEs) in the water decrease consistently downstream. The evidence indicates that the REEs which remain in solution are enriched La and Ce because the other REEs are sorbed more efficiently. The solid Fe(OH) 3 precipitates in the channel of Rush Creek upstream of New Lexington also contain radioactive 226 Ra that was sorbed from the water. This isotope of Ra is a decay product of 238 U which occurs in the Middle Pennsylvanian (Upper Carboniferous) coal and in the associated shale of southeastern Ohio. The activity of 226 Ra of the Fe(OH) 3 precipitates increases with rising pH, but then declines farther downstream as the concentration of Ra remaining in the water decreases

  13. Implementation aspects of the Boundary Element Method including viscous and thermal losses

    DEFF Research Database (Denmark)

    Cutanda Henriquez, Vicente; Juhl, Peter Møller

    2014-01-01

    The implementation of viscous and thermal losses using the Boundary Element Method (BEM) is based on the Kirchhoff’s dispersion relation and has been tested in previous work using analytical test cases and comparison with measurements. Numerical methods that can simulate sound fields in fluids...

  14. Mechanical and chemical properties of polyvinyl alcohol modified cement mortar with silica fume used as matrix including radioactive waste

    International Nuclear Information System (INIS)

    Dakroury, A. M.

    2007-01-01

    This paper discussed the mechanical and chemical properties of polyvinyl alcohol - modified cement mortar with silica fume to assess the safety for disposal of radioactive waste. The modified cement mortars containing polyvinyl alcohol (PVA) in the presence of 10 % silica fume (SF) .The chemical reaction between polymer and cement - hydrated product were investigated by the Infrared Spectral Technology, Differential Thermal Analysis and X-ray diffraction. The leaching of 137Cs from a waste composite into a surrounding fluid has been studied .The results shown that PVA increases the strength and decreases the porosity. The increase in strength duo to the interaction of PVA with cement , may be forming some new compound that fill the pores or improve the bond between the cement . The pozzolanic reaction of the SF increases the calcium silicate hydrates in the hardening matrix composites. There is distinct change in the refinement of the pore structure in cement composites giving fewer capillary pores and more of the finer gel pores

  15. A coupling method for a cardiovascular simulation model which includes the Kalman filter.

    Science.gov (United States)

    Hasegawa, Yuki; Shimayoshi, Takao; Amano, Akira; Matsuda, Tetsuya

    2012-01-01

    Multi-scale models of the cardiovascular system provide new insight that was unavailable with in vivo and in vitro experiments. For the cardiovascular system, multi-scale simulations provide a valuable perspective in analyzing the interaction of three phenomenons occurring at different spatial scales: circulatory hemodynamics, ventricular structural dynamics, and myocardial excitation-contraction. In order to simulate these interactions, multiscale cardiovascular simulation systems couple models that simulate different phenomena. However, coupling methods require a significant amount of calculation, since a system of non-linear equations must be solved for each timestep. Therefore, we proposed a coupling method which decreases the amount of calculation by using the Kalman filter. In our method, the Kalman filter calculates approximations for the solution to the system of non-linear equations at each timestep. The approximations are then used as initial values for solving the system of non-linear equations. The proposed method decreases the number of iterations required by 94.0% compared to the conventional strong coupling method. When compared with a smoothing spline predictor, the proposed method required 49.4% fewer iterations.

  16. Turbomachine combustor nozzle including a monolithic nozzle component and method of forming the same

    Science.gov (United States)

    Stoia, Lucas John; Melton, Patrick Benedict; Johnson, Thomas Edward; Stevenson, Christian Xavier; Vanselow, John Drake; Westmoreland, James Harold

    2016-02-23

    A turbomachine combustor nozzle includes a monolithic nozzle component having a plate element and a plurality of nozzle elements. Each of the plurality of nozzle elements includes a first end extending from the plate element to a second end. The plate element and plurality of nozzle elements are formed as a unitary component. A plate member is joined with the nozzle component. The plate member includes an outer edge that defines first and second surfaces and a plurality of openings extending between the first and second surfaces. The plurality of openings are configured and disposed to register with and receive the second end of corresponding ones of the plurality of nozzle elements.

  17. General method and thermodynamic tables for computation of equilibrium composition and temperature of chemical reactions

    Science.gov (United States)

    Huff, Vearl N; Gordon, Sanford; Morrell, Virginia E

    1951-01-01

    A rapidly convergent successive approximation process is described that simultaneously determines both composition and temperature resulting from a chemical reaction. This method is suitable for use with any set of reactants over the complete range of mixture ratios as long as the products of reaction are ideal gases. An approximate treatment of limited amounts of liquids and solids is also included. This method is particularly suited to problems having a large number of products of reaction and to problems that require determination of such properties as specific heat or velocity of sound of a dissociating mixture. The method presented is applicable to a wide variety of problems that include (1) combustion at constant pressure or volume; and (2) isentropic expansion to an assigned pressure, temperature, or Mach number. Tables of thermodynamic functions needed with this method are included for 42 substances for convenience in numerical computations.

  18. Development of a quantitative safety assessment method for nuclear I and C systems including human operators

    International Nuclear Information System (INIS)

    Kim, Man Cheol

    2004-02-01

    Conventional PSA (probabilistic safety analysis) is performed in the framework of event tree analysis and fault tree analysis. In conventional PSA, I and C systems and human operators are assumed to be independent for simplicity. But, the dependency of human operators on I and C systems and the dependency of I and C systems on human operators are gradually recognized to be significant. I believe that it is time to consider the interdependency between I and C systems and human operators in the framework of PSA. But, unfortunately it seems that we do not have appropriate methods for incorporating the interdependency between I and C systems and human operators in the framework of Pasa. Conventional human reliability analysis (HRA) methods are not developed to consider the interdependecy, and the modeling of the interdependency using conventional event tree analysis and fault tree analysis seem to be, event though is does not seem to be impossible, quite complex. To incorporate the interdependency between I and C systems and human operators, we need a new method for HRA and a new method for modeling the I and C systems, man-machine interface (MMI), and human operators for quantitative safety assessment. As a new method for modeling the I and C systems, MMI and human operators, I develop a new system reliability analysis method, reliability graph with general gates (RGGG), which can substitute conventional fault tree analysis. RGGG is an intuitive and easy-to-use method for system reliability analysis, while as powerful as conventional fault tree analysis. To demonstrate the usefulness of the RGGG method, it is applied to the reliability analysis of Digital Plant Protection System (DPPS), which is the actual plant protection system of Ulchin 5 and 6 nuclear power plants located in Republic of Korea. The latest version of the fault tree for DPPS, which is developed by the Integrated Safety Assessment team in Korea Atomic Energy Research Institute (KAERI), consists of 64

  19. Method of extruding and packaging a thin sample of reactive material including forming the extrusion die

    International Nuclear Information System (INIS)

    Lewandowski, E.F.; Peterson, L.L.

    1985-01-01

    This invention teaches a method of cutting a narrow slot in an extrusion die with an electrical discharge machine by first drilling spaced holes at the ends of where the slot will be, whereby the oil can flow through the holes and slot to flush the material eroded away as the slot is being cut. The invention further teaches a method of extruding a very thin ribbon of solid highly reactive material such as lithium or sodium through the die in an inert atmosphere of nitrogen, argon or the like as in a glovebox. The invention further teaches a method of stamping out sample discs from the ribbon and of packaging each disc by sandwiching it between two aluminum sheets and cold welding the sheets together along an annular seam beyond the outer periphery of the disc. This provides a sample of high purity reactive material that can have a long shelf life

  20. Method for including detailed evaluation of daylight levels in Be06

    DEFF Research Database (Denmark)

    Petersen, Steffen

    2008-01-01

    Good daylight conditions in office buildings have become an important issue due to new European regulatory demands which include energy consumption for electrical lighting in the building energy frame. Good daylight conditions in offices are thus in increased focus as an energy conserving measure....... In order to evaluate whether a certain design is good daylight design or not building designers must perform detailed evaluation of daylight levels, including the daylight performance of dynamic solar shadings, and include these in the energy performance evaluation. However, the mandatory national...... calculation tool in Denmark (Be06) for evaluating the energy performance of buildings is currently using a simple representation of available daylight in a room and simple assumptions regarding the control of shading devices. In a case example, this is leading to an overestimation of the energy consumption...

  1. A novel method of including Landau level mixing in numerical studies of the quantum Hall effect

    International Nuclear Information System (INIS)

    Wooten, Rachel; Quinn, John; Macek, Joseph

    2013-01-01

    Landau level mixing should influence the quantum Hall effect for all except the strongest applied magnetic fields. We propose a simple method for examining the effects of Landau level mixing by incorporating multiple Landau levels into the Haldane pseudopotentials through exact numerical diagonalization. Some of the resulting pseudopotentials for the lowest and first excited Landau levels will be presented

  2. Development of Extended Ray-tracing method including diffraction, polarization and wave decay effects

    Science.gov (United States)

    Yanagihara, Kota; Kubo, Shin; Dodin, Ilya; Nakamura, Hiroaki; Tsujimura, Toru

    2017-10-01

    Geometrical Optics Ray-tracing is a reasonable numerical analytic approach for describing the Electron Cyclotron resonance Wave (ECW) in slowly varying spatially inhomogeneous plasma. It is well known that the result with this conventional method is adequate in most cases. However, in the case of Helical fusion plasma which has complicated magnetic structure, strong magnetic shear with a large scale length of density can cause a mode coupling of waves outside the last closed flux surface, and complicated absorption structure requires a strong focused wave for ECH. Since conventional Ray Equations to describe ECW do not have any terms to describe the diffraction, polarization and wave decay effects, we can not describe accurately a mode coupling of waves, strong focus waves, behavior of waves in inhomogeneous absorption region and so on. For fundamental solution of these problems, we consider the extension of the Ray-tracing method. Specific process is planned as follows. First, calculate the reference ray by conventional method, and define the local ray-base coordinate system along the reference ray. Then, calculate the evolution of the distributions of amplitude and phase on ray-base coordinate step by step. The progress of our extended method will be presented.

  3. Indication of Importance of Including Soil Microbial Characteristics into Biotope Valuation Method.

    Czech Academy of Sciences Publication Activity Database

    Trögl, J.; Pavlorková, Jana; Packová, P.; Seják, J.; Kuráň, P.; Kuráň, J.; Popelka, J.; Pacina, J.

    2016-01-01

    Roč. 8, č. 3 (2016), č. článku 253. ISSN 2071-1050 Institutional support: RVO:67985858 Keywords : biotope assessment * biotope valuation method * soil microbial communities Subject RIV: DJ - Water Pollution ; Quality Impact factor: 1.789, year: 2016

  4. Method of preparing a negative electrode including lithium alloy for use within a secondary electrochemical cell

    Science.gov (United States)

    Tomczuk, Zygmunt; Olszanski, Theodore W.; Battles, James E.

    1977-03-08

    A negative electrode that includes a lithium alloy as active material is prepared by briefly submerging a porous, electrically conductive substrate within a melt of the alloy. Prior to solidification, excess melt can be removed by vibrating or otherwise manipulating the filled substrate to expose interstitial surfaces. Electrodes of such as solid lithium-aluminum filled within a substrate of metal foam are provided.

  5. Thick electrodes including nanoparticles having electroactive materials and methods of making same

    Science.gov (United States)

    Xiao, Jie; Lu, Dongping; Liu, Jun; Zhang, Jiguang; Graff, Gordon L.

    2017-02-21

    Electrodes having nanostructure and/or utilizing nanoparticles of active materials and having high mass loadings of the active materials can be made to be physically robust and free of cracks and pinholes. The electrodes include nanoparticles having electroactive material, which nanoparticles are aggregated with carbon into larger secondary particles. The secondary particles can be bound with a binder to form the electrode.

  6. An integrated mathematical model for chemical oxygen demand (COD) removal in moving bed biofilm reactors (MBBR) including predation and hydrolysis.

    Science.gov (United States)

    Revilla, Marta; Galán, Berta; Viguri, Javier R

    2016-07-01

    An integrated mathematical model is proposed for modelling a moving bed biofilm reactor (MBBR) for removal of chemical oxygen demand (COD) under aerobic conditions. The composite model combines the following: (i) a one-dimensional biofilm model, (ii) a bulk liquid model, and (iii) biological processes in the bulk liquid and biofilm considering the interactions among autotrophic, heterotrophic and predator microorganisms. Depending on the values for the soluble biodegradable COD loading rate (SCLR), the model takes into account a) the hydrolysis of slowly biodegradable compounds in the bulk liquid, and b) the growth of predator microorganisms in the bulk liquid and in the biofilm. The integration of the model and the SCLR allows a general description of the behaviour of COD removal by the MBBR under various conditions. The model is applied for two in-series MBBR wastewater plant from an integrated cellulose and viscose production and accurately describes the experimental concentrations of COD, total suspended solids (TSS), nitrogen and phosphorous obtained during 14 months working at different SCLRs and nutrient dosages. The representation of the microorganism group distribution in the biofilm and in the bulk liquid allow for verification of the presence of predator microorganisms in the second reactor under some operational conditions. Copyright © 2016 Elsevier Ltd. All rights reserved.

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

    Science.gov (United States)

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

    2017-04-01

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

  8. Method for pulse control in a laser including a stimulated brillouin scattering mirror system

    Science.gov (United States)

    Dane, C. Brent; Hackel, Lloyd; Harris, Fritz B.

    2007-10-23

    A laser system, such as a master oscillator/power amplifier system, comprises a gain medium and a stimulated Brillouin scattering SBS mirror system. The SBS mirror system includes an in situ filtered SBS medium that comprises a compound having a small negative non-linear index of refraction, such as a perfluoro compound. An SBS relay telescope having a telescope focal point includes a baffle at the telescope focal point which blocks off angle beams. A beam splitter is placed between the SBS mirror system and the SBS relay telescope, directing a fraction of the beam to an alternate beam path for an alignment fiducial. The SBS mirror system has a collimated SBS cell and a focused SBS cell. An adjustable attenuator is placed between the collimated SBS cell and the focused SBS cell, by which pulse width of the reflected beam can be adjusted.

  9. Physical-chemical property based sequence motifs and methods regarding same

    Science.gov (United States)

    Braun, Werner [Friendswood, TX; Mathura, Venkatarajan S [Sarasota, FL; Schein, Catherine H [Friendswood, TX

    2008-09-09

    A data analysis system, program, and/or method, e.g., a data mining/data exploration method, using physical-chemical property motifs. For example, a sequence database may be searched for identifying segments thereof having physical-chemical properties similar to the physical-chemical property motifs.

  10. Increased Surface Roughness in Polydimethylsiloxane Films by Physical and Chemical Methods

    Directory of Open Access Journals (Sweden)

    Jorge Nicolás Cabrera

    2017-08-01

    Full Text Available Two methods, the first physical and the other chemical, were investigated to modify the surface roughness of polydimethylsiloxane (PDMS films. The physical method consisted of dispersing multi-walled carbon nanotubes (MWCNTs and magnetic cobalt ferrites (CoFe2O4 prior to thermal cross-linking, and curing the composite system in the presence of a uniform magnetic field H. The chemical method was based on exposing the films to bromine vapours and then UV-irradiating. The characterizing techniques included scanning electron microscopy (SEM, energy-dispersive spectroscopy (EDS, Fourier transform infrared (FTIR spectroscopy, optical microscopy, atomic force microscopy (AFM and magnetic force microscopy (MFM. The surface roughness was quantitatively analyzed by AFM. In the physical method, the random dispersion of MWCNTs (1% w/w and magnetic nanoparticles (2% w/w generated a roughness increase of about 200% (with respect to PDMS films without any treatment, but that change was 400% for films cured in the presence of H perpendicular to the surface. SEM, AFM and MFM showed that the magnetic particles always remained attached to the carbon nanotubes, and the effect on the roughness was interpreted as being due to a rupture of dispersion randomness and a possible induction of structuring in the direction of H. In the chemical method, the increase in roughness was even greater (1000%. Wells were generated with surface areas that were close to 100 μm2 and depths of up to 500 nm. The observations of AFM images and FTIR spectra were in agreement with the hypothesis of etching by Br radicals generated by UV on the polymer chains. Both methods induced important changes in the surface roughness (the chemical method generated the greatest changes due to the formation of surface wells, which are of great importance in superficial technological processes.

  11. Synchronization and Arrest of the Budding Yeast Cell Cycle Using Chemical and Genetic Methods.

    Science.gov (United States)

    Rosebrock, Adam P

    2017-01-03

    The cell cycle of budding yeast can be arrested at specific positions by different genetic and chemical methods. These arrests enable study of cell cycle phase-specific phenotypes that would be missed during examination of asynchronous cultures. Some methods for arrest are reversible, with kinetics that enable release of cells back into a synchronous cycling state. Benefits of chemical and genetic methods include scalability across a large range of culture sizes from a few milliliters to many liters, ease of execution, the absence of specific equipment requirements, and synchronization and release of the entire culture. Of note, cell growth and division are decoupled during arrest and block-release experiments. Cells will continue transcription, translation, and accumulation of protein while arrested. If allowed to reenter the cell cycle, cells will do so as a population of mixed, larger-than-normal cells. Despite this important caveat, many aspects of budding yeast physiology are accessible using these simple chemical and genetic tools. Described here are methods for the block and release of cells in G 1 phase and at the M/G 1 transition using α-factor mating pheromone and the temperature-sensitive cdc15-2 allele, respectively, in addition to methods for arresting the cell cycle in early S phase and at G 2 /M by using hydroxyurea and nocodazole, respectively. © 2017 Cold Spring Harbor Laboratory Press.

  12. Impact of Including Authentic Inquiry Experiences in Methods Courses for Pre-Service Secondary Teachers

    Science.gov (United States)

    Slater, T. F.; Elfring, L.; Novodvorsky, I.; Talanquer, V.; Quintenz, J.

    2007-12-01

    Science education reform documents universally call for students to have authentic and meaningful experiences using real data in the context of their science education. The underlying philosophical position is that students analyzing data can have experiences that mimic actual research. In short, research experiences that reflect the scientific spirit of inquiry potentially can: prepare students to address real world complex problems; develop students' ability to use scientific methods; prepare students to critically evaluate the validity of data or evidence and of the consequent interpretations or conclusions; teach quantitative skills, technical methods, and scientific concepts; increase verbal, written, and graphical communication skills; and train students in the values and ethics of working with scientific data. However, it is unclear what the broader pre-service teacher preparation community is doing in preparing future teachers to promote, manage, and successful facilitate their own students in conducting authentic scientific inquiry. Surveys of undergraduates in secondary science education programs suggests that students have had almost no experiences themselves in conducting open scientific inquiry where they develop researchable questions, design strategies to pursue evidence, and communicate data-based conclusions. In response, the College of Science Teacher Preparation Program at the University of Arizona requires all students enrolled in its various science teaching methods courses to complete an open inquiry research project and defend their findings at a specially designed inquiry science mini-conference at the end of the term. End-of-term surveys show that students enjoy their research experience and believe that this experience enhances their ability to facilitate their own future students in conducting open inquiry.

  13. Distinct Adsorption Configurations and Self-Assembly Characteristics of Fibrinogen on Chemically Uniform and Alternating Surfaces including Block Copolymer Nanodomains

    Science.gov (United States)

    2015-01-01

    Understanding protein–surface interactions is crucial to solid-state biomedical applications whose functionality is directly correlated with the precise control of the adsorption configuration, surface packing, loading density, and bioactivity of protein molecules. Because of the small dimensions and highly amphiphilic nature of proteins, investigation of protein adsorption performed on nanoscale topology can shed light on subprotein-level interaction preferences. In this study, we examine the adsorption and assembly behavior of a highly elongated protein, fibrinogen, on both chemically uniform (as-is and buffered HF-treated SiO2/Si, and homopolymers of polystyrene and poly(methyl methacrylate)) and varying (polystyrene-block-poly(methyl methacrylate)) surfaces. By focusing on high-resolution imaging of individual protein molecules whose configurations are influenced by protein–surface rather than protein–protein interactions, fibrinogen conformations characteristic to each surface are identified and statistically analyzed for structural similarities/differences in key protein domains. By exploiting block copolymer nanodomains whose repeat distance is commensurate with the length of the individual protein, we determine that fibrinogen exhibits a more neutral tendency for interaction with both polystyrene and poly(methyl methacrylate) blocks relative to the case of common globular proteins. Factors affecting fibrinogen–polymer interactions are discussed in terms of hydrophobic and electrostatic interactions. In addition, assembly and packing attributes of fibrinogen are determined at different loading conditions. Primary orientations of fibrinogen and its rearrangements with respect to the underlying diblock nanodomains associated with different surface coverage are explained by pertinent protein interaction mechanisms. On the basis of two-dimensional stacking behavior, a protein assembly model is proposed for the formation of an extended fibrinogen network

  14. Comparison of some biased estimation methods (including ordinary subset regression) in the linear model

    Science.gov (United States)

    Sidik, S. M.

    1975-01-01

    Ridge, Marquardt's generalized inverse, shrunken, and principal components estimators are discussed in terms of the objectives of point estimation of parameters, estimation of the predictive regression function, and hypothesis testing. It is found that as the normal equations approach singularity, more consideration must be given to estimable functions of the parameters as opposed to estimation of the full parameter vector; that biased estimators all introduce constraints on the parameter space; that adoption of mean squared error as a criterion of goodness should be independent of the degree of singularity; and that ordinary least-squares subset regression is the best overall method.

  15. Use of the potentiometric titration method to investigate heterogeneous systems including phosphorylated complexones

    International Nuclear Information System (INIS)

    Tereshin, G.S.; Kharitonova, L.K.; Kuznetsova, O.B.

    1979-01-01

    Heterogeneous systems Y(NO 3 ) 3 (YCl 3 )-Hsub(n)L-KNO 3 (KCl)-H 2 O are investigated by potentiometric titration (with coulomb-meter generation of oH - ions). Hsub(n)L is one of the following: oxyethylidendiphosphonic; aminobenzilidendiphosphonic; glycine-bis-methyl-phosphonic; nitrilotrimethylphosphonic (H 6 L) and ethylenediaminetetramethylphosphonic acids. The range of the exsistence of YHsub(nL3)LxyH 2 O has been determined. The possibility of using potentiometric titration for investigating heterogeneous systems is demonstrated by the stUdy of the system Y(NO 3 ) 3 -H 6 L-KOH-H 2 o by the method of residual concentration. The two methods have shown that at pH 3 LxyH 2 O; at pH=6, KYH 2 Lxy'H 2 O, and at pH=7, K 2 YHLxy''H 2 O. The complete solubility products of nitrilotrimethylphosphonates are evaluated

  16. A convolution method for predicting mean treatment dose including organ motion at imaging

    International Nuclear Information System (INIS)

    Booth, J.T.; Zavgorodni, S.F.; Royal Adelaide Hospital, SA

    2000-01-01

    Full text: The random treatment delivery errors (organ motion and set-up error) can be incorporated into the treatment planning software using a convolution method. Mean treatment dose is computed as the convolution of a static dose distribution with a variation kernel. Typically this variation kernel is Gaussian with variance equal to the sum of the organ motion and set-up error variances. We propose a novel variation kernel for the convolution technique that additionally considers the position of the mobile organ in the planning CT image. The systematic error of organ position in the planning CT image can be considered random for each patient over a population. Thus the variance of the variation kernel will equal the sum of treatment delivery variance and organ motion variance at planning for the population of treatments. The kernel is extended to deal with multiple pre-treatment CT scans to improve tumour localisation for planning. Mean treatment doses calculated with the convolution technique are compared to benchmark Monte Carlo (MC) computations. Calculations of mean treatment dose using the convolution technique agreed with MC results for all cases to better than ± 1 Gy in the planning treatment volume for a prescribed 60 Gy treatment. Convolution provides a quick method of incorporating random organ motion (captured in the planning CT image and during treatment delivery) and random set-up errors directly into the dose distribution. Copyright (2000) Australasian College of Physical Scientists and Engineers in Medicine

  17. System and method for detecting components of a mixture including a valving scheme for competition assays

    Energy Technology Data Exchange (ETDEWEB)

    Koh, Chung-Yan; Piccini, Matthew E.; Singh, Anup K.

    2017-09-19

    Examples are described including measurement systems for conducting competition assays. A first chamber of an assay device may be loaded with a sample containing a target antigen. The target antigen in the sample may be allowed to bind to antibody-coated beads in the first chamber. A control layer separating the first chamber from a second chamber may then be opened to allow a labeling agent loaded in a first portion of the second chamber to bind to any unoccupied sites on the antibodies. A centrifugal force may then be applied to transport the beads through a density media to a detection region for measurement by a detection unit.

  18. System and method for detecting components of a mixture including a valving scheme for competition assays

    Science.gov (United States)

    Koh, Chung-Yan; Piccini, Matthew E.; Singh, Anup K.

    2017-07-11

    Examples are described including measurement systems for conducting competition assays. A first chamber of an assay device may be loaded with a sample containing a target antigen. The target antigen in the sample may be allowed to bind to antibody-coated beads in the first chamber. A control layer separating the first chamber from a second chamber may then be opened to allow a labeling agent loaded in a first portion of the second chamber to bind to any unoccupied sites on the antibodies. A centrifugal force may then be applied to transport the beads through a density media to a detection region for measurement by a detection unit.

  19. Electromagnetic Radiation : Variational Methods, Waveguides and Accelerators Including seminal papers of Julian Schwinger

    CERN Document Server

    Milton, Kimball A

    2006-01-01

    This is a graduate level textbook on the theory of electromagnetic radiation and its application to waveguides, transmission lines, accelerator physics and synchrotron radiation. It has grown out of lectures and manuscripts by Julian Schwinger prepared during the war at MIT's Radiation Laboratory, updated with material developed by Schwinger at UCLA in the 1970s and 1980s, and by Milton at the University of Oklahoma since 1994. The book includes a great number of straightforward and challenging exercises and problems. It is addressed to students in physics, electrical engineering, and applied mathematics seeking a thorough introduction to electromagnetism with emphasis on radiation theory and its applications.

  20. Decoding Facial Esthetics to Recreate an Esthetic Hairline: A Method Which Includes Forehead Curvature.

    Science.gov (United States)

    Garg, Anil K; Garg, Seema

    2017-01-01

    The evidence suggests that our perception of physical beauty is based on how closely the features of one's face reflect phi (the golden ratio) in their proportions. By that extension, it must certainly be possible to use a mathematical parameter to design an anterior hairline in all faces. To establish a user-friendly method to design an anterior hairline in cases of male pattern alopecia. We need a flexible measuring tape and skin marker. A reference point A (glabella) is taken in between eyebrows. Mark point E, near the lateral canthus, 8 cm horizontal on either side from the central point A. A mid-frontal point (point B) is marked 8 cm from point A on the forehead in a mid-vertical plane. The frontotemporal points (C and C') are marked on the frontotemporal area, 8 cm in a horizontal plane from point B and 8 cm in a vertical plane from point E. The temporal peak points (D and D') are marked on the line joining the frontotemporal point C to the lateral canthus point E, slightly more than halfway toward lateral canthus, usually 5 cm from the frontotemporal point C. This line makes an anterior border of the temporal triangle. We have conducted a study with 431 cases of male pattern alopecia. The average distance of the mid-frontal point from glabella was 7.9 cm. The patient satisfaction reported was 94.7%. Our method gives a skeletal frame of the anterior hairline with minimal criteria, with no need of visual imagination and experience of the surgeon. It automatically takes care of the curvature of the forehead and is easy to use for a novice surgeon.

  1. In Silico Prediction of Chemical Toxicity for Drug Design Using Machine Learning Methods and Structural Alerts

    Science.gov (United States)

    Yang, Hongbin; Sun, Lixia; Li, Weihua; Liu, Guixia; Tang, Yun

    2018-02-01

    For a drug, safety is always the most important issue, including a variety of toxicities and adverse drug effects, which should be evaluated in preclinical and clinical trial phases. This review article at first simply introduced the computational methods used in prediction of chemical toxicity for drug design, including machine learning methods and structural alerts. Machine learning methods have been widely applied in qualitative classification and quantitative regression studies, while structural alerts can be regarded as a complementary tool for lead optimization. The emphasis of this article was put on the recent progress of predictive models built for various toxicities. Available databases and web servers were also provided. Though the methods and models are very helpful for drug design, there are still some challenges and limitations to be improved for drug safety assessment in the future.

  2. In Silico Prediction of Chemical Toxicity for Drug Design Using Machine Learning Methods and Structural Alerts

    Directory of Open Access Journals (Sweden)

    Hongbin Yang

    2018-02-01

    Full Text Available During drug development, safety is always the most important issue, including a variety of toxicities and adverse drug effects, which should be evaluated in preclinical and clinical trial phases. This review article at first simply introduced the computational methods used in prediction of chemical toxicity for drug design, including machine learning methods and structural alerts. Machine learning methods have been widely applied in qualitative classification and quantitative regression studies, while structural alerts can be regarded as a complementary tool for lead optimization. The emphasis of this article was put on the recent progress of predictive models built for various toxicities. Available databases and web servers were also provided. Though the methods and models are very helpful for drug design, there are still some challenges and limitations to be improved for drug safety assessment in the future.

  3. In Silico Prediction of Chemical Toxicity for Drug Design Using Machine Learning Methods and Structural Alerts.

    Science.gov (United States)

    Yang, Hongbin; Sun, Lixia; Li, Weihua; Liu, Guixia; Tang, Yun

    2018-01-01

    During drug development, safety is always the most important issue, including a variety of toxicities and adverse drug effects, which should be evaluated in preclinical and clinical trial phases. This review article at first simply introduced the computational methods used in prediction of chemical toxicity for drug design, including machine learning methods and structural alerts. Machine learning methods have been widely applied in qualitative classification and quantitative regression studies, while structural alerts can be regarded as a complementary tool for lead optimization. The emphasis of this article was put on the recent progress of predictive models built for various toxicities. Available databases and web servers were also provided. Though the methods and models are very helpful for drug design, there are still some challenges and limitations to be improved for drug safety assessment in the future.

  4. Extension of a hybrid particle-continuum method for a mixture of chemical species

    Science.gov (United States)

    Verhoff, Ashley M.; Boyd, Iain D.

    2012-11-01

    Due to the physical accuracy and numerical efficiency achieved by analyzing transitional, hypersonic flow fields with hybrid particle-continuum methods, this paper describes a Modular Particle-Continuum (MPC) method and its extension to include multiple chemical species. Considerations that are specific to a hybrid approach for simulating gas mixtures are addressed, including a discussion of the Chapman-Enskog velocity distribution function (VDF) for near-equilibrium flows, and consistent viscosity models for the individual CFD and DSMC modules of the MPC method. Representative results for a hypersonic blunt-body flow are then presented, where the flow field properties, surface properties, and computational performance are compared for simulations employing full CFD, full DSMC, and the MPC method.

  5. Multi trace element analysis of dry biological materials by neutron activation analysis including a chemical group separation

    International Nuclear Information System (INIS)

    Weers, C.A.

    1980-07-01

    Multi-element analysis of dry biological material by neutron activation analysis has to include radiochemical separation. The evaporation process is described in terms of the half-volume. The pretreatment of the samples and the development of the destruction-evaporation apparatus are described. The successive adsorption steps with active charcoal, Al 2 O 3 and coprecipitation with Fe(OH) 3 are described. Results obtained for standard reference materials are summarized. (G.T.H.)

  6. A method for making an inert porous electrode for a chemical current source

    Energy Technology Data Exchange (ETDEWEB)

    Ksenzhek, O.S.; Litvinova, V.I.; Martynenko, T.L.; Raykhelson, L.B.; Shembel, Ye.M.; Sokolov, L.A.

    1983-01-01

    A method is proposed for making an inert, porous electrode for chemical current sources (KhIT) with a nonaqueous electrolyte on the basis of aprotonic solvents and an active cathode substance which is dissolved in the electrolyte. The method includes preparing an electrode mass from the starting material and subsequent formation of the electrode. To increase the energy capacity, after formation, the electrode is subjected to electrochemical anode polarization to potentials which correspond to the potential of electrochemical breakdown of the background electrolyte.

  7. Consensus for nonmelanoma skin cancer treatment: basal cell carcinoma, including a cost analysis of treatment methods.

    Science.gov (United States)

    Kauvar, Arielle N B; Cronin, Terrence; Roenigk, Randall; Hruza, George; Bennett, Richard

    2015-05-01

    Basal cell carcinoma (BCC) is the most common cancer in the US population affecting approximately 2.8 million people per year. Basal cell carcinomas are usually slow-growing and rarely metastasize, but they do cause localized tissue destruction, compromised function, and cosmetic disfigurement. To provide clinicians with guidelines for the management of BCC based on evidence from a comprehensive literature review, and consensus among the authors. An extensive review of the medical literature was conducted to evaluate the optimal treatment methods for cutaneous BCC, taking into consideration cure rates, recurrence rates, aesthetic and functional outcomes, and cost-effectiveness of the procedures. Surgical approaches provide the best outcomes for BCCs. Mohs micrographic surgery provides the highest cure rates while maximizing tissue preservation, maintenance of function, and cosmesis. Mohs micrographic surgery is an efficient and cost-effective procedure and remains the treatment of choice for high-risk BCCs and for those in cosmetically sensitive locations. Nonsurgical modalities may be used for low-risk BCCs when surgery is contraindicated or impractical, but the cure rates are lower.

  8. Research on Chemical Composition and Biological Properties Including Antiquorum Sensing Activity of Angelica pancicii Vandas Aerial Parts and Roots.

    Science.gov (United States)

    Mileski, Ksenija S; Trifunović, Snežana S; Ćirić, Ana D; Šakić, Željana M; Ristić, Mihailo S; Todorović, Nina M; Matevski, Vlado S; Marin, Petar D; Tešević, Vele V; Džamić, Ana M

    2017-12-20

    The essential oil, different extracts, and isolated compounds of Angelica pancicii Vandas (Apiaceae) were investigated for the first time. The GC-FID and GC-MS analyses revealed sesquiterpenoids as the main constituents of A. pancicii essential oil of aerial parts with bornyl acetate (8.08%), n-octanol (5.82%), kessane (4.26%), and β-selinene (4.26%) as the main constituents. Analysis of methanol extracts, using an HPLC-DAD/ESI-ToF-MS system, showed a total of 52 compounds in the aerial parts and 53 in the roots, indicating coumarins as the main constituents. In addition, new chromone (1) and six known furanocoumarins (2-7) were isolated from the roots and structurally elucidated by combined spectroscopic methods. The aerial part extracts exhibited higher polyphenolic contents and antioxidant activity evaluated by three radical scavenging assays. Using a microwell dilution method, the strongest antibacterial activity profiles were determined for ethanol and methanol root extracts (minimum bactericidal concentrations (MBCs) = 0.25-3.00 mg/mL), which were comparable to the activity of streptomycin (MBCs = 0.34-1.24 mg/mL), while the strongest antibacterial compound of A. pancicii was oxypeucedanin hydrate (MBCs = 0.50-8.00 mg/mL). Antifungal potential was in moderate extent, and the highest activity was obtained for root methanol extract (minimum fungicidal concentrations (MFCs) = 4.00-14.00 mg/mL). Tested sub-minimum inhibitory concentrations (subMICs) of the extracts and isolated compounds inhibited selected Pseudomonas aeruginosa PAO1 virulence determinants. The most reduced growth of P. aeruginosa colony was in the presence of isolated oxypeucedanin. Ethanol (17.36-46.98%) and methanol (34.54-52.43%) root extracts showed higher anti-biofilm activity compared to streptomycin (49.40-88.36%) and ampicillin (56.46-92.16%).

  9. Evaluation of a chemical risk assessment method of South Korea for chemicals classified as carcinogenic, mutagenic or reprotoxic (CMR).

    Science.gov (United States)

    Kim, Min-Uk; Byeon, Sang-Hoon

    2017-12-12

    Chemicals were used in various fields by the development of industry and science and technology. The Chemical Hazard Risk Management (CHARM) was developed to assess the risk of chemicals in South Korea. In this study, we were to evaluate the CHARM model developed for the effective management of workplace chemicals. We used 59 carcinogenic, mutagenic or reprotoxic (CMR) materials, which are both the work environment measurement result and the usage information among the manufacturer data. The CHARM model determines the risk to human health using the exposure level (based on working environment measurements or a combination of the quantity used and chemical physical properties (e.g., fugacity and volatility)), hazard (using occupational exposure limit (OEL) or Risk phrases (R-phrases)/Hazard statements (H-statements) from the Material Safety Data Sheet (MSDS)). The risk level was lower when using the results of the work environment measurement than when applying the chemical quantity and physical properties in the exposure level evaluation method. It was evaluated as grade 4 for the CMR material in the hazard class determination. The risk assessment method by R-phrases was evaluated more conservatively than the risk assessment method by OEL. And the risk assessment method by H-statements was evaluated more conservatively than the risk assessment method by R-phrases. The CHARM model was gradually conservatively assessed as it proceeded in the next step without quantitative information for individual workplaces. The CHARM is expected to help identify the risk if the hazards and exposure levels of chemicals were identified in individual workplaces. For CMR substances, although CHARM is highly evaluated for hazards, the risk is assessed to be low if exposure levels are assessed low. When evaluating the risk of highly hazardous chemicals such as CMR substances, we believe the model should be adapted to be more conservative and classify these as higher risk. This work is

  10. Wavelet-based Adaptive Mesh Refinement Method for Global Atmospheric Chemical Transport Modeling

    Science.gov (United States)

    Rastigejev, Y.

    2011-12-01

    Numerical modeling of global atmospheric chemical transport presents enormous computational difficulties, associated with simulating a wide range of time and spatial scales. The described difficulties are exacerbated by the fact that hundreds of chemical species and thousands of chemical reactions typically are used for chemical kinetic mechanism description. These computational requirements very often forces researches to use relatively crude quasi-uniform numerical grids with inadequate spatial resolution that introduces significant numerical diffusion into the system. It was shown that this spurious diffusion significantly distorts the pollutant mixing and transport dynamics for typically used grid resolution. The described numerical difficulties have to be systematically addressed considering that the demand for fast, high-resolution chemical transport models will be exacerbated over the next decade by the need to interpret satellite observations of tropospheric ozone and related species. In this study we offer dynamically adaptive multilevel Wavelet-based Adaptive Mesh Refinement (WAMR) method for numerical modeling of atmospheric chemical evolution equations. The adaptive mesh refinement is performed by adding and removing finer levels of resolution in the locations of fine scale development and in the locations of smooth solution behavior accordingly. The algorithm is based on the mathematically well established wavelet theory. This allows us to provide error estimates of the solution that are used in conjunction with an appropriate threshold criteria to adapt the non-uniform grid. Other essential features of the numerical algorithm include: an efficient wavelet spatial discretization that allows to minimize the number of degrees of freedom for a prescribed accuracy, a fast algorithm for computing wavelet amplitudes, and efficient and accurate derivative approximations on an irregular grid. The method has been tested for a variety of benchmark problems

  11. Environmental Chemicals in Urine and Blood: Improving Methods for Creatinine and Lipid Adjustment

    Science.gov (United States)

    O’Brien, Katie M.; Upson, Kristen; Cook, Nancy R.; Weinberg, Clarice R.

    2015-01-01

    Background Investigators measuring exposure biomarkers in urine typically adjust for creatinine to account for dilution-dependent sample variation in urine concentrations. Similarly, it is standard to adjust for serum lipids when measuring lipophilic chemicals in serum. However, there is controversy regarding the best approach, and existing methods may not effectively correct for measurement error. Objectives We compared adjustment methods, including novel approaches, using simulated case–control data. Methods Using a directed acyclic graph framework, we defined six causal scenarios for epidemiologic studies of environmental chemicals measured in urine or serum. The scenarios include variables known to influence creatinine (e.g., age and hydration) or serum lipid levels (e.g., body mass index and recent fat intake). Over a range of true effect sizes, we analyzed each scenario using seven adjustment approaches and estimated the corresponding bias and confidence interval coverage across 1,000 simulated studies. Results For urinary biomarker measurements, our novel method, which incorporates both covariate-adjusted standardization and the inclusion of creatinine as a covariate in the regression model, had low bias and possessed 95% confidence interval coverage of nearly 95% for most simulated scenarios. For serum biomarker measurements, a similar approach involving standardization plus serum lipid level adjustment generally performed well. Conclusions To control measurement error bias caused by variations in serum lipids or by urinary diluteness, we recommend improved methods for standardizing exposure concentrations across individuals. Citation O’Brien KM, Upson K, Cook NR, Weinberg CR. 2016. Environmental chemicals in urine and blood: improving methods for creatinine and lipid adjustment. Environ Health Perspect 124:220–227; http://dx.doi.org/10.1289/ehp.1509693 PMID:26219104

  12. Method of manipulating the chemical properties of water to improve the effectiveness of a desired process

    Science.gov (United States)

    Hawthorne, Steven B.; Miller, David J.; Lagadec, Arnaud Jean-Marie; Hammond, Peter James; Clifford, Anthony Alan

    2002-01-01

    The method of the present invention is adapted to manipulate the chemical properties of water in order to improve the effectiveness of a desired process. The method involves heating the water in the vessel to subcritical temperatures between 100.degree. to 374.degree. C. while maintaining sufficient pressure to the water to maintain the water in the liquid state. Various physiochemical properties of the water can be manipulated including polarity, solute solubility, surface tension, viscosity, and the disassociation constant. The method of the present invention has various uses including extracting organics from solids and semisolids such as soil, selectively extracting desired organics from liquids, selectively separating organics using sorbent phases, enhancing reactions by controlling the disassociation constant of water, cleaning waste water, removing organics from water using activated carbon or other suitable sorbents, and degrading various compounds.

  13. The contact-temperature ignition (CTI) criteria for propagating chemical reactions including the effect of moisture and application to Hanford waste

    International Nuclear Information System (INIS)

    Cash, R.J.

    1995-01-01

    To assure the continued absence of uncontrolled condensed-phase chemical reactions in connection with the Hanford waste materials, efforts have been underway including both theoretical and experimental investigations to clarify the requirements for such reactions. This document defines the differences and requirements for homogeneous runaway and propagating chemical reactions incuding a discussion of general contact-temperature ignition (CTI) condition for propagating reactions that include the effect of moisture. The CTI condition implies that the contact temperature or interface temperature between reacted and unreacted materials must exceed the ignition temperature and is compared to experimental data including both synthetic ferrocyanide and surrogate organic materials. In all cases, the occurrences of ignition accompanied by self-propagating reactions are consistent with the theoretical anticipations of the CTI condition

  14. Additivity methods for prediction of thermochemical properties. The Laidler method revisited. 2. Hydrocarbons including substituted cyclic compounds

    International Nuclear Information System (INIS)

    Santos, Rui C.; Leal, Joao P.; Martinho Simoes, Jose A.

    2009-01-01

    A revised parameterization of the extended Laidler method for predicting standard molar enthalpies of atomization and standard molar enthalpies of formation at T = 298.15 K for several families of hydrocarbons (alkanes, alkenes, alkynes, polyenes, poly-ynes, cycloalkanes, substituted cycloalkanes, cycloalkenes, substituted cycloalkenes, benzene derivatives, and bi and polyphenyls) is presented. Data for a total of 265 gas-phase and 242 liquid-phase compounds were used for the calculation of the parameters. Comparison of the experimental values with those obtained using the additive scheme led to an average absolute difference of 0.73 kJ . mol -1 for the gas-phase standard molar enthalpy of formation and 0.79 kJ . mol -1 for the liquid-phase standard molar enthalpy of formation. The database used to establish the parameters was carefully reviewed by using, whenever possible, the original publications. A worksheet to simplify the calculation of standard molar enthalpies of formation and standard molar enthalpies of atomization at T = 298.15 K based on the extended Laidler parameters defined in this paper is provided as supplementary material.

  15. Methods and tools for sustainable chemical process design

    DEFF Research Database (Denmark)

    Loureiro da Costa Lira Gargalo, Carina; Chairakwongsa, Siwanat; Quaglia, Alberto

    2015-01-01

    As the pressure on chemical and biochemical processes to achieve a more sustainable performance increases, the need to define a systematic and holistic way to accomplish this is becoming more urgent. In this chapter, a multilevel computer-aided framework for systematic design of more sustainable...

  16. Current methods in risk assessment of genotoxic chemicals.

    Science.gov (United States)

    Cartus, Alexander; Schrenk, Dieter

    2017-08-01

    Chemical contaminants and residues are undesired chemicals occurring in consumer products such as food and drugs, at the workplace and in the environment, i.e. in air, soil and water. These compounds can be detected even at very low concentrations and lead frequently to considerable concerns among consumers and in the media. Thus it is a major challenge for modern toxicology to provide transparent and versatile tools for the risk assessment of such compounds in particular with respect to human health. Well-known examples of toxic contaminants are dioxins or mercury (in the environment), mycotoxins (from infections by molds) or acrylamide (from thermal treatment of food). The process of toxicological risk assessment of such chemicals is based on i) the knowledge of their contents in food, air, water etc., ii) the routes and extent of exposure of humans, iii) the toxicological properties of the compound, and, iv) its mode(s) of action. In this process quantitative dose-response relationships, usually in experimental animals, are of outstanding importance. For a successful risk assessment, in particular of genotoxic chemicals, several conditions and models such as the Margin of Exposure (MoE) approach or the Threshold of Toxicological Concern (TTC) concept exist, which will be discussed. Copyright © 2016 Elsevier Ltd. All rights reserved.

  17. Effects of different chemical materials and cultural methods on ...

    African Journals Online (AJOL)

    reading 6

    2011-10-27

    Oct 27, 2011 ... which accounts for 53% of wheat production in China and about 15% of the total ... environment as it is mainly made from chemical mate- rials. ... yield and yield components in harvest in both years were deter- mined. The data were subjected to analyses of variance (ANOVA) ..... Long-term stability of.

  18. Using deuterated PAH amendments to validate chemical extraction methods to predict PAH bioavailability in soils

    International Nuclear Information System (INIS)

    Gomez-Eyles, Jose L.; Collins, Chris D.; Hodson, Mark E.

    2011-01-01

    Validating chemical methods to predict bioavailable fractions of polycyclic aromatic hydrocarbons (PAHs) by comparison with accumulation bioassays is problematic. Concentrations accumulated in soil organisms not only depend on the bioavailable fraction but also on contaminant properties. A historically contaminated soil was freshly spiked with deuterated PAHs (dPAHs). dPAHs have a similar fate to their respective undeuterated analogues, so chemical methods that give good indications of bioavailability should extract the fresh more readily available dPAHs and historic more recalcitrant PAHs in similar proportions to those in which they are accumulated in the tissues of test organisms. Cyclodextrin and butanol extractions predicted the bioavailable fraction for earthworms (Eisenia fetida) and plants (Lolium multiflorum) better than the exhaustive extraction. The PAHs accumulated by earthworms had a larger dPAH:PAH ratio than that predicted by chemical methods. The isotope ratio method described here provides an effective way of evaluating other chemical methods to predict bioavailability. - Research highlights: → Isotope ratios can be used to evaluate chemical methods to predict bioavailability. → Chemical methods predicted bioavailability better than exhaustive extractions. → Bioavailability to earthworms was still far from that predicted by chemical methods. - A novel method using isotope ratios to assess the ability of chemical methods to predict PAH bioavailability to soil biota.

  19. Using deuterated PAH amendments to validate chemical extraction methods to predict PAH bioavailability in soils

    Energy Technology Data Exchange (ETDEWEB)

    Gomez-Eyles, Jose L., E-mail: j.l.gomezeyles@reading.ac.uk [University of Reading, School of Human and Environmental Sciences, Soil Research Centre, Reading, RG6 6DW Berkshire (United Kingdom); Collins, Chris D.; Hodson, Mark E. [University of Reading, School of Human and Environmental Sciences, Soil Research Centre, Reading, RG6 6DW Berkshire (United Kingdom)

    2011-04-15

    Validating chemical methods to predict bioavailable fractions of polycyclic aromatic hydrocarbons (PAHs) by comparison with accumulation bioassays is problematic. Concentrations accumulated in soil organisms not only depend on the bioavailable fraction but also on contaminant properties. A historically contaminated soil was freshly spiked with deuterated PAHs (dPAHs). dPAHs have a similar fate to their respective undeuterated analogues, so chemical methods that give good indications of bioavailability should extract the fresh more readily available dPAHs and historic more recalcitrant PAHs in similar proportions to those in which they are accumulated in the tissues of test organisms. Cyclodextrin and butanol extractions predicted the bioavailable fraction for earthworms (Eisenia fetida) and plants (Lolium multiflorum) better than the exhaustive extraction. The PAHs accumulated by earthworms had a larger dPAH:PAH ratio than that predicted by chemical methods. The isotope ratio method described here provides an effective way of evaluating other chemical methods to predict bioavailability. - Research highlights: > Isotope ratios can be used to evaluate chemical methods to predict bioavailability. > Chemical methods predicted bioavailability better than exhaustive extractions. > Bioavailability to earthworms was still far from that predicted by chemical methods. - A novel method using isotope ratios to assess the ability of chemical methods to predict PAH bioavailability to soil biota.

  20. Method of heat decomposition for chemical decontaminating resin waste

    International Nuclear Information System (INIS)

    Kikuchi, Akira.

    1988-01-01

    Purpose: To make resin wastes into non-deleterious state, discharge them into a resin waste storage tank of existent radioactive waste processing facility and store and dispose them. Constitution: In the processing of chemical decontaminating resin wastes, iron exchange resins adsorbing chemical decontaminating agents comprising a solution of citric acid, oxalic acid, formic acid and EDTA alone or as a mixture of them are heated to dry, thermally decomposed and then separated from the ion exchange resins. That is, the main ingredients of the chemical decontaminating agents are heat-decomposed when heated and dried at about 250 deg C in air and converted into non-toxic gases such as CO, CO 2 , NO, NO 2 or H 2 O. Further, since combustion or carbonization of the basic materials for the resin is not caused at such a level of temperature, the resin wastes removed with organic acid and chelating agents are transferred to an existent resin waste storage tank and stored therein. In this way, facility cost and radiation exposure can remarkably be decreased. (Kamimura, M.)

  1. A Review of Carbon Nanomaterials’ Synthesis via the Chemical Vapor Deposition (CVD Method

    Directory of Open Access Journals (Sweden)

    Yehia M. Manawi

    2018-05-01

    Full Text Available Carbon nanomaterials have been extensively used in many applications owing to their unique thermal, electrical and mechanical properties. One of the prime challenges is the production of these nanomaterials on a large scale. This review paper summarizes the synthesis of various carbon nanomaterials via the chemical vapor deposition (CVD method. These carbon nanomaterials include fullerenes, carbon nanotubes (CNTs, carbon nanofibers (CNFs, graphene, carbide-derived carbon (CDC, carbon nano-onion (CNO and MXenes. Furthermore, current challenges in the synthesis and application of these nanomaterials are highlighted with suggested areas for future research.

  2. A Review of Carbon Nanomaterials’ Synthesis via the Chemical Vapor Deposition (CVD) Method

    Science.gov (United States)

    Manawi, Yehia M.; Samara, Ayman; Al-Ansari, Tareq; Atieh, Muataz A.

    2018-01-01

    Carbon nanomaterials have been extensively used in many applications owing to their unique thermal, electrical and mechanical properties. One of the prime challenges is the production of these nanomaterials on a large scale. This review paper summarizes the synthesis of various carbon nanomaterials via the chemical vapor deposition (CVD) method. These carbon nanomaterials include fullerenes, carbon nanotubes (CNTs), carbon nanofibers (CNFs), graphene, carbide-derived carbon (CDC), carbon nano-onion (CNO) and MXenes. Furthermore, current challenges in the synthesis and application of these nanomaterials are highlighted with suggested areas for future research. PMID:29772760

  3. Calculation of NMR chemical shifts. 7. Gauge-invariant INDO method

    Science.gov (United States)

    Fukui, H.; Miura, K.; Hirai, A.

    A gauge-invariant INDO method based on the coupled Hartree-Fuck perturbation theory is presented and applied to the calculation of 1H and 13C chemical shifts of hydrocarbons including ring compounds. Invariance of the diamagnetic and paramagnetic shieldings with respect to displacement of the coordinate origin is discussed. Comparison between calculated and experimental results exhibits fairly good agreement, provided that the INDO parameters of Ellis et al. (J. Am. Chem. Soc.94, 4069 (1972)) are used with the inclusion of all multicenter one-electron integrals.

  4. Kinetics of Hydrogen Radical Reactions with Toluene Including Chemical Activation Theory Employing System-Specific Quantum RRK Theory Calibrated by Variational Transition State Theory.

    Science.gov (United States)

    Bao, Junwei Lucas; Zheng, Jingjing; Truhlar, Donald G

    2016-03-02

    Pressure-dependent reactions are ubiquitous in combustion and atmospheric chemistry. We employ a new calibration procedure for quantum Rice-Ramsperger-Kassel (QRRK) unimolecular rate theory within a chemical activation mechanism to calculate the pressure-falloff effect of a radical association with an aromatic ring. The new theoretical framework is applied to the reaction of H with toluene, which is a prototypical reaction in the combustion chemistry of aromatic hydrocarbons present in most fuels. Both the hydrogen abstraction reactions and the hydrogen addition reactions are calculated. Our system-specific (SS) QRRK approach is adjusted with SS parameters to agree with multistructural canonical variational transition state theory with multidimensional tunneling (MS-CVT/SCT) at the high-pressure limit. The new method avoids the need for the usual empirical estimations of the QRRK parameters, and it eliminates the need for variational transition state theory calculations as a function of energy, although in this first application we do validate the falloff curves by comparing SS-QRRK results without tunneling to multistructural microcanonical variational transition state theory (MS-μVT) rate constants without tunneling. At low temperatures, the two approaches agree well with each other, but at high temperatures, SS-QRRK tends to overestimate falloff slightly. We also show that the variational effect is important in computing the energy-resolved rate constants. Multiple-structure anharmonicity, torsional-potential anharmonicity, and high-frequency-mode vibrational anharmonicity are all included in the rate computations, and torsional anharmonicity effects on the density of states are investigated. Branching fractions, which are both temperature- and pressure-dependent (and for which only limited data is available from experiment), are predicted as a function of pressure.

  5. CO2 (carbon dioxide) fixation by applying new chemical absorption-precipitation methods

    International Nuclear Information System (INIS)

    Park, Sangwon; Lee, Min-Gu; Park, Jinwon

    2013-01-01

    CO 2 (carbon dioxide) is the most common greenhouse gas and most of it is emitted from human activities. The methods for CO 2 emission reduction can be divided into physical, chemical, and biochemical methods. Among the physical and chemical methods, CCS (carbon capture and storage) is a well-known reducing technology. However, this method has many disadvantages including the required storage area. In general, CCS requires capture and storage processes. In this study, we propose a method for reusing the absorbed CO 2 either in nature or in industry. The emitted CO 2 was converted into CO 3 2− using a conversion solution, and then made into a carbonate by combining the conversion solution with metal ions at normal temperature and pressure. The resulting carbonate was analyzed using FT-IR (Fourier transform infrared spectroscopy) and XRD (X-ray diffraction). We verified the formation of a solid consisting of calcite and vaterite. In addition, the conversion solution that was used could be reused in the same process of CCS technology. Our study demonstrates a successful method of reducing and reusing emitted CO 2 , thereby making CO 2 a potential future resource. - Highlights: • This study focused on a new CO 2 fixation process method. • In CCS technology, the desorption process requires high thermal energy consumption. • This new method does not require a desorption process because the CO 2 is accomplished through CaCO 3 crystallization. • A new absorption method is possible instead of the conventional absorption-desorption process. • This is not only a rapid reaction for fixing CO 2 , but also economically feasible

  6. Development of Methods for Obtaining Position Image and Chemical Binding Information from Flow Experiments of Porous Media

    Energy Technology Data Exchange (ETDEWEB)

    Haugan, Are

    1998-12-01

    Existing oil reservoirs might be more fully exploited if the properties of the flow of oil and water in porous media were better known. In laboratory experiments it is important to collect as much information as possible to make a descriptive model of the system, including position imaging and chemical binding information. This thesis develops nuclear methods for obtaining position image and chemical binding information from flow experiments of porous media. A combined positron emission tomography and single photon emission computed tomography system to obtain position images, and a time-differential perturbed angular correlation system to obtain chemical binding information, have been built and thoroughly tested. 68 refs., 123 figs., 14 tabs.

  7. Enhancing sewage sludge dewaterability by bioleaching approach with comparison to other physical and chemical conditioning methods.

    Science.gov (United States)

    Liu, Fenwu; Zhou, Jun; Wang, Dianzhan; Zhou, Lixiang

    2012-01-01

    The sewage sludge conditioning process is critical to improve the sludge dewaterability prior to mechanical dewatering. Traditionally, sludge is conditioned by physical or chemical approaches, mostly with the addition of inorganic or organic chemicals. Here we report that bioleaching, an efficient and economical microbial method for the removal of sludge-borne heavy metals, also plays a significant role in enhancing sludge dewaterability. The effects of bioleaching and physical or chemical approaches on sludge dewaterability were compared. The conditioning result of bioleaching by Acidithiobacillus thiooxidans and Acidithiobacillus ferrooxidans on sludge dewatering was investigated and compared with the effects of hydrothermal (121 degrees C for 2 hr), microwave (1050 W for 50 sec), ultrasonic (250 W for 2 min), and chemical conditioning (24% ferric chloride and 68% calcium oxide; dry basis). The results show that the specific resistance to filtration (SRF) or capillary suction time (CST) of sludge is decreased by 93.1% or 74.1%, respectively, after fresh sludge is conditioned by bioleaching, which is similar to chemical conditioning treatment with ferric chloride and calcium oxide but much more effective than other conditioning approaches including hydrothermal, microwave, and ultrasonic conditioning. Furthermore, after sludge dewatering, bioleached sludge filtrate contains the lowest concentrations of chroma (18 times), COD (542 mg/L), total N (TN, 300 mg/L), NH4(+)-N (208 mg/L), and total P (TP, 2 mg/L) while the hydrothermal process resulted in the highest concentration of chroma (660 times), COD (18,155 mg/L), TN (472 mg/L), NH4(+)-N (381 mg/L), and TP (191 mg/L) among these selected conditioning methods. Moreover, unlike chemical conditioning, sludge bioleaching does not result in a significant reduction of organic matter, TN, and TP in the resulting dewatered sludge cake. Therefore, considering sludge dewaterability and the chemical properties of sludge

  8. Chemical and ecological control methods for Epitrix spp.

    Directory of Open Access Journals (Sweden)

    A. G. S. Cuthbertson

    2015-01-01

    Full Text Available Very little information exists in regards to the control options available for potato flea beetles, Epitrix spp. This short review covers both chemical and ecological options currently available for control of Epitrix spp. Synthetic pyrethroids are the weapon of choice for the beetles. However, the impetus in integrated pest management is to do timely (early-season applications with something harsh which will give long-term protection at a time when there are not a lot of beneficials in the field. Finding the balance for control of Epitrix spp. is proving difficult.

  9. Method for separating the isotopes of a chemical element

    International Nuclear Information System (INIS)

    Devienne, F.M.

    1977-01-01

    A beam of positive or negative primary ions of at least one compound of a chemical element is accelerated in order to pass through collision boxes placed in series. As a result of inelastic collisions of the ions with the molecules of a neutral target gas within each collision box, a given percentage of primary ions is dissociated into at least two fragments, one of which is a secondary ion in the form of at least two isotopic species. The collision boxes are brought to a potential V 2 so as to trap preferentially one isotopic species which is condensed within each box. 15 claims, 4 figures

  10. Principles of Single-Laboratory Validation of Analytical Methods for Testing the Chemical Composition of Pesticides

    Energy Technology Data Exchange (ETDEWEB)

    Ambrus, A. [Hungarian Food Safety Office, Budapest (Hungary)

    2009-07-15

    Underlying theoretical and practical approaches towards pesticide formulation analysis are discussed, i.e. general principles, performance characteristics, applicability of validation data, verification of method performance, and adaptation of validated methods by other laboratories. The principles of single laboratory validation of analytical methods for testing the chemical composition of pesticides are outlined. Also the theoretical background is described for performing pesticide formulation analysis as outlined in ISO, CIPAC/AOAC and IUPAC guidelines, including methodological characteristics such as specificity, selectivity, linearity, accuracy, trueness, precision and bias. Appendices I–III hereof give practical and elaborated examples on how to use the Horwitz approach and formulae for estimating the target standard deviation towards acceptable analytical repeatability. The estimation of trueness and the establishment of typical within-laboratory reproducibility are treated in greater detail by means of worked-out examples. (author)

  11. Chemical Mixtures Health Risk Assessment of Environmental Contaminants: Concepts, Methods, Applications

    Science.gov (United States)

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

  12. Chemical Mixtures Health Risk Assessment of Environmental Contaminants: Concepts, Methods, And Applications

    Science.gov (United States)

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

  13. X-ray methods for the chemical characterization of atmospheric aerosols

    International Nuclear Information System (INIS)

    Jaklevic, J.M.; Thompson, A.C.

    1981-05-01

    The development and use of several x-ray methods for the chemical characterization of atmospherical aerosol particulate samples are described. These methods are based on the emission, absorption, and scattering of x-ray photons with emphasis on the optimization for the non-destructive analysis of dilute specimens. Techniques discussed include photon induced energy dispersive x-ray fluorescence, extended x-ray absorption fine structure spectroscopy using synchrotron radiation and high-rate x-ray powder diffractometry using a position-sensitive gas proportional counter. These x-ray analysis methods were applied to the measurement of the chemical compositions of size-segregated aerosol particulate samples obtained with dichotomous samplers. The advantages of the various methods for use in such measurements are described and results are presented. In many cases, the complementary nature of the analytical information obtained from the various measurements is an important factor in the characterization of the sample. For example, the multiple elemental analyses obtained from x-ray fluorescence can be used as a cross check on the major compounds observed by powder diffraction

  14. Assessment of the Authenticity of Herbal Dietary Supplements: Comparison of Chemical and DNA Barcoding Methods.

    Science.gov (United States)

    Pawar, Rahul S; Handy, Sara M; Cheng, Raymond; Shyong, Nicole; Grundel, Erich

    2017-07-01

    About 7 % of the U. S. population reports using botanical dietary supplements. Increased use of such supplements has led to discussions related to their authenticity and quality. Reports of adulteration with substandard materials or pharmaceuticals are of concern because such substitutions, whether inadvertent or deliberate, may reduce the efficacy of specific botanicals or lead to adverse events. Methods for verifying the identity of botanicals include macroscopic and microscopic examinations, chemical analysis, and DNA-based methods including DNA barcoding. Macroscopic and microscopic examinations may fail when a supplement consists of botanicals that have been processed beyond the ability to provide morphological characterizations. Chemical analysis of specific marker compounds encounters problems when these compounds are not distinct to a given species or when purified reference standards are not available. Recent investigations describing DNA barcoding analysis of botanical dietary supplements have raised concerns about the authenticity of the supplements themselves as well as the appropriateness of using DNA barcoding techniques with finished botanical products. We collected 112 market samples of frequently consumed botanical dietary supplements of ginkgo, soy, valerian, yohimbe, and St. John's wort and analyzed each for specific chemical markers (i.e., flavonol glycosides, total isoflavones, total valerenic acids, yohimbine, and hypericins, respectively). We used traditional DNA barcoding techniques targeting the nuclear ITS2 gene and the chloroplast gene psb A- trn H on the same samples to determine the presence of DNA of the labelled ingredient. We compared the results obtained by both methods to assess the contribution of each in determining the identity of the samples. Georg Thieme Verlag KG Stuttgart · New York.

  15. Systematic methods for synthesis and design of sustainable chemical and biochemical processes

    DEFF Research Database (Denmark)

    Gani, Rafiqul

    Chemical and biochemical process design consists of designing the process that can sustainably manufacture an identified chemical product through a chemical or biochemical route. The chemical product tree is potentially very large; starting from a set of basic raw materials (such as petroleum...... for process intensification, sustainable process design, identification of optimal biorefinery models as well as integrated process-control design, and chemical product design. The lecture will present the main concepts, the decomposition based solution approach, the developed methods and tools together...

  16. Effect of Fermentation Methods on Chemical and Microbial ...

    African Journals Online (AJOL)

    Mung flours were fermented using spontaneous and backslopping methods for 72 h and microbial analysis over a period of 72 h fermentation was carried out. The samples were subjected to biochemical test, anti-nutrient and selected mineral and vitamin contents evaluation using standard methods. There was a gradual ...

  17. Decontamination by water jet, chemical and electrochemical methods

    International Nuclear Information System (INIS)

    Gauchon, J.P.; Mordenti, P.; Bezia, C.; Fuentes, P.; Kervegant, Y.; Munoz, C.; Pierlas, C.

    1986-01-01

    The decontamination tests have been carried out on samples coming from representative specimens from primary circuit of the PWR and on samples coming from the emergency feed water piping of the German BWR (Isar). The oxide found in PWR primary loops can only be removed by a two steps process. The initial embrittling step is particularly effective in hot alkaline permanganate medium. Oxidation by ozone treatment is less effective. The second step involves chemical erosion of the metal in nitrofluoric acid in conjonction with ultrasonic agitation. Among the reagents used, only oxalic acid is suitable for electrolytic decontamination. Among the reagents possible for decontamination of the Isar specimens (ferritic steel lined with hematite) halogenous acid in mixture without or with oxygenated water, sulfuric acid, the formic acid/formaldehyde mixture are chosen. Metal erosion with high pressure jet as well as the decontamination efficiency on parts lined with hematite have made possible to determine the best conditions. 33 figs, 29 refs

  18. Evaluation of chemical surface treatment methods for mitigation of PWSCC

    International Nuclear Information System (INIS)

    Dame, C.; Marks, C.; Olender, A.; Farias, J.

    2015-01-01

    As part of its mission to propose innovative and safe technologies to mitigate Primary Water Stress Corrosion Cracking (PWSCC) in Pressurized Water Reactors (PWR), EPRI recently initiated a program to evaluate potential new chemical surface treatments that might delay the occurrence of PWSCC such that no failure of components would be observed during their lifetime. Among the initial screening of more than thirty technologies, seven were selected for a more detailed review. The selected technologies were: nickel and nickel alloy plating, organic inhibitors, chromium-based inhibitors, silicon carbide, titanium-based inhibitors, rare earth metal (REM)-based inhibitors and encapsulation. The conclusions of the review of these technologies were that two of them were worth pursuing, titanium-based and REM-based inhibitors, and that evaluating the radiological consequences of injecting these products in the primary system, as well as assessing their efficacy to mitigate PWSCC, should be prioritized as the next required steps in qualification for implementation. (authors)

  19. Safety evaluation and regulation of chemicals. 2. Impact of regulations - improvement of methods

    Energy Technology Data Exchange (ETDEWEB)

    Homburger, F [ed.

    1985-01-01

    This volume assesses the impact of new scientific knowledge on the testing and regulation of chemicals, including food additives, drugs, cosmetics, pesticides, and other commercial substances. Apart from describing the newest tests, regulations, and risk assessment strategies, chapters reflect changes forced by both the growing need for cost containment and the mounting pressure to find alternatives to animal testing. Based on an international congress, the book also brings the advantage of diversity in the background and nationality of the authors, thus allowing a view of central problems according to the different interests of academics, industry scientists, government scientists, and regulators. The book opens with coverage of national and international regulations designed to prevent and control damage to human health and the environment. Topics range from basic problems of policy design and enforcement to the specific requirements for chemical regulation in developing countries. The next chapters cover new tests, systems, and assays used in in vivo safety testing. Readers will find a critical assessment of tests used to determine teratogenicity, mutagenicity, carcinogenicity, neurotoxicity and chemical lethality. Other topics include factors operating in the public perception of chemical hazards, guidelines for decision making in the management and regulation of risks, and future trends in the methodology of safety evaluation. The volume concludes with an overview of in vitro methods for testing hepatotoxicity. Several short-term in vitro test models and limited in vivo bioassays are presented and evaluated in terms of their capacity to substitute for long-term animal studies. Expert and thorough in its coverage, the book offers a wealth of technical and practical information for toxicologists, pharmacologists, industrial policy makers, and government regulators. (orig.). With 67 figs., 34 tabs.

  20. A new particle-like method for high-speed flows with chemical non-equilibrium

    Directory of Open Access Journals (Sweden)

    Fábio Rodrigues Guzzo

    2010-04-01

    Full Text Available The present work is concerned with the numerical simulation of hypersonic blunt body flows with chemical non-equilibrium. New theoretical and numerical formulations for coupling the chemical reaction to the fluid dynamics are presented and validated. The fluid dynamics is defined for a stationary unstructured mesh and the chemical reaction process is defined for “finite quantities” moving through the stationary mesh. The fluid dynamics is modeled by the Euler equations and the chemical reaction rates by the Arrhenius law. Ideal gases are considered. The thermodynamical data are based on JANNAF tables and Burcat’s database. The algorithm proposed by Liou, known as AUSM+, is implemented in a cell-centered based finite volume method and in an unstructured mesh context. Multidimensional limited MUSCL interpolation method is used to perform property reconstructions and to achieve second-order accuracy in space. The minmod limiter is used. The second order accuracy, five stage, Runge-Kutta time-stepping scheme is employed to perform the time march for the fluid dynamics. The numerical code VODE, which is part of the CHEMKIN-II package, is adopted to perform the time integration for the chemical reaction equations. The freestream reacting fluid is composed of H2 and air at the stoichiometric ratio. The emphasis of the present paper is on the description of the new methodology for handling the coupling of chemical and fluid mechanic processes, and its validation by comparison with the standard time-splitting procedure. The configurations considered are the hypersonic flow over a wedge, in which the oblique detonation wave is induced by an oblique shock wave, and the hypersonic flow over a blunt body. Differences between the solutions obtained with each formulation are presented and discussed, including the effects of grid refinement in each case. The primary objective of such comparisons is the validation of the proposed methodology. Moreover, for

  1. Determination of chemical oxygen demand (COD) using an alternative wet chemical method free of mercury and dichromate.

    Science.gov (United States)

    Kolb, Marit; Bahadir, Müfit; Teichgräber, Burkhard

    2017-10-01

    Worldwide, the standard methods for the determination of the important wastewater parameter chemical oxygen demand (COD) are still based on the use of the hazardous chemicals, mercury sulfate and chromium(VI). However, due to their properties they are meanwhile classified as "priority pollutants" and shall be phased out or banned in the frame of REACH (current European Chemical Law: Registration, Evaluation, Authorization and restriction of Chemicals) by the European Union. Hence, a new wet-chemical method free of mercury and chromium(VI) was developed. Manganese(III) was used as oxidant and silver nitrate for the removal of chloride ions. The quantification was performed by back titration of manganese(III) with iron(II) as done in the standard method. In order to minimize losses of organic substances during the precipitation of silver chloride, suspended and colloid organic matter had to be separated by precipitation of aluminum hydroxide in a first step. In these cases, two fractions, one of the suspended and colloid matters and a second of the dissolved organic substances, are prepared and oxidized separately. The method was tested with potassium hydrogen phthalate (KHP) as conventional COD reference substance and different types of wastewater samples. The oxidation of KHP was reproducible in a COD range of 20-500 mg/L with a mean recovery rate of 88.7% in comparison to the standard COD method (DIN 38409-41). Also in presence of 1000 mg/L chloride a recovery rate of 84.1% was reached. For a series of industrial and municipal wastewater samples a high correlation (R 2  = 0.9935) to the standard method with a mean recovery rate of 78.1% (±5.2%) was determined. Even though the results of the new method are not 100% of the standard method, its high correlation to the standard method and reproducibility offers an environmentally benign alternative method with no need to purchase new laboratory equipment. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Toxicity assessment of chemical contaminants;transition from in vitromethods to novel in vitro methods

    Directory of Open Access Journals (Sweden)

    A.A. Farshad

    2007-04-01

    Full Text Available Exposure to occupational and environmental contaminants is a major contributor to human health problems. Despite significant achievements in the risk assessment of chemicals, the toxicological database, particularly for industrial chemicals, remains limited. Considering there areapproximately 80, 000 chemicals in commerce, and an extremely large number of chemical mixtures, in vivo testing of this large number is unachievable from ethical, economical and scientific perspectives. Therefore, increasing the number of available industrial chemicals andnew products has created a demand for alternatives to animal methods for better safety evaluation. Recent toxicity studies have demonstrated that in vitro methods are capable of rapidly providing toxicity information. In this review, current toxicity test methods for risk evaluation of industrial chemical contaminants are presented. To evaluate the potential applications of  more recent test methods developed for toxicity testing of chemical contaminants are discussed. Although  to be considered more broadly for risk assessment of human chemical exposures. In vitro methods,in vitro toxicology methods cannot exactly mimic the biodynamics of the whole body, in vitro  relationships (QSARs and physiologically based toxicokinetic (PBTK models have a potentialtest systems in combination with the knowledge of quantitative structure activity.

  3. Monitoring a chemical plume remediation via the radio imaging method

    International Nuclear Information System (INIS)

    McCorkle, R.W.; Spence, T.; Linder, K.E.; Betsill, J.D.

    1996-01-01

    In this paper, the authors present the results of a site characterization, monitoring, and remediation effort at Sandia National Laboratories (SNL). The primary objective of the study is to determine the feasibility of using the Radio Imaging Method (RIM) to solve a near-surface waste site characterization problem. The goals are to demonstrate the method during the site characterization phase, then continue with an in-situ monitoring and analysis of the remediation process

  4. Perovskite type nanopowders and thin films obtained by chemical methods

    Directory of Open Access Journals (Sweden)

    Viktor Fruth

    2010-09-01

    Full Text Available The review presents the contribution of the authors, to the preparation of two types of perovskites, namely BiFeO3 and LaCoO3, by innovative methods. The studied perovskites were obtained as powders, films and sintered bodies. Their complex structural and morphological characterization is also presented. The obtained results have underlined the important influence of the method of preparation on the properties of the synthesized perovskites.

  5. Teaching Methods in Biology Education and Sustainability Education Including Outdoor Education for Promoting Sustainability—A Literature Review

    Directory of Open Access Journals (Sweden)

    Eila Jeronen

    2016-12-01

    Full Text Available There are very few studies concerning the importance of teaching methods in biology education and environmental education including outdoor education for promoting sustainability at the levels of primary and secondary schools and pre-service teacher education. The material was selected using special keywords from biology and sustainable education in several scientific databases. The article provides an overview of 24 selected articles published in peer-reviewed scientific journals from 2006–2016. The data was analyzed using qualitative content analysis. Altogether, 16 journals were selected and 24 articles were analyzed in detail. The foci of the analyses were teaching methods, learning environments, knowledge and thinking skills, psychomotor skills, emotions and attitudes, and evaluation methods. Additionally, features of good methods were investigated and their implications for teaching were emphasized. In total, 22 different teaching methods were found to improve sustainability education in different ways. The most emphasized teaching methods were those in which students worked in groups and participated actively in learning processes. Research points toward the value of teaching methods that provide a good introduction and supportive guidelines and include active participation and interactivity.

  6. A New Pseudoinverse Matrix Method For Balancing Chemical Equations And Their Stability

    International Nuclear Information System (INIS)

    Risteski, Ice B.

    2008-01-01

    In this work is given a new pseudoniverse matrix method for balancing chemical equations. Here offered method is founded on virtue of the solution of a Diophantine matrix equation by using of a Moore-Penrose pseudoinverse matrix. The method has been tested on several typical chemical equations and found to be very successful for the all equations in our extensive balancing research. This method, which works successfully without any limitations, also has the capability to determine the feasibility of a new chemical reaction, and if it is feasible, then it will balance the equation. Chemical equations treated here possess atoms with fractional oxidation numbers. Also, in the present work are introduced necessary and sufficient criteria for stability of chemical equations over stability of their extended matrices

  7. A novel fabrication method of carbon electrodes using 3D printing and chemical modification process.

    Science.gov (United States)

    Tian, Pan; Chen, Chaoyang; Hu, Jie; Qi, Jin; Wang, Qianghua; Chen, Jimmy Ching-Ming; Cavanaugh, John; Peng, Yinghong; Cheng, Mark Ming-Cheng

    2017-11-23

    Three-dimensional (3D) printing is an emerging technique in the field of biomedical engineering and electronics. This paper presents a novel biofabrication method of implantable carbon electrodes with several advantages including fast prototyping, patient-specific and miniaturization without expensive cleanroom. The method combines stereolithography in additive manufacturing and chemical modification processes to fabricate electrically conductive carbon electrodes. The stereolithography allows the structures to be 3D printed with very fine resolution and desired shapes. The resin is then chemically modified to carbon using pyrolysis to enhance electrochemical performance. The electrochemical characteristics of 3D printing carbon electrodes are assessed by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The specific capacitance of 3D printing carbon electrodes is much higher than the same sized platinum (Pt) electrode. In-vivo electromyography (EMG) recording, 3D printing carbon electrodes exhibit much higher signal-to-noise ratio (40.63 ± 7.73) than Pt electrodes (14.26 ± 6.83). The proposed biofabrication method is envisioned to enable 3D printing in many emerging applications in biomedical engineering and electronics.

  8. Chemical methods and techniques to monitor early Maillard reaction in milk products; A review.

    Science.gov (United States)

    Aalaei, Kataneh; Rayner, Marilyn; Sjöholm, Ingegerd

    2018-01-23

    Maillard reaction is an extensively studied, yet unresolved chemical reaction that occurs as a result of application of the heat and during the storage of foods. The formation of advanced glycation end products (AGEs) has been the focus of several investigations recently. These molecules which are formed at the advanced stage of the Maillard reaction, are suspected to be involved in autoimmune diseases in humans. Therefore, understanding to which extent this reaction occurs in foods, is of vital significance. Because of their composition, milk products are ideal media for this reaction, especially when application of heat and prolonged storage are considered. Thus, in this work several chemical approaches to monitor this reaction in an early stage are reviewed. This is mostly done regarding available lysine blockage which takes place in the very beginning of the reaction. The most popular methods and their applications to various products are reviewed. The methods including their modifications are described in detail and their findings are discussed. The present paper provides an insight into the history of the most frequently-used methods and provides an overview on the indicators of the Maillard reaction in the early stage with its focus on milk products and especially milk powders.

  9. Teaching Methods in Biology Education and Sustainability Education Including Outdoor Education for Promoting Sustainability--A Literature Review

    Science.gov (United States)

    Jeronen, Eila; Palmberg, Irmeli; Yli-Panula, Eija

    2017-01-01

    There are very few studies concerning the importance of teaching methods in biology education and environmental education including outdoor education for promoting sustainability at the levels of primary and secondary schools and pre-service teacher education. The material was selected using special keywords from biology and sustainable education…

  10. Method for assessment of stormwater treatment facilities - Synthetic road runoff addition including micro-pollutants and tracer.

    Science.gov (United States)

    Cederkvist, Karin; Jensen, Marina B; Holm, Peter E

    2017-08-01

    Stormwater treatment facilities (STFs) are becoming increasingly widespread but knowledge on their performance is limited. This is due to difficulties in obtaining representative samples during storm events and documenting removal of the broad range of contaminants found in stormwater runoff. This paper presents a method to evaluate STFs by addition of synthetic runoff with representative concentrations of contaminant species, including the use of tracer for correction of removal rates for losses not caused by the STF. A list of organic and inorganic contaminant species, including trace elements representative of runoff from roads is suggested, as well as relevant concentration ranges. The method was used for adding contaminants to three different STFs including a curbstone extension with filter soil, a dual porosity filter, and six different permeable pavements. Evaluation of the method showed that it is possible to add a well-defined mixture of contaminants despite different field conditions by having a flexibly system, mixing different stock-solutions on site, and use bromide tracer for correction of outlet concentrations. Bromide recovery ranged from only 12% in one of the permeable pavements to 97% in the dual porosity filter, stressing the importance of including a conservative tracer for correction of contaminant retention values. The method is considered useful in future treatment performance testing of STFs. The observed performance of the STFs is presented in coming papers. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Detailed balance method for chemical potential determination in Monte Carlo and molecular dynamics simulations

    International Nuclear Information System (INIS)

    Fay, P.J.; Ray, J.R.; Wolf, R.J.

    1994-01-01

    We present a new, nondestructive, method for determining chemical potentials in Monte Carlo and molecular dynamics simulations. The method estimates a value for the chemical potential such that one has a balance between fictitious successful creation and destruction trials in which the Monte Carlo method is used to determine success or failure of the creation/destruction attempts; we thus call the method a detailed balance method. The method allows one to obtain estimates of the chemical potential for a given species in any closed ensemble simulation; the closed ensemble is paired with a ''natural'' open ensemble for the purpose of obtaining creation and destruction probabilities. We present results for the Lennard-Jones system and also for an embedded atom model of liquid palladium, and compare to previous results in the literature for these two systems. We are able to obtain an accurate estimate of the chemical potential for the Lennard-Jones system at higher densities than reported in the literature

  12. Development of polishing methods for Chemical Vapor Deposited Silicon Carbide mirrors for synchrotron radiation

    International Nuclear Information System (INIS)

    Fuchs, B.A.; Brown, N.J.

    1987-01-01

    Material properties of Chemical Vapor Deposited Silicon Carbide (CVD SiC) make it ideal for use in mirrors for synchrotron radiation experiments. We developed methods to grind and polish flat samples of CVD SiC down to measured surface roughness values as low as 1.1 Angstroms rms. We describe the processing details, including observations we made during trial runs with alternative processing recipes. We conclude that pitch polishing using progressively finer diamond abrasive, augmented with specific water based lubricants and additives, produces superior results. Using methods based on these results, a cylindrical and a toroidal mirror, each about 100 x 300mm, were respectively finished by Continental Optical and Frank Cooke, Incorporated. WYCO Interferometry shows these mirrors have surface roughness less than 5.7 Angstroms rms. These mirrors have been installed on the LLNL/UC X-ray Calibration and Standards Facility at the Stanford Synthrotron Radiation Laboratory

  13. An Energy Efficiency Evaluation Method Based on Energy Baseline for Chemical Industry

    OpenAIRE

    Yao, Dong-mei; Zhang, Xin; Wang, Ke-feng; Zou, Tao; Wang, Dong; Qian, Xin-hua

    2016-01-01

    According to the requirements and structure of ISO 50001 energy management system, this study proposes an energy efficiency evaluation method based on energy baseline for chemical industry. Using this method, the energy plan implementation effect in the processes of chemical production can be evaluated quantitatively, and evidences for system fault diagnosis can be provided. This method establishes the energy baseline models which can meet the demand of the different kinds of production proce...

  14. Flavoring Chemicals in E-Cigarettes: Diacetyl, 2,3-Pentanedione, and Acetoin in a Sample of 51 Products, Including Fruit-, Candy-, and Cocktail-Flavored E-Cigarettes.

    Science.gov (United States)

    Allen, Joseph G; Flanigan, Skye S; LeBlanc, Mallory; Vallarino, Jose; MacNaughton, Piers; Stewart, James H; Christiani, David C

    2016-06-01

    There are > 7,000 e-cigarette flavors currently marketed. Flavoring chemicals gained notoriety in the early 2000s when inhalation exposure of the flavoring chemical diacetyl was found to be associated with a disease that became known as "popcorn lung." There has been limited research on flavoring chemicals in e-cigarettes. We aimed to determine if the flavoring chemical diacetyl and two other high-priority flavoring chemicals, 2,3-pentanedione and acetoin, are present in a convenience sample of flavored e-cigarettes. We selected 51 types of flavored e-cigarettes sold by leading e-cigarette brands and flavors we deemed were appealing to youth. E-cigarette contents were fully discharged and the air stream was captured and analyzed for total mass of diacetyl, 2,3-pentanedione, and acetoin, according to OSHA method 1012. At least one flavoring chemical was detected in 47 of 51 unique flavors tested. Diacetyl was detected above the laboratory limit of detection in 39 of the 51 flavors tested, ranging from below the limit of quantification to 239 μg/e-cigarette. 2,3-Pentanedione and acetoin were detected in 23 and 46 of the 51 flavors tested at concentrations up to 64 and 529 μg/e-cigarette, respectively. Because of the associations between diacetyl and bronchiolitis obliterans and other severe respiratory diseases observed in workers, urgent action is recommended to further evaluate this potentially widespread exposure via flavored e-cigarettes. Allen JG, Flanigan SS, LeBlanc M, Vallarino J, MacNaughton P, Stewart JH, Christiani DC. 2016. Flavoring chemicals in e-cigarettes: diacetyl, 2,3-pentanedione, and acetoin in a sample of 51 products, including fruit-, candy-, and cocktail-flavored e-cigarettes. Environ Health Perspect 124:733-739; http://dx.doi.org/10.1289/ehp.1510185.

  15. Reduction in Acidity by Chemical and Microbiological Methods and Their Effect on Moslavac Wine Quality

    OpenAIRE

    Herjavec, Stanka; Majdak, Ana; Tupajić, Pavica; Redžepović, Sulejman; Orlić, Sandi

    2003-01-01

    Changes in chemical composition and sensory properties caused by chemical and microbiological methods of deacidification in Moslavac (syn. Furmint) wines were investigated. Alcoholic fermentation of Moslavac musts was carried out with two different strains of the yeasts Saccharomyces paradoxus. There were no marked differences in chemical composition among the wines. Compared to the control microbiological deacidification of wines by Oenococcus oeni resulted in a complete decomposition of mal...

  16. Destruction and waste treatment methods used in a chemical agent disposal project. Memorandum report

    Energy Technology Data Exchange (ETDEWEB)

    McAndless, J.; Fedor, V.; Kinderwater, T.

    1992-10-01

    This report describes the equipment and methods used to thermally decontaminate scrap metal and destroy stockpiles of nerve agents, mustard and lewisite chemical warfare agents. Mustard was destroyed by direct incineration whereas the nerve agents and lewisite were chemically neutralized. The arsenic waste from the lewisite neutralization process was chemically-fixated in concrete for final disposal by landfilling. The scrap metal was incinerated and rendered suitable for recycling into metal feedstock.

  17. Laboratory studies of 235U enrichment by chemical separation methods

    International Nuclear Information System (INIS)

    Daloisi, P.J.; Orlett, M.J.; Tracy, J.W.; Saraceno, A.J.

    1976-01-01

    Laboratory experiments on 235 U enrichment processes based on column redox ion exchange, electrodialysis, and gas exchange chromatography performed from August 1972 to September 1974 are summarized. Effluent from a 50 to 50 weight mixture of U +4 and U +6 (as UO 2 2+ ), at a total uranium concentration of 5 mg U per ml in 0.25N H 2 SO 4 -0.03N NaF solution, passing through a 100 cm length cation exchange column at 0.5 ml/min flow rates, was enriched in 235 U by 1.00090 +- .00012. The enriched fraction was mostly in the +6 valence form while the depleted fraction was U +4 retained on the resin. At flow rates of 2 ml/min, the enrichment factor decreases to 1.00033 +- .00003. In the electrodialysis experiments, the fraction of uranium diffusing through the membranes (mostly as +6 valence state) in 4.2 hours is enriched in 235 U by 1.00096 +- .00012. Gas exchange chromatography tests involved dynamic and static exposure of UF 6 over NaF. In dynamic tests, no significant change in isotopic abundance occurred in the initial one-half weight cut of UF 6 . The measured relative 235 U/ 238 U mole ratios were 1.00004 +- .00004 for these runs. In static runs, enrichment became evident. For the NaF(UF 6 )/sub x/-UF 6 system, there is 235 U depletion in the gas phase, with a single-stage factor of 1.00033 at 100 0 C and 1.00025 at 25 0 C after 10 days of equilibration. The single-stage or unit holdup time is impractically long for all three chemical processes

  18. Physico-chemical properties of manufactured nanomaterials - Characterisation and relevant methods. An outlook based on the OECD Testing Programme.

    NARCIS (Netherlands)

    Rasmussen, Kirsten; Rauscher, Hubert; Mech, Agnieszka; Riego Sintes, Juan; Gilliland, Douglas; González, Mar; Kearns, Peter; Moss, Kenneth; Visser, Maaike; Groenewold, Monique; Bleeker, Eric A J

    Identifying and characterising nanomaterials require additional information on physico-chemical properties and test methods, compared to chemicals in general. Furthermore, regulatory decisions for chemicals are usually based upon certain toxicological properties, and these effects may not be

  19. Apparatus and method for solid fuel chemical looping combustion

    Science.gov (United States)

    Siriwardane, Ranjani V; Weber, Justin M

    2015-04-14

    The disclosure provides an apparatus and method utilizing fuel reactor comprised of a fuel section, an oxygen carrier section, and a porous divider separating the fuel section and the oxygen carrier section. The porous divider allows fluid communication between the fuel section and the oxygen carrier section while preventing the migration of solids of a particular size. Maintaining particle segregation between the oxygen carrier section and the fuel section during solid fuel gasification and combustion processes allows gases generated in either section to participate in necessary reactions while greatly mitigating issues associated with mixture of the oxygen carrier with char or ash products. The apparatus and method may be utilized with an oxygen uncoupling oxygen carrier such as CuO, Mn.sub.3O.sub.4, or Co.sub.3O.sub.4, or utilized with a CO/H.sub.2 reducing oxygen carrier such as Fe.sub.2O.sub.3.

  20. EFFECTS OF EXTRACTION METHODS ON PHYSICO-CHEMICAL ...

    African Journals Online (AJOL)

    The relative density value ranged from 0.9 to 0.92 at 29°C (room temperature). Both oil samples were in liquid state at room temperature and boiling points varied from 94°C-to 98°C for solvent extracted oil and hydraulic press oil respectively. The results showed thatJhe method ofextraction imposed significant changes on ...

  1. Methods for chemical analysis of water and wastes

    Energy Technology Data Exchange (ETDEWEB)

    1979-03-01

    This manual provides test procedures approved for the monitoring of water supplies, waste discharges, and ambient waters, under the Safe Drinking Water Act, the National Pollutant Discharge Elimination System, and Ambient Monitoring Requirements of Section 106 and 208 of Public Law 92-500. The test methods have been selected to meet the needs of federal legislation and to provide guidance to laboratories engaged in the protection of human health and the aquatic environment.

  2. A LITERATURE REVIEW OF WIPE SAMPLING METHODS FOR CHEMICAL WARFARE AGENTS AND TOXIC INDUSTRIAL CHEMICALS

    Science.gov (United States)

    Wipe sampling is an important technique for the estimation of contaminant deposition in buildings, homes, or outdoor surfaces as a source of possible human exposure. Numerousmethods of wipe sampling exist, and each method has its own specification for the type of wipe, we...

  3. The Frontlines of Medicine Project: a proposal for the standardized communication of emergency department data for public health uses including syndromic surveillance for biological and chemical terrorism.

    Science.gov (United States)

    Barthell, Edward N; Cordell, William H; Moorhead, John C; Handler, Jonathan; Feied, Craig; Smith, Mark S; Cochrane, Dennis G; Felton, Christopher W; Collins, Michael A

    2002-04-01

    The Frontlines of Medicine Project is a collaborative effort of emergency medicine (including emergency medical services and clinical toxicology), public health, emergency government, law enforcement, and informatics. This collaboration proposes to develop a nonproprietary, "open systems" approach for reporting emergency department patient data. The common element is a standard approach to sending messages from individual EDs to regional oversight entities that could then analyze the data received. ED encounter data could be used for various public health initiatives, including syndromic surveillance for chemical and biological terrorism. The interlinking of these regional systems could also permit public health surveillance at a national level based on ED patient encounter data. Advancements in the Internet and Web-based technologies could allow the deployment of these standardized tools in a rapid time frame.

  4. A robust two-node, 13 moment quadrature method of moments for dilute particle flows including wall bouncing

    Science.gov (United States)

    Sun, Dan; Garmory, Andrew; Page, Gary J.

    2017-02-01

    For flows where the particle number density is low and the Stokes number is relatively high, as found when sand or ice is ingested into aircraft gas turbine engines, streams of particles can cross each other's path or bounce from a solid surface without being influenced by inter-particle collisions. The aim of this work is to develop an Eulerian method to simulate these types of flow. To this end, a two-node quadrature-based moment method using 13 moments is proposed. In the proposed algorithm thirteen moments of particle velocity, including cross-moments of second order, are used to determine the weights and abscissas of the two nodes and to set up the association between the velocity components in each node. Previous Quadrature Method of Moments (QMOM) algorithms either use more than two nodes, leading to increased computational expense, or are shown here to give incorrect results under some circumstances. This method gives the computational efficiency advantages of only needing two particle phase velocity fields whilst ensuring that a correct combination of weights and abscissas is returned for any arbitrary combination of particle trajectories without the need for any further assumptions. Particle crossing and wall bouncing with arbitrary combinations of angles are demonstrated using the method in a two-dimensional scheme. The ability of the scheme to include the presence of drag from a carrier phase is also demonstrated, as is bouncing off surfaces with inelastic collisions. The method is also applied to the Taylor-Green vortex flow test case and is found to give results superior to the existing two-node QMOM method and is in good agreement with results from Lagrangian modelling of this case.

  5. Chemical bridges for enhancing hydrogen storage by spillover and methods for forming the same

    Science.gov (United States)

    Yang, Ralph T.; Li, Yingwei; Qi, Gongshin; Lachawiec, Jr., Anthony J.

    2012-12-25

    A composition for hydrogen storage includes a source of hydrogen atoms, a receptor, and a chemical bridge formed between the source and the receptor. The chemical bridge is formed from a precursor material. The receptor is adapted to receive hydrogen spillover from the source.

  6. CHEMICALS

    CERN Multimedia

    Medical Service

    2002-01-01

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

  7. Quality control of chemical heat treatment by the fractography method

    International Nuclear Information System (INIS)

    Tamarina, A.M.; Parygin, V.A.; Karpov, V.N.

    1978-01-01

    A fractographic investigation is carried out of fracture of a nitrided layer of 38KhMYuA steel and of cemented and cyanided layers of 12KhM3A steel. It is established that a fracture of the nitrided layer consists of three zones of crystalline facets: 1) a surface zone of fine crystalline facets located in a single plane and having the appearance of a white band (Σ-phase zone); 2) zone of acicular facets whose presence is due to the break-down of the carbonitride phase; 3) zone of large facets of boundary breakdown. The fractures of cemented and cyanided samples consist of multiple fine facets of multi-face shapes. It has been found that the depth and the microstructure of a diffusion layer in steel after chemothermal processing can be most rapidly and objectively evaluated by the fractographic method

  8. [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.

  9. 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.

  10. Chemical protein synthesis: Inventing synthetic methods to decipher how proteins work.

    Science.gov (United States)

    Kent, Stephen

    2017-09-15

    Total chemical synthesis of proteins has been rendered practical by the chemical ligation principle: chemoselective condensation of unprotected peptide segments equipped with unique, mutually reactive functional groups, enabled by formation of a non-native replacement for the peptide bond. Ligation chemistries are briefly described, including native chemical ligation - thioester-mediated, amide-forming reaction at Xaa-Cys sites - and its extensions. Case studies from the author's own works are used to illustrate the utility and applications of chemical protein synthesis. Selected recent developments in the field are briefly discussed. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Catalogue of methods of calculation, interpolation, smoothing, and reduction for the physical, chemical, and biological parameters of deep hydrology (CATMETH) (NODC Accession 7700442)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The document presents the methods, formulas and citations used by the BNDO to process physical, chemical, and biological data for deep hydrology including...

  12. DRES Database of Methods for the Analysis of Chemical Warfare Agents

    National Research Council Canada - National Science Library

    D'Agostino, Paul

    1997-01-01

    .... Update of the database continues as an ongoing effort and the DRES Database of Methods for the Analysis of Chemical Warfare Agents is available panel in hardcopy form or as a softcopy Procite or Wordperfect file...

  13. A comparison of the microstructures and electrochemical capacitive properties of 2 graphenes prepared by arc discharge method and chemical method

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, H.; Yang, Y. [Research Inst. of Chemical Defense, Beijing (China); Univ. of Science and Technology, Beijing (China); Cao, G.; Xu, B. [Research Inst. of Chemical Defense, Beijing (China)

    2010-07-01

    In this study, 2 kinds of graphene materials were prepared using both arc discharge and chemical methods. The pore structures and electrochemical capacitive properties of the materials were investigated. A mesopore structure was obtained for the graphene prepared using the arc discharge method, with a capacitance of 12.9 F/g and a high rate capability when used in electrochemical applications. The graphene prepared with the chemical method demonstrated a more highly developed micropore structure and capacitances greater than 70 F/g. However, rate performance for the graphene was normal. 2 figs.

  14. A new cascade method for studying isotope effect in chemical exchange system without valance change

    International Nuclear Information System (INIS)

    Wen Xiaoning; Luo Wenzong

    1987-01-01

    A new cascade method for studying isotope effect in chemical exchange system without valance change is developed and described. This method is simple to use and consumes less extractant as compared with the commonly used Woodward method. It is also convenient for unstable systems

  15. A Chemical Risk Ranking and Scoring Method for the Selection of Harmful Substances to be Specially Controlled in Occupational Environments

    Science.gov (United States)

    Shin, Saemi; Moon, Hyung-Il; Lee, Kwon Seob; Hong, Mun Ki; Byeon, Sang-Hoon

    2014-01-01

    This study aimed to devise a method for prioritizing hazardous chemicals for further regulatory action. To accomplish this objective, we chose appropriate indicators and algorithms. Nine indicators from the Globally Harmonized System of Classification and Labeling of Chemicals were used to identify categories to which the authors assigned numerical scores. Exposure indicators included handling volume, distribution, and exposure level. To test the method devised by this study, sixty-two harmful substances controlled by the Occupational Safety and Health Act in Korea, including acrylamide, acrylonitrile, and styrene were ranked using this proposed method. The correlation coefficients between total score and each indicator ranged from 0.160 to 0.641, and those between total score and hazard indicators ranged from 0.603 to 0.641. The latter were higher than the correlation coefficients between total score and exposure indicators, which ranged from 0.160 to 0.421. Correlations between individual indicators were low (−0.240 to 0.376), except for those between handling volume and distribution (0.613), suggesting that each indicator was not strongly correlated. The low correlations between each indicator mean that the indicators and independent and were well chosen for prioritizing harmful chemicals. This method proposed by this study can improve the cost efficiency of chemical management as utilized in occupational regulatory systems. PMID:25419874

  16. A Chemical Risk Ranking and Scoring Method for the Selection of Harmful Substances to be Specially Controlled in Occupational Environments

    Directory of Open Access Journals (Sweden)

    Saemi Shin

    2014-11-01

    Full Text Available This study aimed to devise a method for prioritizing hazardous chemicals for further regulatory action. To accomplish this objective, we chose appropriate indicators and algorithms. Nine indicators from the Globally Harmonized System of Classification and Labeling of Chemicals were used to identify categories to which the authors assigned numerical scores. Exposure indicators included handling volume, distribution, and exposure level. To test the method devised by this study, sixty-two harmful substances controlled by the Occupational Safety and Health Act in Korea, including acrylamide, acrylonitrile, and styrene were ranked using this proposed method. The correlation coefficients between total score and each indicator ranged from 0.160 to 0.641, and those between total score and hazard indicators ranged from 0.603 to 0.641. The latter were higher than the correlation coefficients between total score and exposure indicators, which ranged from 0.160 to 0.421. Correlations between individual indicators were low (−0.240 to 0.376, except for those between handling volume and distribution (0.613, suggesting that each indicator was not strongly correlated. The low correlations between each indicator mean that the indicators and independent and were well chosen for prioritizing harmful chemicals. This method proposed by this study can improve the cost efficiency of chemical management as utilized in occupational regulatory systems.

  17. Chemical Ecology of the Colorado Potato Beetle, Leptinotarsa decemlineata (Say (Coleoptera: Chrysomelidae, and Potential for Alternative Control Methods

    Directory of Open Access Journals (Sweden)

    François J. Verheggen

    2012-12-01

    Full Text Available The Colorado potato beetle (CPB has been a major insect pest to potato farming for over 150 years and various control methods have been established to reduce its impact on potato fields. Crop rotation and pesticide use are currently the most widely used approaches, although alternative methods are being developed. Here we review the role of various volatile and nonvolatile chemicals involved in behavior changes of CPB that may have potential for their control. First, we describe all volatile and nonvolatile chemicals involved in host plant localization and acceptance by CPB beetles, including glycoalcaloids and host plant volatiles used as kairomones. In the second section, we present the chemical signals used by CPB in intraspecific communication, including sex and aggregation pheromones. Some of these chemicals are used by natural enemies of CPBs to locate their prey and are presented in the third section. The last section of this review is devoted a discussion of the potential of some natural chemicals in biological control of CPB and to approaches that already reached efficient field applications.

  18. Comparison of chemical, electrophoretic and in vitro digestion methods for predicting fish meal nutritive quality

    DEFF Research Database (Denmark)

    Bassompierre, M.; Larsen, K.L.; Zimmermann, W.

    1998-01-01

    utilization, NPU, biological value, BV, and true digestibility, TD), capillary electrophoresis (sodium dodecyl sulphate-capillary gel electrophoresis, SDS-CGE)) and an in vitro enzymatic assay (trinitrobenzene sulphonic acid-based closed system with rainbow trout enzyme extract) were used for further...... different quantities of water-soluble protein (wsp). A low-temperature-dried FM was employed as a reference. Acquired chemical data for each of the FMs included amino acid analysis and proximal composition (protein, fat, ash, ammonia, titration, salt, moisture). Biological methods in rat (net protein...... comparisons with FM wsp content. A high correlation (R = 0.97; P titration volume was observed. In contrast to BV and NPU (R = 0.98; P

  19. Use of thermal neutron reflection method for chemical analysis of bulk samples

    International Nuclear Information System (INIS)

    Papp, A.; Csikai, J.

    2014-01-01

    Microscopic, σ β , and macroscopic, Σ β , reflection cross-sections of thermal neutrons averaged over bulk samples as a function of thickness (z) are given. The σ β values are additive even for bulk samples in the z=0.5–8 cm interval and so the σ βmol (z) function could be given for hydrogenous substances, including some illicit drugs, explosives and hiding materials of ∼1000 cm 3 dimensions. The calculated excess counts agree with the measured R(z) values. For the identification of concealed objects and chemical analysis of bulky samples, different neutron methods need to be used simultaneously. - Highlights: • Check the proposed analytical expression for the description of the flux. • Determination of the reflection cross-sections averaged over bulk samples. • Data rendered to estimate the excess counts for various materials

  20. Use of thermal neutron reflection method for chemical analysis of bulk samples

    Energy Technology Data Exchange (ETDEWEB)

    Papp, A., E-mail: papppa@atomki.hu [Institute of Nuclear Research of the Hungarian Academy of Sciences, (ATOMKI), 4001 Debrecen, Pf. 51 (Hungary); Csikai, J. [Institute of Nuclear Research of the Hungarian Academy of Sciences, (ATOMKI), 4001 Debrecen, Pf. 51 (Hungary); Institute of Experimental Physics, University Debrecen (IEP), 4010 Debrecen-10, Pf. 105 (Hungary)

    2014-09-11

    Microscopic, σ{sub β}, and macroscopic, Σ{sub β}, reflection cross-sections of thermal neutrons averaged over bulk samples as a function of thickness (z) are given. The σ{sub β} values are additive even for bulk samples in the z=0.5–8 cm interval and so the σ{sub βmol}(z) function could be given for hydrogenous substances, including some illicit drugs, explosives and hiding materials of ∼1000 cm{sup 3} dimensions. The calculated excess counts agree with the measured R(z) values. For the identification of concealed objects and chemical analysis of bulky samples, different neutron methods need to be used simultaneously. - Highlights: • Check the proposed analytical expression for the description of the flux. • Determination of the reflection cross-sections averaged over bulk samples. • Data rendered to estimate the excess counts for various materials.

  1. A sensitive multi-residue method for the determination of 35 micropollutants including pharmaceuticals, iodinated contrast media and pesticides in water.

    Science.gov (United States)

    Valls-Cantenys, Carme; Scheurer, Marco; Iglesias, Mònica; Sacher, Frank; Brauch, Heinz-Jürgen; Salvadó, Victoria

    2016-09-01

    A sensitive, multi-residue method using solid-phase extraction followed by liquid chromatography-tandem mass spectrometry (LC-MS/MS) was developed to determine a representative group of 35 analytes, including corrosion inhibitors, pesticides and pharmaceuticals such as analgesic and anti-inflammatory drugs, five iodinated contrast media, β-blockers and some of their metabolites and transformation products in water samples. Few other methods are capable of determining such a broad range of contrast media together with other analytes. We studied the parameters affecting the extraction of the target analytes, including sorbent selection and extraction conditions, their chromatographic separation (mobile phase composition and column) and detection conditions using two ionisation sources: electrospray ionisation (ESI) and atmospheric pressure chemical ionisation (APCI). In order to correct matrix effects, a total of 20 surrogate/internal standards were used. ESI was found to have better sensitivity than APCI. Recoveries ranging from 79 to 134 % for tap water and 66 to 144 % for surface water were obtained. Intra-day precision, calculated as relative standard deviation, was below 34 % for tap water and below 21 % for surface water, groundwater and effluent wastewater. Method quantification limits (MQL) were in the low ng L(-1) range, except for the contrast agents iomeprol, amidotrizoic acid and iohexol (22, 25.5 and 17.9 ng L(-1), respectively). Finally, the method was applied to the analysis of 56 real water samples as part of the validation procedure. All of the compounds were detected in at least some of the water samples analysed. Graphical Abstract Multi-residue method for the determination of micropollutants including pharmaceuticals, iodinated contrast media and pesticides in waters by LC-MS/MS.

  2. TRANSAT-- method for detecting the conserved helices of functional RNA structures, including transient, pseudo-knotted and alternative structures.

    Science.gov (United States)

    Wiebe, Nicholas J P; Meyer, Irmtraud M

    2010-06-24

    The prediction of functional RNA structures has attracted increased interest, as it allows us to study the potential functional roles of many genes. RNA structure prediction methods, however, assume that there is a unique functional RNA structure and also do not predict functional features required for in vivo folding. In order to understand how functional RNA structures form in vivo, we require sophisticated experiments or reliable prediction methods. So far, there exist only a few, experimentally validated transient RNA structures. On the computational side, there exist several computer programs which aim to predict the co-transcriptional folding pathway in vivo, but these make a range of simplifying assumptions and do not capture all features known to influence RNA folding in vivo. We want to investigate if evolutionarily related RNA genes fold in a similar way in vivo. To this end, we have developed a new computational method, Transat, which detects conserved helices of high statistical significance. We introduce the method, present a comprehensive performance evaluation and show that Transat is able to predict the structural features of known reference structures including pseudo-knotted ones as well as those of known alternative structural configurations. Transat can also identify unstructured sub-sequences bound by other molecules and provides evidence for new helices which may define folding pathways, supporting the notion that homologous RNA sequence not only assume a similar reference RNA structure, but also fold similarly. Finally, we show that the structural features predicted by Transat differ from those assuming thermodynamic equilibrium. Unlike the existing methods for predicting folding pathways, our method works in a comparative way. This has the disadvantage of not being able to predict features as function of time, but has the considerable advantage of highlighting conserved features and of not requiring a detailed knowledge of the cellular

  3. Method of fabricating electrodes including high-capacity, binder-free anodes for lithium-ion batteries

    Science.gov (United States)

    Ban, Chunmei; Wu, Zhuangchun; Dillon, Anne C.

    2017-01-10

    An electrode (110) is provided that may be used in an electrochemical device (100) such as an energy storage/discharge device, e.g., a lithium-ion battery, or an electrochromic device, e.g., a smart window. Hydrothermal techniques and vacuum filtration methods were applied to fabricate the electrode (110). The electrode (110) includes an active portion (140) that is made up of electrochemically active nanoparticles, with one embodiment utilizing 3d-transition metal oxides to provide the electrochemical capacity of the electrode (110). The active material (140) may include other electrochemical materials, such as silicon, tin, lithium manganese oxide, and lithium iron phosphate. The electrode (110) also includes a matrix or net (170) of electrically conductive nanomaterial that acts to connect and/or bind the active nanoparticles (140) such that no binder material is required in the electrode (110), which allows more active materials (140) to be included to improve energy density and other desirable characteristics of the electrode. The matrix material (170) may take the form of carbon nanotubes, such as single-wall, double-wall, and/or multi-wall nanotubes, and be provided as about 2 to 30 percent weight of the electrode (110) with the rest being the active material (140).

  4. Theoretical study of the electronic structure of f-element complexes by quantum chemical methods

    International Nuclear Information System (INIS)

    Vetere, V.

    2002-09-01

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

  5. Advances and Perspectives in Chemical Imaging in Cellular Environments Using Electrochemical Methods

    Directory of Open Access Journals (Sweden)

    Robert A. Lazenby

    2018-05-01

    Full Text Available This review discusses a broad range of recent advances (2013–2017 in chemical imaging using electrochemical methods, with a particular focus on techniques that have been applied to study cellular processes, or techniques that show promise for use in this field in the future. Non-scanning techniques such as microelectrode arrays (MEAs offer high time-resolution (<10 ms imaging; however, at reduced spatial resolution. In contrast, scanning electrochemical probe microscopies (SEPMs offer higher spatial resolution (as low as a few nm per pixel imaging, with images collected typically over many minutes. Recent significant research efforts to improve the spatial resolution of SEPMs using nanoscale probes and to improve the temporal resolution using fast scanning have resulted in movie (multiple frame imaging with frame rates as low as a few seconds per image. Many SEPM techniques lack chemical specificity or have poor selectivity (defined by the choice of applied potential for redox-active species. This can be improved using multifunctional probes, ion-selective electrodes and tip-integrated biosensors, although additional effort may be required to preserve sensor performance after miniaturization of these probes. We discuss advances to the field of electrochemical imaging, and technological developments which are anticipated to extend the range of processes that can be studied. This includes imaging cellular processes with increased sensor selectivity and at much improved spatiotemporal resolution than has been previously customary.

  6. Characterization and photo-chemical applications of nano-ZnO prepared by wet chemical and thermal decomposition methods

    International Nuclear Information System (INIS)

    Mousa, M.A.; Bayoumy, W.A.A.; Khairy, M.

    2013-01-01

    Graphical abstract: - Highlights: • Nano-ZnO particles were synthesized by soft-wet precipitation and dry methods. • ZnO nanoparticle with different morphologies was obtained. • Nano ZnO samples showed a high photocatalytic activity. • ZnO nanoparticle showed strong ultraviolet emission at room temperature. • The samples showed high biological activity depending on their synthetic method. - Abstract: Nano-crystalline ZnO particles were synthesized using two different routes: soft-wet and dry methods. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to identify the particles structures and morphologies, while X-ray diffraction (XRD) was used for verifying the particles crystal structure. The thermal stabilities of the particles were examined through thermal gravimetric analysis technique and their surface areas were calculated using BET method. Moreover, the photocatalytic activities were evaluated using UV–vis spectroscopy and photoluminescence (PL) characterization. The results showed that all the prepared ZnO samples possess a hexagonal wurtzite structure with high purity. Different particle sizes and morphologies of spheres, rods and wires were obtained depending on the preparation method used. Particle sizes obtained by the dry method are smaller than that found by the wet chemical method. The effects of both particle size and morphology on each of surface as well as optical properties, photocatalytic activity, dye/ZnO solar cell efficiency and biological activity have been studied and discussed

  7. Applications of the conjugate gradient FFT method in scattering and radiation including simulations with impedance boundary conditions

    Science.gov (United States)

    Barkeshli, Kasra; Volakis, John L.

    1991-01-01

    The theoretical and computational aspects related to the application of the Conjugate Gradient FFT (CGFFT) method in computational electromagnetics are examined. The advantages of applying the CGFFT method to a class of large scale scattering and radiation problems are outlined. The main advantages of the method stem from its iterative nature which eliminates a need to form the system matrix (thus reducing the computer memory allocation requirements) and guarantees convergence to the true solution in a finite number of steps. Results are presented for various radiators and scatterers including thin cylindrical dipole antennas, thin conductive and resistive strips and plates, as well as dielectric cylinders. Solutions of integral equations derived on the basis of generalized impedance boundary conditions (GIBC) are also examined. The boundary conditions can be used to replace the profile of a material coating by an impedance sheet or insert, thus, eliminating the need to introduce unknown polarization currents within the volume of the layer. A general full wave analysis of 2-D and 3-D rectangular grooves and cavities is presented which will also serve as a reference for future work.

  8. Evaluation and Comparison of Multiple Test Methods, Including Real-time PCR, for Legionella Detection in Clinical Specimens

    Science.gov (United States)

    Peci, Adriana; Winter, Anne-Luise; Gubbay, Jonathan B.

    2016-01-01

    Legionella is a Gram-negative bacterium that can cause Pontiac fever, a mild upper respiratory infection and Legionnaire’s disease, a more severe illness. We aimed to compare the performance of urine antigen, culture, and polymerase chain reaction (PCR) test methods and to determine if sputum is an acceptable alternative to the use of more invasive bronchoalveolar lavage (BAL). Data for this study included specimens tested for Legionella at Public Health Ontario Laboratories from 1st January, 2010 to 30th April, 2014, as part of routine clinical testing. We found sensitivity of urinary antigen test (UAT) compared to culture to be 87%, specificity 94.7%, positive predictive value (PPV) 63.8%, and negative predictive value (NPV) 98.5%. Sensitivity of UAT compared to PCR was 74.7%, specificity 98.3%, PPV 77.7%, and NPV 98.1%. Out of 146 patients who had a Legionella-positive result by PCR, only 66 (45.2%) also had a positive result by culture. Sensitivity for culture was the same using either sputum or BAL (13.6%); sensitivity for PCR was 10.3% for sputum and 12.8% for BAL. Both sputum and BAL yield similar results regardless testing methods (Fisher Exact p-values = 1.0, for each test). In summary, all test methods have inherent weaknesses in identifying Legionella; therefore, more than one testing method should be used. Obtaining a single specimen type from patients with pneumonia limits the ability to diagnose Legionella, particularly when urine is the specimen type submitted. Given ease of collection and similar sensitivity to BAL, clinicians are encouraged to submit sputum in addition to urine when BAL submission is not practical from patients being tested for Legionella. PMID:27630979

  9. Evaluation and comparison of multiple test methods, including real-time PCR, for Legionella detection in clinical specimens.

    Directory of Open Access Journals (Sweden)

    Adriana Peci

    2016-08-01

    Full Text Available Legionella is a gram-negative bacterium that can cause Pontiac fever, a mild upper respiratory infection and Legionnaire’s disease, a more severe illness. We aimed to compare the performance of urine antigen, culture and PCR test methods and to determine if sputum is an alternative to the use of more invasive bronchoalveolar lavage (BAL. Data for this study included specimens tested for Legionella at PHOL from January 1, 2010 to April 30, 2014, as part of routine clinical testing. We found sensitivity of UAT compared to culture to be 87%, specificity 94.7%, positive predictive value (PPV 63.8% and negative predictive value (NPV 98.5%. Sensitivity of UAT compared to PCR was 74.7%, specificity 98.3%, PPV 77.7% and NPV 98.1%. Of 146 patients who had a Legionella positive result by PCR, only 66(45.2% also had a positive result by culture. Sensitivity for culture was the same using either sputum or BAL (13.6%; sensitivity for PCR was 10.3% for sputum and 12.8% for BAL. Both sputum and BAL yield similar results despite testing methods (Fisher Exact p-values=1.0, for each test. In summary, all test methods have inherent weaknesses in identifying Legionella; thereforemore than one testing method should be used. Obtaining a single specimen type from patients with pneumonia limits the ability to diagnose Legionella, particularly when urine is the specimen type submitted. Given ease of collection, and similar sensitivity to BAL, clinicians are encouraged to submit sputum in addition to urine when BAL submission is not practical, from patients being tested for Legionella.

  10. How to compute isomerization energies of organic molecules with quantum chemical methods.

    Science.gov (United States)

    Grimme, Stefan; Steinmetz, Marc; Korth, Martin

    2007-03-16

    The reaction energies for 34 typical organic isomerizations including oxygen and nitrogen heteroatoms are investigated with modern quantum chemical methods that have the perspective of also being applicable to large systems. The experimental reaction enthalpies are corrected for vibrational and thermal effects, and the thus derived "experimental" reaction energies are compared to corresponding theoretical data. A series of standard AO basis sets in combination with second-order perturbation theory (MP2, SCS-MP2), conventional density functionals (e.g., PBE, TPSS, B3-LYP, MPW1K, BMK), and new perturbative functionals (B2-PLYP, mPW2-PLYP) are tested. In three cases, obvious errors of the experimental values could be detected, and accurate coupled-cluster [CCSD(T)] reference values have been used instead. It is found that only triple-zeta quality AO basis sets provide results close enough to the basis set limit and that sets like the popular 6-31G(d) should be avoided in accurate work. Augmentation of small basis sets with diffuse functions has a notable effect in B3-LYP calculations that is attributed to intramolecular basis set superposition error and covers basic deficiencies of the functional. The new methods based on perturbation theory (SCS-MP2, X2-PLYP) are found to be clearly superior to many other approaches; that is, they provide mean absolute deviations of less than 1.2 kcal mol-1 and only a few (computational thermochemistry methods.

  11. Chemical characterization of materials relevant to nuclear technology using neutron and proton based nuclear analytical methods

    International Nuclear Information System (INIS)

    Acharya, R.

    2014-01-01

    Nuclear analytical techniques (NATs), utilizing neutron and proton based nuclear reactions and subsequent measurement of gamma rays, are capable of chemical characterization of various materials at major to trace concentration levels. The present article deals with the recent developments and applications of conventional and k0-based internal monostandard (i) neutron activation analysis (NAA) and (ii) prompt gamma ray NAA (PGNAA) methods as well as (iii) in situ current normalized particle induced gamma ray emission (PIGE). The materials that have been analyzed by NAA and PGNAA include (i) nuclear reactor structural materials like zircaloys, stainless steels, Ni alloys, high purity aluminium and graphite and (ii) uranium oxide, U-Th mixed oxides, uranium ores and minerals. Internal monostandard NAA (IM-NAA) method with in situ detection efficiency was used to analyze large and non-standard geometry samples and standard-less compositional characterization was carried out for zircaloys and stainless steels. PIGE methods using proton beams were standardized for quantification of low Z elements (Li to Ti) and applied for compositional analysis of borosilicate glass and lithium titanate (Li 2 TiO 3 ) samples and quantification of total B and its isotopic composition of B ( 10 B/ 11 B) in boron based neutron absorbers like B 4 C. (author)

  12. Method for Non-Invasive Determination of Chemical Properties of Aqueous Solutions

    Science.gov (United States)

    Todd, Paul W. (Inventor); Jones, Alan (Inventor); Thomas, Nathan A. (Inventor)

    2016-01-01

    A method for non-invasively determining a chemical property of an aqueous solution is provided. The method provides the steps of providing a colored solute having a light absorbance spectrum and transmitting light through the colored solute at two different wavelengths. The method further provides the steps of measuring light absorbance of the colored solute at the two different transmitted light wavelengths, and comparing the light absorbance of the colored solute at the two different wavelengths to determine a chemical property of an aqueous solution.

  13. A method for assessing residual NAPL based on organic chemical concentrations in soil samples

    International Nuclear Information System (INIS)

    Feenstra, S.; Mackay, D.M.; Cherry, J.A.

    1991-01-01

    Ground water contamination by non-aqueous phase liquid (NAPL) chemicals is a serious concern at many industrial facilities and waste disposal sites. NAPL in the form of immobile residual contamination, or pools of mobile or potentially mobile NAPL, can represent continuing sources of ground water contamination. In order to develop rational and cost-effective plans for remediation of soil and ground water contamination at such sites, it is essential to determine if non-aqueous phase liquid (NAPL) chemicals are present in the subsurface and delineate the zones of NAPL contamination. Qualitatively, soil analyses that exhibit chemical concentrations in the percent range or >10,000 mg/kg would generally be considered to indicate the presence of NAPL. However, the results of soil analyses are seldom used in a quantitative manner to assess the possible presence of residual NAPL contamination when chemical concentrations are lower and the presence of NAPL is not obvious. The assessment of the presence of NAPL in soil samples is possible using the results of chemical and physical analyses of the soil, and the fundamental principles of chemical partitioning in unsaturated or saturated soil. The method requires information on the soil of the type typically considered in ground water contamination studies and provides a simple tool for the investigators of chemical spill and waste disposal sites to assess whether soil chemical analyses indicate the presence of residual NAPL in the subsurface

  14. X-ray photon-in/photon-out methods for chemical imaging

    Energy Technology Data Exchange (ETDEWEB)

    Marcus, Matthew A.

    2010-03-24

    Most interesting materials in nature are heterogeneous, so it is useful to have analytical techniques with spatial resolution sufficient to resolve these heterogeneities.This article presents the basics of X-ray photon-in/photon-out chemical imaging. This family of methods allows one to derive images reflectingthe chemical state of a given element in a complex sample, at micron or deep sub-micron scale. X-ray chemical imaging is relatively non-destructiveand element-selective, and requires minimal sample preparation. The article presents the basic concepts and some considerations of data takingand data analysis, along with some examples.

  15. NMR determination of chemically related metals in solution as a new method of inorganic analysis

    International Nuclear Information System (INIS)

    Fedorov, L.A.

    1989-01-01

    An NMR spectroscopic method for the determination of chemically related metals in solution is suggested. The metals are determined in complexes with specially selected polydentate ligands. Structural requirements to ligands, analytical properties and general limits of the application of the method are discussed. (orig.)

  16. The method of modelling of relationships between hardenability and chemical composition of the constructional alloy steels

    International Nuclear Information System (INIS)

    Dobrzanski, L.A.; Sitek, W.

    1998-01-01

    Basing on the experimental results of the hardenability investigations, which employed Jominy method, the model of the neural networks was developed and fully verified experimentally. The model makes it possible to obtain Jominy hardenability curves basing on the steel chemical composition. The model of neural networks, making it possible to design the steel chemical composition, basing on the known Jominy hardenability curve shape, was developed also and fully verified numerically. The practical usability of the models developed is presented. (author)

  17. Thermodynamic method for obtaining the solubilities of complex medium-sized chemicals in pure and mixed solvents

    DEFF Research Database (Denmark)

    Abildskov, Jens; O'Connell, J.P.

    2005-01-01

    This paper extends our previous simplified approach to using group contribution methods and limited data to determine differences in solubility of sparingly soluble complex chemicals as the solvent is changed. New applications include estimating temperature dependence and the effect of adding cos....... Though we present no new solution theory, the paper shows an especially efficient use of thermodynamic models for solvent and cosolvent selection for product formulations. Examples and discussion of applications are given. (c) 2004 Elsevier B.V. All rights reserved.......This paper extends our previous simplified approach to using group contribution methods and limited data to determine differences in solubility of sparingly soluble complex chemicals as the solvent is changed. New applications include estimating temperature dependence and the effect of adding...

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

    Science.gov (United States)

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

    2018-06-01

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

  19. Contributors to Frequent Telehealth Alerts Including False Alerts for Patients with Heart Failure: A Mixed Methods Exploration

    Science.gov (United States)

    Radhakrishna, K.; Bowles, K.; Zettek-Sumner, A.

    2013-01-01

    Summary Background Telehealth data overload through high alert generation is a significant barrier to sustained adoption of telehealth for managing HF patients. Objective To explore the factors contributing to frequent telehealth alerts including false alerts for Medicare heart failure (HF) patients admitted to a home health agency. Materials and Methods A mixed methods design that combined quantitative correlation analysis of patient characteristic data with number of telehealth alerts and qualitative analysis of telehealth and visiting nurses’ notes on follow-up actions to patients’ telehealth alerts was employed. All the quantitative and qualitative data was collected through retrospective review of electronic records of the home heath agency. Results Subjects in the study had a mean age of 83 (SD = 7.6); 56% were female. Patient co-morbidities (ppatient characteristics along with establishing patient-centered telehealth outcome goals may allow meaningful generation of telehealth alerts. Reducing avoidable telehealth alerts could vastly improve the efficiency and sustainability of telehealth programs for HF management. PMID:24454576

  20. Chemical surface modification of calcium carbonate particles with stearic acid using different treating methods

    Energy Technology Data Exchange (ETDEWEB)

    Cao, Zhi [Materials Research Institute, Athlone Institute of Technology, Athlone (Ireland); Daly, Michael [Mergon International, Castlepollard, Westmeath (Ireland); Clémence, Lopez [Polytech Grenoble, Grenoble (France); Geever, Luke M.; Major, Ian; Higginbotham, Clement L. [Materials Research Institute, Athlone Institute of Technology, Athlone (Ireland); Devine, Declan M., E-mail: ddevine@ait.ie [Materials Research Institute, Athlone Institute of Technology, Athlone (Ireland)

    2016-08-15

    Highlights: • The effects of stearic acid treatment for CaCO{sub 3} are highly influenced by the treatment method of application. • A new stearic acid treatment method, namely, combination treatment for CaCO{sub 3} was developed. • The combination treatment was compared with two of the existing methods dry and wet method. • The negative effects of void coalescence was minimised by the utilization of the combination method. - Abstract: Calcium carbonate (CaCO{sub 3}) is often treated with stearic acid (SA) to decrease its polarity. However, the method of application of the SA treatments has a strong influence on CaCO{sub 3} thermoplastic composite’s interfacial structure and distribution. Several of papers describe the promising effects of SA surface treatment, but few compare the treatment process and its effect on the properties of the final thermoplastic composite. In the current study, we assessed a new SA treatment method, namely, complex treatment for polymer composite fabrication with HDPE. Subsequently, a comparative study was performed between the “complex” process and the other existing methods. The composites were assessed using different experiments included scanning electron microscopy (SEM), void content, density, wettability, differential scanning calorimetry (DSC), and tensile tests. It was observed that the “complex” surface treatment yielded composites with a significantly lower voids content and higher density compared to other surface treatments. This indicates that after the “complex” treatment process, the CaCO{sub 3} particles and HDPE matrix are more tightly packed than other methods. DSC and wettability results suggest that the “wet” and “complex” treated CaCO{sub 3} composites had a significantly higher heat of fusion and moisture resistance compared to the “dry” treated CaCO{sub 3} composites. Furthermore, “wet” and “complex” treated CaCO{sub 3} composites have a significantly higher tensile

  1. Difference in target definition using three different methods to include respiratory motion in radiotherapy of lung cancer.

    Science.gov (United States)

    Sloth Møller, Ditte; Knap, Marianne Marquard; Nyeng, Tine Bisballe; Khalil, Azza Ahmed; Holt, Marianne Ingerslev; Kandi, Maria; Hoffmann, Lone

    2017-11-01

    Minimizing the planning target volume (PTV) while ensuring sufficient target coverage during the entire respiratory cycle is essential for free-breathing radiotherapy of lung cancer. Different methods are used to incorporate the respiratory motion into the PTV. Fifteen patients were analyzed. Respiration can be included in the target delineation process creating a respiratory GTV, denoted iGTV. Alternatively, the respiratory amplitude (A) can be measured based on the 4D-CT and A can be incorporated in the margin expansion. The GTV expanded by A yielded GTV + resp, which was compared to iGTV in terms of overlap. Three methods for PTV generation were compared. PTV del (delineated iGTV expanded to CTV plus PTV margin), PTV σ (GTV expanded to CTV and A was included as a random uncertainty in the CTV to PTV margin) and PTV ∑ (GTV expanded to CTV, succeeded by CTV linear expansion by A to CTV + resp, which was finally expanded to PTV ∑ ). Deformation of tumor and lymph nodes during respiration resulted in volume changes between the respiratory phases. The overlap between iGTV and GTV + resp showed that on average 7% of iGTV was outside the GTV + resp implying that GTV + resp did not capture the tumor during the full deformable respiration cycle. A comparison of the PTV volumes showed that PTV σ was smallest and PTV Σ largest for all patients. PTV σ was in mean 14% (31 cm 3 ) smaller than PTV del , while PTV del was 7% (20 cm 3 ) smaller than PTV Σ . PTV σ yields the smallest volumes but does not ensure coverage of tumor during the full respiratory motion due to tumor deformation. Incorporating the respiratory motion in the delineation (PTV del ) takes into account the entire respiratory cycle including deformation, but at the cost, however, of larger treatment volumes. PTV Σ should not be used, since it incorporates the disadvantages of both PTV del and PTV σ .

  2. An Energy Efficiency Evaluation Method Based on Energy Baseline for Chemical Industry

    Directory of Open Access Journals (Sweden)

    Dong-mei Yao

    2016-01-01

    Full Text Available According to the requirements and structure of ISO 50001 energy management system, this study proposes an energy efficiency evaluation method based on energy baseline for chemical industry. Using this method, the energy plan implementation effect in the processes of chemical production can be evaluated quantitatively, and evidences for system fault diagnosis can be provided. This method establishes the energy baseline models which can meet the demand of the different kinds of production processes and gives the general solving method of each kind of model according to the production data. Then the energy plan implementation effect can be evaluated and also whether the system is running normally can be determined through the baseline model. Finally, this method is used on cracked gas compressor unit of ethylene plant in some petrochemical enterprise; it can be proven that this method is correct and practical.

  3. Chemical Footprint Method for Improved Communication of Freshwater Ecotoxicity Impacts in the Context of Ecological Limits

    DEFF Research Database (Denmark)

    Bjørn, Anders; Diamond, Miriam; Birkved, Morten

    2014-01-01

    The ecological footprint method has been successful in communicating environmental impacts of anthropogenic activities in the context of ecological limits. We introduce a chemical footprint method that expresses ecotoxicity impacts from anthropogenic chemical emissions as the dilution needed...... to avoid freshwater ecosystem damage. The indicator is based on USEtox characterization factors with a modified toxicity reference point. Chemical footprint results can be compared to the actual dilution capacity within the geographic vicinity receiving the emissions to estimate whether its ecological...... limit has been exceeded and hence whether emissions can be expected to be environmentally sustainable. The footprint method was illustrated using two case studies. The first was all inventoried emissions from European countries and selected metropolitan areas in 2004, which indicated that the dilution...

  4. Chemical Pretreatment Methods for the Production of Cellulosic Ethanol: Technologies and Innovations

    Directory of Open Access Journals (Sweden)

    Edem Cudjoe Bensah

    2013-01-01

    Full Text Available Pretreatment of lignocellulose has received considerable research globally due to its influence on the technical, economic and environmental sustainability of cellulosic ethanol production. Some of the most promising pretreatment methods require the application of chemicals such as acids, alkali, salts, oxidants, and solvents. Thus, advances in research have enabled the development and integration of chemical-based pretreatment into proprietary ethanol production technologies in several pilot and demonstration plants globally, with potential to scale-up to commercial levels. This paper reviews known and emerging chemical pretreatment methods, highlighting recent findings and process innovations developed to offset inherent challenges via a range of interventions, notably, the combination of chemical pretreatment with other methods to improve carbohydrate preservation, reduce formation of degradation products, achieve high sugar yields at mild reaction conditions, reduce solvent loads and enzyme dose, reduce waste generation, and improve recovery of biomass components in pure forms. The use of chemicals such as ionic liquids, NMMO, and sulphite are promising once challenges in solvent recovery are overcome. For developing countries, alkali-based methods are relatively easy to deploy in decentralized, low-tech systems owing to advantages such as the requirement of simple reactors and the ease of operation.

  5. Adaptation of chemical methods of analysis to the matrix of pyrite-acidified mining lakes

    International Nuclear Information System (INIS)

    Herzsprung, P.; Friese, K.

    2000-01-01

    Owing to the unusual matrix of pyrite-acidified mining lakes, the analysis of chemical parameters may be difficult. A number of methodological improvements have been developed so far, and a comprehensive validation of methods is envisaged. The adaptation of the available methods to small-volume samples of sediment pore waters and the adaptation of sensitivity to the expected concentration ranges is an important element of the methods applied in analyses of biogeochemical processes in mining lakes [de

  6. The phase-resolved photoacoustic method to indicate chemical assignments of paracetamol

    Science.gov (United States)

    Camilotti, J. G.; Somer, A.; Costa, G. F.; Ribeiro, M. A.; Bonardi, C.; Cruz, G. K.; Gómez, S. L.; Beltrame, F. L.; Medina, A. N.; Sato, F.; Astrath, N. G. C.; Novatski, A.

    2014-03-01

    In this work, the phase-resolved photoacoustic method was applied to provide specific information on the chemical assignments of paracetamol in the near-infrared region. Two broad bands, centered at 1370 and 1130 nm, were well-resolved using this method, making it possible to assign the peaks centered at 1398, 1355 and 1295 nm to a C-H combination from a CH3 structure and the peak at 1305 nm to a C-H combination from the aromatic ring. This information represents a new finding in chemical studies regarding this medicament.

  7. In silico toxicology: computational methods for the prediction of chemical toxicity

    KAUST Repository

    Raies, Arwa B.; Bajic, Vladimir B.

    2016-01-01

    Determining the toxicity of chemicals is necessary to identify their harmful effects on humans, animals, plants, or the environment. It is also one of the main steps in drug design. Animal models have been used for a long time for toxicity testing. However, in vivo animal tests are constrained by time, ethical considerations, and financial burden. Therefore, computational methods for estimating the toxicity of chemicals are considered useful. In silico toxicology is one type of toxicity assessment that uses computational methods to analyze, simulate, visualize, or predict the toxicity of chemicals. In silico toxicology aims to complement existing toxicity tests to predict toxicity, prioritize chemicals, guide toxicity tests, and minimize late-stage failures in drugs design. There are various methods for generating models to predict toxicity endpoints. We provide a comprehensive overview, explain, and compare the strengths and weaknesses of the existing modeling methods and algorithms for toxicity prediction with a particular (but not exclusive) emphasis on computational tools that can implement these methods and refer to expert systems that deploy the prediction models. Finally, we briefly review a number of new research directions in in silico toxicology and provide recommendations for designing in silico models.

  8. In silico toxicology: computational methods for the prediction of chemical toxicity

    KAUST Repository

    Raies, Arwa B.

    2016-01-06

    Determining the toxicity of chemicals is necessary to identify their harmful effects on humans, animals, plants, or the environment. It is also one of the main steps in drug design. Animal models have been used for a long time for toxicity testing. However, in vivo animal tests are constrained by time, ethical considerations, and financial burden. Therefore, computational methods for estimating the toxicity of chemicals are considered useful. In silico toxicology is one type of toxicity assessment that uses computational methods to analyze, simulate, visualize, or predict the toxicity of chemicals. In silico toxicology aims to complement existing toxicity tests to predict toxicity, prioritize chemicals, guide toxicity tests, and minimize late-stage failures in drugs design. There are various methods for generating models to predict toxicity endpoints. We provide a comprehensive overview, explain, and compare the strengths and weaknesses of the existing modeling methods and algorithms for toxicity prediction with a particular (but not exclusive) emphasis on computational tools that can implement these methods and refer to expert systems that deploy the prediction models. Finally, we briefly review a number of new research directions in in silico toxicology and provide recommendations for designing in silico models.

  9. New Multigrid Method Including Elimination Algolithm Based on High-Order Vector Finite Elements in Three Dimensional Magnetostatic Field Analysis

    Science.gov (United States)

    Hano, Mitsuo; Hotta, Masashi

    A new multigrid method based on high-order vector finite elements is proposed in this paper. Low level discretizations in this method are obtained by using low-order vector finite elements for the same mesh. Gauss-Seidel method is used as a smoother, and a linear equation of lowest level is solved by ICCG method. But it is often found that multigrid solutions do not converge into ICCG solutions. An elimination algolithm of constant term using a null space of the coefficient matrix is also described. In three dimensional magnetostatic field analysis, convergence time and number of iteration of this multigrid method are discussed with the convectional ICCG method.

  10. Rapid continuous chemical methods for studies of nuclei far from stability

    CERN Document Server

    Trautmann, N; Eriksen, D; Gaggeler, H; Greulich, N; Hickmann, U; Kaffrell, N; Skarnemark, G; Stender, E; Zendel, M

    1981-01-01

    Fast continuous separation methods accomplished by combining a gas-jet recoil-transport system with a variety of chemical systems are described. Procedures for the isolation of individual elements from fission product mixtures with the multistage solvent extraction facility SISAK are presented. Thermochromatography in connection with a gas-jet has been studied as a technique for on-line separation of volatile fission halides. Based on chemical reactions in a gas-jet system itself separation procedures for tellurium, selenium and germanium from fission products have been worked out. All the continuous chemical methods can be performed within a few seconds. The application of such procedures to the investigation of nuclides far from the line of beta -stability is illustrated by a few examples. (16 refs).

  11. Ammonia-free chemical bath method for deposition of microcrystalline cadmium selenide films

    International Nuclear Information System (INIS)

    Lokhande, C.D.; Lee, Eun-Ho; Jung, Kwang-Deog; Joo, Oh-Shim

    2005-01-01

    Chemical deposition of cadmium selenide (CdSe) films has been carried out from alkaline aqueous solution containing Cd 2+ and Se 2- ions. In general, the alkaline pH of the CdSe deposition bath has been adjusted by addition of liquid ammonia. However, the use of ammonia in large-scale chemical deposition method represents an environmental problem due to its volatility and toxicity. The volatility of ammonia changes the pH of deposition bath and results into irreproducible film properties. In the present paper, ammonia-free and weak alkaline (pH < 9.0) chemical method for cadmium selenide film has been developed. The cadmium selenide films are microcrystalline (grain size 0.5-0.7 μm) with hexagonal crystal structure. These films are photoactive and therefore, useful in photo conversion of light into electrical power

  12. Thyme and basil essential oils included in edible coatings as a natural preserving method of oilseed kernels.

    Science.gov (United States)

    Riveros, Cecilia G; Nepote, Valeria; Grosso, Nelson R

    2016-01-15

    Sunflower seeds are susceptible to developing rancidity and off-flavours through lipid oxidation. Edible coatings and essential oils have proven antioxidant properties in different food products. The purpose of this study was to evaluate the combined effect of using an edible coating and thyme and basil essential oils to preserve the chemical and sensory quality parameters of roasted sunflower seeds during storage. 50% DPPH inhibitory concentration (IC50) values of 0.278 and 0.0997 µg mL(-1) were observed for thyme and basil, respectively. On storage day 40, peroxide values were 80.68, 70.28, 68.43, 49.31 and 33.87 mEq O2 kg(-1) in roasted sunflower seeds (RS), roasted sunflower seeds coated with carboxymethyl cellulose (CMC) (RS-CMC), roasted sunflower seeds coated with CMC added with basil (RS-CMC-A), thyme (RS-CMC-T) and butylated hydroxytoluene (RS-CMC-BHT), respectively. RS-CMC-T and RS-CMC-BHT presented the lowest peroxide values, conjugated dienes and p-anisidine values during storage. RS-CMC-BHT, RS-CMC-T, and RS-CMC-A showed the lowest oxidized and cardboard flavour intensity ratings. On storage day 40, roasted sunflower flavour intensity ratings were higher in RS-CMC-T and RS-CMC-A. Thyme and basil essential oils added to the CMC coating improved the sensory stability of this product during storage, but only thyme essential oil increased their chemical stability. © 2015 Society of Chemical Industry.

  13. Simple method to transfer graphene from metallic catalytic substrates to flexible surfaces without chemical etching

    International Nuclear Information System (INIS)

    Ko, P J; Takahashi, H; Sakai, H; Thu, T V; Okada, H; Sandhu, A; Koide, S

    2013-01-01

    Graphene shows promise for applications in flexible electronics. Here, we describe our procedure to transfer graphene grown on copper substrates by chemical vapor deposition to polydimethylsiloxane (PDMS) and SiO 2 /Si surfaces. The transfer of graphene was achieved by a simple, etching-free method onto flexible PDMS substrates.

  14. Computer Aided Methods & Tools for Separation & Purification of Fine Chemical & Pharmaceutical Products

    DEFF Research Database (Denmark)

    Afonso, Maria B.C.; Soni, Vipasha; Mitkowski, Piotr Tomasz

    2006-01-01

    An integrated approach that is particularly suitable for solving problems related to product-process design from the fine chemicals, agrochemicals, food and pharmaceutical industries is presented together with the corresponding methods and tools, which forms the basis for an integrated computer...

  15. Measurement of interfacial areas with the chemical method for a system with alternating dispersed phases

    NARCIS (Netherlands)

    van Woezik, B.A.A.; Westerterp, K.R.

    2000-01-01

    The interfacial area for a liquid–liquid system has been determined by the chemical reaction method. The saponification of butyl formate ester with 8 M sodium hydroxide has been used to this end. A correlation has been derived to describe the mole flux of ester through the interface and the kinetic

  16. Non- chemical methods of seed treatment for control of seed- borne pathogens on vegetables

    NARCIS (Netherlands)

    Amein, T.; Wright, S.A.I.; Wickstrom, M.; Schmitt, A.; Koch, E.; Wolf, van der J.M.; Groot, S.P.C.; Werner, S.; Jahn, M.

    2006-01-01

    The aim of EU-project "Seed Treatments for Organic Vegetable Production" (STOVE) was to evaluate non-chemical methods for control of seed-borne pathogens in organic vegetable production. Physical (hot air, hot water and electron) and biologi-cal (microorganisms and different agents of natural

  17. A new ultrasonic method to detect chemical additives in branded milk

    Indian Academy of Sciences (India)

    Abstract. A new ultrasonic method – thermoacoustic analysis – is reported for the detection of the added chemical preservatives in branded milk. The nature of variation and shift in the thermal response of the acoustic parameters specific acoustic impedance, adiabatic compressibility and Rao's specific sound velocity for ...

  18. The overlapping distribution method to compute chemical potentials of chain molecules

    NARCIS (Netherlands)

    Mooij, G.C.A.M.; Frenkel, D.

    1994-01-01

    The chemical potential of continuously deformable chain molecules can be estimated by measuring the average Rosenbluth weight associated with the virtual insertion of a molecule. We show how to generalize the overlapping-distribution method of Bennett to histograms of Rosenbluth weights. In this way

  19. Surface Nano Structures Manufacture Using Batch Chemical Processing Methods for Tooling Applications

    DEFF Research Database (Denmark)

    Tosello, Guido; Calaon, Matteo; Gavillet, J.

    2011-01-01

    The patterning of large surface areas with nano structures by using chemical batch processes to avoid using highenergy intensive nano machining processes was investigated. The capability of different surface treatment methods of creating micro and nano structured adaptable mould inserts for subse...

  20. Method for the deconvolution of incompletely resolved CARS spectra in chemical dynamics experiments

    International Nuclear Information System (INIS)

    Anda, A.A.; Phillips, D.L.; Valentini, J.J.

    1986-01-01

    We describe a method for deconvoluting incompletely resolved CARS spectra to obtain quantum state population distributions. No particular form for the rotational and vibrational state distribution is assumed, the population of each quantum state is treated as an independent quantity. This method of analysis differs from previously developed approaches for the deconvolution of CARS spectra, all of which assume that the population distribution is Boltzmann, and thus are limited to the analysis of CARS spectra taken under conditions of thermal equilibrium. The method of analysis reported here has been developed to deconvolute CARS spectra of photofragments and chemical reaction products obtained in chemical dynamics experiments under nonequilibrium conditions. The deconvolution procedure has been incorporated into a computer code. The application of that code to the deconvolution of CARS spectra obtained for samples at thermal equilibrium and not at thermal equilibrium is reported. The method is accurate and computationally efficient

  1. Chemical methods for Sm-Nd separation and its application in isotopic geological dating

    International Nuclear Information System (INIS)

    Guo Qifeng.

    1990-01-01

    Three chemical methods for Sm-Nd separation are mainly desribed: low chromatography of butamone-ammonium thiocyanate for hight concentration Sm and Nd separation, P 240 column chromatography for medium concentration Sm-Nd separation, and pressure ion exchange for low concentration Sm-Nd. The first Sm-Nd synchrone obtained in China with Sm-Nd methods is introduced and Sm-Nd isotopic geological dating in Early Archaean rocks in eastern Hebei has been determined

  2. Food irradiation: physical-chemical, technological and economical background and competing methods of food preservation

    International Nuclear Information System (INIS)

    Zagorski, Z.P.

    1994-01-01

    Physical, chemical and technical as well as economical background of food preservation by irradiation have been performed. The radiation sources and the elements of radiation chemistry connected with their use in food irradiation process have been shown. The problems of dosimetry and endurance of dose uniformity for processed products have been also discussed. The other methods of food preservation and their weakness and advantages have been also presented and compared with food irradiation method

  3. Method and multichannel equipment for chemical analysis by X-ray emission

    International Nuclear Information System (INIS)

    Bacso, J.; Horkay, Gy.; Kalinka, G.; Kertesz, Zs.; Kiss Varga, M.; Lakatos, T.; Mathe, Gy.; Paal, A.; Sulik, B.

    1978-01-01

    In the patent a simple method and an apparatus are described for chemical analysis based on X-ray emission generated by irradiation. The concentrations of pre-selected elements can be determined easily by this method using an equipment containing microprocessor. The number of channels and the elements to be determined can be modified by a simple change in the program. (Sz.J.)

  4. Chemical sensors and the development of potentiometric methods for liquid media analysis

    International Nuclear Information System (INIS)

    Vlasov, Yu.G.; Kolodnikov, V.V.; Ermolenko, Yu.E.; Mikhajlova, S.S.

    1996-01-01

    Aspects of applying indirect potentiometric determination to chemical analysis are considered. Among them are the standard and modified addition and subtraction methods, the multiple addition method, and potentiometric titration using ion-selective electrodes as indicators. These methods significantly extend the capabilities of ion-selective potentiometric analysis. Conditions for the applicability of the above-mentioned methods to various samples (Cd, REE, Th, iodides and others) are discussed using all available ion-selective electrodes as examples. 162 refs., 2 figs., 5 tabs

  5. Further development of LLNA:DAE method as stand-alone skin-sensitization testing method and applied for evaluation of relative skin-sensitizing potency between chemicals.

    Science.gov (United States)

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

    2015-04-01

    To date, there has been no well-established local lymph node assay (LLNA) that includes an elicitation phase. Therefore, we developed a modified local lymph node assay with an elicitation phase (LLNA:DAE) to discriminate true skin sensitizers from chemicals that gave borderline positive results and previously reported this assay. To develop the LLNA:DAE method as a useful stand-alone testing method, we investigated the complete procedure for the LLNA:DAE method using hexyl cinnamic aldehyde (HCA), isoeugenol, and 2,4-dinitrochlorobenzene (DNCB) as test compounds. We defined the LLNA:DAE procedure as follows: in the dose-finding test, four concentrations of chemical applied to dorsum of the right ear on days 1, 2, and 3 and dorsum of both ears on day 10. Ear thickness and skin irritation score were measured on days 1, 3, 5, 10, and 12. Local lymph nodes were excised and weighed on day 12. The test dose for the primary LLNA:DAE study was selected as the dose that gave the highest left ear lymph node weight in the dose-finding study, or the lowest dose that produced a left ear lymph node of over 4 mg. This procedure was validated using nine different chemicals. Furthermore, qualitative relationship was observed between the degree of elicitation response in the left ear lymph node and the skin sensitizing potency of 32 chemicals tested in this study and the previous study. These results indicated that LLNA:DAE method was as first LLNA method that was able to evaluate the skin sensitizing potential and potency in elicitation response.

  6. In vitro methods for hazard assessment of industrial chemicals – opportunities and challenges

    Directory of Open Access Journals (Sweden)

    Chin Lin eWong

    2015-05-01

    Full Text Available Allergic contact dermatitis (ACD is a delayed-type hypersensitivity immune reaction mediated by T-lymphocytes as a result of repeated exposure of an allergen primarily on skin. ACD accounts for up to 95% of occupational skin diseases (OSDs, with epoxy resins implicated as one of the most common causes of ACD. Efficient high-throughput in vitro screening for accurate identification of compounds and materials that may pose hazardous risks in the workplace is crucial. At present, the murine local lymph node assay (LLNA is the ‘method of choice’ for predicting the sensitizing potency of contact allergens. As the 3Rs principles of reduction, refinement and replacement in animal testing has gained political and economic momentum, several in vitro screening methods have been developed for identifying potential contact allergens. To date, these latter methods have been utilized primarily to assess the skin sensitizing potential of the chemical components of cosmetic products with scant research attention as to the applicability of these methods to industrial chemicals, particularly epoxy resins. Herein we review the currently utilized in vitro methods and identify the knowledge gaps with regard to assessing the generalizability of in vitro screening methods for assessing the skin sensitizing potential of industrial chemicals.

  7. Solar cells elaborated by chemical methods: examples of research and development at CIE-UNAM

    International Nuclear Information System (INIS)

    Rincon, Marina E.

    2008-01-01

    Full text: At the Energy Research Center (CIE-UNAM-Mexico), the major areas of renewable energy research are solar thermal energy, photovoltaic energy, geothermal energy, hydrogen energy, materials for renewable energy, and energy planning. Among the efforts to developed solar cells, both physical and chemical methods are in progress at CIE-UNAM. In this contribution we focus on the advancement in efficiency, stability, and cost, of photovoltaic junctions based on chemically deposited films. Examples of early research are a composite thin film electrode comprised of SnO2/Bi2S3 nanocrystallites (5 nm) prepared by sequential deposition of SnO2 and Bi2S3 films onto an optically transparent electrode; the co-deposition of pyrrole and Bi2S3 nanoparticles on chemically deposited bismuth sulfide substrates to explore new approaches to improve light-collection efficiency in polymer photovoltaics; the sensitization of titanium dioxide coatings by chemically deposited cadmium selenide and bismuthe sulfide thin films. Here the good photostability of the coatings was promising for the use of the sensitized films in photocatalytic as well as photovoltaic applications. More recently, chemically deposited cadmium sulfide thin films have been explored in planar hybrid heterojunctions with chemically synthesized poly 3-octylthiophene, as well as all-chemically deposited photovoltaic structures. Examples of the last are: chemically deposited thin films of CdS (80 nm), Sb2S3 (450 nm), and Ag2Se (150 nm) annealed at 300 C and integrated into a p-i-n structure glass/SnO2:F/n-CdS/Sb2S3/p-AgSbSe2/Ag, showing Voc ∼ 550 mV and Jsc ∼ 2.3 mA/cm2 at 1 kW/m2 (tungsten halogen) intensity. Similarly, chemically deposited SnS (450nm) and CuS (80nm) thin films integrated in a photovoltaic structure SnO2:F/CdS/SnS/CuS/Ag, showing Voc>300 mV and Jsc up to 5 mA/cm2 under 850 W/m2 tungsten halogen illumination. These photovoltaic structures have been found to be stable over a period extending over

  8. Production of brown algae pyrolysis oils for liquid biofuels depending on the chemical pretreatment methods

    International Nuclear Information System (INIS)

    Choi, Joonhyuk; Choi, Jae-Wook; Suh, Dong Jin; Ha, Jeong-Myeong; Hwang, Ji Won; Jung, Hyun Wook; Lee, Kwan-Young; Woo, Hee-Chul

    2014-01-01

    Highlights: • Pyrolysis of Saccharina japonica, brown algae to produce hydrocarbons. • Sulfuric acid pretreatment of macroalgae to remove inorganic elements. • CaCl 2 treatment of macroalgae to remove valuable fucoidan. • Sulfuric acid pretreatment suppressed the formation of large biochar chunks. • The pretreatment methods allowed the continuous operation of pyrolysis. - Abstract: Based on observations of rapidly growing biochar in fluidization beds, kelp (Saccharina japonica), a species of brown algae, was pretreated for the efficient operation of pyrolysis processes to produce pyrolysis oils. The removal of catalytically active inorganic minerals and the softening of polymeric seaweed structures were performed by means of chemical treatments, including a CaCl 2 treatment to isolate valuable and sticky fucoidan and a sulfuric acid treatment to remove catalytically active minerals. The sulfuric acid pretreatment significantly reduced the inorganic elements but did not significantly affect the properties of the pyrolysis oil compared to the non-treated kelp pyrolysis oil. Whereas the non-treated kelp produced significantly large chunks of biochar, which hindered the continuous operation of pyrolysis, the kelp treated with sulfuric acid did not produce aggregated large particles of biochar, thereby offering a means of developing reliable continuous pyrolysis processes

  9. Evaluation of quantum-chemical methods of radiolysis stability for macromolecular structures

    International Nuclear Information System (INIS)

    Postolache, Cristian; Matei, Lidia

    2005-01-01

    The behavior of macromolecular structures in ionising fields was analyzed by quantum-chemical methods. In this study the primary radiolytic effect was analyzed using a two-step radiolytic mechanism: a) ionisation of molecule and spatial redistribution of atoms in order to reach a minimum value of energy, characteristic to the quantum state; b) neutralisation of the molecule by electron capture and its rapid dissociation into free radicals. Chemical bonds suspected to break are located in the distribution region of LUMO orbital and have minimal homolytic dissociation energies. Representative polymer structures (polyethylene, polypropylene, polystyrene, poly α and β polystyrene, polyisobutylene, polytetrafluoroethylene, poly methylsiloxanes) were analyzed. (authors)

  10. Analysis and classification of physical and chemical methods of fuel activation

    Directory of Open Access Journals (Sweden)

    Fedorchak Viktoriya

    2015-12-01

    Full Text Available The offered article explores various research studies, developed patents in terms of physical and chemical approaches to the activation of fuel. In this regard, national and foreign researches in the field of fuels activators with different principles of action were analysed, evaluating their pros and cons. The article also intends to classify these methods and compare them regarding diverse desired results and types of fuels used. In terms of physical and chemical influences on fuels and the necessity of making constructive changes in the fuel system of internal combustion engines, an optimal approach was outlined.

  11. Antioxidant, Anti-microbial Properties and Chemical Composition of Cumin Essential Oils Extracted by Three Methods

    OpenAIRE

    Fang Lianying; Wang Xiangxing; Guo Limin; Liu Qiang

    2018-01-01

    The purpose of this study is to evaluate the chemical composition, antioxidant and anti-bacterial activity of cumin essential oils (CEOs) extracted by different techniques, including supercritical carbon dioxide extraction (SCE), subcritical butane extraction (SBE) and traditional solvent extraction (SE). Our results indicated that CEOs are a valuable source of bioactive compounds, including cumin aldehyde, γ-terpinene and β-pinene. The most abundant components found in CEOs obtained by SCE a...

  12. Assessing the Applicability of Currently Available Methods for Attributing Foodborne Disease to Sources, Including Food and Food Commodities

    DEFF Research Database (Denmark)

    Pires, Sara Monteiro

    2013-01-01

    on the public health question being addressed, on the data requirements, on advantages and limitations of the method, and on the data availability of the country or region in question. Previous articles have described available methods for source attribution, but have focused only on foodborne microbiological...

  13. In Silico Prediction of Chemicals Binding to Aromatase with Machine Learning Methods.

    Science.gov (United States)

    Du, Hanwen; Cai, Yingchun; Yang, Hongbin; Zhang, Hongxiao; Xue, Yuhan; Liu, Guixia; Tang, Yun; Li, Weihua

    2017-05-15

    Environmental chemicals may affect endocrine systems through multiple mechanisms, one of which is via effects on aromatase (also known as CYP19A1), an enzyme critical for maintaining the normal balance of estrogens and androgens in the body. Therefore, rapid and efficient identification of aromatase-related endocrine disrupting chemicals (EDCs) is important for toxicology and environment risk assessment. In this study, on the basis of the Tox21 10K compound library, in silico classification models for predicting aromatase binders/nonbinders were constructed by machine learning methods. To improve the prediction ability of the models, a combined classifier (CC) strategy that combines different independent machine learning methods was adopted. Performances of the models were measured by test and external validation sets containing 1336 and 216 chemicals, respectively. The best model was obtained with the MACCS (Molecular Access System) fingerprint and CC method, which exhibited an accuracy of 0.84 for the test set and 0.91 for the external validation set. Additionally, several representative substructures for characterizing aromatase binders, such as ketone, lactone, and nitrogen-containing derivatives, were identified using information gain and substructure frequency analysis. Our study provided a systematic assessment of chemicals binding to aromatase. The built models can be helpful to rapidly identify potential EDCs targeting aromatase.

  14. Comparative analysis of chemical similarity methods for modular natural products with a hypothetical structure enumeration algorithm.

    Science.gov (United States)

    Skinnider, Michael A; Dejong, Chris A; Franczak, Brian C; McNicholas, Paul D; Magarvey, Nathan A

    2017-08-16

    Natural products represent a prominent source of pharmaceutically and industrially important agents. Calculating the chemical similarity of two molecules is a central task in cheminformatics, with applications at multiple stages of the drug discovery pipeline. Quantifying the similarity of natural products is a particularly important problem, as the biological activities of these molecules have been extensively optimized by natural selection. The large and structurally complex scaffolds of natural products distinguish their physical and chemical properties from those of synthetic compounds. However, no analysis of the performance of existing methods for molecular similarity calculation specific to natural products has been reported to date. Here, we present LEMONS, an algorithm for the enumeration of hypothetical modular natural product structures. We leverage this algorithm to conduct a comparative analysis of molecular similarity methods within the unique chemical space occupied by modular natural products using controlled synthetic data, and comprehensively investigate the impact of diverse biosynthetic parameters on similarity search. We additionally investigate a recently described algorithm for natural product retrobiosynthesis and alignment, and find that when rule-based retrobiosynthesis can be applied, this approach outperforms conventional two-dimensional fingerprints, suggesting it may represent a valuable approach for the targeted exploration of natural product chemical space and microbial genome mining. Our open-source algorithm is an extensible method of enumerating hypothetical natural product structures with diverse potential applications in bioinformatics.

  15. Development of method to chemical separation of gallium-67 by thermal diffusion technique

    International Nuclear Information System (INIS)

    Martins, Patricia de Andrade

    2012-01-01

    Radioisotopes of gallium have been studied and evaluated for medical applications since 1949. Over the past 50 years 67 Ga has been widely used in the diagnosis of various diseases, including acute and chronic inflammatory lesions, bacterial or sterile and several types of tumors. In Brazil 30% of clinics that provide services for Nuclear Medicine use 67 Ga citrate and the demand for 67 G a at IPEN-CNEN/SP is 37 GBq (1 Ci)/week. The 67 Ga presents physical half-life of 3.26 days (78 hours) and decays 100% by electron capture to stable 67 Zn. Its decay includes the emission of γ rays with energies of 93.3 keV (37%), 184.6 keV (20.4%), 300.2 keV (16.6%) and 888 keV (26%). In the past 67 Ga was produced by the reaction 68 Zn (p, 2n) 67 Ga at IPEN-CNEN/SP. After irradiation, the target was dissolved in concentrated HCl and the solution percolated through a cationic resin DOWEX 50W-X8, 200-400 mesh, conditioned with 10 mol L -1 HCl. Zinc, nickel and copper were eluted in 10 mol L -1 HCl and 67 Ga 3.5 mol L -1 HCl. The final product was obtained as 67 Ga citrate. This work presents a new, fast, direct and efficient method for the chemical separation of 67 G a by thermal diffusion (heating of the target) combined with concentrated acetic acid extraction. Purification was performed by ion exchange chromatography. Natural zinc electrodeposition was performed on nickel/copper plates as substrate and the zinc deposits were adherent to the substrate, slightly shiny and uniform. The targets were irradiated with 26 MeV protons and integrated current of 10 μA.h. After irradiation, the targets were heated at 300 deg C for 2 hours and placed in contact with concentrated acetic acid for 1 hour. The average yield of extraction of 67 Ga was (72 ± 10)%. This solution was evaporated and the residue was taken up in 0.5 mol L -1 NH 4 OH. The 67 G a was purified on cationic resin Dowex 50WX8 in NH 4 OH medium. The 67 Ga recovery was (98 ± 2)%. This solution was evaporated and taken up

  16. In silico prediction of Tetrahymena pyriformis toxicity for diverse industrial chemicals with substructure pattern recognition and machine learning methods.

    Science.gov (United States)

    Cheng, Feixiong; Shen, Jie; Yu, Yue; Li, Weihua; Liu, Guixia; Lee, Philip W; Tang, Yun

    2011-03-01

    There is an increasing need for the rapid safety assessment of chemicals by both industries and regulatory agencies throughout the world. In silico techniques are practical alternatives in the environmental hazard assessment. It is especially true to address the persistence, bioaccumulative and toxicity potentials of organic chemicals. Tetrahymena pyriformis toxicity is often used as a toxic endpoint. In this study, 1571 diverse unique chemicals were collected from the literature and composed of the largest diverse data set for T. pyriformis toxicity. Classification predictive models of T. pyriformis toxicity were developed by substructure pattern recognition and different machine learning methods, including support vector machine (SVM), C4.5 decision tree, k-nearest neighbors and random forest. The results of a 5-fold cross-validation showed that the SVM method performed better than other algorithms. The overall predictive accuracies of the SVM classification model with radial basis functions kernel was 92.2% for the 5-fold cross-validation and 92.6% for the external validation set, respectively. Furthermore, several representative substructure patterns for characterizing T. pyriformis toxicity were also identified via the information gain analysis methods. Copyright © 2010 Elsevier Ltd. All rights reserved.

  17. Solid phase microextraction headspace sampling of chemical warfare agent contaminated samples : method development for GC-MS analysis

    Energy Technology Data Exchange (ETDEWEB)

    Jackson Lepage, C.R.; Hancock, J.R. [Defence Research and Development Canada, Medicine Hat, AB (Canada); Wyatt, H.D.M. [Regina Univ., SK (Canada)

    2004-07-01

    Defence R and D Canada-Suffield (DRDC-Suffield) is responsible for analyzing samples that are suspected to contain chemical warfare agents, either collected by the Canadian Forces or by first-responders in the event of a terrorist attack in Canada. The analytical techniques used to identify the composition of the samples include gas chromatography-mass spectrometry (GC-MS), liquid chromatography-mass spectrometry (LC-MS), Fourier-transform infrared spectroscopy (FT-IR) and nuclear magnetic resonance spectroscopy. GC-MS and LC-MS generally require solvent extraction and reconcentration, thereby increasing sample handling. The authors examined analytical techniques which reduce or eliminate sample manipulation. In particular, this paper presented a screening method based on solid phase microextraction (SPME) headspace sampling and GC-MS analysis for chemical warfare agents such as mustard, sarin, soman, and cyclohexyl methylphosphonofluoridate in contaminated soil samples. SPME is a method which uses small adsorbent polymer coated silica fibers that trap vaporous or liquid analytes for GC or LC analysis. Collection efficiency can be increased by adjusting sampling time and temperature. This method was tested on two real-world samples, one from excavated chemical munitions and the second from a caustic decontamination mixture. 7 refs., 2 tabs., 3 figs.

  18. Combined use of computational chemistry and chemoinformatics methods for chemical discovery

    Energy Technology Data Exchange (ETDEWEB)

    Sugimoto, Manabu, E-mail: sugimoto@kumamoto-u.ac.jp [Graduate School of Science and Technology, Kumamoto University, 2-39-1, Kurokami, Chuo-ku, Kumamoto 860-8555 (Japan); Institute for Molecular Science, 38 Nishigo-Naka, Myodaiji, Okazaki 444-8585 (Japan); CREST, Japan Science and Technology Agency, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012 (Japan); Ideo, Toshihiro; Iwane, Ryo [Graduate School of Science and Technology, Kumamoto University, 2-39-1, Kurokami, Chuo-ku, Kumamoto 860-8555 (Japan)

    2015-12-31

    Data analysis on numerical data by the computational chemistry calculations is carried out to obtain knowledge information of molecules. A molecular database is developed to systematically store chemical, electronic-structure, and knowledge-based information. The database is used to find molecules related to a keyword of “cancer”. Then the electronic-structure calculations are performed to quantitatively evaluate quantum chemical similarity of the molecules. Among the 377 compounds registered in the database, 24 molecules are found to be “cancer”-related. This set of molecules includes both carcinogens and anticancer drugs. The quantum chemical similarity analysis, which is carried out by using numerical results of the density-functional theory calculations, shows that, when some energy spectra are referred to, carcinogens are reasonably distinguished from the anticancer drugs. Therefore these spectral properties are considered of as important measures for classification.

  19. Compositions of graphene materials with metal nanostructures and microstructures and methods of making and using including pressure sensors

    KAUST Repository

    Chen, Ye; Khashab, Niveen M.; Tao, Jing

    2017-01-01

    Composition comprising at least one graphene material and at least one metal. The metal can be in the form of nanoparticles as well as microflakes, including single crystal microflakes. The metal can be intercalated in the graphene sheets

  20. Chemicals of emerging concern in water and bottom sediment in the Great Lakes Basin, 2012: collection methods, analytical methods, quality assurance, and study data

    Science.gov (United States)

    Lee, Kathy E.; Langer, Susan K.; Menheer, Michael A.; Hansen, Donald S.; Foreman, William T.; Furlong, Edward T.; Jorgenson, Zachary G.; Choy, Steven J.; Moore, Jeremy N.; Banda, JoAnn; Gefell, Daniel J.

    2015-01-01

    In synoptic surveys of surface-water quality across the United States, a large group of organic chemicals associated with agricultural, household, and industrial waste have been detected. These chemicals are referred to collectively as chemicals of emerging concern (CECs) and include prescription drugs and antibiotics, over-the-counter medications, reproductive hormones, personal-care products, detergent metabolites, and flame retardants.

  1. Morphological and chemical changes of dentin after applying different sterilization methods

    Directory of Open Access Journals (Sweden)

    Cláudio Antonio Talge Carvalho

    Full Text Available Aim The present study evaluated the morphological and chemical changes of dentin produced by different sterilization methods, using scanning electron microscopy (SEM and energy-dispersive X-ray spectrometry (EDS analysis. Material and method Five human teeth were sectioned into 4 samples, each divided into 3 specimens. The specimens were separated into sterilization groups, as follows: wet heat under pressure; cobalt 60 gamma radiation; and control (without sterilization. After sterilization, the 60 specimens were analyzed by SEM under 3 magnifications: 1500X, 5000X, and 10000X. The images were analyzed by 3 calibrated examiners, who assigned scores according to the changes observed in the dentinal tubules: 0 = no morphological change; 1, 2 and 3 = slight, medium and complete obliteration of the dentinal tubules. The chemical composition of dentin was assessed by EDS, with 15 kV incidence and 1 μm penetration. Result The data obtained were submitted to the statistical tests of Kruskall-Wallis and ANOVA. It was observed that both sterilization methods – with autoclave and with cobalt 60 gamma radiation – produced no significant changes to the morphology of the dentinal tubules or to the chemical composition of dentin. Conclusion Both methods may thus be used to sterilize teeth for research conducted in vitro.

  2. Chemical characteristics of fine particles emitted from different gas cooking methods

    Science.gov (United States)

    See, Siao Wei; Balasubramanian, Rajasekhar

    Gas cooking is an important indoor source of fine particles (PM 2.5). The chemical characteristics of PM 2.5 emitted from different cooking methods, namely, steaming, boiling, stir-frying, pan-frying and deep-frying were investigated in a domestic kitchen. Controlled experiments were conducted to measure the mass concentration of PM 2.5 and its chemical constituents (elemental carbon (EC), organic carbon (OC), polycyclic aromatic hydrocarbons (PAHs), metals and ions) arising from these five cooking methods. To investigate the difference in particle properties of different cooking emissions, the amount and type of food, and the heat setting on the gas stove were kept constant during the entire course of the experiments. Results showed that deep-frying gave rise to the largest amount of PM 2.5 and most chemical components, followed by pan-frying, stir-frying, boiling, and steaming. Oil-based cooking methods released more organic pollutants (OC, PAHs, and organic ions) and metals, while water-based cooking methods accounted for more water-soluble (WS) ions. Their source profiles are also presented and discussed.

  3. Evaluation, including effects of storage and repeated freezing and thawing, of a method for measurement of urinary creatinine

    DEFF Research Database (Denmark)

    Garde, A H; Hansen, Åse Marie; Kristiansen, J

    2003-01-01

    The aims of this study were to elucidate to what extent storage and repeated freezing and thawing influenced the concentration of creatinine in urine samples and to evaluate the method for determination of creatinine in urine. The creatinine method was based on the well-known Jaffe's reaction...... and measured on a COBAS Mira autoanalyser from Roche. The main findings were that samples for analysis of creatinine should be kept at a temperature of -20 degrees C or lower and frozen and thawed only once. The limit of detection, determined as 3 x SD of 20 determinations of a sample at a low concentration (6...

  4. Design of chemical plant

    International Nuclear Information System (INIS)

    Lee, Dong Il; Kim, Seung Jae; Yang, Jae Ho; Ryu, Hwa Won

    1993-01-01

    This book describes design of chemical plant, which includes chemical engineer and plan for chemical plant, development of chemical process, cost engineering pattern, design and process development, general plant construction plan, project engineering, foundation for economy on assets and depreciation, estimation for cost on capital investment and manufacturing cost, design with computers optimal design and method like fluid mechanics design chemical device and estimation for cost, such as dispatch of material and device writing on design report and appendixes.

  5. PM2.5 Chemical Composition at a Rural Background Site in Central Europe, Including Correlation and Air Mass Back Trajectory Analysis.

    Czech Academy of Sciences Publication Activity Database

    Schwarz, Jaroslav; Cusack, Michael; Karban, Jindřich; Chalupníčková, E.; Havránek, Vladimír; Smolík, Jiří; Ždímal, Vladimír

    176-177, JUL 1 (2016), s. 108-120 ISSN 0169-8095 R&D Projects: GA ČR(CZ) GAP209/11/1342; GA MŠk(CZ) LM2011019 EU Projects: European Commission(XE) 262254 - ACTRIS Institutional support: RVO:67985858 ; RVO:61389005 Keywords : rural aerosol * PM2.5 * chemical composition Subject RIV: CF - Physical ; Theoretical Chemistry; BG - Nuclear, Atomic and Molecular Physics, Colliders (UJF-V) Impact factor: 3.778, year: 2016

  6. Standard test methods for chemical, mass spectrometric, spectrochemical, nuclear, and radiochemical analysis of uranium hexafluoride

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2011-01-01

    1.1 These test methods cover procedures for subsampling and for chemical, mass spectrometric, spectrochemical, nuclear, and radiochemical analysis of uranium hexafluoride UF6. Most of these test methods are in routine use to determine conformance to UF6 specifications in the Enrichment and Conversion Facilities. 1.2 The analytical procedures in this document appear in the following order: Note 1—Subcommittee C26.05 will confer with C26.02 concerning the renumbered section in Test Methods C761 to determine how concerns with renumbering these sections, as analytical methods are replaced with stand-alone analytical methods, are best addressed in subsequent publications. Sections Subsampling of Uranium Hexafluoride 7 - 10 Gravimetric Determination of Uranium 11 - 19 Titrimetric Determination of Uranium 20 Preparation of High-Purity U3O 8 21 Isotopic Analysis 22 Isotopic Analysis by Double-Standard Mass-Spectrometer Method 23 - 29 Determination of Hydrocarbons, Chlorocarbons, and Partially Substitut...

  7. Theory of linear physical systems theory of physical systems from the viewpoint of classical dynamics, including Fourier methods

    CERN Document Server

    Guillemin, Ernst A

    2013-01-01

    An eminent electrical engineer and authority on linear system theory presents this advanced treatise, which approaches the subject from the viewpoint of classical dynamics and covers Fourier methods. This volume will assist upper-level undergraduates and graduate students in moving from introductory courses toward an understanding of advanced network synthesis. 1963 edition.

  8. Sighting optics including an optical element having a first focal length and a second focal length and methods for sighting

    Science.gov (United States)

    Crandall, David Lynn

    2011-08-16

    Sighting optics include a front sight and a rear sight positioned in a spaced-apart relation. The rear sight includes an optical element having a first focal length and a second focal length. The first focal length is selected so that it is about equal to a distance separating the optical element and the front sight and the second focal length is selected so that it is about equal to a target distance. The optical element thus brings into simultaneous focus for a user images of the front sight and the target.

  9. Compositions of graphene materials with metal nanostructures and microstructures and methods of making and using including pressure sensors

    KAUST Repository

    Chen, Ye

    2017-01-26

    Composition comprising at least one graphene material and at least one metal. The metal can be in the form of nanoparticles as well as microflakes, including single crystal microflakes. The metal can be intercalated in the graphene sheets. The composition has high conductivity and flexibility. The composition can be made by a one-pot synthesis in which a graphene material precursor is converted to the graphene material, and the metal precursor is converted to the metal. A reducing solvent or dispersant such as NMP can be used. Devices made from the composition include a pressure sensor which has high sensitivity. Two two- dimension materials can be combined to form a hybrid material.

  10. Difference in target definition using three different methods to include respiratory motion in radiotherapy of lung cancer

    DEFF Research Database (Denmark)

    Sloth Møller, Ditte; Knap, Marianne Marquard; Nyeng, Tine Bisballe

    2017-01-01

    : PTVσ yields the smallest volumes but does not ensure coverage of tumor during the full respiratory motion due to tumor deformation. Incorporating the respiratory motion in the delineation (PTVdel) takes into account the entire respiratory cycle including deformation, but at the cost, however, of larger...

  11. Calcium phosphate formation from sea urchin - (brissus latecarinatus via modified mechano-chemical (ultrasonic conversion method

    Directory of Open Access Journals (Sweden)

    R. Samur

    2013-07-01

    Full Text Available This study aims to produce apatite structures, such as hydroxyapatite (HA and fluorapatite (FA, from precursor calcium phosphates of biological origin, namely from sea urchin, with mechano-chemical stirring and hot-plating conversion method. The produced materials were heat treated at 800 °C for 4 hours. X-ray diffraction and scanning electron microscopy (SEM studies were conducted. Calcium phosphate phases were developed. The SEM images showed the formation of micro to nano-powders. The experimental results suggest that sea urchin, Brissus latecarinatus skeleton could be an alternative source for the production of various mono or biphasic calcium phosphates with simple and economic mechano-chemical (ultrasonic conversion method.

  12. 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.

  13. Combined Docking with Classical Force Field and Quantum Chemical Semiempirical Method PM7

    Directory of Open Access Journals (Sweden)

    A. V. Sulimov

    2017-01-01

    Full Text Available Results of the combined use of the classical force field and the recent quantum chemical PM7 method for docking are presented. Initially the gridless docking of a flexible low molecular weight ligand into the rigid target protein is performed with the energy function calculated in the MMFF94 force field with implicit water solvent in the PCM model. Among several hundred thousand local minima, which are found in the docking procedure, about eight thousand lowest energy minima are chosen and then energies of these minima are recalculated with the recent quantum chemical semiempirical PM7 method. This procedure is applied to 16 test complexes with different proteins and ligands. For almost all test complexes such energy recalculation results in the global energy minimum configuration corresponding to the ligand pose near the native ligand position in the crystalized protein-ligand complex. A significant improvement of the ligand positioning accuracy comparing with MMFF94 energy calculations is demonstrated.

  14. Combined Docking with Classical Force Field and Quantum Chemical Semiempirical Method PM7.

    Science.gov (United States)

    Sulimov, A V; Kutov, D C; Katkova, E V; Sulimov, V B

    2017-01-01

    Results of the combined use of the classical force field and the recent quantum chemical PM7 method for docking are presented. Initially the gridless docking of a flexible low molecular weight ligand into the rigid target protein is performed with the energy function calculated in the MMFF94 force field with implicit water solvent in the PCM model. Among several hundred thousand local minima, which are found in the docking procedure, about eight thousand lowest energy minima are chosen and then energies of these minima are recalculated with the recent quantum chemical semiempirical PM7 method. This procedure is applied to 16 test complexes with different proteins and ligands. For almost all test complexes such energy recalculation results in the global energy minimum configuration corresponding to the ligand pose near the native ligand position in the crystalized protein-ligand complex. A significant improvement of the ligand positioning accuracy comparing with MMFF94 energy calculations is demonstrated.

  15. Shining a light on LAMP assays--a comparison of LAMP visualization methods including the novel use of berberine.

    Science.gov (United States)

    Fischbach, Jens; Xander, Nina Carolin; Frohme, Marcus; Glökler, Jörn Felix

    2015-04-01

    The need for simple and effective assays for detecting nucleic acids by isothermal amplification reactions has led to a great variety of end point and real-time monitoring methods. Here we tested direct and indirect methods to visualize the amplification of potato spindle tuber viroid (PSTVd) by loop-mediated isothermal amplification (LAMP) and compared features important for one-pot in-field applications. We compared the performance of magnesium pyrophosphate, hydroxynaphthol blue (HNB), calcein, SYBR Green I, EvaGreen, and berberine. All assays could be used to distinguish between positive and negative samples in visible or UV light. Precipitation of magnesium-pyrophosphate resulted in a turbid reaction solution. The use of HNB resulted in a color change from violet to blue, whereas calcein induced a change from orange to yellow-green. We also investigated berberine as a nucleic acid-specific dye that emits a fluorescence signal under UV light after a positive LAMP reaction. It has a comparable sensitivity to SYBR Green I and EvaGreen. Based on our results, an optimal detection method can be chosen easily for isothermal real-time or end point screening applications.

  16. Measure Guideline: Summary of Interior Ducts in New Construction, Including an Efficient, Affordable Method to Install Fur-Down Interior Ducts

    Energy Technology Data Exchange (ETDEWEB)

    Beal, D. [BA-PIRC, Cocoa, FL (United States); McIlvaine, J. [BA-PIRC, Cocoa, FL (United States); Fonorow, K. [BA-PIRC, Cocoa, FL (United States); Martin, E. [BA-PIRC, Cocoa, FL (United States)

    2011-11-01

    This document illustrates guidelines for the efficient installation of interior duct systems in new housing, including the fur-up chase method, the fur-down chase method, and interior ducts positioned in sealed attics or sealed crawl spaces.

  17. Application of isotopic and chemical methods to the study of hydrological problems in Brazilian northeastern areas

    International Nuclear Information System (INIS)

    Ponte, J.H.

    1979-01-01

    Hydrological studies are reported with samples of ground water from several region of northern - and northeastern Brazil: Marajo Island (State of Para), State of Piaui, Ceara and Rio Grande do Norte. A description is given of the utilization of chemical and isotopic methods, in particular measurements of tritium concentration and 14 C- counting techniques for the determination of the origin and residence time of water. (I.C.R.) [pt

  18. Optical methods for creating delivery systems of chemical compounds to plant roots

    Science.gov (United States)

    Kuznetsov, Pavel E.; Rogacheva, Svetlana M.; Arefeva, Oksana A.; Minin, Dmitryi V.; Tolmachev, Sergey A.; Kupadze, Machammad S.

    2004-08-01

    Spectrophotometric and fluorescence methods have been used for creation and investigation of various systems of target delivery of chemical compounds to roots of plants. The possibility of using liposomes, incrusted by polysaccharides of the external surface of nitrogen-fixing rizospheric bacteria Azospirillum brasilense SP 245, and nanoparticles incrusted by polysaccharides of wheat roots, as the named systems has been shown. The important role of polysaccharide-polysaccharide interaction in the adsorption processes of bacteria on wheat roots has been demonstrated.

  19. 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.

  20. Chemometrics-assisted spectrophotometry method for the determination of chemical oxygen demand in pulping effluent.

    Science.gov (United States)

    Chen, Honglei; Chen, Yuancai; Zhan, Huaiyu; Fu, Shiyu

    2011-04-01

    A new method has been developed for the determination of chemical oxygen demand (COD) in pulping effluent using chemometrics-assisted spectrophotometry. Two calibration models were established by inducing UV-visible spectroscopy (model 1) and derivative spectroscopy (model 2), combined with the chemometrics software Smica-P. Correlation coefficients of the two models are 0.9954 (model 1) and 0.9963 (model 2) when COD of samples is in the range of 0 to 405 mg/L. Sensitivities of the two models are 0.0061 (model 1) and 0.0056 (model 2) and method detection limits are 2.02-2.45 mg/L (model 1) and 2.13-2.51 mg/L (model 2). Validation experiment showed that the average standard deviation of model 2 was 1.11 and that of model 1 was 1.54. Similarly, average relative error of model 2 (4.25%) was lower than model 1 (5.00%), which indicated that the predictability of model 2 was better than that of model 1. Chemometrics-assisted spectrophotometry method did not need chemical reagents and digestion which were required in the conventional methods, and the testing time of the new method was significantly shorter than the conventional ones. The proposed method can be used to measure COD in pulping effluent as an environmentally friendly approach with satisfactory results.

  1. Relative proportions of polycyclic aromatic hydrocarbons differ between accumulation bioassays and chemical methods to predict bioavailability

    Energy Technology Data Exchange (ETDEWEB)

    Gomez-Eyles, Jose L., E-mail: j.l.gomezeyles@reading.ac.u [University of Reading, School of Human and Environmental Sciences, Department of Soil Science, Reading RG6 6DW, Berkshire (United Kingdom); Collins, Chris D.; Hodson, Mark E. [University of Reading, School of Human and Environmental Sciences, Department of Soil Science, Reading RG6 6DW, Berkshire (United Kingdom)

    2010-01-15

    Chemical methods to predict the bioavailable fraction of organic contaminants are usually validated in the literature by comparison with established bioassays. A soil spiked with polycyclic aromatic hydrocarbons (PAHs) was aged over six months and subjected to butanol, cyclodextrin and tenax extractions as well as an exhaustive extraction to determine total PAH concentrations at several time points. Earthworm (Eisenia fetida) and rye grass root (Lolium multiflorum) accumulation bioassays were conducted in parallel. Butanol extractions gave the best relationship with earthworm accumulation (r{sup 2} <= 0.54, p <= 0.01); cyclodextrin, butanol and acetone-hexane extractions all gave good predictions of accumulation in rye grass roots (r{sup 2} <= 0.86, p <= 0.01). However, the profile of the PAHs extracted by the different chemical methods was significantly different (p < 0.01) to that accumulated in the organisms. Biota accumulated a higher proportion of the heavier 4-ringed PAHs. It is concluded that bioaccumulation is a complex process that cannot be predicted by measuring the bioavailable fraction alone. - The ability of chemical methods to predict PAH accumulation in Eisenia fetida and Lolium multiflorum was hindered by the varied metabolic fate of the different PAHs within the organisms.

  2. Numerical investigation of the pulsed NF3 + H2 chemical laser using a model which includes rotational relaxation and semi-classical laser equations

    International Nuclear Information System (INIS)

    Creighton, J.R.

    1975-01-01

    Waveforms and population distributions have been calculated by a numerical model and compared with experiment for an electric-discharge-initiated, pulsed NF 3 + H 2 chemical laser. The model treats each vibrational-rotational state separately, allowing rotational relaxation between adjacent states as well as vibrational relaxation and lasing according to P-branch selection rules. Calculated waveforms agree with experiment and show several features not seen when rotational equilibrium is assumed: simultaneous lasing on many transitions, cascade behavior, spikes due to laser relaxation oscillations, non-Boltzmann rotational distributions, and ''hole burning'' in the population distributions. The calculations give insight into the physical phenomena governing the shape and duration of the waveforms. The effect of varying certain parameters, relaxation rates, temperature, pressure, and diluents, is studied. Best fit to experimental waveforms is obtained when the rotational relaxation rate and collisional line broadening rate are approximately equal at about 10 times the hard sphere collision rate. The IXION computer code, developed for these calculations, is described in detail. In addition, an analytic model is presented which accounts for major features of the total (all transitions) output waveform of the laser assuming rotational equilibrium, a steady state laser model, and constant temperature. A second computer code, MINOTAR, was developed as a general purpose chemical kinetics code. It verifies the analytic model and extends the results to adiabatic reactions where the temperature varies, and can yield waveforms using the assumptions of rotational equilibrium and a steady state laser. The MINOTAR code, being general, can also be used for chemical kinetics problems such as air pollution and combustion

  3. A Quadrature Method of Moments for Polydisperse Flow in Bubble Columns Including Poly-Celerity, Breakup and Coalescence

    Directory of Open Access Journals (Sweden)

    Thomas Acher

    2014-12-01

    Full Text Available A simulation model for 3D polydisperse bubble column flows in an Eulerian/Eulerian framework is presented. A computationally efficient and numerically stable algorithm is created by making use of quadrature method of moments (QMOM functionalities, in conjunction with appropriate breakup and coalescence models. To account for size dependent bubble motion, the constituent moments of the bubble size distribution function are transported with individual velocities. Validation of the simulation results against experimental and numerical data of Hansen [1] show the capability of the present model to accurately predict complex gas-liquid flows.

  4. Chemical and structural properties of Pd nanoparticle-decorated graphene-Electron spectroscopic methods and QUASES

    Czech Academy of Sciences Publication Activity Database

    Lesiak, B.; Jiříček, Petr; Bieloshapka, Igor

    2017-01-01

    Roč. 404, May (2017), s. 300-309 ISSN 0169-4332 R&D Projects: GA MŠk LM2015088 Institutional support: RVO:68378271 Keywords : graphite (Gr) * graphene oxide (GO) * reduced graphene oxide (RGO) * Pd nanoparticles * XPS * QUASES * REELS * chemical and structural properties Subject RIV: BM - Solid Matter Physics ; Magnetism OBOR OECD: Condensed matter physics (including formerly solid state physics, supercond.) Impact factor: 3.387, year: 2016

  5. Apparatus and method for enhanced chemical processing in high pressure and atmospheric plasmas produced by high frequency electromagnetic waves

    Science.gov (United States)

    Efthimion, Philip C.; Helfritch, Dennis J.

    1989-11-28

    An apparatus and method for creating high temperature plasmas for enhanced chemical processing of gaseous fluids, toxic chemicals, and the like, at a wide range of pressures, especially at atmospheric and high pressures includes an electro-magnetic resonator cavity, preferably a reentrant cavity, and a wave guiding structure which connects an electro-magnetic source to the cavity. The cavity includes an intake port and an exhaust port, each having apertures in the conductive walls of the cavity sufficient for the intake of the gaseous fluids and for the discharge of the processed gaseous fluids. The apertures are sufficiently small to prevent the leakage of the electro-magnetic radiation from the cavity. Gaseous fluid flowing from the direction of the electro-magnetic source through the guiding wave structure and into the cavity acts on the plasma to push it away from the guiding wave structure and the electro-magnetic source. The gaseous fluid flow confines the high temperature plasma inside the cavity and allows complete chemical processing of the gaseous fluids at a wide range of pressures.

  6. Principles of cobalt-60 teletherapy including an introduction to the compendium. Guidelines for the documentation of radiation treatment methods

    International Nuclear Information System (INIS)

    Cohen, M.

    1984-01-01

    A great deal of thought has been given in recent years to the documentation of individual patients and their diseases, especially since the computerization of registry sytems facilitates the storage and retrieval of large amounts of data, but the documentation of radiation treatment methods has received surprisingly little attention. The guidelines which follow are intended for use both internally (within radiotherapy centres) and externally when a treatment method is reported in the literature or transferred from one centre to another. The amount of detail reported externally will, of course, depend on the circumstances: for example, a published paper will usually mention only the most important of the radiation and physical parameters, but it is important for the department of origin to list all parameters in a separate document, available on request. These guidelines apply specifically to the documentation of treatment by external radiation beams, although many of the suggestions would also apply to treatment by small sealed sources (brachytherapy) and by unsealed radionuclides. Treatment techniques which involve a combination of external and internal sources (e.g. Ca. cervix uteri treatd by intracavitary sources plus external beam therapy) require particularly careful documentation to indicate the relationship bwtween dose distribution (in both space and time) achieved by the two modalities

  7. Method to Determine Appropriate Source Models of Large Earthquakes Including Tsunami Earthquakes for Tsunami Early Warning in Central America

    Science.gov (United States)

    Tanioka, Yuichiro; Miranda, Greyving Jose Arguello; Gusman, Aditya Riadi; Fujii, Yushiro

    2017-08-01

    Large earthquakes, such as the Mw 7.7 1992 Nicaragua earthquake, have occurred off the Pacific coasts of El Salvador and Nicaragua in Central America and have generated distractive tsunamis along these coasts. It is necessary to determine appropriate fault models before large tsunamis hit the coast. In this study, first, fault parameters were estimated from the W-phase inversion, and then an appropriate fault model was determined from the fault parameters and scaling relationships with a depth dependent rigidity. The method was tested for four large earthquakes, the 1992 Nicaragua tsunami earthquake (Mw7.7), the 2001 El Salvador earthquake (Mw7.7), the 2004 El Astillero earthquake (Mw7.0), and the 2012 El Salvador-Nicaragua earthquake (Mw7.3), which occurred off El Salvador and Nicaragua in Central America. The tsunami numerical simulations were carried out from the determined fault models. We found that the observed tsunami heights, run-up heights, and inundation areas were reasonably well explained by the computed ones. Therefore, our method for tsunami early warning purpose should work to estimate a fault model which reproduces tsunami heights near the coast of El Salvador and Nicaragua due to large earthquakes in the subduction zone.

  8. Innovative Methods for Estimating Densities and Detection Probabilities of Secretive Reptiles Including Invasive Constrictors and Rare Upland Snakes

    Science.gov (United States)

    2018-01-30

    home range  maintenance  or attraction to or avoidance of  landscape features, including  roads  (Morales et al. 2004, McClintock et al. 2012). For example...radiotelemetry and extensive road survey data are used to generate the first density estimates available for the species. The results show that southern...secretive snakes that combines behavioral observations of snake road crossing speed, systematic road survey data, and simulations of spatial

  9. Ion transport by gating voltage to nanopores produced via metal-assisted chemical etching method

    Science.gov (United States)

    Van Toan, Nguyen; Inomata, Naoki; Toda, Masaya; Ono, Takahito

    2018-05-01

    In this work, we report a simple and low-cost way to create nanopores that can be employed for various applications in nanofluidics. Nano sized Ag particles in the range from 1 to 20 nm are formed on a silicon substrate with a de-wetting method. Then the silicon nanopores with an approximate 15 nm average diameter and 200 μm height are successfully produced by the metal-assisted chemical etching method. In addition, electrically driven ion transport in the nanopores is demonstrated for nanofluidic applications. Ion transport through the nanopores is observed and could be controlled by an application of a gating voltage to the nanopores.

  10. Staphylococcus aureus strains associated with food poisoning outbreaks in France: comparison of different molecular typing methods, including MLVA

    Science.gov (United States)

    Roussel, Sophie; Felix, Benjamin; Vingadassalon, Noémie; Grout, Joël; Hennekinne, Jacques-Antoine; Guillier, Laurent; Brisabois, Anne; Auvray, Fréderic

    2015-01-01

    Staphylococcal food poisoning outbreaks (SFPOs) are frequently reported in France. However, most of them remain unconfirmed, highlighting a need for a better characterization of isolated strains. Here we analyzed the genetic diversity of 112 Staphylococcus aureus strains isolated from 76 distinct SFPOs that occurred in France over the last 30 years. We used a recently developed multiple-locus variable-number tandem-repeat analysis (MLVA) protocol and compared this method with pulsed field gel electrophoresis (PFGE), spa-typing and carriage of genes (se genes) coding for 11 staphylococcal enterotoxins (i.e., SEA, SEB, SEC, SED, SEE, SEG, SEH, SEI, SEJ, SEP, SER). The strains known to have an epidemiological association with one another had identical MLVA types, PFGE profiles, spa-types or se gene carriage. MLVA, PFGE and spa-typing divided 103 epidemiologically unrelated strains into 84, 80, and 50 types respectively demonstrating the high genetic diversity of S. aureus strains involved in SFPOs. Each MLVA type shared by more than one strain corresponded to a single spa-type except for one MLVA type represented by four strains that showed two different-but closely related-spa-types. The 87 enterotoxigenic strains were distributed across 68 distinct MLVA types that correlated all with se gene carriage except for four MLVA types. The most frequent se gene detected was sea, followed by seg and sei and the most frequently associated se genes were sea-seh and sea-sed-sej-ser. The discriminatory ability of MLVA was similar to that of PFGE and higher than that of spa-typing. This MLVA protocol was found to be compatible with high throughput analysis, and was also faster and less labor-intensive than PFGE. MLVA holds promise as a suitable method for investigating SFPOs and tracking the source of contamination in food processing facilities in real time. PMID:26441849

  11. Ab initio chemical safety assessment: A workflow based on exposure considerations and non-animal methods.

    Science.gov (United States)

    Berggren, Elisabet; White, Andrew; Ouedraogo, Gladys; Paini, Alicia; Richarz, Andrea-Nicole; Bois, Frederic Y; Exner, Thomas; Leite, Sofia; Grunsven, Leo A van; Worth, Andrew; Mahony, Catherine

    2017-11-01

    We describe and illustrate a workflow for chemical safety assessment that completely avoids animal testing. The workflow, which was developed within the SEURAT-1 initiative, is designed to be applicable to cosmetic ingredients as well as to other types of chemicals, e.g. active ingredients in plant protection products, biocides or pharmaceuticals. The aim of this work was to develop a workflow to assess chemical safety without relying on any animal testing, but instead constructing a hypothesis based on existing data, in silico modelling, biokinetic considerations and then by targeted non-animal testing. For illustrative purposes, we consider a hypothetical new ingredient x as a new component in a body lotion formulation. The workflow is divided into tiers in which points of departure are established through in vitro testing and in silico prediction, as the basis for estimating a safe external dose in a repeated use scenario. The workflow includes a series of possible exit (decision) points, with increasing levels of confidence, based on the sequential application of the Threshold of Toxicological (TTC) approach, read-across, followed by an "ab initio" assessment, in which chemical safety is determined entirely by new in vitro testing and in vitro to in vivo extrapolation by means of mathematical modelling. We believe that this workflow could be applied as a tool to inform targeted and toxicologically relevant in vitro testing, where necessary, and to gain confidence in safety decision making without the need for animal testing.

  12. Testing of the Defense Waste Processing Facility Cold Chemical Dissolution Method in Sludge Batch 9 Qualification

    Energy Technology Data Exchange (ETDEWEB)

    Edwards, T. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Pareizs, J. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Coleman, C. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Young, J. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Brown, L. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2016-05-10

    For each sludge batch that is processed in the Defense Waste Processing Facility (DWPF), the Savannah River National Laboratory (SRNL) tests the applicability of the digestion methods used by the DWPF Laboratory for elemental analysis of Sludge Receipt and Adjustment Tank (SRAT) Receipt samples and SRAT Product process control samples. DWPF SRAT samples are typically dissolved using a method referred to as the DWPF Cold Chemical or Cold Chem Method (CC), (see DWPF Procedure SW4- 15.201). Testing indicates that the CC method produced mixed results. The CC method did not result in complete dissolution of either the SRAT Receipt or SRAT Product with some fine, dark solids remaining. However, elemental analyses did not reveal extreme biases for the major elements in the sludge when compared with analyses obtained following dissolution by hot aqua regia (AR) or sodium peroxide fusion (PF) methods. The CC elemental analyses agreed with the AR and PF methods well enough that it should be adequate for routine process control analyses in the DWPF after much more extensive side-by-side tests of the CC method and the PF method are performed on the first 10 SRAT cycles of the Sludge Batch 9 (SB9) campaign. The DWPF Laboratory should continue with their plans for further tests of the CC method during these 10 SRAT cycles.

  13. A vector/parallel method for a three-dimensional transport model coupled with bio-chemical terms

    NARCIS (Netherlands)

    B.P. Sommeijer (Ben); J. Kok (Jan)

    1995-01-01

    textabstractA so-called fractional step method is considered for the time integration of a three-dimensional transport-chemical model in shallow seas. In this method, the transport part and the chemical part are treated separately by appropriate integration techniques. This separation is motivated

  14. [On necessity to modify biochemical methods for detecting organophosphorus componds in chemical weapons extinction objects (review of literature)].

    Science.gov (United States)

    Prokofieva, D S; Shmurak, V I; Sadovnikov, S V; Gontcharov, N V

    2015-01-01

    The article covers problems of biochemical methods assessing organophosphorus toxic compounds in objects of chemical weapons extinction. The authors present results of works developing new, more specific and selective biochemical methods.

  15. Use of spectrophotometric readout method for free radical dosimetry in radiation processing including low energy electrons and bremsstrahlung

    International Nuclear Information System (INIS)

    Gupta, B.L.

    2000-01-01

    Our laboratory maintains standards for high doses in India. The glutamine powder dosimeter (spectrophotometric readout) is used for this purpose. Present studies show that 20 mg of unirradiated/irradiated glutamine dissolved in freshly prepared 10 ml of aerated aqueous acidic FX solution containing 2 x 10 -3 mol dm -3 ferrous ammonium sulphate and 10 -4 mol dm -3 xylenol orange in 0.033 mol dm -3 sulphuric acid is suitable for the dosimetry in the dose range of 0.1-100 kGy. Normally no corrections are required for the post-irradiation fading of the irradiated glutamine. The response of glutamine dosimeter is independent of irradiation temperature in the range of about 23-30 deg. C and at other temperatures, a correction is necessary. The dose intercomparison results for photon, electron and bremsstrahlung radiations show that glutamine can be used as a reference standard dosimeter. The use of flat polyethylene bags containing glutamine powder has proved very successful for electron dosimetry of wide energies. Several other amino acids like alanine, valine and threonine can also be used to cover wide range of doses using spectrophotometric readout method. (author)

  16. Analysis of alternative transportation methods for radioactive materials shipments including the use of special trains for spent fuel and wastes

    International Nuclear Information System (INIS)

    Smith, D.R.; Luna, R.E.; Taylor, J.M.

    1978-01-01

    Two studies were completed which evaluate the environmental impact of radioactive material transport. The first was a generic study which evaluated all radioactive materials and all transportation modes; the second addressed spent fuel and fuel-cycle wastes shipped by truck, rail and barge. A portion of each of those studies dealing with the change in impact resulting from alternative shipping methods is presented in this paper. Alternatives evaluated in each study were mode shifts, operational constraints, and, in generic case, changes in material properties and package capabilities. Data for the analyses were obtained from a shipper survey and from projections of shipments that would occur in an equilibrium fuel cycle supporting one hundred 1000-MW(e) reactors. Population exposures were deduced from point source radiation formulae using separation distances derived for scenarios appropriate to each shipping mode and to each exposed population group. Fourteen alternatives were investigated for the generic impact case. All showed relatively minor changes in the overall radiological impact. Since the radioactive material transport is estimated to be fewer than 3 latent cancer fatalities (LCF) for each shipment year (compared to some 300,000 yearly cancer fatalities or 5000 LCF's calculated for background radiation using the same radiological effects model), a 15% decrease caused by shifting from passenger air to cargo air is a relatively small effect. Eleven alternatives were considered for the fuel cycle/special train study, but only one produced a reduction in total special train baseline LCF's (.047) that was larger than 5%

  17. State Token Petri Net modeling method for formal verification of computerized procedure including operator's interruptions of procedure execution flow

    International Nuclear Information System (INIS)

    Kim, Yun Goo; Seong, Poong Hyun

    2012-01-01

    The Computerized Procedure System (CPS) is one of the primary operating support systems in the digital Main Control Room. The CPS displays procedure on the computer screen in the form of a flow chart, and displays plant operating information along with procedure instructions. It also supports operator decision making by providing a system decision. A procedure flow should be correct and reliable, as an error would lead to operator misjudgement and inadequate control. In this paper we present a modeling for the CPS that enables formal verification based on Petri nets. The proposed State Token Petri Nets (STPN) also support modeling of a procedure flow that has various interruptions by the operator, according to the plant condition. STPN modeling is compared with Coloured Petri net when they are applied to Emergency Operating Computerized Procedure. A converting program for Computerized Procedure (CP) to STPN has been also developed. The formal verification and validation methods of CP with STPN increase the safety of a nuclear power plant and provide digital quality assurance means that are needed when the role and function of the CPS is increasing.

  18. Age correction in monitoring audiometry: method to update OSHA age-correction tables to include older workers.

    Science.gov (United States)

    Dobie, Robert A; Wojcik, Nancy C

    2015-07-13

    The US Occupational Safety and Health Administration (OSHA) Noise Standard provides the option for employers to apply age corrections to employee audiograms to consider the contribution of ageing when determining whether a standard threshold shift has occurred. Current OSHA age-correction tables are based on 40-year-old data, with small samples and an upper age limit of 60 years. By comparison, recent data (1999-2006) show that hearing thresholds in the US population have improved. Because hearing thresholds have improved, and because older people are increasingly represented in noisy occupations, the OSHA tables no longer represent the current US workforce. This paper presents 2 options for updating the age-correction tables and extending values to age 75 years using recent population-based hearing survey data from the US National Health and Nutrition Examination Survey (NHANES). Both options provide scientifically derived age-correction values that can be easily adopted by OSHA to expand their regulatory guidance to include older workers. Regression analysis was used to derive new age-correction values using audiometric data from the 1999-2006 US NHANES. Using the NHANES median, better-ear thresholds fit to simple polynomial equations, new age-correction values were generated for both men and women for ages 20-75 years. The new age-correction values are presented as 2 options. The preferred option is to replace the current OSHA tables with the values derived from the NHANES median better-ear thresholds for ages 20-75 years. The alternative option is to retain the current OSHA age-correction values up to age 60 years and use the NHANES-based values for ages 61-75 years. Recent NHANES data offer a simple solution to the need for updated, population-based, age-correction tables for OSHA. The options presented here provide scientifically valid and relevant age-correction values which can be easily adopted by OSHA to expand their regulatory guidance to

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

    Directory of Open Access Journals (Sweden)

    Valentina V. Utochnikova

    2012-01-01

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

  20. The advanced CECE process for enriching tritium by the chemical exchange method with a hydrophobic catalyst

    International Nuclear Information System (INIS)

    Kitamoto, Asashi; Shimizu, Masami; Masui, Takashi.

    1992-01-01

    The monothermal chemical exchange process with electrolysis, i.e., CECE process, was an effective method for enriching and removing tritium from tritiated water with low to middle level activity. The purpose of this study is to propose the theoretical background of the two-parameter evaluation method, which is based on a two-step isotope exchange reaction between hydrogen gas and liquid water, for improvement of the performance of a hydrophobic catalyst by a trickle bed-type column. Finally, a two-parameter method could attain the highest performance of isotope separation and the lowest liquid holdup for a trickle bed-type column. Therefore, this method will present some effective and practical procedures in scaling up a tritium enrichment process. The main aspect of the CECE process in engineering design and system evaluation was to develop the isotope exchange column with a high performance catalyst. (author)

  1. Regression Methods for Virtual Metrology of Layer Thickness in Chemical Vapor Deposition

    DEFF Research Database (Denmark)

    Purwins, Hendrik; Barak, Bernd; Nagi, Ahmed

    2014-01-01

    The quality of wafer production in semiconductor manufacturing cannot always be monitored by a costly physical measurement. Instead of measuring a quantity directly, it can be predicted by a regression method (Virtual Metrology). In this paper, a survey on regression methods is given to predict...... average Silicon Nitride cap layer thickness for the Plasma Enhanced Chemical Vapor Deposition (PECVD) dual-layer metal passivation stack process. Process and production equipment Fault Detection and Classification (FDC) data are used as predictor variables. Various variable sets are compared: one most...... algorithm, and Support Vector Regression (SVR). On a test set, SVR outperforms the other methods by a large margin, being more robust towards changes in the production conditions. The method performs better on high-dimensional multivariate input data than on the most predictive variables alone. Process...

  2. Assessment of chromatographic methods for the chemical stability of a new miconazole nitrate cream

    International Nuclear Information System (INIS)

    Garcia Pulpeiro, Oscar; Calzadilla Aguiar, Wendy; Rodriguez Bencomo, Wendy

    2013-01-01

    To assess the chromatographic methods for the chemical stability of a new 2 % miconazol nitrate cream. arious degradation conditions were firstly used in the raw material miconazole nitrate in order to obtain the possible degradation products of this drug and to evaluate them by thin layer chromatography-based method, which was validated to identify the degradation products in the new cream. The performance of the official method based on high resolution liquid chromatography and reported in British Pharmacopoeia 2010 was evaluated, and its selectivity against the possible degradation products were also analyzed. Both chromatographic methods were applied to the analysis of cream samples from the three pilot batches under heat stress for 30 days

  3. Advances in mixed-integer programming methods for chemical production scheduling.

    Science.gov (United States)

    Velez, Sara; Maravelias, Christos T

    2014-01-01

    The goal of this paper is to critically review advances in the area of chemical production scheduling over the past three decades and then present two recently proposed solution methods that have led to dramatic computational enhancements. First, we present a general framework and problem classification and discuss modeling and solution methods with an emphasis on mixed-integer programming (MIP) techniques. Second, we present two solution methods: (a) a constraint propagation algorithm that allows us to compute parameters that are then used to tighten MIP scheduling models and (b) a reformulation that introduces new variables, thus leading to effective branching. We also present computational results and an example illustrating how these methods are implemented, as well as the resulting enhancements. We close with a discussion of open research challenges and future research directions.

  4. Green Jobs: Definition and Method of Appraisal of Chemical and Biological Risks.

    Science.gov (United States)

    Cheneval, Erwan; Busque, Marc-Antoine; Ostiguy, Claude; Lavoie, Jacques; Bourbonnais, Robert; Labrèche, France; Bakhiyi, Bouchra; Zayed, Joseph

    2016-04-01

    In the wake of sustainable development, green jobs are developing rapidly, changing the work environment. However a green job is not automatically a safe job. The aim of the study was to define green jobs, and to establish a preliminary risk assessment of chemical substances and biological agents for workers in Quebec. An operational definition was developed, along with criteria and sustainable development principles to discriminate green jobs from regular jobs. The potential toxicity or hazard associated with their chemical and biological exposures was assessed, and the workers' exposure appraised using an expert assessment method. A control banding approach was then used to assess risks for workers in selected green jobs. A double entry model allowed us to set priorities in terms of chemical or biological risk. Among jobs that present the highest risk potential, several are related to waste management. The developed method is flexible and could be adapted to better appraise the risks that workers are facing or to propose control measures. © The Author 2015. Published by Oxford University Press on behalf of the British Occupational Hygiene Society.

  5. Peculiarities of Enhancing Resistant Starch in Ruminants Using Chemical Methods: Opportunities and Challenges

    Directory of Open Access Journals (Sweden)

    Qendrim Zebeli

    2013-06-01

    Full Text Available High-producing ruminants are fed high amounts of cereal grains, at the expense of dietary fiber, to meet their high energy demands. Grains consist mainly of starch, which is easily degraded in the rumen by microbial glycosidases, providing energy for rapid growth of rumen microbes and short-chain fatty acids (SCFA as the main energy source for the host. Yet, low dietary fiber contents and the rapid accumulation of SCFA lead to rumen disorders in cattle. The chemical processing of grains has become increasingly important to confer their starch resistances against rumen microbial glycosidases, hence generating ruminally resistant starch (RRS. In ruminants, unlike monogastric species, the strategy of enhancing resistant starch is useful, not only in lowering the amount of carbohydrate substrates available for digestion in the upper gut sections, but also in enhancing the net hepatic glucose supply, which can be utilized by the host more efficiently than the hepatic gluconeogenesis of SCFA. The use of chemical methods to enhance the RRS of grains and the feeding of RRS face challenges in the practice; therefore, the present article attempts to summarize the most important achievements in the chemical processing methods used to generate RRS, and review advantages and challenges of feeding RRS to ruminants

  6. Approximate method of calculation of non-equilibrium flow parameters of chemically reacting nitrogen tetroxide in the variable cross-section channels with energy exchange

    International Nuclear Information System (INIS)

    Bazhin, M.A.; Fedosenko, G.Eh.; Shiryaeva, N.M.; Mal'ko, M.V.

    1986-01-01

    It is shown that adiabatic non-equilibrium chemically reacting gas flow with energy exchange in a variable cross-section channel may be subdivided into five possible types: 1) quasi-equilibrium flow; 2) flow in the linear region of deviation from equilibrium state; 3) quasi-frozen flow; 4) flow in the linear region of deviation from frozen state; 5) non-equilibrium flow. Criteria of quasi-equilibrium and quazi-frozen flows, including factors of external action of chemically reacting gas on flow, allow to obtain simple but sufficiently reliable approximate method of calculation of flow parameters. The considered method for solving the problem of chemically reacting nitrogen tetroxide in the variable cross-section channel with energy exchange can be used for evaluation of chemical reaction kinetics on the flow parameter in the stages of axial-flow and radial-flow turbines and in another practical problems

  7. Optimal Control as a method for Diesel engine efficiency assessment including pressure and NO_x constraints

    International Nuclear Information System (INIS)

    Guardiola, Carlos; Climent, Héctor; Pla, Benjamín; Reig, Alberto

    2017-01-01

    Highlights: • Optimal Control is applied for heat release shaping in internal combustion engines. • Optimal Control allows to assess the engine performance with a realistic reference. • The proposed method gives a target heat release law to define control strategies. - Abstract: The present paper studies the optimal heat release law in a Diesel engine to maximise the indicated efficiency subject to different constraints, namely: maximum cylinder pressure, maximum cylinder pressure derivative, and NO_x emission restrictions. With this objective, a simple but also representative model of the combustion process has been implemented. The model consists of a 0D energy balance model aimed to provide the pressure and temperature evolutions in the high pressure loop of the engine thermodynamic cycle from the gas conditions at the intake valve closing and the heat release law. The gas pressure and temperature evolutions allow to compute the engine efficiency and NO_x emissions. The comparison between model and experimental results shows that despite the model simplicity, it is able to reproduce the engine efficiency and NO_x emissions. After the model identification and validation, the optimal control problem is posed and solved by means of Dynamic Programming (DP). Also, if only pressure constraints are considered, the paper proposes a solution that reduces the computation cost of the DP strategy in two orders of magnitude for the case being analysed. The solution provides a target heat release law to define injection strategies but also a more realistic maximum efficiency boundary than the ideal thermodynamic cycles usually employed to estimate the maximum engine efficiency.

  8. Development and validation of NIR-chemometric methods for chemical and pharmaceutical characterization of meloxicam tablets.

    Science.gov (United States)

    Tomuta, Ioan; Iovanov, Rares; Bodoki, Ede; Vonica, Loredana

    2014-04-01

    Near-Infrared (NIR) spectroscopy is an important component of a Process Analytical Technology (PAT) toolbox and is a key technology for enabling the rapid analysis of pharmaceutical tablets. The aim of this research work was to develop and validate NIR-chemometric methods not only for the determination of active pharmaceutical ingredients content but also pharmaceutical properties (crushing strength, disintegration time) of meloxicam tablets. The development of the method for active content assay was performed on samples corresponding to 80%, 90%, 100%, 110% and 120% of meloxicam content and the development of the methods for pharmaceutical characterization was performed on samples prepared at seven different compression forces (ranging from 7 to 45 kN) using NIR transmission spectra of intact tablets and PLS as a regression method. The results show that the developed methods have good trueness, precision and accuracy and are appropriate for direct active content assay in tablets (ranging from 12 to 18 mg/tablet) and also for predicting crushing strength and disintegration time of intact meloxicam tablets. The comparative data show that the proposed methods are in good agreement with the reference methods currently used for the characterization of meloxicam tablets (HPLC-UV methods for the assay and European Pharmacopeia methods for determining the crushing strength and disintegration time). The results show the possibility to predict both chemical properties (active content) and physical/pharmaceutical properties (crushing strength and disintegration time) directly, without any sample preparation, from the same NIR transmission spectrum of meloxicam tablets.

  9. Multiscale approach including microfibril scale to assess elastic constants of cortical bone based on neural network computation and homogenization method.

    Science.gov (United States)

    Barkaoui, Abdelwahed; Chamekh, Abdessalem; Merzouki, Tarek; Hambli, Ridha; Mkaddem, Ali

    2014-03-01

    The complexity and heterogeneity of bone tissue require a multiscale modeling to understand its mechanical behavior and its remodeling mechanisms. In this paper, a novel multiscale hierarchical approach including microfibril scale based on hybrid neural network (NN) computation and homogenization equations was developed to link nanoscopic and macroscopic scales to estimate the elastic properties of human cortical bone. The multiscale model is divided into three main phases: (i) in step 0, the elastic constants of collagen-water and mineral-water composites are calculated by averaging the upper and lower Hill bounds; (ii) in step 1, the elastic properties of the collagen microfibril are computed using a trained NN simulation. Finite element calculation is performed at nanoscopic levels to provide a database to train an in-house NN program; and (iii) in steps 2-10 from fibril to continuum cortical bone tissue, homogenization equations are used to perform the computation at the higher scales. The NN outputs (elastic properties of the microfibril) are used as inputs for the homogenization computation to determine the properties of mineralized collagen fibril. The mechanical and geometrical properties of bone constituents (mineral, collagen, and cross-links) as well as the porosity were taken in consideration. This paper aims to predict analytically the effective elastic constants of cortical bone by modeling its elastic response at these different scales, ranging from the nanostructural to mesostructural levels. Our findings of the lowest scale's output were well integrated with the other higher levels and serve as inputs for the next higher scale modeling. Good agreement was obtained between our predicted results and literature data. Copyright © 2013 John Wiley & Sons, Ltd.

  10. Method and apparatus for enhanced sensitivity filmless medical x-ray imaging, including three-dimensional imaging

    Science.gov (United States)

    Parker, Sherwood

    1995-01-01

    A filmless X-ray imaging system includes at least one X-ray source, upper and lower collimators, and a solid-state detector array, and can provide three-dimensional imaging capability. The X-ray source plane is distance z.sub.1 above upper collimator plane, distance z.sub.2 above the lower collimator plane, and distance z.sub.3 above the plane of the detector array. The object to be X-rayed is located between the upper and lower collimator planes. The upper and lower collimators and the detector array are moved horizontally with scanning velocities v.sub.1, v.sub.2, v.sub.3 proportional to z.sub.1, z.sub.2 and z.sub.3, respectively. The pattern and size of openings in the collimators, and between detector positions is proportional such that similar triangles are always defined relative to the location of the X-ray source. X-rays that pass through openings in the upper collimator will always pass through corresponding and similar openings in the lower collimator, and thence to a corresponding detector in the underlying detector array. Substantially 100% of the X-rays irradiating the object (and neither absorbed nor scattered) pass through the lower collimator openings and are detected, which promotes enhanced sensitivity. A computer system coordinates repositioning of the collimators and detector array, and X-ray source locations. The computer system can store detector array output, and can associate a known X-ray source location with detector array output data, to provide three-dimensional imaging. Detector output may be viewed instantly, stored digitally, and/or transmitted electronically for image viewing at a remote site.

  11. Radiation purification of the chemical industry effluents and possibilities of realization of this method

    International Nuclear Information System (INIS)

    Petryaev, E.P.; Kovalevskaya, A.M.; Shlyk, V.G.; Savushkin, I.A.; Kazazyan, V.T.

    1977-01-01

    Radiation-chemical methods for synthetic fibre industry effluents purification from cyanides, sulphides and monomers, as well as for disinfection of circulation water and improvement in sedimental and filtering properties of waste active slurry in petrochemical industry are described. Chemical plant effluents are purified by 70-90% from cyanides at the dose rate of 0,3 - 0,5 Mrad, by 60 - 70% from sulphides and monomers at the dose of 0,2 Mrad. Circulation water of petroleum processing plant is disinfected at the dose of 0,08 Mrad; the rates of filtration and sedimentation of waste active slurry increase two and three fold, correspondingly, at the dose of 0,6 Mrad. The power of radiation sources required for the industrial realization of radiation purification of liquid wastes has been calculated

  12. EXTRACTION OF ASTAXANTHIN ESTERS FROM SHRIMP WASTE BY CHEMICAL AND MICROBIAL METHODS

    Directory of Open Access Journals (Sweden)

    A. Khanafari, A. Saberi, M. Azar, Gh. Vosooghi, Sh. Jamili, B. Sabbaghzadeh

    2007-04-01

    Full Text Available The carotenoid pigments specifically astaxanthin has many significant applications in food, pharmaceutical and cosmetic industries. The goal of this research was the extraction of Astaxanthin from a certain Persian Gulf shrimp species waste (Penaeus semisulcatus, purification and identification of the pigment by chemical and microbial methods. Microbial fermentation was obtained by inoculation of two Lactobacillus species Lb. plantarum and Lb. acidophilus in the medium culture containing shrimp waste powder by the intervention of lactose sugar, yeast extract, the composition of Both and the coolage (-20oC. The carotenoids were extracted by an organic solvent system. After purification of astaxanthin with the thin layer chromatography method by spectrophotometer, NMR and IR analysis the presence of astaxanthin esters was recognized in this specific species of Persian Gulf shrimp. Results obtained from this study showed that the coolage at –20 oC not only does not have an amplifying effect on the production of astaxanthin but also slightly reduces this effect. Also the effect of intervention of lactose sugar showed more effectiveness in producing astaxanthin than yeast extract or more than with the presence of both. The results also indicated that there is not much difference in the ability of producing the pigment by comparing both Lb. plantarum and Lb. acidophillus. Also results showed the microbial method of extraction of astaxanthin is more effective than chemical method. The pigment extracted from certain amount of shrimp powder, 23.128 mg/g, was calculated.

  13. Overview of a workshop on screening methods for detecting potential (anti-) estrogenic/androgenic chemicals in wildlife

    Science.gov (United States)

    Ankley, Gerald T.; Mihaich, Ellen; Stahl, Ralph G.; Tillitt, Donald E.; Colborn, Theo; McMaster, Suzzanne; Miller, Ron; Bantle, John; Campbell, Pamela; Denslow, Nancy; Dickerson, Richard L.; Folmar, Leroy C.; Fry, Michael; Giesy, John P.; Gray, L. Earl; Guiney, Patrick; Hutchinson, Thomas; Kennedy, Sean W.; Kramer, Vincent; LeBlanc, Gerald A.; Mayes, Monte; Nimrod, Alison; Patino, Reynaldo; Peterson, Richard; Purdy, Richard; Ringer, Robert; Thomas, Peter C.; Touart, Les; Van Der Kraak, Glen; Zacharewski, Tim

    1998-01-01

    The U.S. Congress has passed legislation requiring the U.S. Environmental Protection Agency (U.S. EPA) to develop, validate, and implement screening tests for identifying potential endocrine-disrupting chemicals within 3 years. To aid in the identification of methods suitable for this purpose, the U.S. EPA, the Chemical Manufacturers Association, and the World Wildlife Fund sponsored several workshops, including the present one, which dealt with wildlife species. This workshop was convened with 30 international scientists representing multiple disciplines in March 1997 in Kansas City, Missouri, USA. Participants at the meeting identified methods in terms of their ability to indicate (anti-) estrogenic/androgenic effects, particularly in the context of developmental and reproductive processes. Data derived from structure-activity relationship models and in vitro test systems, although useful in certain contexts, cannot at present replace in vivo tests as the sole basis for screening. A consensus was reached that existing mammalian test methods (e.g., with rats or mice) generally are suitable as screens for assessing potential (anti-) estrogenic/ androgenic effects in mammalian wildlife. However, due to factors such as among-class variation in receptor structure and endocrine function, it is uncertain if these mammalian assays would be of broad utility as screens for other classes of vertebrate wildlife. Existing full and partial life-cycle tests with some avian and fish species could successfully identify chemicals causing endocrine disruption; however, these long-term tests are not suitable for routine screening. However, a number of short-term tests with species from these two classes exist that could serve as effective screening tools for chemicals inducing (anti-) estrogenic/androgenic effects. Existing methods suitable for identifying chemicals with these mechanisms of action in reptiles and amphibians are limited, but in the future, tests with species from

  14. In silico toxicology: comprehensive benchmarking of multi-label classification methods applied to chemical toxicity data

    KAUST Repository

    Raies, Arwa B.

    2017-12-05

    One goal of toxicity testing, among others, is identifying harmful effects of chemicals. Given the high demand for toxicity tests, it is necessary to conduct these tests for multiple toxicity endpoints for the same compound. Current computational toxicology methods aim at developing models mainly to predict a single toxicity endpoint. When chemicals cause several toxicity effects, one model is generated to predict toxicity for each endpoint, which can be labor and computationally intensive when the number of toxicity endpoints is large. Additionally, this approach does not take into consideration possible correlation between the endpoints. Therefore, there has been a recent shift in computational toxicity studies toward generating predictive models able to predict several toxicity endpoints by utilizing correlations between these endpoints. Applying such correlations jointly with compounds\\' features may improve model\\'s performance and reduce the number of required models. This can be achieved through multi-label classification methods. These methods have not undergone comprehensive benchmarking in the domain of predictive toxicology. Therefore, we performed extensive benchmarking and analysis of over 19,000 multi-label classification models generated using combinations of the state-of-the-art methods. The methods have been evaluated from different perspectives using various metrics to assess their effectiveness. We were able to illustrate variability in the performance of the methods under several conditions. This review will help researchers to select the most suitable method for the problem at hand and provide a baseline for evaluating new approaches. Based on this analysis, we provided recommendations for potential future directions in this area.

  15. In silico toxicology: comprehensive benchmarking of multi-label classification methods applied to chemical toxicity data

    KAUST Repository

    Raies, Arwa B.; Bajic, Vladimir B.

    2017-01-01

    One goal of toxicity testing, among others, is identifying harmful effects of chemicals. Given the high demand for toxicity tests, it is necessary to conduct these tests for multiple toxicity endpoints for the same compound. Current computational toxicology methods aim at developing models mainly to predict a single toxicity endpoint. When chemicals cause several toxicity effects, one model is generated to predict toxicity for each endpoint, which can be labor and computationally intensive when the number of toxicity endpoints is large. Additionally, this approach does not take into consideration possible correlation between the endpoints. Therefore, there has been a recent shift in computational toxicity studies toward generating predictive models able to predict several toxicity endpoints by utilizing correlations between these endpoints. Applying such correlations jointly with compounds' features may improve model's performance and reduce the number of required models. This can be achieved through multi-label classification methods. These methods have not undergone comprehensive benchmarking in the domain of predictive toxicology. Therefore, we performed extensive benchmarking and analysis of over 19,000 multi-label classification models generated using combinations of the state-of-the-art methods. The methods have been evaluated from different perspectives using various metrics to assess their effectiveness. We were able to illustrate variability in the performance of the methods under several conditions. This review will help researchers to select the most suitable method for the problem at hand and provide a baseline for evaluating new approaches. Based on this analysis, we provided recommendations for potential future directions in this area.

  16. Results of chemical analysis from the 2008-2009 National Rivers and Streams Assessment Survey, including persistent organic pollutants and pharmaceuticals

    Data.gov (United States)

    U.S. Environmental Protection Agency — In 2008-2009, fish are were collected from approximately 560 national streams, which included a representative subset of 154 urban river sites, which were in close...

  17. The international validation of bio- and chemical-anlaytical screening methods for dioxins and dioxin-like PCBs: the DIFFERENCE project rounds 1 and 2

    NARCIS (Netherlands)

    Loco, van J.; Leeuwen, van S.P.J.; Roos, P.; Carbonnelle, S.; Boer, de J.; Goeyens, L.; Beernaert, H.

    2004-01-01

    The European research project DIFFERENCE is focussed on the development, optimisation and validation of screening methods for dioxin analysis, including bio-analytical and chemical techniques (CALUX, GC-LRMS/MS, GC x GC-ECD) and on the optimisation and validation of new extraction and clean-up

  18. The Synthesis and Characterization of W- 1wt.% TiC Alloy Using a Chemical Method

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Taehee; Ryu, Ho Jin [KAIST, Daejeon (Korea, Republic of)

    2016-10-15

    The tungsten and its alloys have been used in many applications due to their excellent mechanical and thermal properties such as high melting point, high thermal conductivity, high strength at elevated temperatures, low sputtering yield in radiation environment and low tritium inventory. Moreover, many researchers consider tungsten alloys as the most promising candidate for plasma facing components for future nuclear fusion reactors. Three samples of W – 1.0 wt.% TiC composites with the different fabrication methods were successfully developed. The combined method of the wet chemical method and 3D mixing showed small amount of agglomeration of TiC particles, however, the TiC particle sizes were smaller than 3DM1 sample. Since the WCM1 showed the better mechanical property, microhardness, the main future plan is to achieve the same or improved mechanical property of W3D1.

  19. Recycling and Resistance of Petrogenic Particulate Organic Carbon: Implications from A Chemical Oxidation Method

    Science.gov (United States)

    Zhang, T.; Li, G.; Ji, J.

    2013-12-01

    Petrogenic particulate organic carbon (OCpetro) represents a small fraction of photosynthetic carbon which escapes pedogenic-petrogenic degradation and gets trapped in the lithosphere. Exhumation and recycling of OCpetro are of significant importance in the global carbon cycle because OCpetro oxidation represents a substantial carbon source to the atmosphere while the re-burial of OCpetro in sediment deposits has no net effect. Though studies have investigated various behaviors of OCpetro in the surface environments (e.g., riverine mobilization, marine deposition, and microbial remineralization), less attention has been paid to the reaction kinetics and structural transformations during OCpetro oxidation. Here we assess the OCpetro-oxidation process based on a chemical oxidation method adopted from soil studies. The employed chemical oxidation method is considered an effective simulation of natural oxidation in highly oxidative environments, and has been widely used in soil studies to isolate the inert soil carbon pool. We applied this chemical method to the OCpetro-enriched black shale samples from the middle-lower Yangtze (Changjiang) basin, China, and performed comprehensive instrumental analyses (element analysis, Fourier transform infrared (FTIR) spectrum, and Raman spectrum). We also conducted step-oxidizing experiments following fixed time series and monitored the reaction process in rigorously controlled lab conditions. In this work, we present our experiment results and discuss the implications for the recycling and properties of OCpetro. Particulate organic carbon concentration of black shale samples before and after oxidation helps to quantify the oxidability of OCpetro and constrain the preservation efficiency of OCpetro during fluvial erosion over large river basin scales. FTIR and Raman analyses reveal clear structural variations on atomic and molecular levels. Results from the step-oxidizing experiments provide detailed information about the reaction

  20. Comparison of wet-chemical methods for determination of lipid hydroperoxides

    DEFF Research Database (Denmark)

    Nielsen, Nina Skall; Timm Heinrich, Maike; Jacobsen, Charlotte

    2003-01-01

    Five methods for determination of lipid hydroperoxides were evaluated, including two iodometric procedures involving a titration and a spectrophotometric micro method, and three other spectrophotometric methods namely the ferro, International Dairy Federation (IDF) and FOX2 (ferrous oxidation...... in xylenol orange). Peroxide values determined in a range of food products by these five methods gave different results. The ferro method required large amounts of solvent (50 mL/sample); the FOX2 method had a low range (0.005-0.04 mumol hydroperoxide); the end point detection of the titration method...... was subjective and required a large amount of sample (1 g); and the micro method was sensitive to interruptions during execution. Therefore, only the modified IDF method was chosen for further testing and validation. Stability tests of the standard curve showed a variation coefficient of 4% and within runs...

  1. Chemical kinetics of gas reactions

    CERN Document Server

    Kondrat'Ev, V N

    2013-01-01

    Chemical Kinetics of Gas Reactions explores the advances in gas kinetics and thermal, photochemical, electrical discharge, and radiation chemical reactions. This book is composed of 10 chapters, and begins with the presentation of general kinetic rules for simple and complex chemical reactions. The next chapters deal with the experimental methods for evaluating chemical reaction mechanisms and some theories of elementary chemical processes. These topics are followed by discussions on certain class of chemical reactions, including unimolecular, bimolecular, and termolecular reactions. The rema

  2. PbO networks composed of single crystalline nanosheets synthesized by a facile chemical precipitation method

    Energy Technology Data Exchange (ETDEWEB)

    Samberg, Joshua P. [Department of Materials Science and Engineering, North Carolina State University, 911 Partners Way, Engineering Building I, Raleigh, NC 27695-7907 (United States); Kajbafvala, Amir, E-mail: amir.kajbafvala@gmail.com [Department of Materials Science and Engineering, North Carolina State University, 911 Partners Way, Engineering Building I, Raleigh, NC 27695-7907 (United States); Koolivand, Amir [Department of Chemistry, North Carolina State University, 2620 Yarbrough Drive, Raleigh, NC 27695 (United States)

    2014-03-01

    Graphical abstract: - Highlights: • Synthesis of PbO networks through a simple chemical precipitation route. • The synthesis method is rapid and low-cost. • Each network is composed of single crystalline PbO nanosheets. • A possible growth mechanism is proposed for synthesized PbO networks. - Abstract: For the field of energy storage, nanostructured lead oxide (PbO) shows immense potential for increased specific energy and deep discharge for lead acid battery technologies. In this work, PbO networks composed of single crystalline nanosheets were synthesized utilizing a simple, low cost and rapid chemical precipitation method. The PbO networks were prepared in a single reaction vessel from starting reagents of lead acetate dehydrate, ammonium hydroxide and deionized water. Lead acetate dehydrate was chosen as a reagent, as opposed to lead nitrate, to eliminate the possibility of nitrate contamination of the final product. X-ray diffraction (XRD) analysis, high resolution scanning electron microscopy (HRSEM) and high resolution transmission electron microscopy (HRTEM) analysis were used to characterize the synthesized PbO networks. The reproducible method described herein synthesized pure β-PbO (massicot) powders, with no byproducts. A possible formation mechanism for these PbO networks is proposed. The growth is found to proceed predominately in the 〈1 1 1〉 and 〈2 0 0〉 directions while being limited in the 〈0 1 1〉 direction.

  3. PbO networks composed of single crystalline nanosheets synthesized by a facile chemical precipitation method

    International Nuclear Information System (INIS)

    Samberg, Joshua P.; Kajbafvala, Amir; Koolivand, Amir

    2014-01-01

    Graphical abstract: - Highlights: • Synthesis of PbO networks through a simple chemical precipitation route. • The synthesis method is rapid and low-cost. • Each network is composed of single crystalline PbO nanosheets. • A possible growth mechanism is proposed for synthesized PbO networks. - Abstract: For the field of energy storage, nanostructured lead oxide (PbO) shows immense potential for increased specific energy and deep discharge for lead acid battery technologies. In this work, PbO networks composed of single crystalline nanosheets were synthesized utilizing a simple, low cost and rapid chemical precipitation method. The PbO networks were prepared in a single reaction vessel from starting reagents of lead acetate dehydrate, ammonium hydroxide and deionized water. Lead acetate dehydrate was chosen as a reagent, as opposed to lead nitrate, to eliminate the possibility of nitrate contamination of the final product. X-ray diffraction (XRD) analysis, high resolution scanning electron microscopy (HRSEM) and high resolution transmission electron microscopy (HRTEM) analysis were used to characterize the synthesized PbO networks. The reproducible method described herein synthesized pure β-PbO (massicot) powders, with no byproducts. A possible formation mechanism for these PbO networks is proposed. The growth is found to proceed predominately in the 〈1 1 1〉 and 〈2 0 0〉 directions while being limited in the 〈0 1 1〉 direction

  4. U-Pb dating by zircon dissolution method using chemical abrasion

    Energy Technology Data Exchange (ETDEWEB)

    Takehara, Lucy, E-mail: lucytakehara@gmail.com.br [Servico Geologico do Brasil (CPRM), Brasilia, DF (Brazil); Chemale Junior, Farid [Universidade de Brasilia (UnB), Brasilia, DF (Brazil). Inst. de Geociencias. Lab. de Geocronologia; Hartmann, Leo A. [Universidade Federal do Rio Grande do Sul (UFRS), Porto Alegre, RS (Brazil). Inst. de Geociencias; Dussin, Ivo A.; Kawashita, Koji [Universidade de Sao Paulo (USP), SP, (Brazil). Centro de Pesquisa Geocronologicas

    2012-06-15

    Chemical abrasion was carried out on zircons grains of the Temora II standard for U-Pb dating prior to analyses using in situ Laser Ablation-Multi Collector Ion Coupled Plasma Mass Spectrometer (LA-ICPMS) followed by the Isotope Dissolution Thermal Ionization Mass Spectrometer (ID-TIMS) method. The proposed methodology was herein applied in order to reduce primarily the effects of secondary Pb loss, the presence of common lead and/or silicate impurities. Nine Temora II zircon grains were analyzed by the laser ablation method yielding an age of 418.3 +- 4.3 Ma. Zircon grains of a same population were separated for chemical abrasion before dissolution and mass spectrometry analyses. Six fractions of them were separated for isotope dissolution using {sup 235}U-{sup 205}Pb mixed spike after we have checked and assured the laboratory conditions of low blank values for total Pb of less than 2 pg/g. The obtained U-Pb zircon age by the ID-TIMS method was 415.7 +- 1.8 Ma (error 0.43 %) based on four successful determinations. The results are consistent with the published ages for the Temora diorite (Temora I - 416.75 +- 1.3 Ma; Temora II - 416.78 +- 0.33 Ma) and established as 416 +- 0.33 Ma. The technique is thus recommended for high precision U-Pb zircon analyses (error < 1 %), mainly for high resolution stratigraphic studies of Phanerozoic sequences. (author)

  5. Characterization of Olive Oil by Ultrasonic and Physico-chemical Methods

    Science.gov (United States)

    Alouache, B.; Khechena, F. K.; Lecheb, F.; Boutkedjirt, T.

    Olive oil excels by its nutritional and medicinal benefits. It can be consumed without any treatment. However, its quality can be altered by inadequate storage conditions or if it is mixed with other kinds of oils. The objective of this work is to demonstrate the ability of ultrasonic methods to characterize and control olive oil quality. By using of a transducer of 2.25 MHz nominal frequency, in pulse echo mode, ultrasonic parameters, such as propagation velocity and attenuation,have been measured for pure olive oil and for its mixtures with sunflower oil at different proportions. Mechanical properties, such as density and viscosity, have also been determined. The results of ultrasonic measurements are consistent with those obtained by physico-chemical methods, such as rancidity degree, acid index, UV specific extinction coefficient and viscosity. They show that the ultrasonic method allows to distinguish between mixtures at different proportions. The study allows concluding that ultrasound techniques can be considered as a useful complement to existing physico-chemical analysis techniques.

  6. Comparison of Three Sample Preparation Methods for Analysis of Chemical Warfare Agent Stimulants in Water

    International Nuclear Information System (INIS)

    Alessandro Sassolini

    2015-01-01

    Analytical chemistry in CBRNe (Chemical Biological Radiological Nuclear explosive) context requires not only high quality data; quickness, ruggedness and robustness are also mandatory. In this work, three samples preparation methods were compared using several organophosphorus pesticides as test compounds, used as stimulants of nerve CWA (Chemical Warfare Agents) to choose the one with best characteristics. Result was obtained better with the Dispersive Liquid-Liquid Micro Extraction (DLLME), relatively new in CBRNe field, obtaining uncertainty for different simulants between 8 and 15 % while a quantification limit between 0.01 and 0.08 μg/ l. To optimize this extraction method, different organo chlorinated solvents also tested but not relevant difference in these tests was obtained. In this work, all samples were analyzed by using a gas chromatography coupled with mass spectrometer (GC-MS) and also with Gas Chromatograph coupled with Nitrogen Phosphorous Detector (NPD) for DLLME samples to evaluate a low cost and rugged instrument adapt to field analytical methods with good performance in terms of uncertainty and sensibility even if poorer respect to the mass spectrometry. (author)

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

    Science.gov (United States)

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

    2012-01-01

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

  8. A high-throughput method for assessing chemical toxicity using a Caenorhabditis elegans reproduction assay

    International Nuclear Information System (INIS)

    Boyd, Windy A.; McBride, Sandra J.; Rice, Julie R.; Snyder, Daniel W.; Freedman, Jonathan H.

    2010-01-01

    The National Research Council has outlined the need for non-mammalian toxicological models to test the potential health effects of a large number of chemicals while also reducing the use of traditional animal models. The nematode Caenorhabditis elegans is an attractive alternative model because of its well-characterized and evolutionarily conserved biology, low cost, and ability to be used in high-throughput screening. A high-throughput method is described for quantifying the reproductive capacity of C. elegans exposed to chemicals for 48 h from the last larval stage (L4) to adulthood using a COPAS Biosort. Initially, the effects of exposure conditions that could influence reproduction were defined. Concentrations of DMSO vehicle ≤ 1% did not affect reproduction. Previous studies indicated that C. elegans may be influenced by exposure to low pH conditions. At pHs greater than 4.5, C. elegans reproduction was not affected; however below this pH there was a significant decrease in the number of offspring. Cadmium chloride was chosen as a model toxicant to verify that automated measurements were comparable to those of traditional observational studies. EC 50 values for cadmium for automated measurements (176-192 μM) were comparable to those previously reported for a 72-h exposure using manual counting (151 μM). The toxicity of seven test toxicants on C. elegans reproduction was highly correlative with rodent lethality suggesting that this assay may be useful in predicting the potential toxicity of chemicals in other organisms.

  9. Structure activity studies of an analgesic drug tapentadol hydrochloride by spectroscopic and quantum chemical methods

    Science.gov (United States)

    Arjunan, V.; Santhanam, R.; Marchewka, M. K.; Mohan, S.; Yang, Haifeng

    2015-11-01

    Tapentadol is a novel opioid pain reliever drug with a dual mechanism of action, having potency between morphine and tramadol. Quantum chemical calculations have been carried out for tapentadol hydrochloride (TAP.Cl) to determine the properties. The geometry is optimised and the structural properties of the compound were determined from the optimised geometry by B3LYP method using 6-311++G(d,p), 6-31G(d,p) and cc-pVDZ basis sets. FT-IR and FT-Raman spectra are recorded in the solid phase in the region of 4000-400 and 4000-100 cm-1, respectively. Frontier molecular orbital energies, LUMO-HOMO energy gap, ionisation potential, electron affinity, electronegativity, hardness and chemical potential are also calculated. The stability of the molecule arising from hyperconjugative interactions and charge delocalisation has been analysed using NBO analysis. The 1H and 13C nuclear magnetic resonance chemical shifts of the molecule are analysed.

  10. A path flux analysis method for the reduction of detailed chemical kinetic mechanisms

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Wenting; Ju, Yiguang [Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, NJ 08544 (United States); Chen, Zheng [State Key Laboratory for Turbulence and Complex Systems, College of Engineering, Peking University, Beijing 100871 (China); Gou, Xiaolong [School of Power Engineering, Chongqing University, Chongqing 400044 (China)

    2010-07-15

    A direct path flux analysis (PFA) method for kinetic mechanism reduction is proposed and validated by using high temperature ignition, perfect stirred reactors, and steady and unsteady flame propagations of n-heptane and n-decane/air mixtures. The formation and consumption fluxes of each species at multiple reaction path generations are analyzed and used to identify the important reaction pathways and the associated species. The formation and consumption path fluxes used in this method retain flux conservation information and are used to define the path indexes for the first and the second generation reaction paths related to a targeted species. Based on the indexes of each reaction path for the first and second generations, different sized reduced chemical mechanisms which contain different number of species are generated. The reduced mechanisms of n-heptane and n-decane obtained by using the present method are compared to those generated by the direct relation graph (DRG) method. The reaction path analysis for n-decane is conducted to demonstrate the validity of the present method. The comparisons of the ignition delay times, flame propagation speeds, flame structures, and unsteady spherical flame propagation processes showed that with either the same or significantly less number of species, the reduced mechanisms generated by the present PFA are more accurate than that of DRG in a broad range of initial pressures and temperatures. The method is also integrated with the dynamic multi-timescale method and a further increase of computation efficiency is achieved. (author)

  11. A rapid chemical method for lysing Arabidopsis cells for protein analysis

    Directory of Open Access Journals (Sweden)

    Takano Tetsuo

    2011-07-01

    Full Text Available Abstract Background Protein extraction is a frequent procedure in biological research. For preparation of plant cell extracts, plant materials usually have to be ground and homogenized to physically break the robust cell wall, but this step is laborious and time-consuming when a large number of samples are handled at once. Results We developed a chemical method for lysing Arabidopsis cells without grinding. In this method, plants are boiled for just 10 minutes in a solution containing a Ca2+ chelator and detergent. Cell extracts prepared by this method were suitable for SDS-PAGE and immunoblot analysis. This method was also applicable to genomic DNA extraction for PCR analysis. Our method was applied to many other plant species, and worked well for some of them. Conclusions Our method is rapid and economical, and allows many samples to be prepared simultaneously for protein analysis. Our method is useful not only for Arabidopsis research but also research on certain other species.

  12. Recovery of Americium-241 from lightning rod by the method of chemical treatment

    International Nuclear Information System (INIS)

    Cruz, W.H.

    2013-01-01

    About 95% of the lightning rods installed in the Peruvian territory have set in their structures, pose small amounts of radioactive sources such as Americium-241 ( 241 Am), fewer and Radium 226 ( 226 Ra) these are alpha emitters and have a half life of 432 years and 1600 years respectively. In this paper describes the recovery of radioactive sources of 241 Am radioactive lightning rods using the conventional chemical treatment method using agents and acids to break down the slides. The 241 Am recovered was as excitation source and alpha particle generator for analysing samples by X Ray Fluorescence, for fixing the stainless steel 241 Am technique was used electrodeposition. (author)

  13. ELECTROREDUCTION MECHANISM OF Ni(DMG)-2 COMPLEX STUDIED WITH QUANTUM CHEMICAL METHOD

    Institute of Scientific and Technical Information of China (English)

    倪亚明; 任镜清; 黎健; 王德民; 梁伟根; 朱芝仙; 高小霞

    1990-01-01

    The electronic structures of the species Ni(DMG)2, (Ni(DMG)2)- and (Ni(DMG)2)2- have been studied by INDO quantum chemical method. The results have clearly shown that in the first stage of the electroreduction of Ni(DMG)2, one electron interacts with the d orbitals on the nickel atom, while in the further stage the second electron interacts with the p orbitals on the nitrogen atoms. It conforms with our electrochemical experimental studies which showed that not only Ni(Ⅱ) is reduced but also DMG is catalytically reduced during the reduction of Ni(DMG)2.

  14. Evaluation of improved chemical waste disposal and recovery methods for N reactor fuel fabrication operations: 1984 annual report

    International Nuclear Information System (INIS)

    Stewart, T.L.; Hartley, J.N.

    1984-12-01

    Pacific Northwest Laboratory personnel identified and evaluated alternative methods for recovery, recycle, and disposal of waste acids produced during N Reactor fuel operations. This work was conducted under a program sponsored by UNC Nuclear Industries, Inc.; the program goals were to reduce the volume of liquid waste by rejuvenating and recycling acid solutions and to generate a residual waste low in nitrates, fluorides, and metals. Disposal methods under consideration included nitric acid reclamation, grout encapsulation of final residual waste, nitrogen fertilizer production, biodenitrifaction, chemical or thermal destruction of NO 3 , and short-term impoundment of liquid NO 3 /SO 4 wastes. Preliminary testing indicated that the most feasible and practicable of these alternatives were (1) nitric acid reclamation followed by grouting of residual waste and (2) nitrogen fertilizer production. This report summarizes the investigations, findings, and recommendations for the 1984 fiscal year

  15. TALOS+: a hybrid method for predicting protein backbone torsion angles from NMR chemical shifts

    Energy Technology Data Exchange (ETDEWEB)

    Shen Yang; Delaglio, Frank [National Institutes of Health, Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases (United States); Cornilescu, Gabriel [National Magnetic Resonance Facility (United States); Bax, Ad [National Institutes of Health, Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases (United States)], E-mail: bax@nih.gov

    2009-08-15

    NMR chemical shifts in proteins depend strongly on local structure. The program TALOS establishes an empirical relation between {sup 13}C, {sup 15}N and {sup 1}H chemical shifts and backbone torsion angles {phi} and {psi} (Cornilescu et al. J Biomol NMR 13 289-302, 1999). Extension of the original 20-protein database to 200 proteins increased the fraction of residues for which backbone angles could be predicted from 65 to 74%, while reducing the error rate from 3 to 2.5%. Addition of a two-layer neural network filter to the database fragment selection process forms the basis for a new program, TALOS+, which further enhances the prediction rate to 88.5%, without increasing the error rate. Excluding the 2.5% of residues for which TALOS+ makes predictions that strongly differ from those observed in the crystalline state, the accuracy of predicted {phi} and {psi} angles, equals {+-}13{sup o}. Large discrepancies between predictions and crystal structures are primarily limited to loop regions, and for the few cases where multiple X-ray structures are available such residues are often found in different states in the different structures. The TALOS+ output includes predictions for individual residues with missing chemical shifts, and the neural network component of the program also predicts secondary structure with good accuracy.

  16. Saskatchewan resources. [including uranium

    Energy Technology Data Exchange (ETDEWEB)

    1979-09-01

    The production of chemicals and minerals for the chemical industry in Saskatchewan are featured, with some discussion of resource taxation. The commodities mentioned include potash, fatty amines, uranium, heavy oil, sodium sulfate, chlorine, sodium hydroxide, sodium chlorate and bentonite. Following the successful outcome of the Cluff Lake inquiry, the uranium industry is booming. Some developments and production figures for Gulf Minerals, Amok, Cenex and Eldorado are mentioned.

  17. Biomimetic hydrophobic surface fabricated by chemical etching method from hierarchically structured magnesium alloy substrate

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Yan; Yin, Xiaoming; Zhang, Jijia [Key Laboratory of Bionic Engineering (Ministry of Education), Jilin University, Changchun 130022 (China); Wang, Yaming [Institute for Advanced Ceramics, Harbin Institute of Technology, Harbin 150001 (China); Han, Zhiwu, E-mail: zwhan@jlu.edu.cn [Key Laboratory of Bionic Engineering (Ministry of Education), Jilin University, Changchun 130022 (China); Ren, Luquan [Key Laboratory of Bionic Engineering (Ministry of Education), Jilin University, Changchun 130022 (China)

    2013-09-01

    As one of the lightest metal materials, magnesium alloy plays an important role in industry such as automobile, airplane and electronic product. However, magnesium alloy is hindered due to its high chemical activity and easily corroded. Here, inspired by typical plant surfaces such as lotus leaves and petals of red rose with super-hydrophobic character, the new hydrophobic surface is fabricated on magnesium alloy to improve anti-corrosion by two-step methodology. The procedure is that the samples are processed by laser first and then immersed and etched in the aqueous AgNO{sub 3} solution concentrations of 0.1 mol/L, 0.3 mol/L and 0.5 mol/L for different times of 15 s, 40 s and 60 s, respectively, finally modified by DTS (CH{sub 3}(CH{sub 2}){sub 11}Si(OCH{sub 3}){sub 3}). The microstructure, chemical composition, wettability and anti-corrosion are characterized by means of SEM, XPS, water contact angle measurement and electrochemical method. The hydrophobic surfaces with microscale crater-like and nanoscale flower-like binary structure are obtained. The low-energy material is contained in surface after DTS treatment. The contact angles could reach up to 138.4 ± 2°, which hydrophobic property is both related to the micro–nano binary structure and chemical composition. The results of electrochemical measurements show that anti-corrosion property of magnesium alloy is improved. Furthermore, our research is expected to create some ideas from natural enlightenment to improve anti-corrosion property of magnesium alloy while this method can be easily extended to other metal materials.

  18. A Parallel Multiblock Structured Grid Method with Automated Interblocked Unstructured Grids for Chemically Reacting Flows

    Science.gov (United States)

    Spiegel, Seth Christian

    An automated method for using unstructured grids to patch non- C0 interfaces between structured blocks has been developed in conjunction with a finite-volume method for solving chemically reacting flows on unstructured grids. Although the standalone unstructured solver, FVFLO-NCSU, is capable of resolving flows for high-speed aeropropulsion devices with complex geometries, unstructured-mesh algorithms are inherently inefficient when compared to their structured counterparts. However, the advantages of structured algorithms in developing a flow solution in a timely manner can be negated by the amount of time required to develop a mesh for complex geometries. The global domain can be split up into numerous smaller blocks during the grid-generation process to alleviate some of the difficulties in creating these complex meshes. An even greater abatement can be found by allowing the nodes on abutting block interfaces to be nonmatching or non-C 0 continuous. One code capable of solving chemically reacting flows on these multiblock grids is VULCAN, which uses a nonconservative approach for patching non-C0 block interfaces. The developed automated unstructured-grid patching algorithm has been installed within VULCAN to provide it the capability of a fully conservative approach for patching non-C0 block interfaces. Additionally, the FVFLO-NCSU solver algorithms have been deeply intertwined with the VULCAN source code to solve chemically reacting flows on these unstructured patches. Finally, the CGNS software library was added to the VULCAN postprocessor so structured and unstructured data can be stored in a single compact file. This final upgrade to VULCAN has been successfully installed and verified using test cases with particular interest towards those involving grids with non- C0 block interfaces.

  19. Signal transduction profile of chemical sensitisers in dendritic cells: An endpoint to be included in a cell-based in vitro alternative approach to hazard identification?

    International Nuclear Information System (INIS)

    Neves, Bruno Miguel; Goncalo, Margarida; Figueiredo, Americo; Duarte, Carlos B.; Lopes, Maria Celeste; Cruz, Maria Teresa

    2011-01-01

    The development of non-animal testing methods for the assessment of skin sensitisation potential is an urgent challenge within the framework of existing and forthcoming legislation. Efforts have been made to replace current animal tests, but so far no alternative methods have been developed. It is widely recognised that alternatives to animal testing cannot be accomplished with a single approach, but rather will require the integration of results obtained from different in vitro and in silico assays. The argument subjacent to the development of in vitro dendritic cell (DC)-based assays is that sensitiser-induced changes in the DC phenotype can be differentiated from those induced by irritants. This assumption is derived from the unique capacity of DC to convert environmental signals encountered at the skin into a receptor expression pattern (MHC class II molecules, co-stimulatory molecules, chemokine receptors) and a soluble mediator release profile that will stimulate T lymphocytes. Since signal transduction cascades precede changes in surface marker expression and cytokine/chemokine secretion, these phenotypic modifications are a consequence of a signal transduction profile that is specifically triggered by sensitisers and not by irritants. A limited number of studies have addressed this subject and the present review attempts to summarise and highlight all of the signalling pathways modulated by skin sensitisers and irritants. Furthermore, we conclude this review by focusing on the most promising strategies suitable for inclusion into a cell-based in vitro alternative approach to hazard identification.

  20. Synthesis of ZnO nanopencils using wet chemical method and its investigation as LPG sensor

    International Nuclear Information System (INIS)

    Shimpi, Navinchandra G.; Jain, Shilpa; Karmakar, Narayan; Shah, Akshara; Kothari, D.C.; Mishra, Satyendra

    2016-01-01

    Highlights: • Synthesis using a simple and cost-effective wet chemical process. • Uniform, monodispersed and pure nanoparticles. • Pencil shaped rods with sharp tips. • Understanding of Growth mechanism. • Efficient LPG sensing with high response. • Morphology dependent sensing. - Abstract: ZnO nanopencils (NPCs) were prepared by a novel wet chemical process, using triethanolamine (TEA) as a mild base, which is relatively simple and cost effective method as compared to hydrothermal method. ZnO NPCs were characterized using powder X-ray diffraction (XRD), Fourier Transform Infra-Red (FTIR) spectroscopy in mid-IR and far-IR regions, X-ray Photoelectron Spectroscopy (XPS), UV–vis (UV–vis) absorption spectroscopy, room temperature Photoluminescence (PL) spectroscopy and Field Emission Scanning Electron Microscopy (FESEM). ZnO NPCs obtained, were highly pure, uniform and monodispersed.XRD pattern indicated hexagonal unit cell structure with preferred orientation along the c-axis. Sensing behaviour of ZnO NPCs was studied towards Liquefied Petroleum Gas (LPG) at different operating temperatures. The study shows that ZnO NPCs were most sensitive and promising candidate for detection of LPG at 250 °C with gas sensitivity > 60%. The high response towards LPG is due to high surface area of ZnO NPCs and their parallel alignment.

  1. Immobilization methods for the rapid total chemical synthesis of proteins on microtiter plates.

    Science.gov (United States)

    Zitterbart, Robert; Krumrey, Michael; Seitz, Oliver

    2017-07-01

    The chemical synthesis of proteins typically involves the solid-phase peptide synthesis of unprotected peptide fragments that are stitched together in solution by native chemical ligation (NCL). The process is slow, and throughput is limited because of the need for repeated high performance liquid chromatography purification steps after both solid-phase peptide synthesis and NCL. With an aim to provide faster access to functional proteins and to accelerate the functional analysis of synthetic proteins by parallelization, we developed a method for the high performance liquid chromatography-free synthesis of proteins on the surface of microtiter plates. The method relies on solid-phase synthesis of unprotected peptide fragments, immobilization of the C-terminal fragment and on-surface NCL with an unprotected peptide thioester in crude form. Herein, we describe the development of a suitable immobilization chemistry. We compared (i) formation of nickel(II)-oligohistidine complexes, (ii) Cu-based [2 + 3] alkine-azide cycloaddition and (iii) hydrazone ligation. The comparative study identified the hydrazone ligation as most suitable. The sequence of immobilization via hydrazone ligation, on-surface NCL and radical desulfurization furnished the targeted SH3 domains in near quantitative yield. The synthetic proteins were functional as demonstrated by an on-surface fluorescence-based saturation binding analysis. Copyright © 2017 European Peptide Society and John Wiley & Sons, Ltd. Copyright © 2017 European Peptide Society and John Wiley & Sons, Ltd.

  2. Synthesis of ZnO nanopencils using wet chemical method and its investigation as LPG sensor

    Energy Technology Data Exchange (ETDEWEB)

    Shimpi, Navinchandra G., E-mail: navin_shimpi@rediffmail.com [Department of Chemistry, University of Mumbai, Santacruz (East), Mumbai-400098 (India); Jain, Shilpa [Department of Chemistry, University of Mumbai, Santacruz (East), Mumbai-400098 (India); Karmakar, Narayan [Department of Physics, University of Mumbai, Santacruz (East), Mumbai-400098 (India); Shah, Akshara [Department of Chemistry, University of Mumbai, Santacruz (East), Mumbai-400098 (India); Kothari, D.C. [Department of Physics, University of Mumbai, Santacruz (East), Mumbai-400098 (India); National Centre for Nanosciences & Nanotechnology, University of Mumbai, Santacruz (East), Mumbai-400098 (India); Mishra, Satyendra [University Institute of Chemical Technology, North Maharashtra University, Jalgaon (India)

    2016-12-30

    Highlights: • Synthesis using a simple and cost-effective wet chemical process. • Uniform, monodispersed and pure nanoparticles. • Pencil shaped rods with sharp tips. • Understanding of Growth mechanism. • Efficient LPG sensing with high response. • Morphology dependent sensing. - Abstract: ZnO nanopencils (NPCs) were prepared by a novel wet chemical process, using triethanolamine (TEA) as a mild base, which is relatively simple and cost effective method as compared to hydrothermal method. ZnO NPCs were characterized using powder X-ray diffraction (XRD), Fourier Transform Infra-Red (FTIR) spectroscopy in mid-IR and far-IR regions, X-ray Photoelectron Spectroscopy (XPS), UV–vis (UV–vis) absorption spectroscopy, room temperature Photoluminescence (PL) spectroscopy and Field Emission Scanning Electron Microscopy (FESEM). ZnO NPCs obtained, were highly pure, uniform and monodispersed.XRD pattern indicated hexagonal unit cell structure with preferred orientation along the c-axis. Sensing behaviour of ZnO NPCs was studied towards Liquefied Petroleum Gas (LPG) at different operating temperatures. The study shows that ZnO NPCs were most sensitive and promising candidate for detection of LPG at 250 °C with gas sensitivity > 60%. The high response towards LPG is due to high surface area of ZnO NPCs and their parallel alignment.

  3. Atomic force microscopy of histological sections using a chemical etching method

    International Nuclear Information System (INIS)

    Tiribilli, B.; Bani, D.; Quercioli, F.; Ghirelli, A.; Vassalli, M.

    2005-01-01

    Physiology and pathology have a big deal on tissue morphology, and the intrinsic spatial resolution of an atomic force microscope (AFM) is able to observe ultrastructural details. In order to investigate cellular and subcellular structures in histological sections with the AFM, we used a new simple method for sample preparation, i.e. chemical etching of semithin sections from epoxy resin-embedded specimens: such treatment appears to melt the upper layers of the embedding resin; thus, removing the superficial roughness caused by the edge of the microtome knife and bringing into high relief the biological structures hidden in the bulk. Consecutive ultrathin sections embedded in epoxy resin were observed with a transmission electron microscope (TEM) to compare the different imaging properties on the same specimen sample. In this paper we report, as an example, our AFM and TEM images of two different tissue specimens, rat pancreas and skeletal muscle fibres, showing that most of the inner details are visible with the AFM. These results suggest that chemical etching of histological sections may be a simple, fast and cost-effective method for AFM imaging with ultrastructural resolution

  4. Big (Bio)Chemical Data Mining Using Chemometric Methods: A Need for Chemists.

    Science.gov (United States)

    Tauler, Roma; Parastar, Hadi

    2018-03-23

    This review aims to demonstrate abilities to analyze Big (Bio)Chemical Data (BBCD) with multivariate chemometric methods and to show some of the more important challenges of modern analytical researches. In this review, the capabilities and versatility of chemometric methods will be discussed in light of the BBCD challenges that are being encountered in chromatographic, spectroscopic and hyperspectral imaging measurements, with an emphasis on their application to omics sciences. In addition, insights and perspectives on how to address the analysis of BBCD are provided along with a discussion of the procedures necessary to obtain more reliable qualitative and quantitative results. In this review, the importance of Big Data and of their relevance to (bio)chemistry are first discussed. Then, analytical tools which can produce BBCD are presented as well as some basics needed to understand prospects and limitations of chemometric techniques when they are applied to BBCD are given. Finally, the significance of the combination of chemometric approaches with BBCD analysis in different chemical disciplines is highlighted with some examples. In this paper, we have tried to cover some of the applications of big data analysis in the (bio)chemistry field. However, this coverage is not extensive covering everything done in the field. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Alternative Chemical Cleaning Methods for High Level Waste Tanks: Simulant Studies

    Energy Technology Data Exchange (ETDEWEB)

    Rudisill, T. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); King, W. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Hay, M. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Jones, D. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2015-11-19

    Solubility testing with simulated High Level Waste tank heel solids has been conducted in order to evaluate two alternative chemical cleaning technologies for the dissolution of sludge residuals remaining in the tanks after the exhaustion of mechanical cleaning and sludge washing efforts. Tests were conducted with non-radioactive pure phase metal reagents, binary mixtures of reagents, and a Savannah River Site PUREX heel simulant to determine the effectiveness of an optimized, dilute oxalic/nitric acid cleaning reagent and pure, dilute nitric acid toward dissolving the bulk non-radioactive waste components. A focus of this testing was on minimization of oxalic acid additions during tank cleaning. For comparison purposes, separate samples were also contacted with pure, concentrated oxalic acid which is the current baseline chemical cleaning reagent. In a separate study, solubility tests were conducted with radioactive tank heel simulants using acidic and caustic permanganate-based methods focused on the “targeted” dissolution of actinide species known to be drivers for Savannah River Site tank closure Performance Assessments. Permanganate-based cleaning methods were evaluated prior to and after oxalic acid contact.

  6. Controlled growth of epitaxial CeO2 thin films with self-organized nanostructure by chemical solution method

    DEFF Research Database (Denmark)

    Yue, Zhao; Grivel, Jean-Claude

    2013-01-01

    Chemical solution deposition is a versatile technique to grow oxide thin films with self-organized nanostructures. Morphology and crystallographic orientation control of CeO2 thin films grown on technical NiW substrates by a chemical solution deposition method are achieved in this work. Based...

  7. Methods of direct (non-chromatographic) quantification of body metabolites utilizing chemical ionization mass spectrometry

    International Nuclear Information System (INIS)

    Mee, J.M.L.

    1978-01-01

    For quantitative determination of known metabolites from the biological sample by direct chemical ionization mass spectrometry (CI-MS), the method of internal standard using stable isotopically labelled analogs appears to be the method of choice. In the case where stable isotope ratio determinations could not be applied, and alternative quantification can be achieved using non-labelled external or internal standards and a calibration curve (sum of peak height per a given number of scans versus concentration). The technique of computer monitoring permits display and plotting of ion current profiles (TIC and SIC) or spectra per a given number of scans or a given range of mass per charge. Examples are given in areas of clinical application and the quantitative data show very good agreement with the conventional chromatographic measurements. (Auth.)

  8. Surface plasmon resonance based sensing of different chemical and biological samples using admittance loci method

    Science.gov (United States)

    Brahmachari, Kaushik; Ghosh, Sharmila; Ray, Mina

    2013-06-01

    The admittance loci method plays an important role in the design of multilayer thin film structures. In this paper, admittance loci method has been explored theoretically for sensing of various chemical and biological samples based on surface plasmon resonance (SPR) phenomenon. A dielectric multilayer structure consisting of a Boro silicate glass (BSG) substrate, calcium fluoride (CaF2) and zirconium dioxide (ZrO2) along with different dielectric layers has been investigated. Moreover, admittance loci as well as SPR curves of metal-dielectric multilayer structure consisting of the BSG substrate, gold metal film and various dielectric samples has been simulated in MATLAB environment. To validate the proposed simulation results, calibration curves have also been provided.

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

    International Nuclear Information System (INIS)

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

    2008-01-01

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

  10. Standard test methods for chemical, mass spectrometric, and spectrochemical analysis of nuclear-grade boron carbide

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2004-01-01

    1.1 These test methods cover procedures for the chemical, mass spectrometric, and spectrochemical analysis of nuclear-grade boron carbide powder and pellets to determine compliance with specifications. 1.2 The analytical procedures appear in the following order: Sections Total Carbon by Combustion and Gravimetry 7-17 Total Boron by Titrimetry 18-28 Isotopic Composition by Mass Spectrometry 29-38 Chloride and Fluoride Separation by Pyrohydrolysis 39-45 Chloride by Constant-Current Coulometry 46-54 Fluoride by Ion-Selective Electrode 55-63 Water by Constant-Voltage Coulometry 64-72 Impurities by Spectrochemical Analysis 73-81 Soluble Boron by Titrimetry 82-95 Soluble Carbon by a Manometric Measurement 96-105 Metallic Impurities by a Direct Reader Spectrometric Method 106-114

  11. Chemical intermediate detection following corona discharge on volatile organic compounds: general method using molecular beam techniques

    International Nuclear Information System (INIS)

    He Luning; Sulkes, Mark

    2011-01-01

    Nonthermal plasma (NTP)-based treatments of volatile organic compounds (VOCs) have potential for effective environmental remediation. Theory and experiment that consider the basic science pertaining to discharge events have helped improve NTP remediation outcomes. If direct information on early post-discharge chemical intermediates were also available, it would likely lead to additional improvement in NTP remediation outcomes. To this point, however, experiments yielding direct information on post-NTP VOC intermediates have been limited. An approach using supersonic expansion molecular beam methods offers general promise for detection of post-discharge VOC intermediates. To illustrate the potential utility of these methods, we present mass spectra showing the growth of early products formed when pulsed corona discharges were carried out on toluene in He and then in He with added O 2 . Good general detection of neutral post-discharge species was obtained using 800 nm 150 fs photoionization pulses.

  12. Comparison of Selected Methods for Individual Decontamination of Chemical Warfare Agents

    Directory of Open Access Journals (Sweden)

    Tomas Capoun

    2014-06-01

    Full Text Available This study addresses the individual decontamination of chemical warfare agents (CWA and other hazardous substances. The individual decontamination applies to contaminated body surfaces, protective clothing and objects immediately after contamination, performed individually or by mutual assistance using prescribed or improvised devices. The article evaluates the importance of individual decontamination, security level for Fire and Rescue Service Units of the Czech Republic (FRS CR and demonstrates some of the devices. The decontamination efficiency of selected methods (sorbent, glove and sponge, two-chamber foam device and wiping with alcohol was evaluated for protective clothing and painted steel plate contaminated with O-ethyl-S-(diisopropylaminoethyl-methylthiophosphonate (VX, sulfur mustard, o-cresol and acrylonitrile. The methods were assessed from an economic point of view and with regard to specific user parameters, such as the decontamination of surfaces or materials with poor accessibility and vertical surfaces, the need for a water rinse as well as toxic waste and its disposal.

  13. The New version of Danish food composition database FRIDA including a case study on recipe calculation compared to a chemical analysis

    DEFF Research Database (Denmark)

    weighed. Typical components were bread, French fries, vegetables, meat, and dressings. The fast foods were analyzed and the content of energy, protein, saturated fat, iron, thiamin, potassium and sodium were compared to recipe calculation. Wilcoxon Signed Rank test, Spearman correlation coefficients......%). Correlations ranged from 0.49 for iron to 0.75 for energy. Bland-Altman plots showed larger differences for higher contents for thiamin and potassium. Results depended on the type of fast food. For burgers (n=36) there was no significant difference for any of the nutrients between the two methods. Meat/French......Objective: Constantly updated food data that reflect the food supply, such as the recently published http://frida.fooddata.dk, is essential for recipe calculation in dietary assessment. The objective of this study was to compare the content of selected nutrients estimated by recipe calculation...

  14. Some observations concerning blade-element-momentum (BEM) methods and vortex wake methods, including numerical experiments with a simple vortex model

    Energy Technology Data Exchange (ETDEWEB)

    Snel, H. [Netherlands Energy Research Foundation ECN, Renewable Energy, Wind Energy (Netherlands)

    1997-08-01

    Recently the Blade Element Momentum (BEM) method has been made more versatile. Inclusion of rotational effects on time averaged profile coefficients have improved its achievements for performance calculations in stalled flow. Time dependence as a result of turbulent inflow, pitching actions and yawed operation is now treated more correctly (although more improvement is needed) than before. It is of interest to note that adaptations in modelling of unsteady or periodic induction stem from qualitative and quantitative insights obtained from free vortex models. Free vortex methods and further into the future Navier Stokes (NS) calculations, together with wind tunnel and field experiments, can be very useful in enhancing the potential of BEM for aero-elastic response calculations. It must be kept in mind however that extreme caution must be used with free vortex methods, as will be discussed in the following chapters. A discussion of the shortcomings and the strength of BEM and of vortex wake models is given. Some ideas are presented on how BEM might be improved without too much loss of efficiency. (EG)

  15. A comparison of partial order technique with three methods of multi-criteria analysis for ranking of chemical substances.

    Science.gov (United States)

    Lerche, Dorte; Brüggemann, Rainer; Sørensen, Peter; Carlsen, Lars; Nielsen, Ole John

    2002-01-01

    An alternative to the often cumbersome and time-consuming risk assessments of chemical substances could be more reliable and advanced priority setting methods. An elaboration of the simple scoring methods is provided by Hasse Diagram Technique (HDT) and/or Multi-Criteria Analysis (MCA). The present study provides an in depth evaluation of HDT relative to three MCA techniques. The new and main methodological step in the comparison is the use of probability concepts based on mathematical tools such as linear extensions of partially ordered sets and Monte Carlo simulations. A data set consisting of 12 High Production Volume Chemicals (HPVCs) is used for illustration. It is a paradigm in this investigation to claim that the need of external input (often subjective weightings of criteria) should be minimized and that the transparency should be maximized in any multicriteria prioritisation. The study illustrates that the Hasse diagram technique (HDT) needs least external input, is most transparent and is least subjective. However, HDT has some weaknesses if there are criteria which exclude each other. Then weighting is needed. Multi-Criteria Analysis (i.e. Utility Function approach, PROMETHEE and concordance analysis) can deal with such mutual exclusions because their formalisms to quantify preferences allow participation e.g. weighting of criteria. Consequently MCA include more subjectivity and loose transparency. The recommendation which arises from this study is that the first step in decision making is to run HDT and as the second step possibly is to run one of the MCA algorithms.

  16. [Detection of nitrite and nitrosocompounds in chemical systems and biological liquids by the calorimetric method].

    Science.gov (United States)

    Titov, V Iu; Petrenko, Iu M; Vanin, A F; Stepuro, I I

    2010-01-01

    The capacity of nitrite, S-nitrosothiols (RS-NO), dinitrosyl iron complexes (DNICs) with thiol-containing ligands, and nitrosoamines to inhibit catalase has been used for the selective determination of these compounds in purely chemical systems and biological liquids: cow milk and colostram. The limiting sensitivity of the method is 50 nM. A comparison of the results of the determinations of RS-NO, DNIC, and nitrite by the catalase method and the Greese method conventionally used for nitrite detection showed that, firstly, Greese reagents decompose DNIC and RS-NO to form nitrite. Therefore, the Greese method cannot be used for nitrite determination in solutions of these substances. Secondly, Greese reagents interact with complexes of mercury ions with RS-NO, inducing the release of nitrosonium ions from the complex followed by the hydrolysis of nitrosonium to nitrite. Thus, the proposition about the spontaneous decay of the complexes of mercury ions with RS-NO is incorrect. Keeping in mind a high sensitivity of the method, the use of catalase as an enzyme detector of nitrosocompounds allows one to detect these compounds in neutral medium without prior purification of the object, thereby preventing artificial effects due to noncontrolled modifications of the compounds under study.

  17. Quantitative phase analysis using the whole-powder-pattern decomposition method. Pt. 1. Solution from knowledge of chemical compositions

    International Nuclear Information System (INIS)

    Toraya, H.; Tusaka, S.

    1995-01-01

    A new procedure for quantitative phase analysis using the whole-powder-pattern decomposition method is proposed. The procedure consists of two steps. In the first, the whole powder patterns of single-component materials are decomposed separately. The refined parameters of integrated intensity, unit cell and profile shape for respective phases are stored in computer data files. In the second step, the whole powder pattern of a mixture sample is fitted, where the parameters refined in the previous step are used to calculate the profile intensity. The integrated intensity parameters are, however, not varied during the least-squares fitting, while the scale factors for the profile intensities of individual phases are adjusted instead. Weight fractions are obtained by solving simultaneous equations, coefficients of which include the scale factors and the mass-absorption coefficients calculated from chemical formulas of respective phases. The procedure can be applied to all mixture samples, including those containing an amorphous material, if single-component samples with known chemical compositions and their approximate unit-cell parameters are provided. The procedure has been tested by using two-to five-component samples, giving average deviations of 1 to 1.5%. Optimum refinement conditions are discussed in connection with the accuracy of the procedure. (orig.)

  18. Odor and odorous chemical emissions from animal buildings: part 1 - project overview, collection methods, and quality control

    Science.gov (United States)

    Livestock facilities have historically generated public concerns due to their emissions of odorous air and various chemical pollutants. Odor emission factors and identification of principal odorous chemicals are needed to better understand the problem. Applications of odor emission factors include i...

  19. Characterization of Korean Red Ginseng (Panax ginseng Meyer: History, preparation method, and chemical composition

    Directory of Open Access Journals (Sweden)

    Sang Myung Lee

    2015-10-01

    Full Text Available It has been reported that Korean Red Ginseng has been manufactured for 1,123 y as described in the GoRyeoDoGyeong record. The Korean Red Ginseng manufactured by the traditional preparation method has its own chemical component characteristics. The ginsenoside content of the red ginseng is shown as Rg1: 3.3 mg/g, Re: 2.0 mg/g, Rb1: 5.8 mg/g, Rc:1.7 mg/g, Rb2: 2.3 mg/g, and Rd: 0.4 mg/g, respectively. It is known that Korean ginseng generally consists of the main root and the lateral or fine roots at a ratio of about 75:25. Therefore, the red ginseng extract is prepared by using this same ratio of the main root and lateral or fine roots and processed by the historical traditional medicine prescription. The red ginseng extract is prepared through a water extraction (90°C for 14–16 h and concentration process (until its final concentration is 70–73 Brix at 50–60°C. The ginsenoside contents of the red ginseng extract are shown as Rg1: 1.3 mg/g, Re: 1.3 mg/g, Rb1: 6.4 mg/g, Rc:2.5 mg/g, Rb2: 2.3 mg/g, and Rd: 0.9 mg/g, respectively. Arginine-fructose-glucose (AFG is a specific amino-sugar that can be produced by chemical reaction of the process when the fresh ginseng is converted to red ginseng. The content of AFG is 1.0–1.5% in red ginseng. Acidic polysaccharide, which has been known as an immune activator, is at levels of 4.5–7.5% in red ginseng. Therefore, we recommended that the chemical profiles of Korean Red Ginseng made through the defined traditional method should be well preserved and it has had its own chemical characteristics since its traditional development.

  20. Robust chemical and chemical-resistant material detection using hyper-spectral imager and a new bend interpolation and local scaling HSI sharpening method

    Science.gov (United States)

    Chen, Hai-Wen; McGurr, Michael; Brickhouse, Mark

    2015-05-01

    We present new results from our ongoing research activity for chemical threat detection using hyper-spectral imager (HSI) detection techniques by detecting nontraditional threat spectral signatures of agent usage, such as protective equipment, coatings, paints, spills, and stains that are worn by human or on trucks or other objects. We have applied several current state-of-the-art HSI target detection methods such as Matched Filter (MF), Adaptive Coherence Estimator (ACE), Constrained Energy Minimization (CEM), and Spectral Angle Mapper (SAM). We are interested in detecting several chemical related materials: (a) Tyvek clothing is chemical resistance and Tyvek coveralls are one-piece garments for protecting human body from harmful chemicals, and (b) ammonium salts from background could be representative of spills from scrubbers or related to other chemical activities. The HSI dataset that we used for detection covers a chemical test field with more than 50 different kinds of chemicals, protective materials, coatings, and paints. Among them, there are four different kinds of Tyvek material, three types of ammonium salts, and one yellow jugs. The imagery cube data were collected by a HSI sensor with a spectral range of 400-2,500nm. Preliminary testing results are promising, and very high probability of detection (Pd) and low probability of false detection are achieved with the usage of full spectral range (400- 2,500nm). In the second part of this paper, we present our newly developed HSI sharpening technique. A new Band Interpolation and Local Scaling (BILS) method has been developed to improve HSI spatial resolution by 4-16 times with a low-cost high-resolution pen-chromatic camera and a RGB camera. Preliminary results indicate that this new technique is promising.

  1. Electrochromic and electrochemical capacitive properties of tungsten oxide and its polyaniline nanocomposite films obtained by chemical bath deposition method

    CSIR Research Space (South Africa)

    Nwanya, AC

    2014-05-01

    Full Text Available Polyanine and its nanocomposite WO3/PANI films were deposited on fluorine doped tin oxide (FTO) glassslides by simple chemical bath deposition method. The morphology structure of the composite film wasstudied using atomic force microscopy (AFM...

  2. Evaluating the impacts of membrane type, coating, fouling, chemical properties and water chemistry on reverse osmosis rejection of seven nitrosoalklyamines, including NDMA.

    Science.gov (United States)

    Steinle-Darling, Eva; Zedda, Marco; Plumlee, Megan H; Ridgway, Harry F; Reinhard, Martin

    2007-09-01

    Reverse osmosis (RO) treatment has been found to be effective for a wide range of organics but generally small, polar, uncharged molecules such as N-nitrosodimethylamine (NDMA) can be poorly rejected. The rejection of seven N-nitrosoalkylamines with molecular masses in the range of 78-158Da, including NDMA, N-nitrosodiethylamine (NDEA), N-nitrosomethylethylamine (NMEA), N-nitrosodipropylamine (NDPA), N-nitrosodibutylamine (NDBA), N-nitrosopyrrolidine (NPyr), N-nitrosopiperidine (NPip) by three commercial brackish-water reverse osmosis membranes was studied in flat-sheet cells under cross-flow conditions. The membranes used were ESPA3 (Hydranautics), LFC3 (Hydranautics) and BW-30 (Dow/Filmtec), commonly used in water reuse applications. The effects of varying ionic strength and pH, dip-coating membranes with PEBAX 1657, a hydrophilic polymer, and artificial fouling with alginate on nitrosamine rejection were quantified. Rejection in deionized (DI) water increased with molecular mass from 56 to 70% for NDMA, to 80-91% for NMEA, 89-97% for NPyr, 92-98% for NDEA, and to beyond the detection limits for NPip, NDPA and NDBA. For the nitrosamines with quantifiable transmission, linear correlations (r(2)>0.97) were found between the number of methyl groups and the log(transmission), with factor 0.35 to 0.55 decreases in transmission per added methyl group. A PEBAX coating lowered the ESPA3 rejection of NDMA by 11% but increased the LFC3 and BW30 rejection by 6% and 15%, respectively. Artificially fouling ESPA3 membrane coupons with 170g/m(2) alginate decreased the rejection of NDMA by 18%. A feed concentration of 100mM NaCl decreased rejection of NDMA by 15% and acidifying the DI water feed to pH=3 decreased the rejection by 5%, whereas increasing the pH to 10 did not have a significant (p<0.05) effect.

  3. Study of the efficiency of chemically assisted enucleation method for handmade cloning in goat (Capra hircus).

    Science.gov (United States)

    Akshey, Y S; Malakar, D; De, A K; Jena, M K; Sahu, S; Dutta, R

    2011-08-01

    The present investigation was carried out to find an efficient chemically assisted procedure for enucleation of goat oocytes related to handmade cloning (HMC) technique. After 22-h in vitro maturation, oocytes were incubated with 0.5 μg/ml demecolcine for 2 h. Cumulus cells were removed by pipetting and vortexing in 0.5 mg/ml hyaluronidase, and zona pellucida were digested with pronase. Oocytes with extrusion cones were subjected to oriented bisection. One-third of the cytoplasm with the extrusion cone was removed with a micro blade. The remaining cytoplasts were used as recipients in HMC. Goat foetal fibroblasts were used as nuclear donors. The overall efficiency measured as the number of cytoplasts obtained per total number of oocytes used was significantly (p < 0.05) higher in chemically assisted handmade enucleation (CAHE) than oriented handmade enucleation without demecolcine (OHE) (80.02 ± 1.292% vs. 72.9 ± 1.00%, respectively, mean ± SEM). The reconstructed and activated embryos were cultured in embryo development medium (EDM) for 7 days. Fusion, cleavage and blastocyst development rate were 71.63 ± 1.95%, 92.94 ± 0.91% and 23.78 ± 3.33% (mean ± SEM), respectively which did not differ significantly from those achieved with random handmade enucleation and OHE. In conclusion, chemically assisted enucleation is a highly efficient and reliable enucleation method for goat HMC which eliminates the need of expensive equipment (inverted fluorescence microscope) and potentially harmful chromatin staining and ultraviolet (UV) irradiation for cytoplast selection. © 2010 Blackwell Verlag GmbH.

  4. Standard methods for chemical, mass spectrometric, spectrochemical, nuclear, and radiochemical analysis of uranium hexafluoride

    International Nuclear Information System (INIS)

    Anon.

    1975-01-01

    All methods described for subsampling and analysis of UF 6 are in routine use at United States Atomic Energy Commission installations. A gravimetric method is included for U and titrimetric methods, for Cl 2 and U. Mass spectrometric methods are given for both double and single standard procedures for U-isotopic content and for semiquantitative determination of hydrocarbons, chlorocarbons, and partially substituted halohydrocarbons. Spectroscopic methods are described for 232 U, fission products, Pu, and Np. In some instances an ion exchange- or extraction-separation is specified prior to the spectroscopic determination. Mass spectroscopic procedures for 31 trace elements are included, as are spectrophotometric methods for Br 2 , Si, P, Ti, V, W, Th, and Mo. Following a preliminary separation for some elements, emission spectroscopic procedures are described for B, Si, Ru, Hf, Mo, Nb, Ta, Ti, W, Zr, V, Th, rare earths, and other elements. Procedures for the determination of Sb, Ru, Al, Cd, Co, Ca, Cr, Fe, Pb, Mg, Mn, Ni, K, Na, and Zn by atomic absorption methods are included. The preparation of high-purity U 3 O 8 by the hydrolysis of UF 6 to UO 2 F 2 which upon drying and pyrohydrolysis yields U 3 O 8 is described

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

    Science.gov (United States)

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

    2017-12-01

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

  6. Study on CexLa1-xO2 Buffer Layer used in Coated Conductors by Chemical Solution Method

    DEFF Research Database (Denmark)

    Zhao, Yue; Suo, Hongli; Grivel, Jean-Claude

    2009-01-01

    Developing multi-functional single buffer layer is one of the most important challenges for simplification of coated conductors configuration. Ladoped CeO2 films were prepared by chemical solution method. And surface morphology and texture quality of the La-doped CeO2 films were investigated...... method. It suggects that Ce0.9La0.1O2 film prepared by chemical solution route have a promising prospect for the simplification of coated conductors configuration....

  7. Study on the chemical stability of catalyst counter electrodes for dye-sensitized solar cells using a simple X-ray photoelectron spectroscopy-based method

    Science.gov (United States)

    Yun, Dong-Jin; Kim, Jungmin; Chung, Jongwon; Park, SungHoon; Baek, WoonJoong; Kim, Yongsu; Kim, Seongheon; Kwon, Young-Nam; Chung, JaeGwan; Kyoung, Yongkoo; Kim, Ki-Hong; Heo, Sung

    2014-12-01

    Since the chemical/electrical stability and catalytic activity are essential conditions for catalyst counter electrodes (CCEs) in dye-sensitized solar cells (DSSCs), a simple dipping method is employed for evaluating the chemical stability of CCE candidates in an iodine-based liquid electrolyte (I-electrolyte). The chemical stabilities and transition mechanisms of the CCEs are successfully analyzed by studying the chemical transitions in X-ray photoelectron spectroscopy (XPS) core levels after dipping in the I-electrolyte. All films including the Pt film undergo degradation depending on the type of material. While dipping in the I-electrolyte, Cu and Au films scarcely dissolves as their respective metal sulfides, and the Al film gradually loss its metallic properties owing to Al2O3 growth. On the other hand, a previously unknown transition mechanism of organic conducting CCEs is determined based on the proposed method. Compared to the other metal films, the poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate) (PEDOT:PSS) and multi wall carbon nanotube (MWCNT)/PEDOT:PSS films undergo an entirely unique transition mechanism, which results from the chemical adsorption of organic molecules onto PEDOT:PSS molecules in the I-electrolyte. Consequently, these chemical structure transitions correspond well to the degrees of alternation in the electrical properties of DSSCs with all the investigated CCEs.

  8. The synthesis and characterization of W- 1wt. % TiC alloy using a chemical method

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Tae Hee; Ryu, Ho Jin [KAIST, Daejeon (Korea, Republic of)

    2016-05-15

    Many studies have demonstrated the dispersed second phase nanoparticles in the tungsten matrix inhibit the grain growth and recrystallization, besides they improve the ductility and the irradiation resistance by hindering grain boundary sliding and stabilizing the microstructure.7 La{sub 2}O{sub 3}, Y{sub 2}O{sub 3}, TiC or ZrC particles are usually added to tungsten. However, some crucial issues should be solved such as the uniform distribution of these second phase particles and the industrial mass production. By using typical mechanical alloying and powder metallurgy, nanoparticles tend to be agglomerated and concentrated at the grain boundaries due to the high surface energies introduced. Moreover, the milling process often produces detrimental phase by the wear of the milling equipment and media. Xia et al. have firstly reported core-shell structured W/TiC using ammonium metatungstate ((NH{sub 4}){sub 6}W{sub 7}O{sub 24}·XH{sub 2}O, AMT) and hydrochloric acid. Nano-sized TiC particles are coated uniformly by AMT precipitation formed by the addition of hydrochloric acid to the AMT solution. The core-shell structure particles were examined by TEM. To achieve uniform distribution of TiC nanoparticles, a wet chemical method is essential rather than typical mechanical alloying. Also, the use of the chemical method of alloying can be easily applied to the industry with cost-effective and environmental benefits. The purpose of this study is to achieve uniform distribution of TiC nano-particles within the tungsten matrix, as the literature has studied. Moreover, the chemical methods could be applied to other refectory metals such as molybdenum. The obtained powder was reduced and sintered using SPS technique. The relative density of sintered sample achieved was 97%. Furthermore, the microstructure of the sintered sample was analyzed using FE-SEM and the presence of TiC particles at the grain boundary and grain interior was confirmed by EDS.

  9. Artificial intelligence/fuzzy logic method for analysis of combined signals from heavy metal chemical sensors

    International Nuclear Information System (INIS)

    Turek, M.; Heiden, W.; Riesen, A.; Chhabda, T.A.; Schubert, J.; Zander, W.; Krueger, P.; Keusgen, M.; Schoening, M.J.

    2009-01-01

    The cross-sensitivity of chemical sensors for several metal ions resembles in a way the overlapping sensitivity of some biological sensors, like the optical colour receptors of human retinal cone cells. While it is difficult to assign crisp classification values to measurands based on complex overlapping sensory signals, fuzzy logic offers a possibility to mathematically model such systems. Current work goes into the direction of mixed heavy metal solutions and the combination of fuzzy logic with heavy metal-sensitive, silicon-based chemical sensors for training scenarios of arbitrary sensor/probe combinations in terms of an electronic tongue. Heavy metals play an important role in environmental analysis. As trace elements as well as water impurities released from industrial processes they occur in the environment. In this work, the development of a new fuzzy logic method based on potentiometric measurements performed with three different miniaturised chalcogenide glass sensors in different heavy metal solutions will be presented. The critical validation of the developed fuzzy logic program will be demonstrated by means of measurements in unknown single- and multi-component heavy metal solutions. Limitations of this program and a comparison between calculated and expected values in terms of analyte composition and heavy metal ion concentration will be shown and discussed.

  10. Fabrication of ZnO nanorod using spray-pyrolysis and chemical bath deposition method

    Energy Technology Data Exchange (ETDEWEB)

    Ramadhani, Muhammad F., E-mail: brian@tf.itb.ac.id; Pasaribu, Maruli A. H., E-mail: brian@tf.itb.ac.id; Yuliarto, Brian, E-mail: brian@tf.itb.ac.id; Nugraha, E-mail: brian@tf.itb.ac.id [Advanced Functional Materials Laboratory, Engineering Physics Department Faculty of Industrial Technology, Institut Teknologi Bandung (Indonesia)

    2014-02-24

    ZnO thin films with nanorod structure were deposited using Ultrasonic Spray Pyrolysis method for seed growth, and Chemical Bath Deposition (CBD) for nanorod growth. High purity Zn-hydrate and Urea are used to control Ph were dissolved in ethanol and aqua bidest in Ultrasonic Spray Pyrolysis process. Glass substrate was placed above the heater plate of reaction chamber, and subsequently sprayed with the range duration of 5, 10 and 20 minutes at the temperatures of 3500 C. As for the Chemical Bath Deposition, the glass substrate with ZnO seed on the surface was immerse to Zn-hydrate, HMTA (Hexa Methylene Tetra Amine) and deionized water solution for duration of 3, 5 and 7 hour and temperatures of 600 C, washed in distilled water, dried, and annealed at 3500 C for an hour. The characterization of samples was carried out to reveal the surface morphology using Scanning Electron Microscopy (SEM). From the data, the combination of 5 minutes of Ultrasonic Spray Pyrolysis process and 3 hour of CBD has showed the best structure of nanorod. Meanwhile the longer Spraying process and CBD yield the bigger nanorod structure that have been made, and it makes the films more dense which make the nanorod collide each other and as a result produce unsymetric nanorod structure.

  11. Investigation of microstructure and mechanical properties of phosphocalcic bone substitute using the chemical wet method

    Science.gov (United States)

    Alimi, Latifa; Bahloul, Lynda; Azzi, Afef; Guerfi, Souad; Ismail, Fadhel; Chaoui, Kamel

    2018-05-01

    Selection of calcium phosphate base materials in reconstructive bone surgery is justified by the surprising similarities in chemical compositions with human bones. The closest to natural apatite material is the hydroxyapatite (HAp) which has a chemical composition based on calcium and phosphate (Ca10(PO4)6(OH)2). In this study, HAp is synthesized using the wet precipitation method from hydrated calcium chloride (CaCl2,12H2O) and di-sodium hydrogen phosphate di-hydrate (HNa2PO4,2H2O). The powder is calcinated at 900°C and 1200°C in order to compare with sintered condition at 1150°C. Vickers microhardness tests and X-ray diffraction analyzes are used for the characterization of the crystalline material. Mechanical properties (Hv, σe, σr, and KC) and the degree of crystallinity (Xc) are discussed according to heat treatment temperatures. Results indicate that heat treating the powder at 1200°C increased crystallinity up to 72%. At the same time, microhardness increased with temperature and even outmatched the sintered case at 1150°C. Fracture toughness is ameliorated with increasing heat treatment temperature by more than two folds.

  12. Artificial intelligence/fuzzy logic method for analysis of combined signals from heavy metal chemical sensors

    Energy Technology Data Exchange (ETDEWEB)

    Turek, M. [Institute of Nano- and Biotechnologies (INB), Aachen University of Applied Sciences, Campus Juelich, Juelich (Germany); Institute of Bio- and Nanosystems (IBN), Research Centre Juelich GmbH, Juelich (Germany); Heiden, W.; Riesen, A. [Bonn-Rhein-Sieg University of Applied Sciences, Sankt Augustin (Germany); Chhabda, T.A. [Institute of Nano- and Biotechnologies (INB), Aachen University of Applied Sciences, Campus Juelich, Juelich (Germany); Schubert, J.; Zander, W. [Institute of Bio- and Nanosystems (IBN), Research Centre Juelich GmbH, Juelich (Germany); Krueger, P. [Institute of Biochemistry and Molecular Biology, RWTH Aachen, Aachen (Germany); Keusgen, M. [Institute for Pharmaceutical Chemistry, Philipps-University Marburg, Marburg (Germany); Schoening, M.J. [Institute of Nano- and Biotechnologies (INB), Aachen University of Applied Sciences, Campus Juelich, Juelich (Germany); Institute of Bio- and Nanosystems (IBN), Research Centre Juelich GmbH, Juelich (Germany)], E-mail: m.j.schoening@fz-juelich.de

    2009-10-30

    The cross-sensitivity of chemical sensors for several metal ions resembles in a way the overlapping sensitivity of some biological sensors, like the optical colour receptors of human retinal cone cells. While it is difficult to assign crisp classification values to measurands based on complex overlapping sensory signals, fuzzy logic offers a possibility to mathematically model such systems. Current work goes into the direction of mixed heavy metal solutions and the combination of fuzzy logic with heavy metal-sensitive, silicon-based chemical sensors for training scenarios of arbitrary sensor/probe combinations in terms of an electronic tongue. Heavy metals play an important role in environmental analysis. As trace elements as well as water impurities released from industrial processes they occur in the environment. In this work, the development of a new fuzzy logic method based on potentiometric measurements performed with three different miniaturised chalcogenide glass sensors in different heavy metal solutions will be presented. The critical validation of the developed fuzzy logic program will be demonstrated by means of measurements in unknown single- and multi-component heavy metal solutions. Limitations of this program and a comparison between calculated and expected values in terms of analyte composition and heavy metal ion concentration will be shown and discussed.

  13. Application of chemical methods to assess the mechanism of alkali activation in low calcium fly ash

    Energy Technology Data Exchange (ETDEWEB)

    Arjunan, P.; Silsbee, M.R.; Roy, D.M. [Pennsylvania State Univ., PA (United States). Materials Research Lab.

    1999-11-01

    A better understanding of the amount of fly ash unreacted remaining after alkali activation of low calcium fly ash is necessary for elucidating the underlying alkali activation mechanism. An approach to this determination is reported in this study which utilizes an ethylenediamine tetraacetic acid/triethanolamine/NaOH mixture to determine the unreacted fly ash particles present in an OPC-low calcium fly ash mixture, with and without alkali activation. This study also uses another chemical technique called orthophosphoric acid dissolution method to assess the amount of unreacted crystalline phases present in hydrated OPC-ash mixtures at different ages of hydration. The information obtained from these two chemical techniques was used to identify the nature of unreacted fly ash particles present in the hydrated samples. The amount of unreacted fly ash and the compressive strength data were correlated to assess the extent of influence of alkali activation on the reactivity of the amorphous and crystalline phase content of the low calcium fly ash.

  14. Definite influence of the extraction methods on the chemical composition of virgin olive oil

    Directory of Open Access Journals (Sweden)

    Aparicio, R.

    1991-10-01

    Full Text Available The extraction methods of virgin olive oil affect the quantification values of some chemical compounds. Statistical tests and procedures have been applied to a set of 142 samples collected from all over Andalusia and characterized by 55 chemical compounds. It has been estimated that two aliphatic alcohols, one sterol and one fatty acid have the best significance levels identifying the extraction methodology (pressure, centrifugation. Stepwise Lineal Discriminant procedure has been used to characterize olive oils by the extraction systems. 205 samples from other provinces, varieties or harvests were used to verify these decision equations.

    Los métodos de extracción del aceite de oliva virgen afectan a los valores de algunos de sus componentes químicos. Se han aplicado métodos estadísticos a un conjunto de 142 muestras de Andalucía caracterizadas por 55 parámetros químicos. El mayor nivel de significación para la diferenciación de los sistemas de extracción se obtuvo con dos alcoholes alifáticos, un esterol y un ácido graso. Se ha utilizado el análisis discriminante por pasos para caracterizar los aceites según su sistema de extracción. 205 muestras de distinta procedencia, variedad y cosecha han sido utilizadas para conocer la bondad de los resultados.

  15. Chemical and ceramic methods for the safe storage of actinides using monazite. 1997 annual progress report

    International Nuclear Information System (INIS)

    Boatner, L.A.

    1997-01-01

    'Oak Ridge National Laboratory (ORNL) and the Rockwell Science Center of Thousand Oaks, California, are carrying out a joint investigation of the chemical, physical, thermal, and radiation-resistance properties of the lanthanide orthophosphates (monazites) in both ceramic and single-crystal form with the objective of developing the scientific and technical base required for the application of these materials to the storage or disposal of actinide elements, including plutonium. An additional major objective of the research effort is to investigate the technical and scientific problems associated with the formation of both phase-pure monazite ceramics and multiphase monazite-ceramic composites for waste disposal or waste storage applications. These latter investigations encompass the development of low-temperature chemical synthesis routes for the formation of monoclinic monazite phases and the study of the densification properties of lanthanide orthophosphate powders to produce stable, high-density ceramics. Research Statement This research effort addresses several basic issues associated with the characteristics of lanthanide orthophosphates that make this class of materials extremely attractive candidates for application to the storage of actinide elements in general and plutonium in particular. Additionally, these materials are potentially important refractory ceramics in their own right, and many of the scientific issues addressed in this project are applicable to the development of what will constitute a new, highly stable family of ceramics for applications in a number of energy-related areas.'

  16. Preparation of palladium nanoparticles on alumina surface by chemical co-precipitation method and catalytic applications

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Avvaru Praveen; Kumar, B. Prem; Kumar, A.B.V. Kiran; Huy, Bui The [Department of Chemistry, Changwon National University, Changwon 641-773 (Korea, Republic of); Lee, Yong-Ill, E-mail: yilee@changwon.ac.kr [Department of Chemistry, Changwon National University, Changwon 641-773 (Korea, Republic of)

    2013-01-15

    Highlights: Black-Right-Pointing-Pointer Facile synthesis of palladium nanoparticles on alumina surface. Black-Right-Pointing-Pointer The surface morphology and properties of the nanocrystalline powders were characterized. Black-Right-Pointing-Pointer The catalytic activities of palladium nanoparticles were investigated. - Abstract: The present work reports a chemical co-precipitation process to synthesize palladium (Pd) nanoparticles using alumina as a supporting material. The optimized temperature for the formation of nanocrystalline palladium was found to be 600 Degree-Sign C. The X-ray diffraction (XRD) and Raman spectroscopy were used to study the chemical nature of the Pd in alumina matrix. The surface morphology and properties of the nanocrystalline powders were examined using thermogravimetric analysis (TG-DTA), XRD, Raman spectroscopy, transmission electron microscopy (TEM), scanning electron microscopy (SEM) and atomic force microscopy (AFM). The calcinations in different atmospheres including in the inert medium forms the pure nano Pd{sup 0} while in the atmospheric air indicates the existence pure Pd{sup 0} along with PdO nanoparticles. The catalytic activities of the as-synthesized nanocrystalline Pd nanoparticles in the alumina matrix were investigated in Suzuki coupling, Hiyama cross-coupling, alkene and alkyne hydrogenation, and aerobic oxidation reactions.

  17. Novel fabrication of flexible graphene-based chemical sensors with heaters using soft lithographic patterning method.

    Science.gov (United States)

    Jung, Min Wook; Myung, Sung; Song, Wooseok; Kang, Min-A; Kim, Sung Ho; Yang, Cheol-Soo; Lee, Sun Sook; Lim, Jongsun; Park, Chong-Yun; Lee, Jeong-O; An, Ki-Seok

    2014-08-27

    We have fabricated graphene-based chemical sensors with flexible heaters for the highly sensitive detection of specific gases. We believe that increasing the temperature of the graphene surface significantly enhanced the electrical signal change of the graphene-based channel, and reduced the recovery time needed to obtain a normal state of equilibrium. In addition, a simple and efficient soft lithographic patterning process was developed via surface energy modification for advanced, graphene-based flexible devices, such as gas sensors. As a proof of concept, we demonstrated the high sensitivity of NO2 gas sensors based on graphene nanosheets. These devices were fabricated using a simple soft-lithographic patterning method, where flexible graphene heaters adjacent to the channel of sensing graphene were utilized to control graphene temperature.

  18. Processing method for chemical cleaning liquid on the secondary side of steam generator

    International Nuclear Information System (INIS)

    Nishihara, Yukio; Inagaki, Yuzo.

    1993-01-01

    Upon processing nitrilotriacetate (NTA), Fe liquid wastes mainly comprising Fe and Cu liquid wastes mainly comprising ethylene diamine and Cu generated upon chemical cleaning on the secondary side of a steam generator, pH of the Fe liquid wastes is lowered to deposit and separate NTA. Then, Fe ions in a filtrates are deposited on a cathode by electrolysis, as well as remaining NTA is decomposed by oxidation at an anode by O 2 gas. Cu liquid wastes are reacted with naphthalene disulfate and Ba ions and the reaction products are separated by deposition as sludges. Remaining Cu ions in the filtrates are deposited on the cathode by electrolysis. With such procedures, concentration of COD(NTA), Fe ions and Cu ions can greatly be reduced. Further, since capacity of the device can easily be increased in this method, a great amount of liquid wastes can be processed in a relatively short period of time. (T.M.)

  19. Highly sensitive methanol chemical sensor based on undoped silver oxide nanoparticles prepared by a solution method

    International Nuclear Information System (INIS)

    Rahman, M.M.; Khan, S.B.; Asiri, A.M.; Jamal, A.; Faisal, M.

    2012-01-01

    We have prepared silver oxide nanoparticles (NPs) by a simple solution method using reducing agents in alkaline medium. The resulting NPs were characterized by UV-vis and FT-IR spectroscopy, X-ray powder diffraction, and field-emission scanning electron microscopy. They were deposited on a glassy carbon electrode to give a sensor with a fast response towards methanol in liquid phase. The sensor also displays good sensitivity and long-term stability, and enhanced electrochemical response. The calibration plot is linear (r 2 = 0.8294) over the 0.12 mM to 0.12 M methanol concentration range. The sensitivity is ∼ 2.65 μAcm -2 mM -1 , and the detection limit is 36.0 μM (at a SNR of 3). We also discuss possible future prospective uses of this metal oxide semiconductor nanomaterial in terms of chemical sensing. (author)

  20. Chemical Methods for the Determination of Soluble and Insoluble Non-Starch Polysaccharides - Review

    Directory of Open Access Journals (Sweden)

    Rodica Căpriţă

    2011-10-01

    Full Text Available Polysaccharides are macromolecules of monosaccharides linked by glycosidic bonds. Non-starch polysaccharides(NSP are principally non-α-glucan polysaccharides of the plant cell wall. They are a heterogeneous group ofpolysaccharides with varying degrees of water solubility, size, and structure. The water insoluble fiber fractioninclude cellulose, galactomannans, xylans, xyloglucans, and lignin, while the water-soluble fibers are the pectins,arabinogalactans, arabinoxylans, and β-(1,3(1,4-D-glucans (β-glucans. Both the enzymatic-gravimetric andenzymatic-chemical methods used for the determination of soluble and insoluble non-starch polysaccharides haveundergone a number of modifications and improvements, most occurring over the last 20 years.

  1. Synthesis and spectroscopic characterization of gold nanobipyramids prepared by a chemical reduction method

    International Nuclear Information System (INIS)

    Ngo, Vo Ke Thanh; Huynh, Trong Phat; Nguyen, Dang Giang; Nguyen, Hoang Phuong Uyen; Lam, Quang Vinh; Huynh, Thanh Dat

    2015-01-01

    Gold nanobipyramids (NBPs) have attracted much attention because they have potential for applications in smart sensing devices, such as medical diagnostic equippments. This is due to the fact that they show more advantageous plasmonic properties than other gold nanostructures. We describe a chemical reduction method for synthesizing NBPs using conventional heating with ascorbic acid reduction and cetyltrimethylamonium bromide (CTAB) + AgNO_3 as capping agents. The product was characterized by ultraviolet–visible spectroscopy (UV–vis), Fourier transmission infrared spectroscopy (FTIR), transmission electron microscopy (TEM), x-ray powder diffraction (XRD). The results showed that gold nanoparticles were formed with bipyramid shape (tip-to-tip distance of 88.4 ± 9.4 nm and base length of 29.9 ± 3.2 nm) and face-centered-cubic crystalline structure. Optimum parameters for preparation of NBPs are also found. (paper)

  2. Synthesis and spectroscopic characterization of gold nanobipyramids prepared by a chemical reduction method

    Science.gov (United States)

    Thanh Ngo, Vo Ke; Phat Huynh, Trong; Giang Nguyen, Dang; Phuong Uyen Nguyen, Hoang; Lam, Quang Vinh; Dat Huynh, Thanh

    2015-12-01

    Gold nanobipyramids (NBPs) have attracted much attention because they have potential for applications in smart sensing devices, such as medical diagnostic equippments. This is due to the fact that they show more advantageous plasmonic properties than other gold nanostructures. We describe a chemical reduction method for synthesizing NBPs using conventional heating with ascorbic acid reduction and cetyltrimethylamonium bromide (CTAB) + AgNO3 as capping agents. The product was characterized by ultraviolet-visible spectroscopy (UV-vis), Fourier transmission infrared spectroscopy (FTIR), transmission electron microscopy (TEM), x-ray powder diffraction (XRD). The results showed that gold nanoparticles were formed with bipyramid shape (tip-to-tip distance of 88.4 ± 9.4 nm and base length of 29.9 ± 3.2 nm) and face-centered-cubic crystalline structure. Optimum parameters for preparation of NBPs are also found.

  3. Microstructures and photocatalytic properties of porous ZnO films synthesized by chemical bath deposition method

    International Nuclear Information System (INIS)

    Wang Huihu; Dong, Shijie; Chang Ying; Zhou Xiaoping; Hu Xinbin

    2012-01-01

    Different porous ZnO film structures on the surface of alumina substrates were prepared through a simple chemical bath deposition method in the methanolic zinc acetate solution. The surface morphology and phase structure of porous ZnO film were determined by scanning electron microscopy (SEM) and X-ray diffraction (XRD), respectively. Both initial zinc acetate concentration and sintering temperature have great impact on the final film structures. With the increase of initial zinc acetate concentration, the porous structures can be finely tuned from circular nest like assemblies composed film into successive nest like film, and finally to globular aggregates composed film. By increasing the sintering temperature, the porous structure of successive nest like film can be further controlled. Furthermore, the crystallinity of photocatalysts also can be greatly improved. The photodegradation results of Methyl Orange revealed that porous ZnO film with successive nest like structure sintered at 500 °C exhibited the highest photocatalytic activity under UV illumination.

  4. PEG capped CaS nanoparticles synthesized by wet chemical co-precipitation method

    Science.gov (United States)

    Rekha, S.; Anila, E. I.

    2018-04-01

    Calcium sulfide (CaS) nanoparticles capped with polyethyleneglycol (PEG) were synthesized using wet chemical co-precipitation method. The structural and optical properties of the prepared sample were studied by X-ray diffractogram (XRD), transmission electron microscopy (TEM), diffuse reflectance spectrum (DRS) and photoluminescence (PL) spectrum. The structure of CaS nanoparticles is cubic as demonstrated by the X-ray powder diffraction (XRD) and selected area electron diffraction (SAED) analysis. TEMimage revealed the spherical morphology of the particles with diameter in the range 15-20 nm. The optical band gap of the prepared sample was determined from the DRS and its value was found to be 4.1 eV. The PL studies showed that the relative intensity of the PEG capped CaS nanoparticles was higher than that of uncapped CaS nanoparticles. The presence of various functional groups in the capped samples were examined by Fourier Transform Infrared (FTIR) spectroscopy.

  5. Size-controlled Synthesis and Characterization of Fe3O4 Nanoparticles by Chemical Coprecipitation Method

    International Nuclear Information System (INIS)

    Chia Chin Hua; Sarani Zakaria; Farahiyan, R.; Liew Tze Khong; Mustaffa Abdullah; Sahrim Ahmad; Nguyen, K.L.

    2008-01-01

    Magnetite (Fe 3 O 4 ) nanoparticles have been synthesized using the chemical coprecipitation method. The Fe 3 O 4 nanoparticles were likely formed via dissolution-recrystallization process. During the precipitation process, ferrihydrite and Fe(OH) 2 particles formed aggregates and followed by the formation of spherical Fe 3 O 4 particles. The synthesized Fe 3 O 4 nanoparticles exhibited superparamagnetic behavior and in single crystal form. The synthesis temperature and the degree of agitation during the precipitation were found to be decisive in controlling the crystallite and particle size of the produced Fe 3 O 4 nanoparticles. Lower temperature and higher degree of agitation were the favorable conditions for producing smaller particle. The magnetic properties (saturation magnetization and coercivity) of the Fe 3 O 4 nanoparticles increased with the particle size. (author)

  6. Fabrication and Characterization of Zinc Sulfide Nanoparticles and Nanocomposites Prepared via a Simple Chemical Precipitation Method

    Directory of Open Access Journals (Sweden)

    Kambiz Hedayati

    2016-07-01

    Full Text Available In this research zinc sulfide (ZnS nanoparticles and nanocomposites powders were prepared by chemical precipitation method using zinc acetate and various sulfur sources. The ZnS nanoparticles were characterized by X-ray diffraction, scanning electron microscopy, ultraviolet-visible and fourier transform infra-red. The structure of nanoparticles was studied using X-ray diffraction pattern. The crystallite size of ZnS nanoparticles was calculated by Debye–Scherrer formula. Morphology of nano-crystals was observed and investigated using the scanning electron microscopy. The grain size of zinc sulfide nanoparticles were in suitable agreement with the crystalline size calculated by X-ray diffraction results. The optical properties of particles were studied with ultraviolet-visible absorption spectrum.

  7. Studies of coupled chemical and catalytic coal conversion methods. Tenth quarterly report, January--March 1990

    Energy Technology Data Exchange (ETDEWEB)

    Stock, L.M.

    1990-12-31

    This report concerns our research on base-catalyzed coal solubilization and a new approach for hydrogen addition. The work on base-catalyzed, chemical solubilization is continuing. this report is focused on the hydrogenation research. Specifically it deals with the use of arene chromium carbonyl complexes as reagents for the addition of dideuterium to coal molecules. In one phase of the work, he has established that the aromatic hydrocarbons in a representative coal liquid can be converted in very good yield to arene chromium carbonyl compounds. In a second phase of the work directly related to our objective of improved methods for catalytic hydrogenation, he has established that the aromatic constituents of the same coal liquid add dideuterium in the presence of added napththalene chromium carbonyl.

  8. Method and apparatus for obtaining enhanced production rate of thermal chemical reactions

    Science.gov (United States)

    Tonkovich, Anna Lee Y [Pasco, WA; Wang, Yong [Richland, WA; Wegeng, Robert S [Richland, WA; Gao, Yufei [Kennewick, WA

    2003-04-01

    The present invention is a method and apparatus (vessel) for providing a heat transfer rate from a reaction chamber through a wall to a heat transfer chamber substantially matching a local heat transfer rate of a catalytic thermal chemical reaction. The key to the invention is a thermal distance defined on a cross sectional plane through the vessel inclusive of a heat transfer chamber, reaction chamber and a wall between the chambers. The cross sectional plane is perpendicular to a bulk flow direction of the reactant stream, and the thermal distance is a distance between a coolest position and a hottest position on the cross sectional plane. The thermal distance is of a length wherein the heat transfer rate from the reaction chamber to the heat transfer chamber substantially matches the local heat transfer rate.

  9. Macrokinetics of carbon nanotubes synthesis by the chemical vapor deposition method

    Science.gov (United States)

    Rukhov, Artem; Dyachkova, Tatyana; Tugolukov, Evgeny; Besperstova, Galina

    2017-11-01

    A new approach to studying and developing basic processes which take place on the surface of a metal catalyst during the thermal decomposition of carbonaceous substances in the carbon nanotubes synthesis by the chemical vapor deposition method was proposed. In addition, an analysis was made of the interrelationships between these thermal, diffusion, hydrodynamic and other synthesis processes. A strong effect of the catalyst regeneration stage on the stage of nanotube formation has been shown. Based on the developed approach, a mathematical model was elaborated. Comparison of the calculation and the experiment carried out with the NiO-MgO catalyst at propane flow rate of 50 mL/min (standard conditions) and ethanol flow rate 0.3 mL/min (liq.) has revealed a discrepancy of less than 10%.

  10. Chemical method of labelling proteins with the radionuclides of technetium at physiological condition

    International Nuclear Information System (INIS)

    Wong, D.W.

    1983-01-01

    A novel rapid chemical method of labeling plasma proteins, other compounds and/or substances containing protein with radionuclides of technetium such as sup(95m)Tc, sup(99m)Tc or sup(99)Tc at physiologic pH 7.4 condition, producing a sterile non-pyrogenic radioactive tracer material suitable for biological and medical uses. These radiolabeled protein substances are not denatured by the labeling process but retain their natural physiological and immunological properties. This novel labeling technique provides a simple and rapid means of labeling plasma proteins such as human serum albumin, fibrinogen, antibodies, hormones and enzymes with sup(95m)Tc or sup(99m)Tc for scintigraphic imaging which may allow visualization of thrombi, emboli, myocardial infarcts, infectious lesions or tumors

  11. Method for the Collection, Gravimetric and Chemical Analysis of Nonvolatile Residue (NVR) on Surfaces

    Science.gov (United States)

    Gordon, Keith; Rutherford, Gugu; Aranda, Denisse

    2017-01-01

    Nonvolatile residue (NVR), sometimes referred to as molecular contamination is the term used for the total composition of the inorganic and high boiling point organic components in particulates and molecular films deposited on critical surfaces surrounding space structures, with the particulate and NVR contamination originating primarily from pre-launch operations. The "nonvolatile" suggestion from the terminology NVR implies that the collected residue will not experience much loss under ambient conditions. NVR has been shown to have a dramatic impact on the ability to perform optical measurements from platforms based in space. Such contaminants can be detected early by the controlled application of various detection techniques and contamination analyses. Contamination analyses are the techniques used to determine if materials, components, and subsystems can be expected to meet the performance requirements of a system. Of particular concern is the quantity of NVR contaminants that might be deposited on critical payload surfaces from these sources. Subsequent chemical analysis of the contaminant samples by infrared spectroscopy and gas chromatography mass spectrometry identifies the components, gives semi-quantitative estimates of contaminant thickness, indicates possible sources of the NVR, and provides guidance for effective cleanup procedures. In this report, a method for the collection and determination of the mass of NVR was generated by the authors at NASA Langley Research Center. This report describes the method developed and implemented for collecting NVR contaminants, and procedures for gravimetric and chemical analysis of the residue obtained. The result of this NVR analysis collaboration will help pave the way for Langley's ability to certify flight hardware outgassing requirements in support of flight projects such as Stratospheric Aerosol and Gas Experiment III (SAGE III), Clouds and the Earth's Radiant Energy System (CERES), Materials International

  12. Occurrence of two-photon absorption saturation in Ag nanocolloids, prepared by chemical reduction method

    Energy Technology Data Exchange (ETDEWEB)

    Rahulan, K. Mani, E-mail: krahul.au@gmail.com [Department of Physics, Anna University, Chennai (India); Ganesan, S. [Department of Physics, Anna University, Chennai (India); Aruna, P., E-mail: aruna@annauniv.edu [Department of Physics, Anna University, Chennai (India)

    2012-09-01

    Highlights: Black-Right-Pointing-Pointer Ag nanocolloids were synthesized via chemical reduction method. Black-Right-Pointing-Pointer The molecules of PVP play an important role in growth and agglomeration of silver nanocolloids. Black-Right-Pointing-Pointer Saturation behaviour followed by two photon absorption was responsible for good optical limiting characteristics in these nanocolloids. Black-Right-Pointing-Pointer The nonlinear optical parameters calculated from the data showed that these materials could be used as efficient optical limiters. - Abstract: Silver nanocolloids stabilized with polyvinyl pyrrolidone (PVP) have been prepared from (AgNO{sub 3}) by a chemical reduction method, involving the intermediate preparation of (Ag{sub 2}O) colloidal dispersions in the presence of sodium dodecycle sulfate as a surfactant and formaldehyde as reducing agent. The molecules of PVP play an important role in growth and agglomeration of silver nanocolloids. The formation of Ag nanocolloids was studied from the UV-vis absorption characteristics. An energy dispersive X-ray (EDX) spectrum and X-ray diffraction peak of the nanoparticles showed the highly crystalline nature of silver structure. The particle size was found to be 40 nm as analyzed from Field emission scanning electron microscopy (FESEM). The nonlinear optical and optical limiting properties of these nanoparticle dispersions were studied by using the Z-scan technique at 532 nm. Experimental results show that the Ag nanocolloids possess strong optical limiting effect, originated from absorption saturation followed by two-photon mechanism. The data show that Ag nanocolloids have great potential for nonlinear optical devices.

  13. Learnings from LCA-based methods: should chemicals in food packaging be a priority focus to protect human health?

    DEFF Research Database (Denmark)

    Ernstoff, Alexi; Stylianou, Katerina S.; Fantke, Peter

    2017-01-01

    Given the scale and variety of human health damage (HHD) caused by food systems, prioritization methods are urgently needed. In this study HHD is estimated for case studies on red meat and sugary sweetened beverages (SSB) packaged in high-impact polystyrene (HIPS) due to various relevant health...... impacts. Specifically, we aim to asses if chemicals in food packaging are important to HHD in a life cycle context. The functional unit is "daily consumption of a packaged food per person in the United States." Method developments focus on human toxicity characterization of chemicals migrating from...... packaging into food. Chemicals and their concentrations in HIPS were identified from regulatory lists. A new high-throughput model estimated migration into food, depending on properties of chemicals, packaging, food, and scenario, and HHD was extrapolated following LCA characterization methods. An LCA...

  14. Investigation of the fluidized bed-chemical vapor deposition (FBCVD) process using CFD-DEM method

    International Nuclear Information System (INIS)

    Liu Malin; Liu Rongzheng; Wen Yuanyun; Liu Bing; Shao Youlin

    2014-01-01

    The CFD-DEM-CVD multiscale coupling simulation concept was proposed based on the mass/momentum/energy transfer involved in the FB-CVD process. The pyrolysis process of the reaction gas in the spouted bed can be simulated by CFD method, then the concentration field and velocity field can be extracted and coupled with the particle movement behavior which can be simulated by DEM. Particle deposition process can be described by the CVD model based on particle position, velocity and neighboring gas concentration. This multiscale coupling method can be implemented in the Fluent@-EDEM@ software with their UDF (User Definition Function) and API (Application Programming Interface). Base on the multiscale coupling concept, the criterion for evaluating FB-CVD process is given. At first, the volume in the coating furnace is divided into two parts (active coating area and non-active coating area) based on simulation results of chemical pyrolysis process. Then the residence time of all particles in the active coating area can be obtained using the CFD-DEM simulation method. The residence time distribution can be used as a criterion for evaluating the gas-solid contact efficiency and operation performance of the coating furnace. At last different coating parameters of the coating furnace are compared based on the proposed criterion. And also, the future research emphasis is discussed. (author)

  15. Chemical and isotopic methods for characterization of pollutant sources in rain water

    International Nuclear Information System (INIS)

    Verma, M.P.

    1996-01-01

    The acid rain formation is related with industrial pollution. An isotopic and chemical study of the spatial and temporary distribution of the acidity in the rain gives information about the acidity source. The predominant species in the acid rain are nitrates and sulfates. For the rain monitoring is required the determination of the anion species such as HCO 3 , Cl, SO 4 , NO 3 and p H. So it was analyzed the cations Na + , K + , Ca 2+ and Mg 2+ to determine the quality analysis. All of them species can be determined with enough accuracy, except HCO 3 by modern equipment such as, liquid chromatograph, atomic absorption, etc. The HCO 3 concentration is determined by traditional methods like acid-base titration. This work presents the fundamental concepts of the titration method for samples with low alkalinity (carbonic species), for rain water. There is presented a general overview over the isotopic methods for the characterization of the origin of pollutant sources in the rain. (Author)

  16. The T-TEL Method for Assessing Water, Sediment, and Chemical Connectivity

    Science.gov (United States)

    Ali, Genevieve; Oswald, Claire; Spence, Christopher; Wellen, Christopher

    2018-02-01

    The concept of connectivity has been the subject of a great deal of recent research and provided new insights and breakthroughs on runoff generation processes and watershed biogeochemistry. However, a consensus definition and cohesive mathematical framework that would permit the consistent quantification of hydrologic connectivity, the examination of the interrelationships between water and material (e.g., sediment and chemicals) connectivity, or rigorous study intercomparison, have not been presented by the water resource community. Building on previous conceptualizations and site-specific or process-specific metrics, this paper aimed to review the current state of science on hydrologic connectivity and its role in water-mediated connectivity of material such as solutes and sediment before introducing a conceptual and a mathematical connectivity assessment framework. These frameworks rely on the quantification of Time scales, Thresholds, Excesses and Losses related to water and water-mediated material transport dynamics and are referred to as the T-TEL method. Through a small case study, we show how the T-TEL method allows a wide range of properties to be quantified, namely the occurrence, frequency, duration, magnitude, and spatial extent of water and water-mediated material connectivity. We also propose a research agenda to refine the T-TEL method and ensure its usefulness for facilitating the research and management of connectivity in pristine and human-impacted landscapes.

  17. Faraday effect of polycrystalline bismuth iron garnet thin film prepared by mist chemical vapor deposition method

    International Nuclear Information System (INIS)

    Yao, Situ; Kamakura, Ryosuke; Murai, Shunsuke; Fujita, Koji; Tanaka, Katsuhisa

    2017-01-01

    We have synthesized polycrystalline thin film composed of a single phase of metastable bismuth iron garnet, Bi_3Fe_5O_1_2, on a fused silica substrate, one of the most widely utilized substrates in the solid-state electronics, by using mist chemical vapor deposition (mist CVD) method. The phase purity and stoichiometry are confirmed by X-ray diffraction and Rutherford backscattering spectrometry. The resultant thin film shows a small surface roughness of 3.251 nm. The saturation magnetization at room temperature is 1200 G, and the Faraday rotation angle at 633 nm reaches −5.2 deg/μm. Both the magnetization and the Faraday rotation angles are somewhat higher than those of polycrystalline BIG thin films prepared by other methods. - Highlights: • Thin film of polycrystalline Bi_3Fe_5O_1_2 was prepared by the mist CVD method. • Optimized conditions were found for the synthesis of single phase of Bi_3Fe_5O_1_2. • The Faraday rotation angle at 633 nm is –5.2 deg/μm at room temperature. • The Faraday rotation is interpreted by the electronic transitions of Fe"3"+ ions.

  18. Faraday effect of polycrystalline bismuth iron garnet thin film prepared by mist chemical vapor deposition method

    Energy Technology Data Exchange (ETDEWEB)

    Yao, Situ; Kamakura, Ryosuke; Murai, Shunsuke; Fujita, Koji; Tanaka, Katsuhisa, E-mail: tanaka@dipole7.kuic.kyoto-u.ac.jp

    2017-01-15

    We have synthesized polycrystalline thin film composed of a single phase of metastable bismuth iron garnet, Bi{sub 3}Fe{sub 5}O{sub 12}, on a fused silica substrate, one of the most widely utilized substrates in the solid-state electronics, by using mist chemical vapor deposition (mist CVD) method. The phase purity and stoichiometry are confirmed by X-ray diffraction and Rutherford backscattering spectrometry. The resultant thin film shows a small surface roughness of 3.251 nm. The saturation magnetization at room temperature is 1200 G, and the Faraday rotation angle at 633 nm reaches −5.2 deg/μm. Both the magnetization and the Faraday rotation angles are somewhat higher than those of polycrystalline BIG thin films prepared by other methods. - Highlights: • Thin film of polycrystalline Bi{sub 3}Fe{sub 5}O{sub 12} was prepared by the mist CVD method. • Optimized conditions were found for the synthesis of single phase of Bi{sub 3}Fe{sub 5}O{sub 12}. • The Faraday rotation angle at 633 nm is –5.2 deg/μm at room temperature. • The Faraday rotation is interpreted by the electronic transitions of Fe{sup 3+} ions.

  19. Semiempirical Quantum-Chemical Orthogonalization-Corrected Methods: Benchmarks for Ground-State Properties.

    Science.gov (United States)

    Dral, Pavlo O; Wu, Xin; Spörkel, Lasse; Koslowski, Axel; Thiel, Walter

    2016-03-08

    The semiempirical orthogonalization-corrected OMx methods (OM1, OM2, and OM3) go beyond the standard MNDO model by including additional interactions in the electronic structure calculation. When augmented with empirical dispersion corrections, the resulting OMx-Dn approaches offer a fast and robust treatment of noncovalent interactions. Here we evaluate the performance of the OMx and OMx-Dn methods for a variety of ground-state properties using a large and diverse collection of benchmark sets from the literature, with a total of 13035 original and derived reference data. Extensive comparisons are made with the results from established semiempirical methods (MNDO, AM1, PM3, PM6, and PM7) that also use the NDDO (neglect of diatomic differential overlap) integral approximation. Statistical evaluations show that the OMx and OMx-Dn methods outperform the other methods for most of the benchmark sets.

  20. Toxicity assessment of industrial chemicals and airborne contaminants: transition from in vivo to in vitro test methods: a review.

    Science.gov (United States)

    Bakand, S; Winder, C; Khalil, C; Hayes, A

    2005-12-01

    Exposure to occupational and environmental contaminants is a major contributor to human health problems. Inhalation of gases, vapors, aerosols, and mixtures of these can cause a wide range of adverse health effects, ranging from simple irritation to systemic diseases. Despite significant achievements in the risk assessment of chemicals, the toxicological database, particularly for industrial chemicals, remains limited. Considering there are approximately 80,000 chemicals in commerce, and an extremely large number of chemical mixtures, in vivo testing of this large number is unachievable from both economical and practical perspectives. While in vitro methods are capable of rapidly providing toxicity information, regulatory agencies in general are still cautious about the replacement of whole-animal methods with new in vitro techniques. Although studying the toxic effects of inhaled chemicals is a complex subject, recent studies demonstrate that in vitro methods may have significant potential for assessing the toxicity of airborne contaminants. In this review, current toxicity test methods for risk evaluation of industrial chemicals and airborne contaminants are presented. To evaluate the potential applications of in vitro methods for studying respiratory toxicity, more recent models developed for toxicity testing of airborne contaminants are discussed.

  1. Sensitivity of ab Initio vs Empirical Methods in Computing Structural Effects on NMR Chemical Shifts for the Example of Peptides.

    Science.gov (United States)

    Sumowski, Chris Vanessa; Hanni, Matti; Schweizer, Sabine; Ochsenfeld, Christian

    2014-01-14

    The structural sensitivity of NMR chemical shifts as computed by quantum chemical methods is compared to a variety of empirical approaches for the example of a prototypical peptide, the 38-residue kaliotoxin KTX comprising 573 atoms. Despite the simplicity of empirical chemical shift prediction programs, the agreement with experimental results is rather good, underlining their usefulness. However, we show in our present work that they are highly insensitive to structural changes, which renders their use for validating predicted structures questionable. In contrast, quantum chemical methods show the expected high sensitivity to structural and electronic changes. This appears to be independent of the quantum chemical approach or the inclusion of solvent effects. For the latter, explicit solvent simulations with increasing number of snapshots were performed for two conformers of an eight amino acid sequence. In conclusion, the empirical approaches neither provide the expected magnitude nor the patterns of NMR chemical shifts determined by the clearly more costly ab initio methods upon structural changes. This restricts the use of empirical prediction programs in studies where peptide and protein structures are utilized for the NMR chemical shift evaluation such as in NMR refinement processes, structural model verifications, or calculations of NMR nuclear spin relaxation rates.

  2. Study on the identification method of chemical warfare agents with spectroscopy of neutron induced γ rays

    International Nuclear Information System (INIS)

    Liu Boxue; Li Yun; Li Xiangbao

    1996-01-01

    The paper briefly describes some non-destructive verification technologies of chemical warfare agents in-site, and some application of neutron induced gamma ray analysis, such as multi-elements analysis of coal, hidden explosive detection and identification of chemical agents. It also describes some problems in developing the portable isotopic neutron spectroscopy for non-destructive evaluation of chemical warfare agents

  3. High-Performance Black Multicrystalline Silicon Solar Cells by a Highly Simplified Metal-Catalyzed Chemical Etching Method

    KAUST Repository

    Ying, Zhiqin

    2016-05-20

    A wet-chemical surface texturing technique, including a two-step metal-catalyzed chemical etching (MCCE) and an extra alkaline treatment, has been proven as an efficient way to fabricate high-efficiency black multicrystalline (mc) silicon solar cells, whereas it is limited by the production capacity and the cost cutting due to the complicated process. Here, we demonstrated that with careful control of the composition in etching solution, low-aspect-ratio bowl-like nanostructures with atomically smooth surfaces could be directly achieved by improved one-step MCCE and with no posttreatment, like alkali solution. The doublet surface texture of implementing this nanobowl structure upon the industrialized acidic-textured surface showed concurrent improvement in optical and electrical properties for realizing 18.23% efficiency mc-Si solar cells (156 mm × 156 mm), which is sufficiently higher than 17.7% of the solely acidic-textured cells in the same batch. The one-step MCCE method demonstrated in this study may provide a cost-effective way to manufacture high-performance mc-Si solar cells for the present photovoltaic industry. © 2016 IEEE.

  4. The application of infrared chemical imaging to the detection and enhancement of latent fingerprints: method optimization and further findings.

    Science.gov (United States)

    Tahtouh, Mark; Despland, Pauline; Shimmon, Ronald; Kalman, John R; Reedy, Brian J

    2007-09-01

    Fourier transform infrared (FTIR) chemical imaging allows the collection of fingerprint images from backgrounds that have traditionally posed problems for conventional fingerprint detection methods. In this work, the suitability of this technique for the imaging of fingerprints on a wider range of difficult surfaces (including polymer banknotes, various types of paper, and aluminum drink cans) has been tested. For each new surface, a systematic methodology was employed to optimize settings such as spectral resolution, number of scans, and pixel aggregation in order to reduce collection time and file-size without compromising spatial resolution and the quality of the final fingerprint image. The imaging of cyanoacrylate-fumed fingerprints on polymer banknotes has been improved, with shorter collection times for larger image areas. One-month-old fingerprints on polymer banknotes have been successfully fumed and imaged. It was also found that FTIR chemical imaging gives high quality images of cyanoacrylate-fumed fingerprints on aluminum drink cans, regardless of the printed background. Although visible and UV light sources do not yield fingerprint images of the same quality on difficult, nonporous backgrounds, in many cases they can be used to locate a fingerprint prior to higher quality imaging by the FTIR technique. Attempts to acquire FTIR images of fingerprints on paper-based porous surfaces that had been treated with established reagents such as ninhydrin were all unsuccessful due to the swamping effect of the cellulose constituents of the paper.

  5. Accelerating finite-rate chemical kinetics with coprocessors: Comparing vectorization methods on GPUs, MICs, and CPUs

    Science.gov (United States)

    Stone, Christopher P.; Alferman, Andrew T.; Niemeyer, Kyle E.

    2018-05-01

    Accurate and efficient methods for solving stiff ordinary differential equations (ODEs) are a critical component of turbulent combustion simulations with finite-rate chemistry. The ODEs governing the chemical kinetics at each mesh point are decoupled by operator-splitting allowing each to be solved concurrently. An efficient ODE solver must then take into account the available thread and instruction-level parallelism of the underlying hardware, especially on many-core coprocessors, as well as the numerical efficiency. A stiff Rosenbrock and a nonstiff Runge-Kutta ODE solver are both implemented using the single instruction, multiple thread (SIMT) and single instruction, multiple data (SIMD) paradigms within OpenCL. Both methods solve multiple ODEs concurrently within the same instruction stream. The performance of these parallel implementations was measured on three chemical kinetic models of increasing size across several multicore and many-core platforms. Two separate benchmarks were conducted to clearly determine any performance advantage offered by either method. The first benchmark measured the run-time of evaluating the right-hand-side source terms in parallel and the second benchmark integrated a series of constant-pressure, homogeneous reactors using the Rosenbrock and Runge-Kutta solvers. The right-hand-side evaluations with SIMD parallelism on the host multicore Xeon CPU and many-core Xeon Phi co-processor performed approximately three times faster than the baseline multithreaded C++ code. The SIMT parallel model on the host and Phi was 13%-35% slower than the baseline while the SIMT model on the NVIDIA Kepler GPU provided approximately the same performance as the SIMD model on the Phi. The runtimes for both ODE solvers decreased significantly with the SIMD implementations on the host CPU (2.5-2.7 ×) and Xeon Phi coprocessor (4.7-4.9 ×) compared to the baseline parallel code. The SIMT implementations on the GPU ran 1.5-1.6 times faster than the baseline

  6. COMPARATIVE STUDY OF CHEMICAL COMPOSITION, PHYSICO-CHEMICAL AND ANTIOXIDANT PROPERTIES OF OILS EXTRACTED BY TRADITIONAL AND HEXANE METHODS FROM TERMINALIA CATAPPA L. KERNELS

    Directory of Open Access Journals (Sweden)

    Bérenger A. L. Ladele

    2017-10-01

    Full Text Available The comparative study of physico-chemical characteristics of Terminalia catappa L. kernel oils extracted by two methods has been done. The oil yields were 28.13 % and 61.78 % respectively for traditional and hexane methods and the fatty acid profiles showed palmitic acid (40.79 % and 40.03 % respectively oleic acid (25.55 % and 26.09 % respectively, linoleic acid (26.72 % and 26.64 % respectively and stearic acid (4.35 % and 4.49 % respectively as major components. The oils extracted by the two ways showed similar physico-chemical properties, good calorific values and non-toxicity against Artemia salina L. Oil obtained by traditional method exhibited more antioxidant capacity (1.40 than the hexane one (0.15. This traditional method helps to extract 45 % of the total oil. It gives oil free of organic solvent, with good physico-chemical properties that could be useful as edible oil and for industrial applications.

  7. Evaluation on ultrasonic examination methods applied to Ni-base alloy weld including cracks due to stress corrosion cracking found in BWR reactor internal

    International Nuclear Information System (INIS)

    Aoki, Takayuki; Kobayashi, Hiroyuki; Higuchi, Shinichi; Shimizu, Sadato

    2005-01-01

    A Ni-base alloy weld, including cracks due to stress corrosion cracking found in the reactor internal of the oldest BWR in Japan, Tsuruga unit 1, in 1999, was examined by three (3) types of UT method. After this examination, a depth of each crack was confirmed by carrying out a little excavation with a grinder and PT examination by turns until each crack disappeared. Then, the depth measured by the former method was compared with the one measured by the latter method. In this fashion, performances of the UT methods were verified. As a result, a combination of the three types of UT method was found to meet the acceptance criteria given by ASME Sec.XI Appendix VIII, Performance Demonstration for Ultrasonic Examination Systems-Supplement 6. In this paper, the results of the UT examination described above and their evaluation are discussed. (author)

  8. Methods used to characterize the chemical composition and biological activity of environmental waters throughout the United States, 2012-14

    Science.gov (United States)

    Romanok, Kristin M.; Reilly, Timothy J.; Barber, Larry B.; Boone, J. Scott; Buxton, Herbert T.; Foreman, William T.; Furlong, Edward T.; Hladik, Michelle; Iwanowicz, Luke R.; Journey, Celeste A.; Kolpin, Dana W.; Kuivila, Kathryn; Loftin, Keith A.; Mills, Marc A.; Meyer, Michael T.; Orlando, James L.; Smalling, Kelly L.; Villeneuve, Daniel L.; Bradley, Paul M.

    2017-03-22

    A vast array of chemical compounds are in wide commercial use in the United States, and the potential ecological and human-health effect of exposure to chemical mixtures has been identified as a high priority in environment health science. Awareness of the potential effects of low-level chemical exposures is rising. The U.S. Geological Survey, in cooperation with the U.S. Environmental Protection Agency, conducted a study in which samples were collected from 38 streams in 25 States to provide an overview of contaminants found in stream water across the Nation. Additionally, biological screening assays were used to help determine any potential ecological and human-health effects of these chemical mixtures and to prioritize target chemicals for future toxicological studies. This report describes the site locations and the sampling and analytical methods and quality-assurance procedures used in the study.

  9. Four chemical methods of porcelain conditioning and their influence over bond strength and surface integrity

    Science.gov (United States)

    Stella, João Paulo Fragomeni; Oliveira, Andrea Becker; Nojima, Lincoln Issamu; Marquezan, Mariana

    2015-01-01

    OBJECTIVE: To assess four different chemical surface conditioning methods for ceramic material before bracket bonding, and their impact on shear bond strength and surface integrity at debonding. METHODS: Four experimental groups (n = 13) were set up according to the ceramic conditioning method: G1 = 37% phosphoric acid etching followed by silane application; G2 = 37% liquid phosphoric acid etching, no rinsing, followed by silane application; G3 = 10% hydrofluoric acid etching alone; and G4 = 10% hydrofluoric acid etching followed by silane application. After surface conditioning, metal brackets were bonded to porcelain by means of the Transbond XP system (3M Unitek). Samples were submitted to shear bond strength tests in a universal testing machine and the surfaces were later assessed with a microscope under 8 X magnification. ANOVA/Tukey tests were performed to establish the difference between groups (α= 5%). RESULTS: The highest shear bond strength values were found in groups G3 and G4 (22.01 ± 2.15 MPa and 22.83 ± 3.32 Mpa, respectively), followed by G1 (16.42 ± 3.61 MPa) and G2 (9.29 ± 1.95 MPa). As regards surface evaluation after bracket debonding, the use of liquid phosphoric acid followed by silane application (G2) produced the least damage to porcelain. When hydrofluoric acid and silane were applied, the risk of ceramic fracture increased. CONCLUSIONS: Acceptable levels of bond strength for clinical use were reached by all methods tested; however, liquid phosphoric acid etching followed by silane application (G2) resulted in the least damage to the ceramic surface. PMID:26352845

  10. Designing Focused Chemical Libraries Enriched in Protein-Protein Interaction Inhibitors using Machine-Learning Methods

    Science.gov (United States)

    Reynès, Christelle; Host, Hélène; Camproux, Anne-Claude; Laconde, Guillaume; Leroux, Florence; Mazars, Anne; Deprez, Benoit; Fahraeus, Robin; Villoutreix, Bruno O.; Sperandio, Olivier

    2010-01-01

    Protein-protein interactions (PPIs) may represent one of the next major classes of therapeutic targets. So far, only a minute fraction of the estimated 650,000 PPIs that comprise the human interactome are known with a tiny number of complexes being drugged. Such intricate biological systems cannot be cost-efficiently tackled using conventional high-throughput screening methods. Rather, time has come for designing new strategies that will maximize the chance for hit identification through a rationalization of the PPI inhibitor chemical space and the design of PPI-focused compound libraries (global or target-specific). Here, we train machine-learning-based models, mainly decision trees, using a dataset of known PPI inhibitors and of regular drugs in order to determine a global physico-chemical profile for putative PPI inhibitors. This statistical analysis unravels two important molecular descriptors for PPI inhibitors characterizing specific molecular shapes and the presence of a privileged number of aromatic bonds. The best model has been transposed into a computer program, PPI-HitProfiler, that can output from any drug-like compound collection a focused chemical library enriched in putative PPI inhibitors. Our PPI inhibitor profiler is challenged on the experimental screening results of 11 different PPIs among which the p53/MDM2 interaction screened within our own CDithem platform, that in addition to the validation of our concept led to the identification of 4 novel p53/MDM2 inhibitors. Collectively, our tool shows a robust behavior on the 11 experimental datasets by correctly profiling 70% of the experimentally identified hits while removing 52% of the inactive compounds from the initial compound collections. We strongly believe that this new tool can be used as a global PPI inhibitor profiler prior to screening assays to reduce the size of the compound collections to be experimentally screened while keeping most of the true PPI inhibitors. PPI-HitProfiler is

  11. Designing focused chemical libraries enriched in protein-protein interaction inhibitors using machine-learning methods.

    Directory of Open Access Journals (Sweden)

    Christelle Reynès

    2010-03-01

    Full Text Available Protein-protein interactions (PPIs may represent one of the next major classes of therapeutic targets. So far, only a minute fraction of the estimated 650,000 PPIs that comprise the human interactome are known with a tiny number of complexes being drugged. Such intricate biological systems cannot be cost-efficiently tackled using conventional high-throughput screening methods. Rather, time has come for designing new strategies that will maximize the chance for hit identification through a rationalization of the PPI inhibitor chemical space and the design of PPI-focused compound libraries (global or target-specific. Here, we train machine-learning-based models, mainly decision trees, using a dataset of known PPI inhibitors and of regular drugs in order to determine a global physico-chemical profile for putative PPI inhibitors. This statistical analysis unravels two important molecular descriptors for PPI inhibitors characterizing specific molecular shapes and the presence of a privileged number of aromatic bonds. The best model has been transposed into a computer program, PPI-HitProfiler, that can output from any drug-like compound collection a focused chemical library enriched in putative PPI inhibitors. Our PPI inhibitor profiler is challenged on the experimental screening results of 11 different PPIs among which the p53/MDM2 interaction screened within our own CDithem platform, that in addition to the validation of our concept led to the identification of 4 novel p53/MDM2 inhibitors. Collectively, our tool shows a robust behavior on the 11 experimental datasets by correctly profiling 70% of the experimentally identified hits while removing 52% of the inactive compounds from the initial compound collections. We strongly believe that this new tool can be used as a global PPI inhibitor profiler prior to screening assays to reduce the size of the compound collections to be experimentally screened while keeping most of the true PPI inhibitors. PPI

  12. Designing focused chemical libraries enriched in protein-protein interaction inhibitors using machine-learning methods.

    Science.gov (United States)

    Reynès, Christelle; Host, Hélène; Camproux, Anne-Claude; Laconde, Guillaume; Leroux, Florence; Mazars, Anne; Deprez, Benoit; Fahraeus, Robin; Villoutreix, Bruno O; Sperandio, Olivier

    2010-03-05

    Protein-protein interactions (PPIs) may represent one of the next major classes of therapeutic targets. So far, only a minute fraction of the estimated 650,000 PPIs that comprise the human interactome are known with a tiny number of complexes being drugged. Such intricate biological systems cannot be cost-efficiently tackled using conventional high-throughput screening methods. Rather, time has come for designing new strategies that will maximize the chance for hit identification through a rationalization of the PPI inhibitor chemical space and the design of PPI-focused compound libraries (global or target-specific). Here, we train machine-learning-based models, mainly decision trees, using a dataset of known PPI inhibitors and of regular drugs in order to determine a global physico-chemical profile for putative PPI inhibitors. This statistical analysis unravels two important molecular descriptors for PPI inhibitors characterizing specific molecular shapes and the presence of a privileged number of aromatic bonds. The best model has been transposed into a computer program, PPI-HitProfiler, that can output from any drug-like compound collection a focused chemical library enriched in putative PPI inhibitors. Our PPI inhibitor profiler is challenged on the experimental screening results of 11 different PPIs among which the p53/MDM2 interaction screened within our own CDithem platform, that in addition to the validation of our concept led to the identification of 4 novel p53/MDM2 inhibitors. Collectively, our tool shows a robust behavior on the 11 experimental datasets by correctly profiling 70% of the experimentally identified hits while removing 52% of the inactive compounds from the initial compound collections. We strongly believe that this new tool can be used as a global PPI inhibitor profiler prior to screening assays to reduce the size of the compound collections to be experimentally screened while keeping most of the true PPI inhibitors. PPI-HitProfiler is

  13. Conversion of chemical energy in an explosive by a magnetohydrodynamic method

    International Nuclear Information System (INIS)

    Lebedev, E.F.; Ostashev, V.E.; Svetsov, G.A.

    1983-01-01

    In this paper, the authors examine different methods for realizing the MHD method for converting chemical energy of a condensed explosive into pulsed electrical energy. It is shown that explosive MHD generators, which are compact sources of powerful pulses of electrical energy, are characterized by their relative simplicity, autonomy and maneuverability of firing and they are capable of operating in the frequency-periodic mode. A number of projects have been proposed for explosive MHD generators in the megajoule range. Practical experience has been gained in creating frequency-periodic action generators as well as autonomous setups using superconducting magnetic systems. The increase in the operational efficiency of an explosive MHD generator is primarily related to increasing the magnetic Reynolds number of the flow, which can be attained, in particular, by using different schemes for accumulating the energy of the explosion. The use of a metallic liner, which expands under the pressure of the detonation products, in an explosive MHD generator is, in the practical sense, apparently hopeless. The general information available on the parameters and properties of explosive MHD generators gives a basis for concluding that this generator is a promising source of powerful energy pulses. In a certain range of parameters, it can be an alternative to the use of conventional high-energy pulse devices

  14. Evaluation of Antioxidant Activities of Some Small Fruits Containing Anthocyanins Using Electrochemical and Chemical Methods

    Directory of Open Access Journals (Sweden)

    Adina Căta

    2016-06-01

    Full Text Available The objective of this work was to estimate the antioxidant capacity of some fruits extracts containing anthocyanins (strawberry, raspberry, elderberry, mulberry, blackberry, bilberry, black and red currant using an electrochemical technique and three classical chemical methods based on reaction between antioxidants and a chromogen compound. evaluation of antioxidant activities of extracts was performed by using FRAP (ferric reducing/antioxidant capacity, ABTS (2,2’-azinobis[3-ethylbenzothiazoline-6-sulphonate] and DPPH (2,2-diphenyl-1-picrylhydrazyl assays. Antioxidant activities of the extracts were correlated with their content of monomeric anthocyanins and total phenolics. Good correlations were obtained especially between antioxidant activities and total phenolics content. Cyclic voltammetry was used for the evaluation of overall reducing capacity of the extracts using a glassy carbon electrode. Reducing capacity of selected fruits extracts was assessed based on the half-peak potential (E1/2 of the first oxidation peak. The oxidation potentials characterized by E1/2 value were not correlated with the antioxidant activities evaluated by the classical methods. This work is licensed under a Creative Commons Attribution 4.0 International License.

  15. A Chemical Eight Group Separation Method for Routine Use in Gamma Spectrometric Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Samsahl, K

    1961-04-15

    A method for the separation of chemical elements in 8 groups suitable for gamma spectrometric analysis has been developed. One group of elements is separated by distillation during dissolution of the sample. The other groups are obtained by means of short ion exchange columns coupled in series An anion exchange column saturated with chloride ions separates chloride complexes, peroxides and other anions from a 3-n HCl + 0.3 % H{sub 2}O{sub 2} sample solution. Some of the chloride complexes are eluted with 0.1-n HCl + 0.3 % H{sub 2}O{sub 2} and subsequently adsorbed as cations on a cation exchange column in hydrogen form. A few eluted elements which do not form cations in this case are found in the effluent. Elements passing the anion exchange column in chloride form without adsorption are separated from a H{sub 2}O solution as citrate complexes, hydroxides, cations and hexametaphosphate complexes. This is done by coupling in series two anion exchange columns subsequently in citrate and hydroxide form and followed by a cation exchanger in sodium form. A mixed bed column ends the series. The behaviour in the separation series of most elements forming gamma emitting isotopes with half lives exceeding 10 minutes on irradiation with thermal neutrons has been studied. The method has been used, routinely for one year.

  16. Vertically aligned carbon nanotube growth by pulsed laser deposition and thermal chemical vapor deposition methods

    International Nuclear Information System (INIS)

    Sohn, Jung Inn; Nam, Chunghee; Lee, Seonghoon

    2002-01-01

    We have grown vertically aligned carbon nanotubes on the various substrates such as a planar p-type Si(1 0 0) wafer, porous Si wafer, SiO 2 , Si 3 N 4 , Al 2 O 3 , and Cr by thermal chemical vapor deposition (CVD) at 800 deg.C, using C 2 H 2 gas as a carbon source and Fe catalyst films deposited by a pulsed laser on the substrates. The Fe films were deposited for 5 min by pulsed laser deposition (PLD). The advantage of Fe deposition by PLD over other deposition methods lies in the superior adhesion of Fe to a Si substrate due to high kinetic energies of the generated Fe species. Scanning electron microscopy (SEM) images show that vertically well-aligned carbon nanotubes are grown on Fe nanoparticles formed from the thermal annealing of the Fe film deposited by PLD on the various substrates. Atomic force microscopy (AFM) images show that the Fe film annealed at 800 deg.C is broken to Fe nanoparticles of 10-50 nm in size. We show that the appropriate density of Fe nanoparticles formed from the thermal annealing of the film deposited by PLD is crucial in growing vertically aligned carbon nanotubes. Using a PLD and a lift-off method, we developed the selective growth of carbon nanotubes on a patterned Fe-coated Si substrate

  17. Chemical composition of mate tea leaves (Ilex paraguariensis): a study of extraction methods.

    Science.gov (United States)

    Assis Jacques, Rosângela; dos Santos Freitas, Lisiane; Flores Peres, Valéria; Dariva, Cláudio; de Oliveira, José Vladimir; Bastos Caramão, Elina

    2006-12-01

    The objective of this work was to investigate the extraction of Ilex paraguariensis leaves by means of three extraction techniques: pressurized liquid extraction (PLE, also called accelerated solvent extraction--ASE), maceration, and sonication. Samples of mate tea leaves were collected from an experiment conducted under agronomic control at Indfistria e Comércio de Erva-Mate Barão LTDA, Brazil. Six solvents with increasing polarities (n-hexane, toluene, dichloromethane, ethyl acetate, acetone, and methanol) were used in this investigation. Chemical analysis of the extracts was performed by GC coupled with a mass spectrometer detector. The identification and quantification were accomplished by coinjections of certified standards. The results showed that no significant differences in the qualities of the extracts were noticed regarding the extraction methods. On the other hand, the PLE technique was found to be more effective for the extractions of caffeine, phytol, palmitic, and stearic acid. The use of PLE led to a significant decrease in the total extraction time, amount of solvent consumption, and manipulation of samples compared to maceration and ultrasound-assisted extraction methods.

  18. Chemical vapour deposition - a promising method for production of different kinds of carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Leonhardt, A.; Ritschel, M.; Bartsch, K.; Graff, A.; Taeschner, C.; Fink, J. [Institut fuer Festkoerper- und Werkstofforschung Dresden e.V. (Germany)

    2001-08-01

    Carbon nanostructures (fibres, multi and single walled tubes) have been synthesized by catalytic chemical vapour deposition. The catalyst material, deposition temperature and the used hydrocarbon are the main parameters responsible for the formation of the desired structure. In dependence on these parameters and by optimising the deposition process nanofibres with herringbone structure and tubular multiwalled nanotubes were deposited in large amounts and high purity. In the case of single wall nanotubes synthesis an aftertreatment and process is absolutely necessary to obtain material with high percentage of tubes. Layers of disordered and aligned multiwalled nanotubes were deposited on oxidised silicon substrates coated with thin sputtered metal layers (Co, permalloy) by using the micro-wave assisted plasma CVD process or the bias supported hot filament CVD method. The latter method allows relatively low deposition temperatures (550 - 750 C). The obtained carbon modifications were characterised by scanning and transmission electron microscopy. Furthermore, the electron field emission of the CNT's layers were investigated. (orig.)

  19. Comparison of different methods for extraction from Tetraclinis articulata: yield, chemical composition and antioxidant activity.

    Science.gov (United States)

    Herzi, Nejia; Bouajila, Jalloul; Camy, Séverine; Romdhane, Mehrez; Condoret, Jean-Stéphane

    2013-12-15

    In the present study, three techniques of extraction: hydrodistillation (HD), solvent extraction (conventional 'Soxhlet' technique) and an innovative technique, i.e., the supercritical fluid extraction (SFE), were applied to ground Tetraclinis articulata leaves and compared for extraction duration, extraction yield, and chemical composition of the extracts as well as their antioxidant activities. The extracts were analyzed by GC-FID and GC-MS. The antioxidant activity was measured using two methods: ABTS(•+) and DPPH(•). The yield obtained using HD, SFE, hexane and ethanol Soxhlet extractions were found to be 0.6, 1.6, 40.4 and 21.2-27.4 g/kg respectively. An original result of this study is that the best antioxidant activity was obtained with an SFE extract (41 mg/L). The SFE method offers some noteworthy advantages over traditional alternatives, such as shorter extraction times, low environmental impact, and a clean, non-thermally-degraded final product. Also, a good correlation between the phenolic contents and the antioxidant activity was observed with extracts obtained by SFE at 9 MPa. Copyright © 2013 Elsevier Ltd. All rights reserved.

  20. An automated method to find transition states using chemical dynamics simulations.

    Science.gov (United States)

    Martínez-Núñez, Emilio

    2015-02-05

    A procedure to automatically find the transition states (TSs) of a molecular system (MS) is proposed. It has two components: high-energy chemical dynamics simulations (CDS), and an algorithm that analyzes the geometries along the trajectories to find reactive pathways. Two levels of electronic structure calculations are involved: a low level (LL) is used to integrate the trajectories and also to optimize the TSs, and a higher level (HL) is used to reoptimize the structures. The method has been tested in three MSs: formaldehyde, formic acid (FA), and vinyl cyanide (VC), using MOPAC2012 and Gaussian09 to run the LL and HL calculations, respectively. Both the efficacy and efficiency of the method are very good, with around 15 TS structures optimized every 10 trajectories, which gives a total of 7, 12, and 83 TSs for formaldehyde, FA, and VC, respectively. The use of CDS makes it a powerful tool to unveil possible nonstatistical behavior of the system under study. © 2014 Wiley Periodicals, Inc.