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Sample records for electron temperature ionic

  1. Many-electron electrochemical processes. Reactions in molten salts, room-temperature ionic liquids and ionic solutions

    Energy Technology Data Exchange (ETDEWEB)

    Andriiko, Aleksandr A. [National Technical Univ. Ukraine, Kyiv (Ukraine). Kyiv Polytechnic Inst.; Andriyko, Yuriy O. [CEST Centre of Electrochemical Surface Technology, Wiener Neustadt (Austria); Nauer, Gerhard E. [Vienna Univ. (Austria). Inst. of Physical Chemistry

    2013-02-01

    The authors provide a unified concept for understanding multi-electron processes in electrochemical systems such as molten salts, ionic liquids, or ionic solutions. A major advantage of this concept is its independence of assumptions like one-step many-electron transfers or 'discrete' discharge of complex species. This book contains the following main topics: 1. Many-electron electrochemical systems: Concepts and definitions. 2. Many-electron systems at equilibrium. 3. Phenomenology of electrochemical kinetics. 4. Electrode film systems: experimental evidences. 5. Dynamics of a non-equilibrium electrochemical system. 6. Electrochemistry of Ti(IV) in ionic liquids.

  2. Variation of kinetic energy release with temperature and electron energy for unimolecular ionic transitions

    International Nuclear Information System (INIS)

    Rabia, M.A.; Fahmy, M.A.

    1992-01-01

    The kinetic energy released during seven unimolecular ionic transitions, generated from benzyl alcohol and benzyl amine have been studied as a function of ion source temperature and ionizing electron energy. Only, the kinetic energy released during H CN elimination from fragment [C 7 H 8 N]+ ion of benzyl amine displays a temperature dependence. For only two transitions, generated from benzyl alcohol, the kinetic energy released show a significant ionizing electron energy dependence. These results may reveal the role of the internal energy of reacting ions in producing the kinetic energy released some transitions produced from benzyl alcohol

  3. Electronic and ionic conductivities and point defects in ytterbium sesquioxide at high temperature

    International Nuclear Information System (INIS)

    Carpentier, J.-L.; Lebrun, A.; Perdu, F.; Tellier, P.

    1982-01-01

    From the study of complex impedance diagrams applied to a symmetric cell Pt-Yb 2 O 3 -Pt, the authors have shown the mixed character of electrical conduction within the ytterbium sesquioxide. The measurements were performed at thermodynamic equilibrium in the temperature range from 1423 to 1623 K and the partial pressure of oxygen range from 10 -12 to 1 atm. The variations of ionic and electronic conductivity as a function of Psub(O 2 ) were interpreted in terms of four different point defects in the general case of a Frenkel disorder. The relative contributions and the activation energies of conduction of these different defects were determined. (author)

  4. Metal electrodeposition and electron transfer studies of uranium compounds in room temperature ionic liquids

    International Nuclear Information System (INIS)

    Stoll, M.E.; Oldham, W.J.; Costa, D.A.

    2004-01-01

    Room temperature ionic liquids (RTIL's) comprised of 1,3-dialkylimidazolium or quaternary ammonium cations and one of several anions such as PF 6 - , BF 4 - , or - N(SO 2 CF 3 ) 2 , represent a class of solvents that possess great potential for use in applications employing electrochemical procedures. Part of the intrigue with RTIL's stems from some of their inherent solvent properties including negligible vapor pressure, good conductivity, high chemical and thermal stability, and non-flammability. Additionally, a substantial number of RTIL's can be envisioned simply by combining different cation and anion pairs, thereby making them attractive for specific application needs. We are interested in learning more about the possible use of RTIL's within the nuclear industry. In this regard our research team has been exploring the electron transfer behavior of simple metal ions in addition to coordination and organometallic complexes in these novel solvents. Results from our research have also provided us with insight into the bonding interactions between our current anion of choice, bis(trifluoromethylsulfonyl)imide = NTf 2 , and open coordination sites on actinide and transition metal fragments. This presentation will focus on recent results in two areas: the electrodeposition of electropositive metal ions from RTIL solutions and the electron transfer behavior for several uranium complexes. Details concerning the cathodic electrodeposition and anodic stripping of alkali metals (Na, K) from various working electrode surfaces (Pt, Au, W, Glassy Carbon) will be discussed. Figure 1 displays typical behavior for the electrodeposition of potassium metal from an RTIL containing potassium ions produced through the reaction of KH with H[NTf 2 ]. Our efforts with other metal ions, including our results to date with uranium electrodeposition, will be covered during the presentation. The electron transfer behavior for a number of uranium complexes have been studied with various

  5. Polarization versus Temperature in Pyridinium Ionic Liquids

    DEFF Research Database (Denmark)

    Chaban, V. V.; Prezhdo, O. V.

    2014-01-01

    Electronic polarization and charge transfer effects play a crucial role in thermodynamic, structural, and transport properties of room-temperature ionic liquids (RTILs). These nonadditive interactions constitute a useful tool for tuning physical chemical behavior of RTILs. Polarization and charge...... interactions changes negligibly between 300 and 900 K, while the average dipole moment increases due to thermal fluctuations of geometries. Our results contribute to the fundamental understanding of electronic effects in the condensed phase of ionic systems and foster progress in physical chemistry...

  6. IMPROVED SYNTHESIS OF ROOM TEMPERATURE IONIC LIQUIDS

    Science.gov (United States)

    Room temperature ionic liquids (RTILs), molten salts comprised of N-alkylimidazolium cations and various anions, have received significant attention due to their commercial potential in a variety of chemical applications especially as substitutes for conventional volatile organic...

  7. Ionic and electronic conductivity in lead-zirconate-titanate (PZT)

    NARCIS (Netherlands)

    Boukamp, Bernard A.; Pham thi ngoc mai, P.T.N.M.; Blank, David H.A.; Bouwmeester, Henricus J.M.

    2004-01-01

    Accurate impedance measurements on differently sized samples of lead–zirconate–titanate (PbZr0.53Ti0.47O3, PZT) have been analyzed with a CNLS procedure, resulting in the separation of the ionic and electronic conductivities over a temperature range from f150 to 630 jC. At 603 jC the electronic

  8. Direct electron transfer of hemoglobin immobilized in a mesocellular siliceous foams supported room temperature ionic liquid matrix and the electrocatalytic reduction of H2O2

    International Nuclear Information System (INIS)

    Yu Jingjing; Zhao Tian; Zhao Faqiong; Zeng Baizhao

    2008-01-01

    Room temperature ionic liquid (RTIL) 1-butyl-3-methylimidazolium hexafluorophosphate (BMIM.PF 6 ) has been successfully immobilized on mesocellular siliceous foams (MSFs) by using a specific annealing method. Nitrogen adsorption/desorption isotherms and scanning electron microscopy (SEM) images reveal that most pores of MSFs are filled with the RTIL and the outer surfaces of MSFs are covered with the RTIL. When hemoglobin (Hb) is immobilized with the resulting hybrid material on a glassy carbon electrode (GCE), a pair of well-defined and quasi-reversible voltammetric peaks for Hb Fe(III)/Fe(II) is obtained. Its formal potential is -0.330 V (vs. saturated calomel electrode) in pH 7.0 phosphate buffer solution (PBS). The peak currents are much larger than those of Hb immobilized with MSFs or BMIM.PF 6 -MSFs mixture. This indicates that the hybrid material has stronger promotion to the direct electron transfer of Hb, which is related to the effective immobilization of BMIM.PF 6 on MSFs. The electron-transfer rate constant (k s ) is estimated to be 1.91 s -1 . The immobilized Hb retains its native conformation and shows high electrocatalysis to the reduction of H 2 O 2 . Under the optimized experimental conditions, the catalytic current is linear to the concentration of H 2 O 2 from 0.2 to 28 μM, and the detection limit is 8 x 10 -8 M (S/N = 3). The linear range is wider than those for Hb immobilized with MSFs or BMIM.PF 6 -MSFs mixture. Thus, the MSFs supported RTILs hybrid material is an ideal matrix for protein immobilization and biosensor fabrication

  9. Combination of the ionic-to-atomic line intensity ratios from two test elements for the diagnostic of plasma temperature and electron number density in Inductively Coupled Plasma Atomic Emission Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Tognoni, E. [Istituto per i Processi Chimico-Fisici, Area della Ricerca del Consiglio Nazionale delle Ricerche Via Moruzzi 1, 56124 Pisa (Italy)], E-mail: tognoni@ipcf.cnr.it; Hidalgo, M.; Canals, A. [Departamento de Quimica Analitica, Nutricion y Bromatologia. Universidad de Alicante. Apdo. 99, 03080, Alicante (Spain); Cristoforetti, G.; Legnaioli, S.; Salvetti, A.; Palleschi, V. [Istituto per i Processi Chimico-Fisici, Area della Ricerca del Consiglio Nazionale delle Ricerche Via Moruzzi 1, 56124 Pisa (Italy)

    2007-05-15

    In Inductively Coupled Plasma-Atomic Emission Spectroscopy (ICP-AES) spectrochemical analysis, the MgII(280.270 nm)/MgI(285.213 nm) ionic to atomic line intensity ratio is commonly used as a monitor of the robustness of operating conditions. This approach is based on the univocal relationship existing between intensity ratio and plasma temperature, for a pure argon atmospheric ICP in thermodynamic equilibrium. In a multi-elemental plasma in the lower temperature range, the measurement of the intensity ratio may not be sufficient to characterize temperature and electron density. In such a range, the correct relationship between intensity ratio and plasma temperature can be calculated only when the complete plasma composition is known. We propose the combination of the line intensity ratios of two test elements (double ratio) as an effective diagnostic tool for a multi-elemental low temperature LTE plasma of unknown composition. In particular, the variation of the double ratio allows us discriminating changes in the plasma temperature from changes in the electron density. Thus, the effects on plasma excitation and ionization possibly caused by introduction of different samples and matrices in non-robust conditions can be more accurately interpreted. The method is illustrated by the measurement of plasma temperature and electron density in a specific analytic case.

  10. Pulse radiolysis study on solvated electrons in ionic liquid with controlling water content

    International Nuclear Information System (INIS)

    Yang Jinfeng; Kondoh, T.; Yoshida, Y.; Nagaishi, R.

    2006-01-01

    Room-temperature ionic liquids, which are nonvolatile and nonflammable, have been proposed as 'green solvents' for new applications in chemical synthesis, separation chemistry, electrochemistry and other areas. In the separation chemistry, the hydrophobic ionic liquids have been practically expected to be alternative to traditional organic solvents for solvent extraction of 4f and 5f elements from the viewpoints of the immiscibility in water, especially in the spent nuclear fuel reprocessing. However, the chemical reaction or kinetics studies are important to apply the ionic liquids for various processes. To understand the effects of ionic liquids on chemical reactions, pulse radiolysis studies of ionic liquid have been carried out on nanosecond scale by using a 27 MeV electron beam and an analyzing light source of xenon lamp. In the experiment, a hydrophobic ionic liquid of diethylmethyl(2-methoxy)ammonium-bis(trifluoromethanesulfonyl)imide (DEMMA-TFSI) salt was used. The ionic liquid of DEMMA-TFSI was prepared by reacting equimolar amounts of diethylmethyl(2-methoxy)ammonium chloride (C 10 H 20 F 6 N 2 O 5 S 2 Cl, >98%, Nisshinbo) with lithium bis(trifluoromethanesulfonyl)imide (LiN(SO 2 CF 3 ) 2 , SynQuest Labs., Inc.) in aqueous solutions at room temperature. The ionic liquid was separated from the aqueous phase, purified by repeated extractions with water to LiCl and excess reagent, and finally dried at 110 degree C under vacuum. The transient absorptions of the ionic liquid were measured at wavelengths from 350 to 1400 nm, in which two photodiodes of silicon ( 1000 nm) were used. The spectrum of solvated electrons in the ionic liquid of DEMMA-TFSI was obtained with an absorption peak of 1060 nm and a wide bandwidth of about 600 nm (FWHM). The decay constant of the solvated electrons in the ionic liquid was 1.54 x 10 7 s -1 , which is independent on the wavelength. The absorption peak of the spectrum was blue-shifted from 1060 to 780 nm with increasing water

  11. Water in Room Temperature Ionic Liquids

    Science.gov (United States)

    Fayer, Michael

    2014-03-01

    Room temperature ionic liquids (or RTILs, salts with a melting point below 25 °C) have become a subject of intense study over the last several decades. Currently, RTIL application research includes synthesis, batteries, solar cells, crystallization, drug delivery, and optics. RTILs are often composed of an inorganic anion paired with an asymmetric organic cation which contains one or more pendant alkyl chains. The asymmetry of the cation frustrates crystallization, causing the salt's melting point to drop significantly. In general, RTILs are very hygroscopic, and therefore, it is of interest to examine the influence of water on RTIL structure and dynamics. In addition, in contrast to normal aqueous salt solutions, which crystallize at low water concentration, in an RTIL it is possible to examine isolated water molecules interacting with ions but not with other water molecules. Here, optical heterodyne-detected optical Kerr effect (OHD-OKE) measurements of orientational relaxation on a series of 1-alkyl-3-methylimidazolium tetrafluoroborate RTILs as a function of chain length and water concentration are presented. The addition of water to the longer alkyl chain RTILs causes the emergence of a long time bi-exponential orientational anisotropy decay. Such decays have not been seen previously in OHD-OKE experiments on any type of liquid and are analyzed here using a wobbling-in-a-cone model. The orientational relaxation is not hydrodynamic, with the slowest relaxation component becoming slower as the viscosity decreases for the longest chain, highest water content samples. The dynamics of isolated D2O molecules in 1-butyl-3-methylimidazolium hexafluorophosphate (BmImPF6) were examined using two dimensional infrared (2D IR) vibrational echo spectroscopy. Spectral diffusion and incoherent and coherent transfer of excitation between the symmetric and antisymmetric modes are examined. The coherent transfer experiments are used to address the nature of inhomogeneous

  12. Electron-ionic technology of storage of foodstuffs

    International Nuclear Information System (INIS)

    Tsoj, A.P.

    1996-01-01

    Work is trained on reduction of food suffer losses under cold store due to its drying and spoiling. Experimental cold store of fruits in 'microclimates' in electron-ionic medium created with help of pilot unit is carried out

  13. Enhanced Mixed Electronic-Ionic Conductors through Cation Ordering

    Energy Technology Data Exchange (ETDEWEB)

    Jacobson, Allan J. [Univ. of Houston, TX (United States); Morgan, Dane [Univ. of Wisconsin, Madison, WI (United States); Grey, Clare [Stony Brook Univ., NY (United States)

    2014-08-31

    The performance of many energy conversion and storage devices depend on the properties of mixed ionic-electronic conducting (miec) materials. Mixed or ambipolar conductors simultaneously transport ions and electrons and provide the critical interface between chemical and electrical energy in devices such as fuel cells, ion transport membranes, and batteries. Enhancements in storage capacity, reversibility, power density and device lifetime all require new materials and a better understanding of the fundamentals of ambipolar conductivity and surface reactivity.The high temperature properties of the ordered perovksites AA’B2O5+x, where A = rare earth ion, Y and B = Ba, Sr were studied. The work was motivated by the high oxygen transport and surface exchange rates observed for members of this class of mixed ionic and electronic conductors. A combined experimental and computational approach, including structural, electrochemical, and transport characterization and modeling was used. The approach attacks the problem simultaneously at global (e.g., neutron diffraction and impedance spectroscopy), local (e.g., pair distribution function, nuclear magnetic resonance) and molecular (ab initio thermokinetic modeling) length scales. The objectives of the work were to understand how the cation and associated anion order lead to exceptional ionic and electronic transport properties and surface reactivity in AA’B2O5+x perovskites. A variety of compounds were studied by X-ray and neutron diffraction, measurements of thermodynamics and transport and theoretically. These included PrBaCo2O5+x and NdBaCo2O5+x, PrBaCo2-xFexO6- δ (x = 0, 0.5, 1.0, 1.5 and 2) and LnBaCoFeO6- δ (Ln = La, Pr, Nd, Sm, Eu and Gd), Sr3YCo4O10.5, YBaMn2O5+x. A0.5A’0.5BO3 (where A=Y, Sc, La, Ce, Pr, Nd, Pm, Sm; A’= Sr

  14. Improvement of SOFC electrodes using mixed ionic-electronic conductors

    Energy Technology Data Exchange (ETDEWEB)

    Matsuzaki, Y.; Hishinuma, M. [Tokyo Gas Co., Ltd. (Japan)

    1996-12-31

    Since the electrode reaction of SOFC is limited to the proximity of a triple phase boundary (TPB), the local current density at the electrode and electrolyte interface is larger than mean current density, which causes large ohmic and electrode polarization. This paper describes an application of mixed ionic-electronic conductors to reduce such polarization by means of (1) enhancing ionic conductivity of the electrolyte surface layer by coating a high ionic conductors, and (2) reducing the local current density by increasing the electrochemically active sites.

  15. Contribution to the characterization of room temperature ionic liquids under ionizing irradiation

    International Nuclear Information System (INIS)

    Le Rouzo, G.; Lamouroux, Ch.; Moutiers, G.

    2010-01-01

    Room-Temperature Ionic Liquids are potentially interesting for nuclear fuel treatment. Within this framework, ionic liquids stability towards ionizing radiations (α, β or γ) is determining their potential application. The aim of this work is to assess a better understanding of ionic liquids behaviour under radiolysis. Ionic liquids chosen in these studies are constituted with BuMeIm + (or Bu 3 MeN + ) cation associated with various anions: Tf 2 N - , TfO - , PF 6 - and BF 4 - . Moreover, development of suitable chemical analysis tools crucial for characterization of these compounds has been realized. Ionic liquids stability has been mainly studied under γ irradiation, but also under electron beam or heavy particles irradiations. Ionic liquids degradation under radiolysis has been determined with two complementary approaches. The first one aims at understanding radio-induced degradation mechanisms with radical species analysis by Electron Paramagnetic Resonance spectroscopy (EPR). The second one aims at characterizing stable radiolysis products formed in liquid and gaseous phases. Studies were conducted with several analytical techniques: Electro Spray Ionisation Mass Spectrometry (ESI-MS), High Pressure Liquid Chromatography (HPLC, HPLC/UV-VIS, HPLC/ESI-MS), Gas Analysis Mass Spectrometry (Gas MS) and Gas Chromatography hyphenated with Mass Spectrometry (GC/MS). Firstly, the ionic liquid [Bu 3 MeIm][Tf 2 N] has been studied under γ irradiation. Radiolytic stability has been quantitatively assessed for high doses of radiations and a proposal of degradation scheme has been proposed on the basis of radio-induced radicals and radiolysis products analysis. Those data have been compared to those obtained for the γ radiolysis of the ionic liquid [Bu 3 MeN][Tf 2 N], enabling to assess cation influence on ionic liquids radiolysis. Secondly, degradation under γ irradiation of ionic liquids [BuMeIm][X] (X - Tf 2 N - , TfO - , PF 6 - , BF 4 - ) has been quantitatively

  16. Room temperature electrodeposition of actinides from ionic solutions

    Science.gov (United States)

    Hatchett, David W.; Czerwinski, Kenneth R.; Droessler, Janelle; Kinyanjui, John

    2017-04-25

    Uranic and transuranic metals and metal oxides are first dissolved in ozone compositions. The resulting solution in ozone can be further dissolved in ionic liquids to form a second solution. The metals in the second solution are then electrochemically deposited from the second solutions as room temperature ionic liquid (RTIL), tri-methyl-n-butyl ammonium n-bis(trifluoromethansulfonylimide) [Me.sub.3N.sup.nBu][TFSI] providing an alternative non-aqueous system for the extraction and reclamation of actinides from reprocessed fuel materials. Deposition of U metal is achieved using TFSI complexes of U(III) and U(IV) containing the anion common to the RTIL. TFSI complexes of uranium were produced to ensure solubility of the species in the ionic liquid. The methods provide a first measure of the thermodynamic properties of U metal deposition using Uranium complexes with different oxidation states from RTIL solution at room temperature.

  17. Highly Confined Electronic and Ionic Conduction in Oxide Heterostructures

    DEFF Research Database (Denmark)

    Pryds, Nini

    2015-01-01

    The conductance confined at the interface of complex oxide heterostructures provides new opportunities to explore nanoelectronic as well as nanoionic devices. In this talk I will present our recent results both on ionic and electronic conductivity at different heterostructures systems. In the first...... unattainable for Bi2O3-based materials, is achieved[1]. These confined heterostructures provide a playground not only for new high ionic conductivity phenomena that are sufficiently stable but also uncover a large variety of possible technological perspectives. At the second part, I will discuss and show our...

  18. Ionic molecular films. Applications. 3. Electron beam stimulated enhanced adherence

    Energy Technology Data Exchange (ETDEWEB)

    Baldacchini, G; Montereali, R M; Scavarda do Carmo, L C

    1989-11-01

    This paper reports on the advantages of the use of the technique of electron beam lithography to imprint enhanced sensitive patterns on ionic molecular substrates (bulk crystals or films). With this technique, localized superficial defects are produced which change the chemical properties of surfaces. Sensitized surfaces react with absorbates providing enhanced adherence of such substances. The use of spacially controlled electron beams allows the construction of small (sub-micron) feature chemical and very localized enhanced adherence of absorbates.

  19. Thermoelectric power in ionic and electronic mixed conductors

    Energy Technology Data Exchange (ETDEWEB)

    Kamata, Masahiro; Jin-nouchi, Kenji; Esaka, Takao [Tottori Univ. (Japan). Faculty of Engineering

    1996-08-01

    In order to study the thermoelectric property of the oxide ionic and electronic mixed conductor of 10 mol% CaO-doped CeO{sub 2} (CDC), a new type of thermocell was prepared, in which platinum electrodes were embedded in the tube-type sample to diminish the large temperature gradient over the electrodes due to the local heat radiation from heating furnace. Using this thermocell, reproducible data were obtained. The thermoelectric power measured in CDC under various oxygen atmospheres (Po{sub 2}) from 1.0 to about 10{sup -15} atm showed that the sign of Seebeck coefficients changed from minus to plus. This variation of Seebeck coefficients vs. Po{sub 2} was well interpreted by considering that (1) the thermoelectric power could be a driving force to make actual and electrochemical oxygen transfer in the mixed conductor and (2) the electrode processes had limiting rates due to slow oxygen diffusion (or oxygen gas exhaustion at the cathode and evolution at the anode). (author)

  20. Ionic Conductivity of the Perovskites, NaMgF3MgF3 and KZnF3 at High Temperatures

    DEFF Research Database (Denmark)

    Andersen, N. H.; Kjems, Jørgen; Hayes, W.

    1985-01-01

    We have carried out a study of the ionic conductivity of NaMgF3, KMgF3 and KZnF3 up to temperatures close to the melting point. Our results, in contrast to previous reports in the literature, show no abnormal ionic conductivity at high temperatures. Care in interpretation of results is required...... because of surface electronic conduction....

  1. Low Temperature Reduction of Alumina Using Fluorine Containing Ionic Liquids

    Energy Technology Data Exchange (ETDEWEB)

    Dr. R. G. Reddy

    2007-09-01

    The major objective of the project is to establish the feasibility of using specific ionic liquids capable of sustaining aluminum electrolysis near room temperature at laboratory and batch recirculation scales. It will explore new technologies for aluminum and other valuable metal extraction and process methods. The new technology will overcome many of the limitations associated with high temperatures processes such as high energy consumption and corrosion attack. Furthermore, ionic liquids are non-toxic and could be recycled after purification, thus minimizing extraction reagent losses and environmental pollutant emissions. Ionic liquids are mixture of inorganic and organic salts which are liquid at room temperature and have wide operational temperature range. During the last several years, they were emerging as novel electrolytes for extracting and refining of aluminum metals and/or alloys, which are otherwise impossible using aqueous media. The superior high temperature characteristics and high solvating capabilities of ionic liquids provide a unique solution to high temperature organic solvent problems associated with device internal pressure build-up, corrosion, and thermal stability. However their applications have not yet been fully implemented due to the insufficient understanding of the electrochemical mechanisms involved in processing of aluminum with ionic liquids. Laboratory aluminum electrodeposition in ionic liquids has been investigated in chloride and bis (trifluoromethylsulfonyl) imide based ionic liquids. The electrowinning process yielded current density in the range of 200-500 A/m2, and current efficiency of about 90%. The results indicated that high purity aluminum (>99.99%) can be obtained as cathodic deposits. Cyclic voltammetry and chronoamperometry studies have shown that initial stages of aluminum electrodeposition in ionic liquid electrolyte at 30°C was found to be quasi-reversible, with the charge transfer coefficient (0.40). Nucleation

  2. Trivalent europium speciation in a room-temperature ionic liquid

    International Nuclear Information System (INIS)

    Mekki, S.

    2006-10-01

    Since the nuclear industry is playing an important role in the power production field, a relevant number of problems have been revealed. Indeed, high-level radioactive long-lived nuclear wastes present a real difficulty for nuclear wastes management. Minor actinides, which compose most of these wastes, will be radioactive for several thousands of years. For eventual disposal deep underground, their reprocessing needs to be optimized. The extraction processes used industrially to separate actinides and lanthanides from other metal species characterizing the spent nuclear fuel produce, nevertheless, enormous quantities of contaminated liquid wastes directly issued from the liquid/liquid extraction step. During the last decade, some room-temperature ionic liquid have been studied and integrated into industrial processes. The interest on this class of solvent came out from their 'green' properties (non volatile, non flammable, recyclable, etc...), but also from the variability of their physico-chemical properties (stability, hydrophobicity, viscosity) as a function of the RTIL chemical composition. Indeed, it has been shown that classical chemical industrial processes could be transferred into those media, even more improved, while a certain number of difficulties arising from using traditional solvent can be avoided. In this respect, it could be promising to investigate the ability to use room-temperature ionic liquid into the spent nuclear fuel reprocessing field. The aim of this thesis is to test the ability of the specific ionic liquid bumimTf 2 N to allow trivalent europium extraction. The choice of this metal is based on the chemical analogy with trivalent minor actinides Curium and Americium which are contributing the greatest part of the long-lived high-level radioactive wastes. Handling these elements needs to be very cautious for the safety and radioprotection aspect. Moreover, europium is a very sensitive luminescent probe to its environment even at the

  3. Full characterization of polypyrrole thin films electrosynthesized in room temperature ionic liquids, water or acetonitrile

    International Nuclear Information System (INIS)

    Viau, L.; Hihn, J.Y.; Lakard, S.; Moutarlier, V.; Flaud, V.; Lakard, B.

    2014-01-01

    Highlights: • Polypyrrole films were electrodeposited from three room temperature ionic liquids. • Polymer films were characterized using many surface analysis techniques. • The incorporation of anions and/or cations inside the polymer films was evidenced. • The influence of the ionic liquid on the polymer properties was deeply studied. - Abstract: Pyrrole was electrochemically oxidized in two conventional media (water and acetonitrile) and in three room temperature ionic liquids: 1-butyl-3-methylimidazolium hexafluorophosphate, 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide, and 1-butyl-1-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide. Infrared and Raman Spectroscopies confirmed the formation of polypyrrole by electropolymerization but were unable to demonstrate the presence of anions in the polymer films. The use of ionic liquids as growth media resulted in polymer films having a good electrochemical activity. The difference of activity from one polymer film to the other was mainly attributed to the difference of viscosity between the solvents used. The morphological features of the polypyrrole films were also fully studied. Profilometric measurements demonstrated that polymer films grown, at the same potential, in ionic liquids were thinner and had a smaller roughness than those grown in other solvents. Atomic Force Microscopy showed that polypyrrole films had nearly similar micrometric nodular structure whatever the growth medium even if some differences of porosity and homogeneity were observed using Scanning Electron Microscopy. The incorporation of counter-anions at the top surface of the films was finally evidenced by X-ray Photoelectron Spectroscopy. These anions were also incorporated inside the polymer film with a uniform distribution as shown by Glow Discharge Optical Emission Spectroscopy

  4. Average-atom model for two-temperature states and ionic transport properties of aluminum in the warm dense matter regime

    Science.gov (United States)

    Hou, Yong; Fu, Yongsheng; Bredow, Richard; Kang, Dongdong; Redmer, Ronald; Yuan, Jianmin

    2017-03-01

    The average-atom model combined with the hyper-netted chain approximation is an efficient tool for electronic and ionic structure calculations for warm dense matter. Here we generalize this method in order to describe non-equilibrium states with different electron and ion temperature as produced in laser-matter interactions on ultra-short time scales. In particular, the electron-ion and ion-ion correlation effects are considered when calculating the electron structure. We derive an effective ion-ion pair-potential using the electron densities in the framework of temperature-depended density functional theory. Using this ion-ion potential we perform molecular dynamics simulations in order to determine the ionic transport properties such as the ionic diffusion coefficient and the shear viscosity through the ionic velocity autocorrelation functions.

  5. Quantum chemical aided prediction of the thermal decomposition mechanisms and temperatures of ionic liquids

    International Nuclear Information System (INIS)

    Kroon, Maaike C.; Buijs, Wim; Peters, Cor J.; Witkamp, Geert-Jan

    2007-01-01

    The long-term thermal stability of ionic liquids is of utmost importance for their industrial application. Although the thermal decomposition temperatures of various ionic liquids have been measured previously, experimental data on the thermal decomposition mechanisms and kinetics are scarce. It is desirable to develop quantitative chemical tools that can predict thermal decomposition mechanisms and temperatures (kinetics) of ionic liquids. In this work ab initio quantum chemical calculations (DFT-B3LYP) have been used to predict thermal decomposition mechanisms, temperatures and the activation energies of the thermal breakdown reactions. These quantum chemical calculations proved to be an excellent method to predict the thermal stability of various ionic liquids

  6. Actinide, lanthanide and fission product speciation and electrochemistry in high and low temperature ionic melts

    Energy Technology Data Exchange (ETDEWEB)

    Bhatt, Anand I.; Kinoshita, Hajime; Koster, Anne L.; May, Iain; Sharrad, Clint A.; Volkovich, Vladimir A.; Fox, O. Danny; Jones, Chris J.; Lewin, Bob G.; Charnock, John M.; Hennig, Christoph

    2004-07-01

    There is currently a great deal of research interest in the development of molten salt technology, both classical high temperature melts and low temperature ionic liquids, for the electrochemical separation of the actinides from spent nuclear fuel. We are interested in gaining a better understanding of actinide and key fission product speciation and electrochemical properties in a range of melts. Our studies in high temperature alkali metal melts (including LiCl and LiCl-KCl and CsCl-NaCl eutectics) have focussed on in-situ species of U, Th, Tc and Ru using X-ray absorption spectroscopy (XAS, both EXAFS and XANES) and electronic absorption spectroscopy (EAS). We report unusual actinide speciation in high temperature melts and an evaluation of the likelihood of Ru or Tc volatilization during plant operation. Our studies in lower temperature melts (ionic liquids) have focussed on salts containing tertiary alkyl group 15 cations and the bis(tri-fluor-methyl)sulfonyl)imide anion, melts which we have shown to have exceptionally wide electrochemical windows. We report Ln, Th, U and Np speciation (XAS, EAS and vibrational spectroscopy) and electrochemistry in these melts and relate the solution studies to crystallographic characterised benchmark species. (authors)

  7. Actinide, lanthanide and fission product speciation and electrochemistry in high and low temperature ionic melts

    International Nuclear Information System (INIS)

    Bhatt, Anand I.; Kinoshita, Hajime; Koster, Anne L.; May, Iain; Sharrad, Clint A.; Volkovich, Vladimir A.; Fox, O. Danny; Jones, Chris J.; Lewin, Bob G.; Charnock, John M.; Hennig, Christoph

    2004-01-01

    There is currently a great deal of research interest in the development of molten salt technology, both classical high temperature melts and low temperature ionic liquids, for the electrochemical separation of the actinides from spent nuclear fuel. We are interested in gaining a better understanding of actinide and key fission product speciation and electrochemical properties in a range of melts. Our studies in high temperature alkali metal melts (including LiCl and LiCl-KCl and CsCl-NaCl eutectics) have focussed on in-situ species of U, Th, Tc and Ru using X-ray absorption spectroscopy (XAS, both EXAFS and XANES) and electronic absorption spectroscopy (EAS). We report unusual actinide speciation in high temperature melts and an evaluation of the likelihood of Ru or Tc volatilization during plant operation. Our studies in lower temperature melts (ionic liquids) have focussed on salts containing tertiary alkyl group 15 cations and the bis(tri-fluor-methyl)sulfonyl)imide anion, melts which we have shown to have exceptionally wide electrochemical windows. We report Ln, Th, U and Np speciation (XAS, EAS and vibrational spectroscopy) and electrochemistry in these melts and relate the solution studies to crystallographic characterised benchmark species. (authors)

  8. Mixed ionic-electronic conductor-based radiation detectors and methods of fabrication

    Science.gov (United States)

    Conway, Adam; Beck, Patrick R; Graff, Robert T; Nelson, Art; Nikolic, Rebecca J; Payne, Stephen A; Voss, Lars; Kim, Hadong

    2015-04-07

    A method of fabricating a mixed ionic-electronic conductor (e.g. TlBr)-based radiation detector having halide-treated surfaces and associated methods of fabrication, which controls polarization of the mixed ionic-electronic MIEC material to improve stability and operational lifetime.

  9. Electronic and Ionic Conductors from Ordered Microporous Materials

    Energy Technology Data Exchange (ETDEWEB)

    Dincă, Mircea [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)

    2017-10-30

    The proposed work aimed to establish metal-organic frameworks (MOFs) as new classes of high-surface area microporous electronic and ionic conductors. MOFs are crystalline materials with pore sizes ranging from 0.2 to ~ 2 nm (or larger for the latter) defined by inorganic or organic building blocks connected by rigid organic linkers. Myriad applications have been found or proposed for these materials, yet those that require electron transport or conductivity in combination with permanent porosity still lag behind because the vast majority of known frameworks are electrical insulators. Prior to our proposal and subsequent work, there were virtually no studies exploring the possibility of electronic delocalization in these materials. Therefore, our primary goal was to understand and control, at a fundamental level, the electron and ion transport properties of this class of materials, with no specific application proposed, although myriad applications could be envisioned for high surface area conductors. Our goals directly addressed one of the DOE-identified Grand Challenges for Basic Energy Sciences: designing perfect atom- and energy-efficient syntheses of revolutionary new forms of matter with tailored properties. Indeed, the proposed work is entirely synthetic in nature; owing to the molecular nature of the building blocks in MOFs, there is the possibility of unprecedented control over the structure and properties of solid crystalline matter. The goals also tangentially addressed the Grand Challenge of controlling materials processes at the level of electrons: the scope of our program is to create new materials where charges (electrons and/or ions) move according to predefined pathways.

  10. Heat Capacity of Room-Temperature Ionic Liquids: A Critical Review

    Science.gov (United States)

    Paulechka, Yauheni U.

    2010-09-01

    Experimental data on heat capacity of room-temperature ionic liquids in the liquid state were compiled and critically evaluated. The compilation contains data for 102 aprotic ionic liquids from 63 literature references and covers the period of time from 1998 through the end of February 2010. Parameters of correlating equations for temperature dependence of the heat capacities were developed.

  11. Improvement in Dissolution of Cotton Pulp with Ionic liquid by the Electron Beam Treatment

    International Nuclear Information System (INIS)

    Lee, Won Sil; Jung, Wong Gi; Sung, Yong Joo

    2013-01-01

    Electron beam treatment was applied for improving dissolution of cotton pulp with ionic liquids. Two ionic liquids, 1-allyl-3-methylimidazolium chloride ([Amim]Cl]: AC) and 1,3-dimethylimidzolium methlphosphite ([Dmim][(MeO)(H)PO2]: Me) were used for this experiment. Treatment with electron beams up to dose of 400 kGy resulted in the increase of hot water extract and alkali extract of cotton pulp and the great reduction in the molecular weight of cellulose. For the dissolution of cotton pulp with two ionic liquids, the electron beam treated samples showed faster dissolution. The dissolved cellulose with Me ionic liquid were regenerated with Acetonitrile and the structure of regenerated cellulose showed distinct difference depending on the electron beam treatment. Those results provide the electron beam pre-treatment could be applied as an energy efficient and environmentally benign method to increase the dissolution of cotton pulp with ionic liquids

  12. Ionic current devices-Recent progress in the merging of electronic, microfluidic, and biomimetic structures.

    Science.gov (United States)

    Koo, Hyung-Jun; Velev, Orlin D

    2013-05-09

    We review the recent progress in the emerging area of devices and circuits operating on the basis of ionic currents. These devices operate at the intersection of electrochemistry, electronics, and microfluidics, and their potential applications are inspired by essential biological processes such as neural transmission. Ionic current rectification has been demonstrated in diode-like devices containing electrolyte solutions, hydrogel, or hydrated nanofilms. More complex functions have been realized in ionic current based transistors, solar cells, and switching memory devices. Microfluidic channels and networks-an intrinsic component of the ionic devices-could play the role of wires and circuits in conventional electronics.

  13. Mixed ionic-electronic conduction in Ni doped lanthanum gallate perovskites

    Energy Technology Data Exchange (ETDEWEB)

    Long, N.J.; Tuller, H.L.

    1998-07-01

    Lanthanum gallate is a promising material for monolithic fuel cells or oxygen pumps, i.e., one in which the electrolyte and electrodes are formed from a common phase. The authors have investigated La{sub 1{minus}x}Sr{sub x}Ga{sub 1{minus}y}Ni{sub y}O{sub 3} (LSGN{sub x{minus}y}) with x = 0.1 and y = 0.2 and 0.5 as a potential cathode material for such an electrochemical device. The {sigma}(PO{sub 2},T) for LSGN{sub 10--20} points to a p-type electronic conductivity at high PO{sub 2} and predominantly ionic conductivity at low PO{sub 2}. LSGN{sub 10-50} has an electronic conductivity suitable for SOFC applications of approximately 50 S/cm in air at high temperature. AC impedance spectroscopy on an electron blocking cell of the form M/LSG/LSGN/LSG/M was used to isolate the ionic conductivity in the LSGN{sub 10--20} material. The ionic conductivity was found to have a similar magnitude and activation energy to that of undoped LSG material with {sigma}{sub i} = 0.12 S/cm at 800 C and E{sub A} = 1.0 {+-} 0.1 eV. Thermal expansion measurements on the LSGN materials were characterized as a function of temperature and dopant level and were found to match that of the electrolyte under operating conditions.

  14. Temperature tunable micellization of polystyrene-block-poly(2-vinylpyridine) at Si-ionic liquid interface.

    Science.gov (United States)

    Lu, Haiyun; Lee, Dong Hyun; Russell, Thomas P

    2010-11-16

    Highly ordered and stable micelles formed from both symmetric and asymmetric block copolymers of polystyrene-block-poly(2-vinylpyridine) (PS-b-P2VP) at the Si-ionic liquid (IL) interface have been investigated by scanning force microscopy (SFM) and transmission electron microscopy (TEM). The 1-butyl-3-methylimidazolium trifluoromethanesulfonate IL, a selective and temperature-tunable solvent for the P2VP block, was used and gave rise to block copolymer micelles having different morphologies that strongly depended on the annealing temperature. The effects of film thickness, molecular weight of block copolymers, and experimental conditions, such as preannealing, rinsing, and substrate properties, on the morphologies of block copolymer micelles were also studied. In addition, spherical micelles consisting of PS core and P2VP shell could also be obtained by core-corona inversion by annealing the as-coated micellar film in the IL at high temperatures. The possible mechanism for micelle formation is discussed.

  15. Thermochemical stability of zirconia-titanium nitride as mixed ionic-electronic composites

    DEFF Research Database (Denmark)

    Silva, P. S. M.; Esposito, V.; Marani, D.

    2018-01-01

    Dense zirconia (8% molar yttria-stabilized ZrO2)-titanium nitride (TiN) composites are fabricated to obtain mixed ionic-electronic conducting ceramic systems with high degree of electronic and thermal conductivity. The composites are consolidated by spark plasma sintering (SPS), starting from pure...... the composites, high electrical conductivity is attained. Samples exhibit metallic behavior, showing an unexpected percolation of TiN in the YSZ matrix for volume fraction ≤ 25 wt% (27 vol%). Chemical degradation and electrical properties of the compounds were monitored under oxidative (air) and inert (Ar...... transport properties of the composite can be tuned by both the relative volume fraction of phases and controlled oxidative treatments. Adjusting such parameters different electric behaviors were observed ranging from predominant electronic conductors, to temperature-independent resistivity...

  16. Ionic fragmentation channels in electron collisions of small molecular ions

    International Nuclear Information System (INIS)

    Hoffmann, Jens

    2009-01-01

    Dissociative Recombination (DR) is one of the most important loss processes of molecular ions in the interstellar medium (IM). Ion storage rings allow to investigate these processes under realistic conditions. At the Heidelberg test storage ring TSR a new detector system was installed within the present work in order to study the DR sub-process of ion pair formation (IPF). The new detector expands the existing electron target setup by the possibility to measure strongly deflected negative ionic fragments. At the TSR such measurements can be performed with a uniquely high energy resolution by independently merging two electron beams with the ion beam. In this work IPF of HD + , H 3 + and HF + has been studied. In the case of HD + the result of the high resolution experiment shows quantum interferences. Analysis of the quantum oscillations leads to a new understanding of the reaction dynamics. For H 3 + it was for the first time possible to distinguish different IPF channels and to detect quantum interferences in the data. Finally the IPF of HF + was investigated in an energy range, where in previous experiments no conclusive results could be obtained. (orig.)

  17. Cellulose gels produced in room temperature ionic liquids by ionizing radiation

    International Nuclear Information System (INIS)

    Kimura, Atsushi; Nagasawa, Naotsugu; Taguchi, Mitsumasa

    2014-01-01

    Cellulose-based gels were produced in room temperature ionic liquids (RTILs) by ionizing radiation. Cellulose was dissolved at the initial concentration of 20 wt% in 1-ethyl-3-methylimidazolium (EMI)-acetate or N,N-diethyl-N-methyl-N-(2-methoxyethyl)ammonium (DEMA)-formate with a water content of 18 wt%, and irradiated with γ-rays under aerated condition to produce new cellulose gels. The gel fractions of the cellulose gels obtained in EMI-acetate and DEMA-formate at a dose of 10 kGy were 13% and 19%, respectively. The formation of gel fractions was found to depend on the initial concentration of cellulose, water content, and irradiation temperature. The obtained gel readily absorbed water, methanol, ethanol, dichloromethane, N,N-dimethylacetamide, and RTILs. - Highlights: • Cellulose gels were produced in room temperature ionic liquids (RTILs). • Water plays a crucial role in the cross-linking reaction. • Cellulose gels swollen with RTILs show good electronic conductivity (3.0 mS cm −1 )

  18. Formation of crystalline telluridomercurates from ionic liquids near room temperature

    Energy Technology Data Exchange (ETDEWEB)

    Donsbach, Carsten; Dehnen, Stefanie [Fachbereich Chemie und Wissenschaftliches Zentrum fuer Materialwissenschaften, Philipps-Universitaet Marburg, Hans-Meerwein-Strasse 4, 35043, Marburg (Germany)

    2017-01-15

    The ternary telluridomercurate Na{sub 2}[HgTe{sub 2}] (1) was formed by fusion of Na{sub 2}Te and HgTe at 600 C and further treated in the ionic liquid (C{sub 4}C{sub 1}Im)[BF{sub 4}] (C{sub 4}C{sub 1}Im = 1-butyl-3-methylimidazolium) at moderately elevated temperatures (60 C), leading to replacement of the Na{sup +} cations with (C{sub 4}C{sub 1}Im){sup +} and re-arrangement of the inorganic substructure. As a result, we obtained the telluridomercurate (C{sub 4}C{sub 1}Im){sub 2}[HgTe{sub 2}] (2) and the tellurido/ditelluridomercurate (C{sub 4}C{sub 1}Im){sub 2}[Hg{sub 2}Te{sub 4}] (3) besides polytellurides and HgTe as by-products. The heavy atom compositions of the compounds were confirmed by micro X-ray fluorescence spectroscopy (μ-XFS), and their structures were determined by single-crystal diffraction. The cation-exchanged salts were further investigated by UV/Vis spectroscopy, indicating narrow band-gap optical transitions at 2.80 eV (2) and 1.63 eV (3), in agreement with their visible yellow or reddish-black color, respectively. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  19. Proactive aquatic ecotoxicological assessment of room-temperature ionic liquids

    Science.gov (United States)

    Kulacki, K.J.; Chaloner, D.T.; Larson, J.H.; Costello, D.M.; Evans-White, M. A.; Docherty, K.M.; Bernot, R.J.; Brueseke, M.A.; Kulpa, C.F.; Lamberti, G.A.

    2011-01-01

    Aquatic environments are being contaminated with a myriad of anthropogenic chemicals, a problem likely to continue due to both unintentional and intentional releases. To protect valuable natural resources, novel chemicals should be shown to be environmentally safe prior to use and potential release into the environment. Such proactive assessment is currently being applied to room-temperature ionic liquids (ILs). Because most ILs are water-soluble, their effects are likely to manifest in aquatic ecosystems. Information on the impacts of ILs on numerous aquatic organisms, focused primarily on acute LC50 and EC50 endpoints, is now available, and trends in toxicity are emerging. Cation structure tends to influence IL toxicity more so than anion structure, and within a cation class, the length of alkyl chain substituents is positively correlated with toxicity. While the effects of ILs on several aquatic organisms have been studied, the challenge for aquatic toxicology is now to predict the effects of ILs in complex natural environments that often include diverse mixtures of organisms, abiotic conditions, and additional stressors. To make robust predictions about ILs will require coupling of ecologically realistic laboratory and field experiments with standard toxicity bioassays and models. Such assessments would likely discourage the development of especially toxic ILs while shifting focus to those that are more environmentally benign. Understanding the broader ecological effects of emerging chemicals, incorporating that information into predictive models, and conveying the conclusions to those who develop, regulate, and use those chemicals, should help avoid future environmental degradation. ?? 2011 Bentham Science Publishers Ltd.

  20. Glass Transitions and Low-Frequency Dynamics of Room-Temperature Ionic Liquids

    International Nuclear Information System (INIS)

    Yamamuro, O.; Inamura, Y.; Hayashi, S.; Hamaguchi, H.

    2006-01-01

    We have measured the heat capacity and neutrion quasi- and inelastic scattering spectra of some salts of 1-butyl-3-methylimidazolium ion bmim+, which is a typical cation of room-temperature ionic liquids, and its derivatives. The heat capacity measurements revealed that the room-temperature ionic liquids have glass transitions as molecular liquids. The temperature dependence of configurational entropy demonstrated that the room-temperature ionic liquids are 'fragile liquids'. Both heat capacity and inelastic neutron scattering data revealed that the glassy phases exhibit large low-energy excitations usually called 'boson peak'. The quasielastic neutron scattering data showed that so-called 'fast process' appears around Tg as in molecular and polymer glasses. The temperature dependence of the self-diffusion coefficient derived from the neutron scattering data indicated that the orientation of bmim+ ions and/or butyl-groups of bmim+ ions is highly disordered and very flexible in an ionic liquid phase

  1. Electrochemical applications of room temperature ionic liquids in nuclear fuel cycle

    International Nuclear Information System (INIS)

    Venkatesan, K.A.; Srinivasan, T.G.; Vasudeva Rao, P.R.

    2008-01-01

    Applications of room temperature ionic liquids (RTILs) have invaded all branches of science. They are also receiving an upsurge, in recent years, for possible applications in various stages of nuclear fuel cycle. Ionic liquids are compounds composed entirely of ions existing in liquid state and RTILs are ionic liquids molten at temperatures lower than 373 K. RTILs are generally made up of an organic cation and an inorganic or an organic anion. Room temperature ionic liquids have several fascinating properties, which are unique to a particular combination of cation and anion. The properties such as insignificant vapor pressure, amazing ability to dissolve organic and inorganic compounds, wide electrochemical window are the specific advantages when dealing with application of RTILs for reprocessing of spent nuclear fuel. The ionic liquids are regarded as designer or tailor-made solvents as their properties can be tuned for desired application by appropriate cation-anion combinations. An excellent review by Wilkes describes about the historical perspectives of room temperature ionic liquids, pioneers in that area, events and the products delivered till 2001. Furthermore, several comprehensive reviews have been made on room temperature ionic liquids by various authors

  2. Predicting critical temperatures of ionic and non-ionic fluids from thermophysical data obtained near the melting point

    Science.gov (United States)

    Weiss, Volker C.

    2015-10-01

    In the correlation and prediction of thermophysical data of fluids based on a corresponding-states approach, the critical temperature Tc plays a central role. For some fluids, in particular ionic ones, however, the critical region is difficult or even impossible to access experimentally. For molten salts, Tc is on the order of 3000 K, which makes accurate measurements a challenging task. Room temperature ionic liquids (RTILs) decompose thermally between 400 K and 600 K due to their organic constituents; this range of temperatures is hundreds of degrees below recent estimates of their Tc. In both cases, reliable methods to deduce Tc based on extrapolations of experimental data recorded at much lower temperatures near the triple or melting points are needed and useful because the critical point influences the fluid's behavior in the entire liquid region. Here, we propose to employ the scaling approach leading to universal fluid behavior [Román et al., J. Chem. Phys. 123, 124512 (2005)] to derive a very simple expression that allows one to estimate Tc from the density of the liquid, the surface tension, or the enthalpy of vaporization measured in a very narrow range of low temperatures. We demonstrate the validity of the approach for simple and polar neutral fluids, for which Tc is known, and then use the methodology to obtain estimates of Tc for ionic fluids. When comparing these estimates to those reported in the literature, good agreement is found for RTILs, whereas the ones for the molten salts NaCl and KCl are lower than previous estimates by 10%. The coexistence curve for ionic fluids is found to be more adequately described by an effective exponent of βeff = 0.5 than by βeff = 0.33.

  3. Cryo-transmission electron microscopy of Ag nanoparticles grown on an ionic liquid substrate

    KAUST Repository

    Anjum, Dalaver H.; Stiger, Rebecca M.; Finley, James J.; Conway, James F.

    2010-01-01

    We report a novel method of growing silver nanostructures by cathodic sputtering onto an ionic liquid (IL) and our visualization by transmission cryo-electron microscopy to avoid beam-induced motion of the nanoparticles. By freezing the IL

  4. Intermediate temperature ionic conductivity of Sm1.92Ca0.08Ti2O7–δ pyrochlore

    DEFF Research Database (Denmark)

    Eurenius, Karinh E. J.; Bentzer, Henrik Karnøe; Bonanos, Nikolaos

    2011-01-01

    (500–300 °C). The impedance measurements revealed the conductivity to be mainly ionic under all conditions, with the highest total conductivity measured being 0.045 S/m under wet oxygen at 500 °C. Both bulk and grain boundary conductivity was predominantly ionic, but electronic conductivity appeared...... to play a slightly larger part in the grain boundaries. EMF data confirmed the conductivity to be mainly ionic, with oxide ions being the major conducting species at 500 °C and protons becoming increasingly important below this temperature....

  5. Aluminium Electrodeposition from Ionic Liquid: Effect of Deposition Temperature and Sonication †

    Directory of Open Access Journals (Sweden)

    Enrico Berretti

    2016-08-01

    Full Text Available Since their discovery, ionic liquids (ILs have attracted a wide interest for their potential use as a medium for many chemical processes, in particular electrochemistry. As electrochemical media they allow the electrodeposition of elements that are impossible to reduce in aqueous media. We have investigated the electrodeposition of aluminium from 1-butyl-3-methyl-imidazolium chloride ((BmimCl/AlCl3 (40/60 mol % as concerns the effect of deposition parameters on the quality of the deposits. Thick (20 μm aluminium coatings were electrodeposited on brass substrates at different temperatures and mixing conditions (mechanical stirring and sonication. These coatings were investigated by means of scanning electron microscope, roughness measurements, and X-ray diffraction to assess the morphology and the phase composition. Finally, electrochemical corrosion tests were carried out with the intent to correlate the deposition parameters to the anti-corrosion properties.

  6. Ionic liquids and ionic liquid acids with high temperature stability for fuel cell and other high temperature applications, method of making and cell employing same

    Science.gov (United States)

    Angell, C Austen [Mesa, AZ; Xu, Wu [Broadview Heights, OH; Belieres, Jean-Philippe [Chandler, AZ; Yoshizawa, Masahiro [Tokyo, JP

    2011-01-11

    Disclosed are developments in high temperature fuel cells including ionic liquids with high temperature stability and the storage of inorganic acids as di-anion salts of low volatility. The formation of ionically conducting liquids of this type having conductivities of unprecedented magnitude for non-aqueous systems is described. The stability of the di-anion configuration is shown to play a role in the high performance of the non-corrosive proton-transfer ionic liquids as high temperature fuel cell electrolytes. Performance of simple H.sub.2(g) electrolyte/O.sub.2(g) fuel cells with the new electrolytes is described. Superior performance both at ambient temperature and temperatures up to and above 200.degree. C. are achieved. Both neutral proton transfer salts and the acid salts with HSO.sup.-.sub.4 anions, give good results, the bisulphate case being particularly good at low temperatures and very high temperatures. The performance of all electrolytes is improved by the addition of a small amount of involatile base of pK.sub.a value intermediate between those of the acid and base that make the bulk electrolyte. The preferred case is the imidazole-doped ethylammonium hydrogensulfate which yields behavior superior in all respects to that of the industry standard phosphoric acid electrolyte.

  7. Ab-Initio analysis of TlBr: limiting the ionic current without degrading the electronic one

    Science.gov (United States)

    Rocha Leao, Cedric; Lordi, Vincenzo

    2011-03-01

    Although TlBr in principle presents all the theoretical requirements for making high resolution room temperature radiation detectors, practical applications of TlBr have proven to be nonviable due to the polarization that is observed in the crystal after relatively short periods of operation. This polarization, that is believed to be caused by accumulation of oppositely charged ionic species at the ends of the crystal, results in an electric field that opposes that of the applied bias, counter-acting its effect. In this work, we use state of the art quantum modeling to benchmark the theoretical limits for the performance of TlBr as a radiation detector, showing that the best experimental reports demonstrate near-ideal electronic characteristics. We then propose a model to inhibit the detrimental ionic current in the material without impacting the excellent properties of the electronic current. Prepared by LLNL under Contract DE-AC52-07NA27344.

  8. Effect of temperature on the electronic/ionic transport properties of porous LiNi{sub 0.5}Mn{sub 1.5}O{sub 4} with high voltage for lithium ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Cui, Yongli, E-mail: lilyshuoxu@163.com; Wang, Mingzhen; Wang, Jiali; Zhuang, Quanchao, E-mail: zhuangquanchao@126.com

    2016-09-01

    Porous spinel LiNi{sub 0.5}Mn{sub 1.5}O{sub 4} microspheres were successfully synthesized by a facile method with microspheres MnCO{sub 3} template, and characterized by XRD and SEM. The as-synthesized porous LiNi{sub 0.5}Mn{sub 1.5}O{sub 4} microspheres exhibit high rate capability and good cycle performance, with the specific discharge capacity of 125.5, 125.4, 121 and 97.6 mA h/g at 1, 2, 3 and 5 C, respectively, and the capacity retention of 85.6% at 5 C after 100 cycles, which are attributed to the porous structure. It is found that the EIS features of spinel LiNi{sub 0.5}Mn{sub 1.5}O{sub 4} cathode are related to the temperature, and the middle to high frequency arc is observed in the Nyquist diagram at temperatures below zero, which is attributed to the electronic properties of the electrode material. In 1 mol/L LiPF{sub 6}-EC:DEC:DMC electrolyte solutions, the energy barriers for the ion jump related to migration of lithium ions through the SEI film of the spinel LiNi{sub 0.5}Mn{sub 1.5}O{sub 4} cathode are determined to be 16.89 kJ/mol, the thermal activation energy of the electronic conductivity to be 0.348 eV, and the intercalation-deintercalation reaction activation energies to be 0.619 eV, respectively. - Highlights: • Porous spinel LiNi{sub 0.5}Mn{sub 1.5}O{sub 4} microspheres cathode were synthesized. • Porous LiNi{sub 0.5}Mn{sub 1.5}O{sub 4} microspheres show high rate and excellent cycle characteristic. • The EIS features of spinel LiNi{sub 0.5}Mn{sub 1.5}O{sub 4} have related to temperature. • Three different energies of kinetic characterization at 4.7 V are calculated.

  9. Gas Transport Properties of PEBAX®/Room Temperature Ionic Liquid Gel Membranes

    Czech Academy of Sciences Publication Activity Database

    Bernardo, P.; Jansen, J. C.; Bazzarelli, F.; Tasselli, F.; Fuoco, A.; Friess, K.; Izák, Pavel; Jarmarová, Veronika; Kačírková, Marie; Clarizia, G.

    2012-01-01

    Roč. 97, SI (2012), s. 73-82 ISSN 1383-5866. [Conference on Ionic Liquids in Separation and Purification Technology (ILSEPT) /1./. Sitges, 04.09.2011-07.09.2011] R&D Projects: GA ČR GAP106/10/1194 Grant - others:RFCS(XE) RFCR-CT-2010-00009 Institutional support: RVO:67985858 Keywords : room temperature ionic liquid * ionic liquid * polymer gel Subject RIV: CI - Industrial Chemistry, Chemical Engineering Impact factor: 2.894, year: 2012

  10. Ruthenium(III Chloride Catalyzed Acylation of Alcohols, Phenols, and Thiols in Room Temperature Ionic Liquids

    Directory of Open Access Journals (Sweden)

    Mingzhong Cai

    2009-09-01

    Full Text Available Ruthenium(III chloride-catalyzed acylation of a variety of alcohols, phenols, and thiols was achieved in high yields under mild conditions (room temperature in the ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF6]. The ionic liquid and ruthenium catalyst can be recycled at least 10 times. Our system not only solves the basic problem of ruthenium catalyst reuse, but also avoids the use of volatile acetonitrile as solvent.

  11. Temperature-triggered micellization of block copolymers on an ionic liquid surface.

    Science.gov (United States)

    Lu, Haiyun; Akgun, Bulent; Wei, Xinyu; Li, Le; Satija, Sushil K; Russell, Thomas P

    2011-10-18

    In situ neutron reflectivity was used to study thermally induced structural changes of the lamellae-forming polystyrene-block-poly(2-vinylpyridine) (PS-b-P2VP) block copolymer thin films floating on the surface of an ionic liquid (IL). The IL, 1-butyl-3-methylimidazolium trifluoromethanesulfonate, is a nonsolvent for PS and a temperature-tunable solvent for P2VP, and, as such, micellization can be induced at the air-IL interface by changing the temperature. Transmission electron microscopy and scanning force microscopy were used to investigate the resultant morphologies of the micellar films. It was found that highly ordered nanostructures consisting of spherical micelles with a PS core surrounded by a P2VP corona were produced. In addition, bilayer films of PS homopolymer on top of a PS-b-P2VP layer also underwent micellization with increasing temperature but the micellization was strongly dependent on the thickness of the PS and PS-b-P2VP layers. © 2011 American Chemical Society

  12. Investigating the solvent and temperature effects on the cyclohexadienyl radical in an ionic liquid

    International Nuclear Information System (INIS)

    Taylor, Becky; Cormier, P.J.; Lauzon, J.M.; Ghandi, Khashayar

    2009-01-01

    The cyclohexadienyl radical was studied in a novel green solvent; tetradecyl (trihexyl) phosphonium chloride ionic liquid (IL 101). Both the solvent effects and how the hyperfine coupling changes with respect to temperature have been examined and compared to literature. This was done through experimental muon techniques at the TRIUMF National Laboratory in Canada as well as through ab initio calculations. The ionic liquid solvent effects were found to be consistent with other solvents, when assuming ionic liquids to be a combination of ion pairs. In ionic liquid the hyperfine coupling constants of the proton and reduced muon decreased linearly with increasing temperature. The analysis showed that the majority of this relationship is due to a vibrational effect, although the solvent density plays a role too. The temperature effect on the entropy of the system was determined to be negligible. The temperature coefficient of the reduced muon hyperfine coupling was larger than that of the proton in IL 101 due to the effects of nearby ionic liquid molecules.

  13. Investigating the solvent and temperature effects on the cyclohexadienyl radical in an ionic liquid

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, Becky; Cormier, P.J.; Lauzon, J.M. [Department of Chemistry, Mount Allison University, Sackville, New Brunswick, E4L 1G3 (Canada); Ghandi, Khashayar, E-mail: kghandi@mta.c [Department of Chemistry, Mount Allison University, Sackville, New Brunswick, E4L 1G3 (Canada)

    2009-04-15

    The cyclohexadienyl radical was studied in a novel green solvent; tetradecyl (trihexyl) phosphonium chloride ionic liquid (IL 101). Both the solvent effects and how the hyperfine coupling changes with respect to temperature have been examined and compared to literature. This was done through experimental muon techniques at the TRIUMF National Laboratory in Canada as well as through ab initio calculations. The ionic liquid solvent effects were found to be consistent with other solvents, when assuming ionic liquids to be a combination of ion pairs. In ionic liquid the hyperfine coupling constants of the proton and reduced muon decreased linearly with increasing temperature. The analysis showed that the majority of this relationship is due to a vibrational effect, although the solvent density plays a role too. The temperature effect on the entropy of the system was determined to be negligible. The temperature coefficient of the reduced muon hyperfine coupling was larger than that of the proton in IL 101 due to the effects of nearby ionic liquid molecules.

  14. Gas-liquid interface of room-temperature ionic liquids.

    Science.gov (United States)

    Santos, Cherry S; Baldelli, Steven

    2010-06-01

    The organization of ions at the interface of ionic liquids and the vacuum is an ideal system to test new ideas and concepts on the interfacial chemistry of electrolyte systems in the limit of no solvent medium. Whilst electrolyte systems have numerous theoretical and experimental methods used to investigate their properties, the ionic liquids are relatively new and our understanding of the interfacial properties is just beginning to be explored. In this critical review, the gas-liquid interface is reviewed, as this interface does not depend on the preparation of another medium and thus produces a natural interface. The interface has been investigated by sum frequency generation vibrational spectroscopy and ultra-high vacuum techniques. The results provide a detailed molecular-level view of the surface composition and structure. These have been complemented by theoretical studies. The combinations of treatments on this interface are starting to provide a somewhat convergent description of how the ions are organized at this neat interface (108 references).

  15. Wolte 5. low temperature electronics

    International Nuclear Information System (INIS)

    Balestra, F.; Dieudonne, F.; Jomaah, J.

    2002-01-01

    This book present the latest research and development results in advanced materials, technologies, devices, circuits and systems for low temperature electronics. The main themes of the papers are ranging from physics and fundamental aspects, modeling and simulation, to device and circuit design. The topics include advanced process and characterization, novel devices and cryogenic instrumentation. The papers are divided into nine sections, reflecting the main research efforts in different areas: i) deep submicron silicon MOSFETs, ii) alternative MOSFETs (SOI, innovating device architectures), iii) III-V devices, iv) other semiconductor devices (Ge devices, p-n junctions, IR sensors, semiconductor microcrystals), v) emerging devices and phenomena (nano Si-based devices, conduction and fluctuations mechanisms), vi) superconducting materials, vii) superconducting detectors, viii) superconducting devices and circuits (RSFQ, SIS mixers, metal-superconducting-semiconductor structures), ix) low temperature electronics for space applications. Six invited papers presented by internationally recognized authors, and 39 contributed papers are presented. The invited papers provide an excellent overview of today's status and progress, as well as tomorrow's challenges and trends in this important discipline for many cryogenic applications. (authors)

  16. Effect of room temperature ionic liquid structure on the enzymatic acylation of flavonoids

    DEFF Research Database (Denmark)

    Lue, Bena-Marie; Guo, Zheng; Xu, Xuebing

    2010-01-01

    Enzymatic acylation reactions of flavonoids (rutin, esculin) with long chain fatty acids (palmitic, oleic acids) were carried out in 14 different ionic liquid media containing a range of cation and anion structures. Classification of RTILs according to flavonoid solubility (using COSMO...... must be struck that maximized flavonoid solubility with minimum negative impact on lipase activity. The process also benefitted from an increased reaction temperature which may have helped to reduced mass transfer limitations. Keywords: Room temperature ionic liquids (RTILs); Biosynthesis; Acylation......; Flavonoids; Lipase; Long chain fatty acids...

  17. A review on the electrochemical applications of room temperature ionic liquids in nuclear fuel cycle

    International Nuclear Information System (INIS)

    Venkatesan, K.A.; Srinivasan, T.G.; Vasudeva Rao, P.R.

    2009-01-01

    A mini review on the electrochemical applications of room temperature ionic liquids (RTIL) in nuclear fuel cycle is presented. It is shown that how the fascinating properties of RTIL can be tuned to deliver desirable application in aqueous and non-aqueous reprocessing and in nuclear waste management. (author)

  18. Application of room temperature ionic liquids in advanced fuel cycles RIAR research concept program users

    International Nuclear Information System (INIS)

    Bychkov, Alexander V.; Kormilitsyn, Michael V.; Savochkin, Yuri P.; Osipenko, Alexander G.; Smolensky, Valeri V.; Shadrin, Alexander Yu.; Babain, Vladimir A.

    2005-01-01

    The paper reviews briefly the research program on application of Room Temperature Ionic Liquids (RTILs) in some processes of the nuclear fuel reprocessing, particularly in the uranium-aluminum fuel reprocessing and separation of TPEs and REEs from the PUREX process liquid waste, and approaches to implementation of this program. (author)

  19. Quantitative structure—property relationship for thermal decomposition temperature of ionic liquids

    DEFF Research Database (Denmark)

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

    2012-01-01

    In this study, a wide literature survey has been conducted to gather an extensive set of thermal decomposition temperature (Td) data for ionic liquids (ILs). A data set consisting of Td data for 586 ILs was collated from 71 different literature sources. Using this data set, a reliable quantitativ...

  20. Thermodynamics for proton binding of phytate in KNO3(aq) at different temperatures and ionic strengths

    International Nuclear Information System (INIS)

    Bretti, Clemente; De Stefano, Concetta; Lando, Gabriele; Sammartano, Silvio

    2013-01-01

    Highlights: • Protonation data were modeled in a wide range of temperatures and ionic strengths. • Protonation values decrease with increasing ionic strength and temperature. • In KNO 3 proton binding process is slightly exothermic, but less than in NaCl. • The major contribution for the proton association is entropic in nature. • Results are in agreement with previous findings for KCl and NaCl. - Abstract: Potentiometric measurements were performed in KNO 3(aq) , to determine the apparent protonation constants of phytate at different temperatures (278.15 ≤ T (K) ≤ 323.15) and ionic strengths (0.25 ≤ I (mol) dm −3 ≤ 3.0) values. In general, the protonation constants decrease with increasing both temperature and ionic strength. The data reported were critically compared with previous results obtained in KCl and the values are in a good agreement, considering the experimental errors and slight differences between the activity coefficients of the various species in KCl and KNO 3 . Experimental data were then modeled as a function of temperature and ionic strength using, with comparable results, two approaches: the extended Debye–Hückel equation and the specific ion interaction theory (SIT). The single specific ion interaction coefficients, ε, were also determined. The corresponding values are higher than those in Na + media. The protonation constants were also analyzed considering a simplified weak interaction model using an empirical equation that contains an additional term which takes into account the formation of weak complexes. The results obtained for the modeling of the protonation constants are in agreement with the literature findings. Thermodynamic protonation parameters were also obtained at different temperatures and ionic strengths. The proton association process is slightly exothermic and the enthalpic contribution is less negative than that in NaCl solution. As observed in other cases for phytate anion, the major contribution for

  1. Electronic structure and ionicity of actinide oxides from first principles

    DEFF Research Database (Denmark)

    Petit, Leon; Svane, Axel; Szotek, Z.

    2010-01-01

    The ground-state electronic structures of the actinide oxides AO, A2O3, and AO2 (A=U, Np, Pu, Am, Cm, Bk, and Cf) are determined from first-principles calculations, using the self-interaction corrected local spin-density approximation. Emphasis is put on the degree of f-electron localization, whi...

  2. Probing Ionic Liquid Aqueous Solutions Using Temperature of Maximum Density Isotope Effects

    Directory of Open Access Journals (Sweden)

    Mohammad Tariq

    2013-03-01

    Full Text Available This work is a new development of an extensive research program that is investigating for the first time shifts in the temperature of maximum density (TMD of aqueous solutions caused by ionic liquid solutes. In the present case we have compared the shifts caused by three ionic liquid solutes with a common cation—1-ethyl-3-methylimidazolium coupled with acetate, ethylsulfate and tetracyanoborate anions—in normal and deuterated water solutions. The observed differences are discussed in terms of the nature of the corresponding anion-water interactions.

  3. Communication: Anomalous temperature dependence of the intermediate range order in phosphonium ionic liquids

    International Nuclear Information System (INIS)

    Hettige, Jeevapani J.; Kashyap, Hemant K.; Margulis, Claudio J.

    2014-01-01

    In a recent article by the Castner and Margulis groups [Faraday Discuss. 154, 133 (2012)], we described in detail the structure of the tetradecyltrihexylphosphonium bis(trifluoromethylsulfonyl)-amide ionic liquid as a function of temperature using X-ray scattering, and theoretical partitions of the computationally derived structure function. Interestingly, and as opposed to the case in most other ionic-liquids, the first sharp diffraction peak or prepeak appears to increase in intensity as temperature is increased. This phenomenon is counter intuitive as one would expect that intermediate range order fades as temperature increases. This Communication shows that a loss of hydrophobic tail organization at higher temperatures is counterbalanced by better organization of polar components giving rise to the increase in intensity of the prepeak

  4. Electrochemically cathodic exfoliation of graphene sheets in room temperature ionic liquids N-butyl, methylpyrrolidinium bis(trifluoromethylsulfonyl)imide and their electrochemical properties

    International Nuclear Information System (INIS)

    Yang, Yingchang; Lu, Fang; Zhou, Zhou; Song, Weixin; Chen, Qiyuan; Ji, Xiaobo

    2013-01-01

    Graphical abstract: Electrochemically cathodic exfoliation of graphite into few-layer graphene sheets in room temperature ionic liquids (RTILs) N-butyl, methylpyrrolidinium bis(trifluoromethylsulfonyl)-imide (BMPTF 2 N). -- Highlights: • Few-layer graphene sheets were prepared through electrochemically cathodic exfoliation in room temperature ionic liquids. • The mechanism of cathodic exfoliation in ionic liquids was proposed. • The derived activated graphene sheets show enhanced electrochemical properties. -- Abstract: Electrochemically cathodic exfoliation in room temperature ionic liquids N-butyl, methylpyrrolidinium bis(trifluoromethylsulfonyl)-imide (BMPTF 2 N) has been developed for few-layer graphene sheets, demonstrating low levels of oxygen (2.7 at% of O) with a nearly perfect structure (I D /I G 2 N involves the intercalation of ionic liquids cation [BMP] + under highly negatively charge followed by graphite expansion. Porous activated graphene sheets were also obtained by activation of graphene sheets in KOH. Transmission electron microscopy, X-ray photoelectron spectroscopy and Raman spectroscopy were used to characterize these graphene materials. The electrochemical performances of the graphene sheets and porous activated graphene sheets for lithium-ion battery anode materials were evaluated using cyclic voltammetry, galvanostatic charge–discharge cycling, and electrochemical impedance spectroscopy

  5. Non-haloaluminate room-temperature ionic liquids in electrochemistry--a review.

    Science.gov (United States)

    Buzzeo, Marisa C; Evans, Russell G; Compton, Richard G

    2004-08-20

    Some twenty-five years after they first came to prominence as alternative electrochemical solvents, room temperature ionic liquids (RTILs) are currently being employed across an increasingly wide range of chemical fields. This review examines the current state of ionic liquid-based electrochemistry, with particular focus on the work of the last decade. Being composed entirely of ions and possesing wide electrochemical windows (often in excess of 5 volts), it is not difficult to see why these compounds are seen by electrochemists as attractive potential solvents. Accordingly, an examination of the pertinent properties of ionic liquids is presented, followed by an assessment of their application to date across the various electrochemical disciplines, concluding with an outlook viewing current problems and directions.

  6. An Unexpected Reaction between 5-Hydroxymethylfurfural and Imidazolium-Based Ionic Liquids at High Temperatures

    Directory of Open Access Journals (Sweden)

    Zongbao K. Zhao

    2011-10-01

    Full Text Available A new compound was detected during the production of 5-hydroxymethylfurfural (HMF from glucose and cellulose in the ionic liquid 1-butyl-3-methylimidazolium chloride ([Bmim]Cl at high temperatures. Further experiments found that it was derived from the reaction of HMF with [Bmim]Cl. The structure of new compound was established as 1-butyl-2-(5’-methyl-2’-furoylimidazole (BMI based on nuclear magnetic resonance and mass spectrometry analysis, and a possible mechanism for its formation was proposed. Reactions of HMF with other imidazolium-based ionic liquids were performed to check the formation of BMI. Our results provided new insights in terms of side reactions between HMF and imidazolium-based ionic liquids, which should be valuable for designing better processes for the production of furans using biomass and related materials.

  7. Design of a mixed ionic/electronic conducting oxygen transport membrane pilot module

    Energy Technology Data Exchange (ETDEWEB)

    Pfaff, E.M.; Kaletsch, A.; Broeckmann, C. [RWTH Aachen University, IWM, Aachen (Germany)

    2012-03-15

    In the last years, a lot of ceramic materials were developed that, at higher temperatures, have a high electrical conductivity and a high conductivity of oxygen ions. Such mixed ionic/electronic conductors can be used to produce high-purity oxygen. This work focuses on the realization of a pilot membrane module, with BSCF (Ba{sub 0.5}Sr{sub 0.5}Co{sub 0.8}Fe{sub 0.2}O{sub 3-{delta}}) perovskite selected as the membrane material. An amount of 500 kg of powder was industrially fabricated, spray-granulized and pressed into tubes. The best operation conditions concerning energy consumption were calculated, and a module reactor was designed operating at 850 C, with an air pressure of 15-20 bar on the feed site and a low vacuum of about 0.8 bar on the permeate site. Special emphasis was placed on joining alternatives for ceramic tubes in metallic bottoms. A first laboratory module was tested with a membrane area of 1 m{sup 2} and then advanced to a pilot module with 570 tubes and a capability of more than 300 000 L of pure oxygen per day. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  8. Ionic liquids influence on the surface properties of electron beam irradiated wood

    Energy Technology Data Exchange (ETDEWEB)

    Croitoru, Catalin [“Transilvania” University of Brasov, Product Design and Environment Department, 29 Eroilor Str., 500036, Brasov (Romania); Patachia, Silvia, E-mail: st.patachia@unitbv.ro [“Transilvania” University of Brasov, Product Design and Environment Department, 29 Eroilor Str., 500036, Brasov (Romania); Doroftei, Florica; Parparita, Elena; Vasile, Cornelia [“Petru Poni” Institute of Macromolecular Chemistry, Physical Chemistry of Polymers Department, 41A Gr. Ghica Voda Alley, Iasi (Romania)

    2014-09-30

    Highlights: • Wood veneers impregnated with three imidazolium-based ionic liquids and irradiated with electron beam were studied by FTIR-ATR, SEM/EDX, AFM, contact angle and image analysis. • ILs preserve the surface properties of the wood (surface energy, roughness, color) upon irradiation, in comparison with the reference wood, but the surface composition is changed by treatment with IL-s, mainly with 1-butyl-3-methylimidazolium tetrafluoroborate. • Under electron beam irradiation covalent bonding of the imidazolium moiety to wood determines a higher resistance to water penetration and spreading on the surface. - Abstract: In this paper, the influence of three imidazolium-based ionic liquids (1-butyl-3-methylimidazolium tetrafluoroborate, 1-butyl-3-methylimidazolium hexafluorophosphate and 1-hexyl-3-methylimidazolium chloride) on the structure and surface properties of sycamore maple (Acer pseudoplatanus) veneers submitted to electron beam irradiation with a dose of 50 kGy has been studied by using Fourier transform infrared spectroscopy, as well as image, scanning electron microscopy/SEM/EDX, atomic force microscopy and contact angle analysis. The experimental results have proven that the studied ionic liquids determine a better preservation of the structural features of wood (cellulose crystallinity index and lignin concentration on the surface) as well as some of surface properties such as surface energy, roughness, color upon irradiation with electron beam, in comparison with the reference wood, but surface composition is changed by treatment with imidazolium-based ionic liquids mainly with 1-butyl-3-methylimidazolium tetrafluoroborate. Also, under electron beam irradiation covalent bonding of the imidazolium moiety to wood determines a higher resistance to water penetration and spreading on the surface.

  9. Synthesis and characterization of new ionic and mixed ionic/electronic conductors

    Science.gov (United States)

    Romito, Kevin Gregory

    In a constantly growing and developing world, there is a great need to develop new forms of clean energy generation. Many solutions have been proposed to ameliorate these global concerns, which include fuel cell technology and new processes for reducing polluting chemicals in the atmosphere. These technologies are still in their infancy and require further development before becoming viable options. In the case of fuel cells, particularly solid oxide fuel cells, and CO 2 separation membranes, there is a need to develop ion conducting materials that are highly efficient, less costly to synthesize, and can perform strongly under many real-world conditions. The need for further developing these ion conductors is currently one of the most important final steps required to push these new technologies into the market. The research presented here focuses on the synthesis and characterization for several ion conductor systems intended for efficient energy conversion applications. Using a novel transient liquid phase sintering method, we demonstrate that it is possible to synthesize dense BaZr0.8Y 0.2O3-delta (BZY20) at 1300°C, a lower temperatures than previously reported, using barium gallate as a sintering flux. Focusing on a new family of oxide-ion conductors, Sr1-xK xSi1-yGeyO3-0.5x, gallium served as a replacement germanium in an effort to further increase the oxide-ion conductivity. Unfortunately, the replacement of Ge with Ga was found to decrease the overall oxide-ion conductivity and microstructural morphology. Through the addition of an Al2O3 layer to a porous silver matrix, we show that CO2 permeation flux density through a new MECC membrane can be enhanced as a result of improved retention of molten carbonate in the silver matrix. Pore size and distribution in the silver matrix were found to greatly depend on the concentration of Al2O 3 suspension.

  10. Electronic and ionic ordering in condensed matter plasmas

    International Nuclear Information System (INIS)

    March, N.H.

    1981-01-01

    Recent progress in treating phase transitions induced by Coulomb interactions is reviewed. This is done by appealing to simple models, and in particular to the one-component plasma, with its quantum-mechanical counterpart jellium. The relevance of the phase transition, to a body-centred-cubic crystal in the classical one-component plasma, to the freezing of liquid metals Na and K is stressed. By generalizing these arguments to a two-component system, regularities in the freezing of the molten alkali halides are understandable. Sublattice disorder in superionics, driven by Coulomb forces, is then discussed. Finally, the ordering of electrons in jellium, in the limit of complete degeneracy, is considered: evidence being presented for the existence of electron liquids in molten Na and K. (author)

  11. Fission-Product Separation Based on Room-Temperature Ionic-Liquids

    International Nuclear Information System (INIS)

    Hussey, Charles L.

    2005-01-01

    During the previous funding cycle for this project, we investigated the electrochemistry of Cs(I) in air and moisture-stable ionic liquids both with and without the addition of BOBCalixC6. These investigations revealed that the electrochemical windows of the dialkylimidazolium bis[(trifluoromethyl)sulfonyl]imide ionic liquids do not permit the direct electrochemical reduction of Cs(I), even when Hg electrodes are employed, because these organic cations are reduced at less negative potentials than Cs(I). However, Cs(I) coordinated by BOBCalixC6 can be electrolytically reduced to Cs(Hg) in tetraalkylammonium-based room-temperature ionic liquids such as tri-1-butylmethylammonium bis[(trifluoromethyl)sulfonyl]imide (Bu3MeN+Tf2N-) at Hg electrodes. Because this reduction process does not harm either the ionic liquid or the macrocycle, it is a promising method for recycling the cesium extraction system. The previous studies mentioned above were carried out under an inert atmosphere, i.e., in the absence of H2O and O2. However, it may not be economically feasible or even possible to carry out the recycling process in the absence of these contaminants during large-scale processing of aqueous tank waste. Thus, as described in our proposal, we have begun an investigation of the electrochemical recovery of Cs from the Bu3MeN+Tf2N- + BOBCalixC6 extraction system in an air atmosphere containing various amounts of water and oxygen. Our recent preliminary results were very surprising because they indicated that the electrochemical extraction process is relatively insensitive to the presence of small amounts of moisture even when the moisture content of the ionic liquid approaches 1000 ppm. Furthermore, we have found that the ''wet'' ionic liquid can be easily dehydrated under reduced pressure or by sparging with dry nitrogen gas without the need for heat or any other specialized treatment

  12. Extraction of lithium from salt lake brine using room temperature ionic liquid in tributyl phosphate

    International Nuclear Information System (INIS)

    Shi, Chenglong; Jia, Yongzhong; Zhang, Chao; Liu, Hong; Jing, Yan

    2015-01-01

    Highlights: • We proposed a new system for Li recovery from salt lake brine by extraction using an ionic liquid. • Cation exchange was proposed to be the mechanism of extraction followed in ionic liquid. • This ionic liquid system shown considerable extraction ability for lithium and the single extraction efficiency of lithium reached 87.28% under the optimal conditions. - Abstract: Lithium is known as the energy metal and it is a key raw material for preparing lithium isotopes which have important applications in nuclear energy source. In this work, a typical room temperature ionic liquid (RTILs), 1-butyl-3-methyl-imidazolium hexafluorophosphate ([C 4 mim][PF 6 ]), was used as an alternative solvent to study liquid/liquid extraction of lithium from salt lake brine. In this system, the ionic liquid, NaClO 4 and tributyl phosphate (TBP) were used as extraction medium, co-extraction reagent and extractant respectively. The effects of solution pH value, phase ratio, ClO 4 − amount and other factors on lithium extraction efficiency had been investigated. Optimal extraction conditions of this system include the ratio of TBP/IL at 4/1 (v/v), O/A at 2:1, n(ClO 4 − )/n(Li + ) at 2:1, the equilibration time of 10 min and unadjusted pH. Under the optimal conditions, the single extraction efficiency of lithium was 87.28% which was much higher than the conventional extraction system. Total extraction efficiency of 99.12% was obtained by triple-stage countercurrent extraction. Study on the mechanism revealed that the use of ionic liquid increased the extraction yield of lithium through cation exchange in this system. Preliminary results indicated that the use of [C 4 mim][PF 6 ] as an alternate solvent to replace traditional organic solvents (VOCs) in liquid/liquid extraction was very promising

  13. Engineering Mixed Ionic Electronic Conduction in La 0.8 Sr 0.2 MnO 3+ δ Nanostructures through Fast Grain Boundary Oxygen Diffusivity

    KAUST Repository

    Saranya, Aruppukottai M.

    2015-04-09

    © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. Nanoionics has become an increasingly promising field for the future development of advanced energy conversion and storage devices, such as batteries, fuel cells, and supercapacitors. Particularly, nanostructured materials offer unique properties or combinations of properties as electrodes and electrolytes in a range of energy devices. However, the enhancement of the mass transport properties at the nanoscale has often been found to be difficult to implement in nanostructures. Here, an artificial mixed ionic electronic conducting oxide is fabricated by grain boundary (GB) engineering thin films of La0.8Sr0.2MnO3+δ. This electronic conductor is converted into a good mixed ionic electronic conductor by synthesizing a nanostructure with high density of vertically aligned GBs with high concentration of strain-induced defects. Since this type of GBs present a remarkable enhancement of their oxide-ion mass transport properties (of up to six orders of magnitude at 773 K), it is possible to tailor the electrical nature of the whole material by nanoengineering, especially at low temperatures. The presented results lead to fundamental insights into oxygen diffusion along GBs and to the application of these engineered nanomaterials in new advanced solid state ionics devices such are micro-solid oxide fuel cells or resistive switching memories. An electronic conductor such as La0.8Sr0.2MnO3+δ is converted into a good mixed ionic electronic conductor by synthesizing a nanostructure with excellent electronic and oxygen mass transport properties. Oxygen diffusion highways are created by promoting a high concentration of strain-induced defects in the grain boundary region. This novel strategy opens the way for synthesizing new families of artificial mixed ionic-electronic conductors by design.

  14. The electrochemical reduction of the purines guanine and adenine at platinum electrodes in several room temperature ionic liquids

    International Nuclear Information System (INIS)

    Zanoni, Maria Valnice Boldrin; Rogers, Emma I.; Hardacre, Christopher; Compton, Richard G.

    2010-01-01

    The reduction of guanine was studied by microelectrode voltammetry in the room temperature ionic liquids (RTILs) N-hexyltriethylammonium bis (trifluoromethanesulfonyl) imide [N 6,2,2,2 ][N(Tf) 2 ], 1-butyl-3-methylimidazolium hexafluorosphosphate [C 4 mim][PF 6 ], N-butyl-N-methyl-pyrrolidinium bis(trifluoromethanesulfonyl)imide [C 4 mpyrr][N(Tf) 2 ], 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide [C 4 mim][N(Tf) 2 ], N-butyl-N-methyl-pyrrolidinium dicyanamide [C 4 mpyrr][N(NC) 2 ] and tris(P-hexyl)-tetradecylphosphonium trifluorotris(pentafluoroethyl)phosphate [P 14,6,6,6 ][FAP] on a platinum microelectrode. In [N 6,2,2,2 ][NTf 2 ] and [P 14,6,6,6 ][FAP], but not in the other ionic liquids studied, guanine reduction involves a one-electron, diffusion-controlled process at very negative potential to produce an unstable radical anion, which is thought to undergo a dimerization reaction, probably after proton abstraction from the cation of the ionic liquid. The rate of this subsequent reaction depends on the nature of the ionic liquid, and it is faster in the ionic liquid [P 14,6,6,6 ][FAP], in which the formation of the resulting dimer can be voltammetrically monitored at less negative potentials than required for the reduction of the parent molecule. Adenine showed similar behaviour to guanine but the pyrimidines thymine and cytosine did not; thymine was not reduced at potentials less negative than required for solvent (RTIL) decomposition while only a poorly defined wave was seen for cytosine. The possibility for proton abstraction from the cation in [N 6,2,2,2 ][NTf 2 ] and [P 14,6,6,6 ][FAP] is noted and this is thought to aid the electrochemical dimerization process. The resulting rapid reaction is thought to shift the reduction potentials for guanine and adenine to lower values than observed in RTILs where the scope for proton abstraction is not present. Such shifts are characteristic of so-called EC processes where reversible electron transfer

  15. Is the boundary layer of an ionic liquid equally lubricating at higher temperature?

    Science.gov (United States)

    Hjalmarsson, Nicklas; Atkin, Rob; Rutland, Mark W

    2016-04-07

    Atomic force microscopy has been used to study the effect of temperature on normal forces and friction for the room temperature ionic liquid (IL) ethylammonium nitrate (EAN), confined between mica and a silica colloid probe at 25 °C, 50 °C, and 80 °C. Force curves revealed a strong fluid dynamic influence at room temperature, which was greatly reduced at elevated temperatures due to the reduced liquid viscosity. A fluid dynamic analysis reveals that bulk viscosity is manifested at large separation but that EAN displays a nonzero slip, indicating a region of different viscosity near the surface. At high temperatures, the reduction in fluid dynamic force reveals step-like force curves, similar to those found at room temperature using much lower scan rates. The ionic liquid boundary layer remains adsorbed to the solid surface even at high temperature, which provides a mechanism for lubrication when fluid dynamic lubrication is strongly reduced. The friction data reveals a decrease in absolute friction force with increasing temperature, which is associated with increased thermal motion and reduced viscosity of the near surface layers but, consistent with the normal force data, boundary layer lubrication was unaffected. The implications for ILs as lubricants are discussed in terms of the behaviour of this well characterised system.

  16. Electrochemical characterization of Uranyl-TODGA complex in a room temperature ionic liquid

    International Nuclear Information System (INIS)

    Sengupta, Arijit; Murali, M.S.; Mohapatra, P.K.

    2014-01-01

    Room temperature ionic liquids are new materials finding extensive use in many applications such as syntheses, catalysis, electrochemistry etc. including separation science. Some of them are known as green solvents set to be environment-friendly. With a view to apply the favourable properties of these neoteric solvents to separation science in nuclear related fields such as reprocessing and waste remediation, electrochemical characterization of the metal ions encountered in above fields e.g. U(VI), Pu(IV), Np(IV), Am(III) etc. their complexes with the ligands often becomes necessary and useful. In the present piece of work, electrochemical characterization has been carried out by cyclic voltammetry of uranyl complex with one of the most promising trivalent actinide extractants, namely, tetraoctyldiglycolamide (TODGA) dissolved/extracted into a room temperature ionic liquid, 1-methyl-3-octyl imidazolium bis(trifluoro methylsulphonyl) imide (C 8 mimNTf 2 )

  17. Towards Molecular Dynamics Simulations of Chiral Room-Temperature Ionic Liquids

    Czech Academy of Sciences Publication Activity Database

    Lísal, Martin; Chval, Z.; Storch, Jan; Izák, Pavel

    2014-01-01

    Roč. 189, SI (2014), s. 85-94 ISSN 0167-7322 R&D Projects: GA ČR(CZ) GAP106/12/0569; GA MŠk LH12020 Institutional support: RVO:67985858 Keywords : chiral room-temperature ionic liquid * molecular dynamics simulation * non-polarizable fully flexible all-atom force field Subject RIV: CI - Industrial Chemistry, Chemical Engineering Impact factor: 2.515, year: 2014

  18. Effects of functional group substitution on electron spectra and solvation dynamics in a family of ionic liquids

    International Nuclear Information System (INIS)

    Wishart, James F.; Lall-Ramnarine, Sharon I.; Raju, Ravinder; Scumpia, Alexander; Bellevue, Sherly; Ragbir, Revans; Engel, Robert

    2005-01-01

    Ionic liquids containing ether-, alcohol- and alkyl-functionalized quaternary ammonium dications were studied by pulse radiolysis. Spectra on nanosecond timescales revealed that solvation of the excess electron is particularly slow in the case of the alcohol-derivatized ionic liquids. The blue shift of the electron spectrum to the customary 650 nm peak takes 25-40 ns at 21 deg. C. Comparison with the relaxation dynamics observed in viscous 1,2,6-trihydroxyhexane reveals the hindering effect of the ionic liquid lattice on hydroxypropyl side chain reorientation

  19. Ionic liquid pretreatment of poplar wood at room temperature: swelling and incorporation of nanoparticles.

    Science.gov (United States)

    Lucas, Marcel; Macdonald, Brian A; Wagner, Gregory L; Joyce, Stephen A; Rector, Kirk D

    2010-08-01

    Lignocellulosic biomass offers economic and environmental advantages over corn starch for biofuels production. However, its fractionation currently requires energy-intensive pretreatments, due to the lignin chemical resistance and complex cell wall structure. Recently, ionic liquids have been used to dissolve biomass at high temperatures. In this study, thin sections of poplar wood were swollen by ionic liquid (1-ethyl-3-methylimidazolium acetate) pretreatment at room temperature. The samples contract when rinsed with deionized water. The controlled expansion and contraction of the wood structure can be used to incorporate enzymes and catalysts deep into the wood structure for improved pretreatments and accelerated cellulose hydrolysis. As a proof of concept, silver and gold nanoparticles of diameters ranging from 20 to 100 nm were incorporated at depths up to 4 mum. Confocal surface-enhanced Raman images at different depths show that a significant number of nanoparticles were incorporated into the pretreated sample, and they remained on the samples after rinsing. Quantitative X-ray fluorescence microanalyses indicate that the majority of nanoparticle incorporation occurs after an ionic liquid pretreatment of less than 1 h. In addition to improved pretreatments, the incorporation of materials and chemicals into wood and paper products enables isotope tracing, development of new sensing, and imaging capabilities.

  20. Interaction of radionickel with diatomite as a function of pH, ionic strength and temperature

    International Nuclear Information System (INIS)

    Xue Wang

    2013-01-01

    Sequestration of Ni(II) on diatomite as a function of reaction time, pH, ionic strength, foreign ions and temperature were investigated by batch sorption technique. The results indicated that the sorption of Ni(II) on diatomite was quickly in the first contact time of 2 h and then slowly with increasing contact time. The interaction of Ni(II) with diatomite was strongly pH- and ionic strength-dependent at low pH values (i.e., which was dominated by ion exchange or outer-sphere surface complexation), while the pH-dependent and ionic strength-independent sorption at high pH suggested that inner-sphere or multinuclear surface complexation was the main sorption mechanism. With increasing temperature, the sorption of Ni(II) on diatomite increased and the experimental data were well fitted by Langmuir model. The sorption samples at pH 6.8 and 10.0 were also characterized by XPS spectroscopy, and the results suggested that Si atoms also participated in Ni(II) sorption on diatomite. The results are important to evaluate the physicochemical behavior of Ni(II) and other similar radionuclides and heavy metal ions in the environment. (author)

  1. High temperature electronic gain device

    International Nuclear Information System (INIS)

    McCormick, J.B.; Depp, S.W.; Hamilton, D.J.; Kerwin, W.J.

    1979-01-01

    An integrated thermionic device suitable for use in high temperature, high radiation environments is described. Cathode and control electrodes are deposited on a first substrate facing an anode on a second substrate. The substrates are sealed to a refractory wall and evacuated to form an integrated triode vacuum tube

  2. Solvation behaviour of L-leucine in aqueous ionic liquid at different temperatures: Volumetric approach

    Science.gov (United States)

    Sharma, Samriti; Sandarve, Sharma, Amit K.; Sharma, Meena

    2018-05-01

    For the investigation of interactions of L-leucine in aqueous solutions of an ionic liquid (1-butyl-3-methylimidazolium tetra fluoroborate [Bmim][BF4]) at atmospheric pressure over a temperature range of (293.15K to 313.16K), we use the volumetric approach. By using the density data we have calculated the apparent molar volume, VΦ, limiting apparent molar volume, V0Φ, the slope, Sv, partial molar volume of transfer, V0Φ,tr. The values of these acoustical parameters have been used for the interpretation of different interactions like hydrophilic-hydrophilic, hydrophilic-hydrophobic, ion hydrophilic, solute-solvent and solute-solute interactions in the amino acid and ionic liquid solutions.

  3. Synthesis, ionic conductivity, and thermal properties of proton conducting polymer electrolyte for high temperature fuel cell

    Energy Technology Data Exchange (ETDEWEB)

    Itoh, Takahito; Hamaguchi, Yohei; Uno, Takahiro; Kubo, Masataka [Department of Chemistry for Materials, Faculty of Engineering, Mie University, 1577 Kurima Machiya-cho, Tsu, Mie 514-8507 (Japan); Aihara, Yuichi; Sonai, Atsuo [Samsung Yokohama Research Institute, 2-7 Sugasawa-cho, Tsurumi-ku, Yokohama 230-0027 (Japan)

    2006-01-16

    Hyperbranched polymer (poly-1a) with sulfonic acid groups at the end of chains was successfully synthesized. Interpenetration reaction of poly-1a with a hyperbranched polymer with acryloyl groups at the end of chains (poly-1b) as a cross-linker afforded a tough electrolyte membrane. The poly-1a and the resulting electrolyte membrane showed the ionic conductivities of 7x10{sup -4} and 8x10{sup -5} S/cm, respectively, at 150C under dry condition. The ionic conductivities of the poly-1a and the electrolyte membrane exhibited the VTF type temperature dependence. And also, both poly-1a and the resulting electrolyte membrane were thermally stable up to 200C. (author)

  4. Thermophysical and spectroscopic studies of room temperature ionic liquid, 1-butyl-3-methylimidazolium hexafluorophosphate in Tritons

    International Nuclear Information System (INIS)

    Chaudhary, Ganga Ram; Bansal, Shafila; Mehta, S.K.; Ahluwalia, A.S.

    2012-01-01

    Highlights: ► Thermophysical studies of new formulations of [BMIM][PF 6 ]+TX(45,100) have been made. ► Strong intermolecular interactions between [BMIM][PF 6 ] and TX (45, 100) is observed. ► Magnitude of interactions increases with the addition of oxyethylene groups in TX. ► With rise in temperature, intermolecular interactions increases. ► Spectroscopic studies show that interactions are via aromatic rings of RTIL and TX. - Abstract: The thermophysical properties viz. density ρ, speed of sound u, and specific conductivity κ of pure room temperature ionic liquid (1-butyl-3-methylimidazolium hexafluorophosphate) and its binary formulations with Triton X-45 and Triton X-100 have been studied over the entire composition range at different temperatures (293.15 to 323.15) K. Excess molar volume V E , deviation in isentropic compressibility ΔK S , partial molar excess volume V i E , deviation in partial molar isentropic compressibility ΔK S,i , deviation in specific conductivity Δκ have also been estimated and analysed. Spectroscopic properties (IR, 1 H and 13 C NMR) of these mixtures have been investigated in order to understand the structural and interactional behaviour of formulations studied. The magnitude of interactions between the two components increases with addition of number of oxyethylene groups in Tritons and with rise in temperature. Spectroscopic measurements indicate that interactions are mainly taking place through the five member ring of room temperature ionic liquid and six member ring of Tritons.

  5. Fission-Product Separation Based on Room-Temperature Ionic Liquids. Final Report

    International Nuclear Information System (INIS)

    Hussey, Charles L.

    2008-01-01

    During previous DOE sponsored research (DE-FG07-01ER63286), a process was developed for removing Cs+ and Sr2+ from simulated aqueous tank waste by extraction of these ions into a hydrophobic room-temperature ionic liquid solvent, tri-n-butylmethylammonium bis((trifluoromethyl)sulfonyl)imide, containing the ionophores, calix(4)arene-bis(tert-octylbenzo-crown-6) and dicyclohexano-18-crown-6. The coordinated Cs+ and Sr2+ could be removed from the ionic liquid extraction solvent by an electrochemical reduction process carried out at mercury electrodes. In this follow-up project, the effects of residual moisture and oxygen on this processing scheme were assessed. It was determined that the electrochemical reduction of ionophore-bound Cs+ at Hg electrodes is surprisingly tolerant of small amounts of water, but greatly affected by oxygen. However, sparging of the ionic liquid with dry N2 lowers the residual water and oxygen content of the extraction solvent to the level where the reduction of Cs+ at Hg is possible. Thus, the entire treatment cycle for the removal of Cs+ from tank waste using this approach can be carried out in an open cell, provided that the cell is continuously sparged with dry N2. (Due to a reduction in the funds designated for the project, it was not possible to investigate the effects of moisture and oxygen on the Sr2+ removal process.) Additional research carried out under this project led to the discovery and characterization of a new low-melting urea-based melt that can be used as an electrochemical solvent. This melt is less expensive to prepare than most of the well-know room-temperature ionic liquid solvents, has a better electrochemical window than existing urea-based melts, and has potential applications for the processing of nuclear waste. This melt is made by combining urea with the N,N-dialkylimidazolium salt, 1-ethyl-3-methylimidazolium chloride.

  6. Morphology, optical and ionic conductivity studies of electron beam irradiated polymer electrolyte film

    Science.gov (United States)

    Devendrappa, H.; Yesappa, L.; Niranjana, M.; Ashokkumar, S. P.; Vijeth, H.; Ganesh, S.

    2018-04-01

    The effects of electron beam (EB) irradiation on morphology, optical properties and ionic conductivity of (PVdF-co-HFP: LiClO4=90:10, PHL10) electrolyte films. The FESEM image reveal increasing porous morphology with increasing EB dose confirms the polymer degradation as result more amorphousity. The optical absorbance was found to be increase with red shift in UV region and direct optical band gaps was found decreased upon EB dose from 3.70 eV to 2.65 eV. The ionic conductivity increases slowly in lower frequency, whereas rapidly increases at the high frequency and found about 8.28×10-4 S/cm at 120 kGy dose. The obtained results suggest that the physical properties of polymer electrolytes can be changed using EB irradiation as requirement.

  7. Electron density analysis of 1-butyl-3-methylimidazolium chloride ionic liquid.

    Science.gov (United States)

    del Olmo, Lourdes; Morera-Boado, Cercis; López, Rafael; García de la Vega, José M

    2014-06-01

    An analysis of the electron density of different conformers of the 1-butyl-3-methylimidazolium chloride (bmimCl) ionic liquid by using DFT through the BVP86 density functional has been obtained within the framework of Bader's atom in molecules (AIM), localized orbital locator (LOL), natural bond orbital (NBO), and deformed atoms in molecules (DAM). We also present an analysis of the reduced density gradients that deliver the non-covalent interaction regions and allow to understand the nature of intermolecular interactions. The most polar conformer can be characterized as ionic by AIM, LOL, and DAM methods while the most stable and the least polar shows shared-type interactions. The NBO method allows to comprehend what causes the stabilization of the most stable conformer based on analysis of the second-order perturbative energy and the charge transferred among the natural orbitals involved in the interaction.

  8. Tuning the electrodeposition parameters of silver to yield micro/nano structures from room temperature protic ionic liquids

    International Nuclear Information System (INIS)

    Suryanto, Bryan H.R.; Gunawan, Christian A.; Lu Xunyu; Zhao Chuan

    2012-01-01

    Controlled electrodeposition of silver onto glassy carbon, gold and indium tin oxide-coated glass substrates has been achieved from three room temperature protic ionic liquids (PILs), ethylammonium nitrate, triethylammonium methylsulfonate, and bis(2-methoxyethyl)ammonium acetate. Cyclic voltammetric, chronoamperometric, together with microscopic and X-ray techniques reveal that micro/nanostructured Ag thin films of controlled morphology, size, density, and uniformity can be achieved by tuning the electrodeposition parameters such as potential, time, types of PILs, substrate materials, and ionic liquid viscosity by altering the water content. Chronoamperometric results provide direct evidence that electrodeposition of Ag in protic ionic liquids takes place through a progressive nucleation and diffusion-controlled 3D growth mechanism. The as prepared Ag micro/nanoparticles have been employed as electrocatalysts for oxygen reduction reaction and exhibit excellent catalytic activity. The study provides promise for using protic ionic liquids as alternative electrolytes to conventional aprotic ionic liquids for electrodeposition of metals and nanostructured electrocatalysts.

  9. Room temperature ionic liquids: A simple model. Effect of chain length and size of intermolecular potential on critical temperature.

    Science.gov (United States)

    Chapela, Gustavo A; Guzmán, Orlando; Díaz-Herrera, Enrique; del Río, Fernando

    2015-04-21

    A model of a room temperature ionic liquid can be represented as an ion attached to an aliphatic chain mixed with a counter ion. The simple model used in this work is based on a short rigid tangent square well chain with an ion, represented by a hard sphere interacting with a Yukawa potential at the head of the chain, mixed with a counter ion represented as well by a hard sphere interacting with a Yukawa potential of the opposite sign. The length of the chain and the depth of the intermolecular forces are investigated in order to understand which of these factors are responsible for the lowering of the critical temperature. It is the large difference between the ionic and the dispersion potentials which explains this lowering of the critical temperature. Calculation of liquid-vapor equilibrium orthobaric curves is used to estimate the critical points of the model. Vapor pressures are used to obtain an estimate of the triple point of the different models in order to calculate the span of temperatures where they remain a liquid. Surface tensions and interfacial thicknesses are also reported.

  10. Temperature Dependence on Density, Viscosity, and Electrical Conductivity of Ionic Liquid 1-Ethyl-3-Methylimidazolium Fluoride

    Directory of Open Access Journals (Sweden)

    Fengguo Liu

    2018-03-01

    Full Text Available Ionic liquids are considered environmentally friendly media for various industrial applications. Basic data on physicochemical properties are significant for a new material, in terms of developing its potential applications. In this work, 1-ethyl-3-methylimidazolium fluoride ([EMIm]F ionic liquid was synthesized via an anion metathesis process. Physical properties including the density, viscosity, electrical conductivity, and thermal stability of the product were measured. The results show that the density of [EMIm]F decreases linearly with temperature increases, while dynamic viscosity decreases rapidly below 320 K and the temperature dependence of electrical conductivity is in accordance with the VFT (Vogel–Fulcher–Tammann equation. The temperature dependence of the density, conductivity, and viscosity of [EMIm]F can be expressed via the following equations: ρ = 1.516 − 1.22 × 10−3 T, σm = 4417.1exp[−953.17/(T − 166.65] and η = 2.07 × 10−7exp(−5.39 × 104/T, respectively. [EMIm]F exhibited no clear melting point. However, its glass transition point and decomposition temperature are −71.3 °C and 135 °C, respectively.

  11. Extraction of lithium from salt lake brine using room temperature ionic liquid in tributyl phosphate

    Energy Technology Data Exchange (ETDEWEB)

    Shi, Chenglong [Key Laboratory of Salt Lake Resources and Chemistry, Qinghai Institute of Salt Lakes, Chinese Academy of Sciences, 810008 Xining (China); University of Chinese Academy of Sciences, 100049 Beijing (China); Jia, Yongzhong [Key Laboratory of Salt Lake Resources and Chemistry, Qinghai Institute of Salt Lakes, Chinese Academy of Sciences, 810008 Xining (China); Zhang, Chao [Key Laboratory of Salt Lake Resources and Chemistry, Qinghai Institute of Salt Lakes, Chinese Academy of Sciences, 810008 Xining (China); University of Chinese Academy of Sciences, 100049 Beijing (China); Liu, Hong [Qinghai Salt Chemical Products Supervision and Inspection Center, 816000 Golmud (China); Jing, Yan, E-mail: 1580707906@qq.com [Key Laboratory of Salt Lake Resources and Chemistry, Qinghai Institute of Salt Lakes, Chinese Academy of Sciences, 810008 Xining (China)

    2015-01-15

    Highlights: • We proposed a new system for Li recovery from salt lake brine by extraction using an ionic liquid. • Cation exchange was proposed to be the mechanism of extraction followed in ionic liquid. • This ionic liquid system shown considerable extraction ability for lithium and the single extraction efficiency of lithium reached 87.28% under the optimal conditions. - Abstract: Lithium is known as the energy metal and it is a key raw material for preparing lithium isotopes which have important applications in nuclear energy source. In this work, a typical room temperature ionic liquid (RTILs), 1-butyl-3-methyl-imidazolium hexafluorophosphate ([C{sub 4}mim][PF{sub 6}]), was used as an alternative solvent to study liquid/liquid extraction of lithium from salt lake brine. In this system, the ionic liquid, NaClO{sub 4} and tributyl phosphate (TBP) were used as extraction medium, co-extraction reagent and extractant respectively. The effects of solution pH value, phase ratio, ClO{sub 4}{sup −} amount and other factors on lithium extraction efficiency had been investigated. Optimal extraction conditions of this system include the ratio of TBP/IL at 4/1 (v/v), O/A at 2:1, n(ClO{sub 4}{sup −})/n(Li{sup +}) at 2:1, the equilibration time of 10 min and unadjusted pH. Under the optimal conditions, the single extraction efficiency of lithium was 87.28% which was much higher than the conventional extraction system. Total extraction efficiency of 99.12% was obtained by triple-stage countercurrent extraction. Study on the mechanism revealed that the use of ionic liquid increased the extraction yield of lithium through cation exchange in this system. Preliminary results indicated that the use of [C{sub 4}mim][PF{sub 6}] as an alternate solvent to replace traditional organic solvents (VOCs) in liquid/liquid extraction was very promising.

  12. Free electrons and ionic liquids: study of excited states by means of electron-energy loss spectroscopy and the density functional theory multireference configuration interaction method.

    Science.gov (United States)

    Regeta, Khrystyna; Bannwarth, Christoph; Grimme, Stefan; Allan, Michael

    2015-06-28

    The technique of low energy (0-30 eV) electron impact spectroscopy, originally developed for gas phase molecules, is applied to room temperature ionic liquids (IL). Electron energy loss (EEL) spectra recorded near threshold, by collecting 0-2 eV electrons, are largely continuous, assigned to excitation of a quasi-continuum of high overtones and combination vibrations of low-frequency modes. EEL spectra recorded by collecting 10 eV electrons show predominantly discrete vibrational and electronic bands. The vibrational energy-loss spectra correspond well to IR spectra except for a broadening (∼0.04 eV) caused by the liquid surroundings, and enhanced overtone activity indicating a contribution from resonant excitation mechanism. The spectra of four representative ILs were recorded in the energy range of electronic excitations and compared to density functional theory multireference configuration interaction (DFT/MRCI) calculations, with good agreement. The spectra up to about 8 eV are dominated by π-π* transitions of the aromatic cations. The lowest bands were identified as triplet states. The spectral region 2-8 eV was empty in the case of a cation without π orbitals. The EEL spectrum of a saturated solution of methylene green in an IL band showed the methylene green EEL band at 2 eV, indicating that ILs may be used as a host to study nonvolatile compounds by this technique in the future.

  13. Determination of electron temperature and electron density in ...

    African Journals Online (AJOL)

    It is seen that the electron temperature increases from 5.8 × 102 oK to 7.83 × 104 oK as the pd is reduced from 130mm Hg × mm to 60 mm Hg × mm for argon. The electron densities increases from 2.8 × 1011/cm3 to 3.2 × 1011 /cm3 for the same variation of pds. For air the electron temperature increases from 3.6 × 104 oK to ...

  14. Obtaining of lysozyme spherulitic forms at ambient temperature using pyrrolidinium octanoat as ionic liquid additive

    Directory of Open Access Journals (Sweden)

    Claudia Simona ŞTEFAN

    2012-12-01

    Full Text Available Pyrrolidinium octanoate carboxylate (Py+CnH2n+1COO-; PyO in abbreviation was used as additive for advanced crystallization of Lysozyme protein, to investigate the impact of protic ionic liquid on the protein crystal morphology. The ionic liquid was synthesized by acidic-base Brönsted neutralization, and its purity was checked by HPLC. The protein crystallization was made through the method of vapour diffusion with hanging drops. Crystallization experiments of Lysozyme with the addition of PyO were performed at 0.4 M PyO and respectively 1.6 M. The morphological of spherulitic forms of Lysozyme in aqueous solutions of PyO protic ionic liquid was investigated by optical microscopy after trials were incubated at ambient temperature (18-20°C, in various growth periods (3 days and 1 week. Hanging-drop vapour diffusion crystallization experiments with the addition of 0.4 M of PyO show that Lysozyme crystallized in type I spherulitic form. This is assumed to be a result of heterogeneous nucleation, with thin needles radially growing outwardfrom a more or less spherical particle. Hanging-drop vapour diffusioncrystallization experiments revealed that the addition of 1.6 M of PyO led to a second type of spherulitic form of the Lysozyme.

  15. Nanoscale organization in the fluorinated room temperature ionic liquid: Tetraethyl ammonium (trifluoromethanesulfonyl)(nonafluorobutylsulfonyl)imide

    Science.gov (United States)

    Lo Celso, F.; Appetecchi, G. B.; Jafta, C. J.; Gontrani, L.; Canongia Lopes, J. N.; Triolo, A.; Russina, O.

    2018-05-01

    Fluorinated Room Temperature Ionic Liquids (FRTILs) are a branch of ionic liquids that is the object of growing interest for a wide range of potential applications, due to the synergic combination of specifically ionic features and those properties that stem from fluorous tails. So far limited experimental work exists on the micro- and mesoscopic structural organization in this class of compounds. Such a work is however necessary to fully understand morphological details at atomistic level that would have strong implications in terms of bulk properties. Here we use the synergy between X-ray and neutron scattering together with molecular dynamics simulations to access structural details of a technologically relevant FRTIL that is characterised by an anion bearing a long enough fluorinated tail to develop specific morphological features. In particular, we find the first experimental evidence that in FRTILs bearing an asymmetric bis(perfluoroalkyl)sulfonyl-imide anion, fluorous side chains tend to be spatially segregated into nm-scale spatial heterogeneities. This feature together with the well-established micro-segregation of side alkyl chains in conventional RTILs leads to the concept of triphilic ILs, whose technological applications are yet to be fully developed.

  16. Electronic ceramics in high-temperature environments

    International Nuclear Information System (INIS)

    Searcy, A.W.; Meschi, D.J.

    1982-01-01

    Simple thermodynamic means are described for understanding and predicting the influence of temperature changes, in various environments, on electronic properties of ceramics. Thermal gradients, thermal cycling, and vacuum annealing are discussed, as well as the variations of ctivities and solubilities with temperature. 7 refs

  17. Electrodeposition of platinum nanoparticles in a room-temperature ionic liquid.

    Science.gov (United States)

    Zhang, Da; Chang, Wan Cheng; Okajima, Takeyoshi; Ohsaka, Takeo

    2011-12-06

    The electrochemistry of the [PtCl(6)](2-)-[PtCl(4)](2-)-Pt redox system on a glassy carbon (GC) electrode in a room-temperature ionic liquid (RTIL) [i.e., N,N-diethyl-N-methyl-N-(2-methoxyethyl)ammonium tetrafluoroborate (DEMEBF(4))] has been examined. The two-step four-electron reduction of [PtCl(6)](2-) to Pt, i.e., reduction of [PtCl(6)](2-) to [PtCl(4)](2-) and further reduction of [PtCl(4)](2-) to Pt, occurs separately in this RTIL in contrast to the one-step four-electron reduction of [PtCl(6)](2-) to Pt in aqueous media. The cathodic and anodic peaks corresponding to the [PtCl(6)](2-)/[PtCl(4)](2-) redox couple were observed at ca. -1.1 and 0.6 V vs a Pt wire quasi-reference electrode, respectively, while those observed at -2.8 and -0.5 V were found to correspond to the [PtCl(4)](2-)/Pt redox couple. The disproportionation reaction of the two-electron reduction product of [PtCl(6)](2-) (i.e., [PtCl(4)](2-)) to [PtCl(6)](2-) and Pt metal was also found to occur significantly. The electrodeposition of Pt nanoparticles could be carried out on a GC electrode in DEMEBF(4) containing [PtCl(6)](2-) by holding the potential at -3.5 or -2.0 V. At -3.5 V, the four-electron reduction of [PtCl(6)](2-) to Pt can take place, while at -2.0 V the two-electron reduction of [PtCl(6)](2-) to [PtCl(4)](2-) occurs. The results obtained demonstrate that the electrodeposition of Pt at -3.5 V may occur via a series of reductions of [PtCl(6)](2-) to [PtCl(4)](2-) and further [PtCl(4)](2-) to Pt and at -2.0 V via a disproportionation reaction of [PtCl(4)](2-) to [PtCl(6)](2-) and Pt. Furthermore, the deposition potential of Pt nanoparticles was found to largely influence their size and morphology as well as the relative ratio of Pt(110) and Pt(100) crystalline orientation domains. The sizes of the Pt nanoparticles prepared by holding the electrode potential at -2.0 and -3.5 V are almost the same, in the range of ca. 1-2 nm. These small nanoparticles are "grown" to form bigger

  18. Combined techniques for studying actinide complexes in room temperature ionic liquids

    International Nuclear Information System (INIS)

    Gaillard, C.; Billard, I.; Mekki, S.; Ouadi, A.; Hennig, Ch.; Denecke, M.A.

    2007-01-01

    Room temperature ionic liquids (RTILs) are a new class of solvents. Their main interest is related to their 'green' properties (non-volatile, non-flammable, etc.), but also from the variability of their physico-chemical properties (stability, hydrophobicity, viscosity) as a function of the RTIL cationic and anionic components. In the frame of the nuclear fuel reprocessing, RTILs are particularly attractive in order to improve existing processes or to develop new ones for actinide and lanthanide partitioning, in replacement of toxic solvents used nowadays, for metal electrodeposition or for liquid/liquid extraction by the use of task specific ionic liquids. However, despite the increasing number of publications devoted to ionic liquids, the solvation effects, the solute-solvent and solvent-solvent interactions are still hardly known. These fundamental aspects are of tremendous importance to the understanding of the solvating properties of these new solvents. In this frame, we have undertaken studies on the solvation and complexation of lanthanides (III) and actinides in RTILs, by the use of spectroscopic techniques. Experiments were led in various ionic liquids in order to highlight the role of the anionic part of the RTILs on the reactivity of the studied cations. Results have clearly shown that solvation phenomena in RTILs are not as 'simple' as in classical solvents. The dissolution of a Ln/An salt, even if complete, does not imply dissociation and solvation of the metal cation by the RTILs anions only. The nature of first co-ordination sphere of Ln/An depends on the competition between its counter-anions and the RTIL anions, which, in turn, influence the complexation reaction with other added anions such as chlorides. (authors)

  19. Electrochemical preparation of photoelectrochemically active CuI thin films from room temperature ionic liquid

    International Nuclear Information System (INIS)

    Huang, Hsin-Yi; Chien, Da-Jean; Huang, Genin-Gary; Chen, Po-Yu

    2012-01-01

    Highlights: ► CuI film can be formed by anodization of Cu in ionic liquid containing iodide. ► Coordinating strength of anion in ionic liquid determine the formation of CuI. ► Photocurrent of the CuI film can be observed in aqueous solution and in ionic liquid. ► Cu layer coated on conductive substrates can be converted to CuI. - Abstract: Cuprous iodide (CuI) thin films with photoelectrochemical activity were prepared by anodizing copper wire or copper-electrodeposited tungsten wire in the room temperature ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate (BMI-PF 6 RTIL) containing N-butyl-N-methylpyrrolidinium iodide (BMP-I). A copper coating was formed on the tungsten wire by potentiostatic electrodeposition in BMP-dicyanamide (BMP-DCA) RTIL containing copper chloride (CuCl). The CuI films formed using this method were compact, fine-grained and exhibited good adhesion. The characteristic diffraction signals of CuI were observed by powder X-ray diffractometry (XRD). X-ray photoelectron spectroscopy (XPS) also confirmed the formation of a CuI compound semiconductor. The CuI films demonstrated an apparent and stable photocurrent under white light illumination in aqueous solutions and in a RTIL. This method has enabled the electrochemical formation of CuI from a RTIL for the first time, and the first observation of a photocurrent produced from CuI in a RTIL. The coordinating strength of the anions of the RTIL is the key to the successful formation of the CuI thin film. If the coordinating strength of the anions of the RTIL is too strong, no CuI formation is observed.

  20. Parametric dependencies of JET electron temperature profiles

    Energy Technology Data Exchange (ETDEWEB)

    Schunke, B [Commission of the European Communities, Abingdon (United Kingdom). JET Joint Undertaking; Imre, K; Riedel, K [New York Univ., NY (United States)

    1994-07-01

    The JET Ohmic, L-Mode and H-Mode electron temperature profiles obtained from the LIDAR Thomson Scattering Diagnostic are parameterized in terms of the normalized flux parameter and a set of the engineering parameters like plasma current, toroidal field, line averages electron density... It is shown that the electron temperature profiles fit a log-additive model well. It is intended to use the same model to predict the profile shape for D-T discharges in JET and in ITER. 2 refs., 5 figs.

  1. Deep Trek High Temperature Electronics Project

    Energy Technology Data Exchange (ETDEWEB)

    Bruce Ohme

    2007-07-31

    This report summarizes technical progress achieved during the cooperative research agreement between Honeywell and U.S. Department of Energy to develop high-temperature electronics. Objects of this development included Silicon-on-Insulator (SOI) wafer process development for high temperature, supporting design tools and libraries, and high temperature integrated circuit component development including FPGA, EEPROM, high-resolution A-to-D converter, and a precision amplifier.

  2. Effect of temperature on the physical properties of two ionic liquids

    International Nuclear Information System (INIS)

    Pereiro, Ana B.; Veiga, Helena I.M.; Esperanca, Jose M.S.S.; Rodriguez, Ana

    2009-01-01

    Density, speed of sound, refractive index, and dynamic viscosity of the ionic liquids (ILs) 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide, BMpyr NTf 2 , and trihexyl(tetradecyl) phosphonium dicyanamide, P 66614 dca, were studied as a function of temperature at atmospheric pressure. Thermal expansion coefficient, α p , molecular volumes, and standard entropies of these ILs were calculated from the experimental density values. The solubility of three aromatic components (benzene, toluene, and ethylbenzene) in the selected ILs was carried out at T = 298.15 K and atmospheric pressure and compared with literature values for sulfolane.

  3. Antiwear performance of ionic liquid+graphene dispersions with anomalous viscosity-temperature behavior

    OpenAIRE

    Pamies Porras, Ramón Francisco; Arias Pardilla, Joaquín; Espinosa Rodríguez, Tulia; Carrión Vilches, Francisco José; Bermúdez Olivares, María Dolores; Sanes Molina, José; Avilés González, María Dolores

    2018-01-01

    New dispersions of few-layers graphene (G) in 1-ethyl-3-methylimidazolium ([EMIM]) ionic liquids (ILs) with dicyanamide ([DCA]) or bis(trifluoromethylsulfonyl)imide ([TFSI]) anions have been obtained by mechanical mixing and sonication. IL+0.5 wt% G dispersions show constant viscosity values from 357K (for IL = [EMIM][DCA]) or from 385K (for IL = [EMIM][TFSI]) to 393K. IL + G dispersions with G > 0.5 wt% show linear viscosity increases with increasing temperature, from 306K (for [EMIM][DCA]+1...

  4. Crystal structure and ionic conduction path of solid electrolytic materials by high temperature neutron diffraction method

    International Nuclear Information System (INIS)

    Yashima, Masatomo; Nomura, Katsuhiro

    2005-01-01

    Research of the distribution of oxide ions and the ionic conduction path of bismuth oxide (Bi 2 O 3 ), cerium oxide (CeO 2 ) and lanthanum gallate ((La 0.8 Sr 0.2 )(Ga 0.8 Mg 0.15 Co 0.05 )O 3-δ ) is stated. The high temperature neutron diffraction method, analytical method such as Rietveld method, crystal structure analysis of ionic conductor and MEM (Maximum- Entropy Method) are explained. The nuclear density distribution of oxide ions in bismuth oxide showed so larger distribution in the direction of and than Bi ions that the oxide ions conducted these direction in the crystal. The nuclear density distribution of oxide ions of cerium oxide indicated larger distribution in the direction of than Ce ions and its tendency was remarkable at high temperature. Accordingly, the oxide ions conducted in the direction of and . The oxide ions distribution in lanthanum gallate compound was larger and complicated than positive ions. The oxide ions conducted to by describing an arc between the two stable positions. The nuclear density on the conduction path increased with increasing temperature. This above result corresponded to increase of oxide ion conductivity in the area. (S.Y.)

  5. A new method for the determination of vaporization enthalpies of ionic liquids at low temperatures.

    Science.gov (United States)

    Verevkin, Sergey P; Zaitsau, Dzmitry H; Emelyanenko, Vladimir N; Heintz, Andreas

    2011-11-10

    A new method for the determination of vaporization enthalpies of extremely low volatile ILs has been developed using a newly constructed quartz crystal microbalance (QCM) vacuum setup. Because of the very high sensitivity of the QCM it has been possible to reduce the average temperature of the vaporization studies by approximately 100 K in comparison to other conventional techniques. The physical basis of the evaluation procedure has been developed and test measurements have been performed with the common ionic liquid 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide [C(2)mim][NTf(2)] extending the range of measuring vaporization enthalpies down to 363 K. The results obtained for [C(2)mim][NTf(2)] have been tested for thermodynamic consistency by comparison with data already available at higher temperatures. Comparison of the temperature-dependent vaporization enthalpy data taken from the literature show only acceptable agreement with the heat capacity difference of -40 J K(-1) mol(-1). The method developed in this work opens also a new way to obtain reliable values of vaporization enthalpies of thermally unstable ionic liquids.

  6. Method for calculating ionic and electronic defect concentrations in y-stabilised zirconia

    Energy Technology Data Exchange (ETDEWEB)

    Poulsen, F W [Risoe National Lab., Materials Research Dept., Roskilde (Denmark)

    1997-10-01

    A numerical (trial and error) method for calculation of concentration of ions, vacancies and ionic and electronic defects in solids (Brouwer-type diagrams) is presented. No approximations or truncations of the set of equations describing the chemistry for the various defect regions are used. Doped zirconia and doped thoria with simultaneous presence of protonic and electronic defects are taken as examples: 7 concentrations as function of oxygen partial pressure and/or water vapour partial pressure are determined. Realistic values for the equilibrium constants for equilibration with oxygen gas and water vapour, as well as for the internal equilibrium between holes and electrons were taken from the literature. The present mathematical method is versatile - it has also been employed by the author to treat more complex systems, such as perovskite structure oxides with over- and under-stoichiometry in oxygen, cation vacancies and simultaneous presence of protons. (au) 6 refs.

  7. Electronic excitation and ionic dissociation of the vanillin molecule: photoionization with flavor

    International Nuclear Information System (INIS)

    Betancourt, A Moreno; De Souza, G G B; Bernini, R B; Coutinho, L H

    2015-01-01

    The electronic properties of vanillin molecule were investigated by different excitation and ionization techniques. The Ionic fragmentation mechanisms were studied using time-of-flight mass spectrometry as a function of the energy of the incident radiation in the valence energy region and the inner and core levels. It was stablished as a general feature that the ruptures related to the oxygen atoms are predominant at all energies. The resonances and ionization potential of the oxygen 1s was also determined by NEXAFS spectra. (paper)

  8. On the critical temperature, normal boiling point, and vapor pressure of ionic liquids.

    Science.gov (United States)

    Rebelo, Luis P N; Canongia Lopes, José N; Esperança, José M S S; Filipe, Eduardo

    2005-04-07

    One-stage, reduced-pressure distillations at moderate temperature of 1-decyl- and 1-dodecyl-3-methylimidazolium bistriflilamide ([Ntf(2)](-)) ionic liquids (ILs) have been performed. These liquid-vapor equilibria can be understood in light of predictions for normal boiling points of ILs. The predictions are based on experimental surface tension and density data, which are used to estimate the critical points of several ILs and their corresponding normal boiling temperatures. In contrast to the situation found for relatively unstable ILs at high-temperature such as those containing [BF(4)](-) or [PF(6)](-) anions, [Ntf(2)](-)-based ILs constitute a promising class in which reliable, accurate vapor pressure measurements can in principle be performed. This property is paramount for assisting in the development and testing of accurate molecular models.

  9. Environmentally friendly room temperature strecker reaction:one-pot synthesis of α-aminonitriles in ionic liquid

    International Nuclear Information System (INIS)

    Mojtahedi, M. M.; Abaee, M.S.; Abbasi, H.

    2006-01-01

    A three component efficient and facile procedure is developed for the synthesis of a-aminonitriles from aromatic-and aliphatic aldehydes, amines, and trimethylsilyl cyanide in 1-butyl-3-methyl-1H-imidazolium perchlorate ([bmim][C1O 4 ]) ionic liquid as the reaction medium at room temperature. Excellent yields are obtained in this one-pot procedure with short reaction times and the ionic liquid medium reused several times in a row

  10. Novel method of room temperature ionic liquid assisted Fe3O4 nanocubes and nanoflakes synthesis

    International Nuclear Information System (INIS)

    Ramalakshmi, M.; Shakkthivel, P.; Sundrarajan, M.; Chen, S.M.

    2013-01-01

    Graphical abstract: - Highlights: • First time [Bmim][TfO] IL is used for the Fe 3 O 4 nanoparticle synthesis. • Novel method tunes Fe 3 O 4 nanocubes and nanoflakes forms influenced by the base and IL. • Fe 3 O 4 oxidized topotactically into γ-Fe 2 O 3 nanoparticles by annealing and base. • Uniform morphology with average size of 33 nm negligible superstructure are formed. • Ms values are characterized by thin layer of γ-Fe 2 O 3 on the nanoparticle surface. - Abstract: For the first time, the nanomagnetite superparamagnetic particles are successfully synthesized by precipitation method using 1-n-butyl-3-methylimidazolium trifluoromethane sulfonate [Bmim][TfO] ionic liquid medium/surfactant. The obtained Fe 3 O 4 particles are nanocubes and nanoflakes and this formation is influenced by the base concentration and anisotropic circumstances produced by the ionic liquid and their size varies from 20 nm to 150 × 300 nm (width × length). The synthesized magnetite nanoparticles are characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy, Field emission scanning electron microscopy (FE-SEM), Transmission electron microscopy (TEM) and Vibrating sample magnetometer (VSM) studies. The results show that the core of the Fe 3 O 4 nanoparticles is surrounded by a thin layer of γ-Fe 2 O 3 by topotactical partial oxidation, which is remarkably proceed with the subsequent calcination. The magnetite nanocubes have high saturation magnetization value and exhibit superparamagnetic hysteresis loop

  11. Dynamical heterogeneities of rotational motion in room temperature ionic liquids evidenced by molecular dynamics simulations

    Science.gov (United States)

    Usui, Kota; Hunger, Johannes; Bonn, Mischa; Sulpizi, Marialore

    2018-05-01

    Room temperature ionic liquids (RTILs) have been shown to exhibit spatial heterogeneity or structural heterogeneity in the sense that they form hydrophobic and ionic domains. Yet studies of the relationship between this structural heterogeneity and the ˜picosecond motion of the molecular constituents remain limited. In order to obtain insight into the time scales relevant to this structural heterogeneity, we perform molecular dynamics simulations of a series of RTILs. To investigate the relationship between the structures, i.e., the presence of hydrophobic and ionic domains, and the dynamics, we gradually increase the size of the hydrophobic part of the cation from ethylammonium nitrate (EAN), via propylammonium nitrate (PAN), to butylammonium nitrate (BAN). The two ends of the organic cation, namely, the charged Nhead-H group and the hydrophobic Ctail-H group, exhibit rotational dynamics on different time scales, evidencing dynamical heterogeneity. The dynamics of the Nhead-H group is slower because of the strong coulombic interaction with the nitrate counter-ionic anions, while the dynamics of the Ctail-H group is faster because of the weaker van der Waals interaction with the surrounding atoms. In particular, the rotation of the Nhead-H group slows down with increasing cationic chain length, while the rotation of the Ctail-H group shows little dependence on the cationic chain length, manifesting that the dynamical heterogeneity is enhanced with a longer cationic chain. The slowdown of the Nhead-H group with increasing cationic chain length is associated with a lower number of nitrate anions near the Nhead-H group, which presumably results in the increase of the energy barrier for the rotation. The sensitivity of the Nhead-H rotation to the number of surrounding nitrate anions, in conjunction with the varying number of nitrate anions, gives rise to a broad distribution of Nhead-H reorientation times. Our results suggest that the asymmetry of the cations and the

  12. Temperature measurement systems in wearable electronics

    Science.gov (United States)

    Walczak, S.; Gołebiowski, J.

    2014-08-01

    The aim of this paper is to present the concept of temperature measurement system, adapted to wearable electronics applications. Temperature is one of the most commonly monitored factor in smart textiles, especially in sportswear, medical and rescue products. Depending on the application, measured temperature could be used as an initial value of alert, heating, lifesaving or analysis system. The concept of the temperature measurement multi-point system, which consists of flexible screen-printed resistive sensors, placed on the T-shirt connected with the central unit and the power supply is elaborated in the paper.

  13. Molecular dynamics study of room temperature ionic liquids with water at mica surface

    Directory of Open Access Journals (Sweden)

    Huanhuan Zhang

    2018-04-01

    Full Text Available Water in room temperature ionic liquids (RTILs could impose significant effects on their interfacial properties at a charged surface. Although the interfaces between RTILs and mica surfaces exhibit rich microstructure, the influence of water content on such interfaces is little understood, in particular, considering the fact that RTILs are always associated with water due to their hygroscopicity. In this work, we studied how different types of RTILs and different amounts of water molecules affect the RTIL-mica interfaces, especially the water distribution at mica surfaces, using molecular dynamics (MD simulation. MD results showed that (1 there is more water and a thicker water layer adsorbed on the mica surface as the water content increases, and correspondingly the average location of K+ ions is farther from mica surface; (2 more water accumulated at the interface with the hydrophobic [Emim][TFSI] than in case of the hydrophilic [Emim][BF4] due to the respective RTIL hydrophobicity and ion size. A similar trend was also observed in the hydrogen bonds formed between water molecules. Moreover, the 2D number density map of adsorbed water revealed that the high-density areas of water seem to be related to K+ ions and silicon/aluminum atoms on mica surface. These results are of great importance to understand the effects of hydrophobicity/hydrophicility of RTIL and water on the interfacial microstructure at electrified surfaces. Keywords: Room temperature ionic liquids, Hydrophobicity/hydrophicility, Water content, Electrical double layer, Mica surface

  14. CL 14: Solvation structure and dynamics of room temperature ionic liquids

    International Nuclear Information System (INIS)

    Musat, Raluca M.; Polyansky, Dmitriy; Crowell, Robert A.; Thomas, Marie; Wishart, James F.; Takahashi, Kenji; Katsumura, Yosuke

    2010-01-01

    Room temperature ionic liquids (RTILs) have emerged as a new class of solvents that, due to their unique properties (e.g., low volatility, large electrochemical window, high conductivity, etc.), have several potential applications. Among these are their possible use in nuclear fuel reprocessing, dye sensitized solar cells, and CO 2 sequestration. The properties of a given class of RTILs depend strongly on the choice of the counter anion. In this contribution we present new results using both static and time-resolved EXAFS (ca. 1 ns resolution) and time resolved optical absorption spectroscopy on a series of bromide containing imidazolium salts. The static results provide detailed information of the solvation shell of the bromide ion while the time-resolved data shed light on the nature and chemical behavior of the lowest lying charge transfer band, the physical motion of the bromine atom and its conversion to di-bromide. The photochemistry of the charge transfer (CT) band of the room temperature ionic liquid 1-hexyl-3-methylimidazolium bromide is investigated using ultrafast transient absorption spectroscopy (TA) in the near-IR and steady state UV absorption. Irradiation of the CT band at 266 nm results in the steady state production of di-bromide which absorbs strongly at 266 nm. It is shown that this photoproduct, which is apparently very stable, adversely affects ultrafast transient absorption measurements. Flowing and simultaneously translating the sample mitigates this effect and reveals new transient species and dynamics within the detection window of 850 nm to 1250 nm. (authors)

  15. Engineering Mixed Ionic Electronic Conduction in La 0.8 Sr 0.2 MnO 3+ δ Nanostructures through Fast Grain Boundary Oxygen Diffusivity

    KAUST Repository

    Saranya, Aruppukottai M.; Pla, Dolors; Morata, Alex; Cavallaro, Andrea; Canales-Vá zquez, Jesú s; Kilner, John A.; Burriel, Mó nica; Tarancó n, Albert

    2015-01-01

    to implement in nanostructures. Here, an artificial mixed ionic electronic conducting oxide is fabricated by grain boundary (GB) engineering thin films of La0.8Sr0.2MnO3+δ. This electronic conductor is converted into a good mixed ionic electronic conductor

  16. Electron Bernstein wave electron temperature profile diagnostic (invited)

    International Nuclear Information System (INIS)

    Taylor, G.; Efthimion, P.; Jones, B.; Munsat, T.; Spaleta, J.; Hosea, J.; Kaita, R.; Majeski, R.; Menard, J.

    2001-01-01

    Electron cyclotron emission (ECE) has been employed as a standard electron temperature profile diagnostic on many tokamaks and stellarators, but most magnetically confined plasma devices cannot take advantage of standard ECE diagnostics to measure temperature. They are either ''overdense,'' operating at high density relative to the magnetic field (e.g., ω pe >>Omega ce in a spherical torus) or they have insufficient density and temperature to reach the blackbody condition (τ>2). Electron Bernstein waves (EBWs) are electrostatic waves that can propagate in overdense plasmas and have a high optical thickness at the electron cyclotron resonance layers as a result of their large k perp . In this article we report on measurements of EBW emission on the CDX-U spherical torus, where B 0 ∼2kG, e >∼10 13 cm -3 and T e ∼10--200eV. Results are presented for electromagnetic measurements of EBW emission, mode converted near the plasma edge. The EBW emission was absolutely calibrated and compared to the electron temperature profile measured by a multipoint Thomson scattering diagnostic. Depending on the plasma conditions, the mode-converted EBW radiation temperature was found to be ≤T e and the emission source was determined to be radially localized at the electron cyclotron resonance layer. A Langmuir triple probe and a 140 GHz interferometer were employed to measure changes in the edge density profile in the vicinity of the upper hybrid resonance where the mode conversion of the EBWs is expected to occur. Initial results suggest EBW emission and EBW heating are viable concepts for plasmas where ω pe >>Omega ce

  17. Effect of fluid velocity, temperature, and concentration of non-ionic surfactants on drag reduction

    International Nuclear Information System (INIS)

    Cho, Sung-Hwan; Tae, Choon-Seob; Zaheeruddin, M.

    2007-01-01

    The drag reduction (DR) and heat transfer efficiency reduction (ER) of non-ionic surfactant as a function of fluid velocity, temperature, and surfactant concentration were investigated. Several types of new surfactants, which contain amine-oxide and betaine, were developed. An experimental apparatus consisting of two temperature controlled water storage tanks, pumps, test specimen pipe and the piping network, two flow meters, two pressure gauges, a heat exchanger, and data logging system was built. From the experimental results, it was concluded that existing alkyl ammonium surfactant (CTAC; cethyl trimethyl ammonium chloride) had DR of 0.6-0.8 at 1000-2000 ppm concentration with fluid temperature ranging between 50 and 60 o C. However, the DR was very low when the fluid temperature was 70-80 o C. The new amine oxide and betaine surfactant (SAOB; stearyl amine oxide + betaine) had lower DR at fluid temperatures ranging between 50 and 60 o C compared with CTAC. However, with fluid temperature ranging between 70 and 80 o C the DR was 0.6-0.8 when the concentration level was between 1000 and 2000 ppm

  18. Direct electron transfer of hemoglobin in a CdS nanorods and Nafion composite film on carbon ionic liquid electrode

    International Nuclear Information System (INIS)

    Sun Wei; Wang Dandan; Li Guicun; Zhai Ziqin; Zhao Ruijun; Jiao Kui

    2008-01-01

    In this paper the direct electron transfer of hemoglobin (Hb) was carefully investigated by using a room temperature ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate (BMIMPF 6 ) modified carbon paste electrode (CILE) as the basal working electrode. Hb was immobilized on the surface of CILE with the nanocomposite film composed of Nafion and CdS nanorods by a step-by-step method. UV-vis and FT-IR spectra showed that Hb in the composite film remained its native structure. The direct electrochemical behaviors of Hb in the composite film were further studied in a pH 7.0 phosphate buffer solution (PBS). A pair of well-defined and quasi-reversible cyclic voltammetric peaks of Hb was obtained with the formal potential (E 0 ') at -0.295 V (vs. SCE), which was the characteristic of heme Fe(III)/Fe(II) redox couples. The direct electrochemistry of Hb was achieved on the modified electrode and the apparent heterogeneous electron transfer rate constant (k s ) was calculated to be 0.291 s -1 . The formal potentials of Hb Fe(III)/Fe(II) couple shifted negatively with the increase of buffer pH and a slope value of -45.1 mV/pH was got, which indicated that one electron transfer accompanied with one proton transportation. The fabricated Hb sensor showed good electrocatalytic manner to the reduction of trichloroacetic acid (TCA)

  19. Electrochemically oxidized electronic and ionic conducting nanostructured block copolymers for lithium battery electrodes.

    Science.gov (United States)

    Patel, Shrayesh N; Javier, Anna E; Balsara, Nitash P

    2013-07-23

    Block copolymers that can simultaneously conduct electronic and ionic charges on the nanometer length scale can serve as innovative conductive binder material for solid-state battery electrodes. The purpose of this work is to study the electronic charge transport of poly(3-hexylthiophene)-b-poly(ethylene oxide) (P3HT-PEO) copolymers electrochemically oxidized with lithium bis(trifluoromethanesulfonyl) imide (LiTFSI) salt in the context of a lithium battery charge/discharge cycle. We use a solid-state three-terminal electrochemical cell that enables simultaneous conductivity measurements and control over electrochemical doping of P3HT. At low oxidation levels (ratio of moles of electrons removed to moles of 3-hexylthiophene moieties in the electrode), the electronic conductivity (σe,ox) increases from 10(-7) S/cm to 10(-4) S/cm. At high oxidation levels, σe,ox approaches 10(-2) S/cm. When P3HT-PEO is used as a conductive binder in a positive electrode with LiFePO4 active material, P3HT is electrochemically active within the voltage window of a charge/discharge cycle. The electronic conductivity of the P3HT-PEO binder is in the 10(-4) to 10(-2) S/cm range over most of the potential window of the charge/discharge cycle. This allows for efficient electronic conduction, and observed charge/discharge capacities approach the theoretical limit of LiFePO4. However, at the end of the discharge cycle, the electronic conductivity decreases sharply to 10(-7) S/cm, which means the "conductive" binder is now electronically insulating. The ability of our conductive binder to switch between electronically conducting and insulating states in the positive electrode provides an unprecedented route for automatic overdischarge protection in rechargeable batteries.

  20. Unusual mechanism for the short-range electron transfer within gold-alkanethiol-ionic-liquid films of subnanometer thickness

    International Nuclear Information System (INIS)

    Khoshtariya, Dimitri E.; Dolidze, Tina D.; Eldik, Rudi van

    2009-01-01

    Exploiting nanoscopically tunable composite gold-alkanethiol-ionic-liquid/ferrocene self-assembled systems with tunable electron transfer distance, we discovered in the case of thinner alkanethiol films a thermally activated electron transfer pattern totally controlled by the viscosity-related slow relaxation mode(s) of the ionic liquid acting as the reactant's fluctuating environment. This pattern manifested through the activation enthalpy and volume parameters that are identical to those for viscous flow was explained in terms of the extreme adiabatic mechanism with a vanishing Marcus barrier (via the exponential Franck-Condon-like term approaching unity).

  1. Electrospun polymer membrane activated with room temperature ionic liquid: Novel polymer electrolytes for lithium batteries

    Science.gov (United States)

    Cheruvally, Gouri; Kim, Jae-Kwang; Choi, Jae-Won; Ahn, Jou-Hyeon; Shin, Yong-Jo; Manuel, James; Raghavan, Prasanth; Kim, Ki-Won; Ahn, Hyo-Jun; Choi, Doo Seong; Song, Choong Eui

    A new class of polymer electrolytes (PEs) based on an electrospun polymer membrane incorporating a room-temperature ionic liquid (RTIL) has been prepared and evaluated for suitability in lithium cells. The electrospun poly(vinylidene fluoride- co-hexafluoropropylene) P(VdF-HFP) membrane is activated with a 0.5 M solution of LiTFSI in 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide (BMITFSI) or a 0.5 M solution of LiBF 4 in 1-butyl-3-methylimidazolium tetrafluoroborate (BMIBF 4). The resulting PEs have an ionic conductivity of 2.3 × 10 -3 S cm -1 at 25 °C and anodic stability at >4.5 V versus Li +/Li, making them suitable for practical applications in lithium cells. A Li/LiFePO 4 cell with a PE based on BMITFSI delivers high discharge capacities when evaluated at 25 °C at the 0.1 C rate (149 mAh g -1) and the 0.5 C rate (132 mAh g -1). A very stable cycle performance is also exhibited at these low current densities. The properties decrease at the higher, 1 C rate, when operated at 25 °C. Nevertheless, improved properties are obtained at a moderately elevated temperature of operation, i.e. 40 °C. This is attributed to enhanced conductivity of the electrolyte and faster reaction kinetics at higher temperatures. At 40 °C, a reversible capacity of 140 mAh g -1 is obtained at the 1 C rate.

  2. Room temperature ionic liquids interacting with bio-molecules: an overview of experimental and computational studies

    Science.gov (United States)

    Benedetto, Antonio; Ballone, Pietro

    2016-03-01

    We briefly review experimental and computational studies of room temperature ionic liquids (RTILs) interacting with important classes of biomolecules, including phospholipids, peptides and proteins, nucleic acids and carbohydrates. Most of these studies have been driven by the interest for RTILs applications as solvents. Thus, available experimental data cover primarily thermodynamic properties such as the reciprocal solubility of RTILs and bio-molecules, as well as phase boundaries. Less extensive data are also available on transport properties such as diffusion and viscosity of homogeneous binary (RTILs/biomolecules) and ternary (RTIL/biomolecules/water) solutions. Most of the structural information at the atomistic level, of interest especially for biochemical, pharmaceutical and nanotechnology applications, has been made available by molecular dynamics simulations. Major exceptions to this statement are represented by the results from NMR and circular dichroism spectroscopy, by selected neutron and X-ray scattering data, and by recent neutron reflectometry measurements on lipid bilayers on surfaces, hydrated by water-RTIL solutions. A final section of our paper summarizes new developments in the field of RTILs based on amino acids, that combine in themselves the two main aspects of our discussion, i.e. ionic liquids and bio-molecules.

  3. Determination of the physical properties of room temperature ionic liquids using a Love wave device.

    Science.gov (United States)

    Ouali, F Fouzia; Doy, Nicola; McHale, Glen; Hardacre, Christopher; Ge, Rile; Allen, Ray W K; MacInnes, Jordan M; Newton, Michael I

    2011-09-01

    In this work, we have shown that a 100 MHz Love wave device can be used to determine whether room temperature ionic liquids (RTILs) are Newtonian fluids and have developed a technique that allows the determination of the density-viscosity product, ρη, of a Newtonian RTIL. In addition, a test for a Newtonian response was established by relating the phase change to insertion loss change. Five concentrations of a water-miscible RTIL and seven pure RTILs were measured. The changes in phase and insertion loss were found to vary linearly with the square root of the density-viscosity product for values up to (ρη)(1/2) ~ 10 kg m(-2) s(-1/2). The square root of the density-viscosity product was deduced from the changes in either phase or insertion loss using glycerol as a calibration liquid. In both cases, the deduced values of ρη agree well with those measured using viscosity and density meters. Miniaturization of the device, beyond that achievable with the lower-frequency quartz crystal microbalance approach, to measure smaller volumes is possible. The ability to fabricate Love wave and other surface acoustic wave sensors using planar metallization technologies gives potential for future integration into lab-on-a-chip analytical systems for characterizing ionic liquids.

  4. Temperature dependent electronic conduction in semiconductors

    International Nuclear Information System (INIS)

    Roberts, G.G.; Munn, R.W.

    1980-01-01

    This review describes the temperature dependence of bulk-controlled electronic currents in semiconductors. The scope of the article is wide in that it contrasts conduction mechanisms in inorganic and organic solids and also single crystal and disordered semiconductors. In many experimental situations it is the metal-semiconductor contact or the interface between two dissimilar semiconductors that governs the temperature dependence of the conductivity. However, in order to keep the length of the review within reasonable bounds, these topics have been largely avoided and emphasis is therefore placed on bulk-limited currents. A central feature of electronic conduction in semiconductors is the concentrations of mobile electrons and holes that contribute to the conductivity. Various statistical approaches may be used to calculate these densities which are normally strongly temperature dependent. Section 1 emphasizes the relationship between the position of the Fermi level, the distribution of quantum states, the total number of electrons available and the absolute temperature of the system. The inclusion of experimental data for several materials is designed to assist the experimentalist in his interpretation of activation energy curves. Sections 2 and 3 refer to electronic conduction in disordered solids and molecular crystals, respectively. In these cases alternative approaches to the conventional band theory approach must be considered. For example, the velocities of the charge carriers are usually substantially lower than those in conventional inorganic single crystal semiconductors, thus introducing the possibility of an activated mobility. Some general electronic properties of these materials are given in the introduction to each of these sections and these help to set the conduction mechanisms in context. (orig.)

  5. Room-temperature solid phase ionic liquid (RTSPIL) coated Ω-transaminases: Development and application in organic solvents

    DEFF Research Database (Denmark)

    Grabner, B.; Nazario, M. A.; Gundersen, M. T.

    2018-01-01

    ω-Transaminases ATA-40, ATA-47 and ATA-82P were coated with room-temperature solid phase ionic liquids (RTSPILs) by means of three methods, melt coating, precipitation coating, and co‐lyophilization, and showed increased stability in all of the five tested organic solvents. Co‐lyophilization and ......ω-Transaminases ATA-40, ATA-47 and ATA-82P were coated with room-temperature solid phase ionic liquids (RTSPILs) by means of three methods, melt coating, precipitation coating, and co‐lyophilization, and showed increased stability in all of the five tested organic solvents. Co...

  6. Substitution of conventional high-temperature syntheses of inorganic compounds by near-room-temperature syntheses in ionic liquids

    KAUST Repository

    Groh, Matthias Friedrich

    2013-01-01

    The high-temperature syntheses of the low-valent halogenides P2I4, Te2Br, α-Te4I4, Te4(Al2Cl7)2, Te4(Bi6Cl20), Te8(Bi4Cl14),Bi8(AlCl4)2, Bi6Cl7,and Bi6Br7, as well as of WSCl4 andWOCl4 have been replaced by resource-efficient low-temperature syntheses in room temperature ionic liquids (RTILs). The simple one-pot syntheses generally do not require elaborate equipment such as twozone furnaces or evacuated silica ampoules. Compared to the published conventional approaches, reduction of reaction time (up to 80%) and temperature (up to 500 K) and, simultaneously, an increase in yield were achieved. In the majority of cases, the solid products were phase-pure. X-Ray diffraction on single crystals (redetermination of 11 crystal structures) has demonstrated that the quality of the crystals from RTILs is comparable to that of products obtained by chemical transport reactions. © 2013 Verlag der Zeitschrift für Naturforschung, Tübingen.

  7. Ultramicroelectrode voltammetry and scanning electrochemical microscopy in room-temperature ionic liquid electrolytes.

    Science.gov (United States)

    Walsh, Darren A; Lovelock, Kevin R J; Licence, Peter

    2010-11-01

    The high viscosity and unusual properties of room temperature ionic liquids (RTILs) present a number of challenges when performing steady-state voltammetry and scanning electrochemical microscopy in RTILs. These include difficulties in recording steady-state currents at ultramicroelectrode surfaces due to low diffusion coefficients of redox species and problems associated with unequal diffusion coefficients of oxidised and reduced species in RTILs. In this tutorial review, we highlight the recent progress in the use of RTILs as electrolytes for ultramicroelectrode voltammetry and SECM. We describe the basic principles of ultramicroelectrode voltammetry and SECM and, using examples from the recent literature, we discuss the conditions that must be met to perform steady-state voltammetry and SECM measurements in RTILs. Finally, we briefly discuss the electrochemical insights that can be obtained from such measurements.

  8. Miniaturized Planar Room Temperature Ionic Liquid Electrochemical Gas Sensor for Rapid Multiple Gas Pollutants Monitoring.

    Science.gov (United States)

    Wan, Hao; Yin, Heyu; Lin, Lu; Zeng, Xiangqun; Mason, Andrew J

    2018-02-01

    The growing impact of airborne pollutants and explosive gases on human health and occupational safety has escalated the demand of sensors to monitor hazardous gases. This paper presents a new miniaturized planar electrochemical gas sensor for rapid measurement of multiple gaseous hazards. The gas sensor features a porous polytetrafluoroethylene substrate that enables fast gas diffusion and room temperature ionic liquid as the electrolyte. Metal sputtering was utilized for platinum electrodes fabrication to enhance adhesion between the electrodes and the substrate. Together with carefully selected electrochemical methods, the miniaturized gas sensor is capable of measuring multiple gases including oxygen, methane, ozone and sulfur dioxide that are important to human health and safety. Compared to its manually-assembled Clark-cell predecessor, this sensor provides better sensitivity, linearity and repeatability, as validated for oxygen monitoring. With solid performance, fast response and miniaturized size, this sensor is promising for deployment in wearable devices for real-time point-of-exposure gas pollutant monitoring.

  9. Room temperature ionic liquids for actinide extraction: a 'green' approach?

    International Nuclear Information System (INIS)

    Mohapatra, P.K.

    2013-01-01

    Extraction of actinides is one of the key issues in the remediation of high level radioactive wastes emanating from the back end of the nuclear fuel cycle. Effective actinide extraction makes the waste benign and ready for disposal as vitrified waste blocks in deep geological repositories. However, conventional solvent extraction methods, though being routinely used for actinide separations, have several disadvantages, which include large VOC (volatile organic compounds) inventory and generation of huge volumes of secondary wastes. Growing concern for the environment has led to the increasing interest in room temperature ionic liquids (RTIL) as an alternative to molecular diluents in myriad applications including synthesis, catalysis, separation and electrochemistry. Out of these, application of RTILs to separation science has increased enormously as can be seen from the rapid rise in the number of publications in this area in the last decade, due to their unique characteristics of high thermal stability and low volatility

  10. Electrodeposition at room temperature of amorphous silicon and germanium nanowires in ionic liquid

    Energy Technology Data Exchange (ETDEWEB)

    Martineau, F; Namur, K; Mallet, J; Delavoie, F; Troyon, M; Molinari, M [Laboratoire de Microscopies et d' Etude de Nanostructures (LMEN EA3799), Universite de Reims Champagne Ardennes (URCA), Reims Cedex 2 (France); Endres, F, E-mail: michael.molinari@univ-reims.fr [Institute of Particle Technology, Chair of Interface Processes, Clausthal University of Technology, D-36678 Clausthal-Zellerfeld (Germany)

    2009-11-15

    The electrodeposition at room temperature of silicon and germanium nanowires from the air- and water-stable ionic liquid 1-butyl-1-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide (P{sub 1,4}) containing SiCl{sub 4} as Si source or GeCl{sub 4} as Ge source is investigated by cyclic voltammetry. By using nanoporous polycarbonate membranes as templates, it is possible to reproducibly grow pure silicon and germanium nanowires of different diameters. The nanowires are composed of pure amorphous silicon or germanium. The nanowires have homogeneous cylindrical shape with a roughness of a few nanometres on the wire surfaces. The nanowires' diameters and lengths well match with the initial membrane characteristics. Preliminary photoluminescence experiments exhibit strong emission in the near infrared for the amorphous silicon nanowires.

  11. Surface tension anomalies in room temperature ionic liquids-acetone solutions

    Science.gov (United States)

    Abe, Hiroshi; Murata, Keisuke; Kiyokawa, Shota; Yoshimura, Yukihiro

    2018-05-01

    Surface tension anomalies were observed in room temperature ionic liquid (RTIL)-acetone solutions. The RTILs are 1-alkyl-3-methylimidazorium iodide with [Cnmim][I] in a [Cnmim][I]-x mol% acetone. The maximum value of the surface tension appeared at 40 mol% acetone, although density decreased monotonically with an increase in acetone concentration. A small alkyl chain length effect of the Cnmim+ cations was observed in the surface tension. By the Gibbs adsorption isotherm, it was found that I- anion-mediated surface structure became dominant above 40 mol%. In the different [Cnmim][TFSI]-acetone mixtures, normal decay of the surface tension was observed on the acetone concentration scale, where TFSI- is bis(trifluoromethanesulfonyl)imide.

  12. Properties for binary mixtures of (acetamide + KSCN) eutectic ionic liquid with ethanol at several temperatures

    International Nuclear Information System (INIS)

    Liu, Baoyou; Liu, Yaru

    2016-01-01

    Graphical abstract: Viscosity deviation (Δη) against mole fraction of ethanol for [ethanol(1) + [(acetamide + KSCN)](2)] mixtures at several temperatures. The solid lines represent the corresponding correlation by the Redlich–Kister equation. - Highlights: • Density, viscosity and conductivity of (acetamide + KSCN) ethanol solution were measured. • V"E and Δη were calculated from the measured density and viscosity respectively. • V"E and Δη were both well fitted by a third order Redlich–Kister equation. • The conductivity was described by a Castell–Amis equation. - Abstract: Density, viscosity and conductivity were determined for the binary mixture of (acetamide + KSCN) eutectic ionic liquid with ethanol at T = (298.15, 303.15, 308.15, 313.15, 318.15) K and atmospheric pressure. The density, viscosity values decrease with the increase of temperature while the conductivity values increase over the whole concentration range. The density and viscosity values decrease monotonically with the increase of the mole content of ethanol. From the experimental values, excess molar volumes V"E and viscosity deviations Δη for the binary mixture were calculated and V"E and Δη were both well fitted by a third order Redlich–Kister equation. With the increase mole fraction of ethanol, the conductivity values of the mixture increase gradually first and then decrease dramatically, and the highest conductivity values appear at 0.8562 mol fraction of ethanol. The relationship between the conductivity and the mole fraction of ethanol can be well described by a Castell–Amis equation. The interactions with ethanol molecular and ions of (acetamide + KSCN) ionic liquid were discussed by FTIR spectra.

  13. Electron temperature measurement in Z-pinch

    International Nuclear Information System (INIS)

    Gerusov, A.V.; Orlov, M.M.; Terent'ev, A.R.; Khrabrov, V.A.

    1987-01-01

    Measurement of temperature of emitting plasma sheath in noncylindrical Z-pinch in neon at the stage of convergence to the axis, based on comparing the intensity of spectral lines belonging to Ne1, Ne2, is performed. Line intensity relation dependence was determined using calculations according to emitting-collision model. Spectra were recorded by electron-optical converter and relative intensity was determined by subsequent photometry of photolayer. Cylindric symmetrical MHD-calculations during which temperature and the observed line intensity relation were determined, are conducted

  14. Measurement and modelling of the defect chemistry and transport properties of ceramic oxide mixed ionic and electronic conductors

    DEFF Research Database (Denmark)

    Dalslet, Bjarke Thomas

    2008-01-01

    The subject of this thesis is ceramic mixed ionic and electronic conductors (MIECs). MIECs have potential uses, such as solid oxygen permeation membranes, as catalysts, and as components in fuel cells. The MIECs examined in this thesis are all oxide ion conducting materials. This thesis describes...

  15. Cryo-transmission electron microscopy of Ag nanoparticles grown on an ionic liquid substrate

    KAUST Repository

    Anjum, Dalaver H.

    2010-07-01

    We report a novel method of growing silver nanostructures by cathodic sputtering onto an ionic liquid (IL) and our visualization by transmission cryo-electron microscopy to avoid beam-induced motion of the nanoparticles. By freezing the IL suspension and controlling electron dose, we can assess properties of particle size, morphology, crystallinity, and aggregation in situ and at high detail. We observed round silver nanoparticles with a well-defined diameter of 7.0 ± 1.5 nm that are faceted with crystalline cubic structures and ∼80% of the particles have multiply twinned faults. We also applied cryo-electron tomography to investigate the structure of the nanoparticles and to directly visualize the IL wetting around them. In addition to particles, we observed nanorods that appear to have assembled from individual nanoparticles. Reexamination of the samples after 4-5 days from initial preparation showed significant changes in morphology, and potential mechanisms for this are discussed. © 2010 Materials Research Society.

  16. Fluorescent probe studies of polarity and solvation within room temperature ionic liquids: a review.

    Science.gov (United States)

    Pandey, Shubha; Baker, Sheila N; Pandey, Siddharth; Baker, Gary A

    2012-09-01

    Ionic liquids display an array of useful and sometimes unconventional, solvent features and have attracted considerable interest in the field of green chemistry for the potential they hold to significantly reduce environmental emissions. Some of these points have a bearing on the chemical reactivity of these systems and have also generated interest in the physical and theoretical aspects of solvation in ionic liquids. This review presents an introduction to the field of ionic liquids, followed by discussion of investigations into the solvation properties of neat ionic liquids or mixed systems including ionic liquids as a major or minor component. The ionic liquid based multicomponent systems discussed are composed of other solvents, other ionic liquids, carbon dioxide, surfactants or surfactant solutions. Although we clearly focus on fluorescence spectroscopy as a tool to illuminate ionic liquid systems, the issues discussed herein are of general relevance to discussions of polarity and solvent effects in ionic liquids. Transient solvation measurements carried out by means of time-resolved fluorescence measurements are particularly powerful for their ability to parameterize the kinetics of the solvation process in ionic liquids and are discussed as well.

  17. Cyclic voltammetry of ion transfer across a room temperature ionic liquid membrane supported by a microporous filter

    Czech Academy of Sciences Publication Activity Database

    Langmaier, Jan; Samec, Zdeněk

    2007-01-01

    Roč. 9, č. 9 (2007), s. 2633-2638 ISSN 1388-2481 R&D Projects: GA AV ČR IAA400400704 Institutional research plan: CEZ:AV0Z40400503 Keywords : room-temperature ionic membrane * cyclic voltammetry * standard Gibbs energy of ion transfer * linear Gibbs energy relationship Subject RIV: CG - Electrochemistry Impact factor: 4.186, year: 2007

  18. On the viscosity of two 1-butyl-1-methylpyrrolidinium ionic liquids: effect of the temperature and pressure

    DEFF Research Database (Denmark)

    Gaciño, Félix M.; Comuñas, María J.P.; Regueira Muñiz, Teresa

    2015-01-01

    to measure viscosities as a function of temperature and pressure fortwo ionic liquids (ILs): 1-butyl-1-methylpyrrolidinium tris(pentafluoroethyl)trifluorophosphateand 1-butyl-1-methylpyrrolidinium trifluoromethanesulfonate.Besides, we have measured the flow curves at pressures up to 75 MPa and shear rates up...

  19. Effect of temperature on mixing thermodynamics of a new ionic liquid: {2-Hydroxy ethylammonium formate (2-HEAF) + short hydroxylic solvents}

    International Nuclear Information System (INIS)

    Iglesias, M.; Torres, A.; Gonzalez-Olmos, R.; Salvatierra, D.

    2008-01-01

    Density and ultrasonic velocity of the mixtures of the new ionic liquid 2-hydroxy ethylammonium formate (2-HEAF) and short hydroxylic solvents (water, methanol, and ethanol) have been measured at the range of temperature (288.15 to 323.15) K and atmospheric pressure. The corresponding apparent molar volume and the apparent molar isentropic compressibility values have been evaluated from the experimental data and fitted to a temperature dependent Redlich-Mayer equation. From these correlations, the limiting infinite dilution values of the apparent magnitudes have also been computed. Derived properties such as isobaric expansibility and isothermal coefficient of pressure excess molar enthalpy were computed due to their importance in the study of specific molecular interactions. The new experimental data were used to test the capability of prediction of the modified Heller temperature dependent equation (MHE) and collision factor theory (CFT). The obtained results indicate that ionic liquid interactions in water are weaker than in the studied alcoholic solutions. An intersection point in isotherms of isentropic compressibility was observed for aqueous solutions which may be an indication of the clathrate structural interactions at high solvent composition. The observed inverse dependence on temperature for aqueous or alcoholic mixtures points out the special trend of packing of this ionic liquid into hydroxylic solvents and its strong dependence on steric hindrance of aliphatic residues. As previously observed, the increase in van der Waals forces due to the presence of long alkyl chain (into ionic liquid and alcohols) leads to higher interactions on mixing

  20. Multi-podant diglycolamides and room temperature ionic liquid impregnated resins: an excellent combination for extraction chromatography of actinides

    NARCIS (Netherlands)

    Gujar, R.B.; Ansari, S.A.; Verboom, Willem; Mohapatra, P.K.

    2016-01-01

    Extraction chromatography resins, prepared by impregnating two multi-podant diglycolamide ligands, viz. diglycolamide-functionalized calix[4]arene (C4DGA) and tripodal diglycolamide (T-DGA) dissolved in the room temperature ionic liquid 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)amide

  1. Extraction of plutonium(IV) by diglycolamide extractants in room temperature ionic liquids

    Energy Technology Data Exchange (ETDEWEB)

    Prabhu, Dattaprasad R.; Raut, Dhaval R.; Murali, Mallekav S.; Mohapatra, Prasanta K. [Bhabha Atomic Research Centre, Mumbai (India). Radiochemistry Div.

    2017-06-01

    Extraction of Pu(IV) was investigated using solutions of two diglycolamide extractants viz., N,N,N{sup '},N{sup '}-tetra-n-octyldiglycolamide (TODGA) and its branched homolog, N,N,N{sup '},N{sup '}-tetra(2-ethylhexyl) diglycolamide (T2EHDGA), dissolved in two imidazolium based room temperature ionic liquids viz., 1-butyl-3-methylimidazolium bis(trifluoromethanesulphonyl) imide ([C{sub 4}mim][NTf{sub 2}]) and 1-octyl-3-methylimidazolium bis(trifluoromethanesulphonyl) imide ([C{sub 8}mim][NTf{sub 2}]) from aqueous nitric acid medium. The extraction kinetics was found to be extremely slow which is reported for the first time for analogous extraction systems and took as long as 30 h to attain equilibrium D{sub Pu} values. In general, TODGA based solvents showed better extraction of Pu(IV) than the T2EHDGA based solvents, one order of magnitude higher, and though both the ionic liquids ultimately yielded comparable D{sub Pu} values, attainment of equilibrium was slower with [C{sub 4}mim][NTf{sub 2}]. The extracted species conformed to 1:1 for TODGA in both the ionic liquids while a mixture of 1:1 and 1:2 species was observed for T2EHDGA at 1 M HNO{sub 3} which changed to 1:1 species at 4 M HNO{sub 3}. The extracted species is proposed to be (Pu(L){sub x}{sup 4+}){sub IL} (where, L is the extractant and x=1 or 2) at lower acidities suggesting a cation exchange mechanism which changes over to (Pu(NO{sub 3}){sub 4} .L){sub IL} at 4 M HNO{sub 3} conforming to a solvation mechanism for all the systems except for T2EHDGA-[C{sub 8}mim][NTf{sub 2}]. UV-VIS spectroscopic studies were carried out to throw light on the nature of the extracted species.

  2. Solvation of a Small Metal-Binding Peptide in Room-Temperature Ionic Liquids

    Energy Technology Data Exchange (ETDEWEB)

    Shim, Youngseon; Jung, Younjoon [Seoul National Univ., Seoul (Korea, Republic of); Kim, Hyung J. [Carnegie Mellon Univ., Pittsburgh (United States)

    2012-11-15

    Structural properties of a small hexapeptide molecule modeled after metal-binding siderochrome immersed in a room-temperature ionic liquid (RTIL) are studied via molecular dynamics simulations. We consider two different RTILs, each of which is made up of the same cationic species, 1-butyl-3-methylimidazolium (BMI{sup +}), but different anions, hexafluorophosphate (PF{sub 6}{sup -}) and chloride (Cl{sup -}). We investigate how anionic properties such as hydrophobicity/hydrophilicity or hydrogen bonding capability affect the stabilization of the peptide in RTILs. To examine the effect of peptide-RTIL electrostatic interactions on solvation, we also consider a hypothetical solvent BMI{sup 0}Cl{sup 0}, a non-ionic counter-part of BMI{sup +}Cl{sup -}. For reference, we investigate solvation structures in common polar solvents, water and dimethylsulfoxide (DMSO). Comparison of BMI{sup +}Cl{sup -} and BMI{sup 0}Cl{sup 0} shows that electrostatic interactions of the peptide and RTIL play a significant role in the conformational fluctuation of the peptide. For example, strong electrostatic interactions between the two favor an extended conformation of the peptide by reducing its structural fluctuations. The hydrophobicity/hydrophilicity of RTIL anions also exerts a notable influence; specifically, structural fluctuations of the peptide become reduced in more hydrophilic BMI{sup +}Cl{sup -}, compared with those in more hydrophobic BMI{sup +}PF{sub 6}{sup -}. This is ascribed to the good hydrogen-bond accepting power of chloride anions, which enables them to bind strongly to hydroxyl groups of the peptide and to stabilize its structure. Transport properties of the peptide are examined briefly. Translations of the peptide significantly slow down in highly viscous RTILs.

  3. Changes of electrochemical properties of polypyrrole when synthesized in a room-temperature ionic liquid

    Energy Technology Data Exchange (ETDEWEB)

    Dalmolin, Carla, E-mail: carla.dalmolin@udesc.br; Biaggio, Sonia R.; Bocchi, Nerilso; Rocha-Filho, Romeu C.

    2014-09-15

    The room-temperature ionic liquid (RTIL) 1-butyl-3-methylimidazolium tetrafluoroborate, BMIM BF{sub 4}, was employed as electrolyte in the electrosynthesis of thin polypyrrole (PPy) films on a Pt substrate, and the resulting PPy electrodes were electrochemically characterized. Electrochemical impedance spectroscopy (EIS) was used to comparatively investigate the electric behavior of PPy produced in the RTIL and the one produced in a traditional acetonitrile/lithium salt system, and charge–discharge curves in the range 2.0–4.0 V (vs. Li/Li{sup +}) were obtained in a 1.0 M LiBF{sub 4} propylene carbonate solution. Although a reduction of the specific capacity for the PPy obtained in the RTIL was observed, compared to that of the PPy film synthesized in the acetonitrilic electrolyte, its chronopotentiometric profile presented a plateau in the 2.7 V region. This is a remarkable result, considering that a linear decrease in this profile is usually observed for the majority of conducting polymer cathodes. PPy films obtained in BMIM BF{sub 4} presented globular morphology, with a special arrangement of nanoparticles constituting the globules; the EIS results indicated that this nanoscale structure may be contributing to a better definition of the redox characteristics during the PPy charge–discharge processes, as it happens for the well-organized structure of some metal oxides. - Highlights: • PPy was produced in an ionic liquid medium as active material for battery electrodes. • Discharge curves present a plateau not usual for conducting polymer electrodes. • RTIL used as synthesis electrolyte produced PPy with surface nanograins. • Morphological features explain the improved redox properties of PPy electrode. • Electrical properties of PPy grown in RTIL were accessed by impedance measurements.

  4. The effect of addition of primary positive salts, complex salt, on the ionic strength and rate constant at various temperatures by reaction kinetics

    Science.gov (United States)

    Kurade, S. S.; Ramteke, A. A.

    2018-05-01

    In this work, we have investigated the rate of reaction by using ionic strength at different temperatures. The main goal of this experiment is to determine the relation between ionic strength with reaction rate, reaction time and rate constant with temperature. It is observed that the addition of positive salt indicate the increasing ionic strength with increase in run time at various temperatures. Thus the temperature affects the speed of reaction and mechanism by which chemical reaction occurs and time variable plays vital role in the progress of reaction at different temperatures.

  5. Recent research directions in Fribourg: nuclear dynamics in resonances revealed by 2-dimensional EEL spectra, electron collisions with ionic liquids and electronic excitation of pyrimidine

    International Nuclear Information System (INIS)

    Allan, M.; Regeta, K.; Gorfinkiel, J.D.; Masin, Z.; Grimme, S.; Bannwarth, C.

    2016-01-01

    The article briefly reviews three subjects recently investigated in Fribourg: 1) electron collisions with surfaces of ionic liquids, 2) two-dimensional (2D) electron energy loss spectra and 3) resonances in absolute cross sections for electronic excitation of unsaturated compounds. Electron energy loss spectra of four ionic liquids revealed a number of excited states, including triplet states. A solution of a dye in an ionic liquid showed an energy-loss band of the solute, but not in all ionic liquids. 2D spectra reveal state-to-state information (given resonance to given final state) and are shown to be an interesting means to gain insight into dynamics of nuclear motion in resonances. Absolute cross sections for pyrimidine are reported as a function of scattering angle and as a function of electron energy. They reveal resonant structure which was reproduced very nicely by R-matrix calculations. The calculation provided an assignment of the resonances which reveals common patterns in compounds containing double bonds. (authors)

  6. Enhancing oxygen transport through Mixed-Ionic-and-Electronic-Conducting ceramic membranes

    Science.gov (United States)

    Yu, Anthony S.

    Ceramic membranes based on Mixed-Ionic-and-Electronic-Conducting (MIEC) oxides are capable of separating oxygen from air in the presence of an oxygen partial-pressure gradient. These MIEC membranes show great promise for oxygen consuming industrial processes, such as the production of syngas from steam reforming of natural gas (SRM), as well as for electricity generation in Solid Oxide Fuel Cells (SOFC). For both applications, the overall performance is dictated by the rate of oxygen transport across the membrane. Oxygen transport across MIEC membranes is composed of a bulk oxygen-ion diffusion process and surface processes, such as surface reactions and adsorption/desorption of gaseous reactants/products. The main goal of this thesis was to determine which process is rate-limiting in order to significantly enhance the overall rate of oxygen transport in MIEC membrane systems. The rate-limiting step was determined by evaluating the total resistance to oxygen transfer, Rtot. Rtot is the sum of a bulk diffusion resistance in the membrane itself, Rb, and interfacial loss components, Rs. Rb is a function of the membrane's ionic conductivity and thickness, while Rs arises primarily from slow surface-exchange kinetics that cause the P(O2) at the surfaces of the membrane to differ from the P(O 2) in the adjacent gas phases. Rtot can be calculated from the Nernst potential across the membrane and the measured oxygen flux. The rate-limiting process can be determined by evaluating the relative contributions of the various losses, Rs and Rb, to Rtot. Using this method, this thesis demonstrates that for most membrane systems, Rs is the dominating factor. In the development of membrane systems with high oxygen transport rates, thin membranes with high ionic conductivities are required to achieve fast bulk oxygen-ion diffusion. However, as membrane thickness is decreased, surface reaction kinetics become more important in determining the overall transport rate. The two

  7. Novel composite membranes based on PBI and dicationic ionic liquids for high temperature polymer electrolyte membrane fuel cells

    International Nuclear Information System (INIS)

    Hooshyari, Khadijeh; Javanbakht, Mehran; Adibi, Mina

    2016-01-01

    Two types of innovative composite membranes based on polybenzimidazole (PBI) containing dicationic ionic liquid 1,3-di(3-methylimidazolium) propane bis (trifluoromethylsulfonyl) imide (PDC 3 ) and monocationic ionic liquid 1-hexyl-3-methylimidazolium bis (trifluoromethanesulfonyl) imide (PMC 6 ) are prepared as electrolyte for high temperature fuel cells applications under anhydrous conditions. The analyses of results display promising characteristics such as high proton conductivity and thermal stability. Moreover the fuel cell performance of PA doped PDC 3 composite membranes is enhanced in comparison with PA doped PMC 6 and PA doped PBI membranes at high temperatures. Dicationic ionic liquid with high number of charge carriers provides well-developed ionic channels which form facile pathways and considerably develop the anhydrous proton conductivity. The highest proton conductivity of 81 mS/cm is achieved for PA doped PDC 3 composite membranes with PBI/IL mole ratio: 4 at 180 °C. A power density of 0.44 W/cm 2 is obtained at 0.5 V and 180 °C for PA doped PDC 3 composite membranes, which proves that these developed composite membranes can be considered as most promising candidates for high temperature fuel cell applications with enhanced proton conductivity.

  8. Potentiostatic electro-deposition of 241Am using room temperature ionic liquids

    International Nuclear Information System (INIS)

    Sankhe, R.H.; Mirashi, N.N.; Arijit Sengupta; Murali, M.S.

    2015-01-01

    An attempt was made for the potentiostatic electrodeposition of 241 Am using six different room temperature ionic liquids (RTILs). Effect of electrodeposition time on the % of electrodeposition of 241 Am, pH change of the solution and the temperature change of the systems were investigated. It was observed that for water immiscible RTILs, the least viscous RTIL gave the best yield (when mixed with iso-propanol), while for water miscible RTILs, reverse trend was observed (when mixed with water). Out of all water immiscible RTILs under consideration for the present case, the octyl-methyl-pyrrolidinium bis(trifluoromethylsulfonyl)imide (C 8 mpyNTf 2 ) in isopropanol was found to yield almost quantitative (99.6 %) electrodeposition of 241 Am within 45 min whereas the most effective system was found to be C 8 mimBr with ∼90 % of 241 Am deposited on the electrode for water miscible RTILs. To the best of our knowledge, this is the first approach ever been reported in the literature. (author)

  9. Influence of temperature and molecular structure on ionic liquid solvation layers.

    Science.gov (United States)

    Wakeham, Deborah; Hayes, Robert; Warr, Gregory G; Atkin, Rob

    2009-04-30

    Atomic force microscopy (AFM) force profiling is used to investigate the structure of adsorbed and solvation layers formed on a mica surface by various room temperature ionic liquids (ILs) ethylammonium nitrate (EAN), ethanolammonium nitrate (EtAN), ethylammonium formate (EAF), propylammonium formate (PAF), ethylmethylammonium formate (EMAF), and dimethylethylammonium formate (DMEAF). At least seven layers are observed for EAN at 14 degrees C (melting point 13 degrees C), decreasing as the temperature is increased to 30 degrees C due to thermal energy disrupting solvophobic forces that lead to segregation of cation alkyl tails from the charged ammonium and nitrate moieties. The number and properties of the solvation layers can also be controlled by introducing an alcohol moiety to the cation's alkyl tail (EtAN), or by replacing the nitrate anion with formate (EAF and PAF), even leading to the detection of distinct cation and anion sublayers. Substitution of primary by secondary or tertiary ammonium cations reduces the number of solvation layers formed, and also weakens the cation layer adsorbed onto mica. The observed solvation and adsorbed layer structures are discussed in terms of the intermolecular cohesive forces within the ILs.

  10. Temperature and anion responsive self-assembly of ionic liquid block copolymers coating gold nanoparticles

    Science.gov (United States)

    Li, Junbo; Zhao, Jianlong; Wu, Wenlan; Liang, Ju; Guo, Jinwu; Zhou, Huiyun; Liang, Lijuan

    2016-06-01

    In this paper, double hydrophilic ionic liquid block copolymers (ILBCs), poly poly[1-methyl-3-(2-methacryloyloxy propylimidazolium bromine)]- block-(N-isopropylacrylamide) (PMMPImB- b-PNIPAAm) was first synthesized by reversible additionfragmentation chain transfer (RAFT) and then attached on the surface of gold nanoparticles (Au NPs) via a strong gold-sulfur bonding for preparing hybrid nanoparticles (PMMPImB- b-PNIPAAm-@-Au NPs). The hybrid NPs had a three layers micelle-like structure, including a gold core, thermo-responsive inner shell and anion responsive outer corona. The self-assembling behavior of thermal- and anion-response from shell and corona were respectively investigated by change of temperature and addition of (CF3SO2)2N-. The results showed the hybrid NPs retained a stable dispersion beyond the lower critical solution temperature (LCST) because of the space or electrostatic protecting by outer PMMPImB. However, with increasing concentration of (CF3SO2)2N-, the micellization of self-assembling PMMPImB- b-PNIPAAm-@-Au NPs was induced to form micellar structure containing the core with hydrophobic PMMPImB-(CF3SO2)2N- surrounded by composite shell of Au NPs-PNIPAAm via the anionresponsive properties of ILBCs. These results indicated that the block copolymers protected plasmonic nanoparticles remain self-assembling properties of block copolymers when phase transition from outer corona polymer.

  11. Antimicrobial active silver nanoparticles and silver/polystyrene core-shell nanoparticles prepared in room-temperature ionic liquid

    International Nuclear Information System (INIS)

    An Jing; Wang Desong; Luo Qingzhi; Yuan Xiaoyan

    2009-01-01

    Uniform silver nanoparticles and silver/polystyrene core-shell nanoparticles were successfully synthesized in a room temperature ionic liquid, 1-n-butyl-3-methylimidazolium tetrafluoroborate ([BMIM].BF 4 ). [BMIM].BF 4 plays a protective role to prevent the nanoparticles from aggregation during the preparation process. Transmission electron micrographs confirm that both silver nanoparticles and core-shell nanoparticles are regular spheres with the sizes in the range of 5-15 nm and 15-25 nm, respectively. The X-ray diffraction analysis reveals the face-centered cubic geometry of silver nanoparticles. The as-prepared nanoparticles were also characterized by Fourier transform infrared spectroscopy, Raman spectroscopy, UV-vis diffuse reflectance spectroscopy and X-ray photoelectron spectroscopy. In addition, antimicrobial activities against E. coli and S. aureus were studied and the results show that both silver nanoparticles and core-shell nanoparticles possess excellent antimicrobial activities. The antimicrobial mechanism of the as-prepared nanoparticles was discussed.

  12. Enhancement of superconducting transition temperature in FeSe electric-double-layer transistor with multivalent ionic liquids

    Science.gov (United States)

    Miyakawa, Tomoki; Shiogai, Junichi; Shimizu, Sunao; Matsumoto, Michio; Ito, Yukihiro; Harada, Takayuki; Fujiwara, Kohei; Nojima, Tsutomu; Itoh, Yoshimitsu; Aida, Takuzo; Iwasa, Yoshihiro; Tsukazaki, Atsushi

    2018-03-01

    We report on an enhancement of the superconducting transition temperature (Tc) of the FeSe-based electric-double-layer transistor (FeSe-EDLT) by applying the multivalent oligomeric ionic liquids (ILs). The IL composed of dimeric cation (divalent IL) enables a large amount of charge accumulation on the surface of the FeSe ultrathin film, resulting in inducing electron-rich conduction even in a rather thick 10 nm FeSe channel. The onset Tc in FeSe-EDLT with the divalent IL is enhanced to be approaching about 50 K at the thin limit, which is about 7 K higher than that in EDLT with conventional monovalent ILs. The enhancement of Tc is a pronounced effect of the application of the divalent IL, in addition to the large capacitance, supposing preferable interface formation of ILs driven by geometric and/or Coulombic effect. The present finding strongly indicates that multivalent ILs are powerful tools for controlling and improving physical properties of materials.

  13. Photoelectron spectroscopic studies of the electronic structure of some metals and ionic solids

    International Nuclear Information System (INIS)

    Poole, R.T.

    1974-01-01

    The source of u.v. radiation used was a d.c. glow discharge in either helium or neon gas. Photons of energy 40.81 eV from a helium discharge were used predominantly for measurements on solid state materials. The design, construction and operating characteristics of the inert gas discharge lamp are presented and the operating characteristics of the lamp were investigated in order to improve progressively the design of the lamp and also to determine under what operating conditions the production of 40.81 eV radiation is maximized. The electron optics of a spherical electrostatic (π/2) -sector, electron energy analyzer and its transmission properties, for monoenergetic and nonmonoenergetic photoelectron sources, under constant resolution mode of operation are presented. In order to perform quantitative measurements energy calibration techniques for solid and gaseous samples and an intensity calibration technique for angular distribution measurements was developed. Measurements of the splittings of the 3d, 4d and 5d bands in some metals in the atomic number range Z = 29 - 83 are compared to free atom values and evidence for crystal field effects is presented. Measurements on eighteen alkali halides are compared with the predictions of the Born model for strongly ionic crystals. (author)

  14. Development of new techniques for scanning electron microscope observation using ionic liquid

    Energy Technology Data Exchange (ETDEWEB)

    Arimoto, Satoshi; Sugimura, Masaharu; Kageyama, Hitoshi [Department of Applied Chemistry, Graduate School of Engineering, Osaka University, Suita, Osaka 565-0871 (Japan); JST, CREST, Kawaguchi, Saitama 332-0012 (Japan); Torimoto, Tsukasa [Department of Crystalline Materials Science, Graduate School of Engineering, Nagoya University, Nagoya 464-8603 (Japan); JST, CREST, Kawaguchi, Saitama 332-0012 (Japan); Kuwabata, Susumu [Department of Applied Chemistry, Graduate School of Engineering, Osaka University, Suita, Osaka 565-0871 (Japan); JST, CREST, Kawaguchi, Saitama 332-0012 (Japan)], E-mail: kuwabata@chem.eng.osaka-u.ac.jp

    2008-09-01

    Based on our previous discovery that ionic liquid (IL) can be observed by a scanning electron microscope (SEM) without charging the liquid, we have developed several novel techniques for SEM observation. Coating of insulating sample with IL is useful for providing electronic conductivity to the samples like metal or carbon coating by vacuum vapor deposition. In this case, dilution of the IL with appropriate volatile solvent like alcohol is effective for coating thin layer of IL on the sample. As a biological sample, seaweed including IL was attempted to be observed by SEM. A seaweed leaf swollen by water was put in an IL bath and the bath was put in an outgassed desiccator to replace water in the seaweed leaf with IL. The resulting sample gave a SEM image of the swollen seaweed whose thickness was several times larger than dried one. Furthermore, the introduction of the IL in vacuum chamber allowed us to develop the in situ electrochemical SEM observation system. Using this system, we observed changes in polypyrrole film thickness caused by the redox reaction of the film and the electrochemical deposition of silver and its oxidative dissolution. It was also found that the energy dispersive X-ray fluorescence (EDX) analysis was available even for the electrode polarized in IL.

  15. Development of new techniques for scanning electron microscope observation using ionic liquid

    International Nuclear Information System (INIS)

    Arimoto, Satoshi; Sugimura, Masaharu; Kageyama, Hitoshi; Torimoto, Tsukasa; Kuwabata, Susumu

    2008-01-01

    Based on our previous discovery that ionic liquid (IL) can be observed by a scanning electron microscope (SEM) without charging the liquid, we have developed several novel techniques for SEM observation. Coating of insulating sample with IL is useful for providing electronic conductivity to the samples like metal or carbon coating by vacuum vapor deposition. In this case, dilution of the IL with appropriate volatile solvent like alcohol is effective for coating thin layer of IL on the sample. As a biological sample, seaweed including IL was attempted to be observed by SEM. A seaweed leaf swollen by water was put in an IL bath and the bath was put in an outgassed desiccator to replace water in the seaweed leaf with IL. The resulting sample gave a SEM image of the swollen seaweed whose thickness was several times larger than dried one. Furthermore, the introduction of the IL in vacuum chamber allowed us to develop the in situ electrochemical SEM observation system. Using this system, we observed changes in polypyrrole film thickness caused by the redox reaction of the film and the electrochemical deposition of silver and its oxidative dissolution. It was also found that the energy dispersive X-ray fluorescence (EDX) analysis was available even for the electrode polarized in IL

  16. Electronic desalting for controlling the ionic environment in droplet-based biosensing platforms

    Energy Technology Data Exchange (ETDEWEB)

    Swaminathan, Vikhram Vilasur [Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801 (United States); Dak, Piyush; Alam, Muhammad A., E-mail: rbashir@illinois.edu, E-mail: alam@purdue.edu [School of Electrical and Computer Engineering, Purdue University, West Lafayette, Indiana 47907 (United States); Reddy, Bobby; Duarte-Guevara, Carlos; Zhong, Yu [Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801 (United States); Salm, Eric [Department of Bioengineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801 (United States); Fischer, Andrew [Abbott Laboratories, 1921 Hurd Drive, Dept. 8482 LC2 M/S 2-33, Irving, Texas 75038 (United States); Liu, Yi-Shao [Taiwan Semiconductor Manufacturing Company, Hsinchu 300-78, Taiwan (China); Bashir, Rashid, E-mail: rbashir@illinois.edu, E-mail: alam@purdue.edu [Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801 (United States); Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801 (United States); Department of Bioengineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801 (United States)

    2015-02-02

    The ability to control the ionic environment in saline waters and aqueous electrolytes is useful for desalination as well as electronic biosensing. We demonstrate a method of electronic desalting at micro-scale through on-chip micro electrodes. We show that, while desalting is limited in bulk solutions with unlimited availability of salts, significant desalting of ≥1 mM solutions can be achieved in sub-nanoliter volume droplets with diameters of ∼250 μm. Within these droplets, by using platinum-black microelectrodes and electrochemical surface treatments, we can enhance the electrode surface area to achieve >99% and 41% salt removal in 1 mM and 10 mM salt concentrations, respectively. Through self-consistent simulations and experimental measurements, we demonstrate that conventional double-layer theory over-predicts the desalting capacity and, hence, cannot be used to model systems that are mass limited or undergoing significant salt removal from the bulk. Our results will provide a better understanding of capacitive desalination, as well as a method for salt manipulation in high-throughput droplet-based microfluidic sensing platforms.

  17. Thermophysical properties of ionic liquid {1-butyl-3-methylimidazolium bromide [bmim][Br] in alkoxyalkanols + water} mixtures at different temperatures

    International Nuclear Information System (INIS)

    Pal, Amalendu; Kumar, Harsh; Kumar, Bhupinder; Sharma, Pooja; Kaur, Kirtanjot

    2013-01-01

    Highlights: ► Densities and speeds of sound of alkoxyalkanols in [bmim][Br]. ► Synthesis of room temperature ionic liquid [bmim][Br]. ► Partial molar volumes and compressibility of transfer. ► Apparent molar expansivities and the Hepler’s constant were calculated. ► Solute–solute and solute–solvent interactions and the structural changes of the solutes. - Abstract: The interactions of alkoxyalkanols with the ionic liquid 1-butyl-3-methylimidazolium bromide [bmim][Br] as a function of temperature were investigated by combination of volumetric and acoustic methods. The density, ρ, and speed of sound, u, of ethylene glycol monomethyl ether, diethylene glycol monomethyl ether, and triethylene glycol monomethyl ether (0.00–1.01 mol·kg −1 ) in aqueous 1-butyl-3-methylimidazolium bromide solutions ranging from pure water to 0.29 mass% of ionic liquid have been measured at T = (288.15, 298.15 and 308.15) K and atmospheric pressure. The apparent molar volume (V φ ) and adiabatic compressibility (K φ,S ) of alkoxyalkanols in aqueous ionic liquid solution were determined at the measured temperatures. The partial molar volume (V φ 0 ) and partial molar adiabatic compressibility (K φ 0 ) of alkoxyalkanols at infinite dilution were evaluated. Transfer volumes (ΔV φ 0 ) and transfer adiabatic compressibility (ΔK φ 0 ) at infinite dilution from water to aqueous ionic liquid solution were also calculated. The temperature dependence of the apparent molar volume was used to calculate apparent molar expansivity (φ E 0 ) and the Hepler’s constant values, (∂ 2 V φ 0 /∂T 2 ). The results were explained on the basis of competing patterns of interactions of co-solvent and the solute.

  18. An experimental study of perovskite-structured mixed ionic- electronic conducting oxides and membranes

    Science.gov (United States)

    Zeng, Pingying

    In recent decades, ceramic membranes based on mixed ionic and electronic conducting (MIEC) perovskite-structured oxides have received many attentions for their applications for air separation, or as a membrane reactor for methane oxidation. While numerous perovskite oxide materials have been explored over the past two decades; there are hardly any materials with sufficient practical economic value and performance for large scale applications, which justifies continuing the search for new materials. The main purposes of this thesis study are: (1) develop several novel SrCoO3-delta based MIEC oxides, SrCoCo1-xMxO3-delta, based on which membranes exhibit excellent oxygen permeability; (2) investigate the significant effects of the species and concentration of the dopants M (metal ions with fixed valences) on the various properties of these membranes; (3) investigate the significant effects of sintering temperature on the microstructures and performance of oxygen permeation membranes; and (4) study the performance of oxygen permeation membranes as a membrane reactor for methane combustion. To stabilize the cubic phase structure of the SrCoO3-delta oxide, various amounts of scandium was doped into the B-site of SrCoO 3-delta to form a series of new perovskite oxides, SrScxCoCo 1-xO3-delta (SSCx, x = 0-0.7). The significant effects of scandium-doping concentration on the phase structure, electrical conductivity, sintering performance, thermal and structural stability, cathode performance, and oxygen permeation performance of the SSCx membranes, were systematically studied. Also for a more in-depth understanding, the rate determination steps for the oxygen transport process through the membranes were clarified by theoretical and experimental investigation. It was found that only a minor amount of scandium (5 mol%) doping into the B-site of SrCoO3-delta can effectively stabilize the cubic phase structure, and thus significantly improve the electrical conductivity and

  19. Spectroscopic measurements of plasma temperatures and electron number density in a uranium hollow cathode discharge lamp

    International Nuclear Information System (INIS)

    Shah, M.L.; Suri, B.M.; Gupta, G.P.

    2015-01-01

    The HCD (Hollow Cathode Discharge) lamps have been used as a source of free atoms of any metal, controllable by direct current in the lamp. The plasma parameters including neutral species temperature, atomic excitation temperature and electron number density in a see-through type, homemade uranium hollow cathode discharge lamp with neon as a buffer gas have been investigated using optical emission spectroscopic techniques. The neutral species temperature has been measured using the Doppler broadening of a neon atomic spectral line. The atomic excitation temperature has been measured using the Boltzmann plot method utilizing uranium atomic spectral lines. The electron number density has been determined from the Saha-Boltzmann equation utilizing uranium atomic and ionic spectral lines. To the best of our knowledge, all these three plasma parameters are simultaneously measured for the first time in a uranium hollow cathode discharge lamp

  20. Electrical double layer modulation of hybrid room temperature ionic liquid/aqueous buffer interface for enhanced sweat based biosensing.

    Science.gov (United States)

    Jagannath, Badrinath; Muthukumar, Sriram; Prasad, Shalini

    2018-08-03

    We have investigated the role of kosmotropic anionic moieties and chaotropic cationic moieties of room temperature hydrophilic ionic liquids in enhancing the biosensing performance of affinity based immunochemical biosensors in human sweat. Two ionic liquids, 1-butyl-3-methylimidazolium tetrafluoroborate (BMIM[BF 4 ]) and choline dihydrogen phosphate (Choline[DHP]) were investigated in this study with Choline[DHP] being more kosmotropic in nature having a more protein stabilizing effect based on the hofmeister series. Non-faradaic interfacial charge transfer has been employed as the mechanism for evaluating the formation and the biosensing of capture probe antibodies in room temperature ionic liquids (RTILs)/aqueous human sweat interface. The charge of the ionic moieties were utilized to form compact electrical double layers around the antibodies for enhancing the stability of the antibody capture probes, which was evaluated through zeta potential measurements. The zeta potential measurements indicated stability of antibodies due to electrostatic repulsion of the RTIL charged moieties encompassing the antibodies, thus preventing any aggregation. Here, we report for the first time of non-faradaic electrochemical impedance spectroscopy equivalent circuit model analysis for analyzing and interpreting affinity based biosensing at hybrid electrode/ionic liquid-aqueous sweat buffer interface guided by the choice of the ionic liquid. Interleukin-6 (IL-6) and cortisol two commonly occurring biomarkers in human sweat were evaluated using this method. The limit of detection (LOD) obtained using both ionic liquids for IL-6 was 0.2 pg mL -1 with cross-reactivity studies indicating better performance of IL-6 detection using Choline[DHP] and no response to cross-reactive molecule. The LOD of 0.1 ng/mL was achieved for cortisol and the cross-reactivity studies indicated that cortisol antibody in BMIM[BF 4 ] did not show any signal response to cross-reactive molecules

  1. Application of a room temperature ionic liquid for nuclear spent fuel reprocessing: speciation of trivalent europium and solvatation effects

    International Nuclear Information System (INIS)

    Moutiers, G.; Mekki, S.; Billard, I.

    2007-01-01

    One of the solutions proposed for the optimization of the long term storage and conditioning of spent nuclear fuel is to separate actinide and lanthanide both from each other and from other less radioactive metallic species. The industrial proposed processes, based on liquid liquid extraction steps, involve solvents with non negligible vapour pressure and may generate contaminated liquid wastes that will have to be reprocessed. During the last decade, some room-temperature ionic liquids have been studied and integrated into industrial processes. The interest on this class of solvent came out from their 'green' properties (non volatile, non flammable, recyclable, etc...), but also from the variability of their physico-chemical properties (stability, hydrophobicity, viscosity) as a function of the RTIL chemical composition. Indeed, it has been shown that classical chemical industrial processes could be transferred into those media, even more improved, while a certain number of difficulties arising from using traditional solvent can be avoided. In this respect, it could be promising to investigate the ability to use room temperature ionic liquid into the spent nuclear fuel reprocessing field. The aim of this this study is to test the ability of the specific ionic liquid bumimTf 2 N to allow trivalent europium extraction. The choice of this metal is based on the chemical analogy with trivalent minor actinides Curium and Americium which are contributing the greatest part of the long-lived high level radioactive wastes. Handling these elements needs to be very cautious for the safety and radioprotection aspect. Moreover, europium is a very sensitive luminescent probe to its environment even at the microscopic scale. The report is structured with four parts. In a first chapter, we present the main physico-chemical properties of an imidazolium-based ionic liquid family, and then we choose the ionic liquid bumimTf 2 N for the whole thesis and start with the electrochemical

  2. A summary of high-temperature electronics research and development

    International Nuclear Information System (INIS)

    Thome, F.V.; King, D.B.

    1991-01-01

    Current and future needs in automative, aircraft, space, military, and well logging industries require operation of electronics at higher temperatures than today's accepted limit of 395 K. Without the availability of high-temperature electronics, many systems must operate under derated conditions or must accept severe mass penalties required by coolant systems to maintain electronic temperatures below critical levels. This paper presents ongoing research and development in the electronics community to bring high-temperature electronics to commercial realization. Much of this work was recently reviewed at the First International High-Temperature Electronics Conference held 16--20 June 1991 in Albuquerque, New Mexico. 4 refs., 1 tab

  3. Orientational dynamics in a room temperature ionic liquid: Are angular jumps predominant?

    Science.gov (United States)

    Das, Suman; Mukherjee, Biswaroop; Biswas, Ranjit

    2018-05-01

    Reorientational dynamics of the constituent ions in a room temperature ionic liquid, 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM][PF6]), are explored via molecular dynamics simulations, and several features of orientation dynamics are summarized. The anion, [PF6]-, not only exhibits a higher propensity to orientation jumps than the cation, [BMIM]+ but also accesses a wider jump angle distribution and larger peak-angle. Jump and waiting time distributions for both the ions depict power-law dependences, suggesting temporally heterogeneous dynamics for the medium. This heterogeneity feature is further highlighted by the finding that the simulated first rank (ℓ = 1) and second rank (ℓ = 2) average reorientational correlation times reflect a severe break-down of Debye's ℓ(ℓ + 1) law for orientational diffusion in an isotropic homogeneous medium. Simulated average H-bond lifetime resides between the mean orientation jump and waiting times, while the structural H-bond relaxation suggests, as in normal liquids, a pronounced presence of translational motion of the partnering ions. Average simulated jump trajectories reveal a strong rotation-translation coupling and indicate relatively larger changes in spatial and angular arrangements for the anion during an orientation jump. In fact, a closer inspection of all these results points toward more heterogeneous dynamics for [PF6]- than [BMIM]+. This is a new observation and may simply be linked to the ion-size. However, such a generalization warrants further study.

  4. The Mechanism of Room-Temperature Ionic-Liquid-Based Electrochemical CO₂ Reduction: A Review.

    Science.gov (United States)

    Lim, Hyung-Kyu; Kim, Hyungjun

    2017-03-28

    Electrochemical CO₂ conversion technology is becoming indispensable in the development of a sustainable carbon-based economy. While various types of electrocatalytic systems have been designed, those based on room-temperature ionic liquids (RTILs) have attracted considerable attention because of their high efficiencies and selectivities. Furthermore, it should be possible to develop more advanced electrocatalytic systems for commercial use because target-specific characteristics can be fine-tuned using various combinations of RTIL ions. To achieve this goal, we require a systematic understanding of the role of the RTIL components in electrocatalytic systems, however, their role has not yet been clarified by experiment or theory. Thus, the purpose of this short review is to summarize recent experimental and theoretical mechanistic studies to provide insight into and to develop guidelines for the successful development of new CO₂ conversion systems. The results discussed here can be summarized as follows. Complex physical and chemical interactions between the RTIL components and the reaction intermediates, in particular at the electrode surface, are critical for determining the activity and selectivity of the electrocatalytic system, although no single factor dominates. Therefore, more fundamental research is required to understand the physical, chemical, and thermodynamic characteristics of complex RTIL-based electrocatalytic systems.

  5. Ideal gas solubilities and solubility selectivities in a binary mixture of room-temperature ionic liquids.

    Science.gov (United States)

    Finotello, Alexia; Bara, Jason E; Narayan, Suguna; Camper, Dean; Noble, Richard D

    2008-02-28

    This study focuses on the solubility behaviors of CO2, CH4, and N2 gases in binary mixtures of imidazolium-based room-temperature ionic liquids (RTILs) using 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([C2mim][Tf2N]) and 1-ethyl-3-methylimidazolium tetrafluoroborate ([C2mim][BF4]) at 40 degrees C and low pressures (approximately 1 atm). The mixtures tested were 0, 25, 50, 75, 90, 95, and 100 mol % [C2mim][BF4] in [C2mim][Tf2N]. Results show that regular solution theory (RST) can be used to describe the gas solubility and selectivity behaviors in RTIL mixtures using an average mixture solubility parameter or an average measured mixture molar volume. Interestingly, the solubility selectivity, defined as the ratio of gas mole fractions in the RTIL mixture, of CO2 with N2 or CH4 in pure [C2mim][BF4] can be enhanced by adding 5 mol % [C2mim][Tf2N].

  6. Effects of Room-Temperature Ionic Liquids on Zebra Mussels (Dreissena polymorpha)

    Science.gov (United States)

    Costello, D. M.; Bernot, R. J.; Lamberti, G. A.

    2005-05-01

    Zebra mussels (Dreissena polymorpha) are exotic bivalves that are widely distributed in eastern North America. We propose that this nuisance organism could serve as a model species for studies of aquatic toxicology. We tested zebra mussels response to room-temperature ionic liquids (ILs), which are being synthesized as environmentally friendly alternatives to volatile organic solvents. Volatile organic solvents contribute to atmospheric pollution and ozone depletion, whereas ILs are non-volatile and less harmful to the atmosphere. Although ILs would contribute significantly less to air pollution, little is known about their potential effects on aquatic ecosystems. In 72-hour toxicity tests, we determined the acute effects of three imidazolium-based ILs (1-butyl-3-methylimidazolium bromide (bmimBr), 1-hexyl-3-methylimidazolium bromide (hmimBr), and 1-octyl-3-methylimidazolium bromide (omimBr)) on the survival of zebra mussels. As alkyl chain length decreased, median lethal concentration (LC50) decreased from 1291 mg L-1 for bmimBr, to 105 mg L-1 for hmimBr, and 21.2 mg L-1 for omimBr. For bivalve mussels, the toxicities of these ILs are comparable to the toxicities of commonly used industrial solvents (e.g., toluene, benzene). This study presents a foundation for using zebra mussels in toxicity studies as well as possible models for less common Unionid mussels.

  7. Oxidative desulfurization of fuels catalyzed by Fenton-like ionic liquids at room temperature.

    Science.gov (United States)

    Jiang, Yunqing; Zhu, Wenshuai; Li, Huaming; Yin, Sheng; Liu, Hua; Xie, Qingjie

    2011-03-21

    Oxidation of the sulfur-containing compounds benzothiophene (BT), dibenzothiophene (DBT), and 4,6-dimethyldibenzothiophene (4,6-DMDBT) has been studied in a desulfurization system composed of model oil, hydrogen peroxide, and different types of ionic liquids [(C(8)H(17))(3)CH(3)N]Cl/FeCl(3), [(C(8)H(17))(3)CH(3)N]Cl/CuCl(2), [(C(8)H(17))(3)CH(3)N]Cl/ZnCl(2), [(C(8)H(17))(3)CH(3)N]Cl/SnCl(2), [(C(4)H(9))(3)CH(3)N]Cl/FeCl(3), [C(10)H(21)(CH(3))(3)N]Cl/FeCl(3), [(C(10)H(21))(2)(CH(3))(2)N]Cl/FeCl(3). Deep desulfurization is achieved in the Fenton-like ionic liquid [(C(8)H(17))(3)CH(3)N]Cl/FeCl(3) at 25 °C for 1 h. The desulfurization of DBT reaches 97.9%, in consuming very low amount of [(C(8)H(17))(3)CH(3)N]Cl/FeCl(3) (only 0.702 mmol). The reaction conditions, for example, the amount of [(C(8)H(17))(3)CH(3)N]Cl/FeCl(3) or H(2)O(2), the temperature, and the molar ratio of FeCl(3) to [(C(8)H(17))(3)CH(3)N]Cl, are investigated for this system. The oxidation reactivity of the different sulfur-containing compounds is found to decrease in the order of DBT>BT>4,6-DMDBT. The desulfurization system can be recycled six times without significant decrease in activity. The sulfur level of FCC gasoline could be reduced from 360 ppm to 110 ppm. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Atomistic simulation of ionic and electronic defects in YBa2Cu3O7

    International Nuclear Information System (INIS)

    Baetzold, R.C.

    1988-01-01

    An empirical two-body potential model has been developed in order to describe the electronic and ionic defect properties of orthorhombic YBa 2 Cu 3 O 7 . The potential model was derived starting from known potentials and calculated potentials and fits the crystal structure to better than 0.03 A for the major bonds. Oxygen vacancy formation and hole trapping as a localized polaron are most favorable at the chain oxygen ion site 1. Hole trapping on Cu + ions is most favorable for ions in the copper-oxygen plane. Divalent impurity ions such as Ni/sup 2+/, Zn/sup 2+/, and Cd/sup 2+/ can dissolve in the crystal preferentially at the Cu/sup 2+/ plane site 2. On the other hand, trivalent impurities such as Al/sup 3+/, Fe/sup 3+/, and Ga/sup 3+/ dissolve in the crystal at the chain Cu/sup 2+/ site 1 along with the incorporation of oxygen ions. Anions such as S/sup 2-/, Cl - or F - would preferentially substitute for O/sup 2-/ at sites near the Cu/sup 2+/ chain position

  9. Temperature dependence measurements and structural characterization of trimethyl ammonium ionic liquids with a highly polar solvent.

    Science.gov (United States)

    Attri, Pankaj; Venkatesu, Pannuru; Hofman, T

    2011-08-25

    We report the synthesis and characterization of a series of an ammonium ionic liquids (ILs) containing acetate, dihydrogen phosphate, and hydrogen sulfate anions with a common cation. To characterize the thermophysical properties of these newly synthesized ILs with the highly polar solvent N,N-dimethylformamide (DMF), precise measurements such as densities (ρ) and ultrasonic sound velocities (u) over the whole composition range have been performed at atmospheric pressure and over wide temperature ranges (25-50 °C). The excess molar volume (V(E)) and the deviation in isentropic compressibilities (Δκ(s)) were predicted using these temperature dependence properties as a function of the concentration of ILs. The Redlich-Kister polynomial was used to correlate the results. The ILs investigated in the present study included trimethylammonium acetate [(CH(3))(3)NH][CH(3)COO] (TMAA), trimethylammonium dihydrogen phosphate [(CH(3))(3)NH][H(2)PO(4)] (TMAP), and trimethylammonium hydrogen sulfate [(CH(3))(3)NH][HSO(4)] (TMAS). The intermolecular interactions and structural effects were analyzed on the basis of the measured and the derived properties. In addition, the hydrogen bonding between ILs and DMF has been demonstrated using semiempirical calculations with help of Hyperchem 7. A qualitative analysis of the results is discussed in terms of the ion-dipole, ion-pair interactions, and hydrogen bonding between ILs and DMF molecules and their structural factors. The influence of the anion of the protic IL, namely, acetate (CH(3)COO), dihydrogen phosphate (H(2)PO(4)), and hydrogen sulfate (HSO(4)), on the thermophysical properties is also provided. © 2011 American Chemical Society

  10. Novel room temperature ionic liquid for fluorescence enhancement of Eu3+ and Tb3+

    International Nuclear Information System (INIS)

    Shyamala Devi, V.; Maji, S.; Viswanathan, K.S.

    2011-01-01

    The newly prepared ionic liquid, 1-butyl-3-methylimidazolium benzoate, ([bmim][BA]), was found to enhance the fluorescence of Eu 3+ and Tb 3+ . The fluorescence enhancement resulted from a sensitization of the lanthanide fluorescence by the benzoate anion of the ionic liquid, [bmim][BA], and a reduction in the non-radiative channels in the non-aqueous environment provided by the ionic liquid. However, the fluorescence enhancement of the lanthanides in the ionic liquid was limited due to the operation of the inner filter effect, which resulted from the strong absorption of the benzoate. The inner filter effect was minimized by observing the Eu 3+ fluorescence using a front face geometry and also by diluting the lanthanide-[bmim][BA] system, using another ionic liquid, 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([bmim][Tf 2 N]), as a solvent. In the case of Tb 3+ , the emission from the lanthanide was masked by the strong emission from the ionic liquid in the region 450-580 nm. The long lived Tb 3+ emission was therefore observed using delayed gated detection, where an appropriate delay was used to discriminate against the short lived emission from the ionic liquid. The large fluorescence enhancement due to ligand sensitized fluorescence observed with [bmim][BA] diluted in [bmim][Tf 2 N], leads to nanomolar detection of the lanthanides. This is, to the best of our knowledge, the first report of an ionic liquid being employed for ligand sensitized fluorescence enhancement of lanthanides. - Research highlights: →The use of an ionic liquid to enhance the fluorescence of lanthanides, Eu 3+ and Tb 3+ is discussed in this paper. → This study represents the first report of the use of a tailored ionic liquid for the purposes of fluorescence enhancement. → The fluorescence enhancement is achieved both a process of ligand sensitization, as well as reducing the non-radiative decay channels. → The first point is achieved by the use of an anion capable

  11. Self-consistent modelling of electrochemical strain microscopy in mixed ionic-electronic conductors: Nonlinear and dynamic regimes

    Science.gov (United States)

    Varenyk, O. V.; Silibin, M. V.; Kiselev, D. A.; Eliseev, E. A.; Kalinin, S. V.; Morozovska, A. N.

    2015-08-01

    The frequency dependent Electrochemical Strain Microscopy (ESM) response of mixed ionic-electronic conductors is analyzed within the framework of Fermi-Dirac statistics and the Vegard law, accounting for steric effects from mobile donors. The emergence of dynamic charge waves and nonlinear deformation of the surface in response to bias applied to the tip-surface junction is numerically explored. The 2D maps of the strain and concentration distributions across the mixed ionic-electronic conductor and bias-induced surface displacements are calculated. The obtained numerical results can be applied to quantify the ESM response of Li-based solid electrolytes, materials with resistive switching, and electroactive ferroelectric polymers, which are of potential interest for flexible and high-density non-volatile memory devices.

  12. Self-consistent modelling of electrochemical strain microscopy in mixed ionic-electronic conductors: Nonlinear and dynamic regimes

    Energy Technology Data Exchange (ETDEWEB)

    Varenyk, O. V.; Morozovska, A. N., E-mail: sergei2@ornl.gov, E-mail: anna.n.morozovska@gmail.com [Institute of Physics, National Academy of Sciences of Ukraine, 46, pr. Nauky, 03028 Kyiv (Ukraine); Silibin, M. V. [National Research University of Electronic Technology “MIET,” 124498 Moscow (Russian Federation); Kiselev, D. A. [National University of Science and Technology “MISiS,” 119049 Moscow, Leninskiy pr. 4 (Russian Federation); Eliseev, E. A. [Institute for Problems of Materials Science, NAS of Ukraine, Krjijanovskogo 3, 03142 Kyiv (Ukraine); Kalinin, S. V., E-mail: sergei2@ornl.gov, E-mail: anna.n.morozovska@gmail.com [The Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States)

    2015-08-21

    The frequency dependent Electrochemical Strain Microscopy (ESM) response of mixed ionic-electronic conductors is analyzed within the framework of Fermi-Dirac statistics and the Vegard law, accounting for steric effects from mobile donors. The emergence of dynamic charge waves and nonlinear deformation of the surface in response to bias applied to the tip-surface junction is numerically explored. The 2D maps of the strain and concentration distributions across the mixed ionic-electronic conductor and bias-induced surface displacements are calculated. The obtained numerical results can be applied to quantify the ESM response of Li-based solid electrolytes, materials with resistive switching, and electroactive ferroelectric polymers, which are of potential interest for flexible and high-density non-volatile memory devices.

  13. Novel Fission-Product Separation Based on Room-Temperature Ionic Liquids

    International Nuclear Information System (INIS)

    Rogers, Robin D.

    2004-01-01

    This project has demonstrated that Sr2+ and Cs+ can be selectively extracted from aqueous solutions into ionic liquids using crown ethers and that unprecedented large distribution coefficients can be achieved for these fission products. The volume of secondary wastes can be significantly minimized with this new separation technology. Through the current EMSP funding, the solvent extraction technology based on ionic liquids has been shown to be viable and can potentially provide the most efficient separation of problematic fission products from high level wastes. The key results from the current funding period are the development of highly selective extraction process for cesium ions based on crown ethers and calixarenes, optimization of selectivities of extractants via systematic change of ionic liquids, and investigation of task-specific ionic liquids incorporating both complexant and solvent characteristics

  14. Theoretical study for pyridinium-based ionic liquid 1-ethylpyridinium trifluoroacetate: synthesis mechanism, electronic structure, and catalytic reactivity.

    Science.gov (United States)

    Zhu, Xueying; Cui, Peng; Zhang, Dongju; Liu, Chengbu

    2011-07-28

    By performing density functional theory calculations, we have studied the synthesis mechanism, electronic structure, and catalytic reactivity of a pyridinium-based ionic liquid, 1-ethylpyridinium trifluoroacetate ([epy](+)[CF(3)COO](-)). It is found that the synthesis of the pyridinium salt follows a S(N)2 mechanism. The electronic structural analyses show that multiple H bonds are generally involved in the pyridinium-based ionic liquid, which may play a decisive role for stabilizing the ionic liquid. The cation-anion interaction mainly involves electron transfer between the lone pair of the oxygen atom in the anion and the antibonding orbital of the C*-H bond (C* denotes the carbon atom at the ortho-position of nitrogen atom in the cation). This present work has also given clearly the catalytic mechanism of [epy](+)[CF(3)COO](-) toward to the Diels-Alder (D-A) reaction of acrylonitrile with 2-methyl-1,3-butadiene. Both the cation and anion are shown to play important roles in promoting the D-A reaction. The cation [epy](+), as a Lewis acid, associates the C≡N group by C≡N···H H bond to increase the polarity of the C═C double bond in acrylonitrile, while the anion CF(3)COO(-) links with the methyl group in 2-methyl-1,3-butadiene by C-H···O H bond, which weakens the electron-donating capability of methyl and thereby lowers the energy barrier of the D-A reaction. The present results are expected to provide valuable information for the design and application of pyridinium-based ionic liquids. © 2011 American Chemical Society

  15. Amperometric Ion-Selective Electrode for Alkali Metal Cations Based on a Room-Temperature Ionic Liquid Membrane

    Czech Academy of Sciences Publication Activity Database

    Langmaier, Jan; Trojánek, Antonín; Samec, Zdeněk

    2009-01-01

    Roč. 21, 17-18 (2009), s. 1977-1983 ISSN 1040-0397 R&D Projects: GA MŠk ME08098; GA AV ČR IAA400400704 Institutional research plan: CEZ:AV0Z40400503 Keywords : room-temperature ionic liquid * alkali metals * Crown ether * cyclic voltammetry * amperometric ion-selective elkectrode Subject RIV: CG - Electrochemistry Impact factor: 2.630, year: 2009

  16. Enhancement of photovoltaic performance of flexible perovskite solar cells by means of ionic liquid interface modification in a low temperature all solution process

    Science.gov (United States)

    Chu, Weijing; Yang, Junyou; Jiang, Qinghui; Li, Xin; Xin, Jiwu

    2018-05-01

    The quality of interface between the electron transport layer (ETL) and perovskite is very crucial to the photovoltaic performance of a flexible perovskite solar cell fabricated under low-temperature process. This work demonstrates a room temperature ionic liquid modification strategy to the interface between ZnO layer and MAPbI3 film for high performance flexible perovskite solar cells based on a PET substrate. [BMIM]BF4 ionic liquid modification can significantly improve the surface quality and wettability of the ZnO ETL, thus greatly increase the charge mobility of ZnO ETL and improve the crystalline of perovskite film based on it. Moreover, the dipolar polarization layer among the ZnO ETL with perovskite, built by modification, can adjust the energy level between the ZnO ETL and perovskite and facilitates the charge extraction. Therefore, an overall power conversion efficiency (PCE) of 12.1% have been achieved under standard illumination, it increases by 1.4 times of the flexible perovskite solar cells on a pristine ZnO ETL.

  17. Structure and dynamics of POPC bilayers in water solutions of room temperature ionic liquids

    International Nuclear Information System (INIS)

    Benedetto, Antonio; Bingham, Richard J.; Ballone, Pietro

    2015-01-01

    Molecular dynamics simulations in the NPT ensemble have been carried out to investigate the effect of two room temperature ionic liquids (RTILs), on stacks of phospholipid bilayers in water. We consider RTIL compounds consisting of chloride ([bmim][Cl]) and hexafluorophosphate ([bmim][PF 6 ]) salts of the 1-buthyl-3-methylimidazolium ([bmim] + ) cation, while the phospholipid bilayer is made of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC). Our investigations focus on structural and dynamical properties of phospholipid and water molecules that could be probed by inelastic and quasi-elastic neutron scattering measurements. The results confirm the fast incorporation of [bmim] + into the lipid phase already observed in previous simulations, driven by the Coulomb attraction of the cation for the most electronegative oxygens in the POPC head group and by sizeable dispersion forces binding the neutral hydrocarbon tails of [bmim] + and of POPC. The [bmim] + absorption into the bilayer favours the penetration of water into POPC, causes a slight but systematic thinning of the bilayer, and further stabilises hydrogen bonds at the lipid/water interface that already in pure samples (no RTIL) display a lifetime much longer than in bulk water. On the other hand, the effect of RTILs on the diffusion constant of POPC (D POPC ) does not reveal a clearly identifiable trend, since D POPC increases upon addition of [bmim][Cl] and decreases in the [bmim][PF 6 ] case. Moreover, because of screening, the electrostatic signature of each bilayer is only moderately affected by the addition of RTIL ions in solution. The analysis of long wavelength fluctuations of the bilayers shows that RTIL sorption causes a general decrease of the lipid/water interfacial tension and bending rigidity, pointing to the destabilizing effect of RTILs on lipid bilayers

  18. Structure and dynamics of POPC bilayers in water solutions of room temperature ionic liquids

    Energy Technology Data Exchange (ETDEWEB)

    Benedetto, Antonio [School of Physics, University College Dublin, Dublin 4 (Ireland); Laboratory for Neutron Scattering and Imaging, Paul Scherrer Institut, 5232 Villigen (Switzerland); Bingham, Richard J. [York Centre for Complex Systems Analysis, University of York, York YO10 5GE (United Kingdom); Ballone, Pietro [Center for Life Nano Science @Sapienza, Istituto Italiano di Tecnologia (IIT), 00185 Roma (Italy); Department of Physics, Università di Roma “La Sapienza,” 00185 Roma (Italy)

    2015-03-28

    Molecular dynamics simulations in the NPT ensemble have been carried out to investigate the effect of two room temperature ionic liquids (RTILs), on stacks of phospholipid bilayers in water. We consider RTIL compounds consisting of chloride ([bmim][Cl]) and hexafluorophosphate ([bmim][PF{sub 6}]) salts of the 1-buthyl-3-methylimidazolium ([bmim]{sup +}) cation, while the phospholipid bilayer is made of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC). Our investigations focus on structural and dynamical properties of phospholipid and water molecules that could be probed by inelastic and quasi-elastic neutron scattering measurements. The results confirm the fast incorporation of [bmim]{sup +} into the lipid phase already observed in previous simulations, driven by the Coulomb attraction of the cation for the most electronegative oxygens in the POPC head group and by sizeable dispersion forces binding the neutral hydrocarbon tails of [bmim]{sup +} and of POPC. The [bmim]{sup +} absorption into the bilayer favours the penetration of water into POPC, causes a slight but systematic thinning of the bilayer, and further stabilises hydrogen bonds at the lipid/water interface that already in pure samples (no RTIL) display a lifetime much longer than in bulk water. On the other hand, the effect of RTILs on the diffusion constant of POPC (D{sub POPC}) does not reveal a clearly identifiable trend, since D{sub POPC} increases upon addition of [bmim][Cl] and decreases in the [bmim][PF{sub 6}] case. Moreover, because of screening, the electrostatic signature of each bilayer is only moderately affected by the addition of RTIL ions in solution. The analysis of long wavelength fluctuations of the bilayers shows that RTIL sorption causes a general decrease of the lipid/water interfacial tension and bending rigidity, pointing to the destabilizing effect of RTILs on lipid bilayers.

  19. (Liquid + liquid) equilibria of {benzene + cyclohexane + two ionic liquids} at different temperature and atmospheric pressure

    International Nuclear Information System (INIS)

    Sakal, Salem A.; Shen, Chong; Li, Chun-xi

    2012-01-01

    Highlights: ► (Liquid + liquid) equilibrium for two quaternary and two ternary systems were measured. ► The components include cyclohexane, benzene, [MIM][BF4], [MIM][ClO4] and [MMIM][DMP]. ► The (liquid + liquid) equilibrium data can be well correlated by the NRTL model. ► Separation of benzene and cyclohexane by pure ILs and their mixtures were discussed. - Abstract: (Liquid + liquid) equilibrium data of the following ternary and quaternary systems at different temperatures and mass fractions of ionic liquids (ILs) were measured at atmospheric pressure, i.e., {cyclohexane + benzene + 1,3-dimethylimidazolium dimethylphosphate ([MMIM][DMP])} at 298.2 K, {cyclohexane + benzene + 1-methylimidazolium tetrafluoroborate ([MIM][BF 4 ])} at 338.2 K, {cyclohexane + benzene + [MIM][BF 4 ] + [MMIM][DMP]} at (298.2 and 313.2) K, and {cyclohexane + benzene + 1-methylimidazolium perchlorate [MIM][ClO 4 ] + [MMIM][DMP]} at 298.2 K. The results indicate that both selectivity and distribution factor of the IL mixture for benzene are lower than that of pure IL [MMIM][DMP] at a specified condition, and decrease with the increase of the mass fraction of [MIM][BF 4 ] or [MIM][ClO 4 ] in its mixture of [MMIM][DMP] and the mole fraction of benzene. The extremely high selectivity of [MIM][BF 4 ] and [MIM][ClO 4 ] for aromatic compounds as predicted by the COSMOS-RS model is not justified by the present experimental results, and on the contrary, they show a relatively lower selectivity and extraction capacity for benzene than [MMIM][DMP].

  20. Observation of electron temperature profile in HL-1M tokamak

    International Nuclear Information System (INIS)

    Cao Jianyong; Xu Deming; Ding Xuantong

    2000-01-01

    The principle and method of the electron temperature measurement by means of electron cyclotron emission (ECE) have been described. Several results under different conditions on HL-1M tokamak have been given. The hollow profile of electron temperature appears in some stages, such as current rising, pellet injection and impurity concentration in the plasma centre. When the bias voltage is applied, the electron temperature profile become steeper. All of the phenomena are related with the transport in plasma centre

  1. Synthesis of non-ionic and ionic resins for BEP intaglio inks curing by electron-beam radiation. Annual report

    International Nuclear Information System (INIS)

    Bauer, B.J.; Dickens, B.

    1992-01-01

    The inks currently used to print US postage stamps on web presses are dried by heat evaporation of solvents. Emission of solvents into the atmosphere is governed by Local and Federal Government Regulations. Reduction of these emissions to acceptable levels can be accomplished by either of two methods available to the BEP. The work was part of a continuing effort to produce resins for use in formulation of intaglio inks for the printing of postage stamps and security documents. The inks are to be cured by exposure to an electron beam. The uncured inks are cleaned from the roller and wiping blade by washing the wiping blade with neutral water or with caustic water. Laboratory scale work on the urethane/polyethylene oxide/methacrylate resins has now been concluded and information on the synthesis has been provided to BEP for patenting and scaleup. Some effort on nonionic resins continued into FY88

  2. Magnetomotive room temperature dicationic ionic liquid: a new concept toward centrifuge-less dispersive liquid-liquid microextraction.

    Science.gov (United States)

    Beiraghi, Asadollah; Shokri, Masood; Seidi, Shahram; Godajdar, Bijan Mombani

    2015-01-09

    A new centrifuge-less dispersive liquid-liquid microextraction technique based on application of magnetomotive room temperature dicationic ionic liquid followed by electrothermal atomic absorption spectrometry (ETAAS) was developed for preconcentration and determination of trace amount of gold and silver in water and ore samples, for the first time. Magnetic ionic liquids not only have the excellent properties of ionic liquids but also exhibit strong response to an external magnetic field. These properties provide more advantages and potential application prospects for magnetic ionic liquids than conventional ones in the fields of extraction processes. In this work, thio-Michler's ketone (TMK) was used as chelating agent to form Ag/Au-TMK complexes. Several important factors affecting extraction efficiency including extraction time, rate of vortex agitator, pH of sample solution, concentration of the chelating agent, volume of ionic liquid as well as effects of interfering species were investigated and optimized. Under the optimal conditions, the limits of detection (LOD) were 3.2 and 7.3ngL(-1) with the preconcentration factors of 245 and 240 for Au and Ag, respectively. The precision values (RSD%, n=7) were 5.3% and 5.8% at the concentration level of 0.05μgL(-1) for Au and Ag, respectively. The relative recoveries for the spiked samples were in the acceptable range of 96-104.5%. The results demonstrated that except Hg(2+), no remarkable interferences are created by other various ions in the determination of Au and Ag, so that the tolerance limits (WIon/WAu or Ag) of major cations and anions were in the range of 250-1000. The validated method was successfully applied for the analysis of Au and Ag in some water and ore samples. Copyright © 2014 Elsevier B.V. All rights reserved.

  3. Electrochemomechanics with flexoelectricity and modelling of electrochemical strain microscopy in mixed ionic-electronic conductors

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Pengfei; Hu, Shuling; Shen, Shengping, E-mail: sshen@mail.xjtu.edu.cn [State Key Laboratory for Strength and Vibration of Mechanical Structures, School of Aerospace, Xi' an Jiaotong University, Xi' an 710049 (China)

    2016-08-14

    Recently, a new scanning probe microscopy approach, referred to as electrochemical strain microscopy (ESM), for probing local ionic flows and electrochemical reactions in solids based on the bias-strain coupling was proposed by Morozovska et al. Then, a series of theoretical papers for analyzing the image formation and spectroscopic mechanism of ESM were published within the framework of Fermi-Dirac statistics, the Vegard law, the direct flexoelectric coupling effect, the electrostriction effect, and so on. However, most of the models in these papers are limited to the partial coupling or particular process, and numerically solved by using decoupling approximation. In this paper, to model the ESM measurement with the coupling electrical-chemical-mechanical process, the chemical Gibbs function variational principle for the thermal electrical chemical mechanical fully coupling problem is proposed. The fully coupling governing equations are derived from the variational principle. When the tip concentrates the electric field within a small volume of the material, the inhomogeneous electric field is induced. So, both direct and inverse flexoelectric effects should be taken into account. Here, the bulk defect electrochemical reactions are also taken into account, which are usually omitted in the existing works. This theory can be used to deal with coupling problems in solids, including conductors, semiconductors, and piezoelectric and non-piezoelectric dielectrics. As an application of this work, a developed initial-boundary value problem is solved numerically in a mixed ion-electronic conductor. Numerical results show that it is meaningful and necessary to consider the bulk defect chemical reaction. Besides, the chemical reaction and the flexoelectric effect have an interactive influence on each other. This work can provide theoretical basis for the ESM as well as investigating the bulk chemical reaction process in solids.

  4. Surface structure determinations of crystalline ionic thin films grown on transition metal single crystal surfaces by low energy electron diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Roberts, Joel Glenn [Univ. of California, Berkeley, CA (United States)

    2000-05-01

    The surface structures of NaCl(100), LiF(100) and alpha-MgCl2(0001) adsorbed on various metal single crystals have been determined by low energy electron diffraction (LEED). Thin films of these salts were grown on metal substrates by exposing the heated metal surface to a molecular flux of salt emitted from a Knudsen cell. This method of investigating thin films of insulators (ionic salts) on a conducting substrate (metal) circumvents surface charging problems that plagued bulk studies, thereby allowing the use of electron-based techniques to characterize the surface.

  5. A Density Functional Theory Study of the Ionic and Electronic Transport Mechanisms in LiFeBO3 Battery Electrodes

    DEFF Research Database (Denmark)

    Loftager, Simon; García Lastra, Juan Maria; Vegge, Tejs

    2016-01-01

    electrochemical effects can be explained by an intrinsically low Li-ion and electron/hole-polaron mobility in Li0.5FeBO3 due to high activation barriers for both the ionic and electronic transport. These studies include the effects of the experimentally reported commensurate modulation. We have also investigated...... with the formation of intermediate phases is linked to the intrinsically poor properties of the Li0.5FeBO3 phase rather than to the presence of interfaces between different phases....

  6. The physicochemical properties of the low-temperature ionic liquid silver bromide-1-butyl-3-methylimidazolium bromide

    Science.gov (United States)

    Grishina, E. P.; Ramenskaya, L. M.; Pimenova, A. M.

    2009-11-01

    The physicochemical properties of the low-temperature ionic liquid based on 1-butyl-3-methylimidazolium bromide (BMImBr) and silver bromide were studied. Differential scanning calorimetry, Fourier transform IR spectroscopy, densimetry, viscometry, and conductometry measurements were performed to determine the dependences of the parameters under study on the concentration of AgBr. It was shown that the temperature and concentration behavior of the physicochemical properties of BMImBr-AgBr melts characterized the interaction between the system components with the formation of complex particles.

  7. Effects of temperature and anion species on CO2 permeability and CO2/N2 separation coefficient through ionic liquid membranes

    International Nuclear Information System (INIS)

    Jindaratsamee, Pinyarat; Shimoyama, Yusuke; Morizaki, Hironobu; Ito, Akira

    2011-01-01

    The permeability of carbon dioxide (CO 2 ) through imidazolium-based ionic liquid membranes was measured by a sweep gas method. Six species of ionic liquids were studied in this work as follows: [emim][BF 4 ], [bmim][BF 4 ], [bmim][PF 6 ], [bmim][Tf 2 N], [bmim][OTf], and [bmim][dca]. The ionic liquids were supported with a polyvinylidene fluoride porous membrane. The measurements were performed at T = (303.15 to 343.15) K. The partial pressure difference between feed and permeate sides was 0.121 MPa. The permeability of the CO 2 increases with temperature for the all ionic liquid species. Base on solution diffusion theory, it can be explained that the diffusion coefficient of CO 2 in an ionic liquid affects the temperature dependence more strongly than the solubility coefficient. The greatest permeability was obtained with the [bmim][Tf 2 N] membrane. The membrane of [bmim][PF 6 ] presents the lowest permeability. The separation coefficient between CO 2 and N 2 through the ionic liquid membranes was also investigated at the volume fraction of CO 2 at feed side 0.10. The separation coefficient decreases with the increase of temperature for the all ionic liquid species. The membrane of [emim][BF 4 ] and [bmim][BF 4 ] gives the highest separation coefficient at constant temperature. The lowest separation coefficient was obtained from [bmim][Tf 2 N] membrane which presents the highest permeability of CO 2 .

  8. High Power Electric Double-Layer Capacitors based on Room-Temperature Ionic Liquids and Nanostructured Carbons

    Science.gov (United States)

    Perez, Carlos R.

    The efficient storage of electrical energy constitutes both a fundamental challenge for 21st century science and an urgent requirement for the sustainability of our technological civilization. The push for cleaner renewable forms of energy production, such as solar and wind power, strongly depends on a concomitant development of suitable storage methods to pair with these intermittent sources, as well as for mobile applications, such as vehicles and personal electronics. In this regard, Electrochemical Double-Layer Capacitors (supercapacitors) represent a vibrant area of research due to their environmental friendliness, long lifetimes, high power capability, and relative underdevelopment when compared to electrochemical batteries. Currently supercapacitors have gravimetric energies one order of magnitude lower than similarly advanced batteries, while conversly enjoying a similar advantage over them in terms of power. The challenge is to increase the gravimentric energies and conserve the high power. On the material side, research focuses on highly porous supports and electrolytes, the critical components of supercapacitors. Through the use of electrolyte systems with a wider electrochemical stability window, as well as properly tailored carbon nanomaterials as electrodes, significant improvements in performance are possible. Room Temperature Ionic Liquids and Carbide-Derived Carbons are promising electrolytes and electrodes, respectively. RTILs have been shown to be stable at up to twice the voltage of organic solvent-salt systems currently employed in supercapacitors, and CDCs are tunable in pore structure, show good electrical conductivity, and superior demonstrated capability as electrode material. This work aims to better understand the interplay of electrode and electrolyte parameters, such as pore structure and ion size, in the ultimate performance of RTIL-based supercapacitors in terms of power, energy, and temperature of operation. For this purpose, carbon

  9. Effects of emitted electron temperature on the plasma sheath

    International Nuclear Information System (INIS)

    Sheehan, J. P.; Kaganovich, I. D.; Wang, H.; Raitses, Y.; Sydorenko, D.; Hershkowitz, N.

    2014-01-01

    It has long been known that electron emission from a surface significantly affects the sheath surrounding that surface. Typical fluid theory of a planar sheath with emitted electrons assumes that the plasma electrons follow the Boltzmann relation and the emitted electrons are emitted with zero energy and predicts a potential drop of 1.03T e /e across the sheath in the floating condition. By considering the modified velocity distribution function caused by plasma electrons lost to the wall and the half-Maxwellian distribution of the emitted electrons, it is shown that ratio of plasma electron temperature to emitted electron temperature significantly affects the sheath potential when the plasma electron temperature is within an order of magnitude of the emitted electron temperature. When the plasma electron temperature equals the emitted electron temperature the emissive sheath potential goes to zero. One dimensional particle-in-cell simulations corroborate the predictions made by this theory. The effects of the addition of a monoenergetic electron beam to the Maxwellian plasma electrons were explored, showing that the emissive sheath potential is close to the beam energy only when the emitted electron flux is less than the beam flux

  10. Ionic Impurity in a Bose-Einstein Condensate at Submicrokelvin Temperatures

    Science.gov (United States)

    Kleinbach, K. S.; Engel, F.; Dieterle, T.; Löw, R.; Pfau, T.; Meinert, F.

    2018-05-01

    Rydberg atoms immersed in a Bose-Einstein condensate interact with the quantum gas via electron-atom and ion-atom interaction. To suppress the typically dominant electron-neutral interaction, Rydberg states with a principal quantum number up to n =190 are excited from a dense and tightly trapped micron-sized condensate. This allows us to explore a regime where the Rydberg orbit exceeds the size of the atomic sample by far. In this case, a detailed line shape analysis of the Rydberg excitation spectrum provides clear evidence for ion-atom interaction at temperatures well below a microkelvin. Our results may open up ways to enter the quantum regime of ion-atom scattering for the exploration of charged quantum impurities and associated polaron physics.

  11. Time-dependent density functional theory for the charging kinetics of electric double layer containing room-temperature ionic liquids.

    Science.gov (United States)

    Lian, Cheng; Zhao, Shuangliang; Liu, Honglai; Wu, Jianzhong

    2016-11-28

    Understanding the charging kinetics of electric double layers is of fundamental importance for the design and development of novel electrochemical devices such as supercapacitors and field-effect transistors. In this work, we study the dynamic behavior of room-temperature ionic liquids using a classical time-dependent density functional theory that accounts for the molecular excluded volume effects, the electrostatic correlations, and the dispersion forces. While the conventional models predict a monotonic increase of the surface charge with time upon application of an electrode voltage, our results show that dispersion between ions results in a non-monotonic increase of the surface charge with the duration of charging. Furthermore, we investigate the effects of van der Waals attraction between electrode/ionic-liquid interactions on the charging processes.

  12. Liquid-liquid miscibility and volumetric properties of aqueous solutions of ionic liquids as a function of temperature

    International Nuclear Information System (INIS)

    Wang Silu; Jacquemin, Johan; Husson, Pascale; Hardacre, Christopher; Costa Gomes, Margarida F.

    2009-01-01

    The volumetric properties of seven {water + ionic liquid} binary mixtures have been studied as a function of temperature from (293 to 343) K. The phase behaviour of the systems was first investigated using a nephelometric method and excess molar volumes were calculated from densities measured using an Anton Paar densimeter and fitted using a Redlich-Kister type equation. Two ionic liquids fully miscible with water (1-butyl-3-methylimidazolium tetrafluoroborate ([C 1 C 4 Im][BF 4 ]) and 1-ethyl-3-methylimidazolium ethylsulfate ([C 1 C 2 Im][EtSO 4 ])) and five ionic liquids only partially miscible with water (1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([C 1 C 2 Im][NTf 2 ]), 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([C 1 C 4 Im][NTf 2 ]), 1-butyl-3-methylimidazolium hexafluorophosphate ([C 1 C 4 Im][PF 6 ]), 1-butyl-3-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide ([C 1 C 4 Pyrro][NTf 2 ]), and butyltrimethylammonium bis(trifluoromethylsulfonyl)imide ([N 4111 ][NTf 2 ])) were chosen. Small excess volumes (less than 0.5 cm 3 . mol -1 at 298 K) are obtained compared with the molar volumes of the pure components (less than 0.3% of the molar volume of the pure ionic liquid). For all the considered systems, except for {[C 1 C 2 Im][EtSO 4 ] + water}, positive excess molar volumes were calculated. Finally, an increase of the non-ideality character is observed for all the systems as temperature increases.

  13. Hydrolysis, formation and ionization constants at 250C, and at high temperature-high ionic strength

    International Nuclear Information System (INIS)

    Phillips, S.L.; Phillips, C.A.; Skeen, J.

    1985-02-01

    Thermochemical data for nuclear waste disposal are compiled. The resulting computerized database consists of critically evaluated data on Gibbs energy of formation, enthalpy of formation, entropy and heat capacity of selected substances for about 16 elements at 25 0 C and zero ionic strength. Elements covered are Am, As, Br, C, Cl, F, I, Mo, Np, N, O, P, Pu, Si, Sr, S, and U. Values of these thermodynamic properties were used to calculate equilibrium quotients for hydrolysis, complexation and ionization reactions up to 300 0 C and 3 ionic strength, for selected chemical reactions

  14. Electronic phase separation and high temperature superconductors

    International Nuclear Information System (INIS)

    Kivelson, S.A.

    1994-01-01

    The authors review the extensive evidence from model calculations that neutral holes in an antiferromagnet separate into hole-rich and hole-poor phases. All known solvable limits of models of holes in a Heisenberg antiferromagnet exhibit this behavior. The authors show that when the phase separation is frustrated by the introduction of long-range Coulomb interactions, the typical consequence is either a modulated (charge density wave) state or a superconducting phase. The authors then review some of the strong experimental evidence supporting an electronically-driven phase separation of the holes in the cuprate superconductors and the related Ni oxides. Finally, the authors argue that frustrated phase separation in these materials can account for many of the anomalous normal state properties of the high temperature superconductors and provide the mechanism of superconductivity. In particular, it is shown that the T-linear resistivity of the normal state is a paraconductivity associated with a novel composite pairing, although the ordered superconducting state is more conventional

  15. Guggenheim's rule and the enthalpy of vaporization of simple and polar fluids, molten salts, and room temperature ionic liquids.

    Science.gov (United States)

    Weiss, Volker C

    2010-07-22

    One of Guggenheim's many corresponding-states rules for simple fluids implies that the molar enthalpy of vaporization (determined at the temperature at which the pressure reaches 1/50th of its critical value, which approximately coincides with the normal boiling point) divided by the critical temperature has a value of roughly 5.2R, where R is the universal gas constant. For more complex fluids, such as strongly polar and ionic fluids, one must expect deviations from Guggenheim's rule. Such a deviation has far-reaching consequences for other empirical rules related to the vaporization of fluids, namely Guldberg's rule and Trouton's rule. We evaluate these characteristic quantities for simple fluids, polar fluids, hydrogen-bonding fluids, simple inorganic molten salts, and room temperature ionic liquids (RTILs). For the ionic fluids, the critical parameters are not accessible to direct experimental observation; therefore, suitable extrapolation schemes have to be applied. For the RTILs [1-n-alkyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imides, where the alkyl chain is ethyl, butyl, hexyl, or octyl], the critical temperature is estimated by extrapolating the surface tension to zero using Guggenheim's and Eotvos' rules; the critical density is obtained using the linear-diameter rule. It is shown that the RTILs adhere to Guggenheim's master curve for the reduced surface tension of simple and moderately polar fluids, but that they deviate significantly from his rule for the reduced enthalpy of vaporization of simple fluids. Consequences for evaluating the Trouton constant of RTILs, the value of which has been discussed controversially in the literature, are indicated.

  16. Room-temperature ionic liquids and composite materials: platform technologies for CO(2) capture.

    Science.gov (United States)

    Bara, Jason E; Camper, Dean E; Gin, Douglas L; Noble, Richard D

    2010-01-19

    Clean energy production has become one of the most prominent global issues of the early 21st century, prompting social, economic, and scientific debates regarding energy usage, energy sources, and sustainable energy strategies. The reduction of greenhouse gas emissions, specifically carbon dioxide (CO(2)), figures prominently in the discussions on the future of global energy policy. Billions of tons of annual CO(2) emissions are the direct result of fossil fuel combustion to generate electricity. Producing clean energy from abundant sources such as coal will require a massive infrastructure and highly efficient capture technologies to curb CO(2) emissions. Current technologies for CO(2) removal from other gases, such as those used in natural gas sweetening, are also capable of capturing CO(2) from power plant emissions. Aqueous amine processes are found in the vast majority of natural gas sweetening operations in the United States. However, conventional aqueous amine processes are highly energy intensive; their implementation for postcombustion CO(2) capture from power plant emissions would drastically cut plant output and efficiency. Membranes, another technology used in natural gas sweetening, have been proposed as an alternative mechanism for CO(2) capture from flue gas. Although membranes offer a potentially less energy-intensive approach, their development and industrial implementation lags far behind that of amine processes. Thus, to minimize the impact of postcombustion CO(2) capture on the economics of energy production, advances are needed in both of these areas. In this Account, we review our recent research devoted to absorptive processes and membranes. Specifically, we have explored the use of room-temperature ionic liquids (RTILs) in absorptive and membrane technologies for CO(2) capture. RTILs present a highly versatile and tunable platform for the development of new processes and materials aimed at the capture of CO(2) from power plant flue gas and

  17. Microfluidic room temperature ionic liquid droplet generation depending on the hydrophobicity and interfacial tension

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, Jung Wook; Chang, Woo-Jin [University of Wisconsin-Milwaukee, Milwaukee (United States); Choi, Joo Hyung; Koo, Yoon Mo [Department of Biological Engineering, Incheon (Korea, Republic of); Choi, Bum Joon; Lee, Gyu Do; Lee, Sang Woo [Yonsei University, Wonju (Korea, Republic of)

    2016-01-15

    We have characterized micro-droplet generation using water immiscible hexafluorophosphate ([PF{sub 6}])- and bis(trifluoro methylsulfonyl)imide ([Tf{sub 2}N])-based room temperature ionic liquids (RTILs). The interfacial tension between total 7 RTILs and phosphate buffered saline (PBS) was measured using a tensiometer for the first time. PBS is one of the most commonly used buffer solutions in cell-related researches. The measured interfacial tension ranges from 8.51 to 11.62 and from 9.56 to 13.19 for [Tf{sub 2}N]- and [PF{sub 6}]-based RTILs, respectively. The RTILs micro-droplets were generated in a microfluidic device. The micro-droplet size and generation frequency were determined based on continuous monitoring of light transmittance at the interface in microchannel. The size of RTIL micro-droplets was inversely proportional to the increase of PBS solution flow rate and RTILs hydrophobicity, while droplet generation frequency was proportional to those changes. The measured size of RTILs droplets ranged from 0.6 to 10.5 nl, and from 1.0 to 17.1 nl for [Tf{sub 2}N]- and [PF{sub 6}]-based RTILs, respectively. The measured frequency of generated RTILs droplets ranged from 2.3 to 37.2 droplet/min, and from 2.7 to 17.1 droplet/min for [Tf{sub 2}N]- and [PF{sub 6}]-based RTILs, respectively. The capillary numbers were calculated depending on the RTILs, and ranged from 0.51x10{sup -3} to 1.06x10{sup -3} and from 5.00x10{sup -3} to 8.65x10{sup -3}, for [Tf{sub 2}N]- and [PF{sub 6}]-based RTILs, respectively. The interfacial tension between RTILs and PBS will contribute to developing bioprocesses using immiscible RTILs. Also, the RTILs micro-droplets will enable the high-throughput monitoring of various biological and chemical reactions using RTILs as new reaction media.

  18. Thermally-responsive, nonflammable phosphonium ionic liquid electrolytes for lithium metal batteries: operating at 100 degrees celsius† †Electronic supplementary information (ESI) available: Detailed ionic liquids synthesis, characterization, conductivity, cyclic voltammetry, battery cycling and those of other compositions; SEM images; energy density calculation. See DOI: 10.1039/c5sc01518a Click here for additional data file.

    Science.gov (United States)

    Lin, X.; Kavian, R.; Lu, Y.; Hu, Q.; Shao-Horn, Y.

    2015-01-01

    Rechargeable batteries such as Li ion/Li metal batteries are widely used in the electronics market but the chemical instability of the electrolyte limits their use in more demanding environmental conditions such as in automotive, oil exploration, or mining applications. In this study, a series of alkyl phosphonium ionic liquid electrolyte are described with high thermal stability and solubility for LiTFSI. A lithium metal battery (LMB) containing a tailored phosphonium ionic liquid/LiTFSI electrolyte operates at 100 °C with good specific capacities and cycling stability. Substantial capacity is maintained during 70 cycles or 30 days. Instant on-off battery operation is realized via the significant temperature dependence of the electrolyte material, demonstrating the robustness and potential for use at high temperature. PMID:28757963

  19. Enhanced Esterification Conversion in a Room Temperature Ionic Liquid by Integrated Water Removal with Pervaporation

    Czech Academy of Sciences Publication Activity Database

    Izák, Pavel; Mateus, N.M.M.; Afonso, C. A. M.; Crespo, J.G.

    2005-01-01

    Roč. 41, č. 2 (2005), s. 141-145 ISSN 1383-5866 Institutional research plan: CEZ:AV0Z40720504 Keywords : pervaporation * ionic liquids * esterification reaction Subject RIV: CI - Industrial Chemistry, Chemical Engineering Impact factor: 1.752, year: 2005

  20. What Can we learn from Raman spectroscopy and model calculations on room temperature ionic liquids?

    DEFF Research Database (Denmark)

    Berg, Rolf W.

    2006-01-01

    Traditionally ionic liquids involve inorganic hygroscopic substances that need to be contained under protective atmospheres, e.g. in sealed ampoules. Experimental methods to study the chemistry inside closed ampoules are limited, and one popular technique has been and still is Raman scattering be...

  1. Novel Fission Product Separation Based on Room-Temperature Ionic liquids

    International Nuclear Information System (INIS)

    Hussey, Charles L.

    2005-01-01

    The effective extraction of Cs+ and Sr2+ into a relatively new and heretofore untested hydrophobic ionic liquid, tri-n-butylmethylammonium bis[(trifluoromethyl)sulfonyl]imide was demonstrated with calix[4]arene-bis(tert-octylbenzo-crown-6) and dicyclohexano-18-crown-6, respectively. The coordinated Cs+ and Sr2+ were subsequently removed from the ionic liquid extraction solvent by an electrochemical reduction process carried out at mercury electrodes. This process is non-destructive, permitting the ionic liquid and ionophores to be recycled. Although the process is based on mercury electrodes, this is a benefit rather than a detriment because the liquid mercury containing the Cs and Sr can be easily transported to another electrochemical cell where the Cs and Sr could be electrochemically recovered from the mercury amalgam and concentrated into a minimum volume of water or some other inexpensive solvent. This should facilitate the development of a suitable waste form for the extracted Cs+ and Sr2+. Thus, the feasibility of the proposed ionic liquid-based extraction cycle for the removal of 137Cs+ and 90Sr2+ from simulated aqueous tank waste was demonstrated

  2. Electrolytic conductivity and molar heat capacity of two aqueous solutions of ionic liquids at room-temperature: Measurements and correlations

    International Nuclear Information System (INIS)

    Lin Peiyin; Soriano, Allan N.; Leron, Rhoda B.; Li Menghui

    2010-01-01

    As part of our systematic study on physicochemical characterization of ionic liquids, in this work, we report new measurements of electrolytic conductivity and molar heat capacity for aqueous solutions of two 1-ethyl-3-methylimidazolium-based ionic liquids, namely: 1-ethyl-3-methylimidazolium dicyanamide and 1-ethyl-3-methylimidazolium 2-(2-methoxyethoxy) ethylsulfate, at normal atmospheric condition and for temperatures up to 353.2 K. The electrolytic conductivity and molar heat capacity were measured by a commercial conductivity meter and a differential scanning calorimeter (DSC), respectively. The estimated experimental uncertainties for the electrolytic conductivity and molar heat capacity measurements were ±1% and ±2%, respectively. The property data are reported as functions of temperature and composition. A modified empirical equation from another researcher was used to correlate the temperature and composition dependence of the our electrolytic conductivity results. An excess molar heat capacity expression derived using a Redlich-Kister type equation was used to represent the temperature and composition dependence of the measured molar heat capacity and calculated excess molar heat capacity of the solvent systems considered. The correlations applied represent the our measurements satisfactorily as shown by an acceptable overall average deviation of 6.4% and 0.1%, respectively, for electrolytic conductivity and molar heat capacity.

  3. Coupled ion temperature gradient and trapped electron mode to electron temperature gradient mode gyrokinetic simulations

    International Nuclear Information System (INIS)

    Waltz, R. E.; Candy, J.; Fahey, M.

    2007-01-01

    Electron temperature gradient (ETG) transport is conventionally defined as the electron energy transport at high wave number (high-k) where ions are adiabatic and there can be no ion energy or plasma transport. Previous gyrokinetic simulations have assumed adiabatic ions (ETG-ai) and work on the small electron gyroradius scale. However such ETG-ai simulations with trapped electrons often do not have well behaved nonlinear saturation unless fully kinetic ions (ki) and proper ion scale zonal flow modes are included. Electron energy transport is separated into ETG-ki at high-k and ion temperature gradient-trapped electron mode (ITG/TEM) at low-k. Expensive (more computer-intensive), high-resolution, large-ion-scale flux-tube simulations coupling ITG/TEM and ETG-ki turbulence are presented. These require a high effective Reynolds number R≡[k(max)/k(min)] 2 =μ 2 , where μ=[ρ si /ρ si ] is the ratio of ion to electron gyroradii. Compute times scale faster than μ 3 . By comparing the coupled expensive simulations with (1) much cheaper (less compute-intensive), uncoupled, high-resolution, small, flux-tube ETG-ki and with (2) uncoupled low-resolution, large, flux-tube ITG/TEM simulations, and also by artificially turning ''off'' the low-k or high-k drives, it appears that ITG/TEM and ETG-ki transport are not strongly coupled so long as ETG-ki can access some nonadiabatic ion scale zonal flows and both high-k and low-k are linearly unstable. However expensive coupled simulations are required for physically accurate k-spectra of the transport and turbulence. Simulations with μ≥30 appear to represent the physical range μ>40. ETG-ki transport measured in ion gyro-Bohm units is weakly dependent on μ. For the mid-radius core tokamak plasma parameters studied, ETG-ki is about 10% of the electron energy transport, which in turn is about 30% of the total energy transport (with negligible ExB shear). However at large ExB shear sufficient to quench the low-k ITG

  4. Development of electron temperature measuring system by silicon drift detector

    International Nuclear Information System (INIS)

    Song Xianying; Yang Jinwei; Liao Min

    2007-12-01

    Soft X-ray spectroscopy with two channels Silicon Drift Detector (SDD) are adopted for electron temperature measuring on HL-2A tokamak in 2005. The working principle, design and first operation of the SDD soft X-ray spectroscopy are introduced. The measuring results of electron temperature are also presented. The results show that the SDD is very good detector for electron temperature measuring on HL-2A tokamak. These will become a solid basic work to establish SDD array for electron temperature profiling. (authors)

  5. Energy-filtered cold electron transport at room temperature.

    Science.gov (United States)

    Bhadrachalam, Pradeep; Subramanian, Ramkumar; Ray, Vishva; Ma, Liang-Chieh; Wang, Weichao; Kim, Jiyoung; Cho, Kyeongjae; Koh, Seong Jin

    2014-09-10

    Fermi-Dirac electron thermal excitation is an intrinsic phenomenon that limits functionality of various electron systems. Efforts to manipulate electron thermal excitation have been successful when the entire system is cooled to cryogenic temperatures, typically distribution corresponds to an effective electron temperature of ~45 K, can be transported throughout device components without external cooling. This is accomplished using a discrete level of a quantum well, which filters out thermally excited electrons and permits only energy-suppressed electrons to participate in electron transport. The quantum well (~2 nm of Cr2O3) is formed between source (Cr) and tunnelling barrier (SiO2) in a double-barrier-tunnelling-junction structure having a quantum dot as the central island. Cold electron transport is detected from extremely narrow differential conductance peaks in electron tunnelling through CdSe quantum dots, with full widths at half maximum of only ~15 mV at room temperature.

  6. Electron transfer across the polarized interface between water and a hydrophobic redox-active ionic liquid

    Czech Academy of Sciences Publication Activity Database

    Langmaier, Jan; Trojánek, Antonín; Samec, Zdeněk

    2010-01-01

    Roč. 12, č. 10 (2010), s. 1333-1335 ISSN 1388-2481 R&D Projects: GA MŠk ME08098; GA ČR GAP206/10/1231 Institutional research plan: CEZ:AV0Z40400503 Keywords : redox-active ionic liquid * membrane * cyclic voltammetry Subject RIV: CG - Electrochemistry Impact factor: 4.282, year: 2010

  7. Defect structure of yttria-stabilized zirconia and its influence on the ionic conductivity at elevated temperatures

    DEFF Research Database (Denmark)

    Goff, J.P.; Hayes, W.; Hull, S.

    1999-01-01

    The defect structure of cubic fluorite structured yttria-stabilized zirconia (ZrO2)(1-x)(Y2O3)(x) has been investigated over the composition range 0.100(3)less than or equal to x less than or equal to 0.241 (10) and temperatures T(K) up to 2780(10) K, using single-crystal specimens. Analysis of n......, we propose that the anomalous decrease in the ionic conductivity with increasing x is a consequence of the decreasing mobility of the isolated defects, possibly due to blockage by the increasing number of static aggregates....

  8. Metal coordination in the high-temperature leaching of roasted NdFeB magnets with the ionic liquid betainium bis(trifluoromethylsulfonyl)imide

    OpenAIRE

    Orefice, Martina; Binnemans, Koen; Vander Hoogerstraete, Tom

    2018-01-01

    Ionic liquids are largely used to leach metals from primary (ores) and secondary sources (end-of-life products). However, dry ionic liquids with a carboxylic function on the cation have not yet been used to leach metals at temperature above 100 °C and under atmospheric pressure. The ionic liquid betainium bis(trifluoromethylsulfonyl)imide, [Hbet][Tf2N], was used in the dry state to recover neodymium, dysprosium and cobalt from NdFeB magnets and NdFeB production scrap. The magnets and the scra...

  9. What Can we learn from Raman spectroscopy and model calculations on room temperature ionic liquids?

    OpenAIRE

    Berg, Rolf W.

    2006-01-01

    Traditionally ionic liquids involve inorganic hygroscopic substances that need to be contained under protective atmospheres, e.g. in sealed ampoules. Experimental methods to study the chemistry inside closed ampoules are limited, and one popular technique has been and still is Raman scattering because the laser light easily passes through the glassy ampoule wall. The method is of course equally valuable for non-hygroscopic substances and mixtures and “green liquids”. Raman spectra - though ch...

  10. Electrochemical behavior of Li2FeSiO4 with ionic liquids at elevated temperature

    Czech Academy of Sciences Publication Activity Database

    Nádherná, Martina; Dominko, R.; Hanzel, D.; Reiter, Jakub; Gabersček, M.

    2009-01-01

    Roč. 156, č. 7 (2009), A619-A626 ISSN 0013-4651 R&D Projects: GA MŠk LC523; GA AV ČR KJB400320701; GA MŠk(CZ) MEB090806 Institutional research plan: CEZ:AV0Z40320502 Keywords : ionic liquid * lithium -iont battery * lithium iron silicate Subject RIV: CG - Electrochemistry Impact factor: 2.241, year: 2009

  11. Ionic thermometers

    International Nuclear Information System (INIS)

    Strnad, M.

    1975-01-01

    An original method of temperature measurement based on conductivity changes near the phase transition point of ionic compounds and suitable for the range from 200 to 700 0 C according to the thermometric compound used, is given. By choosing between two approaches it is posible to evaluate either a discrete value of temperature or continuous measurement in a range to about 50 0 C below the phase transition point of thermometric compounds. The extreme nonlinearity of conductivity of the chosen group of ionic crystals used as well as the technical applications developed in the laboratories have not previously been published. The aim of the research is the application of this measuring method for temperature indication in nuclear reactors. Preliminary tests in radiation fields in an experimental reactor are yielding a real hope in this direction. (author)

  12. Energy and temperature fluctuations in the single electron box

    International Nuclear Information System (INIS)

    Berg, Tineke L van den; Brange, Fredrik; Samuelsson, Peter

    2015-01-01

    In mesoscopic and nanoscale systems at low temperatures, charge carriers are typically not in thermal equilibrium with the surrounding lattice. The resulting, non-equilibrium dynamics of electrons has only begun to be explored. Experimentally the time-dependence of the electron temperature (deviating from the lattice temperature) has been investigated in small metallic islands. Motivated by these experiments, we investigate theoretically the electronic energy and temperature fluctuations in a metallic island in the Coulomb blockade regime, tunnel coupled to an electronic reservoir, i.e. a single electron box. We show that electronic quantum tunnelling between the island and the reservoir, in the absence of any net charge or energy transport, induces fluctuations of the island electron temperature. The full distribution of the energy transfer as well as the island temperature is derived within the framework of full counting statistics. In particular, the low-frequency temperature fluctuations are analysed, fully accounting for charging effects and non-zero reservoir temperature. The experimental requirements for measuring the predicted temperature fluctuations are discussed. (paper)

  13. Electron temperature determination in LTE and non-LTE plasmas

    International Nuclear Information System (INIS)

    Eddy, T.L.

    1983-01-01

    This article discusses how most experimental investigations assume a type of ''thermal equilibrium'' in which the excited levels are assumed to be populated according to the electron kinetic temperature, in the determination of electron temperature in LTE and non-LTE plasmas. This is justified on the basis that electron collisions dominate the equilibration of adjacent excited levels as shown by Byron, Stabler and Boartz. The comparison of temperature values calculated by various common methods as a check for local thermodynamic equilibrium (LTDE) or local thermal equilibrium (LTE) of the upper excited levels and the free electrons has been shown to indicate the excitation temperature in all cases utilized. Thomas shows that the source function of the first excited level may be dominated by non-local radiation, which would usually result in a different population than local collisional excitation would provide. Ionization from upper levels is by collisional means. The result may yield different valued excitation and electron temperatures

  14. Electronically and ionically conductive porous material and method for manufacture of resin wafers therefrom

    Science.gov (United States)

    Lin, YuPo J [Naperville, IL; Henry, Michael P [Batavia, IL; Snyder, Seth W [Lincolnwood, IL

    2011-07-12

    An electrically and ionically conductive porous material including a thermoplastic binder and one or more of anion exchange moieties or cation exchange moieties or mixtures thereof and/or one or more of a protein capture resin and an electrically conductive material. The thermoplastic binder immobilizes the moieties with respect to each other but does not substantially coat the moieties and forms the electrically conductive porous material. A wafer of the material and a method of making the material and wafer are disclosed.

  15. Electronic microscopy study of miofilaments created artificially at low ionic power

    International Nuclear Information System (INIS)

    Corredor R, C.

    1995-07-01

    Artificial miofilaments created at low ionic power from miosin extracted from muscles tissues of Lepus cuniculus and of Homarus americanus showed morphological differences depending from the ionic power, pH and polymerization time. The dorsal muscle miosin of L Cuniculus created at low ionic power of 0,2 M KCl-PO 4 , polymerized into miofilaments of indefine length at a pH of 6,4. At a pH of 6,1 these miofilaments were shorter. The miosin of H americanus polymerized into miofilaments of sizeable length following a Gaussian distribution with a modal value dependant on the time of polymerization. The miosin from the abdominal flexor muscle had a greater modal length than the miofilaments drawn from the miosin of the 'tenaza' muscle (Fig. 1). Two types of electrodensity 'coloration' are observed: the positive coloration is characterized by a quasi homogeneous or continuous distribution of Uranilo acetate on the miofibrilla and its surroundings showing few muscular details of the miofibrillas. The negative coloration, characterized by a distribution around the miofibrillas enabled a better observation of morphological details (Fig. 2). These two types of coloration or electrodensity reveal hydrophobic or

  16. Crystal growth and electronic structure of low-temperature phase SrMgF{sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Atuchin, Victor V. [Laboratory of Optical Materials and Structures, Institute of Semiconductor Physics, SB RAS, Novosibirsk 630090 (Russian Federation); Functional Electronics Laboratory, Tomsk State University, Tomsk 634050 (Russian Federation); Laboratory of Semiconductor and Dielectric Materials, Novosibirsk State University, Novosibirsk 630090 (Russian Federation); Goloshumova, Alina A. [Laboratory of Crystal Growth, Institute of Geology and Mineralogy, SB RAS, Novosibirsk 630090 (Russian Federation); Isaenko, Ludmila I. [Laboratory of Semiconductor and Dielectric Materials, Novosibirsk State University, Novosibirsk 630090 (Russian Federation); Laboratory of Crystal Growth, Institute of Geology and Mineralogy, SB RAS, Novosibirsk 630090 (Russian Federation); Jiang, Xingxing [BCCRD, Key Laboratory of Functional Crystals and Laser Technology, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Lobanov, Sergey I. [Laboratory of Crystal Growth, Institute of Geology and Mineralogy, SB RAS, Novosibirsk 630090 (Russian Federation); Zhang, Zhaoming [Australian Nuclear Science & Technology Organisation, Lucas Heights, NSW 2234 (Australia); Lin, Zheshuai, E-mail: zslin@mail.ipc.ac.cn [BCCRD, Key Laboratory of Functional Crystals and Laser Technology, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190 (China)

    2016-04-15

    Using the vertical Bridgman method, the single crystal of low temperature phase SrMgF{sub 4} is obtained. The crystal is in a very good optical quality with the size of 10×7×5 mm{sup 3}. Detailed photoemission spectra of the element core levels are determined by a monochromatic AlKa (1486.6 eV) X-ray source. Moreover, the first-principles calculations are performed to investigate the electronic structure of SrMgF{sub 4}. A good agreement between experimental and calculated results is achieved. It is demonstrated that almost all the electronic orbitals are strongly localized and the hybridization with the others is very small, but the Mg–F bonds covalency is relatively stronger than that of Sr–F bonds. - Graphical abstract: Large size of low-temperature phase SrMgF{sub 4} crystal was obtained (right) and its electronic structure was investigated by X-ray photoelectron spectroscopy and first-principles calculation (left). - Highlights: • Large size single crystal of low-temperature phase SrMgF{sub 4} is obtained. • Electronic structure of SrMgF{sub 4} is measured by X-ray photoelectron spectroscopy. • Partial densities of states are determined by first-principles calculation. • Good agreement between experimental and calculated results is achieved. • Strong ionic characteristics of chemical bonds are exhibited in SrMgF{sub 4}.

  17. Ionic and electronic dark decay of holograms in LiNbO3:Fe crystals

    International Nuclear Information System (INIS)

    Yang, Yunping; Nee, Ingo; Buse, Karsten; Psaltis, Demetri

    2001-01-01

    The lifetimes of nonfixed holograms in LiNbO 3 :Fe crystals with doping levels of 0.05, 0.138, and 0.25 wt% Fe 2 O 3 have been measured in the temperature range from 30 to 180 degree C. The time constants of the dark decay of holograms stored in crystals with doping levels of 0.05 and 0.25 wt% Fe 2 O 3 obey an Arrhenius-type dependence on absolute temperature T, but yield two activation energies: 1.0 and 0.28 eV, respectively. For these crystals, two different dark decay mechanisms are prevailing, one of which is identified as proton compensation and the other is due to electron tunneling between sites of Fe 2+ and Fe 3+ . The dark decay of holograms stored in crystals with the doping level of 0.138 wt% Fe 2 O 3 is the result of a combination of both effects. [copyright] 2001 American Institute of Physics

  18. IMIDAZOLE-BASED IONIC LIQUIDS FOR USE IN POLYMER ELECTROLYTE MEMBRANE FUEL CELLS: EFFECT OF ELECTRON-WITHDRAWING AND ELECTRON-DONATING SUBSTITUENTS

    Energy Technology Data Exchange (ETDEWEB)

    Chang, E.; Fu, Y.; Kerr, J.

    2009-01-01

    Current polymer electrolyte membrane fuel cells (PEMFCs) require humidifi cation for acceptable proton conductivity. Development of a novel polymer that is conductive without a water-based proton carrier is desirable for use in automobiles. Imidazole (Im) is a possible replacement for water as a proton solvent; Im can be tethered to the polymer structure by means of covalent bonds, thereby providing a solid state proton conducting membrane where the solvating groups do not leach out of the fuel cell. These covalent bonds can alter the electron availability of the Im molecule. This study investigates the effects of electron-withdrawing and electron-donating substituents on the conductivity of Im complexed with methanesulfonic acid (MSA) in the form of ionic liquids. Due to the changes in the electronegativity of nitrogen, it is expected that 2-phenylimidazole (2-PhIm, electron-withdrawing) will exhibit increased conductivity compared to Im, while 2-methylimidazole (2-MeIm, electron-donating) will exhibit decreased conductivity. Three sets of ionic liquids were prepared at defi ned molar ratios: Im-MSA, 2-PhIm-MSA, and 2-MeIm- MSA. Differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and 1H-NMR were used to characterize each complex. Impedance analysis was used to determine the conductivity of each complex. Both the 2-PhIm-MSA and 2-MeIm-MSA ionic liquids were found to be less conductive than the Im-MSA complex at base-rich compositions, but more conductive at acid-rich compositions. 1H-NMR data shows a downfi eld shift of the proton on nitrogen in 2-PhIm compared to Im, suggesting that other factors may diminish the electronic effects of the electron withdrawing group at base-rich compositions. Further studies examining these effects may well result in increased conductivity for Im-based complexes. Understanding the conductive properties of Im-derivatives due to electronic effects will help facilitate the development of a new electrolyte

  19. First high-temperature electronics products survey 2005.

    Energy Technology Data Exchange (ETDEWEB)

    Normann, Randy Allen

    2006-04-01

    On April 4-5, 2005, a High-Temperature Electronics Products Workshop was held. This workshop engaged a number of governmental and private industry organizations sharing a common interest in the development of commercially available, high-temperature electronics. One of the outcomes of this meeting was an agreement to conduct an industry survey of high-temperature applications. This report covers the basic results of this survey.

  20. Effect of Structure on Transport Properties (Viscosity, Ionic Conductivity, and Self-Diffusion Coefficient) of Aprotic Heterocyclic Anion (AHA) Room-Temperature Ionic Liquids. 1. Variation of Anionic Species.

    Science.gov (United States)

    Sun, Liyuan; Morales-Collazo, Oscar; Xia, Han; Brennecke, Joan F

    2015-12-03

    A series of room temperature ionic liquids (RTILs) based on 1-ethyl-3-methylimidazolium ([emim](+)) with different aprotic heterocyclic anions (AHAs) were synthesized and characterized as potential electrolyte candidates for lithium ion batteries. The density and transport properties of these ILs were measured over the temperature range between 283.15 and 343.15 K at ambient pressure. The temperature dependence of the transport properties (viscosity, ionic conductivity, self-diffusion coefficient, and molar conductivity) is fit well by the Vogel-Fulcher-Tamman (VFT) equation. The best-fit VFT parameters, as well as linear fits to the density, are reported. The ionicity of these ILs was quantified by the ratio of the molar conductivity obtained from the ionic conductivity and molar concentration to that calculated from the self-diffusion coefficients using the Nernst-Einstein equation. The results of this study, which is based on ILs composed of both a planar cation and planar anions, show that many of the [emim][AHA] ILs exhibit very good conductivity for their viscosities and provide insight into the design of ILs with enhanced dynamics that may be suitable for electrolyte applications.

  1. TiO2 coated Si nanowire electrodes for electrochemical double layer capacitors in room temperature ionic liquid

    International Nuclear Information System (INIS)

    Konstantinou, F; Shougee, A; Albrecht, T; Fobelets, K

    2017-01-01

    Three TiO 2 deposition processes are used to coat the surface of Si nanowire array electrodes for electrochemical double layer capacitors in room temperature ionic liquid [Bmim][NTF 2 ]. The fabrication processes are based on wet chemistry only and temperature treatments are kept below 450 °C. Successful TiO 2 coatings are found to be those that are carried out at low pressure and with low TiO 2 coverage to avoid nanowires breakage. The best TiO 2 coated Si nanowire array electrode in [Bmim][NTF 2 ] showed energy densities of 0.9 Wh·kg −1 and power densities of 2.2 kW·kg −1 with a nanowire length of ∼10 µ m. (paper)

  2. Effect of Temperature on the Physico-Chemical Properties of a Room Temperature Ionic Liquid (1-Methyl-3-pentylimidazolium Hexafluorophosphate) with Polyethylene Glycol Oligomer

    Science.gov (United States)

    Wu, Tzi-Yi; Chen, Bor-Kuan; Hao, Lin; Peng, Yu-Chun; Sun, I-Wen

    2011-01-01

    A systematic study of the effect of composition on the thermo-physical properties of the binary mixtures of 1-methyl-3-pentyl imidazolium hexafluorophosphate [MPI][PF6] with poly(ethylene glycol) (PEG) [Mw = 400] is presented. The excess molar volume, refractive index deviation, viscosity deviation, and surface tension deviation values were calculated from these experimental density, ρ, refractive index, n, viscosity, η, and surface tension, γ, over the whole concentration range, respectively. The excess molar volumes are negative and continue to become increasingly negative with increasing temperature; whereas the viscosity and surface tension deviation are negative and become less negative with increasing temperature. The surface thermodynamic functions, such as surface entropy, enthalpy, as well as standard molar entropy, Parachor, and molar enthalpy of vaporization for pure ionic liquid, have been derived from the temperature dependence of the surface tension values. PMID:21731460

  3. Effect of Temperature on the Physico-Chemical Properties of a Room Temperature Ionic Liquid (1-Methyl-3-pentylimidazolium Hexafluorophosphate with Polyethylene Glycol Oligomer

    Directory of Open Access Journals (Sweden)

    Lin Hao

    2011-04-01

    Full Text Available A systematic study of the effect of composition on the thermo-physical properties of the binary mixtures of 1-methyl-3-pentyl imidazolium hexafluorophosphate [MPI][PF6] with poly(ethylene glycol (PEG [Mw = 400] is presented. The excess molar volume, refractive index deviation, viscosity deviation, and surface tension deviation values were calculated from these experimental density, ρ, refractive index, n, viscosity, η, and surface tension, γ, over the whole concentration range, respectively. The excess molar volumes are negative and continue to become increasingly negative with increasing temperature; whereas the viscosity and surface tension deviation are negative and become less negative with increasing temperature. The surface thermodynamic functions, such as surface entropy, enthalpy, as well as standard molar entropy, Parachor, and molar enthalpy of vaporization for pure ionic liquid, have been derived from the temperature dependence of the surface tension values.

  4. Electrochemical measurements of mass transfer in RTILs (Room Temperature Ionic Liquids) medium under low frequency ultrasound irradiation; Mesures electrochimiques de transfert de matiere en milieu RTIL's (Room Temperature Ionic Liquids) sous irradiation ultrasonore basse frequence

    Energy Technology Data Exchange (ETDEWEB)

    Costa, C.; Hihn, J.Y.; Rebetez, M.; Doche, M.L. [Universite de Franche Comte - IUT Dept. Chimie, Institut UTINAM-UMR CNRS 6213, 25 - Montbeliard (France); Costa, C.; Bisel, I. [CEA Valrho, Dir. de l' Energie Nucleaire (DEN/DRCP/SCPS/LPCP), 30 - Marcoule (France); Moisy, Ph. [CEA Valrho, Dir. de l' Energie Nucleaire (DEN/DRCP/SCPS/LCA), 30 - Marcoule (France)

    2007-07-01

    The aim of this work is to measure the influence of ultrasounds on the mass transfer at the electrode. The electro diffusional method which consists to measure the limit diffusion current on the polarization curve i=f(E) of a reversible couple in diluted solution in the electrolyte. The used couple changes with the electrolytic medium: potassium ferro/ferricyanide in water, ferrocene/ferricinium for acetonitrile and for the ionic liquid 1-butyl-3-methyl-imidazolium bis(tri-fluoro-methyl-sulfonyl)imide [BuMIm][CF{sub 3}SO{sub 2}){sub 2}N]). The limit diffusion currents are converted into mass transfer coefficients and then into a dimensional Sherwood numbers to allow an easier comparison of the results between the different research teams participating to this study. Recent tests, carried out in partner laboratories (LCMI-UFC, LPCP-CEA and LCA-CEA) have demonstrated the interest of the use of power ultrasounds in Room Temperature Ionic Liquids (RTILs) but revealed too a lot of experimental difficulties. Nevertheless, it appears that the ultrasounds are an aging mode particularly adapted to the RTILs because the mass transfer to the electrode is there 5 times more efficient than in presence of an electrode turning at 4500 tr.min{sup -1}, while limiting their re-hydration. (O.M.)

  5. Martian Electron Temperatures in the Sub Solar Region.

    Science.gov (United States)

    Fowler, C. M.; Peterson, W. K.; Andersson, L.; Thiemann, E.; Mayyasi, M.; Yelle, R. V.; Benna, M.; Espley, J. R.

    2017-12-01

    Observations from Viking, and MAVEN have shown that the observed ionospheric electron temperatures are systematically higher than those predicted by many models. Because electron temperature is a balance between heating, cooling, and heat transport, we systematically compare the magnitude of electron heating from photoelectrons, electron cooling and heat transport, as a function of altitude within 30 degrees of the sub solar point. MAVEN observations of electron temperature and density, EUV irradiance, neutral and ion composition are used to evaluate terms in the heat equation following the framework of Matta et al. (Icarus, 2014, doi:10.1016/j.icarus.2013.09.006). Our analysis is restricted to inbound orbits where the magnetic field is within 30 degrees of horizontal. MAVEN sampled the sub solar region in May 2015 and again in May 2017, in near northern spring equinoctial conditions. Solar activity was higher and the spacecraft sampled altitudes down to 120 km in 2015, compared to 160 km in 2017. We find that between 160 and 200 km the Maven electron temperatures are in thermal equilibrium, in the sub solar region, on field lines inclined less than 30 degrees to the horizontal. Above 200km the data suggest that heating from other sources, such as wave heating are significant. Below 160 km some of the discrepancy comes from measurement limitations. This is because the MAVEN instrument cannot resolve the lowest electron temperatures, and because some cooling rates scale as the difference between the electron and neutral temperatures.

  6. Anomalous plasma transport due to electron temperature gradient instability

    International Nuclear Information System (INIS)

    Tokuda, Sinji; Ito, Hiroshi; Kamimura, Tetsuo.

    1979-01-01

    The collisionless drift wave instability driven by an electron temperature inhomogeneity (electron temperature gradient instability) and the enhanced transport processes associated with it are studied using a two-and-a-half dimensional particle simulation code. The simulation results show that quasilinear diffusion in phase space is an important mechanism for the saturation of the electron temperature gradient instability. Also, the instability yields particle fluxes toward the hot plasma regions. The heat conductivity of the electron temperature perpendicular to the magnetic field, T sub(e'), is not reduced by magnetic shear but remains high, whereas the heat conductivity of the parallel temperature, T sub(e''), is effectively reduced, and the instability stabilized. (author)

  7. MICROWAVE NOISE MEASUREMENT OF ELECTRON TEMPERATURES IN AFTERGLOW PLASMAS

    Energy Technology Data Exchange (ETDEWEB)

    Leiby, Jr., C. C.; McBee, W. D.

    1963-10-15

    Transient electron temperatures in afterglow plasmas were determined for He (5 and 10 torr), Ne, and Ne plus or minus 5% Ar (2.4 and 24 torr) by combining measurements of plasma microwave noise power, and plasma reflectivity and absorptivity. Use of a low-noise parametric preamplifier permitted continuous detection during the afterglow of noise power at 5.5 Bc in a 1 Mc bandwidth. Electron temperature decays were a function of pressure and gas but were slower than predicted by electron energy loss mechanisms. The addition of argon altered the electron density decay in the neon afterglow but the electron temperature decay was not appreciably changed. Resonances in detected noise power vs time in the afterglow were observed for two of the three plasma waveguide geometries studied. These resonances correlate with observed resonances in absorptivity and occur over the same range of electron densities for a given geometry independent of gas type and pressure. (auth)

  8. Potential Formation in Front of an Electron Emitting Electrode in a Two-Electron Temperature Plasma

    International Nuclear Information System (INIS)

    Gyergyek, T.; Cercek, M.; Erzen, D.

    2003-01-01

    Plasma potential formation in the pre-sheath region of a floating electron emitting electrode (collector) is studied theoretically in a two-electron-temperature plasma using a static kinetic plasma-sheath model. Dependence of the collector floating potential, the plasma potential in the pre-sheath region, and the critical emission coefficient on the hot electron density and temperature is calculated. It is found that for high hot to cool electron temperature ratio a double layer like solutions exist in a certain range of hot to cool electron densities

  9. Electron Density and Temperature Measurements, and Abundance ...

    Indian Academy of Sciences (India)

    tribpo

    tics—emission lines. Dwivedi, Curdt & Wilhelm (1997, 1999a) carried out an observing sequence based on a theoretical study by Dwivedi & Mohan (1995), with intercombination/forbidden. Ne VI and Mg VI lines, which are formed at essentially the same temperature. (4 × 105 K), according to Arnaud & Rothenflug (1985).

  10. Pyrrolidinium FSI and TFSI-Based Polymerized Ionic Liquids as Electrolytes for High-Temperature Lithium-Ion Batteries

    Directory of Open Access Journals (Sweden)

    Manfred Kerner

    2018-02-01

    Full Text Available Promising electrochemical and dynamical properties, as well as high thermal stability, have been the driving forces behind application of ionic liquids (ILs and polymerized ionic liquids (PILs as electrolytes for high-temperature lithium-ion batteries (HT-LIBs. Here, several ternary lithium-salt/IL/PIL electrolytes (PILel have been investigated for synergies of having both FSI and TFSI anions present, primarily in terms of physico-chemical properties, for unique application in HT-LIBs operating at 80 °C. All of the electrolytes tested have low Tg and are thermally stable ≥100 °C, and with TFSI as the exclusive anion the electrolytes (set A have higher thermal stabilities ≥125 °C. Ionic conductivities are in the range of 1 mS/cm at 100 °C and slightly higher for set A PILel, which, however, have lower oxidation stabilities than set B PILel with both FSI and TFSI anions present: 3.4–3.7 V vs. 4.2 V. The evolution of the interfacial resistance increases for all PILel during the first 40 h, but are much lower for set B PILel and generally decrease with increasing Li-salt content. The higher interfacial resistances only influence the cycling performance at high C-rates (1 C, where set B PILel with high Li-salt content performs better, while the discharge capacities at the 0.1 C rate are comparable. Long-term cycling at 0.5 C, however, shows stable discharge capacities for 100 cycles, with the exception of the set B PILel with high Li-salt content. Altogether, the presence of both FSI and TFSI anions in the PILel results in lower ionic conductivities and decreased thermal stabilities, but also higher oxidation stabilities and reduced interfacial resistances and, in total, result in an improved rate capability, but compromised long-term capacity retention. Overall, these electrolytes open for novel designs of HT-LIBs.

  11. Kinetics of the oxidation of hydrogen sulfite by hydrogen peroxide in aqueous solution:. ionic strength effects and temperature dependence

    Science.gov (United States)

    Maaß, Frank; Elias, Horst; Wannowius, Klaus J.

    Conductometry was used to study the kinetics of the oxidation of hydrogen sulfite, HSO -3, by hydrogen peroxide in aqueous non-buffered solution at the low concentration level of 10 -5-10 -6 M, typically found in cloud water. The kinetic data confirm that the rate law reported for the pH range 3-6 at higher concentration levels, rate= kH·[H +]·[HSO -3]·[H 2O 2], is valid at the low concentration level and at low ionic strength Ic. At 298 K and Ic=1.5×10 -4 M, third-order rate constant kH was found to be kH=(9.1±0.5)×10 7 M -2 s -1. The temperature dependence of kH led to an activation energy of Ea=29.7±0.9 kJ mol -1. The effect of the ionic strength (adjusted with NaCl) on rate constant kH was studied in the range Ic=2×10 -4-5.0 M at pH=4.5-5.2 by conductometry and stopped-flow spectrophotometry. The dependence of kH on Ic can be described with a semi-empirical relationship, which is useful for the purpose of comparison and extrapolation. The kinetic data obtained are critically compared with those reported earlier.

  12. Room-Temperature Ionic Liquids and Biomembranes: Setting the Stage for Applications in Pharmacology, Biomedicine, and Bionanotechnology.

    Science.gov (United States)

    Benedetto, Antonio; Ballone, Pietro

    2018-03-21

    Empirical evidence and conceptual elaboration reveal and rationalize the remarkable affinity of organic ionic liquids for biomembranes. Cations of the so-called room-temperature ionic liquids (RTILs), in particular, are readily absorbed into the lipid fraction of biomembranes, causing a variety of observable biological effects, including generic cytotoxicity, broad antibacterial potential, and anticancer activity. Chemical physics analysis of model systems made of phospholipid bilayers, RTIL ions, and water confirm and partially explain this evidence, quantifying the mild destabilizing effect of RTILs on the structural, dynamic, and thermodynamic properties of lipids in biomembranes. Our Feature Article presents a brief introduction to these systems and to their roles in biophysics and biotechnology, summarizing recent experimental and computational results on their properties. More importantly, it highlights the many developments in pharmacology, biomedicine, and bionanotechnology expected from the current research effort on this topic. To anticipate future developments, we speculate on (i) potential applications of (magnetic) RTILs to affect and control the rheology of cells and biological tissues, of great relevance for diagnostics and (ii) the use of RTILs to improve the durability, reliability, and output of biomimetic photovoltaic devices.

  13. Divertor materials for ITER - Tungsten and carbon/carbon composite behavior under coupled ionic irradiation and high temperature

    Energy Technology Data Exchange (ETDEWEB)

    Raunier, S.; Balat-Pichelin, M.; Sans, J.L.; Hernandez, D. [Laboratoire PROMES-CNRS, Laboratoire Procedes, Materiaux et Energie Solaire, 7 rue du Four Solaire, 66120 Font-Romeu Odeillo (France)

    2007-07-01

    Full text of publication follows: In the frame of the International Thermonuclear Experimental Reactor ITER, the physical-chemical characterization of plasma-facing components (divertor and structural materials) is essential because they are subjected to simultaneous high thermal and ionic fluxes. In this paper, an experimental and theoretical study of the physical-chemical behavior of carbon/carbon composite and tungsten (materials for ITER divertor) under extreme conditions is performed. The simulation of the interaction of hydrogen ions with the material, the theoretical study of physical erosion (TRIM and TRIDYN codes) and the chemical erosion (GEMINI code) are carried out. The conditions of nominal or accidental mode that can occur during the operation of the reactor (high temperature 1300 - 2500 K, high vacuum, H{sup +} ionic flux with different energies) are experimentally simulated. In this work, we have studied the material degradation, the mass loss kinetics, the characterization of the emitted neutral and charged species of heated and both heated and irradiated materials, and the determination of the thermo-radiative properties versus time. This study, done in collaboration with CEA Cadarache, is realized using the MEDIASE experimental device (Moyen d'Essai et de Diagnostic en Ambiance Solaire Extreme) located at the focus of the 1000 kW solar furnace of PROMES-CNRS laboratory in Odeillo. Material characterization pre- and post-processing is performed with classical techniques as SEM, XRD and XPS and also by measuring the BRDF (Bidirectional Reflectivity Diffusion Function). (authors)

  14. Divertor materials for ITER - Tungsten and carbon/carbon composite behavior under coupled ionic irradiation and high temperature

    International Nuclear Information System (INIS)

    Raunier, S.; Balat-Pichelin, M.; Sans, J.L.; Hernandez, D.

    2007-01-01

    Full text of publication follows: In the frame of the International Thermonuclear Experimental Reactor ITER, the physical-chemical characterization of plasma-facing components (divertor and structural materials) is essential because they are subjected to simultaneous high thermal and ionic fluxes. In this paper, an experimental and theoretical study of the physical-chemical behavior of carbon/carbon composite and tungsten (materials for ITER divertor) under extreme conditions is performed. The simulation of the interaction of hydrogen ions with the material, the theoretical study of physical erosion (TRIM and TRIDYN codes) and the chemical erosion (GEMINI code) are carried out. The conditions of nominal or accidental mode that can occur during the operation of the reactor (high temperature 1300 - 2500 K, high vacuum, H + ionic flux with different energies) are experimentally simulated. In this work, we have studied the material degradation, the mass loss kinetics, the characterization of the emitted neutral and charged species of heated and both heated and irradiated materials, and the determination of the thermo-radiative properties versus time. This study, done in collaboration with CEA Cadarache, is realized using the MEDIASE experimental device (Moyen d'Essai et de Diagnostic en Ambiance Solaire Extreme) located at the focus of the 1000 kW solar furnace of PROMES-CNRS laboratory in Odeillo. Material characterization pre- and post-processing is performed with classical techniques as SEM, XRD and XPS and also by measuring the BRDF (Bidirectional Reflectivity Diffusion Function). (authors)

  15. Observation of electron plasma waves in plasma of two-temperature electrons

    International Nuclear Information System (INIS)

    Ikezawa, Shunjiro; Nakamura, Yoshiharu.

    1981-01-01

    Propagation of electron plasma waves in a large and unmagnetized plasma containing two Maxwellian distributions of electrons is studied experimentally. Two kinds of plasma sources which supply electrons of different temperature are used. The temperature ratio is about 3 and the density ratio of hot to cool electrons is varied from 0 to 0.5. A small contamination of hot electrons enhances the Landau damping of the principal mode known as the Bohm-Gross mode. When the density of hot electrons is larger than about 0.2, two modes are observed. The results agree with theoretical dispersion relations when excitation efficiencies of the modes are considered. (author)

  16. Thermoluminescence in KBr:D electron irradiated at room temperature

    International Nuclear Information System (INIS)

    Paredes Campoy, J.C.; Lopez Carranza, E.

    1991-07-01

    The thermoluminescence of KBr:D samples electron irradiated at room temperature after thermal annealing at 673 K for 1 hour have been studied in the temperature range 360-730 K. The experimental TL-curve was discomposed by computer analysis in seven overlapping TL peaks, giving for them the order of the kinetics of thermal stimulation, the activation energy, the frequency factor, the relative values of the electronic concentration in traps at the initial heating temperature and the temperature at the maximum of the peak. (author). 18 refs, 1 fig., 3 tabs

  17. Electron temperature fluctuation in the HT-7 tokamak plasma observed by electron cyclotron emission imaging

    International Nuclear Information System (INIS)

    Xiao-Yuan, Xu; Jun, Wang; Yi, Yu; Yi-Zhi, Wen; Chang-Xuan, Yu; Wan-Dong, Liu; Bao-Nian, Wan; Xiang, Gao; Luhmann, N. C.; Domier, C. W.; Wang, Jian; Xia, Z. G.; Shen, Zuowei

    2009-01-01

    The fluctuation of the electron temperature has been measured by using the electron cyclotron emission imaging in the Hefei Tokamak-7 (HT-7) plasma. The electron temperature fluctuation with a broadband spectrum shows that it propagates in the electron diamagnetic drift direction, and the mean poloidal wave-number k-bar θ is calculated to be about 1.58 cm −1 , or k-bar θρ s thickapprox 0.34. It indicates that the fluctuation should come from the electron drift wave turbulence. The linear global scaling of the electron temperature fluctuation with the gradient of electron temperature is consistent with the mixing length scale qualitatively. Evolution of spectrum of the fluctuation during the sawtooth oscillation phases is investigated, and the fluctuation is found to increase with the gradient of electron temperature increasing during most phases of the sawtooth oscillation. The results indicate that the electron temperature gradient is probably the driver of the fluctuation enhancement. The steady heat flux driven by electron temperature fluctuation is estimated and compared with the results from power balance estimation. (fluids, plasmas and electric discharges)

  18. Room temperature deposition of ZnSe thin films by successive ionic layer adsorption and reaction (SILAR) method

    International Nuclear Information System (INIS)

    Kale, R.B.; Lokhande, C.D.

    2004-01-01

    The zinc selenide (ZnSe) thin films are deposited onto glass substrate using relatively simple and inexpensive successive ionic layer adsorption and reaction (SILAR) method. The films are deposited using zinc acetate sodium selenosulphate precursors. The concentration, pH, immersion and rinsing times and number of immersion cycles have been optimized to obtain good quality ZnSe thin films. The X-ray diffraction (XRD) study and scanning electron microscopy (SEM) studies reveals nanocrystalline nature alongwith some amorphous phase present in ZnSe thin films. Energy dispersive X-ray (EDAX) analysis shows that the films are Se deficient. From optical absorption data, the optical band gap 'E g ' for as-deposited thin film was found to be 2.8 eV and electrical resistivity in the order of 10 7 Ω cm

  19. Liquid–liquid extraction of Pu(IV), U(VI) and Am(III) using malonamide in room temperature ionic liquid as diluent

    International Nuclear Information System (INIS)

    Rout, Alok; Venkatesan, K.A.; Srinivasan, T.G.; Vasudeva Rao, P.R.

    2012-01-01

    Highlights: ► Extraction of actinides using malonamide in room temperature ionic liquid. ► High distribution ratios of actinides in room temperature ionic liquid. ► Ion exchange mechanism. ► Stoichiometry of extraction. ► High separation factors of U(VI) and Pu(IV) over Am(III) and fission products. - Abstract: The extraction behavior of U(VI), Pu(IV) and Am(III) from nitric acid medium by a solution of N,N-dimethyl-N,N-dioctyl-2-(2-hexyloxyethyl)malonamide (DMDOHEMA) in the room temperature ionic liquid, 1–butyl–3–methylimidazolium bis(trifluoromethanesulfonyl)imide (C 4 mimNTf 2 ), was studied. The distribution ratio of these actinides in DMDOHEMA/C 4 mimNTf 2 was measured as a function of various parameters such as the concentration of nitric acid, DMDOHEMA, NTf 2 − , alkyl chain length of ionic liquid. The extraction of actinides in the absence of DMDOHEMA was insignificant and the distribution ratio achieved in conjunction with C 4 mimNTf 2 , was remarkable. The separation factor of U(VI) and Pu(IV) achieved with the use of DMDOHEMA, ionic liquid was compared with Am(III) and other fission products. The stoichiometry of the metal-solvate was determined to be 1:2 for U(VI) and Pu(IV) and 1:3 for Am(III).

  20. Electronic Monitoring Of Storage And Transport Temperatures Of ...

    African Journals Online (AJOL)

    Electronic Monitoring Of Storage And Transport Temperatures Of Thermostable Newcastle ... 22) were monitored during storage and transport from vaccine production laboratory in Temeke, Dar es ... EMAIL FULL TEXT EMAIL FULL TEXT

  1. Electronic Modeling and Design for Extreme Temperatures, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose to develop electronics for operation at temperatures that range from -230oC to +130oC. This new technology will minimize the requirements for external...

  2. New Temperature-Insensitive Electronically-Tunable Grounded Capacitor Simulator

    OpenAIRE

    Abuelma'atti, Muhammad Taher; Khan, Muhammad Haroon

    1996-01-01

    A new circuit for simulating a grounded capacitor is presented. The circuit uses one operationalamplifier (OA), three operational-transconductance amplifiers (OTAs), and one capacitor. The realized capacitor is temperature-insensitive and electronically tunable. Experimental results are included.

  3. Room-Temperature Synthesis of Transition Metal Clusters and Main Group Polycations from Ionic Liquids

    OpenAIRE

    Ahmed, Ejaz

    2011-01-01

    Main group polycations and transition metal clusters had traditionally been synthesized via high-temperature routes by performing reactions in melts or by CTR, at room-temperature or lower temperature by using so-called superacid solvents, and at room-temperature in benzene–GaX3 media. Considering the major problems associated with higher temperature routes (e.g. long annealing time, risk of product decomposition, and low yield) and taking into account the toxicity of benzene and liquid SO2 i...

  4. Plutonium Elastic Moduli, Electron Localization, and Temperature

    International Nuclear Information System (INIS)

    Migliori, Albert; Mihut-Stroe, Izabella; Betts, Jon B.

    2008-01-01

    In almost all materials, compression is accompanied naturally by stiffening. Even in materials with zero or negative thermal expansion, where warming is accompanied by volume contraction it is the volume change that primarily controls elastic stiffness. Not so in the metal plutonium. In plutonium, alloying with gallium can change the sign of thermal expansion, but for the positive thermal- expansion monoclinic phase as well as the face-centered-cubic phase with either sign of thermal expansion, and the orthorhombic phase, recent measurements of elastic moduli show soften on warming by an order of magnitude more than expected, the shear and compressional moduli track, and volume seems irrelevant. These effects point toward a novel mechanism for electron localization, and have important implication for the pressure dependence of the bulk compressibility. (authors)

  5. 2-D Imaging of Electron Temperature in Tokamak Plasmas

    International Nuclear Information System (INIS)

    Munsat, T.; Mazzucato, E.; Park, H.; Domier, C.W.; Johnson, M.; Luhmann, N.C. Jr.; Wang, J.; Xia, Z.; Classen, I.G.J.; Donne, A.J.H.; Pol, M.J. van de

    2004-01-01

    By taking advantage of recent developments in millimeter wave imaging technology, an Electron Cyclotron Emission Imaging (ECEI) instrument, capable of simultaneously measuring 128 channels of localized electron temperature over a 2-D map in the poloidal plane, has been developed for the TEXTOR tokamak. Data from the new instrument, detailing the MHD activity associated with a sawtooth crash, is presented

  6. Synthesis of POSS-based ionic conductors with low glass transition temperatures for efficient solid-state dye-sensitized solar cells.

    Science.gov (United States)

    Zhang, Wei; Wang, Zhong-Sheng

    2014-07-09

    Replacing liquid-state electrolytes with solid-state electrolytes has been proven to be an effective way to improve the durability of dye-sensitized solar cells (DSSCs). We report herein the synthesis of amorphous ionic conductors based on polyhedral oligomeric silsesquioxane (POSS) with low glass transition temperatures for solid-state DSSCs. As the ionic conductor is amorphous and in the elastomeric state at the operating temperature of DSSCs, good pore filling in the TiO2 film and good interfacial contact between the solid-state electrolyte and the TiO2 film can be guaranteed. When the POSS-based ionic conductor containing an allyl group is doped with only iodine as the solid-state electrolyte without any other additives, power conversion efficiency of 6.29% has been achieved with good long-term stability under one-sun soaking for 1000 h.

  7. Hydrogen Bonding, (1)H NMR, and Molecular Electron Density Topographical Characteristics of Ionic Liquids Based on Amino Acid Cations and Their Ester Derivatives.

    Science.gov (United States)

    Rao, Soniya S; Bejoy, Namitha Brijit; Gejji, Shridhar P

    2015-08-13

    Amino acid ionic liquids (AAILs) have attracted significant attention in the recent literature owing to their ubiquitous applications in diversifying areas of modern chemistry, materials science, and biosciences. The present work focuses on unraveling the molecular interactions underlying AAILs. Electronic structures of ion pairs consisting of amino acid cations ([AA(+)], AA = Gly, Ala, Val, Leu, Ile, Pro, Ser, Thr) and their ester substituted derivatives [AAE(+)] interacting with nitrate anion [NO3(-)] have been obtained from the dispersion corrected M06-2x density functional theory. The formation of ion pair is accompanied by the transfer of proton from quaternary nitrogen to anion facilitated via hydrogen bonding. The [Ile], [Pro], [Ser], and [Thr] and their esters reveal relatively strong inter- as well as intramolecular hydrogen-bonding interactions. Consequently, the hierarchy in binding energies of [AA][NO3] ion pairs and their ester analogues turns out to be [Gly] > [Ala] > [Ser] ∼ [Val] ∼ [Ile] > [Leu] ∼ [Thr] > [Pro]. The work underlines how the interplay of intra- as well as intermolecular hydrogen-bonding interactions in [AA]- and [AAE]-based ILs manifest in their infrared and (1)H NMR spectra. Substitution of -OCH3 functional group in [AA][NO3] ILs lowers the melting point attributed to weaker hydrogen-bonding interactions, making them suitable for room temperature applications. As opposed to gas phase structures, the presence of solvent (DMSO) does not bring about any proton transfer in the ion pairs or their ester analogues. Calculated (1)H NMR chemical shifts of the solvated structures agree well with those from experiment. Correlations of decomposition temperatures in [AA]- and [AAE]-based ILs with binding energies and electron densities at the bond critical point(s) in molecular electron density topography, have been established.

  8. High-Temperature Electronics: A Role for Wide Bandgap Semiconductors?

    Science.gov (United States)

    Neudeck, Philip G.; Okojie, Robert S.; Chen, Liang-Yu

    2002-01-01

    It is increasingly recognized that semiconductor based electronics that can function at ambient temperatures higher than 150 C without external cooling could greatly benefit a variety of important applications, especially-in the automotive, aerospace, and energy production industries. The fact that wide bandgap semiconductors are capable of electronic functionality at much higher temperatures than silicon has partially fueled their development, particularly in the case of SiC. It appears unlikely that wide bandgap semiconductor devices will find much use in low-power transistor applications until the ambient temperature exceeds approximately 300 C, as commercially available silicon and silicon-on-insulator technologies are already satisfying requirements for digital and analog very large scale integrated circuits in this temperature range. However, practical operation of silicon power devices at ambient temperatures above 200 C appears problematic, as self-heating at higher power levels results in high internal junction temperatures and leakages. Thus, most electronic subsystems that simultaneously require high-temperature and high-power operation will necessarily be realized using wide bandgap devices, once the technology for realizing these devices become sufficiently developed that they become widely available. Technological challenges impeding the realization of beneficial wide bandgap high ambient temperature electronics, including material growth, contacts, and packaging, are briefly discussed.

  9. Low temperature and high pressure crystals of room temperature ionic liquid: N, N-diethyl-N-methyl-N-(2-methoxyethyl) ammonium tetrafluoroborate

    International Nuclear Information System (INIS)

    Abe, Hiroshi; Imai, Yusuke; Takekiyo, Takahiro; Yoshimura, Yukihiro; Hamaya, Nozomu

    2014-01-01

    Crystals of room temperature ionic liquid (RTIL) are obtained separately at low temperature or under high pressure. The RTIL is N, N-diethyl-N-methyl-N-(2-methoxyethyl) ammonium tetrafluoroborate, [DEME][BF 4 ]. At ambient pressure, low-temperature (LT) crystals appeared on slow cooling. By simultaneous X-ray diffraction and differential scanning calorimetry (DSC) measurements, metastable monoclinic and stable orthorhombic phases coexist in pure [DEME][BF 4 ]. Furthermore, the DSC thermal trace indicates that the metastable monoclinic phase was stabilized by adding water. In contrast, on compression process up to 7.6 GPa, crystallization is completely suppressed even upon slow compression. Direct observations using optical microscopy also support no crystal domain growth on compression process. High-pressure (HP) crystals at room temperature were seen only on decompression process, where two different kinds of crystals appeared subsequently. By crystal structure analysis, the LT crystal structures have no relation with the HP ones. Moreover, both metastable monoclinic phase at low temperature and higher pressure crystal has a folding molecular conformation and anti-parallel pairing of the [DEME] cation as the instability factors

  10. Temperature gradient driven electron transport in NSTX and Tore Supra

    International Nuclear Information System (INIS)

    Horton, W.; Wong, H.V.; Morrison, P.J.; Wurm, A.; Kim, J.H.; Perez, J.C.; Pratt, J.; Hoang, G.T.; LeBlanc, B.P.; Ball, R.

    2005-01-01

    Electron thermal fluxes are derived from the power balance for Tore Supra (TS) and NSTX discharges with centrally deposited fast wave electron heating. Measurements of the electron temperature and density profiles, combined with ray tracing computations of the power absorption profiles, allow detailed interpretation of the thermal flux versus temperature gradient. Evidence supporting the occurrence of electron temperature gradient turbulent transport in the two confinement devices is found. With control of the magnetic rotational transform profile and the heating power, internal transport barriers are created in TS and NSTX discharges. These partial transport barriers are argued to be a universal feature of transport equations in the presence of invariant tori that are intrinsic to non-monotonic rotational transforms in dynamical systems

  11. ELECTRON ENERGY DECAY IN HELIUM AFTERGLOW PLASMAS AT CRYOGENIC TEMPERATURES

    Energy Technology Data Exchange (ETDEWEB)

    Goldan, P. D.; Cahn, J. H.; Goldstein, L.

    1963-10-15

    Studies of decaying afterglow plasmas in helium were ined near 4 deg K by immersion in a liquid helium bath. By means of a Maser Radiometer System, the electron temperature was followed below 200 deg K. Guided microwave propagation and wave interaction techniques premit determination of election number density and collision frequencies for momentum transfer. Electron temperature decay rates of the order of 150 mu sec/p(mm Hg alpha 4.2 deg K) were found. Since thermal relaxation by elastic collisions should be some two orders of magnitude faster than this, the electrons appear to be in quasiequilibrium with a slowly decaying internal heating source. Correlation of the expected decay rates of singlet metastable helium atoms with the electron temperature decay gives good agreement with the present experiment. (auth)

  12. Production of jet fuel range paraffins by low temperature polymerization of gaseous light olefins using ionic liquid

    International Nuclear Information System (INIS)

    Jiang, Peiwen; Wu, Xiaoping; Zhu, Lijuan; Jin, Feng; Liu, Junxu; Xia, Tongyan; Wang, Tiejun; Li, Quanxin

    2016-01-01

    Graphical abstract: A novel catalytic transformation of light olefins into jet fuel range iso-paraffins by the low-temperature olefin polymerizations under atmospheric conditions. - Highlights: • A novel transformation of light olefins to jet fuel range paraffins was demonstrated. • The synthetic fuels can be produced by atmospheric olefin polymerizations. • C 8 –C 15 iso-paraffins from light olefins was achieved with a selectivity of 80.6%. - Abstract: This work demonstrated a novel catalytic transformation of gaseous olefins into jet fuel range iso-paraffins by the low-temperature olefin polymerizations under atmospheric conditions. The production of the desired C 8 –C 15 iso-paraffins with the selectivity of 80.6 C mol% was achieved by the room-temperature polymerizations of gaseous light olefins using the [BMIM] Al 2 Cl 7 ionic liquid. The influences of the reaction conditions on the olefinic polymerizations were investigated in detail. The properties of hydrocarbons in the synthetic fuels were determined by the GC–MS analyses combined with 1 H NMR, and 13 C NMR analyses. The formation of C 8 –C 15 hydrocarbons from gaseous light olefins was illustrated by the identified products and the functional groups. This transformation potentially provides a useful avenue for the production of the most important components of iso-paraffins required in jet fuels.

  13. Extraction of Am(III) using novel solvent systems containing a tripodal diglycolamide ligand in room temperature ionic liquids: a 'green' approach for radioactive waste processing

    NARCIS (Netherlands)

    Sengupta, A; Mohapatra, P.K.; Iqbal, M.; Verboom, Willem; Huskens, Jurriaan; Godbole, S.V.

    2012-01-01

    Extraction of Am3+ from acidic feed solutions was investigated using novel solvent systems containing a tripodal diglycolamide (T-DGA) in three room temperature ionic liquids (RTIL), viz. [C4mim][NTf2], [C6mim][NTf2] and [C8mim][NTf2]. Compared to the results obtained with N,N,N′,N′-tetra-n-octyl

  14. Ionic liquids as electrolytes

    International Nuclear Information System (INIS)

    Galinski, Maciej; Lewandowski, Andrzej; Stepniak, Izabela

    2006-01-01

    Salts having a low melting point are liquid at room temperature, or even below, and form a new class of liquids usually called room temperature ionic liquids (RTIL). Information about RTILs can be found in the literature with such key words as: room temperature molten salt, low-temperature molten salt, ambient-temperature molten salt, liquid organic salt or simply ionic liquid. Their physicochemical properties are the same as high temperature ionic liquids, but the practical aspects of their maintenance or handling are different enough to merit a distinction. The class of ionic liquids, based on tetraalkylammonium cation and chloroaluminate anion, has been extensively studied since late 1970s of the XX century, following the works of Osteryoung. Systematic research on the application of chloroaluminate ionic liquids as solvents was performed in 1980s. However, ionic liquids based on aluminium halides are moisture sensitive. During the last decade an increasing number of new ionic liquids have been prepared and used as solvents. The general aim of this paper was to review the physical and chemical properties of RTILs from the point of view of their possible application as electrolytes in electrochemical processes and devices. The following points are discussed: melting and freezing, conductivity, viscosity, temperature dependence of conductivity, transport and transference numbers, electrochemical stability, possible application in aluminium electroplating, lithium batteries and in electrochemical capacitors

  15. Analysis of electron cyclotron emission spectra of high electron temperature, supershot plasmas in TFTR

    International Nuclear Information System (INIS)

    Taylor, G.; Arunasalam, V.; Efthimion, P.C.; Grek, B.

    1993-01-01

    A primary objective of the TFTR program since 1986 has been the study and optimization of deuterium Supershot plasmas. These plasmas are predominantly heated by 90-110 keV neutral deuterium beams (P NBI /P OH >30), central ion temperatures are ∝30 keV and central electron temperatures from ECE (T ECE ) often exceed 10 keV. Central electron temperature data measured with a TV Thomson scattering (TVTS) system (T TVTS ) during the period 1987-1990 have been compared with data from three different ECE instruments on TFTR. Although T ECE ∝T TVTS for temperatures below 6 keV, there is a systematically increasing disagreement at higher electron temperatures, with T ECE ∝1.2 T TVTS for T TVTS in the range 9-10 keV. Recent theoretical work on the ECE radiation temperature of non-equilibrium plasmas indicates that for a bi-Maxwellian electron velocity distribution with a ratio of tail to bulk electron density η, a bulk temperature T b , and a hot tail temperature T h , the perpendicular ECE radiation temperature is given by T ECE ∝T b {1+η(T h /T b )}, for η ECE would be enhanced over T TVTS by a factor which depends on η and T h . This paper investigates whether the discrepancy between T TVTS and T ECE seen in TFTR Supershots at high electron temperatures is due to the presence of a hot electron tail component. The extraordinary mode ECE spectrum at the second, third and fourth harmonics is measured on the horizontal midplane by an absolutely calibrated ECE Michelson interferometer. This ECE spectrum is compared with the output from a time-independent transport code with relativistic opacity which solves the three-dimensional ECE radiation transport in a toroidally symmetric, two-dimensional geometry and uses measured electron density and temperature profiles from the TVTS system. (orig.)

  16. The influence of mesoscopic confinement on the dynamics of imidazolium-based room temperature ionic liquids in polyether sulfone membranes

    Science.gov (United States)

    Thomaz, Joseph E.; Bailey, Heather E.; Fayer, Michael D.

    2017-11-01

    The structural dynamics of a series of 1-alkyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (CnmimNTf2, n = 2, 4, 6, 10: ethyl—Emim; butyl—Bmim; hexyl—Hmim; decyl—Dmim) room temperature ionic liquids confined in the pores of polyether sulfone (PES 200) membranes with an average pore size of ˜350 nm and in the bulk liquids were studied. Time correlated single photon counting measurements of the fluorescence of the fluorophore coumarin 153 (C153) were used to observe the time-dependent Stokes shift (solvation dynamics). The solvation dynamics of C153 in the ionic liquids are multiexponential decays. The multiexponential functional form of the decays was confirmed as the slowest decay component of each bulk liquid matches the slowest component of the liquid dynamics measured by optical heterodyne-detected optical Kerr effect (OHD-OKE) experiments, which is single exponential. The fact that the slowest component of the Stokes shift matches the OHD-OKE data in all four liquids identifies this component of the solvation dynamics as arising from the complete structural randomization of the liquids. Although the pores in the PES membranes are large, confinement on the mesoscopic length scale results in substantial slowing of the dynamics, a factor of ˜4, for EmimNTf2, with the effect decreasing as the chain length increases. By DmimNTf2, the dynamics are virtually indistinguishable from those in the bulk liquid. The rotation relaxation of C153 in the four bulk liquids was also measured and showed strong coupling between the C153 probe and its environment.

  17. Ion- and electron-acoustic solitons in two-electron temperature space plasmas

    International Nuclear Information System (INIS)

    Lakhina, G. S.; Kakad, A. P.; Singh, S. V.; Verheest, F.

    2008-01-01

    Properties of ion- and electron-acoustic solitons are investigated in an unmagnetized multicomponent plasma system consisting of cold and hot electrons and hot ions using the Sagdeev pseudopotential technique. The analysis is based on fluid equations and the Poisson equation. Solitary wave solutions are found when the Mach numbers exceed some critical values. The critical Mach numbers for the ion-acoustic solitons are found to be smaller than those for electron-acoustic solitons for a given set of plasma parameters. The critical Mach numbers of ion-acoustic solitons increase with the increase of hot electron temperature and the decrease of cold electron density. On the other hand, the critical Mach numbers of electron-acoustic solitons increase with the increase of the cold electron density as well as the hot electron temperature. The ion-acoustic solitons have positive potentials for the parameters considered. However, the electron-acoustic solitons have positive or negative potentials depending whether the fractional cold electron density with respect to the ion density is greater or less than a certain critical value. Further, the amplitudes of both the ion- and electron-acoustic solitons increase with the increase of the hot electron temperature. Possible application of this model to electrostatic solitary waves observed on the auroral field lines by the Viking spacecraft is discussed

  18. Temperature dependence of electronic transport property in ferroelectric polymer films

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, X.L.; Wang, J.L., E-mail: jlwang@mail.sitp.ac.cn; Tian, B.B.; Liu, B.L.; Zou, Y.H.; Wang, X.D.; Sun, S.; Sun, J.L., E-mail: jlsun@mail.sitp.ac.cn; Meng, X.J.; Chu, J.H.

    2014-10-15

    Highlights: • The ferroelectric polymer was fabricated by Langmuir–Blodgett method. • The electrons as the dominant injected carrier were conformed in the ferroelectric polymer films. • The leakage current conduction mechanisms in ferroelectric polymer were investigated. - Abstract: The leakage current mechanism of ferroelectric copolymer of polyvinylidene fluoride with trifluoroethylene prepared by Langmuir–Blodgett was investigated in the temperature range from 100 K to 350 K. The electron as the dominant injected carrier was observed in the ferroelectric copolymer films. The transport mechanisms in copolymer strongly depend on the temperature and applied voltage. From 100 K to 200 K, Schottky emission dominates the conduction. With temperature increasing, the Frenkel–Poole emission instead of the Schottky emission to conduct the carrier transport. When the temperature gets to 260 K, the leakage current becomes independent of temperature, and the space charge limited current conduction was observed.

  19. Dynamics and Interactions in Room Temperature Ionic Liquids, Surfaces and Interfaces

    Science.gov (United States)

    2016-01-13

    OHD-OKE) experiments. The first 2D IR experiments on functionalized SiO2 planar surface monolayers of alkyl chains with a vibrational probe head group...alkyl groups lowers the temperature for crystallization below room temperature and can also result in supercooling and glass formation rather than...heterodyne detected optical Kerr effect (OHD-OKE) experiments. During the grant, we performed the first 2D IR experiments on functionalized SiO2

  20. Structure and dynamics of biomembranes in room-temperature ionic liquid water solutions studied by neutron scattering and by molecular dynamics simulations

    Science.gov (United States)

    Benedetto, Antonio; Ballone, Pietro

    2018-05-01

    Increasing attention is being devoted to the interaction of a new class of organic ionic liquids known as room-temperature ionic liquids (RTILs) with biomolecules, partly because of health and environment concerns, and, even more, for the prospect of exciting new applications in biomedicine, sensing and energy technologies. Here we focus on the interaction between RTILs and phospholipid bilayers that are well-accepted models for bio-membranes. We discuss how neutron scattering has been used to probe both the structure and the dynamics of these systems, and how its integration with molecular dynamics simulation has allowed the determination of the microscopic details of their interaction.

  1. Isotope effect in glass-transition temperature and ionic conductivity of lithium-borate glasses

    International Nuclear Information System (INIS)

    Nagasaki, Takanori; Morishima, Ryuta; Matsui, Tsuneo

    2002-01-01

    The glass-transition temperature and the electrical conductivity of lithium borate (0.33Li 2 O-0.67B 2 O 3 ) glasses with various isotopic compositions were determined by differential thermal analysis and by impedance spectroscopy, respectively. The obtained glass-transition temperature as well as the vibrational frequency of B-O network structure was independent of lithium isotopic composition. This result indicates that lithium ions, which exist as network modifier, only weakly interact with B-O network structure. In addition, the glass-transition temperature increased with 10 B content although the reason has not been understood. The electrical conductivity, on the other hand, increased with 6 Li content. The ratio of the conductivity of 6 Li glass to that of 7 Li glass was found to be 2, being larger than the value (7/6) 1/2 calculated with the simple classical diffusion theory. This strong mass dependence could be explained by the dynamic structure model, which assumes local structural relaxation even far below the glass-transition temperature. Besides, the conductivity appeared to increase with the glass-transition temperature. Possible correlations between the glass-transition temperature and the electrical conductivity were discussed. (author)

  2. Ionic Polymer-Based Removable and Charge-Dissipative Coatings for Space Electronic Applications, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Protection of critical electronic systems in spacecraft and satellites is imperative for NASA's future missions to high-energy, outer-planet environments. The...

  3. Effects of lower hybrid fast electron populations on electron temperature measurements at JET

    International Nuclear Information System (INIS)

    Tanzi, C.P.; Bartlett, D.V.; Schunke, B.

    1993-01-01

    The Lower Hybrid Current Drive (LHCD) system on JET has to date achieved up to 1.5 MA of driven current. This current is carried by a fast electron population with energies more than ten times the electron temperature and density about 10 -4 of the bulk plasma. This paper discusses the effects of this fast electron population on our ability to make reliable temperature measurements using ECE and reviews the effects on other plasma diagnostics which rely on ECE temperature measurements for their interpretation. (orig.)

  4. Temperature and ionic strength influences on actinide(VI)/(V) redox potentials for carbonate limiting complexes

    International Nuclear Information System (INIS)

    Capdevila, H.; Vitorge, P.

    1998-01-01

    Actinide behaviour was studied in two limiting aqueous solutions: acidic and carbonate. Cyclic voltametry was validated with well-known U redox system. SIT was used to account for I influence. Taylor's series expansions to the second order were used to account for T influence. Redox potentials of actinide couples had previously been measured in non complexing media. The above data treatments give standard values for redox potential E 0 , for the corresponding entropy ΔS 0 , enthalpy ΔH 0 and heat capacity ΔC p 0 changes, and also for the corresponding excess values (i.e. the variation of these thermodynamic constants with ionic strength). This methodology was here used in carbonate media to measure the potential of the redox couple PuO 2 (CO 3 ) 3 4- /PuO 2 (CO 3 ) 3 5- from 5 to 70 degC and from I = 0.5 to 4.5 M in Na 2 CO 3 , NaClO 4 media. Experimental details and full results are given for Pu. Only final results are given for Np. Previous and/or published data for U and Am are discussed. E and ΔS variations with T or I were enough to be measured. The values obtained for the fitted SIT coefficients Δε, and for ΔS and ΔCp are similar for U, Np and Pu redox reactions. Using this analogy for Am missing data is discussed. β 3 V /β 3 VI formation constant ratio of the carbonate limiting complexes were deduced from the potential shift from complexing to non complexing media for the Actinide(VI)/Actinide(V) redox couples. β 3 V (U and Pu) and β 3 VI (Np) were finally proposed using published β3 VI (U and Pu) and β 3 V (Np). For Am, this data treatment was used to discuss the AmO 2 2+ / AmO 2 + redox potential

  5. Influence of the ionic radii on the transition temperature of tilted perovskites

    Energy Technology Data Exchange (ETDEWEB)

    Chaves, A S [Minas Gerais Univ., Belo Horizonte (Brazil). Inst. de Fisica

    1979-03-01

    It is shown that the temperature of the transition to the cubic phase in the perovskites with tilted octahedra, considering compounds with the same central ion, is a decreasing function of the tolerance factor. An explanation is given in terms of empty spaces of the crystal structure and the rms thermal necessary to fill them.

  6. Electron spectroscopy on high-temperature superconductors and related compounds

    International Nuclear Information System (INIS)

    Knupfer, M.

    1994-01-01

    In the last two classes of materials have been discovered which distinguish themselves due to a transition into the superconducting state at relatively high temperatures. These are the cuprate superconductors and the alkali metal doped fullerenes. In this work the electronic structure of representatives of these materials, undoped and Ca-doped YBa 2 Cu 4 O 8 and A 3 C 60 (A=K, Rb), has been investigated using electron energy-loss spectroscopy and photoemission spectroscopy. (orig.) [de

  7. Study of effect of composition, irradiation and quenching on ionic ...

    Indian Academy of Sciences (India)

    The electrolyte samples are also quenched at liquid nitrogen temperature and conductivity measurements are carried out. The ionic conductivity at room temperature exhibits a characteristic peak for the composition, = 46. Electron beam irradiation results in an increase in conductivity for all compositions by a factor of 2–3.

  8. Evolution of the electronic and ionic structure of Mg clusters with increase in cluster size

    DEFF Research Database (Denmark)

    Lyalin, Andrey G.; Solov'yov, Ilia; Solov'yov, Andrey V.

    2003-01-01

    The optimized structure and electronic properties of neutral and singly charged magnesium clusters have been investigated using ab initio theoretical methods based on density-functional theory and systematic post–Hartree-Fock many-body perturbation theory accounting for all electrons in the system....... We have investigated the appearance of the elements of the hcp structure and metallic evolution of the magnesium clusters, as well as the stability of linear chains and rings of magnesium atoms. The results obtained are compared with the available experimental data and the results of other...

  9. The relationship between ionospheric temperature, electron density and solar activity

    International Nuclear Information System (INIS)

    McDonald, J.N.; Williams, P.J.S.

    1980-01-01

    In studying the F-region of the ionosphere several authors have concluded that the difference between the electron temperature Tsub(e) and the ion temperature Tsub(i) is related to the electron density N. It was later noted that solar activity (S) was involved and an empirical relationship of the following form was established: Tsub(e)-Tsub(i) = A-BN+CS. The present paper extends this work using day-time data over a four year period. The results are given and discussed. A modified form of the empirical relation is proposed. (U.K.)

  10. Electron temperature effects for an ion beam source

    International Nuclear Information System (INIS)

    Uramoto, Joshin.

    1979-05-01

    A hydrogen high temperature plasma up to 200 eV is produced by acceleration of electrons in a hot hollow cathode discharge and is used as an ion beam source. Then, two characteristics are observed: A rate of the atomic ion (H + ) number increases above 70%. A perveance of the ion beam increases above 30 times compared with that of a cold plasma, while a floating potential of an ion acceleration electrode approaches an ion acceleration potential (- 500 V) according as an increment of the electron temperature. Moreover, a neutralized ion beam can be produced by only the negative floating electrode without an external power supply. (author)

  11. Electron temperature measurement of tungsten inert gas arcs

    International Nuclear Information System (INIS)

    Tanaka, Manabu; Tashiro, Shinichi

    2008-01-01

    In order to make clear the physical grounds of deviations from LTE (Local Thermodynamic Equilibrium) in the atmospheric helium TIG arcs electron temperature and LTE temperature obtained from electron number density were measured by using of line-profile analysis of the laser scattering method without an assumption of LTE. The experimental results showed that in comparison with the argon TIG arcs, the region where a deviation from LTE occurs tends to expand in higher arc current because the plasma reaches the similar state to LTE within shorter distance from the cathode due to the slower cathode jet velocity

  12. Signature of electron-phonon interaction in high temperature superconductors

    Directory of Open Access Journals (Sweden)

    Vinod Ashokan

    2011-09-01

    Full Text Available The theory of thermal conductivity of high temperature superconductors (HTS based on electron and phonon line width (life times formulation is developed with Quantum dynamical approach of Green's function. The frequency line width is observed as an extremely sensitive quantity in the transport phenomena of HTS as a collection of large number of scattering processes. The role of resonance scattering and electron-phonon interaction processes is found to be most prominent near critical temperature. The theory successfully explains the spectacular behaviour of high Tc superconductors in the vicinity of transition temperature. A successful agreement between theory and experiment has been obtained by analyzing the thermal conductivity data for the sample La1.8Sr0.2CuO4 in the temperature range 0 − 200K. The theory is equally and successfully applicable to all other high Tc superconductors.

  13. Time-resolving electron temperature diagnostic for ALCATOR C

    International Nuclear Information System (INIS)

    Fairfax, S.A.

    1984-05-01

    A diagnostic that provides time-resolved central electron temperatures has been designed, built, and tested on the ALCATOR C Tokamak. The diagnostic uses an array of fixed-wavelength x-ray crystal monochromators to sample the x-ray continuum and determine the absolute electron temperature. The resolution and central energy of each channel were chosen to exclude any contributions from impurity line radiation. This document describes the need for such a diagnostic, the design methodology, and the results with typical ALCATOR C plasmas. Sawtooth (m = 1) temperature oscillations were observed after pellet fueling of the plasma. This is the first time that such oscillations have been observed with an x-ray temperature diagnostic

  14. Electron microscopic observation at low temperature on superconductors

    International Nuclear Information System (INIS)

    Yokota, Yasuhiro; Hashimoto, Hatsujiro; Yoshida, Hiroyuki.

    1991-01-01

    The authors have observed superconducting materials with a high resolution electron microscope at liquid helium temperature. First, observation was carried out on Nb system intermetallic compounds such as Nb 3 Al and Nb 3 Sn of Al 5 type and Nb 3 Ge of 11 type at extremely low temperature. Next, the observation of high temperature superconductive ceramics in the state of superconductivity was attempted. In this paper, first the development of the liquid helium sample holder for a 400 kV electron microscope to realize the observation is reported. Besides, the sample holder of Gatan Co. and an extremely low temperature, high resolution electron microscope with a superconducting lens are described. The purpose of carrying out the electron microscope observation of superconductors at low temperature is the direct observation of the crystalline lattice image in the state of superconductivity. Also the structural transformation from tetragonal crystals to rhombic crystals in Al 5 type superconductors can be observed. The results of observation are reported. (K.I.)

  15. Determining coronal electron temperatures from observations with UVCS/SOHO

    Science.gov (United States)

    Fineschi, S.; Esser, R.; Habbal, S. R.; Karovska, M.; Romoli, M.; Strachan, L.; Kohl, J. L.; Huber, M. C. E.

    1995-01-01

    The electron temperature is a fundamental physical parameter of the coronal plasma. Currently, there are no direct measurements of this quantity in the extended corona. Observations with the Ultraviolet Coronagraph Spectrometer (UVCS) aboard the upcoming Solar and Heliospheric Observatory (SOHO) mission can provide the most direct determination of the electron kinetic temperature (or, more precisely, the electron velocity distribution along the line of sight). This measurement is based on the observation of the Thomson-scattered Lyman alpha (Ly-alpha) profile. This observation is made particularly challenging by the fact that the integrated intensity of the electron-scattered Ly-alpha line is about 10(exp 3) times fainter than that of the resonantly-scattered Ly-alpha component. In addition, the former is distributed across 50 A (FWHM), unlike the latter that is concentrated in 1 A. These facts impose stringent requirements on the stray-light rejection properties of the coronagraph/spectrometer, and in particular on the requirements for the grating. We make use of laboratory measurements of the UVCS Ly-alpha grating stray-light, and of simulated electron-scattered Ly-alpha profiles to estimate the expected confidence levels of electron temperature determination. Models of different structures typical of the corona (e.g., streamers, coronal holes) are used for this parameter study.

  16. Substitution of conventional high-temperature syntheses of inorganic compounds by near-room-temperature syntheses in ionic liquids

    KAUST Repository

    Groh, Matthias Friedrich; Mü llera, Ulrike; Ahmed, Ejaz; Rothenberger, Alexander; Ruck, Michael J.

    2013-01-01

    The high-temperature syntheses of the low-valent halogenides P2I4, Te2Br, α-Te4I4, Te4(Al2Cl7)2, Te4(Bi6Cl20), Te8(Bi4Cl14),Bi8(AlCl4)2, Bi6Cl7,and Bi6Br7, as well as of WSCl4 andWOCl4 have been replaced by resource-efficient low

  17. Multiple scattering in electron fluid and energy loss in multi-ionic targets

    Energy Technology Data Exchange (ETDEWEB)

    Deutsch, C., E-mail: claude.deutsch@u-psud.fr [LPGP, UParis-Sud, 91405-Orsay (France); Tahir, N.A. [GSI, 1Planck Str., 64291-Darmstadt (Germany); Barriga-Carrasco, M. [ETSII, UCastilla-la-Mancha, 13071 Ciudad-Real (Spain); Ceban, V. [LPGP, UParis-Sud, 91405-Orsay (France); Fromy, P. [CRI, UParis-Sud, 91405-Orsay (France); Gilles, D. [CEA/Saclay/DSM/IRFU/SAP, 91191-Gif-s-Yvette (France); Leger, D. [Laboratoire Monthouy, UValenciennes-Hainaut Cambresis (France); Maynard, G. [LPGP, UParis-Sud, 91405-Orsay (France); Tashev, B. [Department of Physics, KazNu, Tole Bi82, Almaty (Kazakhstan); Volpe, L. [Department of Physics, UMilano-Bicocca, Milano 20126 (Italy)

    2014-01-01

    Extensions of the standard stopping model (SSM) for ion projectiles interacting with dense targets of timely concern for ICF and WDM are reviewed. They include multiple scattering on partially degenerate electrons, low velocity ion slowing down in demixing H–He mixtures within Jovian planets core or multiionic target such as Kapton.

  18. Multiple scattering in electron fluid and energy loss in multi-ionic targets

    International Nuclear Information System (INIS)

    Deutsch, C.; Tahir, N.A.; Barriga-Carrasco, M.; Ceban, V.; Fromy, P.; Gilles, D.; Leger, D.; Maynard, G.; Tashev, B.; Volpe, L.

    2014-01-01

    Extensions of the standard stopping model (SSM) for ion projectiles interacting with dense targets of timely concern for ICF and WDM are reviewed. They include multiple scattering on partially degenerate electrons, low velocity ion slowing down in demixing H–He mixtures within Jovian planets core or multiionic target such as Kapton

  19. Survey of potential electronic applications of high temperature superconductors

    International Nuclear Information System (INIS)

    Hammond, R.B.; Bourne, L.C.

    1991-01-01

    In this paper the authors present a survey of the potential electronic applications of high temperature superconductor (HTSC) thin films. During the past four years there has been substantial speculation on this topic. The authors will cover only a small fraction of the potential electronic applications that have been identified. Their treatment is influenced by the developments over the past few years in materials and device development and in market analysis. They present their view of the most promising potential applications. Superconductors have two important properties that make them attractive for electronic applications. These are (a) low surface resistance at high frequencies, and (b) the Josephson effect

  20. High-temperature dehydration behavior and ionic conduction of 2,5-dimethylanilinium chloride monohydrate

    Energy Technology Data Exchange (ETDEWEB)

    Guidara, Sameh, E-mail: sameh_guidara@yahoo.fr; Feki, Habib; Abid, Younes

    2016-07-05

    The 2,5-dimethylanilinium chloride monohydrate compound is obtained by slow evaporation at room temperature. This material is characterized by DSC, X-Ray powder diffraction, Raman and impedance spectroscopy technique measured in the 2.10{sup 2}–5.10{sup 6} Hz frequency and 292–422 K temperature ranges. The calorimetric study has revealed three endothermic peaks at 355 K, 392 K and 403 K which defines four successive phases denoted I, II, III and IV. The first peak corresponds to water escape from the crystal. After heating above 355 K, the compound dehydrates and the crystal space group changes from non-centrosymmetric to centrosymmetric symmetry. The activation energy responsible for dielectric relaxation extracted from the modulus spectra is found to be almost the same as the value obtained from temperature variation of dc conductivity for phases I and IV. These results indicate that the transport is through ion hopping mechanism. The influence of the dehydration process on the compound conductivity was also discussed. - Highlights: • The calorimetric study of 2,5-DACM has revealed three endothermic peaks. • The dielectrical properties were studied using the impedance measurements. • The X ray powder diffraction has been performed. • The mobility of the charge carriers was reported and discussed.

  1. Positron and electron energy bands in several ionic crystals using restricted Hartree-Fock method

    Science.gov (United States)

    Kunz, A. B.; Waber, J. T.

    1981-08-01

    Using a restricted Hartree-Fock formalism and suitably localized and symmetrized wave functions, both the positron and electron energy bands were calculated for NaF, MgO and NiO. The lowest positron state at Γ 1 lies above the vacuum level and negative work functions are predicted. Positron annihilation rates were calculated and found to be in good agreement with measured lifetimes.

  2. Inelastic vibrational bulk and surface losses of swift electrons in ionic nanostructures

    Science.gov (United States)

    Hohenester, Ulrich; Trügler, Andreas; Batson, Philip E.; Lagos, Maureen J.

    2018-04-01

    In a recent paper [Lagos et al., Nature (London) 543, 533 (2017), 10.1038/nature21699] we have used electron energy loss spectroscopy with sub-10 meV energy and atomic spatial resolution to map optical and acoustic, bulk and surface vibrational modes in magnesium oxide nanocubes. We found that a local dielectric description works well for the simulation of aloof geometries, similar to related work for surface plasmons and surface plasmon polaritons, while for intersecting geometries such a description fails to reproduce the rich spectral features associated with excitation of bulk acoustic and optical phonons. To account for scatterings with a finite momentum exchange, in this paper we investigate molecular and lattice dynamics simulations of bulk losses in magnesium-oxide nanocubes using a rigid-ion description and investigate the loss spectra for intersecting electron beams. From our analysis we can evaluate the capability of electron energy loss spectroscopy for the investigation of phonon modes at the nanoscale, and we discuss shortcomings of our simplified approach as well as directions for future investigations.

  3. In-Situ Microprobe Observations of Dispersed Oil with Low-Temperature Low-Vacuum Scanning Electron Microscope

    International Nuclear Information System (INIS)

    Mohsen, H.T.

    2010-01-01

    A low cost cryostat stage from high heat capacity material is designed and constructed, in attempt to apply size distribution techniques for examination of oil dispersions. Different materials were tested according to their heat capacity to keep the liquid under investigation in frozen state as long as possible during the introduction of the cryostat stage to the low-vacuum scanning electron microscope. Different concentrations of non ionic surfactant were added to artificially contaminated with 10000 ppm Balayeam base oil in 3.5 % saline water, where oil and dispersing liquid have been added and shacked well to be investigated under the microscope as fine frozen droplets. The efficiency of dispersion was examined using low temperature low-vacuum scanning electron microscope. The shape and size distributions of freeze oil droplets were studied by digital imaging processing technique in conjunction with scanning electron microscope counting method. Also elemental concentration of oil droplets was analyzed.

  4. Measurements of plasma temperature and electron density in laser

    Indian Academy of Sciences (India)

    The temperature and electron density characterizing the plasma are measured by time-resolved spectroscopy of neutral atom and ion line emissions in the time window of 300–2000 ns. An echelle spectrograph coupled with a gated intensified charge coupled detector is used to record the plasma emissions.

  5. Electronically induced nuclear transitions - temperature dependence and Rabi oscillations

    International Nuclear Information System (INIS)

    Niez, J.J.

    2002-01-01

    This paper deals with a nucleus electromagnetically coupled with the bound states of its electronic surroundings. It describes the temperature dependence of its dynamics and the onset of potential Rabi oscillations by means of a Master Equation. The latter is generalized in order to account for possible strong resonances. Throughout the paper the approximation schemes are discussed and tested. (authors)

  6. Electron-dislocation interaction at low temperatures. Progress report

    International Nuclear Information System (INIS)

    1978-01-01

    The interaction of mobile dislocations with electrons in copper and copper alloys has shown that dislocation motion in copper, at low temperature, can be treated as an analog of an underdamped oscillator. We have also shown that the viscous drag on mobile dislocations in type II superconductors can be treated as an acoustic attenuation of an elastic wave

  7. Low latitude electron temperature observed by the CHAMP satellite

    DEFF Research Database (Denmark)

    Stolle, Claudia; Truhlik, V.; Richards, P.

    2012-01-01

    Te morning overshoot (MO). Both, data and model revealed an anti-correlation between the equatorial MO amplitude and solar EUV flux at these altitudes. The CHAMP observations also reveal a post sunset electron temperature anomaly in analogy to the equatorial ionisation anomaly at altitudes below 400...

  8. Temperature dependence of electron concentration in cadmium arsenide

    NARCIS (Netherlands)

    Gelten, M.J.; Blom, F.A.P.

    1979-01-01

    From measurements of the temperature dependence of the electron concentration in Cd 3 As 2 , we found values for the conduction-band parameters that are in good agreement with those recently reported by Aubin, Caron, and Jay-Gerin. However, in contrast with these authors we found no small overlap,

  9. Characterization of electron temperature by simulating a multicusp ion source

    Energy Technology Data Exchange (ETDEWEB)

    Yeon, Yeong Heum [Sungkyunkwan University, WCU Department of Energy Science, 2066, Seobu-ro, Jangan-gu, Suwon-si (Korea, Republic of); Ghergherehchi, Mitra; Kim, Sang Bum; Jun, Woo Jung [Sungkyunkwan University, School of Information & Communication Engineering, 2066, Seobu-ro, Jangan-gu, Suwon-si (Korea, Republic of); Lee, Jong Chul; Mohamed Gad, Khaled Mohamed [Sungkyunkwan University, WCU Department of Energy Science, 2066, Seobu-ro, Jangan-gu, Suwon-si (Korea, Republic of); Namgoong, Ho [Sungkyunkwan University, School of Information & Communication Engineering, 2066, Seobu-ro, Jangan-gu, Suwon-si (Korea, Republic of); Chai, Jong Seo, E-mail: jschai@skku.edu [Sungkyunkwan University, School of Information & Communication Engineering, 2066, Seobu-ro, Jangan-gu, Suwon-si (Korea, Republic of)

    2016-12-01

    Multicusp ion sources are used in cyclotrons and linear accelerators to produce high beam currents. The structure of a multicusp ion source consists of permanent magnets, filaments, and an anode body. The configuration of the array of permanent magnets, discharge voltage of the plasma, extraction bias voltage, and structure of the multicusp ion source body decide the quality of the beam. The electrons are emitted from the filament by thermionic emission. The emission current can be calculated from thermal information pertaining to the filament, and from the applied voltage and current. The electron trajectories were calculated using CST Particle Studio to optimize the plasma. The array configuration of the permanent magnets decides the magnetic field inside the ion source. The extraction bias voltage and the structure of the multicusp ion source body decide the electric field. Optimization of the electromagnetic field was performed with these factors. CST Particle Studio was used to calculate the electron temperature with a varying permanent magnet array. Four types of permanent magnet array were simulated to optimize the electron temperature. It was found that a 2-layer full line cusp field (with inverse field) produced the best electron temperature control behavior.

  10. A study of chemical modifications of a Nafion membrane by incorporation of different room temperature ionic liquids

    Energy Technology Data Exchange (ETDEWEB)

    Martinez de Yuso, M.V.; Rodriguez-Castellon, E. [Departamento de Quimica Inorganica, Facultad de Ciencias, Universidad de Malaga (Spain); Neves, L.A.; Coelhoso, I.M.; Crespo, J.G. [REQUIMTE/CQFB, Departamento de Quimica, Universidade Nova de Lisboa, Caparica (Portugal); Benavente, J. [Departamento de Fisica Aplicada I, Facultad de Ciencias, Universidad de Malaga (Spain)

    2012-08-15

    Surface and bulk chemical changes in a Nafion membrane as a result of room temperature ionic liquids (RTILs) incorporation were determined by X-ray photoelectron spectroscopy (XPS) and elemental analysis, respectively. RTILs with different physicochemical properties were selected. Two imidazolium based RTIL-cations (1-octyl-3-methylimidazolium and 1-butyl-3-methylimidazolium) were used to detect the effect of cation size on membrane modification, while the effect of the RTIL hydrophilic/hydrophobic character was also considered by choosing different anions. Angle resolved XPS measurements (ARXPS) were carried out varying the angle of analysis between 15 and 75 to get elemental information on the Nafion/RTIL-modified membranes interactions for a deepness of around 10 nm. Moreover, changes in the RTIL-modified membranes associated to thermal effect were also considered by analyzing the samples after their heating at 120 C for 24 h. Agreement between both chemical techniques, bulk and destructive elemental analysis and surface and non-destructive XPS, were obtained. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  11. Voltammetry of ion transfer across a polarized room-temperature ionic liquid membrane facilitated by valinomycin: theoretical aspects and application.

    Science.gov (United States)

    Langmaier, Jan; Samec, Zdenek

    2009-08-01

    Cyclic voltammetry is used to investigate the transfer of alkali-metal cations, protons, and ammonium ions facilitated by the complex formation with valinomycin at the interface between an aqueous electrolyte solution and a room-temperature ionic liquid (RTIL) membrane. The membrane is made of a thin (approximately 112 microm) microporous filter impregnated with an RTIL that is composed of tridodecylmethylammonium cations and tetrakis[3,5-bis(trifluoromethyl)phenyl]borate anions. An extension of the existing theory of voltammetry of ion transfer across polarized liquid membranes makes it possible to evaluate the standard ion-transfer potentials for the hydrophilic cations studied, as well as the stability constants (K(i)) of their 1:1 complexes with valinomycin, as log K(i) = 9.0 (H(+)), 11.1 (Li(+)), 12.8 (Na(+)), 17.2 (K(+)), 15.7 (Rb(+)), 15.1 (Cs(+)), and 14.7 (NH(4)(+)). These data point to the remarkably enhanced stability of the valinomycin complexes within RTIL, and to the enhanced selectivity of valinomycin for K(+) over all other univalent ions studied, compared to the conventional K(+) ion-selective liquid-membrane electrodes. Selective complex formation allows one to resolve voltammetric responses of K(+) and Na(+) in the presence of an excess of Mg(2+) or Ca(2+), which is demonstrated by determination of K(+) and Na(+) in the table and tap water samples.

  12. Multi-podant diglycolamides and room temperature ionic liquid impregnated resins: An excellent combination for extraction chromatography of actinides.

    Science.gov (United States)

    Gujar, R B; Ansari, S A; Verboom, W; Mohapatra, P K

    2016-05-27

    Extraction chromatography resins, prepared by impregnating two multi-podant diglycolamide ligands, viz. diglycolamide-functionalized calix[4]arene (C4DGA) and tripodal diglycolamide (T-DGA) dissolved in the room temperature ionic liquid 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)amide (RTIL: C4mimTf2N) on Chromosorb-W (an inert solid support), gave excellent results for the removal of trivalent actinides from acidic waste solutions. Distribution coefficient measurements on several metal ions showed selective sorption of Am(III) over hexavalent uranyl ions and other fission product elements such as strontium and cesium. The sorbed metal ions could be efficiently desorbed with a complexing solution containing guanidine carbonate and EDTA buffer. The sorption of Am(III) on both resins followed pseudo-second order rate kinetics with rate constants of 1.37×10(-6) and 6.88×10(-7)g/cpmmin for T-DGA and C4DGA resins, respectively. The metal sorption on both resins indicated the Langmuir monolayer chemisorption phenomenon with Eu(III) sorption capacities of 4.83±0.21 and 0.52±0.05mg per g of T-DGA and C4DGA resins, respectively. The results of column studies show that these resins are of interest for a possible application for the recovery of hazardous trivalent actinides from dilute aqueous solutions. Copyright © 2016 Elsevier B.V. All rights reserved.

  13. Electronic temperature control and measurements reactor fuel rig circuits

    Energy Technology Data Exchange (ETDEWEB)

    Glowacki, S W

    1980-01-01

    The electronic circuits of two digital temperature meters developed for the thermocouple of Ni-NiCr type are described. The output thermocouple signal as converted by means of voltage-to-freguency converter. The frequency is measured by a digital scaler controled by quartz generator signals. One of the described meter is coupled with digital temperature controler which drives the power stage of the reactor rig heater. The internal rig temperature is measured by the thermocouple providing the input signal to the mentioned voltage-to-frequency converter, that means the circuits work in the negative feedback loop. The converter frequency-to-voltage ratio is automatically adjusted to match to thermocouple sensitivity changes in the course of the temperature variations. The accuracy of measuring system is of order of +- 1degC for thermocouple temperature changes from 523 K up to 973 K (50degC up to 700degC).

  14. The electronic temperature control and measurements reactor fuel rig circuits

    International Nuclear Information System (INIS)

    Glowacki, S.W.

    1980-01-01

    The electronic circuits of two digital temperature meters developed for the thermocouple of Ni-NiCr type are described. The output thermocouple signal as converted by means of voltage-to-freguency converter. The frequency is measured by a digital scaler controled by quartz generator signals. One of the described meter is coupled with digital temperature controler which drives the power stage of the reactor rig heater. The internal rig temperature is measured by the thermocouple providing the input signal to the mentioned voltage-to-frequency converter, that means the circuits work in the negative feedback loop. The converter frequency-to-voltage ratio is automatically adjusted to match to thermocouple sensitivity changes in the course of the temperature variations. The accuracy of measuring system is of order of +- 1degC for thermocouple temperature changes from 523 K up to 973 K (50degC up to 700degC). (author)

  15. Effect of re-heating on the hot electron temperature

    International Nuclear Information System (INIS)

    Estabrook, K.; Rosen, M.

    1980-01-01

    Resonant absorption is the direct conversion of the transverse laser light to longitudinal electron plasma waves (epw) at the critical density [10 21 (1.06 μm/lambda 0 ) 2 cm -3 ]. The oscillating longitudinal electric field of the epw heats the electrons by accelerating them down the density gradient to a temperature of approximately 21T/sub e/ 0 25 ([I(W/cm 2 )/10 16 ](lambda 0 /1.06 μm) 2 ) 0 4 . This section extends the previous work by studying the effects of magnetic fields and collisions (albedo) which return the heated electrons for further heating. A magnetic field increases their temperature and collisions do not

  16. Collisional drift waves in a plasma with electron temperature inhomogeneity

    International Nuclear Information System (INIS)

    Drake, J.F.; Hassam, A.B.

    1981-01-01

    A fluid theory of collisional electrostatic drift waves in a plasma slab with magnetic shear is presented. Both electron temperature and density gradients are included. The equations are solved analytically in all relevant regions of the parameter space defined by the magnetic shear strength and the perpendicular wavelength and explicit expressions for the growth rates are given. For shear strengths appropriate for present-day tokamak discharges the temperature gradient produces potential wells which localize the mode in the electron resistive region, well inside the ion sound turning points. Mode stability arises from a competition between the destabilizing influence of the time dependent thermal force and the stabilizing influence of electron energy dissipation. Convective energy loss is not important for shear parameters of present-day fusion devices

  17. Neutron scattering experiments of the ionic crystal deformed plastically with uniaxial compression under high temperature

    Energy Technology Data Exchange (ETDEWEB)

    Tsuchiya, Yoshinori; Minakawa, Nobuaki; Aizawa, Kazuya; Ozawa, Kunio [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1996-04-01

    As an aim of huge growth of alkali halide (AH) single crystal, a mosaic structure of small size AH single crystal deformed plastically with uniaxial compression under high temperature was evaluated due to its neutron irradiation experiment. Using TAS-2 installed at JRR-3M guide hole of Japan Atomic Energy Research Institute, locking curve at a representative face factor of the specimen was measured to observe the mosaic structure accompanied with expansion of the crystal due to compression. As a result, though the specimen before compression could be supposed to be divided to some parts already, the locking curve under 10 sec. of compression time showed already some fracture to divisions to suppose finer degradation of the crystal, and division of the locking curve at 600 sec. of compression time could be observed onto its 220 face. And, every compressed specimens showed some changes of crystallization method from standard sample. (G.K.)

  18. Electron temperature in the E-region of the ionosphere

    International Nuclear Information System (INIS)

    Zalpuri, K.S.; Oyama, K.-I.

    1991-06-01

    Various heating and cooling mechanisms which are operative in the lower E-region are discussed and their relative importance in different altitude range is shown. These heating and cooling rates are then used to derive the electron temperature T e . The calculated values of electron temperature are found to be higher than neutral temperature through out the altitude range 100 ∼ 150 km, with the difference increasing with increase in altitude. However, compared to observed values of T e , the calculated values are still smaller below about 130 km. Above this altitude, the calculated values become larger. Estimation of T e for different, suggested values of heating efficiency due to dissociative recombination, show that T e profile obtained even be assuming a constant value of 1.3 eV is in fairly good agreement with those derived based on variable values of this parameter. (author)

  19. Quantitative Analysis of Piroxicam Using Temperature-Controlled Ionic Liquid Dispersive Liquid Phase Microextraction Followed By Stopped-Flow Injection Spectrofluorimetry

    Directory of Open Access Journals (Sweden)

    Mohammad Reza Ganjali

    2013-07-01

    Full Text Available Background:Piroxicam (PXM belongs to the wide class of non-steroidal anti-inflammatory drugs (NSAIDs. PXM has been widely applied in the treatment of rheumatoid arthritis, gonarthrosis, osteoarthritis, backaches, neuralgia, mialgia. In the presented work, a green and benign sample pretreatment method called temperature-controlled ionic liquid dispersive liquid phase microextraction (TCIL-DLPME was followed with stopped-flow injection spectrofluorimetry (SFIS for quantitation of PXM in pharmaceutical formulations and biological samples.Methods:Temperature-controlled ionic liquid dispersive liquid phase microextraction (TCIL-DLPME was applied as an environmentally friendly sample enrichment method to extract and isolate PXM prior to quantitation. Dispersion of 1-hexyl-3-methylimidazolium hexafluorophosphate ([Hmim][PF6] ionic liquid (IL through the sample aqueous solution was performed by applying a relatively high temperature. PXM was extracted into the extractor, and after phase separation, PXM in the final solution was determined by stopped-flow injection spectrofluorimetry (SFIS.Results and Major Conclusion:Different factors affecting the designed method such as IL amount, diluting agent, pH and temperature were investigated in details and optimized. The method provided a linear dynamic range of 0.2-150 μg l-1, a limit of detection (LOD of 0.046 μg l-1 and a relative standard deviation (RSD of 3.1%. Furthermore, in order to demonstrate the analytical applicability of the recommended method, it was applied for quantitation of PXM in real samples.

  20. A study on the swelling characteristics of a potential buffer material : Effect of ionic strength and temperature on the swelling pressure

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jae Owan; Cho, Won Jin; Chun, Kwan Sik [Korea Atomic Energy Research Institute, Taejon (Korea)

    1999-04-01

    This study is intended to investigate the effect of ionic strength and temperature on the swelling pressure of bentonite. The dry density for compacted bentonite was adjusted between 1.4 Mg/m{sup 3} - 1.8 Mg/m{sup 3}. The effect of temperature was tested at 20 deg C, 40 deg C, 60 deg C, 80 deg C, and the effect of ionic strength with distilled water, synthetic ground water, and 0.01 M - 0.1 M NaCl solution. The swelling pressure decreased with increasing ionic strength, and its dependency got lower at high dry density. Temperature had negligible effect on the swelling pressure of compacted bentonite, which could be explained by the change in hydration pressure, osmotic pressure, and pore water pressure in accordance with temperature. The swelling pressure of compacted bentonite with low dry density was dominated mainly by osmosis. However, hydration was thought to become important at higher dry density, compared with the osmosis. 32 refs., 11 figs., 4 tabs. (Author)

  1. Electronic and ionic conductivity studies on microwave synthesized glasses containing transition metal ions

    Directory of Open Access Journals (Sweden)

    Basareddy Sujatha

    2017-01-01

    Full Text Available Glasses in the system xV2O5·20Li2O·(80 − x [0.6B2O3:0.4ZnO] (where 10 ≤ x ≤ 50 have been prepared by a simple microwave method. Microwave synthesis of materials offers advantages of efficient transformation of energy throughout the volume in an effectively short time. Conductivity in these glasses was controlled by the concentration of transition metal ion (TMI. The dc conductivity follows Arrhenius law and the activation energies determined by regression analysis varies with the content of V2O5 in a non-linear passion. This non-linearity is due to different conduction mechanisms operating in the investigated glasses. Impedance and electron paramagnetic resonance (EPR spectroscopic studies were performed to elucidate the nature of conduction mechanism. Cole–cole plots of the investigated glasses consist of (i single semicircle with a low frequency spur, (ii two depressed semicircles and (iii single semicircle without spur, which suggests the operation of two conduction mechanisms. EPR spectra reveal the existence of electronic conduction between aliovalent vanadium sites. Further, in highly modified (10V2O5 mol% glasses Li+ ion migration dominates.

  2. Influence of hydroxyl group position and temperature on thermophysical properties of tetraalkylammonium hydroxide ionic liquids with alcohols.

    Directory of Open Access Journals (Sweden)

    Pankaj Attri

    Full Text Available In this work, we have explored the thermophysical properties of tetraalkylammonium hydroxide ionic liquids (ILs such as tetrapropylammonium hydroxide (TPAH and tetrabutylammonium hydroxide (TBAH with isomers of butanol (1-butanol, 2-butanol and 2-methyl-2-propanol within the temperature range 293.15-313.15 K, with interval of 5 K and over the varied concentration range of ILs. The molecular interactions between ILs and butanol isomers are essential for understanding the function of ILs in related measures and excess functions are sensitive probe for the molecular interactions. Therefore, we calculated the excess molar volume (V(E and the deviation in isentropic compressibility (Δκs using the experimental values such as densities (ρ and ultrasonic sound velocities (u that are measured over the whole compositions range at five different temperatures (293.15, 298.15, 303.15, 308.15 and 313.15 K and atmospheric pressure. These excess functions were adequately correlated by using the Redlich-Kister polynomial equation. It was observed that for all studied systems, the V(E and Δκs values are negative for the whole composition range at 293.15 K. And, the excess function follows the sequence: 2-butanol>1-butanol>2-methyl-2-propanol, which reveals that (primary or secondary or tertiary position of hydroxyl group influence the magnitude of interactions with ILs. The negative values of excess functions are contributions from the ion-dipole interaction, hydrogen bonding and packing efficiency between the ILs and butanol isomers. Hence, the position of hydroxyl group plays an important role in the interactions with ILs. The hydrogen bonding features between ILs and alcohols were analysed using molecular modelling program by using HyperChem 7.

  3. Influence of hydroxyl group position and temperature on thermophysical properties of tetraalkylammonium hydroxide ionic liquids with alcohols.

    Science.gov (United States)

    Attri, Pankaj; Baik, Ku Youn; Venkatesu, Pannuru; Kim, In Tae; Choi, Eun Ha

    2014-01-01

    In this work, we have explored the thermophysical properties of tetraalkylammonium hydroxide ionic liquids (ILs) such as tetrapropylammonium hydroxide (TPAH) and tetrabutylammonium hydroxide (TBAH) with isomers of butanol (1-butanol, 2-butanol and 2-methyl-2-propanol) within the temperature range 293.15-313.15 K, with interval of 5 K and over the varied concentration range of ILs. The molecular interactions between ILs and butanol isomers are essential for understanding the function of ILs in related measures and excess functions are sensitive probe for the molecular interactions. Therefore, we calculated the excess molar volume (V(E) ) and the deviation in isentropic compressibility (Δκs ) using the experimental values such as densities (ρ) and ultrasonic sound velocities (u) that are measured over the whole compositions range at five different temperatures (293.15, 298.15, 303.15, 308.15 and 313.15 K) and atmospheric pressure. These excess functions were adequately correlated by using the Redlich-Kister polynomial equation. It was observed that for all studied systems, the V(E) and Δκs values are negative for the whole composition range at 293.15 K. And, the excess function follows the sequence: 2-butanol>1-butanol>2-methyl-2-propanol, which reveals that (primary or secondary or tertiary) position of hydroxyl group influence the magnitude of interactions with ILs. The negative values of excess functions are contributions from the ion-dipole interaction, hydrogen bonding and packing efficiency between the ILs and butanol isomers. Hence, the position of hydroxyl group plays an important role in the interactions with ILs. The hydrogen bonding features between ILs and alcohols were analysed using molecular modelling program by using HyperChem 7.

  4. Influence of alkyl chain length and temperature on thermophysical properties of ammonium-based ionic liquids with molecular solvent.

    Science.gov (United States)

    Kavitha, T; Attri, Pankaj; Venkatesu, Pannuru; Devi, R S Rama; Hofman, T

    2012-04-19

    Mixing of ionic liquids (ILs) with molecular solvent can expand the range of structural properties and the scope of molecular interactions between the molecules of the solvents. Exploiting of these phenomena essentially require a basic fundamental understanding of mixing behavior of ILs with molecular solvents. In this context, a series of protic ILs possessing tetra-alkyl ammonium cation [R(4)N](+) with commonly used anion hydroxide [OH](-) were synthesized and characterized by temperature dependent thermophysical properties. The ILs [R(4)N](+)[OH](-) are varying only in the length of alkyl chain (R is methyl, ethyl, propyl, or butyl) of tetra-alkyl ammonium on the cationic part. The ILs used for the present study included tetramethyl ammonium hydroxide [(CH(3))(4)N](+)[OH](-) (TMAH), tetraethyl ammonium hydroxide [(C(2)H(5))(4)N](+)[OH](-) (TEAH), tetrapropyl ammonium hydroxide [(C(3)H(7))(4)N](+)[OH](-) (TPAH) and tetrabutyl ammonium hydroxide [(C(4)H(9))(4)N](+)[OH](-) (TBAH). The alkyl chain length effect has been analyzed by precise measurements such as densities (ρ), ultrasonic sound velocity (u), and viscosity (η) of these ILs with polar solvent, N-methyl-2-pyrrolidone (NMP), over the full composition range as a function of temperature. The excess molar volume (V(E)), the deviation in isentropic compressibility (Δκ(s)) and deviation in viscosity (Δη) were predicted using these properties as a function of the concentration of ILs. Redlich-Kister polynomial was used to correlate the results. A qualitative analysis of the results is discussed in terms of the ion-dipole, ion-pair interactions, and hydrogen bonding between ILs and NMP molecules. Later, the hydrogen bonding features between ILs and NMP were also analyzed using a molecular modeling program with the help of HyperChem 7.

  5. Novel room temperature ionic liquid for fluorescence enhancement of Eu{sup 3+} and Tb{sup 3+}

    Energy Technology Data Exchange (ETDEWEB)

    Shyamala Devi, V.; Maji, S. [Materials Chemistry Division, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102 (India); Viswanathan, K.S., E-mail: vish@igcar.gov.i [Materials Chemistry Division, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102 (India)

    2011-04-15

    The newly prepared ionic liquid, 1-butyl-3-methylimidazolium benzoate, ([bmim][BA]), was found to enhance the fluorescence of Eu{sup 3+} and Tb{sup 3+}. The fluorescence enhancement resulted from a sensitization of the lanthanide fluorescence by the benzoate anion of the ionic liquid, [bmim][BA], and a reduction in the non-radiative channels in the non-aqueous environment provided by the ionic liquid. However, the fluorescence enhancement of the lanthanides in the ionic liquid was limited due to the operation of the inner filter effect, which resulted from the strong absorption of the benzoate. The inner filter effect was minimized by observing the Eu{sup 3+} fluorescence using a front face geometry and also by diluting the lanthanide-[bmim][BA]system, using another ionic liquid, 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([bmim][Tf{sub 2}N]), as a solvent. In the case of Tb{sup 3+}, the emission from the lanthanide was masked by the strong emission from the ionic liquid in the region 450-580 nm. The long lived Tb{sup 3+} emission was therefore observed using delayed gated detection, where an appropriate delay was used to discriminate against the short lived emission from the ionic liquid. The large fluorescence enhancement due to ligand sensitized fluorescence observed with [bmim][BA]diluted in [bmim][Tf{sub 2}N], leads to nanomolar detection of the lanthanides. This is, to the best of our knowledge, the first report of an ionic liquid being employed for ligand sensitized fluorescence enhancement of lanthanides. - Research highlights: {yields}The use of an ionic liquid to enhance the fluorescence of lanthanides, Eu{sup 3+} and Tb{sup 3+} is discussed in this paper. {yields} This study represents the first report of the use of a tailored ionic liquid for the purposes of fluorescence enhancement. {yields} The fluorescence enhancement is achieved both a process of ligand sensitization, as well as reducing the non-radiative decay channels. {yields

  6. Continuous Emission Spectrum Measurement for Electron Temperature Determination in Low-Temperature Collisional Plasmas

    International Nuclear Information System (INIS)

    Liu Qiuyan; Li Hong; Chen Zhipeng; Xie Jinlin; Liu Wandong

    2011-01-01

    Continuous emission spectrum measurement is applied for the inconvenient diagnostics of low-temperature collisional plasmas. According to the physical mechanism of continuous emission, a simplified model is presented to analyze the spectrum in low temperature plasma. The validity of this model is discussed in a wide range of discharge parameters, including electron temperature and ionization degree. Through the simplified model, the continuous emission spectrum in a collisional argon internal inductively coupled plasma is experimentally measured to determine the electron temperature distribution for different gas pressures and radio-frequency powers. The inverse Abel transform is also applied for a better spatially resoluted results. Meanwhile, the result of the continuous emission spectrum measurement is compared to that of the electrostatic double probes, which indicates the effectiveness of this method. (low temperature plasma)

  7. Role of a non-ionic surfactant in direct electron transfer-type bioelectrocatalysis by fructose dehydrogenase

    International Nuclear Information System (INIS)

    Kawai, Shota; Yakushi, Toshiharu; Matsushita, Kazunobu; Kitazumi, Yuki; Shirai, Osamu; Kano, Kenji

    2015-01-01

    Highlights: • Addition of Triton ® X-100 (1%) completely quenches the FDH-catalyzed current at hydrophobic electrode, but causes only small competitive effect at hydrophilic electrode. • Quartz crystal microbalance measurements support the adsorption of FDH and Triton ® X-100 on both of the electrodes. • The surfactant forms a monolayer on the hydrophobic electrode and FDH adsorbs on the surfactant monolayer. • The surfactant forms a bilayer on the hydrophilic electrode and FDH is embedded in the bilayer to communicate with the electrode. - ABSTRACT: A heterotrimeric membrane-bound fructose dehydrogenase (FDH) from Gluconobacter japonicus NBRC3260 contains FAD in subunit I and three heme C moieties in subunit II as the redox centers, and is one of the direct electron transfer (DET)-type redox enzymes. FDH-catalyzed current density of fructose oxidation at hydrophilic mercaptoethanol (MEtOH)-modified Au electrode is much larger than that at hydrophobic mercaptoethane (MEtn)-modified Au electrode. Addition of a non-ionic surfactant Triton ® X-100 (1%) completely quenches the catalytic current at the MEtn-modified Au electrode, while only small competitive effect is observed at the MEtOH-modified Au electrode. Quartz crystal microbalance measurements support the adsorption of FDH and Triton ® X-100 on both of the modified electrodes. We propose a model to explain the phenomenon as follows. The surfactant forms a monolayer on the hydrophobic MEtn-modified electrode with strong hydrophobic interaction, and FDH adsorbs on the surface of the surfactant monolayer. The monolayer inhibits the electron transfer from FDH to the electrode. On the other hand, the surfactant forms a bilayer on the hydrophilic MEtOH-modified electrode. The interaction between the surfactant bilayer and the hydrophilic electrode is relatively weak so that FDH replaces the surfactant and is embedded in the bilayer to communicate electrochemically with the hydrophilic electrode

  8. Ionic effects on the temperature-force phase diagram of DNA.

    Science.gov (United States)

    Amnuanpol, Sitichoke

    2017-12-01

    Double-stranded DNA (dsDNA) undergoes a structural transition to single-stranded DNA (ssDNA) in many biologically important processes such as replication and transcription. This strand separation arises in response either to thermal fluctuations or to external forces. The roles of ions are twofold, shortening the range of the interstrand potential and renormalizing the DNA elastic modulus. The dsDNA-to-ssDNA transition is studied on the basis that dsDNA is regarded as a bound state while ssDNA is regarded as an unbound state. The ground state energy of DNA is obtained by mapping the statistical mechanics problem to the imaginary time quantum mechanics problem. In the temperature-force phase diagram the critical force F c (T) increases logarithmically with the Na + concentration in the range from 32 to 110 mM. Discussing this logarithmic dependence of F c (T) within the framework of polyelectrolyte theory, it inevitably suggests a constraint on the difference between the interstrand separation and the length per unit charge during the dsDNA-to-ssDNA transition.

  9. Relations between stellar mass and electron temperature-based metallicity for star-forming galaxies in a wide mass range

    International Nuclear Information System (INIS)

    Shi Wei-Bin; Zhao Gang; Ruan Gui-Ping; Zhou Li; Liang Yan-Chun; Shao Xu; Liu Xiao-Wei; Hammer Francois; Flores Hector; Zhang Yong

    2014-01-01

    We select 947 star-forming galaxies from SDSS-DR7 with [O III]λ4363 emission lines detected at a signal-to-noise ratio larger than 5σ. Their electron temperatures and direct oxygen abundances are then determined. We compare the results from different methods. t 2 , the electron temperature in the low ionization region, estimated from t 3 , that in the high ionization region, is compared using three analysis relations between t 2 – t 3 . These show obvious differences, which result in some different ionic oxygen abundances. The results of t 3 , t 2 , O ++ /H + and O + /H + derived by using methods from IRAF and literature are also compared. The ionic abundances O ++ /H + are higher than O + /H + for most cases. The different oxygen abundances derived from T e and the strong-line ratios show a clear discrepancy, which is more obvious following increasing stellar mass and strong-line ratio R 23 . The sample of galaxies from SDSS with detected [O III]λ4363 have lower metallicites and higher star formation rates, so they may not be typical representatives of the whole population of galaxies. Adopting data objects from Andrews and Martini, Liang et al. and Lee et al. data, we derive new relations of stellar mass and metallicity for star-forming galaxies in a much wider stellar mass range: from 10 6 M ⊙ to 10 11 M ⊙ . (research papers)

  10. Highly water-dispersible, mixed ionic-electronic conducting, polymer acid-doped polyanilines as ionomers for direct methanol fuel cells.

    Science.gov (United States)

    Murthy, Arun; Manthiram, Arumugam

    2011-06-28

    Highly water-dispersible polymer acid-doped polyanilines have been synthesized and evaluated as an alternative for expensive Nafion ionomers in the anode of direct methanol fuel cells (DMFC). These polymers as ionomers lead to higher performance in single cell DMFC compared to Nafion ionomers due to mixed ionic-electronic conduction, water dispersibility, and co-catalytic activity. This journal is © The Royal Society of Chemistry 2011

  11. Electronic structure of the high-temperature oxide superconductors

    International Nuclear Information System (INIS)

    Pickett, W.E.

    1989-01-01

    Since the discovery of superconductivity above 30 K by Bednorz and Mueller in the La copper oxide system, the critical temperature has been raised to 90 K in YBa 2 Cu 3 O 7 and to 110 and 125 K in Bi-based and Tl-based copper oxides, respectively. In the two years since this Nobel-prize-winning discovery, a large number of electronic structure calculations have been carried out as a first step in understanding the electronic properties of these materials. In this paper these calculations (mostly of the density-functional type) are gathered and reviewed, and their results are compared with the relevant experimental data. The picture that emerges is one in which the important electronic states are dominated by the copper d and oxygen p orbitals, with strong hybridization between them. Photon, electron, and positron spectroscopies provide important information about the electronic states, and comparison with electronic structure calculations indicates that, while many features can be interpreted in terms of existing calculations, self-energy corrections (''correlations'') are important for a more detailed understanding. The antiferromagnetism that occurs in some regions of the phase diagram poses a particularly challenging problem for any detailed theory. The study of structural stability, lattice dynamics, and electron-phonon coupling in the copper oxides is also discussed. Finally, a brief review is given of the attempts so far to identify interaction constants appropriate for a model Hamiltonian treatment of many-body interactions in these materials

  12. SPECTROSCOPIC DIAGNOSIS IN ELECTRONIC TEMPERATURE OF PHOTOIONISE PLASMAS

    Directory of Open Access Journals (Sweden)

    A. K. Ferouani

    2015-08-01

    Full Text Available In this work, we are interested in the diagnostics in electronic temperature of a plasma purely photoionized, based on the intensity ration of lines emitted by ions helium-like, which have an atomic number Z relatively small. We considered the three lines corresponding to the transitions starting from the excited levels 1s2l towards the fundamental level 1s2 1S0, like appropriate lines. More precisely, the line of resonance w due to the transition 1s2p 1P1 --- 1s2 1 S0, the line of intercombinaison (x,y 1s2p 3 P2,1 --- 1s2 1 S0  as well as prohibited line z due to the transition 1s2 3 S1 --- 1s2 1 S0. These lines appear clearly in the spectra of astrophysical plasmas. As helium-like ion, we chose two, the oxygen O6+ (Z=8 and neon Ne8+ (Z=10. We carried out calculations of the ration of lines intensity G=(z+x+y/w of O6+ and Ne8+  according to the electronic temperature in the range going from 105 to 107 K. We will see that, like it was shown by Gabriel and Jordan in 1969 [1], this intensity ration can be very sensitive to the temperature electronic and practically independent of the electronic density. Consequently, the ration G can be used to determine in a reliable way the electronic temperature of plasma observed [2].

  13. Low temperature electron microscopy and electron diffraction of the purple membrane of Halobacterium halobium

    International Nuclear Information System (INIS)

    Hayward, S.B.

    1978-09-01

    The structure of the purple membrane of Halobacterium halobium was studied by high resolution electron microscopy and electron diffraction, primarily at low temperature. The handedness of the purple membrane diffraction pattern with respect to the cell membrane was determined by electron diffraction of purple membranes adsorbed to polylysine. A new method of preparing frozen specimens was used to preserve the high resolution order of the membranes in the electron microscope. High resolution imaging of glucose-embedded purple membranes at room temperature was used to relate the orientation of the diffraction pattern to the absolute orientation of the structure of the bacteriorhodopsin molecule. The purple membrane's critical dose for electron beam-induced damage was measured at room temperature and at -120 0 C, and was found to be approximately five times greater at -120 0 C. Because of this decrease in radiation sensitivity, imaging of the membrane at low temperature should result in an increased signal-to-noise ratio, and thus better statistical definition of the phases of weak reflections. Higher resolution phases may thus be extracted from images than can be determined by imaging at room temperature. To achieve this end, a high resolution, liquid nitrogen-cooled stage was built for the JEOL-100B. Once the appropriate technology for taking low dose images at very high resolution has been developed, this stage will hopefully be used to determine the high resolution structure of the purple membrane

  14. Efficient removal of H2S at high temperature using the ionic liquid solutions of [C4mim]3PMo12O40-An organic polyoxometalate.

    Science.gov (United States)

    Ma, Yunqian; Liu, Xinpeng; Wang, Rui

    2017-06-05

    An innovative approach to H 2 S capture and sulfur recovery via liquid redox at high temperature has been developed using [C 4 mim] 3 PMo 12 O 40 at temperatures ranging from 80 to 180°C, which is superior to the conventional water-based system with an upper limit of working temperature normally below 60°C. The ionic liquids used as solvents include [C 4 mim]Cl, [C 4 mim]BF 4 , [C 4 mim]PF 6 and [C 4 mim]NTf 2 . Microscopic observation and turbidity measurement were used to investigate the dissolution of [C 4 mim] 3 PMo 12 O 40 in the ionic liquids. Stabilization energy between H 2 S and the anion of ionic liquid as well as H 2 O was calculated to illustrate the interaction between H 2 S and the solvents. The cavity theory can be adopted to illustrate the mechanism for H 2 S absorption: the Cl - ion with small radius can be incorporated into the cavities of [C 4 mim] 3 PMo 12 O 40 , and interact with H 2 S strongly. The underlying mechanism for sulfur formation is the redox reaction between H 2 S and PMo 12 O 40 3- . H 2 S can be oxidized to elemental sulfur and Mo 6+ is partly reduced during absorption, according to UV-vis and FTIR spectra. The [C 4 mim] 3 PMo 12 O 40 -[C 4 mim]Cl after reaction can be readily regenerated by air and thus enabling its efficient and repeatitive use. The absorbent of [C 4 mim] 3 PMo 12 O 40 -ionic liquid system provides a new approach for wet oxidation desulfurization at high temperature. Copyright © 2017 Elsevier B.V. All rights reserved.

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

    DEFF Research Database (Denmark)

    Cheng, Shiyang; Chatzichristodoulou, Christodoulos; Søgaard, Martin

    2017-01-01

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

  16. Electron excitation coefficients of neutral and ionic levels of krypton in Townsend discharges

    International Nuclear Information System (INIS)

    Malovic, G.N.; Strinic, A.I.; Petrovic, Z.Lj.; Sadeghi, N.

    2006-01-01

    In this paper, we present experimental results for excitation coefficients of krypton atoms to several Kr and Kr + excited levels for E/N (electric field to gas particle number density ratio usually in units of Townsend, 1 Td = 10 -21 V m 2 ) values from 7 x 10 -20 V m 2 to above 1 x 10 -17 V m 2 . The data have been obtained in two different parallel plate self-sustained Townsend discharge drift tubes. The spatial distribution of the emission intensities were recorded and then normalized to give excitation coefficients at the anode, by using the electron flux at this point. The values of these coefficients are placed on an absolute scale by using a standard tungsten ribbon lamp calibrated against a primary blackbody radiation standard. The ionization rates at different E/N are obtained from the spatial emission profiles. The data for atomic krypton levels 2p 2 , 2p 3 , 2p 5 , 2p 6 , 2p 7 , 2p 8 , 3p 5 and 3p 6 (in Paschen notation) were converted to excitation coefficients by using quenching coefficients from the literature. The emission coefficients of eight 4s 2 4p 4 ( 3 P)5p levels of Kr + have also been measured for E/N values from about 1 x 10 -18 V m 2 up to nearly 8 x 10 -18 V m 2

  17. Electron temperature diagnostics in the RFX reversed field pinch experiment

    International Nuclear Information System (INIS)

    Bartiromo, R.; Carraro, L.; Marrelli, L.; Murari, A.; Pasqualotto, R.; Puiatti, M.E.; Scarin, P.; Valisa, M.; Franz, P.; Martin, P.; Zabeo, L.

    2000-01-01

    The paper presents an integrated approach to the problem of electron temperature diagnostics of the plasma in a reversed field pinch. Three different methods, sampling different portions of the electron distribution function, are adopted, namely Thomson scattering, soft X-ray spectroscopy by pulse-height analysis and filtered soft X-ray intensity ratio. A careful analysis of the different sources of systematic errors is performed and a novel statistical approach is adopted to mutually validate the three independent measurements. A satisfactory agreement is obtained over a large range of experimental conditions, indicating that in the plasma core the energy distribution function is well represented by a maxwellian. (author)

  18. Electron temperature measurements in lowdensity plasmas by helium spectroscopy

    International Nuclear Information System (INIS)

    Brenning, N.

    1977-09-01

    This method to use relative intensities of singlet and triplet lines of neutral helium to measure electron temperature in low-density plasmas is examined. Calculations from measured and theoretical data about transitions in neutral helium are carried out and compared to experimental results. It is found that relative intensities of singlet and triplet lines from neutral helium only can be used for TE determination in low-density, short-duration plasmas. The most important limiting processes are excitation from the metastable 2 3 S level and excitation transfer in collisions between electrons and excited helium atoms. An evaluation method is suggested, which minimizes the effect of these processes. (author)

  19. Electron-beam damaged high-temperature superconductor Josephson junctions

    International Nuclear Information System (INIS)

    Pauza, A.J.; Booij, W.E.; Herrmann, K.; Moore, D.F.; Blamire, M.G.; Rudman, D.A.; Vale, L.R.

    1997-01-01

    Results are presented on the fabrication and characterization of high critical temperature Josephson junctions in thin films of YBa 2 Cu 3 O 7-δ produced by the process of focused electron-beam irradiation using 350 keV electrons. The junctions so produced have uniform spatial current densities, can be described in terms of the resistive shunted junction model, and their current densities can be tailored for a given operating temperature. The physical properties of the damaged barrier can be described as a superconducting material of either reduced or zero critical temperature (T c ), which has a length of ∼15nm. The T c reduction is caused primarily by oxygen Frenkel defects in the Cu - O planes. The large beam currents used in the fabrication of the junctions mean that the extent of the barrier is limited by the incident electron-beam diameter, rather than by scattering within the film. The properties of the barrier can be calculated using a superconductor/normal/superconductor (SNS) junction model with no boundary resistance. From the SNS model, we can predict the scaling of the critical current resistance (I c R n ) product and gain insight into the factors controlling the junction properties, T c , and reproducibility. From the measured I c R n scaling data, we can predict the I c R n product of a junction at a given operating temperature with a given current density. I c R n products of ∼2mV can be achieved at 4.2 K. The reproducibility of several junctions in a number of samples can be characterized by the ratio of the maximum-to-minimum critical currents on the same substrate of less than 1.4. Stability over several months has been demonstrated at room and refrigerator temperatures (297 and 281 K) for junctions that have been initially over damaged and then annealed at temperatures ∼380K. (Abstract Truncated)

  20. State of the art of High Temperature Power Electronics

    OpenAIRE

    Buttay , Cyril; Planson , Dominique; Allard , Bruno; Bergogne , Dominique; Bevilacqua , Pascal; Joubert , Charles; Lazar , Mihai; Martin , Christian; Morel , Hervé; Tournier , Dominique; Raynaud , Christophe

    2009-01-01

    International audience; High temperature power electronics has become possible with the recent availability of silicon carbide devices. This material, as other wide-bandgap semiconductors, can operate at temperatures above 500°C, whereas silicon is limited to 150-200°C. Applications such as transportation or deep oil and gas wells drilling can benefit. A few converters operating above 200°C have been demonstrated, but work is still ongoing to design and build a power system able to operate in...

  1. Temperature distribution induced by electron beam in a closed cavity

    International Nuclear Information System (INIS)

    Molhem, A.G.; Soulayman, S.Sh.

    2004-01-01

    In order to investigate heat transfer phenomena induced by EB in a closed cavity an experimental arrangement, which allows generating and focusing an electron beam in to closed cavity within 1 mm in diameter and measuring temperature all over any perpendicular section to the EB, is used for this purpose. Experimental data show that the radial distribution of current density and temperature is normal with pressure and location dependent parameters. Moreover, there is two distinguishable regions in the EB: one is central while the other surrounds the first one. (orig.)

  2. Ferromagnetism and temperature-dependent electronic structure in metallic films

    International Nuclear Information System (INIS)

    Herrmann, T.

    1999-01-01

    In this work the influence of the reduced translational symmetry on the magnetic properties of thin itinerant-electron films and surfaces is investigated within the strongly correlated Hubbard model. Firstly, the possibility of spontaneous ferromagnetism in the Hubbard model is discussed for the case of systems with full translational symmetry. Different approximation schemes for the solution of the many-body problem of the Hubbard model are introduced and discussed in detail. It is found that it is vital for a reasonable description of spontaneous ferromagnetism to be consistent with exact results concerning the general shape of the single-electron spectral density in the limit of strong Coulomb interaction between the electrons. The temperature dependence of the ferromagnetic solutions is discussed in detail by use of the magnetization curves as well as the spin-dependent quasi particle spectrum. For the investigation of thin films and surfaces the approximation schemes for the bulk system have to be generalized to deal with the reduced translational symmetry. The magnetic behavior of thin Hubbard films is investigated by use of the layer dependent magnetization as a function of temperature as well as the thickness of the film. The Curie-temperature is calculated as a function of the film thickness. Further, the magnetic stability at the surface is discussed in detail. Here it is found that for strong Coulomb interaction the magnetic stability at finite temperatures is reduced at the surface compared to the inner layers. This observation clearly contradicts the well-known Stoner picture of band magnetism and can be explained in terms of general arguments which are based on exact results in the limit of strong Coulomb interaction. The magnetic behavior of the Hubbard films can be analyzed in detail by inspecting the local quasi particle density of states as well as the wave vector dependent spectral density. The electronic structure is found to be strongly spin

  3. Structural and interactional behaviour of aqueous mixture of room temperature ionic liquid; 2-hydroxyethyl-trimethylammonium L-lactate

    International Nuclear Information System (INIS)

    Chaudhary, Ganga Ram; Bansal, Shafila; Mehta, S.K.; Ahluwalia, A.S.

    2014-01-01

    Highlights: • Thermophysical and spectroscopic properties of aqueous mixtures 2-[HE3MA]LAC have been measured. • Effect of temperature on thermophysical properties has also been studied. • Stronger intermolecular have been observed between [HE3MA]LAC and H 2 O. • Magnitude of interactions decreases with the rise in temperature. • Spectroscopic studies shows interactions between -N + -(CH 3 ) 3 with -OH - group and COO − with -H + of IL and H 2 O. - Abstract: In order to understand the molecular interactions between the green solvent system, (water + lactate based ionic liquid); 2-hydroxyethyl-trimethylammonium L-lactate ([(C 2 H 4 OH)(CH 3 ) 3 N][Lactate]), the thermophysical properties viz. density ρ, speed of sound u, specific conductivity κ, refractive index n D and spectroscopic properties viz. IR, 1 H and 13 C NMR have been investigated over the whole composition range at atmospheric pressure with temperature varied from (293.15 to 323.15) K. To gain more insight of intermolecular interactions occurring in the aqueous mixture of [(C 2 H 4 OH)(CH 3 ) 3 N][Lactate], intermolecular free length L f , acoustic impedance Z, relative association R A , excess molar volume V E , deviations in isentropic compressibility ΔK S , partial molar excess volume V i E , partial molar deviations in isentropic compressibility ΔK S,i , deviation in specific conductivity Δκ and deviation in refractive index Δn D have been predicted as a function of IL concentration over the whole composition range. These results have been fitted to the Redlich–Kister polynomial. A large deviation from ideality has been observed on mixing water and [(C 2 H 4 OH)(CH 3 ) 3 N][Lactate] which are due to the formation of strong intermolecular hydrogen bonding between the two molecules. Also, it has been noticed that the mixture of water and [(C 2 H 4 OH)(CH 3 ) 3 N][Lactate] became warm that indicates mixing of these two components is exothermic. Thermodynamic and spectroscopic data

  4. Effects of electrons on the solar wind proton temperature anisotropy

    International Nuclear Information System (INIS)

    Michno, M. J.; Lazar, M.; Schlickeiser, R.; Yoon, P. H.

    2014-01-01

    Among the kinetic microinstabilities, the firehose instability is one of the most efficient mechanisms to restrict the unlimited increase of temperature anisotropy in the direction of an ambient magnetic field as predicted by adiabatic expansion of collision-poor solar wind. Indeed, the solar wind proton temperature anisotropy detected near 1 AU shows that it is constrained by the marginal firehose condition. Of the two types of firehose instabilities, namely, parallel and oblique, the literature suggests that the solar wind data conform more closely to the marginal oblique firehose condition. In the present work, however, it is shown that the parallel firehose instability threshold is markedly influenced by the presence of anisotropic electrons, such that under some circumstances, the cumulative effects of both electron and proton anisotropies could describe the observation without considering the oblique firehose mode.

  5. High Temperature Wireless Communication And Electronics For Harsh Environment Applications

    Science.gov (United States)

    Hunter, G. W.; Neudeck, P. G.; Beheim, G. M.; Ponchak, G. E.; Chen, L.-Y

    2007-01-01

    In order for future aerospace propulsion systems to meet the increasing requirements for decreased maintenance, improved capability, and increased safety, the inclusion of intelligence into the propulsion system design and operation becomes necessary. These propulsion systems will have to incorporate technology that will monitor propulsion component conditions, analyze the incoming data, and modify operating parameters to optimize propulsion system operations. This implies the development of sensors, actuators, and electronics, with associated packaging, that will be able to operate under the harsh environments present in an engine. However, given the harsh environments inherent in propulsion systems, the development of engine-compatible electronics and sensors is not straightforward. The ability of a sensor system to operate in a given environment often depends as much on the technologies supporting the sensor element as the element itself. If the supporting technology cannot handle the application, then no matter how good the sensor is itself, the sensor system will fail. An example is high temperature environments where supporting technologies are often not capable of operation in engine conditions. Further, for every sensor going into an engine environment, i.e., for every new piece of hardware that improves the in-situ intelligence of the components, communication wires almost always must follow. The communication wires may be within or between parts, or from the engine to the controller. As more hardware is added, more wires, weight, complexity, and potential for unreliability is also introduced. Thus, wireless communication combined with in-situ processing of data would significantly improve the ability to include sensors into high temperature systems and thus lead toward more intelligent engine systems. NASA Glenn Research Center (GRC) is presently leading the development of electronics, communication systems, and sensors capable of prolonged stable

  6. Screen-Printed Graphite Electrodes as Low-Cost Devices for Oxygen Gas Detection in Room-Temperature Ionic Liquids.

    Science.gov (United States)

    Lee, Junqiao; Hussain, Ghulam; Banks, Craig E; Silvester, Debbie S

    2017-11-26

    Screen-printed graphite electrodes (SPGEs) have been used for the first time as platforms to detect oxygen gas in room-temperature ionic liquids (RTILs). Up until now, carbon-based SPEs have shown inferior behaviour compared to platinum and gold SPEs for gas sensing with RTIL solvents. The electrochemical reduction of oxygen (O₂) in a range of RTILs has therefore been explored on home-made SPGEs, and is compared to the behaviour on commercially-available carbon SPEs (C-SPEs). Six common RTILs are initially employed for O₂ detection using cyclic voltammetry (CV), and two RTILs ([C₂mim][NTf₂] and [C₄mim][PF₆]) chosen for further detailed analytical studies. Long-term chronoamperometry (LTCA) was also performed to test the ability of the sensor surface for real-time gas monitoring. Both CV and LTCA gave linear calibration graphs-for CV in the 10-100% vol. range, and for LTCA in the 0.1-20% vol. range-on the SPGE. The responses on the SPGE were far superior to the commercial C-SPEs; more instability in the electrochemical responses were observed on the C-SPEs, together with some breaking-up or dissolution of the electrode surface materials. This study highlights that not all screen-printed ink formulations are compatible with RTIL solvents for longer-term electrochemical experiments, and that the choice of RTIL is also important. Overall, the low-cost SPGEs appear to be promising platforms for the detection of O₂, particularly in [C₄mim][PF₆].

  7. Screen-Printed Graphite Electrodes as Low-Cost Devices for Oxygen Gas Detection in Room-Temperature Ionic Liquids

    Directory of Open Access Journals (Sweden)

    Junqiao Lee

    2017-11-01

    Full Text Available Screen-printed graphite electrodes (SPGEs have been used for the first time as platforms to detect oxygen gas in room-temperature ionic liquids (RTILs. Up until now, carbon-based SPEs have shown inferior behaviour compared to platinum and gold SPEs for gas sensing with RTIL solvents. The electrochemical reduction of oxygen (O2 in a range of RTILs has therefore been explored on home-made SPGEs, and is compared to the behaviour on commercially-available carbon SPEs (C-SPEs. Six common RTILs are initially employed for O2 detection using cyclic voltammetry (CV, and two RTILs ([C2mim][NTf2] and [C4mim][PF6] chosen for further detailed analytical studies. Long-term chronoamperometry (LTCA was also performed to test the ability of the sensor surface for real-time gas monitoring. Both CV and LTCA gave linear calibration graphs—for CV in the 10–100% vol. range, and for LTCA in the 0.1–20% vol. range—on the SPGE. The responses on the SPGE were far superior to the commercial C-SPEs; more instability in the electrochemical responses were observed on the C-SPEs, together with some breaking-up or dissolution of the electrode surface materials. This study highlights that not all screen-printed ink formulations are compatible with RTIL solvents for longer-term electrochemical experiments, and that the choice of RTIL is also important. Overall, the low-cost SPGEs appear to be promising platforms for the detection of O2, particularly in [C4mim][PF6].

  8. Electronic Structure of the Bismuth Family of High Temperature Superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Dunn, Lisa

    2002-03-07

    High temperature superconductivity remains the central intellectual problem in condensed matter physics fifteen years after its discovery. Angle resolved photoemission spectroscopy (ARPES) directly probes the electronic structure, and has played an important role in the field of high temperature superconductors. With the recent advances in sample growth and the photoemission technique, we are able to study the electronic structure in great detail, and address regimes that were previously inaccessible. This thesis work contains systematic photoemission studies of the electronic structure of the Bi-family of high temperature superconductors, which include the single-layer system (Bi2201), the bi-layer system (Bi2212), and the tri-layer system (Bi2223). We show that, unlike conventional BCS superconductors, phase coherence information emerges in the single particle excitation spectrum of high temperature superconductors as the superconducting peak in Bi2212. The universality and various properties of this superconducting peak are studied in various systems. We argue that the origin of the superconducting peak may provide the key to understanding the mechanism of High-Tc superconductors. In addition, we identified a new experimental energy scale in the bilayer material, the anisotropic intra-bilayer coupling energy. For a long time, it was predicted that this energy scale would cause bilayer band splitting. We observe this phenomenon, for the first time, in heavily overdoped Bi2212. This new observation requires the revision of the previous picture of the electronic excitation in the Brillouin zone boundary. As the first ARPES study of a trilayer system, various detailed electronic proper- ties of Bi2223 are examined. We show that, comparing with Bi2212, both superconducting gap and relative superconducting peak intensity become larger in Bi2223, however, the strength of the interlayer coupling within each unit cell is possibly weaker. These results suggest that the

  9. Electron temperature anisotropy constraints in the solar wind

    Czech Academy of Sciences Publication Activity Database

    Štverák, Štěpán; Trávníček, Pavel M.; Maksimovic, M.; Marsch, E.; Fazakerley, A.; Scime, E. E.

    2008-01-01

    Roč. 113, A3 /2008/ (2008), A03103/1-A03103/10 ISSN 0148-0227 R&D Projects: GA AV ČR IAA300420602 Grant - others:EU(XE) ESA-PECS project No. 98024 Institutional research plan: CEZ:AV0Z10030501; CEZ:AV0Z30420517 Keywords : solar wind electrons * temperature anisotropy * radial Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 3.147, year: 2008

  10. Electron Temperatures in W51 Complex from High Resolution, Low ...

    Indian Academy of Sciences (India)

    2001-03-09

    Mar 9, 2001 ... kinematics and local thermodynamic equilibrium (LTE) electron temperature (Te) of this region. H109α RRL observations by Wilsonet al.(1970) with a resolution of 4 and by Pankonin et al. (1979) with a resolution of 2.6 show that Te ∼ 6000 K in G49.5-0.4. Lower frequency observations for H137β and ...

  11. Deriving the coronal hole electron temperature: electron density dependent ionization / recombination considerations

    International Nuclear Information System (INIS)

    Doyle, John Gerard; Perez-Suarez, David; Singh, Avninda; Chapman, Steven; Bryans, Paul; Summers, Hugh; Savin, Daniel Wolf

    2010-01-01

    Comparison of appropriate theoretically derived line ratios with observational data can yield estimates of a plasma's physical parameters, such as electron density or temperature. The usual practice in the calculation of the line ratio is the assumption of excitation by electrons/protons followed by radiative decay. Furthermore, it is normal to use the so-called coronal approximation, i.e. one only considers ionization and recombination to and from the ground-state. A more accurate treatment is to include ionization/recombination to and from metastable levels. Here, we apply this to two lines from adjacent ionization stages, Mg IX 368 A and Mg X 625 A, which has been shown to be a very useful temperature diagnostic. At densities typical of coronal hole conditions, the difference between the electron temperature derived assuming the zero density limit compared with the electron density dependent ionization/recombination is small. This, however, is not the case for flares where the electron density is orders of magnitude larger. The derived temperature for the coronal hole at solar maximum is around 1.04 MK compared to just below 0.82 MK at solar minimum.

  12. Active silicon x-ray for measuring electron temperature

    International Nuclear Information System (INIS)

    Snider, R.T.

    1994-07-01

    Silicon diodes are commonly used for x-ray measurements in the soft x-ray region between a few hundred ev and 20 keV. Recent work by Cho has shown that the charge collecting region in an underbiased silicon detector is the depletion depth plus some contribution from a region near the depleted region due to charge-diffusion. The depletion depth can be fully characterized as a function of the applied bias voltage and is roughly proportional to the squart root of the bias voltage. We propose a technique to exploit this effect to use the silicon within the detector as an actively controlled x-ray filter. With reasonable silicon manufacturing methods, a silicon diode detector can be constructed in which the sensitivity of the collected charge to the impinging photon energy spectrum can be changed dynamically in the visible to above the 20 keV range. This type of detector could be used to measure the electron temperature in, for example, a tokamak plasma by sweeping the applied bias voltage during a plasma discharge. The detector samples different parts of the energy spectrum during the bias sweep, and the data collected contains enough information to determine the electron temperature. Benefits and limitations of this technique will be discussed along with comparisons to similar methods for measuring electron temperature and other applications of an active silicon x-ray filter

  13. 12th International Workshop on Low Temperature Electronics

    International Nuclear Information System (INIS)

    2017-01-01

    The present volume of the Journal of Physics: Conference Series represents contributions from participants of the 12th International Workshop on Low Temperature Electronics held in Tempe, Arizona, USA from September 18-21, 2016. The conference was organized by the School of Earth and Space Exploration at Arizona State University.The International Workshop on Low Temperature Electronics (WOLTE) is a biennial conference devoted to the presentation and exchange of the most recent advances in the field of low temperature electronics and its applications. This international forum is open to everyone in the field.The technical program included oral presentations and posters on fundamental properties of cryogenic materials, cryogenic transistors, quantum devices and systems, astronomy and physics instrumentation, and fabrication of cryogenic devices. More than 50 scientists and engineers from various academic, government, and industrial institutions in Europe, Asia, and the Americas attended the conference.We would like to thank all speakers for their presentations and all attendees for their participation. We would also like to express our sincerest gratitude to our sponsors: Lake Shore Cryotronics, ASU NewSpace, ASU School of Earth and Space Exploration, and IRA A. Fulton Schools of Engineering for making this conference possible. (paper)

  14. Validating the technological feasibility of yttria-stabilized zirconia-based semiconducting-ionic composite in intermediate-temperature solid oxide fuel cells

    Science.gov (United States)

    Cai, Yixiao; Wang, Baoyuan; Wang, Yi; Xia, Chen; Qiao, Jinli; van Aken, Peter A.; Zhu, Bin; Lund, Peter

    2018-04-01

    YSZ as the electrolyte of choice has dominated the progressive development of solid oxide fuel cell (SOFC) technologies for many years. To enable SOFCs operating at intermediate temperatures of 600 °C or below, major technical advances were built on a foundation of a thin-film YSZ electrolyte, NiO anode, and perovskite cathode, e.g. La0.6Sr0.4Co0.8Fe0.2O3-δ (LSCF). Inspired by functionalities in engineered heterostructure interfaces, the present work uses the components from state-of-the-art SOFCs, i.e, the anode NiO-YSZ and the cathode LSCF-YSZ, or the convergence of all three components, i.e., NiO-YSZ-LSCF, to fabricate semiconductor-ionic membranes (SIMs) and devices. A series of proof-of-concept fuel cell devices are designed by using each of the above SIMs sandwiched between two semiconducting Ni0.8Co0.15Al0.05LiO2-δ (NCAL) layers. We systematically compare these novel designs at 600 °C with two reference fuel cells: a commercial product of anode-supported YSZ electrolyte thin-film cell, and a lab-assembled fuel cell with a conventional configuration of NiO-YSZ (anode)/YSZ (electrolyte)/LSCF-YSZ (cathode). In comparison to the reference cells, the SIM device in a configuration of NCAL/NiO-YSZ-LSCF/NCAL reaches more than 3-fold enhancement of the maximum power output. By using spherical aberration-corrected transmission electron microscopy and spectroscopy approaches, this work offers insight into the mechanisms underlying SIM-associated SOFC performance enhancement.

  15. Temperature dependences in electron-stimulated desorption of neutral europium

    CERN Document Server

    Ageev, V N; Madey, T E

    2003-01-01

    The electron-stimulated desorption (ESD) yield for neutral europium (Eu) atoms from Eu layers adsorbed on oxygen-covered tungsten surfaces has been measured as a function of electron energy, europium coverage and degree of oxidation of tungsten, with an emphasis on effects of substrate temperature. The measurements have been carried out using a time-of-flight method and surface ionization detector. We expand on an earlier report, and compare ESD of multivalent Eu with ESD of monovalent alkali atoms, studied previously. The Eu atom ESD is a complicated function of Eu coverage, electron energy and substrate temperature. In the coverage range 0.05-0.35 monolayer (ML), overlapping resonant-like Eu atom yield peaks are observed at electron energies E sub e of 36 and 41 eV that might be associated with Eu or W shallow core level excitations. Additional resonant-like peaks are seen at E sub e of 54 and 84 eV that are associated with W 5p and 5s level excitations. The Eu atom yield peaks at 36 and 41 eV are seen only...

  16. Dispersion and Solvation Effects on the Structure and Dynamics of N719 Adsorbed to Anatase Titania (101) Surfaces in Room-Temperature Ionic Liquids: An ab Initio Molecular Simulation Study

    KAUST Repository

    Byrne, Aaron; English, Niall J.; Schwingenschlö gl, Udo; Coker, David F.

    2015-01-01

    Ab initio, density functional theory (DFT)-based molecular dynamics (MD) has been carried out to investigate the effect of explicit solvation on the dynamical and structural properties of a [bmim][NTf2] room-temperature ionic liquid (RTIL

  17. Potentialities in electronics of new high critical temperature superconductors

    International Nuclear Information System (INIS)

    Hartemann, P.

    1989-01-01

    The main electronic applications of superconductors involve the signal processing, the electromagnetic wave detection and the magnetometry. Characteristics of devices based on conventional superconductors cooled by liquid helium are given and the changes induced by incorporating high-temperature superconductors are estimated. After a survey of new superconductor properties, the superconducting devices for analog or digital signal processing are reviewed. The gains predicted for high-temperature superconducting analog devices are considered in greater detail. Different sections deal with the infrared or (sub)millimeter wave detection. The most sensitive apparatuses for magnetic measurements are based on SQUIDs. Features of SQUIDs made of granular high-temperature superconducting material samples (grain boundaries behave as barriers of intrinsic junctions) are discussed [fr

  18. Temperature profiles on the gadolinium surface during electron beam evaporation

    Energy Technology Data Exchange (ETDEWEB)

    Ohba, Hironori; Shibata, Takemasa [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1995-03-01

    The distributions of surface temperature of gadolinium in a water-cooled copper crucible during electron beam evaporation were measured by optical pyrometry. The surface temperatures were obtained from the radiation intensity ratio of the evaporating surface and a reference light source using Planck`s law of radiation. The emitted radiation from the evaporating surface and a reference source was detected by a CCD sensor through a band pass filter of 650 nm. The measured surface temperature generally agreed with those estimated from the deposition rate and the data of the saturated vapor pressure. At high input powers, it was found that the measured value had small difference with the estimated one due to variation of the surface condition. (author).

  19. Temperature profiles on the gadolinium surface during electron beam evaporation

    International Nuclear Information System (INIS)

    Ohba, Hironori; Shibata, Takemasa

    1995-01-01

    The distributions of surface temperature of gadolinium in a water-cooled copper crucible during electron beam evaporation were measured by optical pyrometry. The surface temperatures were obtained from the radiation intensity ratio of the evaporating surface and a reference light source using Planck's law of radiation. The emitted radiation from the evaporating surface and a reference source was detected by a CCD sensor through a band pass filter of 650 nm. The measured surface temperature generally agreed with those estimated from the deposition rate and the data of the saturated vapor pressure. At high input powers, it was found that the measured value had small difference with the estimated one due to variation of the surface condition. (author)

  20. Determination of gas temperature in the plasmatron channel according to the known distribution of electronic temperature

    Directory of Open Access Journals (Sweden)

    Gerasimov Alexander V.

    2013-01-01

    Full Text Available An analytical method to calculate the temperature distribution of heavy particles in the channel of the plasma torch on the known distribution of the electronic temperature has been proposed. The results can be useful for a number of model calculations in determining the most effective conditions of gas blowing through the plasma torch with the purpose of heating the heavy component. This approach allows us to understand full details about the heating of cold gas, inpouring the plasma, and to estimate correctly the distribution of the gas temperature inside the channel.

  1. Structures of self-assembled amphiphilic peptide-heterodimers: effects of concentration, pH, temperature and ionic strength

    KAUST Repository

    Luo, Zhongli

    2010-01-01

    The amphiphilic double-tail peptides AXG were studied regarding secondary structure and self-assembly in aqueous solution. The two tails A = Ala 6 and G = Gly6 are connected by a central pair X of hydrophilic residues, X being two aspartic acids in ADG, two lysines in AKG and two arginines in ARG. The peptide AD (Ala6Asp) served as a single-tail reference. The secondary structure of the four peptides was characterized by circular dichroism spectroscopy under a wide range of peptide concentrations (0.01-0.8 mM), temperatures (20-98 °C), pHs (4-9.5) and ionic strengths. In salt-free water both ADG and AD form a β-sheet type of structure at high concentration, low pH and low temperature, in a peptide-peptide driven assembly of individual peptides. The transition has a two-state character for ADG but not for AD, which indicates that the added tail in ADG makes the assembly more cooperative. By comparison the secondary structures of AKG and ARG are comparatively stable over the large range of conditions covered. According to dynamic light scattering the two-tail peptides form supra-molecular aggregates in water, but high-resolution AFM-imaging indicate that ordered (self-assembled) structures are only formed when salt (0.1 M NaCl) is added. Since the CD-studies indicate that the NaCl has only a minor effect on the peptide secondary structure we propose that the main role of the added salt is to screen the electrostatic repulsion between the peptide building blocks. According to the AFM images ADG and AKG support a correlation between nanofibers and a β-sheet or unordered secondary structure, whereas ARG forms fibers in spite of lacking β-sheet structure. Since the AKG and ARG double-tail peptides self-assemble into distinct nanostructures while their secondary structures are resistant to environment factors, these new peptides show potential as robust building blocks for nano-materials in various medical and nanobiotechnical applications. © 2010 The Royal Society

  2. Improvement of the stability of TiSnSb anode under lithiation using SEI forming additives and room temperature ionic liquid/DMC mixed electrolyte

    International Nuclear Information System (INIS)

    Zhang, W.; Ghamouss, F.; Mery, A.; Lemordant, D.; Dedryvère, R.; Monconduit, L.; Martinez, H.

    2015-01-01

    Highlights: • Lithiation and delithiation of TiSnSb conversion anode material • Room temperature ionic liquid based electrolyte • Fluoroethylene carbonate SEI builder additives • XPS and electrochemical analysis of the anode/electrolyte interface -- Abstract: The electrochemical behavior and the stability under cycling of TiSnSb anode for Li-ion batteries were investigated in room temperature ionic liquids based electrolyte. X-ray photoelectron spectroscopy (XPS), cyclic voltammetry, and electrochemical impedance (EIS) measurements have been performed to study the formation of surface film on the TiSnSb anode. Surface analysis was performed by a combined XPS core peaks and quantification data analysis, to establish the main components of the solid electrolyte interphase film (SEI). The key observation is that the thickness and the chemical nature of the SEI layer is strongly related to the electrolyte formulation and the addition of SEI layer forming additives. Vinylene carbonate (VC) and fluoroethylene carbonate (FEC) were applied in order to improve the anode/electrolyte interface. From XPS, EIS results and galvanostatic cycling the role of additives and ionic liquids as an effective stability improver has been highlighted

  3. To the problem of electron temperature control in plasma

    International Nuclear Information System (INIS)

    Galechyan, G.A.; Anna, P.R.

    1995-01-01

    One of the main problems in low temperature plasma is control plasma parameters at fixed values of current and gas pressure in the discharge. It is known that an increase in the intensity of sound wave directed along the positive column to values in excess of a definite threshold leads to essential rise of the temperature of electrons. However, no less important is the reduction of electron temperature in the discharge down to the value less than that in plasma in the absence external influence. It is known that to reduce the electron temperature in the plasma of CO 2 laser, easily ionizable admixture are usually introduced in the discharge area with the view of increasing the overpopulation. In the present work we shall show that the value of electron temperature can be reduced by varying of sound wave intensity at its lower values. The experiment was performed on an experimental setup consisted of the tube with length 52 cm and diameter 9.8 cm, two electrodes placed at the distance of 27 cm from each other. An electrodynamical radiator of sound wave was fastened to one of tube ends. Fastened to the flange at the opposite end was a microphone for the control of sound wave parameters. The studies were performed in range of pressures from 40 to 180 Torr and discharge currents from 40 to 110 mA. The intensity of sound wave was varied from 74 to 92 dB. The measurement made at the first resonance frequency f = 150 Hz of sound in the discharge tube, at which a quarter of wave length keep within the length of the tube. The measurement of longitudinal electric field voltage in plasma of positive column was conducted with the help of two probes according to the compensation method. Besides, the measurement of gas temperature in the discharge were taken. Two thermocouple sensors were arranged at the distance of 8 cm from the anode, one of them being installed on the discharge tube axis, the second-fixed the tube wall

  4. To the problem of electron temperature control in plasma

    Energy Technology Data Exchange (ETDEWEB)

    Galechyan, G.A. [Institute of Applied Problem of Physics, Yerevan (Armenia); Anna, P.R. [Raritan Valley Community College, Somerville, NJ (United States)

    1995-12-31

    One of the main problems in low temperature plasma is control plasma parameters at fixed values of current and gas pressure in the discharge. It is known that an increase in the intensity of sound wave directed along the positive column to values in excess of a definite threshold leads to essential rise of the temperature of electrons. However, no less important is the reduction of electron temperature in the discharge down to the value less than that in plasma in the absence external influence. It is known that to reduce the electron temperature in the plasma of CO{sub 2} laser, easily ionizable admixture are usually introduced in the discharge area with the view of increasing the overpopulation. In the present work we shall show that the value of electron temperature can be reduced by varying of sound wave intensity at its lower values. The experiment was performed on an experimental setup consisted of the tube with length 52 cm and diameter 9.8 cm, two electrodes placed at the distance of 27 cm from each other. An electrodynamical radiator of sound wave was fastened to one of tube ends. Fastened to the flange at the opposite end was a microphone for the control of sound wave parameters. The studies were performed in range of pressures from 40 to 180 Torr and discharge currents from 40 to 110 mA. The intensity of sound wave was varied from 74 to 92 dB. The measurement made at the first resonance frequency f = 150 Hz of sound in the discharge tube, at which a quarter of wave length keep within the length of the tube. The measurement of longitudinal electric field voltage in plasma of positive column was conducted with the help of two probes according to the compensation method. Besides, the measurement of gas temperature in the discharge were taken. Two thermocouple sensors were arranged at the distance of 8 cm from the anode, one of them being installed on the discharge tube axis, the second-fixed the tube wall.

  5. Packaging Technologies for High Temperature Electronics and Sensors

    Science.gov (United States)

    Chen, Liangyu; Hunter, Gary W.; Neudeck, Philip G.; Beheim, Glenn M.; Spry, David J.; Meredith, Roger D.

    2013-01-01

    This paper reviews ceramic substrates and thick-film metallization based packaging technologies in development for 500degC silicon carbide (SiC) electronics and sensors. Prototype high temperature ceramic chip-level packages and printed circuit boards (PCBs) based on ceramic substrates of aluminum oxide (Al2O3) and aluminum nitride (AlN) have been designed and fabricated. These ceramic substrate-based chiplevel packages with gold (Au) thick-film metallization have been electrically characterized at temperatures up to 550degC. A 96% alumina based edge connector for a PCB level subsystem interconnection has also been demonstrated recently. The 96% alumina packaging system composed of chip-level packages and PCBs has been tested with high temperature SiC devices at 500degC for over 10,000 hours. In addition to tests in a laboratory environment, a SiC JFET with a packaging system composed of a 96% alumina chip-level package and an alumina printed circuit board mounted on a data acquisition circuit board was launched as a part of the MISSE-7 suite to the International Space Station via a Shuttle mission. This packaged SiC transistor was successfully tested in orbit for eighteen months. A spark-plug type sensor package designed for high temperature SiC capacitive pressure sensors was developed. This sensor package combines the high temperature interconnection system with a commercial high temperature high pressure stainless steel seal gland (electrical feed-through). Test results of a packaged high temperature capacitive pressure sensor at 500degC are also discussed. In addition to the pressure sensor package, efforts for packaging high temperature SiC diode-based gas chemical sensors are in process.

  6. In situ direct observation of photocorrosion in ZnO crystals in ionic liquid using a laser-equipped high-voltage electron microscope

    Directory of Open Access Journals (Sweden)

    J. Ishioka

    2017-03-01

    Full Text Available ZnO photocatalysts in water react with environmental water molecules and corrode under illumination. ZnO nanorods in water can also grow because of water splitting induced by UV irradiation. To investigate their morphological behavior caused by crystal growth and corrosion, here we developed a new laser-equipped high-voltage electron microscope and observed crystal ZnO nanorods immersed in ionic liquid. Exposing the specimen holder to a laser with a wavelength of 325 nm, we observed the photocorrosion in situ at the atomic scale for the first time. This experiment revealed that Zn and O atoms near the interface between the ZnO nanorods and the ionic liquid tended to dissolve into the liquid. The polarity and facet of the nanorods were strongly related to photocorrosion and crystal growth.

  7. Solvated electrons at elevated temperatures in different alcohols: Temperature and molecular structure effects

    Energy Technology Data Exchange (ETDEWEB)

    Yan, Yu [Department of Nuclear Engineering and Management, Graduate School of Engineering, University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-8656 (Japan); Lin, Mingzhang [Nuclear Science and Engineering Directorate, Japan Atomic Energy Agency, 2-4 Shirakata-Shirane, Tokai, Naka, Ibaraki 319-1195 (Japan); Katsumura, Yosuke, E-mail: katsu@n.t.u-tokyo.ac.j [Department of Nuclear Engineering and Management, Graduate School of Engineering, University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-8656 (Japan); Nuclear Professional School, Graduate School of Engineering, University of Tokyo, 2-22 Shirakata-Shirane, Tokai, Naka, Ibaraki 319-1188 (Japan); Fu, Haiying; Muroya, Yusa [Nuclear Professional School, Graduate School of Engineering, University of Tokyo, 2-22 Shirakata-Shirane, Tokai, Naka, Ibaraki 319-1188 (Japan)

    2010-12-15

    The absorption spectra of solvated electrons in pentanol, hexanol and octanol are measured from 22 to 200, 22 to 175 and 50 to150 {sup o}C, respectively, at a fixed pressure of 15 MPa, using nanosecond pulse radiolysis technique. The results show that the peak positions of the absorption spectra have a red-shift (shift to longer wavelengths) as temperature increases, similar to water and other alcohols. Including the above mentioned data, a compilation of currently available experimental data on the energy of absorption maximum (E{sub max}) of solvated electrons changed with temperature in monohydric alcohols, diols and triol is presented. E{sub max} of solvated electron is larger in those alcohols that have more OH groups at all the temperatures. The molecular structure effect, including OH numbers, OH position and carbon chain length, is investigated. For the primary alcohols with same OH group number and position, the temperature coefficient increases with increase in chain length. For the alcohols with same chain length and OH numbers, temperature coefficient is larger for the symmetric alcohols than the asymmetric ones.

  8. High-temperature synthesis of highly hydrothermal stable mesoporous silica and Fe-SiO2 using ionic liquid as a template

    International Nuclear Information System (INIS)

    Liu, Hong; Wang, Mengyang; Hu, Hongjiu; Liang, Yuguang; Wang, Yong; Cao, Weiran; Wang, Xiaohong

    2011-01-01

    Mesoporous silicas and Fe-SiO 2 with worm-like structures have been synthesized using a room temperature ionic liquid, 1-hexadecane-3-methylimidazolium bromide, as a template at a high aging temperature (150-190 o C) with the assistance of NaF. The hydrothermal stability of mesoporous silica was effectively improved by increasing the aging temperature and adding NaF to the synthesis gel. High hydrothermally stable mesoporous silica was obtained after being aged at 190 o C in the presence of NaF, which endured the hydrothermal treatment in boiling water at least for 10 d or steam treatment at 600 o C for 6 h. The ultra hydrothermal stability could be attributed to its high degree of polymerization of silicate. Furthermore, highly hydrothermal stable mesoporous Fe-SiO 2 has been synthesized, which still remained its mesostructure after being hydrothermally treated at 100 o C for 12 d or steam-treated at 600 o C for 6 h. -- Graphical abstract: Worm-like mesoporous silica and Fe-SiO 2 with high hydrothermal stability have been synthesized using ionic liquid 1-hexadecane-3-methylimidazolium bromide as a template under the assistance of NaF at high temperature. Display Omitted Research highlights: → Increasing aging temperature improved the hydrothermal stability of materials. →Addition of NaF enhanced the polymerization degree of silicates. → Mesoporous SiO 2 and Fe-SiO 2 obtained have remarkable hydrothermal stability.

  9. Temperature dependence of the electronic structure of semiconductors and insulators

    Energy Technology Data Exchange (ETDEWEB)

    Poncé, S., E-mail: samuel.pon@gmail.com; Gillet, Y.; Laflamme Janssen, J.; Gonze, X. [European Theoretical Spectroscopy Facility and Institute of Condensed Matter and Nanosciences, Université catholique de Louvain, Chemin des étoiles 8, bte L07.03.01, B-1348 Louvain-la-neuve (Belgium); Marini, A. [Consiglio Nazionale delle Ricerche (CNR), Via Salaria Km 29.3, CP 10, 00016 Monterotondo Stazione (Italy); Verstraete, M. [European Theoretical Spectroscopy Facility and Physique des matériaux et nanostructures, Université de Liège, Allée du 6 Août 17, B-4000 Liège (Belgium)

    2015-09-14

    The renormalization of electronic eigenenergies due to electron-phonon coupling (temperature dependence and zero-point motion effect) is sizable in many materials with light atoms. This effect, often neglected in ab initio calculations, can be computed using the perturbation-based Allen-Heine-Cardona theory in the adiabatic or non-adiabatic harmonic approximation. After a short description of the recent progresses in this field and a brief overview of the theory, we focus on the issue of phonon wavevector sampling convergence, until now poorly understood. Indeed, the renormalization is obtained numerically through a slowly converging q-point integration. For non-zero Born effective charges, we show that a divergence appears in the electron-phonon matrix elements at q → Γ, leading to a divergence of the adiabatic renormalization at band extrema. This problem is exacerbated by the slow convergence of Born effective charges with electronic wavevector sampling, which leaves residual Born effective charges in ab initio calculations on materials that are physically devoid of such charges. Here, we propose a solution that improves this convergence. However, for materials where Born effective charges are physically non-zero, the divergence of the renormalization indicates a breakdown of the adiabatic harmonic approximation, which we assess here by switching to the non-adiabatic harmonic approximation. Also, we study the convergence behavior of the renormalization and develop reliable extrapolation schemes to obtain the converged results. Finally, the adiabatic and non-adiabatic theories, with corrections for the slow Born effective charge convergence problem (and the associated divergence) are applied to the study of five semiconductors and insulators: α-AlN, β-AlN, BN, diamond, and silicon. For these five materials, we present the zero-point renormalization, temperature dependence, phonon-induced lifetime broadening, and the renormalized electronic band structure.

  10. Ionic structures and transport properties of hot dense W and U plasmas

    Science.gov (United States)

    Hou, Yong; Yuan, Jianmin

    2016-10-01

    We have combined the average-atom model with the hyper-netted chain approximation (AAHNC) to describe the electronic and ionic structure of uranium and tungsten in the hot dense matter regime. When the electronic structure is described within the average-atom model, the effects of others ions on the electronic structure are considered by the correlation functions. And the ionic structure is calculated though using the hyper-netted chain (HNC) approximation. The ion-ion pair potential is calculated using the modified Gordon-Kim model based on the electronic density distribution in the temperature-depended density functional theory. And electronic and ionic structures are determined self-consistently. On the basis of the ion-ion pair potential, we perform the classical (CMD) and Langevin (LMD) molecular dynamics to simulate the ionic transport properties, such as ionic self-diffusion and shear viscosity coefficients, through the ionic velocity correlation functions. Due that the free electrons become more and more with increasing the plasma temperature, the influence of the electron-ion collisions on the transport properties become more and more important.

  11. Electron Scattering Studies of Gas Phase Molecular Structure at High Temperature

    Science.gov (United States)

    Mawhorter, Richard J., Jr.

    A high precision counting electron diffraction study of the structure of gaseous sulfur dioxide as a function of temperature from 300(DEGREES) to 1000(DEGREES)K is presented. The results agree well with current theory, and yield insight into the effects of anharmonicity on molecular structure. Another aspect of molecular structure is the molecular charge density distribution. The difference (DELTA)(sigma) is between the electron scattering cross sections for the actual molecule and independent atom model (IAM) are a sensitive measure of the change in this distribution due to bond formation. These difference cross sections have been calculated using ab initio methods, and the results for a wide range of simple polyatomic molecules are presented. Such calculations are routinely done for a single, fixed molecular geometry, an approach which neglects the effects of the vibrational motion of real molecules. The effect of vibrational averaging is studied in detail for the three normal vibrational modes of H(,2)O in the ground state. The effects are small, lending credence to the practice of comparing cross sections calculated at a fixed geometry with inherently averaged experimental data. The efficacy of the standard formula used to account for vibrational averaging in the IAM is also examined. Finally, the nature of the ionic bond is probed with an experimental study of the structure of alkali chlorides, NaCl, KCl, RbCl, and CsCl, in the gas phase. Temperatures from 840-960(DEGREES)K were required to achieve the necessary vapor pressures of approximately 0.01 torr. A planar rhombic structure for the dimer molecule is confirmed, with a fairly uniform decrease of the chlorine-alkali-chlorine angle as the alkalis increase in size. The experiment also yields information on the amount of dimer present in the vapor, and these results are compared with thermodynamic values.

  12. Transmission electron microscopy for elucidating the impact of silver-based treatments (ionic silver versus nanosilver-containing coating) on the model yeast Saccharomyces cerevisiae

    Energy Technology Data Exchange (ETDEWEB)

    Despax, B; Saulou, C; Raynaud, P [Universite de Toulouse, UPS, INPT, LAPLACE, 118 route de Narbonne, F-31062 Toulouse cedex 9 (France); Datas, L [Universite de Toulouse, UPS, INPT, CIRIMAT, 118 route de Narbonne, F-31062 Toulouse cedex 9 (France); Mercier-Bonin, M [Universite de Toulouse, INSA, UPS, INP, LISBP, 135 Avenue de Rangueil, F-31077 Toulouse (France)

    2011-04-29

    After exposure to ionic silver or nanosilver-containing plasma coating, the same visual aspect of scanning transmission electron microscopy (STEM) images was observed for the model yeast Saccharomyces cerevisiae. The main common feature was the presence of electron-dense nodules all over the cell. However, high resolution TEM (HRTEM), STEM, energy dispersive x-ray microanalysis spectroscopy (EDS) and electron microdiffraction revealed some striking differences. Regarding ionic silver exposure, the formation of electron-dense nodules was related to the Ag{sup +} reactivity towards sulfur-containing compounds to form clusters with Ag{sub 2}S-like structures, together with the production of a few silver nanocrystals, mainly at the cell wall periphery. For nanosilver-based treatment, some sulfur-containing silver clusters preferentially located at the cell wall periphery were detected, together with nodules composed of silver, sulfur and phosphorus all over the cell. In both silver-based treatments, nitrogen and silver signals overlapped, confirming the affinity of silver entities for proteinaceous compounds. Moreover, in the case of nanosilver, interactions of silver with phosphorus-containing subcellular structures were indicated.

  13. Preparation and characterization of room temperature ionic liquid/single-walled carbon nanotube nanocomposites and their application to the direct electrochemistry of heme-containing proteins/enzymes

    International Nuclear Information System (INIS)

    Du, Pan; Liu, Shuna; Wu, Ping; Cai, Chenxin

    2007-01-01

    This work describes the formation and possible electrochemical application of a novel nanocomposite based on single-walled carbon nanotubes (SWNTs) and imidazolium-based room-temperature ionic liquids (RTILs) of 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim]BF 4 , a hydrophilic RTIL) and 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim]PF 6 , a hydrophobic RTIL). The nanocomposites ([bmim]BF 4 -SWNTs, and [bmim]PF 6 -SWNTs) were formed by simply grinding the SWNTs with the respective RTIL. The results of the X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy indicated that the nanocomposites were formed by adsorption of an imidazolium ion on the surface of SWNTs via the 'cation-π' interaction. SEM images showed that [bmim]BF 4 -SWNTs (or [bmim]PF 6 -SWNTs) nanocomposites could uniformly cover the surface of a glassy carbon (GC) electrode resulting in a RTILs-SWNTs/GC modified electrode with a high stability. The RTILs-SWNTs composite could be readily used as a matrix to immobilize heme-containing proteins/enzymes (myoglobin, cytochrome c, and horseradish peroxidase) without undergoing denaturation, as was verified by UV-vis and circular dichroic (CD) spectroscopic results. The voltammetric results showed that heme-containing proteins/enzymes entrapped in RTILs-SWNTs composites displayed a pair of well-defined, stable redox peaks, which were ascribed to their direct electron-transfer reactions. The results of controlled experiments showed that the positive charged imidazolium ion played a significant effect on the electrochemical parameters, such as the redox peak separation and the value of the formal potentials, etc., of the electron-transfer reaction of non-neutral species dissolved in solution or immobilized on the electrode surface. Further results demonstrated that the heme-containing proteins/enzymes entrapped in RTILs-SWNTs composites could still retain their bioelectrocatalytic activity toward the reduction of oxygen and hydrogen

  14. Regulation of electron temperature gradient turbulence by zonal flows driven by trapped electron modes

    Science.gov (United States)

    Asahi, Y.; Ishizawa, A.; Watanabe, T.-H.; Tsutsui, H.; Tsuji-Iio, S.

    2014-05-01

    Turbulent transport caused by electron temperature gradient (ETG) modes was investigated by means of gyrokinetic simulations. It was found that the ETG turbulence can be regulated by meso-scale zonal flows driven by trapped electron modes (TEMs), which are excited with much smaller growth rates than those of ETG modes. The zonal flows of which radial wavelengths are in between the ion and the electron banana widths are not shielded by trapped ions nor electrons, and hence they are effectively driven by the TEMs. It was also shown that an E × B shearing rate of the TEM-driven zonal flows is larger than or comparable to the growth rates of long-wavelength ETG modes and TEMs, which make a main contribution to the turbulent transport before excitation of the zonal flows.

  15. Density, viscosity, and surface tension of synthesis grade imidazolium,pyridinium, and pyrrolidinium based room temperature ionic liquids

    NARCIS (Netherlands)

    Galan Sanchez, L.M.; Espel, J.R.; Onink, S.A.F.; Meindersma, G.W.; Haan, de A.B.

    2009-01-01

    Density, viscosity, and surface tension data sets of 13 ionic liquids formed by imidazolium, pyridinium, or pyrrolidinium cations paired with dicyanamide (DCA), tetrafluoroborate (BF4¯), thiocyanate (SCN¯),methylsulfate (MeSO4¯), and trifluoroacetate (TFA) anions are reported. The properties were

  16. Soy Glycenin: Influence of pH and Ionic Strength on Solubility and Molecular Structure at Ambient Temperatures

    NARCIS (Netherlands)

    Lakemond, C.M.M.; Jongh, de H.H.J.; Hessing, M.; Gruppen, H.; Voragen, A.G.J.

    2000-01-01

    This study describes the relationship between the solubility of glycinin, a major soy protein, and its structural properties at a quaternary, tertiary, and secondary folding level under conditions representative for food products. When the ionic strength is lowered from 0.5 to 0.2 or 0.03, the basic

  17. Electron temperature gradient driven instability in the tokamak boundary plasma

    International Nuclear Information System (INIS)

    Xu, X.Q.; Rosenbluth, M.N.; Diamond, P.H.

    1992-01-01

    A general method is developed for calculating boundary plasma fluctuations across a magnetic separatrix in a tokamak with a divertor or a limiter. The slab model, which assumes a periodic plasma in the edge reaching the divertor or limiter plate in the scrape-off layer(SOL), should provide a good estimate, if the radial extent of the fluctuation quantities across the separatrix to the edge is small compared to that given by finite particle banana orbit. The Laplace transform is used for solving the initial value problem. The electron temperature gradient(ETG) driven instability is found to grow like t -1/2 e γmt

  18. Electron cyclotron emission measurements on JET: Michelson interferometer, new absolute calibration, and determination of electron temperature.

    Science.gov (United States)

    Schmuck, S; Fessey, J; Gerbaud, T; Alper, B; Beurskens, M N A; de la Luna, E; Sirinelli, A; Zerbini, M

    2012-12-01

    At the fusion experiment JET, a Michelson interferometer is used to measure the spectrum of the electron cyclotron emission in the spectral range 70-500 GHz. The interferometer is absolutely calibrated using the hot/cold technique and, in consequence, the spatial profile of the plasma electron temperature is determined from the measurements. The current state of the interferometer hardware, the calibration setup, and the analysis technique for calibration and plasma operation are described. A new, full-system, absolute calibration employing continuous data acquisition has been performed recently and the calibration method and results are presented. The noise level in the measurement is very low and as a result the electron cyclotron emission spectrum and thus the spatial profile of the electron temperature are determined to within ±5% and in the most relevant region to within ±2%. The new calibration shows that the absolute response of the system has decreased by about 15% compared to that measured previously and possible reasons for this change are presented. Temperature profiles measured with the Michelson interferometer are compared with profiles measured independently using Thomson scattering diagnostics, which have also been recently refurbished and recalibrated, and agreement within experimental uncertainties is obtained.

  19. The effect of defect types on the electronic and optical properties of graphene nanoflakes physisorbed by ionic liquids.

    Science.gov (United States)

    Shakourian-Fard, Mehdi; Kamath, Ganesh

    2017-02-08

    Defect engineering and non-covalent interaction strategies allow for dramatically tuning the optoelectronic properties of graphene. Using ab initio density functional theory (M06-2X/cc-pVDZ), we find that the nature of defects on the graphene nanoflakes (GNFs) and the size of defective GNF (DGNF) surfaces affect the binding energy (ΔE b ) of ionic liquids (ILs) and the UV-Vis absorption spectra of DGNFIL complexes. Further, our results indicate that increasing the size of DGNFs affects the geometrical structure of the surfaces and increases the binding energy of ILs by about 10%. Analysis based on AIM and EDA shows that the interactions between ILs and DGNFs are non-covalent in nature (dispersion energy being dominant) and associated with charge transfer between the IL and nanoflakes. A comparison between the ΔE b values of ILs on DGNFs, GNFs, and h-BN nanoflakes (h-BNNF) shows that the presence of defects on the GNF surfaces increases the binding energy values as follows: DGNFIL > pristine GNFIL > h-BNNFIL. Our calculations indicate that increasing the size of DGNF surfaces leads to a decrease in the HOMO-LUMO energy gap (E g ) of the DGNF surfaces. Orbital energy and density of state calculations show that the E g of DV(SW)-GNFs decreases upon IL adsorption and their Fermi energy level is shifted depending on the type of IL, thus enabling better conductivity. Reactivity descriptors generally indicate that the chemical potential (μ) and chemical hardness (η) of nanoflakes decrease upon IL adsorption, whereas the electrophilicity index (ω) increases. The UV-Vis absorption spectrum of DV-GNF and SW-GNF shows four bands in the visible spectrum which correspond to π → π* transitions with the absorption bands of SW-GNF appearing at higher wavelengths than those of DV-GNF. The most intense absorption bands in DV-GNF (λ = 348 nm) and SW-GNF (λ = 375 nm) are associated with electronic transitions HOMO-1 → LUMO+2 and HOMO → LUMO+1, respectively. In addition

  20. Synthesis of novel room temperature chiral ionic liquids: application as reaction media for the heck arylation of aza-endocyclic acrylates

    Energy Technology Data Exchange (ETDEWEB)

    Pastre, Julio C.; Correia, Carlos R.D., E-mail: genisson@chimie.ups-tlse.f, E-mail: roque@iqm.unicamp.b [Universidade Estadual de Campinas (UNICAMP), SP (Brazil). Inst. de Quimica; Genisson, Yves [Universite Paul Sabatier, Toulouse (France). Lab. de Synthese et Physicochimie des Molecules d' Interet Biologique; Saffon, Nathalie [Universite Paul Sabatier, Toulouse (France). Structure federative toulousaine en chimie moleculaire (SFTCM); Dandurand, Jany [Universite Paul Sabatier, Toulouse (France). Lab. de Physique des Polymeres

    2010-07-01

    New achiral and chiral RTILs were prepared using novel and/or optimized synthetic routes. These new series of imidazolinium, imidazolium, pyridinium and nicotine-derived ionic liquids were fully characterized including differential scanning calorimetry (DSC) analysis. The performance of these achiral and chiral room temperature ionic liquids (RTILs) was demonstrated by means of the Heck arylation of endocyclic acrylates employing arenediazonium salts and aryl iodides. The Heck arylations performed in the presence of these ionic entities, either as a solvent or as an additive, were effective leading to complete conversion of the substrate and good to excellent yield of the Heck adduct. In spite of the good performances, no asymmetric induction was observed in any of the cases studied. Two new diastereoisomeric NHC-palladium complexes were prepared in good yields from a chiral imidazolium salt and their structure characterized by X-ray diffraction. Overall, the Heck arylations employing arenediazonium tetrafluoroborates in RTILs were more effective than the traditional protocols employing aryl iodides in terms of reactivity and yields. (author)

  1. Experimental study of water absorption of electronic components and internal local temperature and humidity into electronic enclosure

    DEFF Research Database (Denmark)

    Conseil, Helene; Jellesen, Morten Stendahl; Ambat, Rajan

    2014-01-01

    Corrosion reliability of electronic products is a key factor for electronics industry, and today there is a large demand for performance reliability in large spans of temperature and humidity during day and night shifts. Corrosion failures are still seen due to the effects of temperature, humidity......, differential humidity, and temperature effects simulating day/night, and the use of desiccants....

  2. A physicochemical investigation of ionic liquid mixtures† †Electronic supplementary information (ESI) available. See DOI: 10.1039/c4sc02931c Click here for additional data file.

    Science.gov (United States)

    Clough, Matthew T.; Crick, Colin R.; Gräsvik, John; Niedermeyer, Heiko; Whitaker, Oliver P.

    2015-01-01

    Ionic liquids have earned the reputation of being ‘designer solvents’ due to the wide range of accessible properties and the degree of fine-tuning afforded by varying the constituent ions. Mixtures of ionic liquids offer the opportunity for further fine-tuning of properties. A broad selection of common ionic liquid cations and anions are employed to create a sample of binary and reciprocal binary ionic liquid mixtures, which are analysed and described in this paper. Physical properties such as the conductivity, viscosity, density and phase behaviour (glass transition temperatures) are examined. In addition, thermal stabilities of the mixtures are evaluated. The physical properties examined for these formulations are found to generally adhere remarkably closely to ideal mixing laws, with a few consistent exceptions, allowing for the facile prediction and control of properties of ionic liquid mixtures. PMID:29560198

  3. Thermodynamic aspects of the electron transfer across the interface between water and a hydrophobic redox-active ionic liquid

    Czech Academy of Sciences Publication Activity Database

    Langmaier, Jan; Samec, Zdeněk

    2011-01-01

    Roč. 58, - (2011), s. 606-613 ISSN 0013-4686 R&D Projects: GA ČR GAP206/11/0707; GA ČR GAP206/10/1231 Institutional research plan: CEZ:AV0Z40400503 Keywords : redox-active ionic liquid * membrane * cyclic voltammetry Subject RIV: CG - Electrochemistry Impact factor: 3.832, year: 2011

  4. Ionic Liquids in Tribology

    Directory of Open Access Journals (Sweden)

    Ichiro Minami

    2009-06-01

    Full Text Available Current research on room-temperature ionic liquids as lubricants is described. Ionic liquids possess excellent properties such as non-volatility, non-flammability, and thermo-oxidative stability. The potential use of ionic liquids as lubricants was first proposed in 2001 and approximately 70 articles pertaining to fundamental research on ionic liquids have been published through May 2009. A large majority of the cations examined in this area are derived from 1,3-dialkylimidazolium, with a higher alkyl group on the imidazolium cation being beneficial for good lubrication, while it reduces the thermo-oxidative stability. Hydrophobic anions provide both good lubricity and significant thermo-oxidative stability. The anions decompose through a tribochemical reaction to generate metal fluoride on the rubbed surface. Additive technology to improve lubricity is also explained. An introduction to tribology as an interdisciplinary field of lubrication is also provided.

  5. Ionic liquids in tribology.

    Science.gov (United States)

    Minami, Ichiro

    2009-06-24

    Current research on room-temperature ionic liquids as lubricants is described. Ionic liquids possess excellent properties such as non-volatility, non-flammability, and thermo-oxidative stability. The potential use of ionic liquids as lubricants was first proposed in 2001 and approximately 70 articles pertaining to fundamental research on ionic liquids have been published through May 2009. A large majority of the cations examined in this area are derived from 1,3-dialkylimidazolium, with a higher alkyl group on the imidazolium cation being beneficial for good lubrication, while it reduces the thermo-oxidative stability. Hydrophobic anions provide both good lubricity and significant thermo-oxidative stability. The anions decompose through a tribochemical reaction to generate metal fluoride on the rubbed surface. Additive technology to improve lubricity is also explained. An introduction to tribology as an interdisciplinary field of lubrication is also provided.

  6. Room temperature ionic liquids enhanced the speciation of Cr(VI) and Cr(III) by hollow fiber liquid phase microextraction combined with flame atomic absorption spectrometry

    International Nuclear Information System (INIS)

    Zeng, Chujie; Lin, Yao; Zhou, Neng; Zheng, Jiaoting; Zhang, Wei

    2012-01-01

    Highlights: ► First reported enhancement effect of RTILs in HF-LPME for the speciation of chromium. ► The addition of RTILs led to 3.5 times improvement of the sensitivity of Cr(VI). ► The proposed method is a simplicity, sensitivity, low cost, green method. - Abstract: A new method for the speciation of Cr(VI) and Cr(III) based on enhancement effect of room temperature ionic liquids (RTILs) for hollow fiber liquid phase microextraction (HF-LPME) combined with flame atomic absorption spectrometry (FAAS) was developed. Room temperature ionic liquids (RTILs) and diethyldithiocarbamate (DDTC) were used enhancement reagents and chelating reagent, respectively. The addition of room temperature ionic liquids led to 3.5 times improvement in the determination of Cr(VI). In this method, Cr(VI) reacts with DDTC yielding a hydrophobic complex, which is subsequently extracted into the lumen of hollow fiber, whereas Cr(III) is remained in aqueous solutions. The extraction organic phase was injected into FAAS for the determination of Cr(VI). Total Cr concentration was determined after oxidizing Cr(III) to Cr(VI) in the presence of KMnO 4 and using the extraction procedure mentioned above. Cr(III) was calculated by subtracting of Cr(VI) from the total Cr. Under optimized conditions, a detection limit of 0.7 ng mL −1 and an enrichment factor of 175 were achieved. The relative standard deviation (RSD) was 4.9% for Cr(VI) (40 ng mL −1 , n = 5). The proposed method was successfully applied to the speciation of chromium in natural water samples with satisfactory results.

  7. Room temperature ionic liquids enhanced the speciation of Cr(VI) and Cr(III) by hollow fiber liquid phase microextraction combined with flame atomic absorption spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Zeng, Chujie, E-mail: cjzeng@126.com [Department of Chemistry and Material, Yulin Normal College, Yulin, Guangxi 537000 (China); Lin, Yao; Zhou, Neng; Zheng, Jiaoting; Zhang, Wei [Department of Chemistry and Material, Yulin Normal College, Yulin, Guangxi 537000 (China)

    2012-10-30

    Highlights: Black-Right-Pointing-Pointer First reported enhancement effect of RTILs in HF-LPME for the speciation of chromium. Black-Right-Pointing-Pointer The addition of RTILs led to 3.5 times improvement of the sensitivity of Cr(VI). Black-Right-Pointing-Pointer The proposed method is a simplicity, sensitivity, low cost, green method. - Abstract: A new method for the speciation of Cr(VI) and Cr(III) based on enhancement effect of room temperature ionic liquids (RTILs) for hollow fiber liquid phase microextraction (HF-LPME) combined with flame atomic absorption spectrometry (FAAS) was developed. Room temperature ionic liquids (RTILs) and diethyldithiocarbamate (DDTC) were used enhancement reagents and chelating reagent, respectively. The addition of room temperature ionic liquids led to 3.5 times improvement in the determination of Cr(VI). In this method, Cr(VI) reacts with DDTC yielding a hydrophobic complex, which is subsequently extracted into the lumen of hollow fiber, whereas Cr(III) is remained in aqueous solutions. The extraction organic phase was injected into FAAS for the determination of Cr(VI). Total Cr concentration was determined after oxidizing Cr(III) to Cr(VI) in the presence of KMnO{sub 4} and using the extraction procedure mentioned above. Cr(III) was calculated by subtracting of Cr(VI) from the total Cr. Under optimized conditions, a detection limit of 0.7 ng mL{sup -1} and an enrichment factor of 175 were achieved. The relative standard deviation (RSD) was 4.9% for Cr(VI) (40 ng mL{sup -1}, n = 5). The proposed method was successfully applied to the speciation of chromium in natural water samples with satisfactory results.

  8. Graphene-ionic liquid composites

    Energy Technology Data Exchange (ETDEWEB)

    Aksay, Ilhan A.; Korkut, Sibel; Pope, Michael; Punckt, Christian

    2016-11-01

    Method of making a graphene-ionic liquid composite. The composite can be used to make elec-trodes for energy storage devices, such as batteries and supercapacitors. Dis-closed and claimed herein is method of making a graphene-ionic liquid com-posite, comprising combining a graphene source with at least one ionic liquid and heating the combination at a temperature of at least about 130 .degree. C.

  9. Thermodynamic properties of deep eutectic solvent and ionic liquid mixtures at temperatures from 293.15 K to 343.15 K

    Science.gov (United States)

    Achsah, R. S.; Shyam, S.; Mayuri, N.; Anantharaj, R.

    2018-04-01

    Deep eutectic solvents (DES) and ionic liquids (ILs) have their applications in various fields of research and in industries due to their attractive physiochemical properties. In this study, the combined thermodynamic properties of DES (choline chloride-glycerol) + IL1 (1-butyl-3-methylimiazolium acetate) and DES(choline chloride-glycerol) + IL2 (1-ethyl-3-methylimadzolium ethyl sulphate) have been studied. The thermodynamic properties such as excess molar volume, partial molar volume, excess partial molar volume and apparent molar volume were calculated for different mole fractions ranging from 0 to 1 and varying temperatures from 293.15 K to 343.15 K. In order to know the solvent properties of DESs and ILs mixtures at different temperatures and their molecular interactions to enhance the solvent performance and process efficiency at fixed composition and temperature the thermodynamic properties were analyzed.

  10. Numerical simulation of transient moisture and temperature distribution in polycarbonate and aluminum electronic enclosures

    DEFF Research Database (Denmark)

    Shojaee Nasirabadi, Parizad; Jabbaribehnam, Mirmasoud; Hattel, Jesper Henri

    2016-01-01

    The challenge of developing a reliable electronic product requires huge amounts of resources and knowledge. Temperature and thermal features directly affect the life of electronic products. Furthermore, moisture can be damaging for electronic components. Nowadays, computational fluid dynamics (CF...

  11. Effective temperature of the non-equilibrium electrons in a degenerate semiconductor at low lattice temperature

    Energy Technology Data Exchange (ETDEWEB)

    Das, B.; Basu, A.; Das, J.; Bhattacharya, D.P., E-mail: d_p_bhattacharya@rediffmail.com

    2015-10-01

    The energy balance equation for the electron–phonon system is recast taking the degeneracy of the carrier ensemble into account. The effect of degeneracy on the field dependence of the temperature of the non-equilibrium carriers has been studied by solving the same equation. The high field distribution function of the carriers is assumed to be given by the Fermi Dirac function at the field dependent carrier temperature. The distribution function has been approximated in a way that facilitates analytical solution of the problem without any serious loss of accuracy. The field dependence of the electron temperature thus obtained seems to be significantly different from what follows had the degeneracy not been taken into account. The agreement of the results obtained from the present analysis with the available experimental data for Ge and InSb are quite satisfactory. The scope of further refinement of the present theory is highlighted.

  12. Learning Ionic

    CERN Document Server

    Ravulavaru, Arvind

    2015-01-01

    This book is intended for those who want to learn how to build hybrid mobile applications using Ionic. It is also ideal for people who want to explore theming for Ionic apps. Prior knowledge of AngularJS is essential to complete this book successfully.

  13. Sheath and heat flow of a two-electron-temperature plasma in the presence of electron emission

    International Nuclear Information System (INIS)

    Sato, Kunihiro; Miyawaki, Fujio

    1992-01-01

    The electrostatic sheath and the heat flow of a two-electron-temperature plasma in the presence of electron emission are investigated analytically. It is shown that the energy flux is markedly enhanced to a value near the electron free-flow energy flux as a result of considerable reduction of the sheath potential due to electron emission if the fraction of hot electrons at the sheath edge is much smaller than one. If the hot- to cold-electron temperature ratio is of the order of ten and the hot electron density is comparable to the cold electron density, the action of the sheath as a thermal insulator is improved as a result of suppression of electron emission due to the space-charge effect of hot electrons. (author)

  14. Low-temperature radiative recombination of electrons with bare nuclei

    International Nuclear Information System (INIS)

    Omidvar, K.

    1993-01-01

    Aside from empirical formulas, the radiative-recombination cross section and coefficient are usually given in tabulated forms instead of analytic formulas. Here, we give analytic expressions in the form of expansions for the recombination cross section as a function of the electron energy E for low E, and for the recombination coefficient as a function of the temperature T for low T. The expansion coefficients are combinations of confluent hypergeometric functions, and are tabulated for a large number of the final principal and angular-momentum quantum numbers n and l. It is shown that the recombination cross section for arbitrary nuclear charge number Z is independent of Z, while the recombination coefficient for T/Z 2 much-lt 1.58x10 5 K increases as Z 2 . Excellent agreement is found with the published tabulated values

  15. Vibrational Spectroscopy of Ionic Liquids.

    Science.gov (United States)

    Paschoal, Vitor H; Faria, Luiz F O; Ribeiro, Mauro C C

    2017-05-24

    Vibrational spectroscopy has continued use as a powerful tool to characterize ionic liquids since the literature on room temperature molten salts experienced the rapid increase in number of publications in the 1990's. In the past years, infrared (IR) and Raman spectroscopies have provided insights on ionic interactions and the resulting liquid structure in ionic liquids. A large body of information is now available concerning vibrational spectra of ionic liquids made of many different combinations of anions and cations, but reviews on this literature are scarce. This review is an attempt at filling this gap. Some basic care needed while recording IR or Raman spectra of ionic liquids is explained. We have reviewed the conceptual basis of theoretical frameworks which have been used to interpret vibrational spectra of ionic liquids, helping the reader to distinguish the scope of application of different methods of calculation. Vibrational frequencies observed in IR and Raman spectra of ionic liquids based on different anions and cations are discussed and eventual disagreements between different sources are critically reviewed. The aim is that the reader can use this information while assigning vibrational spectra of an ionic liquid containing another particular combination of anions and cations. Different applications of IR and Raman spectroscopies are given for both pure ionic liquids and solutions. Further issues addressed in this review are the intermolecular vibrations that are more directly probed by the low-frequency range of IR and Raman spectra and the applications of vibrational spectroscopy in studying phase transitions of ionic liquids.

  16. Modified electron-acoustic and lower-hybrid drift dissipative instability in a two-electron temperature plasma

    International Nuclear Information System (INIS)

    Bose, M.

    1989-01-01

    It is often found, in fusion devices as well as in the auroral ionosphere, that the electrons consist of two distinct group, viz., hot and cold. These two-temperature electron model is sometimes convenient for analytical purposes. Thus the authors have considered a two-temperature electron plasma. In this paper, they investigated analytically the drift dissipative instabilities of modified electron-acoustic and lower-hybrid wve in a two-electron temperature plasma. It is found that the modified electron-acoustic drift dissipative mode are strongly dependent on the number density of cold electrons. From the expression of the growth rate, it is clear that these cold electrons can control the growth of this mode as well

  17. Solitary Langmuir waves in two-electron temperature plasma

    Science.gov (United States)

    Prudkikh, V. V.; Prudkikh

    2014-06-01

    Nonlinear interaction of Langmuir and ion-acoustic waves in two-electron temperature plasma is investigated. New integrable wave interaction regime was discovered, this regime corresponds to the Langmuir soliton with three-hump amplitude, propagating with a speed close to the ion-sound speed in the conditions of strong non-isothermality of electronic components. It was discovered that besides the known analytical solution in the form of one- and two-hump waves, there exists a range of solutions in the form of solitary waves, which in the form of envelope has multi-peak structure and differs from the standard profiles described by hyperbolic functions. In case of fixed plasma parameters, different group velocities correspond to the waves with different number of peaks. It is found that the Langmuir wave package contains both even and uneven numbers of oscillations. Low-frequency potential here has uneven number of peaks. Interrelation of obtained and known earlier results are also discussed.

  18. Low-temperature epitaxy of silicon by electron beam evaporation

    Energy Technology Data Exchange (ETDEWEB)

    Gorka, B. [Hahn-Meitner-Institut Berlin, Kekulestr. 5, 12489 Berlin (Germany); Dogan, P. [Hahn-Meitner-Institut Berlin, Kekulestr. 5, 12489 Berlin (Germany)], E-mail: pinar.dogan@hmi.de; Sieber, I.; Fenske, F.; Gall, S. [Hahn-Meitner-Institut Berlin, Kekulestr. 5, 12489 Berlin (Germany)

    2007-07-16

    In this paper we report on homoepitaxial growth of thin Si films at substrate temperatures T{sub s} = 500-650 deg. C under non-ultra-high vacuum conditions by using electron beam evaporation. Si films were grown at high deposition rates on monocrystalline Si wafers with (100), (110) and (111) orientations. The ultra-violet visible reflectance spectra of the films show a dependence on T{sub s} and on the substrate orientation. To determine the structural quality of the films in more detail Secco etch experiments were carried out. No etch pits were found on the films grown on (100) oriented wafers. However, on films grown on (110) and (111) oriented wafers different types of etch pits could be detected. Films were also grown on polycrystalline silicon (poly-Si) seed layers prepared by an Aluminum-Induced Crystallisation (AIC) process on glass substrates. Electron Backscattering Diffraction (EBSD) shows that the film growth proceeds epitaxially on the grains of the seed layer. But a considerably higher density of extended defects is revealed by Secco etch experiments.

  19. Effect of temperature on the physical properties of 1-butyl-3-methylimidazolium based ionic liquids with thiocyanate and tetrafluoroborate anions, and 1-hexyl-3-methylimidazolium with tetrafluoroborate and hexafluorophosphate anions

    International Nuclear Information System (INIS)

    Vakili-Nezhaad, Gholamreza; Vatani, Mostafa; Asghari, Morteza; Ashour, Ibrahim

    2012-01-01

    Highlights: ► Four ionic liquids named: [BMIM][SCN], [BMIM][BF 4 ], [HMIM][BF 4 ], and [HMIM][PF 6 ] are investigated. ► Density, refractive index, surface tension, dynamic viscosity, and kinematic viscosity of the ionic liquids are measured. ► The measured data was correlated with temperature finding their decrease with rising temperature. ► The volumetric properties of the ionic liquids are calculated from the experimental values of density at T = 298.15 K. ► Correlation between the properties was carried out by the least square method using several empirical equations. - Abstract: The effect of temperature on the physical properties of some ionic liquids was investigated. Density, refractive index, surface tension, dynamic and kinematic viscosities of 1-butyl-3-methylimidazolium based ionic liquids with thiocyanate and tetrafluoroborate, and 1-hexyl-3-methylimidazolium with tetrafluoroborate and hexafluorophosphate anions were measured at various temperatures (density from T = (278.15 to 363.15) K, refractive index from (293.15 to 343.15) K, surface tension from (283.15 to 333.15) K, dynamic viscosity from (283.15 to 368.15) K, and kinematic viscosity from (298.15 to 363.15) K). The volumetric properties for the ionic liquids were also calculated from the experimental values of the density at T = 298.15 K. The Vogel–Fulcher–Tammann (VFT) equation was applied to correlate experimental values of dynamic and kinematic viscosities as a function of temperature. As well, the relation between density and refractive index was correlated satisfactorily with several empirical equations such as Lorentz–Lorenz, Dale–Gladstone, Eykman, Oster, Arago–Biot, Newton and Modified–Eykman. Finally, the relation between surface tension and viscosity was investigated and the parachor method was used to predict density, refractive index and surface tension of the ionic liquids.

  20. Ionic-to-Electronic Conductivity Crossover in CdTe-AgI-As2Te3 Glasses: An 110mAg Tracer Diffusion Study.

    Science.gov (United States)

    Kassem, M; Alekseev, I; Bokova, M; Le Coq, D; Bychkov, E

    2018-04-12

    Conductivity isotherms of (CdTe) x (AgI) 0.5- x/2 (As 2 Te 3 ) 0.5- x/2 glasses (0.0 ≤ x ≤ 0.15) reveal a nonmonotonic behavior with increasing CdTe content reminiscent of mixed cation effect in oxide and chalcogenide glasses. Nevertheless, the apparent similarity appears to be partly incorrect. Using 110m Ag tracer diffusion measurements, we show that semiconducting CdTe additions produce a dual effect: (i) decreasing the Ag + ion transport by a factor of ≈200 with a simultaneous increase of the diffusion activation energy and (ii) increasing the electronic conductivity by 1.5 orders of magnitude. Consequently, the conductivity minimum at x = 0.05 reflects an ionic-to-electronic transport crossover; the silver-ion transport number decreases by 3 orders of magnitude with increasing x.

  1. Estimation of edge electron temperature profiles via forward modelling of the electron cyclotron radiation transport at ASDEX Upgrade

    International Nuclear Information System (INIS)

    Rathgeber, S K; Barrera, L; Eich, T; Fischer, R; Suttrop, W; Wolfrum, E; Nold, B; Willensdorfer, M

    2013-01-01

    We present a method to obtain reliable edge profiles of the electron temperature by forward modelling of the electron cyclotron radiation transport. While for the core of ASDEX Upgrade plasmas, straightforward analysis of electron cyclotron intensity measurements based on the optically thick plasma approximation is usually justified, reasonable analysis of the steep and optically thin plasma edge needs to consider broadened emission and absorption profiles and radiation transport processes. This is carried out in the framework of integrated data analysis which applies Bayesian probability theory for joint analysis of the electron density and temperature with data of different interdependent and complementary diagnostics. By this means, electron cyclotron radiation intensity delivers highly spatially resolved electron temperature data for the plasma edge. In H-mode, the edge gradient of the electron temperature can be several times higher than the one of the radiation temperature. Furthermore, we are able to reproduce the ‘shine-through’ peak—the observation of increased radiation temperatures at frequencies resonant in the optically thin scrape-off layer. This phenomenon is caused by strongly down-shifted radiation of Maxwellian tail electrons located in the H-mode edge region and, therefore, contains valuable information about the electron temperature edge gradient. (paper)

  2. Electronic and ionic transport in Ce0.8PrxTb0.2-xO2-δ and evaluation of performance as oxygen permeation membranes

    DEFF Research Database (Denmark)

    Chatzichristodoulou, Christodoulos; Hendriksen, Peter Vang

    2012-01-01

    is significantly enhanced relative to that of a Ce0.9Gd0.1O1.95-δ membrane at high oxygen activities of the permeate gas (aO2 an > 10-15) due to the enhanced electronic conductivity of the Ce0.8PrxTb0.2-xO2-δ compounds. Interference between the ionic and electronic flows has a significant positive effect......The electronic conductivity of Ce0.8PrxTb0.2-xO2-δ (x = 0, 0.05, 0.10, 0.15, 0.20) was determined in the oxygen activity range aO2 ≈ 103 to aO2 ≈ 10-17 at 700- 900 °C by means of Hebb-Wagner polarisation. The electronic conductivity of all the Ce0.8PrxTb0.2-xO2-δ compositions was significantly...... enhanced as compared to that of Ce0.9Gd0.1O1.95-δ, and its value was found to increase with increasing Pr/Tb ratio. The ionic mobility of Ce0.8PrxTb0.2-xO2-δ is similar to that of Ce1- 2δGd2δO2-δ at the same oxygen vacancy concentration. The calculated oxygen flux of a Ce0.8PrxTb0.2-xO2-δ membrane...

  3. Ion emission from laser-produced plasmas with two electron temperatures

    International Nuclear Information System (INIS)

    Wickens, L.M.; Allen, J.E.; Rumsby, P.T.

    1978-01-01

    An analytic theory for the expansion of a laser-produced plasma with two electron temperatures is presented. It is shown that from the ion-emission velocity spectrum such relevant parameters as the hot- to -cold-electron density ratio, the absolute hot- and cold-electron temperatures, and a sensitive measure of hot- and cold-electron temperature ratio can be deduced. A comparison with experimental results is presented

  4. Development and characterization of high temperature, high energy density dielectric materials to establish routes towards power electronics capacitive devices

    Science.gov (United States)

    Shay, Dennis P.

    -doped composition. The Ca(Ti0.795Mn 0.005Zr0.2)O3 composition was selected for single layer, Pt buried electrode capacitor prototyping to evaluate high temperature electrical characteristics. Polarization-field (P--E) hysteresis measurements of CTZ showed a large increase in dielectric loss with increasing temperature, limiting the dielectric breakdown strength and recoverable energy density. When doped with Mn, CTZ + Mn showed a minimization of the temperature dependence of the breakdown strength, and maximum energy densities of 7.00 J/cm 3 at a Eb of 1.1 MV/cm at room temperature and 5.36 J/cm3 at Eb = 1.0 MV/cm at 300 °C were observed. Impedance spectroscopy of the CTZ and CTZ + Mn dielectrics showed that doping with Mn resulted in a decrease in ionic conductivity and a subsequent decrease in electronic conductivity. Basic characterization of Ca(Ti0.8Hf0.2)O 3 (CTH) and Ca(Ti0.795Mn0.005Hf0.2)O 3 (CTH + Mn) showed similar characteristics compared to the CTZ system. High temperature impedance spectroscopy of CTH and CTH + Mn showed similar behavior to the CTZ and CTZ + Mn systems, but with overall decreases in ionic and electronic conductivity. Coupled with thermally stimulated depolarization current measurements (TSDC), oxygen vacancy migration and space charge conduction are dominant and could be minimized with Mn doping. To gain further insight into how aliovalent Mn controls high temperature conduction in the CTH + Mn system, capacitors were quenched from the sintering temperature and an impedance study was performed. It was observed that ionic conductivity was quenched in due to oxygen vacancies compensating Mn 3+, and interfacial features were observed in impedance spectra due to double back-to-back Schottky barriers (depletion layers). As capacitors were re-oxidized, bulk resistivity increased while interfacial resistivity decreased. The hypothesis was supported by the application of dc bias during impedance measurements, which showed similar impedance behavior to the re

  5. Thermoelectric Generators Based on Ionic Liquids

    Science.gov (United States)

    Laux, Edith; Uhl, Stefanie; Jeandupeux, Laure; López, Pilar Pérez; Sanglard, Pauline; Vanoli, Ennio; Marti, Roger; Keppner, Herbert

    2018-06-01

    Looking at energy harvesting using body or waste heat for portable electronic or on-board devices, Ionic liquids are interesting candidates as thermoactive materials in thermoelectric generators (TEGs) because of their outstanding properties. Two different kinds of ionic liquid, with alkylammonium and choline as cations, were studied, whereby different anions and redox couples were combined. This study focussed on the intention to find non-hazardous and environmentally friendly ionic liquids for TEGs to be selected among the thousands that can potentially be used. Seebeck coefficients (SEs) as high as - 15 mV/K were measured, in a particular case for an electrode temperature difference of 20 K. The bottleneck of our TEG device is still the abundance of negative SE liquids matching the internal resistance with the existing positive SE-liquids at series connections. In this paper, we show further progress in finding increased negative SE liquids. For current extraction from the TEG, the ionic liquid must be blended with a redox couple, allowing carrier exchange in a cyclic process under a voltage which is incuced by the asymmetry of the generator in terms of hot and cold electrodes. In our study, two types of redox pairs were tested. It was observed that a high SE of an ionic liquid/redox blend is not a sufficient condition for high power output. It appears that more complex effects between the ionic liquid and the electrode determine the magnitude of the final current/power output. The physico-chemical understanding of such a TEG cell is not yet available.

  6. Sorption of Ni(II) on GMZ bentonite: effects of pH, ionic strength, foreign ions, humic acid and temperature.

    Science.gov (United States)

    Yang, Shitong; Li, Jiaxing; Lu, Yi; Chen, Yixue; Wang, Xiangke

    2009-09-01

    Bentonite has been widely studied in nuclear waste management because of its special physicochemical properties. In this work, the sorption of Ni(II) from aqueous solution onto GMZ bentonite as a function of contact time, pH, ionic strength, foreign ions, humic acid (HA) and temperature was investigated under ambient conditions. The results indicated that the pseudo-second-order rate equation simulated the kinetic sorption process well. The sorption of Ni(II) on GMZ bentonite was strongly dependent on pH and on ionic strength. At low pH, the sorption of Ni(II) was dominated by outer-sphere surface complexation and ion exchange with Na(+)/H(+) on GMZ bentonite surfaces, whereas inner-sphere surface complexation was the main sorption mechanism at high pH. A positive effect of HA on Ni(II) sorption was found at pH8. The Langmuir, Freundlich, and D-R models were used to simulate the sorption isotherms of Ni(II) at three different temperatures: 303.15, 318.15 and 333.15K. The thermodynamic parameters (DeltaH(0), DeltaS(0) and DeltaG(0)) of Ni(II) sorption on GMZ bentonite at the three different temperatures were calculated from the temperature-dependent sorption isotherms. The results indicated that the sorption process of Ni(II) on GMZ bentonite was endothermic and spontaneous. Experimental results indicate that GMZ bentonite is a suitable sorbent for pre-concentration and solidification of Ni(II) from large volume solutions.

  7. Sorption of Ni(II) on GMZ bentonite: Effects of pH, ionic strength, foreign ions, humic acid and temperature

    International Nuclear Information System (INIS)

    Yang Shitong; Li Jiaxing; Lu Yi; Chen Yixue; Wang Xiangke

    2009-01-01

    Bentonite has been widely studied in nuclear waste management because of its special physicochemical properties. In this work, the sorption of Ni(II) from aqueous solution onto GMZ bentonite as a function of contact time, pH, ionic strength, foreign ions, humic acid (HA) and temperature was investigated under ambient conditions. The results indicated that the pseudo-second-order rate equation simulated the kinetic sorption process well. The sorption of Ni(II) on GMZ bentonite was strongly dependent on pH and on ionic strength. At low pH, the sorption of Ni(II) was dominated by outer-sphere surface complexation and ion exchange with Na + /H + on GMZ bentonite surfaces, whereas inner-sphere surface complexation was the main sorption mechanism at high pH. A positive effect of HA on Ni(II) sorption was found at pH 8. The Langmuir, Freundlich, and D-R models were used to simulate the sorption isotherms of Ni(II) at three different temperatures: 303.15, 318.15 and 333.15 K. The thermodynamic parameters (ΔH 0 , ΔS 0 and ΔG 0 ) of Ni(II) sorption on GMZ bentonite at the three different temperatures were calculated from the temperature-dependent sorption isotherms. The results indicated that the sorption process of Ni(II) on GMZ bentonite was endothermic and spontaneous. Experimental results indicate that GMZ bentonite is a suitable sorbent for pre-concentration and solidification of Ni(II) from large volume solutions.

  8. Electron temperature measurements during electron cyclotron heating on PDX using a ten channel grating polychromator

    International Nuclear Information System (INIS)

    Cavallo, A.; Hsuan, H.; Boyd, D.; Grek, B.; Johnson, D.; Kritz, A.; Mikkelsen, D.; LeBlanc, B.; Takahashi, H.

    1984-10-01

    During first harmonic electron cyclotron heating (ECH) on the Princeton Divertor Experiment (PDX) (R 0 = 137 cm, a = 40 cm), electron temperature was monitored using a grating polychromator which measured second harmonic electron cyclotron emission from the low field side of the tokamak. Interference from the high power heating pulse on the broadband detectors in the grating instrument was eliminated by using a waveguide filter in the transmission line which brought the emission signal to the grating instrument. Off-axis (approx. 4 cm) location of the resonance zone resulted in heating without sawtooth or m = 1 activity. However, heating with the resonance zone at the plasma center caused very large amplitude sawteeth accompanied by strong m = 1 activity: ΔT/T/sub MAX/ approx. = 0.41, sawtooth period approx. = 4 msec, m = 1 period approx. = 90 μ sec, (11 kHz). This is the first time such intense MHD activity driven by ECH has been observed. (For both cases there was no sawtooth activity in the ohmic phase of the discharge before ECH.) At very low densities there is a clear indication that a superthermal electron population is created during ECH

  9. Electron-temperature-gradient-driven drift waves and anomalous electron energy transport

    International Nuclear Information System (INIS)

    Shukla, P.K.; Murtaza, G.; Weiland, J.

    1990-01-01

    By means of a kinetic description for ions and Braginskii's fluid model for electrons, three coupled nonlinear equations governing the dynamics of low-frequency short-wavelength electrostatic waves in the presence of equilibrium density temperature and magnetic-field gradients in a two-component magnetized plasma are derived. In the linear limit a dispersion relation that admits new instabilities of drift waves is presented. An estimate of the anomalous electron energy transport due to non-thermal drift waves is obtained by making use of the saturated wave potential, which is deduced from the mixing-length hypothesis. Stationary solutions of the nonlinear equations governing the interaction of linearly unstable drift waves are also presented. The relevance of this investigation to wave phenomena in space and laboratory plasmas is pointed out. (author)

  10. High-Temperature Electronics: Status and Future Prospects in the 21st Century

    OpenAIRE

    F. Touati; F. Mnif; A. Lawati

    2006-01-01

    This paper reviews the state of current electronics and states the drive toward high-temperature electronics. The problems specific to high-temperature effects on conventional electronics and prospects of alternative technologies like silicon-on-insulator, silicon carbide, and diamond are discussed. Improving petroleum recovery from oil wells with hightemperature coverage of downhole electronics, making combustion processes more efficient utilizing embedded electronics, programs for More Elec...

  11. Prediction of the enthalpies of vaporization for room-temperature ionic liquids: Correlations and a substitution-based additive scheme

    International Nuclear Information System (INIS)

    Kabo, Gennady J.; Paulechka, Yauheni U.; Zaitsau, Dzmitry H.; Firaha, Alena S.

    2015-01-01

    Highlights: • The available literature data on Δ l g H for ionic liquids were analyzed. • Correlation equations for Δ l g H were derived using symbolic regression. • A substitution-based incremental scheme for Δ l g H was developed. • The proposed scheme has an advantage over the existing predictive procedures. - Abstract: The literature data on the enthalpies of vaporization for aprotic ionic liquids (ILs) published by the end of May 2014 were analyzed and the most reliable Δ l g H m values were derived for 68 ILs. The selected enthalpies of vaporization were correlated with density and surface tension using symbolic regression and a number of effective correlation equations were proposed. The substitution-based incremental scheme for prediction of the enthalpies of vaporization of imidazolium, pyridinium and pyrrolidinium ILs was developed. The standard error of the regression for the developed scheme is significantly lower than that for the atom-based group-contribution schemes proposed earlier

  12. Liquid densities and excess molar volumes for (ionic liquids + methanol + water) ternary system at atmospheric pressure and at various temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Deenadayalu, Nirmala [Department of Chemistry, Durban University of Technology, Steve Biko Campus, P.O. Box 1334, Durban, KwaZulu-Natal 4001 (South Africa)], E-mail: NirmalaD@dut.ac.za; Kumar, Satish; Bhujrajh, Pravena [Department of Chemistry, Durban University of Technology, Steve Biko Campus, P.O. Box 1334, Durban, KwaZulu-Natal 4001 (South Africa)

    2007-09-15

    Excess molar volumes, V{sub m}{sup E} have been evaluated from density measurements over the entire composition range for ternary liquid system of ionic liquid (1-ethyl-3-methyl-imidazolium diethylenglycol monomethylether sulphate {l_brace}[EMIM][CH{sub 3}(OCH{sub 2}CH{sub 2}){sub 2}OSO{sub 3}]) (1) + methanol (2) + water (3){r_brace} at T = (298.15, 303.15, and 313.15) K. A vibrating tube densimeter was used for these measurements at atmospheric pressure. The V{sub m}{sup E} values were found to be negative at T = (298.15 and 303.15) K. For {l_brace}[EMIM][CH{sub 3}(OCH{sub 2}CH{sub 2}){sub 2}OSO{sub 3}] (1) + methanol (2) + water (3){r_brace} at T = 313.15 K the V{sub m}{sup E} values become positive at higher mole fraction of ionic liquid and at a corresponding decrease in mole fraction of water. All the experimental data were fitted with the Redlich-Kister equation. The results have also been analysed in term of graph theoretical approach.

  13. Lattice dynamics of ionic crystals

    International Nuclear Information System (INIS)

    Mahan, G.D.

    1990-01-01

    The theory of lattice dynamics for ionic and rare-gas crystals is derived in the harmonic approximation. We start from a Hamiltonian and average over electron coordinates in order to obtain an effective interaction between ion displacements. We assume that electronic excitations are localized on a single ion, which limits the theory to ionic crystals. The deformation-dipole model and the indirect-ionic-interaction model are derived. These two contributions are closely linked, and together provide an accurate description of short-range forces

  14. Electrochemical deposition of magnesium from analogous ionic liquid based on dimethylformamide

    International Nuclear Information System (INIS)

    Wang, Huaiyou; Jia, Yongzhong; Wang, Xiaohua; Yao, Ying; Yue, Duyuan; Jing, Yan

    2013-01-01

    In this paper, a homogeneous, colorless analogous ionic liquid containing dimethylformamide (DMF) and magnesium chloride hexahydrate is synthesized. The conductivity of analogous ionic liquid is measured as a function of temperature and composition. Irreversible electrochemical behavior was generally observed by cyclic voltammetry (CV) in the analogous ionic liquid based electrolytes containing simple Mg salt. CV also shows that the reducing reaction of Mg 2+ is a diffusion control process. Electrochemical impedance spectroscopy (EIS) of analogous ionic liquid was measured at 20 °C, 40 °C and 60 °C. Electrodeposition of magnesium metal from analogous ionic liquid has been studied. The Mg deposits are also systematically characterized by the techniques of powder X-ray diffraction (XRD), scanning electron microscope (SEM) and energy dispersive spectroscopy (EDS). Results showed that magnesium was found in the deposited film

  15. Electron temperature measurements of FRX-C/LSM

    International Nuclear Information System (INIS)

    Rej, D.J.

    1989-01-01

    The electron temperature T/sub e/ has been measured with Thomson scattering field-reversed configurations (FRCs) on the Los Alamos FRX-C/LSM experiment. FRCs formed and trapped in-situ in the θ-pinch source are studied. These experiments mark the first comprehensive FRC T/sub e/ measurements in over five years with data gathered on over 400 discharges. Measurements are performed at a single point in space and time on each discharge. The Thomson scattering diagnostic consist of a Q-switched ruby laser focused from one end to a point 0.2 m from the axial midplane of the θ-pinch coil and at radius of either 0.00 or 0.10 m. Scattered light is collected, dispersed and detected with a 7-channel, triple-grating polychromator configured to detect light wavelengths between 658 and 692 nm. Photomultiplier currents are measured with gated A/D converters, with plasma background signals recorded 100-ns before and 100-ns after the laser pulse. Electron temperatures are measured at either radial position during the time interval, 10 ≤ t ≤ 70 μs, between FRC formation and the onset of the n = 2 instability which usually terminates the discharge. A variety of plasma conditions have been produced by adjusting three external parameters: the initial deuterium fill pressure p/sub O/; the reversed bias magnetic field B/sub b/; and the external magnetic field B/sub w/. The fill-pressure scan has been performed at B/sub b/ ≅ 60 mT and B/sub w/ ≅ 0.4 T with p/sub o/ set at either 2, 3, 4 or 5 mtorr. The bias-field scan, 37 ≤ B/sub b/ ≤ 95 mT, has been performed at p/sub o/ = 3 mtorr and B/sub w/ ≅ 0.4 T. 7 refs., 3 figs., 3 tabs

  16. Ion transport properties of lithium ionic liquids and their ion gels

    International Nuclear Information System (INIS)

    Shobukawa, Hitoshi; Tokuda, Hiroyuki; Susan, Md. Abu Bin Hasan; Watanabe, Masayoshi

    2005-01-01

    A new series of lithium ionic liquids were prepared by introducing of two electron-withdrawing trifluoroacetyl groups in borate salts containing two methoxy-oligo(ethylene oxide) groups in the structures. Successive substitution reactions of oligo-ethylene glycol monomethyl ether and trifluroacetic acid from LiBH 4 yielded the lithium salts, which were clear and colorless liquids at room temperature. The fundamental physicochemical properties, such as density, thermal property, viscosity, ionic conductivity, self-diffusion coefficients, and electrochemical stability, were measured. The lithium ionic liquids had self-dissociation ability and conducted ions even in the absence of organic solvents. New polymer electrolytes, named 'ion gels', were prepared by radical cross-linking reactions of a poly(ethylene oxide-co-propylene oxide)tri-acrylate macromonomer in the presence the lithium ionic liquid. An increase in the glass transition temperatures (T g ) of the ion gels was very small even with increasing lithium ionic liquid concentration, and the T g 's were lower than that of the ionic liquid itself. The ionic conductivity of the ion gels surpassed that of the lithium ionic liquid in the bulk at certain compositions

  17. 500 C Electronic Packaging and Dielectric Materials for High Temperature Applications

    Science.gov (United States)

    Chen, Liang-yu; Neudeck, Philip G.; Spry, David J.; Beheim, Glenn M.; Hunter, Gary W.

    2016-01-01

    High-temperature environment operable sensors and electronics are required for exploring the inner solar planets and distributed control of next generation aeronautical engines. Various silicon carbide (SiC) high temperature sensors, actuators, and electronics have been demonstrated at and above 500C. A compatible packaging system is essential for long-term testing and application of high temperature electronics and sensors. High temperature passive components are also necessary for high temperature electronic systems. This talk will discuss ceramic packaging systems developed for high temperature electronics, and related testing results of SiC circuits at 500C and silicon-on-insulator (SOI) integrated circuits at temperatures beyond commercial limit facilitated by these high temperature packaging technologies. Dielectric materials for high temperature multilayers capacitors will also be discussed. High-temperature environment operable sensors and electronics are required for probing the inner solar planets and distributed control of next generation aeronautical engines. Various silicon carbide (SiC) high temperature sensors, actuators, and electronics have been demonstrated at and above 500C. A compatible packaging system is essential for long-term testing and eventual applications of high temperature electronics and sensors. High temperature passive components are also necessary for high temperature electronic systems. This talk will discuss ceramic packaging systems developed for high electronics and related testing results of SiC circuits at 500C and silicon-on-insulator (SOI) integrated circuits at temperatures beyond commercial limit facilitated by high temperature packaging technologies. Dielectric materials for high temperature multilayers capacitors will also be discussed.

  18. The effects of temperature and alkyl chain length on the density and surface tension of the imidazolium-based geminal dicationic ionic liquids

    International Nuclear Information System (INIS)

    Moosavi, Majid; Khashei, Fatemeh; Sharifi, Ali; Mirzaei, Mojtaba

    2017-01-01

    Highlights: • Surface tension and density of three GDILs were measured at different temperatures. • Surface entropy and surface enthalpy indicate the surface ordering in these GDILs. • Parachors and critical temperatures of these systems were estimated. • Results of GDILs were compared with the results of corresponding traditional MILs. • Relations between surface tension, density and viscosity of GDILs were demonstrated. - Abstract: Surface tensions and densities of three imidazolium-based geminal dicationic ionic liquids (GDILs) with the bis(trifluoromethylsulfonyl)imide, [NTf 2 ] − , as a common anion, have been measured at ambient pressure at different temperatures in the range from 296.00 to 353.15 K. The surface thermodynamic functions such as surface entropy and surface enthalpy were derived from the temperature dependence of surface tension which indicated the surface ordering in these GDILs. As well as the parachor, the critical temperatures of these systems have been estimated using the Guggenheim and Eotvos correlations. In each case, the results of GDILs have been compared with the results of corresponding traditional monocationic ILs (MILs). Also, the relations between the surface tension and density and also surface tension and viscosity data have been demonstrated and discussed.

  19. Temperature dependence of electron mean free path in molybdenum from ultrasonic measurements

    Energy Technology Data Exchange (ETDEWEB)

    Almond, D P; Detwiler, D A; Rayne, J A [Carnegie-Mellon Univ., Pittsburgh, Pa. (USA)

    1975-09-08

    The temperature dependence of the electronic mean free path in molybdenum has been obtained from ultrasonic attenuation measurements.For temperature up to 30 K a T/sup -2/ law is followed suggesting the importance of electron-electron scattering in the attenuation mechanism.

  20. Removal of radiocobalt from aqueous solutions by kaolinite affected by solid content, pH, ionic strength, contact time and temperature

    International Nuclear Information System (INIS)

    Kan Li; Zhengjie Liu; Lei Chen; Yunhui Dong; Jun Hu; Chinese Academy of Sciences, Hefei

    2013-01-01

    The kaolinite sample was characterized by Fourier transform infrared spectroscopy (FT-IR) and X-ray powder diffraction, and was applied as adsorbent for the removal of radiocobalt ions from radioactive wastewater. The results demonstrated that the sorption of Co(II) was strongly dependent on pH and ionic strength at low pH values, and independent of pH and ionic strength at high pH values. The sorption of Co(II) was dominated by outer-sphere surface complexation or ion exchange at low pH values, whereas inner-sphere surface complexation was the main sorption mechanism at high pH values. The sorption isotherms were well described by Langmuir, Freundlich and Dubinin-Radushkevich models. The thermodynamic parameters (i.e., ΔGdeg, ΔSdeg, ΔHdeg) calculated from the temperature-dependent sorption isotherms indicated that the sorption of Co(II) on kaolinite was an endothermic and spontaneous process. The results of high sorption capacity of kaolinite suggested that the kaolinite sample was a suitable material for the preconcentration of Co(II) from large volumes of aqueous solutions and as backfill materials in nuclear waste management. (author)

  1. Sorption properties of Th(IV) on the raw diatomite-Effects of contact time, pH, ionic strength and temperature

    Energy Technology Data Exchange (ETDEWEB)

    Sheng Guodong; Hu Jun [Institute of Plasma Physics, Chinese Academy of Sciences, P.O. Box 1126, Hefei 230031 (China); Wang Xiangke [Institute of Plasma Physics, Chinese Academy of Sciences, P.O. Box 1126, Hefei 230031 (China)], E-mail: xkwang@ipp.ac.cn

    2008-10-15

    Diatomite has a number of unique physicochemical properties and has diversified industrial uses. Natural diatomite has been tested as a potential sorbent for the removal of Th(IV) from aqueous solutions. The results indicate that sorption of Th(IV) is strongly dependent on ionic strength at pH<3, and is independent of ionic strength at pH>3. Outer-sphere complexation or ion exchange may be the main sorption mechanism of Th(IV) to diatomite at low pH values, whereas the sorption of Th(IV) at pH>3 is mainly dominated by inner-sphere complexation or precipitation. The competition for Th(IV) between aqueous or surface adsorbed anions (e.g., herein ClO{sub 4}{sup -}, NO{sub 3}{sup -} and Cl{sup -}) and surface functional groups of diatomite is important for Th(IV) sorption. The thermodynamic data ({delta}H{sup 0}, {delta}S{sup 0}, {delta}G{sup 0}) are calculated from the temperature-dependent sorption isotherms. The results suggest that sorption process of Th(IV) on diatomite is spontaneous and endothermic.

  2. Biosorption removal of benzene and toluene by three dried macroalgae at different ionic strength and temperatures: Algae biochemical composition and kinetics.

    Science.gov (United States)

    Flores-Chaparro, Carlos E; Chazaro Ruiz, Luis Felipe; Alfaro de la Torre, Ma Catalina; Huerta-Diaz, Miguel Angel; Rangel-Mendez, Jose Rene

    2017-05-15

    Release of low-molecular aromatic hydrocarbons (HC) into natural waters brings severe consequences to our environment. Unfortunately very limited information is available regarding the treatment of these pollutants. This work evaluated the use of brown, green and red macroalgae biomass as biosorbents of benzene and toluene, two of the most soluble HC. Raw seaweed biomasses were completely characterized, then evaluated under different temperatures and ionic strengths to assess their potential as biosorbents and to elucidate the biosorption mechanisms involved. Brown macroalgae registered the highest removal capacities for benzene and toluene (112 and 28 mg·g -1 , respectively), and these were not affected at ionic strength < 0.6 M. Langmuir and Sips isotherm equations well described biosorption data, and the pseudo-second order model provided the best fit to the kinetics rate. Hydrocarbons are adsorbed onto the diverse chemical components of the cell wall by London forces and hydrophobic interactions. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. Debye temperatures of uranium chalcogenides from their lattice ...

    Indian Academy of Sciences (India)

    Unknown

    From the phonon frequencies, their Debye temperatures are evaluated. Further, ... Keywords. Uranium chalcogenides; p-wave electronic superconductor; phonon frequency; Debye tempera- ture; spin ... to the ionic crystals of similar structure.

  4. Electron temperatures of inductively coupled Cl2-Ar plasmas

    International Nuclear Information System (INIS)

    Fuller, N.C.M.; Donnelly, Vincent M.; Herman, Irving P.

    2002-01-01

    Trace rare gases optical emission spectroscopy has been used to measure the electron temperature, T e , in a high-density inductively coupled Cl 2 -Ar plasma at 18 mTorr as function of the 13.56 MHz radio frequency power and Ar fraction. Only the Kr and Xe emission lines were used to determine T e , because of evidence of radiation trapping when the Ar emission lines were also used for larger Ar fractions. At 600 W (10.6 W cm-2), T e increases from ∼4.0±0.5 eV to ∼6.0±2.0 eV as the Ar fraction increases from 1% to 96%. In the H (inductive, bright) mode, T e , for a 'neat' chlorine plasma (including 1% of each He/Ne/Ar/Kr/Xe) increases only slightly from ∼3.8 to 4.0 eV as power increases from 450 to 750 W. This increase is much larger for larger Ar fractions, such as from ∼4.0 to 7.3 eV for 78% Ar. Most of these effects can be understood using the fundamental particle balance equation

  5. Rf breakdown studies in room temperature electron linac structures

    International Nuclear Information System (INIS)

    Loew, G.A.; Wang, J.W.

    1988-05-01

    This paper is an overall review of studies carried out by the authors and some of their colleagues on RF breakdown, Field Emission and RF processing in room temperature electron linac structure. The motivation behind this work is twofold: in a fundamental way, to contribute to the understanding of the RF breakdown phenomenon, and as an application, to determine the maximum electric field gradient that can be obtained and used safely in future e/sup +-/ linear colliders. Indeed, the next generation of these machines will have to reach into the TeV (10 12 eV) energy range, and the accelerating gradient will be to be of the crucial parameters affecting their design, construction and cost. For a specified total energy, the gradient sets the accelerator length, and once the RF structure, frequency and pulse repetition rate are selected, it also determines the peak and average power consumption. These three quantities are at the heart of the ultimate realizability and cost of these accelerators. 24 refs., 19 figs., 4 tabs

  6. Carprofen-imprinted monolith prepared by reversible addition-fragmentation chain transfer polymerization in room temperature ionic liquids.

    Science.gov (United States)

    Ban, Lu; Han, Xu; Wang, Xian-Hua; Huang, Yan-Ping; Liu, Zhao-Sheng

    2013-10-01

    To obtain fast separation, ionic liquids were used as porogens first in combination with reversible addition-fragmentation chain transfer (RAFT) polymerization to prepare a new type of molecularly imprinted polymer (MIP) monolith. The imprinted monolithic column was synthesized using a mixture of carprofen (template), 4-vinylpyridine, ethylene glycol dimethacrylate, [BMIM]BF4, and chain transfer agent (CTA). Some polymerization factors, such as template-monomer molar ratio, the degree of crosslinking, the composition of the porogen, and the content of CTA, on the column efficiency and imprinting effect of the resulting MIP monolith were systematically investigated. Affinity screening of structurally similar compounds with the template can be achieved in 200 s on the MIP monolith due to high column efficiency (up to 12,070 plates/m) and good column permeability. Recognition mechanism of the imprinted monolith was also investigated.

  7. Electron energy distribution function, effective electron temperature, and dust charge in the temporal afterglow of a plasma

    International Nuclear Information System (INIS)

    Denysenko, I. B.; Azarenkov, N. A.; Kersten, H.

    2016-01-01

    Analytical expressions describing the variation of electron energy distribution function (EEDF) in an afterglow of a plasma are obtained. Especially, the case when the electron energy loss is mainly due to momentum-transfer electron-neutral collisions is considered. The study is carried out for different EEDFs in the steady state, including Maxwellian and Druyvesteyn distributions. The analytical results are not only obtained for the case when the rate for momentum-transfer electron-neutral collisions is independent on electron energy but also for the case when the collisions are a power function of electron energy. Using analytical expressions for the EEDF, the effective electron temperature and charge of the dust particles, which are assumed to be present in plasma, are calculated for different afterglow durations. An analytical expression for the rate describing collection of electrons by dust particles for the case when the rate for momentum-transfer electron-neutral collisions is independent on electron energy is also derived. The EEDF profile and, as a result, the effective electron temperature and dust charge are sufficiently different in the cases when the rate for momentum-transfer electron-neutral collisions is independent on electron energy and when the rate is a power function of electron energy.

  8. POSS Ionic Liquid.

    Science.gov (United States)

    Tanaka, Kazuo; Ishiguro, Fumiyasu; Chujo, Yoshiki

    2010-12-22

    We report the synthesis of a stable room-temperature ionic liquid consisting of an octacarboxy polyhedral oligomeric silsesquioxane (POSS) anion and an imidazolium cation. The introduction of the POSS moiety enhances the thermal stability and reduces the melting temperature. From an evaluation of the thermodynamic parameters during the melting, it was found that the rigidity and cubic structure of POSS can contribute to the enhancement of these thermal properties.

  9. Electron temperature measurement in Maxwellian non-isothermal beam plasma of an ion thruster

    International Nuclear Information System (INIS)

    Zhang, Zun; Tang, Haibin; Kong, Mengdi; Zhang, Zhe; Ren, Junxue

    2015-01-01

    Published electron temperature profiles of the beam plasma from ion thrusters reveal many divergences both in magnitude and radial variation. In order to know exactly the radial distributions of electron temperature and understand the beam plasma characteristics, we applied five different experimental approaches to measure the spatial profiles of electron temperature and compared the agreement and disagreement of the electron temperature profiles obtained from these techniques. Experimental results show that the triple Langmuir probe and adiabatic poly-tropic law methods could provide more accurate space-resolved electron temperature of the beam plasma than other techniques. Radial electron temperature profiles indicate that the electrons in the beam plasma are non-isothermal, which is supported by a radial decrease (∼2 eV) of electron temperature as the plume plasma expands outward. Therefore, the adiabatic “poly-tropic law” is more appropriate than the isothermal “barometric law” to be used in electron temperature calculations. Moreover, the calculation results show that the electron temperature profiles derived from the “poly-tropic law” are in better agreement with the experimental data when the specific heat ratio (γ) lies in the range of 1.2-1.4 instead of 5/3

  10. Model of electron capture in low-temperature glasses

    International Nuclear Information System (INIS)

    Bartczak, W.M.; Swiatla, D.; Kroh, J.

    1983-01-01

    The new model of electron capture by a statistical variety of traps in glassy matrices is proposed. The electron capture is interpreted as the radiationless transition (assisted by multiphonon emission) of the mobile electron to the localized state in the trap. The conception of 'unfair' and 'fair' traps is introduced. The 'unfair' trap captures the mobile electron by the shallow excited state. In contrast, the 'fair' trap captures the electron by the ground state. The model calculations of the statistical distributions of the occupied electron traps are presented and discussed with respect to experimental results. (author)

  11. New insights into the interface between a single-crystalline metal electrode and an extremely pure ionic liquid: slow interfacial processes and the influence of temperature on interfacial dynamics.

    Science.gov (United States)

    Drüschler, Marcel; Borisenko, Natalia; Wallauer, Jens; Winter, Christian; Huber, Benedikt; Endres, Frank; Roling, Bernhard

    2012-04-21

    Ionic liquids are of high interest for the development of safe electrolytes in modern electrochemical cells, such as batteries, supercapacitors and dye-sensitised solar cells. However, electrochemical applications of ionic liquids are still hindered by the limited understanding of the interface between electrode materials and ionic liquids. In this article, we first review the state of the art in both experiment and theory. Then we illustrate some general trends by taking the interface between the extremely pure ionic liquid 1-butyl-1-methylpyrrolidinium tris(pentafluoroethyl)trifluorophosphate and an Au(111) electrode as an example. For the study of this interface, electrochemical impedance spectroscopy was combined with in situ STM and in situ AFM techniques. In addition, we present new results for the temperature dependence of the interfacial capacitance and dynamics. Since the interfacial dynamics are characterised by different processes taking place on different time scales, the temperature dependence of the dynamics can only be reliably studied by recording and carefully analysing broadband capacitance spectra. Single-frequency experiments may lead to artefacts in the temperature dependence of the interfacial capacitance. We demonstrate that the fast capacitive process exhibits a Vogel-Fulcher-Tamman temperature dependence, since its time scale is governed by the ionic conductivity of the ionic liquid. In contrast, the slower capacitive process appears to be Arrhenius activated. This suggests that the time scale of this process is determined by a temperature-independent barrier, which may be related to structural reorganisations of the Au surface and/or to charge redistributions in the strongly bound innermost ion layer. This journal is © the Owner Societies 2012

  12. Ionic liquid-based observation technique for nonconductive materials in the scanning electron microscope: Application to the characterization of a rare earth ore.

    Science.gov (United States)

    Brodusch, Nicolas; Waters, Kristian; Demers, Hendrix; Gauvin, Raynald

    2014-03-01

    A new approach for preparing geological materials is proposed to reduce charging during their characterization in a scanning electron microscope. This technique was applied to a sample of the Nechalacho rare earth deposit, which contains a significant amount of the minerals fergusonite and zircon. Instead of covering the specimen surface with a conductive coating, the sample was immersed in a dilute solution of ionic liquid and then air dried prior to SEM analysis. Imaging at a wide range of accelerating voltages was then possible without evidence of charging when using the in-chamber secondary and backscattered electrons detectors, even at 1 kV. High resolution x-ray and electron backscatter diffraction mapping were successfully obtained at 20 and 5 kV with negligible image drifting and permitted the characterization of the microstructure of the zircon/fergusonite-Y aggregates encased in the matrix minerals. Because of the absence of a conductive layer at the surface of the specimen, the Kikuchi band contrast was improved and the backscatter electron signal increased at both 5 and 20 kV as confirmed by Monte Carlo modeling. These major developments led to an improvement of the spatial resolution and efficiency of the above characterization techniques applied to the rare earth ore and it is expected that they can be applied to other types of ores and minerals. Copyright © 2014 Wiley Periodicals, Inc.

  13. Effect of alkyl chain length and temperature on the thermodynamic properties of ionic liquids 1-alkyl-3-methylimidazolium bromide in aqueous and non-aqueous solutions at different temperatures

    International Nuclear Information System (INIS)

    Sadeghi, Rahmat; Shekaari, Hemayat; Hosseini, Rahim

    2009-01-01

    The alkyl chain length of 1-alkyl-3-methylimidazolium bromide ([Rmim][Br], R = propyl (C 3 ), hexyl (C 6 ), heptyl (C 7 ), and octyl (C 8 )) was varied to prepare a series of room-temperature ionic liquids (RTILs), and experimental measurements of density and speed of sound at different temperatures ranging from (288.15 to 308.15) K for their aqueous and methanolic solutions in the dilute concentration region (0.01 to 0.30) mol . kg -1 were taken. The values of the compressibilities, expansivity and apparent molar properties for [C n mim][Br] in aqueous and methanolic solutions were determined at the investigated temperatures. The obtained apparent molar volumes and apparent molar isentropic compressibilities were fitted to the Redlich-Mayer and the Pitzer's equations from which the corresponding infinite dilution molar properties were obtained. The values of the infinite dilution molar properties were used to obtain some information about solute-solvent and solute-solute interactions. The thermodynamic properties of investigated ionic liquids in aqueous solutions have been compared with those in methanolic solutions. Also, the comparison between thermodynamic properties of investigated solutions and those of electrolyte solutions, polymer solutions, cationic surfactant solutions and tetraalkylammonium salt solutions have been made

  14. Effect of alkyl chain length and temperature on the thermodynamic properties of ionic liquids 1-alkyl-3-methylimidazolium bromide in aqueous and non-aqueous solutions at different temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Sadeghi, Rahmat [Department of Chemistry, University of Kurdistan, Sanandaj (Iran, Islamic Republic of)], E-mail: rahsadeghi@yahoo.com; Shekaari, Hemayat [Department of Chemistry, Faculty of Science, University of Mohaghegh Ardabili, Ardabil (Iran, Islamic Republic of); Hosseini, Rahim [Department of Chemistry, University of Kurdistan, Sanandaj (Iran, Islamic Republic of)

    2009-02-15

    The alkyl chain length of 1-alkyl-3-methylimidazolium bromide ([Rmim][Br], R = propyl (C{sub 3}), hexyl (C{sub 6}), heptyl (C{sub 7}), and octyl (C{sub 8})) was varied to prepare a series of room-temperature ionic liquids (RTILs), and experimental measurements of density and speed of sound at different temperatures ranging from (288.15 to 308.15) K for their aqueous and methanolic solutions in the dilute concentration region (0.01 to 0.30) mol . kg{sup -1} were taken. The values of the compressibilities, expansivity and apparent molar properties for [C{sub n}mim][Br] in aqueous and methanolic solutions were determined at the investigated temperatures. The obtained apparent molar volumes and apparent molar isentropic compressibilities were fitted to the Redlich-Mayer and the Pitzer's equations from which the corresponding infinite dilution molar properties were obtained. The values of the infinite dilution molar properties were used to obtain some information about solute-solvent and solute-solute interactions. The thermodynamic properties of investigated ionic liquids in aqueous solutions have been compared with those in methanolic solutions. Also, the comparison between thermodynamic properties of investigated solutions and those of electrolyte solutions, polymer solutions, cationic surfactant solutions and tetraalkylammonium salt solutions have been made.

  15. dual – temperature electron distribution in a laboratory plasma

    African Journals Online (AJOL)

    DEVEERERRY

    continuum, calculations show that a collision transition between close neighbouring ... depend on the energy distribution of free electrons but on both the excitation and ..... Germany. Postma, A. J., 1969. Calculated electron energy distribution ...

  16. Criteria governing electron plasma waves in a two-temperature plasma

    International Nuclear Information System (INIS)

    Dell, M.P.; Gledhill, I.M.A.; Hellberg, M.A.

    1987-01-01

    Using a technique based on the saddle-points of the dielectric function, criteria are found which govern the behaviour of electron plasma waves in plasmas with two electron populations having different temperatures. (orig.)

  17. The impact of edge gradients in the pressure, density, ion temperature, and electron temperature on edge-localized modes

    International Nuclear Information System (INIS)

    Kleva, Robert G.; Guzdar, Parvez N.

    2011-01-01

    The magnitude of the energy and particle fluxes in simulations of edge-localized modes (ELMs) is determined by the edge gradients in the pressure, density, ion temperature, and electron temperature. The total edge pressure gradient is the dominant influence on ELMs by far. An increase (decrease) of merely 2% in the pressure gradient results in an increase (decrease) of more than a factor of ten in the size of the ELM bursts. At a fixed pressure gradient, the size of the ELM bursts decreases as the density gradient increases, while the size of the bursts increases as the electron temperature gradient or, especially, the ion temperature gradient increases.

  18. Instability and transport driven by an electron temperature gradient close to critical

    International Nuclear Information System (INIS)

    Dong, J.Q.; Jian, G.D.; Wang, A.K.; Sanuki, H.; Itoh, K.

    2003-01-01

    Electron temperature gradient (ETG) driven instability in toroidal plasmas is studied with gyrokinetic theory. The full electron kinetics is considered. The upgraded numerical scheme for solving the integral eigenvalue equations allows the study of both growing and damping modes, and thus direct calculation of critical gradient. Algebraic formulas for the critical gradient with respect to ratio of electron temperature over ion temperature and to toroidicity are given. An estimation for turbulence induced transport is presented. (author)

  19. Production of CNT-taxol-embedded PCL microspheres using an ammonium-based room temperature ionic liquid: as a sustained drug delivery system.

    Science.gov (United States)

    Kim, Seong Yeol; Hwang, Ji-Young; Seo, Jae-Won; Shin, Ueon Sang

    2015-03-15

    We describe a one-pot method for the mass production of polymeric microspheres containing water-soluble carbon-nanotube (w-CNT)-taxol complexes using an ammonium-based room temperature ionic liquid. Polycaprolactone (PCL), trioctylmethylammonium chloride (TOMAC; liquid state from -20 to 240°C), and taxol were used, respectively, as a model polymer, room temperature ionic liquid, and drug. Large quantities of white colored PCL powder without w-CNT-taxol complexes and gray colored PCL powders containing w-CNT-taxol (1:1 or 1:2 wt/wt) complexes were produced by phase separation between the hydrophilic TOMAC and the hydrophobic PCL. Both microsphere types had a uniform, spherical structure of average diameter 3-5μm. The amount of taxol embedded in PCL microspheres was determined by HPLC and (1)H NMR to be 8-12μg per 1.0mg of PCL (loading capacity (LC): 0.8-1.2%; entrapment efficiency (EE): 16-24%). An in vitro HPLC release assay showed sustain release of taxol without an initial burst over 60days at an average rate of 0.003-0.0073mg per day. The viability patterns of human breast cancer cells (MCF-7) for PCTx-1 and -2 showed dose-dependent inhibitory effects. In the presence of PCTx-1 and -2, the MCF-7 cells showed high viability in the concentration level of, respectably, <70 and <5μg/mL. Copyright © 2014 Elsevier Inc. All rights reserved.

  20. Initial deposition and electron paramagnetic resonance defects characterization of TiO{sub 2} films prepared using successive ionic layer adsorption and reaction method

    Energy Technology Data Exchange (ETDEWEB)

    Wu Yiyong, E-mail: wuyiyong2001@yahoo.com.cn [National Key Laboratory of Materials Behaviors and Evaluation Technology in Space Environments, Harbin Institute of Technology, P.O. 432, Nan gang District, Harbin, 150080 (China); Shi Yaping [National Key Laboratory of Materials Behaviors and Evaluation Technology in Space Environments, Harbin Institute of Technology, P.O. 432, Nan gang District, Harbin, 150080 (China); Harbin University of Commerce, P.O. 493, Song bei District, Harbin, 150028 (China); Xu Xianbin; Sun Chengyue [National Key Laboratory of Materials Behaviors and Evaluation Technology in Space Environments, Harbin Institute of Technology, P.O. 432, Nan gang District, Harbin, 150080 (China)

    2012-06-01

    Successive ionic layer adsorption and reaction (SILAR) technique was considered promisingly to deposit ultra thin titanium dioxide (TiO{sub 2}) films under ambient condition. In this paper, the growth process, structures and paramagnetic defects of the films were characterized by complementary techniques of atomic force microscopy, X-ray photoelectron spectroscopy, Raman spectroscopy and electron paramagnetic resonance spectroscopy. The results indicate that on glass substrate the SILAR TiO{sub 2} film nucleates in an island mode within the initial five deposition cycles but grows in a layer-by-layer mode afterwards. The growth rate was measured as 4.6 A/cycle. In the as-deposited films, a kind of paramagnetic defects is detected at g (2.0029) and it can be attributed to oxygen vacancies. These as-received oxygen vacancies could be annealed out at 473 K. Ultraviolet irradiation on the as-deposited films can also decrease the density of the defects. The relative mechanisms on the phenomenon were discussed in this paper. - Highlights: Black-Right-Pointing-Pointer TiO{sub 2} films are deposited on glass at 25 Degree-Sign C by successive ionic layer adsorption and reaction method with a rate of 4.6 A/cycle. Black-Right-Pointing-Pointer The films nucleate in an island mode initially but grow in a layer mode afterwards. Black-Right-Pointing-Pointer The SILAR TiO{sub 2} films nucleation period is five cycles. Black-Right-Pointing-Pointer Electron paramagnetic resonance spectroscopy shows that TiO{sub 2} films paramagnetic defects are attributed to oxygen vacancies. Black-Right-Pointing-Pointer They will decrease by anneal or ultraviolet radiation and form hydroxyl or superoxide radicals.

  1. Initial deposition and electron paramagnetic resonance defects characterization of TiO2 films prepared using successive ionic layer adsorption and reaction method

    International Nuclear Information System (INIS)

    Wu Yiyong; Shi Yaping; Xu Xianbin; Sun Chengyue

    2012-01-01

    Successive ionic layer adsorption and reaction (SILAR) technique was considered promisingly to deposit ultra thin titanium dioxide (TiO 2 ) films under ambient condition. In this paper, the growth process, structures and paramagnetic defects of the films were characterized by complementary techniques of atomic force microscopy, X-ray photoelectron spectroscopy, Raman spectroscopy and electron paramagnetic resonance spectroscopy. The results indicate that on glass substrate the SILAR TiO 2 film nucleates in an island mode within the initial five deposition cycles but grows in a layer-by-layer mode afterwards. The growth rate was measured as 4.6 Å/cycle. In the as-deposited films, a kind of paramagnetic defects is detected at g (2.0029) and it can be attributed to oxygen vacancies. These as-received oxygen vacancies could be annealed out at 473 K. Ultraviolet irradiation on the as-deposited films can also decrease the density of the defects. The relative mechanisms on the phenomenon were discussed in this paper. - Highlights: ► TiO 2 films are deposited on glass at 25 °C by successive ionic layer adsorption and reaction method with a rate of 4.6 Å/cycle. ► The films nucleate in an island mode initially but grow in a layer mode afterwards. ► The SILAR TiO 2 films nucleation period is five cycles. ► Electron paramagnetic resonance spectroscopy shows that TiO 2 films paramagnetic defects are attributed to oxygen vacancies. ► They will decrease by anneal or ultraviolet radiation and form hydroxyl or superoxide radicals.

  2. Evaluation of COTS Electronic Parts for Extreme Temperature Use in NASA Missions

    Science.gov (United States)

    Patterson, Richard L.; Hammoud, Ahmad; Elbuluk, Malik

    2008-01-01

    Electronic systems capable of extreme temperature operation are required for many future NASA space exploration missions where it is desirable to have smaller, lighter, and less expensive spacecraft and probes. Presently, spacecraft on-board electronics are maintained at about room temperature by use of thermal control systems. An Extreme Temperature Electronics Program at the NASA Glenn Research Center focuses on development of electronics suitable for space exploration missions. The effects of exposure to extreme temperatures and thermal cycling are being investigated for commercial-off-the-shelf components as well as for components specially developed for harsh environments. An overview of this program along with selected data is presented.

  3. Production of a large diameter ECR plasma with low electron temperature

    International Nuclear Information System (INIS)

    Koga, Mayuko; Hishikawa, Yasuhiro; Tsuchiya, Hayato; Kawai, Yoshinobu

    2006-01-01

    A large diameter plasma over 300 mm in diameter is produced by electron cyclotron resonance (ECR) discharges using a cylindrical vacuum chamber of 400 mm in inner diameter. It is found that the plasma uniformity is improved by adding the nitrogen gas to pure Ar plasma. The electron temperature is decreased by adding the nitrogen gas. It is considered that the electron energy is absorbed in the vibrational energy of nitrogen molecules and the electron temperature decreases. Therefore, the adjunction of the nitrogen gas is considered to be effective for producing uniform and low electron temperature plasma

  4. Ionic liquids, tuneable solvents for intensifying reactions and separations

    NARCIS (Netherlands)

    Meindersma, G.W.; Kuipers, N.J.M.; Haan, de A.B.

    2007-01-01

    An Ionic Liquid (IL), or a Room Temperature Ionic Liquid (RTIL), is commonly defined as a liquid entirely composed of ions, which is a fluid below 100 °C. Due to the fact that an ionic liquid is a salt, it has a negligible vapour pressure. Therefore, ionic liquids are not volatile at ambient process

  5. Variations in erosive wear of metallic materials with temperature via the electron work function

    International Nuclear Information System (INIS)

    Huang, Xiaochen; Yu, Bin; Yan, X.G.; Li, D.Y.

    2016-01-01

    Mechanical properties of metals are intrinsically determined by their electron behavior, which is largely reflected by the electron work function (EWF or φ). Since the work function varies with temperature, the dependence of material properties on temperature could be predicted via variations in work function with temperature. Combining a hardness – φ relationship and the dependence of work function on temperature, a temperature-dependent model for predicting solid-particle erosion is proposed. Erosive wear losses of copper, nickel, and carbon steel as sample materials were measured at different temperatures. Results of the tests are consistent with the theoretical prediction. This study demonstrates a promising parameter, electron work function, for looking into fundamental aspects of wear phenomena, which would also help develop alternative methodologies for material design. - Highlights: • Metallic materials' wear resistance is influenced by temperature. • Electron work function (EWF) intrinsically determines materials' wear resistance. • An EWF-based temperature-dependent solid-particle erosion model is proposed.

  6. Preparation and transport properties of novel lithium ionic liquids

    International Nuclear Information System (INIS)

    Shobukawa, Hitoshi; Tokuda, Hiroyuki; Tabata, Sei-Ichiro; Watanabe, Masayoshi

    2004-01-01

    Novel lithium salts of borates having two electron-withdrawing groups (either 1,1,1,3,3,3-hexafluoro-2-propoxy or pentafluorophenoxy group) and two methoxy-oligo(ethylene oxide) groups (number of repeating unit: n = 3, 4, 7.2) were prepared by successive substitution-reactions from LiBH 4 . The obtained lithium salts were clear and colorless liquids at room temperature. The density, thermal property, viscosity, and ionic conductivity were measured for the lithium ionic liquids. The pulsed-gradient spin-echo NMR (PGSE-NMR) method was used to independently determine self-diffusion coefficients of the lithium cation ( 7 Li NMR) and the anion ( 19 F NMR) in the bulk. The ionic conductivity of the new lithium salts was 10 -5 to 10 -4 S cm -1 at 30 deg. C, which was lower than that of typical ionic liquids by two orders of magnitude. However, the degree of self-dissociation of the lithium ionic liquids; the ratio of the molar conductivity determined by the complex impedance method to that calculated from the self-diffusion coefficients and the Nernst-Einstein equation, ranged from 0.1 to 0.4, which are comparable values to those of a highly dissociable salt in an aprotic polar solvent and of typical ionic liquids. The main reason for the meager conductivity was high viscosities of the lithium ionic liquids. It should be noted that the lithium ionic liquids have self-dissociation ability and conduct the ions in the absence of organic solvents

  7. Probing electron density of H-bonding between cation-anion of imidazolium-based ionic liquids with different anions by vibrational spectroscopy.

    Science.gov (United States)

    Gao, Yan; Zhang, Liqun; Wang, Yong; Li, Haoran

    2010-03-04

    Attenuated total reflection infrared spectroscopy and density functional theory calculation have been employed to study the spectral properties of imidazolium-based ionic liquids (ILs) with different anions. ILs based on 1-butyl-3-methylimidazolium cation with different anions, OH(-), CF(3)CO(2)(-), HSO(4)(-), H(2)PO(4)(-), Cl(-), PF(6)(-), and BF(4)(-), are investigated in the present work. It has been shown that the C(2)-H stretching vibration of the imidazolium ring is closely related to the electron density of H-bonding between the two closest cations and anions for pure ILs. The electron density of H-bonding between cation and anion with different anions decreases in the order [OH](-) > [H(2)PO(4)](-) > [HSO(4)](-) > [CF(3)CO(2)](-) > [Cl](-) > [BF(4)](-) > [PF(6)](-). For aqueous ILs, with increasing water content, the aromatic C-H stretching vibration of the imidazolium cation showed systematic blue-shifts. Especially for BmimOH, the nu(C(2))(-H) undergoes a drastic blue-shift by 58 cm(-1), suggesting that the formation of the strong hydrogen bonds O-H...O may greatly weaken the electron density of H-bonding between the cation and anion of ILs.

  8. Impact of nonlocal electron heat transport on the high temperature plasmas of LHD

    International Nuclear Information System (INIS)

    Tamura, N.; Inagaki, S.; Tokuzawa, T.

    2006-10-01

    Edge cooling experiments with a tracer-encapsulated solid pellet in the Large Helical Device (LHD) show a significant rise of core electron temperature (the maximum rise is around 1 keV) as well as in many tokamaks. This experimental result indicates the possible presence of the nonlocality of electron heat transport in plasmas where turbulence as a cause of anomalous transport is dominated. The nonlocal electron temperature rise in the LHD takes place in almost the same parametric domain (e.g. in a low density) as in the tokamaks. Meanwhile, the experimental results of LHD show some new aspects of nonlocal electron temperature rise, for example the delay of the nonlocal rise of core electron temperature relative to the pellet penetration time increases with the increase in collisionality in the core plasma and the decrease in electron temperature gradient scale length in the outer region of the plasma. (author)

  9. Impact of nonlocal electron heat transport on the high temperature plasmas of LHD

    International Nuclear Information System (INIS)

    Tamura, N.; Inagaki, S.; Tanaka, K.; Michael, C.; Tokuzawa, T.; Shimozuma, T.; Kubo, S.; Sakamoto, R.; Ida, K.; Itoh, K.; Kalinina, D.; Sudo, S.; Nagayama, Y.; Kawahata, K.; Komori, A.

    2007-01-01

    Edge cooling experiments with a tracer-encapsulated solid pellet in the large helical device (LHD) show a significant rise in core electron temperature (the maximum rise is around 1 keV) as well as in many tokamaks. This experimental result indicates the possible presence of the nonlocality of electron heat transport in plasmas where turbulence as a cause of anomalous transport dominates. The nonlocal electron temperature rise in the LHD takes place in almost the same parametric domain (e.g. in a low density) as in the tokamaks. Meanwhile, the experimental results of LHD show some new aspects of nonlocal electron temperature rise, for example the delay in the nonlocal rise of core electron temperature relative to the pellet penetration time increases with the increase both in the collisionality in the core plasma and the electron temperature gradient scale length in the outer region of the plasma

  10. Non-equilibrium thermionic electron emission for metals at high temperatures

    Science.gov (United States)

    Domenech-Garret, J. L.; Tierno, S. P.; Conde, L.

    2015-08-01

    Stationary thermionic electron emission currents from heated metals are compared against an analytical expression derived using a non-equilibrium quantum kappa energy distribution for the electrons. The latter depends on the temperature decreasing parameter κ ( T ) , which decreases with increasing temperature and can be estimated from raw experimental data and characterizes the departure of the electron energy spectrum from equilibrium Fermi-Dirac statistics. The calculations accurately predict the measured thermionic emission currents for both high and moderate temperature ranges. The Richardson-Dushman law governs electron emission for large values of kappa or equivalently, moderate metal temperatures. The high energy tail in the electron energy distribution function that develops at higher temperatures or lower kappa values increases the emission currents well over the predictions of the classical expression. This also permits the quantitative estimation of the departure of the metal electrons from the equilibrium Fermi-Dirac statistics.

  11. Ionic liquids as electrolytes for non-aqueous solutions electrochemical supercapacitors in a temperature range of 20 °C-80 °C

    Science.gov (United States)

    Zhang, Lei; Tsay, Ken; Bock, Christina; Zhang, Jiujun

    2016-08-01

    To increase the operating temperature of the supercapacitors (SCs) without compromising their high cycle-life, several typical fluoro- and non-fluoro containing ionic liquids (EMI-mesylate, EMI-hydrogen sulfate, PP13-triflate, PP13-TFSI, and EMI-TFSI, as shown in Fig. 1) are studied as the electrolytes to prepare organic solutions for SC performance measurements using a two-electrode cell. Both cyclic voltammograms and charge/discharge curves at various temperatures such as 20, 40, 60 and 80 °C are collected. At 60 °C, the increased performance order in both rating and cyclability measurements are found to be as follows: 1) EMI-hydrogen sulfate < PP13-TFSI < EMI-mesylate < PP13-triflate < EMI-TFSI for rating; and 2) EMI-hydrogen sulfate < EMI-mesylate < PP13-Triflate < PP13-TFSI < EMI-TFSI for life-time. The fluoro-containing group of ILs, i.e., PP13-Triflate, PP13-TFSI and EMI-TFSI can give a specific capacitance between 100 and 170 F/g for various scan rates for a conventional carbon electrode, and an extended lifetime test of 10, 000 cycles with a capacitance degradation of less than 10%, indicating that these two ion liquids can be used for SC electrolytes operated at high temperature.

  12. Micelle formation of nonionic surfactants in a room temperature ionic liquid, 1-butyl-3-methylimidazolium tetrafluoroborate: surfactant chain length dependence of the critical micelle concentration.

    Science.gov (United States)

    Inoue, Tohru; Yamakawa, Haruka

    2011-04-15

    Micellization behavior was investigated for polyoxyethylene-type nonionic surfactants with varying chain length (C(n)E(m)) in a room temperature ionic liquid, 1-butyl-3-methylimidazolium tetrafluoroborate (bmimBF(4)). Critical micelle concentration (cmc) was determined from the variation of (1)H NMR chemical shift with the surfactant concentration. The logarithmic value of cmc decreased linearly with the number of carbon atoms in the surfactant hydrocarbon chain, similarly to the case observed in aqueous surfactant solutions. However, the slope of the straight line is much smaller in bmimBF(4) than in aqueous solution. Thermodynamic parameters for micelle formation estimated from the temperature dependence of cmc showed that the micellization in bmimBF(4) is an entropy-driven process around room temperature. This behavior is also similar to the case in aqueous solution. However, the magnitude of the entropic contribution to the overall micellization free energy in bmimBF(4) is much smaller compared with that in aqueous solution. These results suggest that the micellization in bmimBF(4) proceeds through a mechanism similar to the hydrophobic interaction in aqueous surfactant solutions, although the solvophobic effect in bmimBF(4) is much weaker than the hydrophobic effect. Copyright © 2011 Elsevier Inc. All rights reserved.

  13. Electron temperatures within magnetic clouds between 2 and 4 AU: Voyager 2 observations

    Science.gov (United States)

    Sittler, E. C.; Burlaga, L. F.

    1998-08-01

    We have performed an analysis of Voyager 2 plasma electron observations within magnetic clouds between 2 and 4 AU identified by Burlaga and Behannon [1982]. The analysis has been confined to three of the magnetic clouds identified by Burlaga and Behannon that had high-quality data. The general properties of the plasma electrons within a magnetic cloud are that (1) the moment electron temperature anticorrelates with the electron density within the cloud, (2) the ratio Te/Tp tends to be >1, and (3) on average, Te/Tp~7.0. All three results are consistent with previous electron observations within magnetic clouds. Detailed analyses of the core and halo populations within the magnetic clouds show no evidence of either an anticorrelation between the core temperature TC and the electron density Ne or an anticorrelation between the halo temperature TH and the electron density. Within the magnetic clouds the halo component can contribute more than 50% of the electron pressure. The anticorrelation of Te relative to Ne can be traced to the density of the halo component relative to the density of the core component. The core electrons dominate the electron density. When the density goes up, the halo electrons contribute less to the electron pressure, so we get a lower Te. When the electron density goes down, the halo electrons contribute more to the electron pressure, and Te goes up. We find a relation between the electron pressure and density of the form Pe=αNeγ with γ~0.5.

  14. Effect of two-temperature electrons distribution on an electrostatic plasma sheath

    International Nuclear Information System (INIS)

    Ou, Jing; Xiang, Nong; Gan, Chunyun; Yang, Jinhong

    2013-01-01

    A magnetized collisionless plasma sheath containing two-temperature electrons is studied using a one-dimensional model in which the low-temperature electrons are described by Maxwellian distribution (MD) and high-temperature electrons are described by truncated Maxwellian distribution (TMD). Based on the ion wave approach, a modified sheath criterion including effect of TMD caused by high-temperature electrons energy above the sheath potential energy is established theoretically. The model is also used to investigate numerically the sheath structure and energy flux to the wall for plasmas parameters of an open divertor tokamak-like. Our results show that the profiles of the sheath potential, two-temperature electrons and ions densities, high-temperature electrons and ions velocities as well as the energy flux to the wall depend on the high-temperature electrons concentration, temperature, and velocity distribution function associated with sheath potential. In addition, the results obtained in the high-temperature electrons with TMD as well as with MD sheaths are compared for the different sheath potential

  15. Space Charge Saturated Sheath Regime and Electron Temperature Saturation in Hall Thrusters

    International Nuclear Information System (INIS)

    Raitses, Y.; Staack, D.; Smirnov, A.; Fisch, N.J.

    2005-01-01

    Secondary electron emission in Hall thrusters is predicted to lead to space charge saturated wall sheaths resulting in enhanced power losses in the thruster channel. Analysis of experimentally obtained electron-wall collision frequency suggests that the electron temperature saturation, which occurs at high discharge voltages, appears to be caused by a decrease of the Joule heating rather than by the enhancement of the electron energy loss at the walls due to a strong secondary electron emission

  16. Saturation mechanism of decaying ion temperature gradient driven turbulence with kinetic electrons

    International Nuclear Information System (INIS)

    Idomura, Yasuhiro

    2016-01-01

    We present full-f gyrokinetic simulations of the ion temperature gradient driven (ITG) turbulence including kinetic electrons. By comparing decaying ITG turbulence simulations with adiabatic and kinetic electron models, an impact of kinetic electrons on the ITG turbulence is investigated. It is found that significant electron transport occurs even in the ITG turbulence, and both ion and electron temperature profiles are relaxed. In steady states, both cases show upshifts of nonlinear critical ion temperature gradients from linear ones, while their saturation mechanisms are qualitatively different. In the adiabatic electron case, the ITG mode is stabilized by turbulence driven zonal flows. On the other hand, in the kinetic electron case, passing electrons transport shows fine resonant structures at mode rational surfaces, which generate corrugated density profiles. Such corrugated density profiles lead to fine radial electric fields following the neoclassical force balance relation. The resulting E × B shearing rate greatly exceeds the linear growth rate of the ITG mode. (author)

  17. Revisiting the definition of the electronic chemical potential, chemical hardness, and softness at finite temperatures

    International Nuclear Information System (INIS)

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

    2015-01-01

    We extend the definition of the electronic chemical potential (μ e ) and chemical hardness (η e ) to finite temperatures by considering a reactive chemical species as a true open system to the exchange of electrons, working exclusively within the framework of the grand canonical ensemble. As in the zero temperature derivation of these descriptors, the response of a chemical reagent to electron-transfer is determined by the response of the (average) electronic energy of the system, and not by intrinsic thermodynamic properties like the chemical potential of the electron-reservoir which is, in general, different from the electronic chemical potential, μ e . Although the dependence of the electronic energy on electron number qualitatively resembles the piecewise-continuous straight-line profile for low electronic temperatures (up to ca. 5000 K), the introduction of the temperature as a free variable smoothens this profile, so that derivatives (of all orders) of the average electronic energy with respect to the average electron number exist and can be evaluated analytically. Assuming a three-state ensemble, well-known results for the electronic chemical potential at negative (−I), positive (−A), and zero values of the fractional charge (−(I + A)/2) are recovered. Similarly, in the zero temperature limit, the chemical hardness is formally expressed as a Dirac delta function in the particle number and satisfies the well-known reciprocity relation with the global softness

  18. Revisiting the definition of the electronic chemical potential, chemical hardness, and softness at finite temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Franco-Pérez, Marco, E-mail: qimfranco@hotmail.com, E-mail: jlgm@xanum.uam.mx [Departamento de Química, Universidad Autónoma Metropolitana-Iztapalapa, Av. San Rafael Atlixco 186, México D. F. 09340 (Mexico); Department of Chemistry, McMaster University, Hamilton, Ontario L8S 4M1 (Canada); Gázquez, José L., E-mail: qimfranco@hotmail.com, E-mail: jlgm@xanum.uam.mx [Departamento de Química, Universidad Autónoma Metropolitana-Iztapalapa, Av. San Rafael Atlixco 186, México D. F. 09340 (Mexico); Ayers, Paul W. [Department of Chemistry, McMaster University, Hamilton, Ontario L8S 4M1 (Canada); Vela, Alberto [Departamento de Química, Centro de Investigación y de Estudios Avanzados (Cinvestav), Av. Instituto Politécnico Nacional 2508, México D. F. 07360 (Mexico)

    2015-10-21

    We extend the definition of the electronic chemical potential (μ{sub e}) and chemical hardness (η{sub e}) to finite temperatures by considering a reactive chemical species as a true open system to the exchange of electrons, working exclusively within the framework of the grand canonical ensemble. As in the zero temperature derivation of these descriptors, the response of a chemical reagent to electron-transfer is determined by the response of the (average) electronic energy of the system, and not by intrinsic thermodynamic properties like the chemical potential of the electron-reservoir which is, in general, different from the electronic chemical potential, μ{sub e}. Although the dependence of the electronic energy on electron number qualitatively resembles the piecewise-continuous straight-line profile for low electronic temperatures (up to ca. 5000 K), the introduction of the temperature as a free variable smoothens this profile, so that derivatives (of all orders) of the average electronic energy with respect to the average electron number exist and can be evaluated analytically. Assuming a three-state ensemble, well-known results for the electronic chemical potential at negative (−I), positive (−A), and zero values of the fractional charge (−(I + A)/2) are recovered. Similarly, in the zero temperature limit, the chemical hardness is formally expressed as a Dirac delta function in the particle number and satisfies the well-known reciprocity relation with the global softness.

  19. The kinetics of low-temperature electron-phonon relaxation in a metallic film following instantaneous heating of the electrons

    International Nuclear Information System (INIS)

    Bezuglyi, A.I.; Shklovskii, V.A.

    1997-01-01

    The theoretical analysis of experiments on pulsed laser irradiation of metallic films sputtered on insulating supports is usually based on semiphenomenological dynamical equations for the electron and phonon temperatures, an approach that ignores the nonuniformity and the nonthermal nature of the phonon distribution function. In this paper we discuss a microscopic model that describes the dynamics of the electron-phonon system in terms of kinetic equations for the electron and phonon distribution functions. Such a model provides a microscopic picture of the nonlinear energy relaxation of the electron-phonon system of a rapidly heated film. We find that in a relatively thick film the energy relaxation of electrons consists of three stages: the emission of nonequilibrium phonons by 'hot' electrons, the thermalization of electrons and phonons due to phonon reabsorption, and finally the cooling of the thermalized electron-phonon system as a result of phonon exchange between film and substrate. In thin films, where there is no reabsorption of nonequilibrium phonons, the energy relaxation consists of only one stage, the first. The relaxation dynamics of an experimentally observable quantity, the phonon contribution to the electrical conductivity of the cooling film, is directly related to the dynamics of the electron temperature, which makes it possible to use the data of experiments on the relaxation of voltage across films to establish the electron-phonon and phonon-electron collision times and the average time of phonon escape from film to substrate

  20. Positronium formation at low temperatures: The role of trapped electrons

    DEFF Research Database (Denmark)

    Hirade, T.; Maurer, F.H.J.; Eldrup, Morten Mostgaard

    2000-01-01

    Measurements have been carried out of electron spin densities (by electron spin resonance technique) and positronium (Ps) formation probability as functions of Co-60 gamma-irradiation dose in poly(methyl methacrylate) and linear poly(ethylene) at 77 K. We observe a linear relationship between...

  1. Application of Ionic Liquids in Hydrometallurgy

    Science.gov (United States)

    Park, Jesik; Jung, Yeojin; Kusumah, Priyandi; Lee, Jinyoung; Kwon, Kyungjung; Lee, Churl Kyoung

    2014-01-01

    Ionic liquids, low temperature molten salts, have various advantages manifesting themselves as durable and environmentally friendly solvents. Their application is expanding into various fields including hydrometallurgy due to their unique properties such as non-volatility, inflammability, low toxicity, good ionic conductivity, and wide electrochemical potential window. This paper reviews previous literatures and our recent results adopting ionic liquids in extraction, synthesis and processing of metals with an emphasis on the electrolysis of active/light, rare earth, and platinum group metals. Because the research and development of ionic liquids in this area are still emerging, various, more fundamental approaches are expected to popularize ionic liquids in the metal manufacturing industry. PMID:25177864

  2. Determination of equilibrium electron temperature and times using an electron swarm model with BOLSIG+ calculated collision frequencies and rate coefficients

    International Nuclear Information System (INIS)

    Pusateri, Elise N.; Morris, Heidi E.; Nelson, Eric M.; Ji, Wei

    2015-01-01

    Electromagnetic pulse (EMP) events produce low-energy conduction electrons from Compton electron or photoelectron ionizations with air. It is important to understand how conduction electrons interact with air in order to accurately predict EMP evolution and propagation. An electron swarm model can be used to monitor the time evolution of conduction electrons in an environment characterized by electric field and pressure. Here a swarm model is developed that is based on the coupled ordinary differential equations (ODEs) described by Higgins et al. (1973), hereinafter HLO. The ODEs characterize the swarm electric field, electron temperature, electron number density, and drift velocity. Important swarm parameters, the momentum transfer collision frequency, energy transfer collision frequency, and ionization rate, are calculated and compared to the previously reported fitted functions given in HLO. These swarm parameters are found using BOLSIG+, a two term Boltzmann solver developed by Hagelaar and Pitchford (2005), which utilizes updated cross sections from the LXcat website created by Pancheshnyi et al. (2012). We validate the swarm model by comparing to experimental effective ionization coefficient data in Dutton (1975) and drift velocity data in Ruiz-Vargas et al. (2010). In addition, we report on electron equilibrium temperatures and times for a uniform electric field of 1 StatV/cm for atmospheric heights from 0 to 40 km. We show that the equilibrium temperature and time are sensitive to the modifications in the collision frequencies and ionization rate based on the updated electron interaction cross sections

  3. Selective determination of inorganic cobalt in nutritional supplements by ultrasound-assisted temperature-controlled ionic liquid dispersive liquid phase microextraction and electrothermal atomic absorption spectrometry

    International Nuclear Information System (INIS)

    Berton, Paula; Martinis, Estefanía M.; Martinez, Luis D.; Wuilloud, Rodolfo G.

    2012-01-01

    Highlights: ► Synergy of ultrasound energy and TILDLME technique for improved metal extraction. ► Highly selective determination of inorganic Co species at trace levels. ► Speciation analysis of Co in several nutritional supplements with highly complex matrices. ► Development of an environmentally friendly microextraction technique with minimal waste production and sample consumption. - Abstract: In the present work, a simple and rapid analytical method based on application of ionic liquids (ILs) for inorganic Co(II) species (iCo) microextraction in a variety of nutrient supplements was developed. Inorganic Co was initially chelated with 1-nitroso-2-naphtol (1N2N) reagent followed by a modern technique named ultrasound-assisted temperature-controlled ionic liquid dispersive liquid phase microextraction (USA-TILDLME). The extraction was performed with 1-hexyl-3-methylimidazolium hexafluorophosphate [C 6 mim][PF 6 ] with the aid of ultrasound to improve iCo recovery. Finally, the iCo-enriched IL phase was solubilized in methanol and directly injected into an electrothermal atomic absorption spectrometer (ETAAS). Several parameters that could influence iCo microextraction and detection were carefully studied. Since the main difficulty in these samples is caused by high concentrations of potential interfering ions, different approaches were evaluated to eliminate interferences. The limit of detection (LOD) was 5.4 ng L −1 , while the relative standard deviation (RSD) was 4.7% (at 0.5 μg L −1 Co level and n = 10), calculated from the peak height of absorbance signals. Selective microextraction of iCo species was achieved only by controlling the pH value during the procedure. The method was thus successfully applied for determination of iCo species in nutritional supplements.

  4. Selective determination of inorganic cobalt in nutritional supplements by ultrasound-assisted temperature-controlled ionic liquid dispersive liquid phase microextraction and electrothermal atomic absorption spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Berton, Paula; Martinis, Estefania M. [Analytical Chemistry Research and Development Group (QUIANID), (LISAMEN-CCT-CONICET-Mendoza), Av. Ruiz Leal S/N Parque General San Martin, M 5502 IRA Mendoza (Argentina); Martinez, Luis D. [INQUISAL-CONICET, Departamento de Quimica Analitica, Facultad de Quimica, Bioquimica y Farmacia, Universidad Nacional de San Luis, San Luis (Argentina); Wuilloud, Rodolfo G., E-mail: rwuilloud@mendoza-conicet.gob.ar [Analytical Chemistry Research and Development Group (QUIANID), (LISAMEN-CCT-CONICET-Mendoza), Av. Ruiz Leal S/N Parque General San Martin, M 5502 IRA Mendoza (Argentina); Instituto de Ciencias Basicas, Universidad Nacional de Cuyo, Mendoza (Argentina)

    2012-02-03

    Highlights: Black-Right-Pointing-Pointer Synergy of ultrasound energy and TILDLME technique for improved metal extraction. Black-Right-Pointing-Pointer Highly selective determination of inorganic Co species at trace levels. Black-Right-Pointing-Pointer Speciation analysis of Co in several nutritional supplements with highly complex matrices. Black-Right-Pointing-Pointer Development of an environmentally friendly microextraction technique with minimal waste production and sample consumption. - Abstract: In the present work, a simple and rapid analytical method based on application of ionic liquids (ILs) for inorganic Co(II) species (iCo) microextraction in a variety of nutrient supplements was developed. Inorganic Co was initially chelated with 1-nitroso-2-naphtol (1N2N) reagent followed by a modern technique named ultrasound-assisted temperature-controlled ionic liquid dispersive liquid phase microextraction (USA-TILDLME). The extraction was performed with 1-hexyl-3-methylimidazolium hexafluorophosphate [C{sub 6}mim][PF{sub 6}] with the aid of ultrasound to improve iCo recovery. Finally, the iCo-enriched IL phase was solubilized in methanol and directly injected into an electrothermal atomic absorption spectrometer (ETAAS). Several parameters that could influence iCo microextraction and detection were carefully studied. Since the main difficulty in these samples is caused by high concentrations of potential interfering ions, different approaches were evaluated to eliminate interferences. The limit of detection (LOD) was 5.4 ng L{sup -1}, while the relative standard deviation (RSD) was 4.7% (at 0.5 {mu}g L{sup -1} Co level and n = 10), calculated from the peak height of absorbance signals. Selective microextraction of iCo species was achieved only by controlling the pH value during the procedure. The method was thus successfully applied for determination of iCo species in nutritional supplements.

  5. High-Performance Supercapacitor of Functionalized Carbon Fiber Paper with High Surface Ionic and Bulk Electronic Conductivity: Effect of Organic Functional Groups

    International Nuclear Information System (INIS)

    Suktha, Phansiri; Chiochan, Poramane; Iamprasertkun, Pawin; Wutthiprom, Juthaporn; Phattharasupakun, Nutthaphon; Suksomboon, Montakan; Kaewsongpol, Tanon; Sirisinudomkit, Pichamon; Pettong, Tanut; Sawangphruk, Montree

    2015-01-01

    Highlights: • A supercapacitor of organic functionalized carbon fiber paper (f-CFP) exhibits high areal and volumetric capacitances. • The performance of the supercapacitor depends on the organic functional group on the surface of the f-CFP. • Hydroxyl and carboxylic groups modified on the surface of f-CFP have higher pseudocapacitive property than amide and amine functional groups. • The f-CFP exhibits high surface ionic and bulk electrical conductivities. - Abstract: Although carbon fiber paper (CFP) or nonwovens are widely used as a non-corrosive and conductive substrate or current collector in batteries and supercapacitors as well as a gas diffusion layer in proton exchange membrane fuel cells, the CFP cannot store charges due to its poor ionic conductivity and its hydrophobic surface. In this work, the chemically functionalized CFP (f-CFP) consisting of hydroxyl and carboxylic groups on its surface was produced by an oxidation reaction of CFP in a mixed concentrated acid solution of H 2 SO 4 :HNO 3 (3:1 v/v) at 60 °C for 1 h. Other amide and amine groups modified CFP were also synthesized for comparison using a dehydration reaction of carboxylic modified CFP with ethylenediamine and n-butylamine. Interestingly, it was found that hydroxyl and carboxylic groups modified CFP behave as a pseudocapacitor electrode, which can store charges via the surface redox reaction in addition to electrochemical double layer capacitance. The aqueous-based supercapacitor of f-CFP has high areal, volumetric, and specific energy (49.0 μW.h/cm 2 , 1960 mW.h/L, and 5.2 W.h/Kg) and power (3.0 mW/cm 2 , 120 W/L, and 326.2 W/Kg) based on the total geometrical surface area and volume as well as the total weight of positive and negative electrodes. High charge capacity of the f-CFP stems from high ionic charge and pseudocapacitive behavior due to hydroxyl and carboxylic groups on its surface and high bulk electronic conductivity (2.03 mS/cm) due to 1D carbon fiber paper. The

  6. Effective temperature of an ultracold electron source based on near-threshold photoionization

    NARCIS (Netherlands)

    Engelen, W.J.; Smakman, E.P.; Bakker, D.J.; Luiten, O.J.; Vredenbregt, E.J.D.

    2014-01-01

    We present a detailed description of measurements of the effective temperature of a pulsed electron source, based on near-threshold photoionization of laser-cooled atoms. The temperature is determined by electron beam waist scans, source size measurements with ion beams, and analysis with an

  7. Room temperature Compton profiles of conduction electrons in α-Ga ...

    Indian Academy of Sciences (India)

    Room temperature Compton profiles of momentum distribution of conduction electrons in -Ga metal are calculated in band model. For this purpose, the conduction electron wave functions are determined in a temperature-dependent non-local model potential. The profiles calculated along the crystallographic directions, ...

  8. High-Temperature Electronics: Status and Future Prospects in the 21st Century

    Directory of Open Access Journals (Sweden)

    F. Touati

    2006-12-01

    Full Text Available This paper reviews the state of current electronics and states the drive toward high-temperature electronics. The problems specific to high-temperature effects on conventional electronics and prospects of alternative technologies like silicon-on-insulator, silicon carbide, and diamond are discussed. Improving petroleum recovery from oil wells with hightemperature coverage of downhole electronics, making combustion processes more efficient utilizing embedded electronics, programs for More Electric Aircraft and Vehicles necessitating distributed control systems, and environmental protection issues stress the need to use and develop high-temperature electronics. This makes high-temperature electronics a key-enabling technology in the 21st century. Actual applications using high-temperature electronics are discussed in some details. Also information and guidelines are included about supporting electronics needed to make a complete high-temperature system. The technology has been making major advancements and is expected to account for 20% of the electronics market by 2010. However, many technical challenges have to be solved.

  9. Electrochemical studies of UO22+ in 1-octyl 3- methylimidazolium hexafluorophosphate (omimPF6) room temperature ionic liquid

    International Nuclear Information System (INIS)

    Kamat, J.V.; Gopinath, N.; Lohithakshan, K.V.; Aggarwal, S.K.

    2007-01-01

    The effect of the degraded products on the Electrochemical Window (EW) of l-octyl 3- methylimidazolium hexafluorophosphate (OmimPF 6 ) were studied. Studies were also carried to optimize conditions for extraction of UO 2 2+ to investigate its redox behavior in OmimPF6 and determine the number of electrons involved in the redox chemistry. The Chronoamperometric technique of evaluating n without knowing diffusion coefficient, D, was devised by Kakihana et al. and has been applied in the present work. The number of electrons involved was determined from the values of slope and intercept of the Cottrell plot. The results of these studies are presented in this paper

  10. Electron-dislocation interaction at low temperatures. Progress report

    International Nuclear Information System (INIS)

    1976-01-01

    Studies of the interaction of mobile dislocations with electrons have shown that dislocation motion can be, in part, described by treating the dislocation as an underdamped oscillator. In particular, studies in lead alloys have shown tht dislocation motion can be considered as the motion of string, slightly damped by electrons, without regard for any other lattice friction. In addition we have shown that silver solutes, in lead crystals, occupy, partially, interstitial sites. Finally, we have shown that dislocations in copper interact, unexpectedly, with electrons. This is shown by measuring the influence of a magnetic field on the flow stress of copper crystals at 4.2 0 K

  11. Measurement of peripheral electron temperature by electron cyclotron emission during the H-mode transition in JFT-2M tokamak

    International Nuclear Information System (INIS)

    Hoshino, Katsumichi; Yamamoto, Takumi; Kawashima, Hisato

    1987-01-01

    Time evolution and profile of peripheral electron temperature during the H-mode like transition in a tokamak plasma is measured using the second and third harmonic of electron cyclotron emission (ECE). The so called ''H-mode'' state which has good particle/energy confinement is characterized by sudden decrease in the spectral line intensity of deuterium molecule. Such a sudden decrease in the line intensity of D α with good energy confinement is found not only in divertor discharges, but also in limiter dischargs in JFT-2M tokamak. It is found by the measurement of ECE that the peripheral electron temperature suddenly increases in both of such phases. The relation between H-transition and the peripheral electron temperature or its profile is investigated. (author)

  12. Effect of electron temperature on small-amplitude electron acoustic solitary waves in non-planar geometry

    Science.gov (United States)

    Bansal, Sona; Aggarwal, Munish; Gill, Tarsem Singh

    2018-04-01

    Effects of electron temperature on the propagation of electron acoustic solitary waves in plasma with stationary ions, cold and superthermal hot electrons is investigated in non-planar geometry employing reductive perturbation method. Modified Korteweg-de Vries equation is derived in the small amplitude approximation limit. The analytical and numerical calculations of the KdV equation reveal that the phase velocity of the electron acoustic waves increases as one goes from planar to non planar geometry. It is shown that the electron temperature ratio changes the width and amplitude of the solitary waves and when electron temperature is not taken into account,our results completely agree with the results of Javidan & Pakzad (2012). It is found that at small values of τ , solitary wave structures behave differently in cylindrical ( {m} = 1), spherical ( {m} = 2) and planar geometry ( {m} = 0) but looks similar at large values of τ . These results may be useful to understand the solitary wave characteristics in laboratory and space environments where the plasma have multiple temperature electrons.

  13. SSVD Extreme Temperature Electronics for Planned Venus Missions, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — The purpose of this project is to demonstrate, based on a new class of electronic devices called solid state vacuum devices (SSVD?s), a highly promising enabling...

  14. Physically Gelled Room-Temperature Ionic Liquid-Based Composite Membranes for CO2/N-2 Separation: Effect of Composition and Thickness on Membrane Properties and Performance

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen, PT; Voss, BA; Wiesenauer, EF; Gin, DL; Nobe, RD

    2013-07-03

    An aspartame-based, low molecular-weight organic gelator (LMOG) was used to form melt-infused and composite membranes with two different imidazolium-based room-temperature ionic liquids (RTILs) for CO2 separation from N-2. Previous work demonstrated that LMOGs can gel RTILs at low, loading levels, and this aspartame-based LMOG was selected because it has been reported to gel a large number of RTILs. The imidazolium-based RTILs were used because of their inherent good properties for CO2/light gas separations. Analysis of the resulting bulk RTIL/LMOG physical gels showed that these materials have high sol-gel transition temperatures (ca. 135 degrees C) suitable for flue gas applications. Gas permeabilities and burst pressure measurements of thick, melt infused membranes revealed a trade-off between high CO2 permeabilities and good mechanical stability as a function of the LMOG loading. Defect-free, composite membranes of the gelled RTILs were successfully fabricated by choosing an appropriate porous membrane support (hydrophobic PTFE) using a suitable coating technique (roller coating). The thicknesses of the applied composite gel layers ranged from 10.3 to 20.7 mu m, which represents an order of magnitude decrease in active layer thickness, compared to the original melt-infused gel RTIL membranes.

  15. High temperature, radiation hardened electronics for application to nuclear power plants

    International Nuclear Information System (INIS)

    Gover, J.E.

    1980-01-01

    Electronic circuits were developed and built at Sandia for many aerospace and energy systems applications. Among recent developments were high temperature electronics for geothermal well logging and radiation hardened electronics for a variety of aerospace applications. Sandia has also been active in technology transfer to commercial industry in both of these areas

  16. MIXING THE SOLAR WIND PROTON AND ELECTRON SCALES: EFFECTS OF ELECTRON TEMPERATURE ANISOTROPY ON THE OBLIQUE PROTON FIREHOSE INSTABILITY

    Energy Technology Data Exchange (ETDEWEB)

    Maneva, Y.; Lazar, M.; Poedts, S. [Centre for Mathematical Plasma Astrophysics, Celestijnenlaan 200B, 3001 Heverlee (Belgium); Viñas, A., E-mail: yana.maneva@wis.kuleuven.be [NASA Goddard Space Flight Center, Heliophysics Science Division, Greenbelt, MD 20771 (United States)

    2016-11-20

    The double adiabatic expansion of the nearly collisionless solar wind plasma creates conditions for the firehose instability to develop and efficiently prevent the further increase of the plasma temperature in the direction parallel to the interplanetary magnetic field. The conditions imposed by the firehose instability have been extensively studied using idealized approaches that ignore the mutual effects of electrons and protons. Recently, more realistic approaches have been proposed that take into account the interplay between electrons and protons, unveiling new regimes of the parallel oscillatory modes. However, for oblique wave propagation the instability develops distinct branches that grow much faster and may therefore be more efficient than the parallel firehose instability in constraining the temperature anisotropy of the plasma particles. This paper reports for the first time on the effects of electron plasma properties on the oblique proton firehose (PFH) instability and provides a comprehensive vision of the entire unstable wave-vector spectrum, unifying the proton and the smaller electron scales. The plasma β and temperature anisotropy regimes considered here are specific for the solar wind and magnetospheric conditions, and enable the electrons and protons to interact via the excited electromagnetic fluctuations. For the selected parameters, simultaneous electron and PFH instabilities can be observed with a dispersion spectrum of the electron firehose (EFH) extending toward the proton scales. Growth rates of the PFH instability are markedly boosted by the anisotropic electrons, especially in the oblique direction where the EFH growth rates are orders of magnitude higher.

  17. Mixing the Solar Wind Proton and Electron Scales: Effects of Electron Temperature Anisotropy on the Oblique Proton Firehose Instability

    Science.gov (United States)

    Maneva, Y.; Lazar, M.; Vinas, A.; Poedts, S.

    2016-01-01

    The double adiabatic expansion of the nearly collisionless solar wind plasma creates conditions for the firehose instability to develop and efficiently prevent the further increase of the plasma temperature in the direction parallel to the interplanetary magnetic field. The conditions imposed by the firehose instability have been extensively studied using idealized approaches that ignore the mutual effects of electrons and protons. Recently, more realistic approaches have been proposed that take into account the interplay between electrons and protons,? unveiling new regimes of the parallel oscillatory modes. However, for oblique wave propagation the instability develops distinct branches that grow much faster and may therefore be more efficient than the parallel firehose instability in constraining the temperature anisotropy of the plasma particles. This paper reports for the first time on the effects of electron plasma properties on the oblique proton firehose (PFH) instability and provides a comprehensive vision of the entire unstable wave-vector spectrum, unifying the proton and the smaller electron scales. The plasma ß and temperature anisotropy regimes considered here are specific for the solar wind and magnetospheric conditions, and enable the electrons and protons to interact via the excited electromagnetic fluctuations. For the selected parameters, simultaneous electron and PFH instabilities can be observed with a dispersion spectrum of the electron firehose (EFH) extending toward the proton scales. Growth rates of the PFH instability are markedly boosted by the anisotropic electrons, especially in the oblique direction where the EFH growth rates are orders of magnitude higher.

  18. Concentration and electrode material dependence of the voltammetric response of iodide on platinum, glassy carbon and boron-doped diamond in the room temperature ionic liquid 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide

    International Nuclear Information System (INIS)

    Bentley, Cameron L.; Bond, Alan M.; Hollenkamp, Anthony F.; Mahon, Peter J.; Zhang, Jie

    2013-01-01

    The electro-oxidation of iodide has been investigated as a function of concentration using steady-state microelectrode voltammetry, transient cyclic voltammetry and linear-sweep semi-integral voltammetry on platinum, glassy carbon and boron-doped diamond electrodes in the room temperature ionic liquid 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide. Two oxidation processes are observed on all of the investigated electrode materials, with the first being assigned to the oxidation of iodide to triiodide (confirmed by UV/visible spectroscopy) and the second being attributed to the oxidation of triiodide to iodine. Iodide oxidation is kinetically more facile on platinum compared to glassy carbon or boron-doped diamond. At elevated bulk iodide concentrations, the nucleation and growth of sparingly soluble electrogenerated iodine at the electrode surface was observed and imaged in situ using optical microscopy. The diffusion coefficient of iodide was determined to be 2.59 (±0.04) × 10 −7 cm 2 s −1 and independent of the bulk concentration of iodide. The steady-state iodide oxidation current measured at a platinum microelectrode was found to be a linear function of iodide concentration, as expected if there are no contributions from non-Stokesian mass-transport processes (electron hopping and/or Grotthuss-type exchange) under the investigated conditions

  19. Studies in solid state ionics

    International Nuclear Information System (INIS)

    Jakes, D.; Rosenkranz, J.

    1987-01-01

    Studies performed over 10 years by the high temperature chemistry group are reviewed. Attention was paid to different aspects of ionic solids from the point of view of practical as well as theoretical needs of nuclear technology. Thus ceramic fuel compound like uranates, urania-thoria system, solid electrolytes based on oxides and ionics transformations were studied under reactor irradiation. (author) 13 figs., 3 tabs., 46 refs

  20. An efficient ultrasound assisted approach for the impregnation of room temperature ionic liquid onto Dowex 1 × 8 resin matrix and its application toward the enhanced adsorption of chromium (VI)

    International Nuclear Information System (INIS)

    Kalidhasan, S.; Santhana Krishna Kumar, A.; Vidya Rajesh; Rajesh, N.

    2012-01-01

    Highlights: ► Ultrasound assisted impregnation of an ionic liquid in a Dowex resin matrix is studied through various physicochemical and spectroscopic techniques. ► Chromium is adsorbed with a high adsorption capacity of 230.9 mg g −1 . ► The adsorbent is regenerated using HCl–ascorbic acid mixture. ► Chromium could be effectively detoxified from an industrial effluent and the developed method was validated with the analysis of a certified reference material. - Abstract: The work discussed in this paper is based on the utilization of ultrasound in conjunction with an ionic liquid (Aliquat 336) impregnated Dowex 1 × 8 resin for the effective adsorption of chromium. Ionic liquids are known for their selectivity toward metal extraction and ultrasonic medium offers efficient energy transfer for impregnating the ionic liquid in the resin matrix. The molecular interaction between the ionic liquid impregnated resin and chromium was studied through various physicochemical and spectroscopic techniques. The influence of various analytical parameters on the adsorption of Cr(VI) such as pH, adsorbent dosage, temperature and interference of foreign ions was studied in detail. Chromium (VI) was quantitatively adsorbed in the pH range of 3.5–4, with a high adsorption capacity of 230.9 mg g −1 in conformity with the Langmuir isotherm model. The study of thermodynamic parameters showed that the adsorption process is exothermic and spontaneous. The adsorbent could be regenerated using 1 mol L −1 HCl–0.28 mol L −1 ascorbic acid mixture. Chromium could be effectively detoxified from an industrial effluent and finally the developed method was validated with the analysis of a certified reference material (BCR-715). The obtained results indicated that the ultrasonic assisted impregnation of the room temperature ionic liquid significantly enhances and improves the removal efficiency of Cr(VI).

  1. Room Temperature Deposition Processes Mediated By Ultrafast Photo-Excited Hot Electrons

    Science.gov (United States)

    2014-01-30

    mechanical through resonant energy transfer. The average electron temperature (Tel) during τ2 evolves as energy is lost through optical and acoustic ...through ballistic collisions and acoustic phonons. The large difference in heat capacities between electrons and the substrate leads to negligible...temperature pyrometer indicated only a ~30oC temperature gradient between the thermocouple location and the topside of the sample which faced the

  2. Effect of temperature and ionic impurities at very low concentrations on stress corrosion cracking of type 304 stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Ruther, W.E.; Soppet, W.K.; Kassner, T.F.

    1984-11-01

    The relative effect of approx. 12 anion species, in conjunction with hydrogen and sodium cations, on the stress-corrosion-cracking (SCC) behavior of lightly sensitized Type 304 stainless steel was investigated in constant-extension-rate-tensile (CERT) tests at 289/sup 0/C in water with 0.2 ppM dissolved oxygen at total conductivity values of less than or equal to 1 ..mu..S/cm. The results show that the sulfur species, either in acid or sodium form, produce the highest degree of IGSCC relative to other anions. The effect of temperature on the SCC behavior of the material was investigated in CERT tests over the range 110 to 320/sup 0/C in high-purity water and in water containing 0.1 and 1.0 ppM sulfate as H/sub 2/SO/sub 4/ at a dissolved oxygen concentration of 0.2 ppM. The CERT parameters were correlated with impurity concentration (i.e., conductivity) and the electrochemical potential of platinum and Type 304 stainless steel electrodes in the high-temperature environments. Maximum IGSCC occurred at temperatures between approx. 200 and 250/sup 0/C in high-purity water, and the addition of sulfate increased the average crack growth rates and the temperature range over which maximum susceptibility occurred. A distinct transition from intergranular to transgranular and ultimately to a ductile failure mode was observed as the temperature increased from approx. 270 to 320/sup 0/C in high-purity water. This transition was attributed to a decrease in the open-circuit corrosion potential of the steel below a critical value of approx. 0 mV(SHE) at the higher temperature. A large decrease in the crack growth rates of fracture-mechanics-type specimens of the steel was also found when the temperature was increased from 289 to 320/sup 0/C in high-purity water with 0.2 ppM dissolved oxygen. 26 references, 8 figures, 6 tables.

  3. Effect of temperature and ionic impurities at very low concentrations on stress corrosion cracking of type 304 stainless steel

    International Nuclear Information System (INIS)

    Ruther, W.E.; Soppet, W.K.; Kassner, T.F.

    1984-11-01

    The relative effect of approx. 12 anion species, in conjunction with hydrogen and sodium cations, on the stress-corrosion-cracking (SCC) behavior of lightly sensitized Type 304 stainless steel was investigated in constant-extension-rate-tensile (CERT) tests at 289 0 C in water with 0.2 ppM dissolved oxygen at total conductivity values of less than or equal to 1 μS/cm. The results show that the sulfur species, either in acid or sodium form, produce the highest degree of IGSCC relative to other anions. The effect of temperature on the SCC behavior of the material was investigated in CERT tests over the range 110 to 320 0 C in high-purity water and in water containing 0.1 and 1.0 ppM sulfate as H 2 SO 4 at a dissolved oxygen concentration of 0.2 ppM. The CERT parameters were correlated with impurity concentration (i.e., conductivity) and the electrochemical potential of platinum and Type 304 stainless steel electrodes in the high-temperature environments. Maximum IGSCC occurred at temperatures between approx. 200 and 250 0 C in high-purity water, and the addition of sulfate increased the average crack growth rates and the temperature range over which maximum susceptibility occurred. A distinct transition from intergranular to transgranular and ultimately to a ductile failure mode was observed as the temperature increased from approx. 270 to 320 0 C in high-purity water. This transition was attributed to a decrease in the open-circuit corrosion potential of the steel below a critical value of approx. 0 mV(SHE) at the higher temperature. A large decrease in the crack growth rates of fracture-mechanics-type specimens of the steel was also found when the temperature was increased from 289 to 320 0 C in high-purity water with 0.2 ppM dissolved oxygen. 26 references, 8 figures, 6 tables

  4. Ionic polarization

    International Nuclear Information System (INIS)

    Mahan, G.D.

    1992-01-01

    Ferroelectricity occurs in many different kinds of materials. Many of the technologically important solids, which are ferroelectric, can be classified as ionic. Any microscopic theory of ferroelectricity must contain a description of local polarization forces. We have collaborated in the development of a theory of ionic polarization which is quite successful. Its basic assumption is that the polarization is derived from the properties of the individual ions. We have applied this theory successfully to diverse subjects as linear and nonlinear optical response, phonon dispersion, and piezoelectricity. We have developed numerical methods using the local Density approximation to calculate the multipole polarizabilities of ions when subject to various fields. We have also developed methods of calculating the nonlinear hyperpolarizability, and showed that it can be used to explain light scattering experiments. This paper elaborates on this polarization theory

  5. Study on radiation-induced reaction in microscopic region for basic understanding of electron beam patterning in lithographic process. 2. Relation between resist space resolution and space distribution of ionic species

    International Nuclear Information System (INIS)

    Saeki, Akinori; Kozawa, Takahiro; Yoshida, Yoichi; Tagawa, Seiichi

    2002-01-01

    For basic research on electron beam lithography, the time-dependent distribution was measured. In the case of nano-scale electron beam lithography, the distribution of ionic species is thought to have an influence on the space resolution or the line edge roughness. As a model compound of a resist resin, liquid n-dodecane was used as a sample. The experiment was carried out using the subpicosecond pulse radiolysis. The experimental data was analyzed by Monte Carlo simulation based on the diffusion in an electric field. The simulation data were convoluted by the response function and fitted to the experimental data. By transforming the time-dependent behavior of cation radicals to the distribution function of cation radical-electron distance, the time-dependent distribution was obtained. Subsequently, the relation between the space resolution and the space distribution of ionic species was discussed. (author)

  6. Study of electron temperature evolution during sawtoothing and pellet injection using thermal electron cyclotron emission in the Alcator C tokamak

    International Nuclear Information System (INIS)

    Gomez, C.C.

    1986-05-01

    A study of the electron temperature evolution has been performed using thermal electron cyclotron emission. A six channel far infrared polychromator was used to monitor the radiation eminating from six radial locations. The time resolution was <3 μs. Three events were studied, the sawtooth disruption, propagation of the sawtooth generated heatpulse and the electron temperature response to pellet injection. The sawtooth disruption in Alcator takes place in 20 to 50 μs, the energy mixing radius is approx. 8 cm or a/2. It is shown that this is inconsistent with single resonant surface Kadomtsev reconnection. Various forms of scalings for the sawtooth period and amplitude were compared. The electron heatpulse propagation has been used to estimate chi e(the electron thermal diffusivity). The fast temperature relaxation observed during pellet injection has also been studied. Electron temperature profile reconstructions have shown that the profile shape can recover to its pre-injection form in a time scale of 200 μs to 3 ms depending on pellet size

  7. A low temperature cryostat with a refrigerator for studying electron-irradiation effects on solids, 2

    International Nuclear Information System (INIS)

    Oka, Takashi; Yoshida, Toshio; Shono, Yoshihiko

    1978-01-01

    A convenient cryostat with a small cryogenic refrigerator for studying electron-irradiation effects on solids is reported. The lowest temperature at the sample room is about 10 K or less. In a temperature region below 80 K, the sample temperature can be controlled within 0.05 K. (auth.)

  8. Ionic transport in P(VdF–HFP)–PEO based novel microporous ...

    Indian Academy of Sciences (India)

    Administrator

    hexafluoropropylene) [P(VdF–HFP)] and polyethylene oxide (PEO) was prepared by phase inversion tech- nique. ... new consumer electronic technologies such as cell phones, notebook PC and ... methanol, pentane, ethanol, hexane or their binary mix- ture and .... Figure 6. Temperature dependence of ionic conductivity of.

  9. Electron-electron attractive interaction in Maxwell-Chern-Simons QED3 at zero temperature

    International Nuclear Information System (INIS)

    Belich, H.; Ferreira Junior, M.M.; Helayel-Neto, J.A.; Ferreira Junior, M.M.

    2001-04-01

    One discusses the issue of low-energy electron-electron bound states in the Maxwell-Chern-Simons model coupled to QED 3 with spontaneous breaking of a local U(1)-symmetry. The scattering potential, in the non-relativistic limit, steaming from the electron-electron Moeller scattering, mediated by the Maxwell-Chern-Simons-Proca gauge field and the Higgs scalar, might be attractive by fine-tuning properly the physical parameters of the model. (author)

  10. The electron density and temperature distributions predicted by bow shock models of Herbig-Haro objects

    International Nuclear Information System (INIS)

    Noriega-Crespo, A.; Bohm, K.H.; Raga, A.C.

    1990-01-01

    The observable spatial electron density and temperature distributions for series of simple bow shock models, which are of special interest in the study of Herbig-Haro (H-H) objects are computed. The spatial electron density and temperature distributions are derived from forbidden line ratios. It should be possible to use these results to recognize whether an observed electron density or temperature distribution can be attributed to a bow shock, as is the case in some Herbig-Haro objects. As an example, the empirical and predicted distributions for H-H 1 are compared. The predicted electron temperature distributions give the correct temperature range and they show very good diagnostic possibilities if the forbidden O III (4959 + 5007)/4363 wavelength ratio is used. 44 refs

  11. Effects of rf power on electron density and temperature, neutral temperature, and Te fluctuations in an inductively coupled plasma

    International Nuclear Information System (INIS)

    Camparo, James; Fathi, Gilda

    2009-01-01

    Atomic clocks that fly on global-navigation satellites such as global positioning system (GPS) and Galileo employ light from low-temperature, inductively coupled plasmas (ICPs) for atomic signal generation and detection (i.e., alkali/noble-gas rf-discharge lamps). In this application, the performance of the atomic clock and the capabilities of the navigation system depend sensitively on the stability of the ICP's optical emission. In order to better understand the mechanisms that might lead to instability in these rf-discharge lamps, and hence the satellite atomic clocks, we studied the optical emission from a Rb/Xe ICP as a function of the rf power driving the plasma. Surprisingly, we found that the electron density in the plasma was essentially independent of increases in rf power above its nominal value (i.e., 'rf-power gain') and that the electron temperature was only a slowly varying function of rf-power gain. The primary effect of rf power was to increase the temperature of the neutrals in the plasma, which was manifested by an increase in Rb vapor density. Interestingly, we also found evidence for electron temperature fluctuations (i.e., fluctuations in the plasma's high-energy electron content). The variance of these fluctuations scaled inversely with the plasma's mean electron temperature and was consistent with a simple model that assumed that the total electron density in the discharge was independent of rf power. Taken as a whole, our results indicate that the electrons in alkali/noble-gas ICPs are little affected by slight changes in rf power and that the primary effect of such changes is to heat the plasma's neutral species.

  12. Anomaly in the Kumakhov radiation temperature dependence at axial channeling of electrons

    Energy Technology Data Exchange (ETDEWEB)

    Komarov, F.F.; Telegin, V.I.; Khokonov, M.Kh.

    1983-01-01

    The results of numerical solution of a kinetic equation for distribution function of axially channelled electrons obtained by Belostritsky and Kumakhov at different temperatures of crystals and calculated for the determined electron distributions spectral density of radiation are given. Analysis of the obtained dependence of the number of channelled 5 GeV electrons in tungsten along the <111> axis on depth Z has revealed that 2% of incidence beam electrons have anomalously large depths of dechannelling. Ratio of electrons with large by modulus cross section energies grows at decreasing crystal temperature from 293 to 40 K and, therefore, radiation intensity increases. Two-fold increase of radiation intensity can be attained at axial channelling of 1 GeV electrons in tungsten <111> at the temperatures of the crystal equal to 40 and 293 K and its thickness equal to 220 ..mu..m.

  13. Temperature Dependence of the Spin-Hall Conductivity of a Two-Dimensional Impure Rashba Electron Gas in the Presence of Electron-Phonon and Electron-Electron Interactions

    Science.gov (United States)

    Yavari, H.; Mokhtari, M.; Bayervand, A.

    2015-03-01

    Based on Kubo's linear response formalism, temperature dependence of the spin-Hall conductivity of a two-dimensional impure (magnetic and nonmagnetic impurities) Rashba electron gas in the presence of electron-electron and electron-phonon interactions is analyzed theoretically. We will show that the temperature dependence of the spin-Hall conductivity is determined by the relaxation rates due to these interactions. At low temperature, the elastic lifetimes ( and are determined by magnetic and nonmagnetic impurity concentrations which are independent of the temperature, while the inelastic lifetimes ( and related to the electron-electron and electron-phonon interactions, decrease when the temperature increases. We will also show that since the spin-Hall conductivity is sensitive to temperature, we can distinguish the intrinsic and extrinsic contributions.

  14. Role of 3d electrons in formation of ionic-covalent bonds in II-VI based ternary compounds

    International Nuclear Information System (INIS)

    Lawniczak-Jablonska, K.; Iwanowski, R.J.; Perera, R.C.C.

    1997-01-01

    In the II-VI compounds doped with transition metals (diluted magnetic semiconductors) a substitution of cation by the introduced magnetic ion leads to hybridization of its 3d states with the sp states of the host semiconductor. The degree of hybridization of the 3d states and its interaction with the host material band states has been a subject of numerous discussions. Inner shell absorption spectroscopy provides very useful means of electronic structure analysis in a wide variety of systems. Due to its selectivity for atomic species and the selection rules for electron transitions, the soft X-ray absorption technique offers quite unique opportunity to measure directly the site-selective local density of the unoccupied d states in the compounds studied. Results are reported for ZnS compounds with Mn, Fe, Co or Ni substitutions for Zn

  15. Radiation Chemistry and Photochemistry of Ionic Liquids

    International Nuclear Information System (INIS)

    Wishart, J.F.; Takahaski, K.

    2010-01-01

    As our understanding of ionic liquids and their tunable properties has grown, it is possible to see many opportunities for ionic liquids to contribute to the sustainable use of energy. The potential safety and environmental benefits of ionic liquids, as compared to conventional solvents, have attracted interest in their use as processing media for the nuclear fuel cycle. Therefore, an understanding of the interactions of ionizing radiation and photons with ionic liquids is strongly needed. However, the radiation chemistry of ionic liquids is still a relatively unexplored topic although there has been a significant increase in the number of researchers in the field recently. This article provides a brief introduction to ionic liquids and their interesting properties, and recent advances in the radiation chemistry and photochemistry of ionic liquids. In this article, we will mainly focus on excess electron dynamics and radical reaction dynamics. Because solvation dynamics processes in ionic liquids are much slower than in molecular solvents, one of the distinguishing characteristics is that pre-solvated electrons play an important role in ionic liquid radiolysis. It will be also shown that the reaction dynamics of radical ions is significantly different from that observed in molecular solvents because of the Coulombic screening effects and electrostatic interactions in ionic liquids.

  16. Volumetric properties of room temperature ionic liquid 1. The system of {l_brace}1-methyl-3-ethylimidazolium ethyl sulfate+water{r_brace} at temperature in the range (278.15 to 333.15) K

    Energy Technology Data Exchange (ETDEWEB)

    Lu Xingmei [Department of Chemistry, Shenyang Normal University, Shenyang 110034 (China); Department of Chemistry, Liaoning University, Shenyang 110036 (China); Xu Weiguo [Institute of Salt Lakes, Chinese Academy of Science, Xining 810008 (China); Gui Jinsong [Department of Chemistry, Shenyang Normal University, Shenyang 110034 (China); Li Huawei [Department of Chemistry, Shenyang Normal University, Shenyang 110034 (China); Yang Jiazhen [Institute of Salt Lakes, Chinese Academy of Science, Xining 810008 (China)]. E-mail: jzyanglnu@yahoo.com.cn

    2005-01-01

    This paper reports densities of aqueous solutions of ionic liquid (IL) 1-methyl-3-ethylimidazolium ethyl sulfate (EMISE) that were measured gravimetrically at temperatures (278.15 to 333.15) K. The values of the apparent molar volume, {sup {phi}}V{sub B} and partial molar volume, V-bar B, were determined and apparent molar expansibilities {sup {phi}}E=(({partial_derivative}{phi}{sub B})/{partial_derivative}T)){sub p} of EMISE and the coefficients of thermal expansion of the solutions, {alpha}, were calculated. The values of the apparent molar volume, {sup {phi}}V{sub B}, were fitted by the method of least-squares to a Pitzer's equation to determine the parameters, {beta}{sub MX}{sup (0)V}, {beta}{sub MX}{sup (1)V}, and C{sub MX}{sup V}.

  17. Volumetric properties of room temperature ionic liquid 1. The system of {1-methyl-3-ethylimidazolium ethyl sulfate+water} at temperature in the range (278.15 to 333.15) K

    International Nuclear Information System (INIS)

    Lu Xingmei; Xu Weiguo; Gui Jinsong; Li Huawei; Yang Jiazhen

    2005-01-01

    This paper reports densities of aqueous solutions of ionic liquid (IL) 1-methyl-3-ethylimidazolium ethyl sulfate (EMISE) that were measured gravimetrically at temperatures (278.15 to 333.15) K. The values of the apparent molar volume, φ V B and partial molar volume, V-bar B, were determined and apparent molar expansibilities φ E=((∂φ B )/∂T)) p of EMISE and the coefficients of thermal expansion of the solutions, α, were calculated. The values of the apparent molar volume, φ V B , were fitted by the method of least-squares to a Pitzer's equation to determine the parameters, β MX (0)V , β MX (1)V , and C MX V

  18. Hotspot electron temperature from x-ray continuum measurements on the NIF

    International Nuclear Information System (INIS)

    Jarrott, L. C.; Benedetti, L. R.; Chen, H.; Izumi, N.; Khan, S. F.; Ma, T.; Nagel, S. R.; Landen, O. L.; Pak, A.; Patel, P. K.; Schneider, M.; Scott, H. A.

    2016-01-01

    We report on measurements of the electron temperature in the hotspot of inertially confined, layered, spherical implosions on the National Ignition Facility using a differential filtering diagnostic. Measurements of the DT and DD ion temperatures using neutron time-of-flight detectors are complicated by the contribution of hot spot motion to the peak width, which produce an apparent temperature higher than the thermal temperature. The electron temperature is not sensitive to this non-thermal velocity and is thus a valuable input to interpreting the stagnated hot spot conditions. Here we show that the current differential filtering diagnostic provides insufficient temperature resolution for the hot spot temperatures of interest. We then propose a new differential filter configuration utilizing larger pinhole size to increase spectral fluence, as well as thicker filtration. This new configuration will improve measurement uncertainty by more than a factor of three, allowing for a more accurate hotspot temperature.

  19. Hotspot electron temperature from x-ray continuum measurements on the NIF

    Science.gov (United States)

    Jarrott, L. C.; Benedetti, L. R.; Chen, H.; Izumi, N.; Khan, S. F.; Ma, T.; Nagel, S. R.; Landen, O. L.; Pak, A.; Patel, P. K.; Schneider, M.; Scott, H. A.

    2016-11-01

    We report on measurements of the electron temperature in the hotspot of inertially confined, layered, spherical implosions on the National Ignition Facility using a differential filtering diagnostic. Measurements of the DT and DD ion temperatures using neutron time-of-flight detectors are complicated by the contribution of hot spot motion to the peak width, which produce an apparent temperature higher than the thermal temperature. The electron temperature is not sensitive to this non-thermal velocity and is thus a valuable input to interpreting the stagnated hot spot conditions. Here we show that the current differential filtering diagnostic provides insufficient temperature resolution for the hot spot temperatures of interest. We then propose a new differential filter configuration utilizing larger pinhole size to increase spectral fluence, as well as thicker filtration. This new configuration will improve measurement uncertainty by more than a factor of three, allowing for a more accurate hotspot temperature.

  20. Hotspot electron temperature from x-ray continuum measurements on the NIF.

    Science.gov (United States)

    Jarrott, L C; Benedetti, L R; Chen, H; Izumi, N; Khan, S F; Ma, T; Nagel, S R; Landen, O L; Pak, A; Patel, P K; Schneider, M; Scott, H A

    2016-11-01

    We report on measurements of the electron temperature in the hotspot of inertially confined, layered, spherical implosions on the National Ignition Facility using a differential filtering diagnostic. Measurements of the DT and DD ion temperatures using neutron time-of-flight detectors are complicated by the contribution of hot spot motion to the peak width, which produce an apparent temperature higher than the thermal temperature. The electron temperature is not sensitive to this non-thermal velocity and is thus a valuable input to interpreting the stagnated hot spot conditions. Here we show that the current differential filtering diagnostic provides insufficient temperature resolution for the hot spot temperatures of interest. We then propose a new differential filter configuration utilizing larger pinhole size to increase spectral fluence, as well as thicker filtration. This new configuration will improve measurement uncertainty by more than a factor of three, allowing for a more accurate hotspot temperature.

  1. Hotspot electron temperature from x-ray continuum measurements on the NIF

    Energy Technology Data Exchange (ETDEWEB)

    Jarrott, L. C., E-mail: jarrott1@llnl.gov; Benedetti, L. R.; Chen, H.; Izumi, N.; Khan, S. F.; Ma, T.; Nagel, S. R.; Landen, O. L.; Pak, A.; Patel, P. K.; Schneider, M.; Scott, H. A. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States)

    2016-11-15

    We report on measurements of the electron temperature in the hotspot of inertially confined, layered, spherical implosions on the National Ignition Facility using a differential filtering diagnostic. Measurements of the DT and DD ion temperatures using neutron time-of-flight detectors are complicated by the contribution of hot spot motion to the peak width, which produce an apparent temperature higher than the thermal temperature. The electron temperature is not sensitive to this non-thermal velocity and is thus a valuable input to interpreting the stagnated hot spot conditions. Here we show that the current differential filtering diagnostic provides insufficient temperature resolution for the hot spot temperatures of interest. We then propose a new differential filter configuration utilizing larger pinhole size to increase spectral fluence, as well as thicker filtration. This new configuration will improve measurement uncertainty by more than a factor of three, allowing for a more accurate hotspot temperature.

  2. Nonlocal collisionless and collisional electron transport in low temperature plasmas

    Science.gov (United States)

    Kaganovich, Igor

    2009-10-01

    The purpose of the talk is to describe recent advances in nonlocal electron kinetics in low-pressure plasmas. A distinctive property of partially ionized plasmas is that such plasmas are always in a non-equilibrium state: the electrons are not in thermal equilibrium with the neutral species and ions, and the electrons are also not in thermodynamic equilibrium within their own ensemble, which results in a significant departure of the electron velocity distribution function from a Maxwellian. These non-equilibrium conditions provide considerable freedom to choose optimal plasma parameters for applications, which make gas discharge plasmas remarkable tools for a variety of plasma applications, including plasma processing, discharge lighting, plasma propulsion, particle beam sources, and nanotechnology. Typical phenomena in such discharges include nonlocal electron kinetics, nonlocal electrodynamics with collisionless electron heating, and nonlinear processes in the sheaths and in the bounded plasmas. Significant progress in understanding the interaction of electromagnetic fields with real bounded plasma created by this field and the resulting changes in the structure of the applied electromagnetic field has been one of the major achievements of the last decade in this area of research [1-3]. We show on specific examples that this progress was made possible by synergy between full scale particle-in-cell simulations, analytical models, and experiments. In collaboration with Y. Raitses, A.V. Khrabrov, Princeton Plasma Physics Laboratory, Princeton, NJ, USA; V.I. Demidov, UES, Inc., 4401 Dayton-Xenia Rd., Beavercreek, OH 45322, USA and AFRL, Wright-Patterson AFB, OH 45433, USA; and D. Sydorenko, University of Alberta, Edmonton, Canada. [4pt] [1] D. Sydorenko, A. Smolyakov, I. Kaganovich, and Y. Raitses, IEEE Trans. Plasma Science 34, 895 (2006); Phys. Plasmas 13, 014501 (2006); 14 013508 (2007); 15, 053506 (2008). [0pt] [2] I. D. Kaganovich, Y. Raitses, D. Sydorenko, and

  3. SiGe Based Low Temperature Electronics for Lunar Surface Applications

    Science.gov (United States)

    Mojarradi, Mohammad M.; Kolawa, Elizabeth; Blalock, Benjamin; Cressler, John

    2012-01-01

    The temperature at the permanently shadowed regions of the moon's surface is approximately -240 C. Other areas of the lunar surface experience temperatures that vary between 120 C and -180 C during the day and night respectively. To protect against the large temperature variations of the moon surface, traditional electronics used in lunar robotics systems are placed inside a thermally controlled housing which is bulky, consumes power and adds complexity to the integration and test. SiGe Based electronics have the capability to operate over wide temperature range like that of the lunar surface. Deploying low temperature SiGe electronics in a lander platform can minimize the need for the central thermal protection system and enable the development of a new generation of landers and mobility platforms with highly efficient distributed architecture. For the past five years a team consisting of NASA, university and industry researchers has been examining the low temperature and wide temperature characteristic of SiGe based transistors for developing electronics for wide temperature needs of NASA environments such as the Moon, Titan, Mars and Europa. This presentation reports on the status of the development of wide temperature SiGe based electronics for the landers and lunar surface mobility systems.

  4. Mite Biodiversity Under the Low Temperature Scanning Electron Microscope

    Science.gov (United States)

    To date, more than 55,000 mite species have been described and only a few of them have been studied. Some mites are adapted to live deep in soil, others in fresh or sea water, some are on plants, algae, fungi or animals, and others are able to survive in both extreme cold and hot temperatures. The...

  5. Dual – Temperature Electron distribution in a Laboratory Plasma ...

    African Journals Online (AJOL)

    The dual-temperature distribution function is used to investigate theoretically the effect of a perturbation of Maxwell distribution function on density ratios in a laboratory plasma produced solely by collision. By assuming a foreknowledge of collision coefficients and cross-sections and an atomic model which sets at two ...

  6. Defects in low temperature electron irradiated InP

    International Nuclear Information System (INIS)

    Suski, J.; Bourgoin, J.

    1984-01-01

    n and p-InP has been irradiated at 25K with 1MeV electrons and the created defects were studied by deep level transient spectroscopy (DLTS) in the range 25K-400K. In n-InP, four traps are directly observed, with low introduction rates except for one. They anneal in three stages, and four new centers of still lower concentration appear after 70 0 C heat treatment. In p-InP, two dominant traps stable up to approx.= 400K with introduction rates close to the theoretical ones, which might be primary defects are found, while another one is clearly a secondary defect likely associated to Zn dopant. At least two of the low concentration irradiation induced electron traps, created between 25K and 100K are also secondary defects, which implies a mobility of some primary defects down to 100K at least. (author)

  7. Direct electrochemistry and electrocatalysis of heme proteins immobilised in carbon-coated nickel magnetic nanoparticle-chitosan-dimethylformamide composite films in room-temperature ionic liquids.

    Science.gov (United States)

    Wang, Ting; Wang, Lu; Tu, Jiaojiao; Xiong, Huayu; Wang, Shengfu

    2013-12-01

    The direct electrochemistry and electrocatalysis of heme proteins entrapped in carbon-coated nickel magnetic nanoparticle-chitosan-dimethylformamide (CNN-CS-DMF) composite films were investigated in the hydrophilic ionic liquid [bmim][BF4]. The surface morphologies of a representative set of films were characterised via scanning electron microscopy. The proteins immobilised in the composite films were shown to retain their native secondary structure using UV-vis spectroscopy. The electrochemical performance of the heme proteins-CNN-CS-DMF films was evaluated via cyclic voltammetry and chronoamperometry. A pair of stable and well-defined redox peaks was observed for the heme protein films at formal potentials of -0.151 V (HRP), -0.167 V (Hb), -0.155 V (Mb) and -0.193 V (Cyt c) in [bmim][BF4]. Moreover, several electrochemical parameters of the heme proteins were calculated by nonlinear regression analysis of the square-wave voltammetry. The addition of CNN significantly enhanced not only the electron transfer of the heme proteins but also their electrocatalytic activity toward the reduction of H2O2. Low apparent Michaelis-Menten constants were obtained for the heme protein-CNN-CS-DMF films, demonstrating that the biosensors have a high affinity for H2O2. In addition, the resulting electrodes displayed a low detection limit and improved sensitivity for detecting H2O2, which indicates that the biocomposite film can serve as a platform for constructing new non-aqueous biosensors for real detection. Copyright © 2013 Elsevier B.V. All rights reserved.

  8. Junction Temperature Control for More Reliable Power Electronics

    DEFF Research Database (Denmark)

    Andresen, Markus; Ma, Ke; Buticchi, Giampaolo

    2018-01-01

    The thermal stress of power electronic components is one of the most important causes of their failure. Proper thermal management plays an important role for more reliable and cost-effective energy conversion. As one of the most vulnerable and expensive components, power semiconductor components ...... the desired cost-benefit tradeoff. This paper analyzes also the many open questions of this research area. Among them, it is worth highlighting that a verification of the actual lifetime extension is still missing....

  9. Blocking layer modeling for temperature analysis of electron transfer ...

    African Journals Online (AJOL)

    In this article, we simulate thermal effects on the electron transfer rate from three quantum dots CdSe, CdS and CdTe to three metal oxides TiO2, SnO2 and ZnO2 in the presence of four blocking layers ZnS, ZnO, TiO2 and Al2O3, in a porous quantum dot sensitized solar cell (QDSSC) structure, using Marcus theory.

  10. Trace mercury determination in drinking and natural water samples by room temperature ionic liquid based-preconcentration and flow injection-cold vapor atomic absorption spectrometry.

    Science.gov (United States)

    Martinis, Estefanía M; Bertón, Paula; Olsina, Roberto A; Altamirano, Jorgelina C; Wuilloud, Rodolfo G

    2009-08-15

    A liquid-liquid extraction procedure (L-L) based on room temperature ionic liquid (RTIL) was developed for the preconcentration and determination of mercury in different water samples. The analyte was quantitatively extracted with 1-butyl-3-methylimidazolium hexafluorophosphate ([C(4)mim][PF(6)]) under the form of Hg-2-(5-bromo-2-pyridylazo)-5-diethylaminophenol (Hg-5-Br-PADAP) complex. A volume of 500 microl of 9.0 mol L(-1) hydrochloric acid was used to back-extract the analyte from the RTIL phase into an aqueous media prior to its analysis by flow injection-cold vapor atomic absorption spectrometry (FI-CV-AAS). A preconcentration factor of 36 was achieved upon preconcentration of 20 mL of sample. The limit of detection (LOD) obtained under the optimal conditions was 2.3ngL(-1) and the relative standard deviation (RSD) for 10 replicates at 1 microg L(-1) Hg(2+) was 2.8%, calculated with peaks height. The method was successfully applied to the determination of mercury in river, sea, mineral and tap water samples and a certified reference material (CRM).

  11. Trace mercury determination in drinking and natural water samples by room temperature ionic liquid based-preconcentration and flow injection-cold vapor atomic absorption spectrometry

    International Nuclear Information System (INIS)

    Martinis, Estefania M.; Berton, Paula; Olsina, Roberto A.; Altamirano, Jorgelina C.; Wuilloud, Rodolfo G.

    2009-01-01

    A liquid-liquid extraction procedure (L-L) based on room temperature ionic liquid (RTIL) was developed for the preconcentration and determination of mercury in different water samples. The analyte was quantitatively extracted with 1-butyl-3-methylimidazolium hexafluorophosphate ([C 4 mim][PF 6 ]) under the form of Hg-2-(5-bromo-2-pyridylazo)-5-diethylaminophenol (Hg-5-Br-PADAP) complex. A volume of 500 μl of 9.0 mol L -1 hydrochloric acid was used to back-extract the analyte from the RTIL phase into an aqueous media prior to its analysis by flow injection-cold vapor atomic absorption spectrometry (FI-CV-AAS). A preconcentration factor of 36 was achieved upon preconcentration of 20 mL of sample. The limit of detection (LOD) obtained under the optimal conditions was 2.3 ng L -1 and the relative standard deviation (RSD) for 10 replicates at 1 μg L -1 Hg 2+ was 2.8%, calculated with peaks height. The method was successfully applied to the determination of mercury in river, sea, mineral and tap water samples and a certified reference material (CRM).

  12. Sorption properties of Th(IV) on the raw diatomite-Effects of contact time, pH, ionic strength and temperature

    International Nuclear Information System (INIS)

    Sheng Guodong; Hu Jun; Wang Xiangke

    2008-01-01

    Diatomite has a number of unique physicochemical properties and has diversified industrial uses. Natural diatomite has been tested as a potential sorbent for the removal of Th(IV) from aqueous solutions. The results indicate that sorption of Th(IV) is strongly dependent on ionic strength at pH 3. Outer-sphere complexation or ion exchange may be the main sorption mechanism of Th(IV) to diatomite at low pH values, whereas the sorption of Th(IV) at pH>3 is mainly dominated by inner-sphere complexation or precipitation. The competition for Th(IV) between aqueous or surface adsorbed anions (e.g., herein ClO 4 - , NO 3 - and Cl - ) and surface functional groups of diatomite is important for Th(IV) sorption. The thermodynamic data (ΔH 0 , ΔS 0 , ΔG 0 ) are calculated from the temperature-dependent sorption isotherms. The results suggest that sorption process of Th(IV) on diatomite is spontaneous and endothermic

  13. Non-ideal behaviour of imidazolium based room temperature ionic liquids in ethylene glycol at T = (298.15 to 318.15) K

    International Nuclear Information System (INIS)

    Singh, Tejwant; Kumar, Arvind; Kaur, Mandeep; Kaur, Gurpreet; Kumar, H.

    2009-01-01

    Non-ideal behaviour of the room temperature ionic liquids (RTILs), 1-butyl-3-methylimidazolium tetrafluoroborate [bmim][BF 4 ]; 1-octyl-3-methylimidazolium tetrafluoroborate [omim][BF 4 ] and 1-butyl-3-methylimidazolium octylsulfate [bmim][C 8 OSO 3 ] in ethylene glycol [HOCH 2 CH 2 OH] (EG) have been investigated over the whole composition range at T = (298.15 to 318.15) K. For the purpose, volumetric properties such as excess molar volumes, V m E , apparent molar volumes, V φ,i , partial molar volumes, V-bar m,i , excess partial molar volumes, V-bar m,i E , and their limiting values at infinite dilution, V φ,i ∞ , V-bar m,i ∞ , and V-bar m,i E,∞ respectively have been calculated from the experimental density measurements. The V m E results have been analyzed using the Prigogine-Flory-Patterson (PFP) theory. PFP theory has satisfactorily explained the volumetric behaviour of the binary mixtures. Refractive index measurements at 298.15 K have been used to calculate the deviations in refractive indices Δ φ n and the deviation of molar refraction Δ x R from their respective ideal values. Refractive index results have been correlated with volumetric results, and have been interpreted in terms of molecular interactions. Excess properties are fitted to the Redlich-Kister polynomial equation to obtain the binary coefficients and the standard errors.

  14. Ultrasonic Relaxation Study of 1-Alkyl-3-methylimidazolium-Based Room-Temperature Ionic Liquids: Probing the Role of Alkyl Chain Length in the Cation.

    Science.gov (United States)

    Zorębski, Michał; Zorębski, Edward; Dzida, Marzena; Skowronek, Justyna; Jężak, Sylwia; Goodrich, Peter; Jacquemin, Johan

    2016-04-14

    Ultrasound absorption spectra of four 1-alkyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imides were determined as a function of the alkyl chain length on the cation from 1-propyl to 1-hexyl from 293.15 to 323.15 K at ambient pressure. Herein, the ultrasound absorption measurements were carried out using a standard pulse technique within a frequency range from 10 to 300 MHz. Additionally, the speed of sound, density, and viscosity have been measured. The presence of strong dissipative processes during the ultrasound wave propagation was found experimentally, i.e., relaxation processes in the megahertz range were observed for all compounds over the whole temperature range. The relaxation spectra (both relaxation amplitude and relaxation frequency) were shown to be dependent on the alkyl side chain length of the 1-alkyl-3-methylimidazolium ring. In most cases, a single-Debye model described the absorption spectra very well. However, a comparison of the determined spectra with the spectra of a few other imidazolium-based ionic liquids reported in the literature (in part recalculated in this work) shows that the complexity of the spectra increases rapidly with the elongation of the alkyl chain length on the cation. This complexity indicates that both the volume viscosity and the shear viscosity are involved in relaxation processes even in relatively low frequency ranges. As a consequence, the sound velocity dispersion is present at relatively low megahertz frequencies.

  15. Study of the effect of tribo-materials and surface finish on the lubricant performance of new halogen-free room temperature ionic liquids

    Science.gov (United States)

    Saurín, N.; Minami, I.; Sanes, J.; Bermúdez, M. D.

    2016-03-01

    The present work evaluates different materials and surface finish in the presence of newly designed, hydrophobic halogen-free room temperature ionic liquids (RTILs) as lubricants. A reciprocating tribo-tester was employed with steel-ceramic and steel-thermosetting epoxy resin contacts under boundary lubrication conditions. Four different tetraalkylphosphonium organosilanesulfonate RTILs provided excellent lubricating performance, with friction coefficients as low as 0.057, and non-measurable wear for the higher roughness machine-finish stainless steel flat against sapphire balls, in the case of the lubricants containing the 2-trimethylsilylethanesulfonate anion. Higher friction coefficients of the order of 0.1 and wear volumes of the order of 10-4 mm3 were observed for the lower roughness fine-finished flat stainless steel surface. All RTILs prevent wear of epoxy resin against stainless steel balls, with friction coefficients in the range of 0.03-0.06. EDX analysis shows the presence of RTILs on the stainless steel surfaces after the tribological tests. Under the experimental conditions, no corrosive processes were observed.

  16. Liquid-liquid extraction to lithium isotope separation based on room-temperature ionic liquids containing 2,2'-binaphthyldiyl-17-crown-5

    International Nuclear Information System (INIS)

    Sun Xiaoli; Zhou Wen; Gu Lin; Qiu Dan; Ren Donghong; Gu Zhiguo; Li Zaijun

    2015-01-01

    A novel liquid-liquid extraction system was investigated for the selective separation of lithium isotopes using ionic liquids (ILs = C 8 mim + PF 6 - , C 8 mim + BF 4 - , and C 8 mim + NTf 2 - ) as extraction solvent and 2,2'-binaphthyldiyl-17-crown-5 (BN-17-5) as extractant. The effects of the concentration of lithium salt, counter anion of lithium salt, initial pH of aqueous phase, extraction temperature, and time on the lithium isotopes separation were discussed. Under optimized conditions, the maximum single-stage separation factor α of 6 Li/ 7 Li obtained in the present study was 1.046 ± 0.002, indicating the lighter isotope 6 Li was enriched in IL phase while the heavier isotope 7 Li was concentrated in the solution phase. The formation of 1:1 complex Li(BN-17-5) + in the IL phase was determined on the basis of slope analysis method. The large value of the free energy change (-ΔG° = 92.89 J mol -1 ) indicated the high separation capability of the Li isotopes by BN-17-5/IL system. Lithium in Li(BN-17-5) + complex was stripped by 1 mol L -1 HCl solution. The extraction system offers high efficiency, simplicity, and green application prospect to lithium isotope separation. (author)

  17. Sorption properties of Th(IV) on the raw diatomite--effects of contact time, pH, ionic strength and temperature.

    Science.gov (United States)

    Sheng, Guodong; Hu, Jun; Wang, Xiangke

    2008-10-01

    Diatomite has a number of unique physicochemical properties and has diversified industrial uses. Natural diatomite has been tested as a potential sorbent for the removal of Th(IV) from aqueous solutions. The results indicate that sorption of Th(IV) is strongly dependent on ionic strength at pH3. Outer-sphere complexation or ion exchange may be the main sorption mechanism of Th(IV) to diatomite at low pH values, whereas the sorption of Th(IV) at pH>3 is mainly dominated by inner-sphere complexation or precipitation. The competition for Th(IV) between aqueous or surface adsorbed anions (e.g., herein ClO(4)(-), NO(3)(-) and Cl(-)) and surface functional groups of diatomite is important for Th(IV) sorption. The thermodynamic data (DeltaH(0), DeltaS(0), DeltaG(0)) are calculated from the temperature-dependent sorption isotherms. The results suggest that sorption process of Th(IV) on diatomite is spontaneous and endothermic.

  18. Formation of presheath and current-free double layer in a two-electron-temperature plasma

    International Nuclear Information System (INIS)

    Sato, Kunihiro; Miyawaki, Fujio

    1992-02-01

    Development of the steady-state potential in a two-temperature-electron plasma in contact with the wall is investigated analytically. It is shown that if the hot- to cold electron temperature ratio is greater than ten, the potential drop in the presheath, which is allowed to have either a small value characterized by the cold electrons or a large value by the hot electrons, discontinuously changes at a critical value for the hot- to total electron density ratio. It is also found that the monotonically decreasing potential structure which consists of the first presheath, a current-free double layer, the second presheath, and the sheath can be steadily formed in a lower range of the hot- to total electron density ratio around the critical value. The current-free double layer is set up due to existence of the two electron species and cold ions generated by ionization so as to connect two presheath potentials at different levels. (author)

  19. On the electron-ion temperature ratio established by collisionless shocks

    Science.gov (United States)

    Vink, Jacco; Broersen, Sjors; Bykov, Andrei; Gabici, Stefano

    2015-07-01

    Astrophysical shocks are often collisionless shocks, in which the changes in plasma flow and temperatures across the shock are established not through Coulomb interactions, but through electric and magnetic fields. An open question about collisionless shocks is whether electrons and ions each establish their own post-shock temperature (non-equilibration of temperatures), or whether they quickly equilibrate in the shock region. Here we provide a simple, thermodynamic, relation for the minimum electron-ion temperature ratios that should be expected as a function of Mach number. The basic assumption is that the enthalpy-flux of the electrons is conserved separately, but that all particle species should undergo the same density jump across the shock, in order for the plasma to remain charge neutral. The only form of additional electron heating that we allow for is adiabatic heating, caused by the compression of the electron gas. These assumptions result in an analytic treatment of expected electron-ion temperature ratio that agrees with observations of collisionless shocks: at low sonic Mach numbers, Ms ≲ 2, the electron-ion temperature ratio is close to unity, whereas for Mach numbers above Ms ≈ 60 the electron-ion temperature ratio asymptotically approaches a temperature ratio of Te/Ti = me/ ⟨ mi ⟩. In the intermediate Mach number range the electron-ion temperature ratio scales as Te/Ti ∝ Ms-2. In addition, we calculate the electron-ion temperature ratios under the assumption of adiabatic heating of the electrons only, which results in a higher electron-ion temperature ratio, but preserves the Te/Ti ∝ Ms-2 scaling. We also show that for magnetised shocks the electron-ion temperature ratio approaches the asymptotic value Te/Ti = me/ ⟨ mi ⟩ for lower magnetosonic Mach numbers (Mms), mainly because for a strongly magnetised shock the sonic Mach number is larger than the magnetosonic Mach number (Mms ≤ Ms). The predicted scaling of the electron

  20. Using Three-Body Recombination to Extract Electron Temperatures of Ultracold Plasmas

    International Nuclear Information System (INIS)

    Fletcher, R. S.; Zhang, X. L.; Rolston, S. L.

    2007-01-01

    Three-body recombination, an important collisional process in plasmas, increases dramatically at low electron temperatures, with an accepted scaling of T e -9/2 . We measure three-body recombination in an ultracold neutral xenon plasma by detecting recombination-created Rydberg atoms using a microwave-ionization technique. With the accepted theory (expected to be applicable for weakly coupled plasmas) and our measured rates, we extract the plasma temperatures, which are in reasonable agreement with previous measurements early in the plasma lifetime. The resulting electron temperatures indicate that the plasma continues to cool to temperatures below 1 K